Towards clinical assessment of velopharyngeal closure using MRI: evaluation of real-time MRI sequences at 1.5 and 3 T

Objective

The objective of this study was to demonstrate soft palate MRI at 1.5 and 3 T with high temporal resolution on clinical scanners.

Methods

Six volunteers were imaged while speaking, using both four real-time steady-state free-precession (SSFP) sequences at 3 T and four balanced SSFP (bSSFP) at 1.5 T. Temporal resolution was 9–20 frames s⁻¹ (fps), spatial resolution 1.6×1.6×10.0–2.7×2.7×10.0 mm³. Simultaneous audio was recorded. Signal-to-noise ratio (SNR), palate thickness and image quality score (1–4, non-diagnostic–excellent) were evaluated.

Results

SNR was higher at 3 T than 1.5 T in the relaxed palate (nasal breathing position) and reduced in the elevated palate at 3 T, but not 1.5 T. Image quality was not significantly different between field strengths or sequences (p=NS). At 3 T, 40% acquisitions scored 2 and 56% scored 3. Most 1.5 T acquisitions scored 1 (19%) or 4 (46%). Image quality was more dependent on subject or field than sequence. SNR in static images was highest with 1.9×1.9×10.0 mm³ resolution (10 fps) and measured palate thickness was similar (p=NS) to that at the highest resolution (1.6×1.6×10.0 mm³). SNR in intensity–time plots through the soft palate was highest with 2.7×2.7×10.0 mm³ resolution (20 fps).

Conclusions

At 3 T, SSFP images are of a reliable quality, but 1.5 T bSSFP images are often better. For geometric measurements, temporal should be traded for spatial resolution (1.9×1.9×10.0 mm³, 10 fps). For assessment of motion, temporal should be prioritised over spatial resolution (2.7×2.7×10.0 mm³, 20 fps).

Advances in knowledge

Diagnostic quality real-time soft palate MRI is possible using clinical scanners and optimised protocols have been developed. 3 T SSFP imaging is reliable, but 1.5 T bSSFP often produces better images.Approximately 450 babies born in the UK every year have an orofacial cleft [1], the majority of which include the palate [2]. While a cleft palate is commonly repaired surgically at around 6 months [3], residual velopharyngeal insufficiencies require follow-up surgery in 15–50% of cases [4]. This residual defect results in an incomplete closure of the velopharyngeal port, which in turns leads to hypernasal speech. Assessment of velopharyngeal closure in speech therapy is commonly performed using X-ray videofluoroscopy or nasendoscopy [5,6]. While nasendoscopy is only minimally invasive, it may be uncomfortable and provides only an en face view of the velopharyngeal port. In contrast, X-ray videofluoroscopy is non-invasive and produces an image which is a projection of the target anatomy. Additional information may be obtained from projections at multiple angles [5,7], but anatomical structures may overlie each other. Furthermore, soft tissue contrast, such as that from the soft palate, is poor, although it may be improved using a barium contrast agent coating [8] at the expense of making the procedure more invasive and unpleasant. Arguably the greatest drawback of X-ray videofluoroscopy is the associated ionising radiation dose, which carries increased risk in paediatric patients [9].An increasing number of research studies have used MRI to image the soft palate [10-13] and upper vocal tract [14-17]. In contrast to X-ray videofluoroscopy and nasendoscopy, MRI provides tomographic images in any plane with flexible tissue contrast. As a result, MRI has been used to obtain images of the musculature of the palate at rest and during sustained phonation [10,18,19]. It has also been used to image the whole vocal tract at rest or during sustained phonation [20-27] and with a single mid-sagittal image dynamically during speech [13,15-17,28-35].For assessment of velopharyngeal closure, dynamic imaging with sufficient temporal resolution and simultaneous audio recording is required. Audio recording during imaging is complicated by the loud noise of the MRI scanner, and both the safety risk and image degradation caused by using an electronic microphone within the magnet. As a result, optical fibre-based equipment with noise cancellation algorithms must be used [36].In order to fully resolve soft palate motion, Narayanan et al [30] suggested that a minimum temporal resolution of 20 frames s⁻¹ (fps) is required. A similar conclusion was reached by Bae et al [13], based on measurements of soft palate motion extracted from X-ray videofluoroscopy. Using segmented MRI, Inoue et al [35] demonstrated that changes in the velar position that were evident at acquired frame rates of 33 fps were not observed at 8 fps. However, MRI is traditionally seen as a slow imaging modality and achieving sufficient temporal resolution at an acceptable spatial resolution is challenging. Furthermore, as the soft palate is bordered on both sides by air, the associated changes in magnetic susceptibility at the interfaces make images prone to related artefacts.Dynamic MRI of the vocal tract has been performed using both segmented [17,33,37] and real-time acquisitions [13,15,16,28,31,38]. Segmented acquisitions [39] acquire only a fraction of the k-space data required for each image during one repetition of the test phrase and, hence, require multiple identical repetitions. While these segmented techniques permit high temporal and spatial resolutions [35], they require reproducible production of the same phrase up to 256 times [34], leading to subject fatigue. Differences between repeats of up to 95 ms in the onset of speech following a trigger have also been demonstrated [36].In contrast to segmented techniques, real-time dynamic methods permit imaging of natural speech, but require extremely rapid acquisition and often advanced reconstruction methods. The turbo spin echo (TSE) zoom technique [40] has been used to perform real-time MRI of the vocal tract [29,31] and is available as a clinical tool. The zoom technique excites a reduced field of view in the phase encode direction, hence allowing a smaller acquisition matrix and shorter scan for a constant spatial resolution. While such spin echo-based techniques are less susceptible to magnetic field inhomogeneity related signal dropout artefacts than other sequences, the frame rates achieved with these sequences are limited to 6 fps [31]. Gradient echo-based techniques have also been used to achieve similar temporal resolution [12,41,42] in the upper vocal tract, but are often used at much higher frame rates in other MRI applications such as cardiac imaging [43,44]. A number of gradient echo sequence variants exist. Fast low-angle shot (FLASH) type sequences [45] spoil any remaining transverse magnetisation at the end of every sequence repetition (TR). In contrast, steady-state free-precession (SSFP) sequences are not spoiled [46] and the remaining transverse magnetisation is used in the next TR to improve the signal-to-noise ratio (SNR), but renders the images sensitive to signal loss in the presence of motion. Balanced SSFP (bSSFP) sequences include additional gradients to bring the transverse magnetisation completely back into phase at the end of every TR [47,48]. The result is that bSSFP sequences have high SNR and are less sensitive to motion than SSFP sequences, but are more sensitive to field inhomogeneities, which cause bands of signal dropout.Both TSE and the gradient echo techniques discussed here sample in a rectilinear or Cartesian fashion, where one line of k-space is sampled in each echo. However, for real-time speech imaging, the highest acquired frame rates have been achieved by sampling k-space along a spiral trajectory [15,16,30,49]. While spiral imaging is an efficient way to sample k-space and is motion-resilient, it is prone to artefacts, particularly blurring caused by magnetic field inhomogeneities and off-resonance protons (i.e. fat) [50]. Recently, one group successfully used spiral imaging with multiple saturation bands and an alternating echo time (TE) to achieve an acquired real-time frame rate of 22 fps [13,16]. The saturation bands were used to allow a small field of view to be imaged without aliasing artefacts. The alternating TE was used to generate dynamic field maps which were incorporated into the reconstruction to compensate for magnetic field inhomogeneities. However, such advanced acquisition and reconstruction techniques are only available in a small number of research centres.The aim of this work is to optimise and demonstrate high-temporal-resolution real-time sequences available on routine clinical MRI scanners for assessment of soft palate motion and velopharyngeal closure. Consequently, radial and spiral acquisitions were excluded and the work focuses on Cartesian gradient echo sequences with parallel imaging techniques. As more clinical MRI departments now have 3 T scanners, imaging was performed at both 1.5 and 3 T to enable comparisons. At each field strength, we optimised sequences and implemented four combinations of spatial and temporal resolution in six subjects with simultaneous audio recordings.     

The intravertebral cleft in benign vertebral compression fracture: the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI

We compared the diagnostic performance of non-enhanced MRI and fat-suppressed contrast-enhanced MRI (CEMRI) in diagnosing intravertebral clefts in benign vertebral compression fractures (VCFs). We retrospectively reviewed 99 consecutive patients who had undergone percutaneous vertebroplasty for VCFs. A cleft was defined as a signal void or hyperintense area on non-enhanced MRI (T₁ and T₂ weighted imaging) or as a hypointense area within a diffusely enhanced vertebra on CEMRI. A cleft was confirmed as a solid opacification on post-procedural radiographs. The interobserver reliability and MRI diagnostic performance were evaluated. The interobserver reliability of non-enhanced MRI was substantial (k _ 0.698) and the interobserver reliability of CEMRI was almost perfect (k _ 0.836). Post-procedural radiographs showed solid cleft opacification in 32 out of the 99 cases. The sensitivity and specificity of non-enhanced MRI were 0.72 and 0.82 (observer 1) and 0.63 and 0.87 (observer 2), respectively. The sensitivity and specificity of CEMRI were 0.94 and 0.63 (observer 1) and 0.85 and 0.60 (observer 2), respectively. The sensitivity of CEMRI was significantly higher than that of non-enhanced MRI, and the specificity of non-enhanced MRI was higher than that of CEMRI. CEMRI was highly reliable and sensitive, and non-enhanced MRI was specific for intravertebral clefts. Therefore, spine MRIs, including CEMRI, could provide useful information about intravertebral clefts before percutaneous vertebroplasty.Intravertebral clefts associated with vertebral compression fractures (VCFs) are radiographic signs representing cavities within fractured vertebrae and have long been considered pathognomonic for avascular necrosis of the spine (Kümmell’s sign) [1–3]. However, several investigators have observed that intravertebral clefts are common in patients with osteoporotic compression fractures [4–6]. Currently, clefts are thought to represent corticocancellous disruption in mobile osteoporotic fractures, rather than avascular necrotic disease [4, 6].Percutaneous vertebroplasty (PV) is an effective and minimally invasive procedure for the treatment of osteoporotic compression fractures [7, 8]. The advent of PV as the major treatment option for VCFs has prompted interest in intravertebral clefts occurring in benign VCFs. Recent studies have suggested that the clinical outcomes and complications associated with PV are influenced by the presence of clefts [4, 9–13]. Thus, radiological detection of clefts is indispensable for managing patients with VCFs.Spine MRI is commonly used for the evaluation of acute VCFs. MRI is useful in distinguishing malignancy from acute osteoporotic VCFs [14, 15] and is effective in demonstrating bone marrow oedema associated with acute compression fractures, which is one of the indications for performing PV [14, 16]. The MRI findings associated with intravertebral clefts have been well described [3–5]. However, there is controversy concerning the efficacy of MRI in diagnosing clefts. Specifically, the reliability and effectiveness of contrast-enhanced MRI (CEMRI), first assessed by Oka et al in 2005 [11], has not been properly evaluated. Such evaluation is important, given that CEMRI entails additional expense.To evaluate the efficacy of the CEMRI for the prediction of intravertebral clefts, we assessed the interobserver reliability and diagnostic performance of non-enhanced T₁ weighted and T₂ weighted MRI (T1WI and T2WI) and CEMRI in the identification of intravertebral clefts in VCFs. We then compared the diagnostic performance of CEMRI with that of non-enhanced MRI.     

MRI features of serous oligocystic adenoma of the pancreas: differentiation from mucinous cystic neoplasm of the pancreas

Objectives

The purpose of this study was to describe the MRI features of the benign pancreatic neoplasm serous oligocystic adenoma (SOA) that differ from those of mucinous cystic neoplasm (MCN), a neoplasm with the potential for malignant degeneration.

Methods

Seven patients with SOA (seven women; mean age 36.6 years) and eight patients with MCN (eight women: mean age 39.9 years) were included. Several imaging features were reviewed: mass size, location, shape, wall thickness, cyst configuration (Type I, unilocular; Type II, multiple clustered cyst; Type III, cyst with internal septation) and signal intensity of the lesion with heterogeneity.

Results

SOA lesions were smaller (3.4 cm) than those of MCN (9.3 cm) (p=0.023). The commonest lesion shape was lobulated (85.7%) for SOA, but oval (50.0%) or lobulated (37.5%) for MCN (p=0.015). The most common cyst configuration was Type II (85.7%) for SOA and Type III (75.0%) for MCN (p=0.008). Heterogeneity of each locule in T₁ weighted images was visible in all cases of MCN, but in no case for SOA (p=0.004).

Conclusion

SOA could be differentiated from MCN by identifying the imaging features of lobulated contour with multiple clustered cyst configurations and homogeneity of each locule in T₁ weighted MR images.Serous oligocystic adenoma (SOA) is a recently described rare, benign pancreatic neoplasm and a morphological variant of serous microcystic adenoma, because it contains six or fewer cysts and the cysts are large (>2 cm) [1,2]. Pathologically, SOA is a benign pancreatic neoplasm composed of a few relatively large cysts uniformly lined with glycogen-rich cuboidal epithelial cells [3]. According to the World Health Organization classification, SOA is a subgroup of pancreatic serous cystic tumours and the term SOA is a synonym for macrocystic serous cystadenoma [3,4].The CT and MRI features of SOA of the pancreas are documented [2]. On CT and MRI, SOA typically appears as a small unilocular or bilocular cyst (<5 cm) with a thin wall (<2 mm) that lacks mural nodules or calcifications [2]. Because the cystic spaces are >2 cm, SOA images can be mistaken for mucinous cystic neoplasm (MCN), pseudocyst or intraductal papillary mucinous tumour [2,5-7]. It is very difficult to differentiate SOA from MCN by clinical and radiological features [2,6,8,9]. SOA does not require resection unless it causes symptoms, but MCN should be resected because of a potential for malignant degeneration [5,7,8]. Endoscopic ultrasound and cyst fluid aspiration have a role in distinguishing mucinous and serous lesions, but it is an invasive procedure with a risk of complications such as pancreatitis [10]. Therefore, it is clinically valuable to determine characteristic imaging findings that can distinguish SOA from MCN.Recently, Kim et al [6] and Cohen-Scali et al [5] described characteristic CT findings that can be used to differentiate SOA from MCN. MRI can demonstrate septa within a lesion with greater sensitivity than CT; therefore, MRI provides a better evaluation of tissue characteristics than CT [1,11]. However, few studies have described the MRI features of SOA [1,2]. The purpose of this study was to describe the differences in the MRI features of SOA and MCN in the pancreas.     

Cardiac MR assessment of cardiac myxomas

Cardiac myxomas are the most common benign primary cardiac tumour to present in adulthood. While most patients present with symptoms of cardiac obstruction, embolic phenomena or constitutional impairment, up to a fifth of patients remain asymptomatic and are incidentally diagnosed on imaging. Although echocardiography is usually the initial imaging modality used to evaluate these patients, cardiac MRI (CMR) has emerged over the past decade as the primary imaging modality in the assessment of patients with cardiac tumours. The superior tissue characterization capability of CMR means that it is able to determine the nature of some tumours pre-operatively and performs well in differentiating myxomas from thrombus. We present a pictorial review highlighting the key CMR features of myxomas and show how these lesions can be differentiated from thrombus and other cardiac masses.Primary cardiac tumours are uncommon with a reported prevalence at autopsy of 0.002%.¹ The majority are benign, with myxomas accounting for almost 50% of all primary cardiac tumours.² Myxomas are more common in female patients, and while they can occur at any age, they usually present in adults between the fourth and seventh decades of life.^3,4 Most patients typically present with at least one manifestation of the classic triad of cardiac obstructive symptoms, embolic phenomena and constitutional symptoms, but 20% are identified in asymptomatic patients as an incidental imaging finding.³Echocardiography is usually the initial imaging modality used in the assessment of a suspected cardiac mass but remains rather operator dependent with a restricted field of view and can be particularly challenging in patients with large body habitus.^2,4,5 Cardiac MRI (CMR) enables accurate assessment of the location and functional impact of cardiac masses in any imaging plane without exposing patients to ionizing radiation.^2,5 In particular, CMR performs better than echocardiography at determining the nature of cardiac lesions and can differentiate myxomas from thrombus.^2,5 Given that most cardiac lesions are not easily amenable to catheter-directed biopsy, accurate imaging differentiation of cardiac myxomas from other types of cardiac masses is of vital importance in guiding further management.     

Comparison of mammography, sonography, MRI and clinical examination in patients with locally advanced or inflammatory breast cancer who underwent neoadjuvant chemotherapy

Objectives

The purpose of this study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced or inflammatory breast cancer. Each prediction method was compared with the gold standard of surgical pathology.

Methods

43 patients (age range, 25–62 years; mean age, 42.7 years) with locally advanced or inflammatory breast cancer who had been treated by neoadjuvant chemotherapy were enrolled prospectively. We compared the predicted residual tumour size and the predicted response on imaging and clinical examination with residual tumour size and response on pathology. Statistical analysis was performed using weighted kappa statistics and intraclass correlation coefficients (ICC).

Results

The ICC values between predicted tumour size and pathologically determined tumour size were 0.65 for clinical examination, 0.69 for mammography, 0.78 for sonography and 0.97 for MRI. Agreement between the response predictions at mid-treatment and the responses measured by pathology had kappa values of 0.28 for clinical examination, 0.32 for mammography, 0.46 for sonography and 0.68 for MRI. Agreement between the final response predictions and the responses measured by pathology had kappa values of 0.43 for clinical examination, 0.44 for mammography, 0.50 for sonography and 0.82 for MRI.

Conclusion

Predictions of response and residual tumour size made on MRI were better correlated with the assessments of response and residual tumour size made upon pathology than were predictions made on the basis of clinical examination, mammography or sonography. Thus, the evaluation of predicted response using MRI could provide a relatively sensitive early assessment of chemotherapy efficacy.The advantages of neoadjuvant chemotherapy are multiple and it has been used widely during the past few years [1]. Its primary role is to induce tumour shrinkage and permit breast-conserving surgery, primarily in patients with advanced breast cancer [2-4]. Neoadjuvant chemotherapy allows earlier treatment of micrometastatic disease and the study of biological markers that might predict tumour response [5]. The effectiveness of chemotherapeutic agents in treating both primary breast cancer and potential metastatic disease may be enhanced by the presence of tumour neovascularity. If chemotherapy is given before surgery, while tumour vascularity remains intact, the chemotherapeutic agents may be better able to reach the tumour and thus be more effective.Neoadjuvant chemotherapy of locally advanced breast cancer (LABC) has also been shown to improve the resectability rate, offering disease-free and overall survival rates that are at least equivalent to those offered by surgery alone [6,7]. Pathological complete response (pCR) is clinically significant because it is associated with improved long-term prognosis and decreased risk of recurrence [6,8]. Decisions regarding the continuation of current regimens and the appropriate type and timing of surgery depend on the radiological and clinical assessment of residual tumour size during neoadjuvant chemotherapy [9,10]. Until now, many studies have shown that physical examinations, mammography and sonography provide suboptimal evaluations of lesion extent that do not allow accurate assessments of pathological response or residual tumour size [5^,11-13]. In the case of LABC, physical examination, mammography or sonography may be suitable for detecting the larger lesions of non-responders, but they have limited sensitivity for responders with smaller residual lesions [14,15]. For mammography, calcifications may persist or even increase in patients who respond to neoadjuvant chemotherapy [14,16,17].Many previous studies have shown that MRI is the most reliable technique for evaluating residual disease after neoadjuvant chemotherapy, although initial reports described frequent false-negatives with smaller-volume disease [18-27]. Recent studies have increased the sensitivity of MRI, with increased resolution, reduced slice thickness and lower enhancement thresholds being used to minimise the underestimation of residual disease [15^,22-27]. It is still difficult, however, to distinguish residual scarring, necrosis and fibrosis from viable residual malignancy and to predict accurate response after neoadjuvant chemotherapy, especially in responders. Few published studies have described work with patients with inflammatory breast cancer who underwent neoadjuvant chemotherapy because the incidence of this disease is very low [28,29]. The purpose of our study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced and inflammatory breast cancer. We compared each prediction method with the gold standard of surgical pathology.     

Cerebral lesions of multiple sclerosis: is gadolinium always irreplaceable in assessing lesion activity?

PURPOSE

We aimed to identify imaging characteristics on conventional magnetic resonance imaging that could predict multiple sclerosis (MS) brain lesion activity without contrast media administration.

MATERIALS AND METHODS

Magnetic resonance data sets of forty-two patients with relapsing-remitting MS who presented symptoms or signs suggestive of new disease activity were retrospectively reviewed. We classified the MS lesions into three types according to different patterns present on T2-weighted images and evaluated their relationship with the contrast uptake. Evolving aspects of each type of lesion were observed in 18 patients during a follow-up period ranging from nine to 36 months.

RESULTS

On T2-weighted images, only the pattern consisting of a thin border of decreased intensity compared with the lesion’s center and perifocal edema (Type II) reached diagnostic accuracy in terms of its relationship with gadolinium enhancement (P = 0.006). The sensitivity was 0.461, and the specificity was 0.698. In contrast, enhancement was not significantly related to the pattern consisting of a lesion center that was homogeneously brighter than its periphery (Type I) or less-hyperintense T2 focal lesions with either homogeneous or inhomogeneous center (Type III) (P > 0.05 for both).

CONCLUSION

The assessment of MS lesion activity should include a careful evaluation of T2-weighted images in addition to contrast enhancement assessment. The presence of an accompanying peripheral thin rim of hypointensity on T2-weighted images related best with contrast enhancement and subsequent lesion activity and may represent an additional pattern for disease activity assessment when gadolinium examination is contraindicated or influenced by prior therapy.Multiple sclerosis (MS) is a chronic inflammatory disease characterized by demyelination and widespread tissue damage in the white and grey matter in the central nervous system (CNS) and spinal cord (1). MS has a very heterogeneous neurological presentation. In diagnosing MS, magnetic resonance imaging (MRI) studies with and without gadolinium contrast are required, according to McDonald 2005 (2) and the modified McDonald criteria 2010 (3), to provide information about the CNS involvement of demyelinating lesions. A decreased incidence of clinical relapse in MS is commonly used as a measure of therapeutic intervention efficacy. Despite their generalized use in clinical trials of relapsing-remitting and progressive multiple sclerosis, the current MRI measures add little if anything to the clinically relevant relapse and disability outcomes when used independently (4). At the present time, there is limited association between the lesions detected with conventional MRI and clinical status (5), with a low reported sensitivity to diffuse grey-matter and white matter disease (6, 7). Therefore, there is a sustained need for research to find better MRI markers of disease activity.It is generally believed that because acute MS lesions are associated with a transient breakdown of the blood-brain barrier (BBB), gadolinium contrast agents would produce enhancement of these lesions on T1-weighted images. Beginning with the earliest magnetic resonance studies of MS, it became clear that the correlation between enhanced lesions and clinical disease activity is modest at best (8). Nevertheless, contrast enhancement remains a sensitive method for detecting active MS lesions, with all the implications derived from its presence (from diagnosis to treatment trial monitoring). However, there are conditions under which the administration of gadolinium-based agents is prohibited (9). Additionally, contrast administration cannot help document disease activity following steroid treatment when variable degrees of enhancing lesions suppression occurs (10).Still, is the information offered by the administration of contrast really irreplaceable? Certainly, a less invasive and more cost-effective method is needed in clinical practice to assess MS lesion activity. Ideally, this assessment method would also work for patients in whom gadolinium agents cannot be used or are influenced by medication. Furthermore, the confidence intervals for correlations between contrast-enhanced lesions and MS relapses exclude the possibility that contrast enhanced lesions can be a good surrogate outcome for the occurrence MS relapses (11). Furthermore, when studies centered their analysis on the morphological characteristics of the conventional MRI lesions of MS (rim lesions and ring enhancement) and the patients’ clinical characteristics (12), only ring-enhancing lesions seemed to be associated with a worse prognosis.Therefore, the present study aimed to identify imaging characteristics that could predict lesion activity without the administration of contrast media by analyzing the morphology and signal patterns of brain MS lesions on T2-weighted images that are present in all routine MRI protocols for MS surveillance and correlating these results with the findings obtained from contrast-enhanced T1-weighted images.     

Intratendinous ganglion cyst of the semimembranosus tendon

Intratendinous ganglion cyst is a very rare lesion with an unknown aetiology that originates within the tendon. We encountered a case of 43-year-old woman who complained of a palpable, non-tender mass in the thigh with increasing swelling. An intratendinous ganglion cyst in the semimembranosus tendon of the lower extremity was diagnosed and located by ultrasound and MRI. Nine months after a surgical excision, there were recurrent ganglion cysts along the semimembranosus tendon. We describe this case with a review of the relevant literature.A ganglion cyst is a common tumour-like lesion arising from various soft tissues that is generated by mucoid degeneration of the joint capsule, tendon or tendon sheath [1]. It can occur in any part of the extremities including the hand, wrist and foot. However, an intratendinous ganglion cyst is an uncommon lesion that originates within the tendon substance itself and causes soft-tissue swelling [2, 3]. As reported previously, intratendinous ganglion cysts are difficult to diagnose clinically before surgery and to excise completely [4]. For the most part, symptoms are mild in patients with pain and nerve compression [1, 5]. Ultrasound (US) and MRI can differentiate a ganglion cyst from other soft-tissue tumours and tumour-like lesions, and provide excellent information on the location of an intratendinous lesion [1, 2, 6]. To our knowledge, this is the first case report of an intratendinous ganglion cyst arising from the semimembranosus tendon itself.     

Prognostic factors associated with a subchondral insufficiency fracture of the femoral head

Objective

The aim of this study was to identify the risk factors associated with the prognosis of a subchondral insufficiency fracture of the femoral head (SIF).

Methods

Between June 2002 and July 2009, 25 patients diagnosed with SIF were included in this study. Sequential radiographs were evaluated for the progression of collapse. Clinical profiles, including age, body mass index, follow-up period and Singh’s index, were documented. The morphological characteristics of the low-intensity band on T₁ weighted MRI were also examined with regards to four factors: band length, band thickness, the length of the weight-bearing portion and the band length ratio (defined as the proportion of the band length to the weight-bearing portion of the femoral head in the slice through the femoral head centre).

Results

Radiographically, a progression of collapse was observed in 15 of 25 (60.0%) patients. The band length in patients with progression of collapse [22.5 mm; 95% confidence interval (CI) 17.7, 27.3] was significantly larger than in patients without a progression of collapse (13.4 mm; 95% CI 7.6, 19.3; p<0.05). The band length ratio in patients with progression of collapse (59.8%; 95% CI 50.8, 68.9) was also significantly higher than in patients without a progression of collapse (40.9%; 95% CI 29.8, 52.0; p<0.05). No significant differences were present in the other values.

Conclusion

These results indicate that the band length and the band length ratio might be predictive for the progression of collapse in SIF.Subchondral insufficiency fractures of the femoral head (SIF) often occur in osteoporotic elderly patients [1-9]. Patients usually suffer from acute hip pain without any obvious antecedent trauma. Radiologically, a subchondral fracture is seen primarily in the superolateral portion of the femoral head [4,5,10]. T₁ weighted MRI reveal a very low-intensity band in the subchondral area of the femoral head, which tends to be irregular, disconnected and convex to the articular surface [2,4,5,7,9,11]. This low-intensity band in SIF was histologically proven to correspond with the fracture line and associated repair tissue [5,9]. Some cases of SIF resolve after conservative treatment [5,11-14]; other cases progress until collapse, thereby requiring surgical treatment [4-10,15]. The prognosis of SIF patients remains unclear.The current study investigated the risk factors that influence the prognosis of SIF based on the progression to collapse.     

Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases

Objectives

To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases.

Methods

72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T₁ and T₂ weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics.

Results

417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az) = 0.96, 0.97] than Gd-EOB-DTPA image set (Az = 0.86, 0.89) or DW-MRI image set (Az = 0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ = 0.81–0.88).

Conclusions

Combining DW-MRI with Gd-EOB-DTPA-enhanced T₁ weighted MRI significantly improved the detection of colorectal liver metastases.In patients with colorectal cancer, accurate assessment of the size, location and segmental distribution of liver metastases on a per-lesion basis is critical for treatment planning [1]. Accurate depiction of the size and distribution of liver metastases helps the selection of patients to undergo radical surgery [2,3] or minimally invasive therapy, such as radiofrequency ablation (RFA) [4], chemo-embolisation or radio-embolisation [5].The image contrast in diffusion-weighted MRI (DW-MRI) is based on differences in the mobility of water between tissues [6]. In tumour tissues, such as liver metastases, water mobility is often more impeded compared with normal parenchyma. Hence, metastases appear to have high signal intensity on DW-MRI, facilitating their detection.Compared with conventional T₂ weighted imaging, DW-MRI has been found to be superior for lesion detection in the liver [7-9]. When compared with contrast-enhanced MRI, DW-MRI had a higher diagnostic accuracy compared with superparamagnetic iron oxide (SPIO)-enhanced MRI [10] and similar diagnostic accuracy compared with gadolinium contrast-enhanced imaging [11] for detecting colorectal liver metastases. DW-MRI has also been found to be more sensitive than fluorodeoxyglucose (¹⁸FDG) positron emission tomography (PET) CT [12] for the same clinical indication. In another study, combining DW-MRI with T₁ weighted imaging after liver-specific contrast medium mangafodipir trisodium (MnDPDP) administration improved the diagnostic accuracy of colorectal liver metastases detection compared with either technique alone [13].Gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA; Eovist or Primovist; Bayer Schering Pharma, Berlin, Germany) is a relatively new hepatocyte-selective MR contrast medium that has been shown to be useful detecting liver metastases measuring <1 cm in diameter [14,15]. Delayed T₁ weighted imaging in the hepatocellular phase of contrast enhancement at 20 min to several hours after contrast administration demonstrates metastases as T₁ hypointense lesions against the avidly enhancing liver parenchyma.Both DW-MRI and Gd-EOB-DTPA-enhanced MRI are useful for the detection of liver metastases [7,8,14-16]. One study performed at 3 T compared the diagnostic performance of the two techniques for the identification of small (<2 cm) liver metastases [17]. Another study at 1.5 T independently compared the diagnostic performance of DW-MRI, dynamic phase MRI and hepatobiliary phase Gd-EOB-DTPA-enhanced MRI [18]. However, the possible incremental value of combining DW-MRI with Gd-EOB-DTPA-enhanced MRI for detecting colorectal metastases has not been reported. Hence, the aim of this study was to compare the diagnostic accuracy of Gd-EOB-DTPA-enhanced MRI, DW-MRI and a combination of both techniques for the detection of colorectal hepatic metastases.     

Correlation of the apparent diffusion coefficiency values on diffusion-weighted imaging with prognostic factors for breast cancer

Objective

The aim of this study was to correlate the apparent diffusion coefficient (ADC) value of breast cancer with prognostic factors.

Methods

335 patients with invasive ductal carcinoma not otherwise specified (IDC NOS) and ductal carcinoma in situ (DCIS) who underwent breast MRI with diffusion-weighted imaging were included in this study. ADC of breast cancer was calculated using two b factors (0 and 1000 s mm^–2). Mean ADCs of IDC NOS and DCIS were compared and evaluated. Among cases of IDC NOS, mean ADCs were compared with lymph node status, size and immunochemical prognostic factors using Student''s t-test. ADC was also correlated with histological grade using the Kruskal–Wallis test.

Results

Mean ADC of IDC NOS was significantly lower than that of DCIS (p<0.001). However, the mean ADC of histological grade of IDC NOS was not significantly different (p=0.564). Mean ADC of oestrogen receptor (ER)-positive or progesterone receptor (PR)-positive cancer was significantly lower than that of ER-negative or PR-negative cancer (p=0.003 vs p=0.032). Mean ADC of Ki-67 index-positive cancer was significantly lower than that of Ki-67 index-negative cancer (p=0.028). Mean ADC values of cancers with increased microvascular density (MVD) were significantly lower than those of cancer with no MVD increase (p=0.009). No correlations were observed between mean ADC value and human growth factor receptor 2 expression, tumour size and lymph node metastasis.

Conclusion

Low ADC value was correlated with positive expression of ER, PR, increased Ki-67 index, and increased MVD of breast cancer.Breast MRI is an established supplemental technique to mammography and ultrasonography for evaluation of suspicious breast lesions. Diffusion-weighted MRI (DWI) has recently been integrated into the standard breast MRI for discrimination of benign and malignant breast lesions obtained with dynamic contrast-enhanced MRI [1-13]. DWI is a non-invasive technique that represents the biological character of the mainly Brownian movement of protons in bulk water molecules in vivo. Apparent diffusion coefficient (ADC) values are quantified by measurement of mean diffusivity along three orthogonal directions, which are affected by cellularity of the tissue, fluid viscosity, membrane permeability and blood flow [7,9-11]. Microstructural characteristics, including water diffusion and blood microcirculations in capillary networks, were associated with ADC value. Decreased movement of molecules in highly cellular tissue showed correlation with a low ADC value [3,4]. Several studies of DWI of the breast have reported significantly lower ADC values in malignant tumours, compared with benign breast lesions and normal tissue [1-3,5-11,14]. Classic prognostic markers, including tumour size and grade, and lymph node status in patients with breast cancer, and molecular markers, including oestrogen receptor (ER), progesterone receptor (PR), Ki-67 index, human growth factor receptor 2 (HER2) protein and angiogenic molecular markers, have been reported [1,15,16]. Few studies have examined the correlation between ADC values and prognostic factors [1,8]. The purpose of this study is to compare ADC values of DWI of breast cancer with prognostic factors.     

MRI manifestations of soft-tissue haemangiomas and accompanying reactive bone changes

Objectives

Soft tissue haemangiomas are common benign vascular lesions that can be accompanied by reactive changes in the adjacent bone structure. This study aimed to discuss the MRI features of soft-tissue haemangiomas with an emphasis on changes in bone.

Methods

The radiographic and MRI findings of 23 patients (9 males, 14 females; mean age 25 years; age range 2–46 years) with soft-tissue haemangiomas were analysed retrospectively. MR images were evaluated for location of the lesion, size, configuration, signal features, contrast patterns, proximity to adjacent bone and changes in the accompanying bone. Excisional biopsy was performed in 15 patients.

Results

Radiographs demonstrated phleboliths in 8 patients (34%) and reactive bone changes in 4 (19%). On MRI, T₁ weighted images showed that most of the lesions were isointense or isohyperintense, as compared with muscle tissue; however, on T₂ weighted images all lesions appeared as hyperintense. Following intravenous gadolinium-diethylene triamine pentaacetic acid (DTPA) administration, homogeneous enhancement was observed in 3 lesions and heterogeneous enhancement was seen in 19. No enhancement was observed in one patient. Bone atrophy adjacent to the lesion was observed in four patients.

Conclusion

MRI is the most valuable means of diagnosing deep soft-tissue haemangiomas. Bone changes can accompany deeply situated haemangiomas; in four of our patients, we found atrophy of the bone adjacent to the lesion. To our knowledge, this is the first report in the literature regarding atrophy of the bone adjacent to a lesion.Soft-tissue haemangioma, a frequently encountered benign vascular lesion, accounts for 7% of all benign soft-tissue tumours [1-5]. Such lesions can be cutaneous, subcutaneous, intramuscular or synovial [1]. Intramuscular haemangioma is rare and responsible for 0.8–1.8% of all haemangiomas [3,5,6]. Superficial haemangiomas are diagnosed easily because they cause discolorations of the skin; imaging techniques are rarely needed [1]. However, deep lesions are difficult to diagnose clinically, because they do not cause discolorations and grow slowly; imaging techniques are required to discriminate these deep haemangiomas from malignant lesions [1,2,7]. Bone changes accompanying haemangioma have been reported previously in the literature and include cortical thickening, erosion, medullary sclerosis, trabecular coarsening and hypertrophy [1,8]. Here, we present the MRI manifestations of soft-tissue haemangiomas and reactive changes to the neighbouring bones. To the best of our knowledge, this is the first report of its kind in the English literature.     

Primary vaginal cancer: role of MRI in diagnosis,staging and treatment

Primary carcinoma of the vagina is rare, accounting for 1–3% of all gynaecological malignancies. MRI has an increasing role in diagnosis, staging, treatment and assessment of complications in gynaecologic malignancy. In this review, we illustrate the utility of MRI in patients with primary vaginal cancer and highlight key aspects of staging, treatment, recurrence and complications.The incidence of primary vaginal cancer increases with age, with approximately 50% of patients presenting at age greater than 70 years and 20% greater than 80 years.¹ Around 2890 patients are currently diagnosed with vaginal carcinoma in the USA each year, and almost 30% die of the disease.² The precursor for vaginal cancer, vaginal intraepithelial neoplasia (VAIN) and invasive vaginal cancer is strongly associated with human papillomavirus (HPV) infection (93%).^3,4 In situ and invasive vaginal cancer share many of the same risk factors as cervical cancer, such as tobacco use, younger age at coitarche, HPV and multiple sexual partners.^5–7 In fact, higher rates of vaginal cancer are observed in patients with a previous diagnosis of cervical cancer or cervical intraepithelial neoplasia.^7,8As is true for other gynaecologic malignancies, vaginal cancer diagnosis and staging rely primarily on clinical evaluation by the International Federation of Gynecology and Obstetrics (FIGO).⁹ Pelvic examination continues to be the most important tool for evaluating local extent of disease, but this method alone is limited in its ability to detect lymphadenopathy and the extent of tumour infiltration. Hence, FIGO encourages the use of imaging. Fluorine-18 fludeoxyglucose-positron emission tomography (¹⁸F-FDG-PET), a standard imaging tool for staging and follow-up in cervical cancer, can also be used for vaginal tumours, with improved sensitivity for nodal involvement compared to CT alone.¹⁰ In addition to staging for nodal and distant disease, CT [simulation with three dimensional (3D) conformations] is particularly useful for treatment planning and delivery of external beam radiation. MRI, with its excellent soft tissue resolution, is commonly used in gynaecologic malignancies and has been shown to be accurate in diagnosis, local staging and spread of disease in vaginal cancer.^11,12 While no formal studies are available for vaginal cancer, in cervical cancer MRI actually alters the stage in almost 30% of patients.^13–15Treatment planning in primary vaginal cancer is complex and requires a detailed understanding of the extent of disease. Because vaginal cancer is rare, treatment plans remain less well defined, often individualized and extrapolated from institutional experience and outcomes in cervical cancer.^1,16–19 There is an increasing trend towards organ preservation and treatment strategies based on combined external beam radiation and brachytherapy, often with concurrent chemotherapy,^14,20,21 surgery being reserved for those with in situ or very early-stage disease.²² Increasing utilization of MR may provide superior delineation of tumour volume, both for initial staging and follow-up, to allow for better treatment planning.²³     

Characterisation of breast papillary neoplasm on automated breast ultrasound

Intraductal papillary neoplasms of the breast form a wide spectrum of pathological changes with benign intraductal papilloma and papillary carcinoma. They can occur anywhere within the breast ductal system. This review illustrates some characteristic appearances of breast papillary neoplasms on coronal planes reconstructed by automatic breast volume scan. Such manifestations are not uncommon in papillary neoplasms, and familiarity will enable confident diagnosis.Papillary lesions of the breast are a heterogeneous group of breast lesions, including intraductal papilloma, atypical papilloma and intraductal papillary carcinoma [1,2]. Although the management of intraductal papillomas is varied, surgical excision is generally recommended as a precaution against the risk of a subsequent carcinoma [3,4]. Recently, some studies have suggested that patients with a tumour measuring <1.5 cm and an ultrasound Breast Imaging—Reporting and Data System (BI-RADS) category of 3 or 4a can be potentially selected for vacuum-assisted biopsy, but only if the tumour does not extend into the branching ducts [5,6]. Ueng et al [2] recommended that localised papillary lesions should be excised completely with a small rim of uninvolved breast tissue without any prior needle instrumentation if and when the papillary nature can be determined by imaging. Therefore, a careful imaging evaluation is necessary because it could help to identify the papillary neoplasm nature and select the high-risk lesions for proper treatment.Ultrasound has a greater sensitivity for detecting all papillary lesions than mammography [7]. Recently, automated breast ultrasound scanners have been developed, and the ultrasound volume data set of the whole breast can be acquired in a standard manner [8]. They have already shown potential for characterisation of breast tumours [9,10]. However, these studies did not detail the ultrasound features of intraductal papillary neoplasms on automated breast ultrasound. The reconstructed coronal views are also expected to provide more information and thus help to differentiate these lesions from other focal breast abnormalities.     

Embolisation of the right gastric artery in patients undergoing hepatic arterial infusion chemotherapy using two possible approach routes

We used a retrospective non-randomised study to investigate the clinical effect of selective embolisation of the right gastric artery before hepatic arterial infusion chemotherapy (HAIC) using a port-catheter system. We evaluated whether the hepatic artery or the left gastric artery is the better approach for selecting the right gastric artery. A total of 367 patients (244 men and 123 women; mean age, 64.1 years) with unresectable advanced liver cancer underwent percutaneous implantation of a port-catheter system. In 294 of these patients, right gastric arterial embolisation with microcoils was attempted before placement of the port-catheter system to prevent gastric mucosal lesions. Approach was either through the hepatic artery (175 patients) or through the left gastric artery (119 patients), with success rates in catheterising the right gastric artery of 78.3% and 77.3%, respectively. If the attempt was unsuccessful, the catheter was redirected to the alternative approach, which increased the final success rate to 96.3%. Only seven patients experienced gastroduodenal mucosal lesions acutely after HAIC, as revealed by endoscopy. Embolisation of the right gastric artery is a feasible procedure that can reduce the incidence of gastric mucosal lesions associated with HAIC. Approach through either the hepatic artery or the left gastric artery is equally acceptable.Long-term hepatic arterial infusion chemotherapy (HAIC) via an implanted port-catheter system is a treatment option for patients with unresectable advanced liver cancer [1, 2]. In the past, such catheter placement was done by surgical laparotomy under general anaesthesia [3–6], an invasive procedure. However, recent advances in interventional techniques allow the implantation of port-catheter systems percutaneously under local anaesthesia [7–14].A frequent complication is reactive gastric or duodenal mucosal lesions, which result from chemical irritation caused by infusion of chemotherapeutic agents into adjacent organs through arteries originating from the common hepatic artery [15–24]. One such complication is a gastric mucosal lesion caused by inflow of chemotherapeutic agents into the right gastric artery [15–24]. To prevent this complication, the efficacy of selectively embolising the right gastric artery with coils at the time of implantation of the port-catheter system has been noted [21, 25–27].In many cases, however, the right gastric artery is slender and angulated, with anatomical variations [26, 28–31]. Hence, it is occasionally difficult to insert a catheter selectively into the right gastric artery by antegrade catheterisation via the site of the hepatic artery. This is the approach most commonly used by interventional radiologists. Failure to embolise the right gastric artery can result [26]. As an alternative method, a retrograde approach to the right gastric artery via the left gastric artery has been introduced [32, 33].Because HAIC with an implanted port-catheter system is performed in a relatively large number of cases in our institution, we have many opportunities to embolise the right gastric artery using both approaches. The aim of the present retrospective non-randomised study, which included a large number of subjects, was to evaluate the usefulness of right gastric arterial embolisation and to determine whether the antegrade or retrograde approach is more useful.     

Radio-guided occult lesion localisation for breast lesions under computer-aided MRI guidance: the first experience and initial results

Objective

The purpose of this study was to present an alternative technique for the pre-operative localisation of solely MRI-detected suspicious breast lesions using a computer-assisted MRI-guided radio-guided occult lesion localisation (ROLL) technique.

Methods

Between January 2009 and June 2010, 25 females with a total of 25 suspicious breast lesions that could be detected only by MRI, and for whom breast surgery was planned, underwent the computer-assisted MRI-guided ROLL technique. A seven-channel biopsy breast array coil and computerised diagnostic workstation were used for the localisation procedure. Three-phase dynamic contrast-enhanced axial images were taken. After investigating the localisation co-ordinates with the help of intervention software on a workstation, an 18 G coaxial cannula was placed in the exact position determined. Following verification of the cannula position by additional axial scans, ^99mTc-labelled macroalbumin aggregate and MRI contrast material were injected. Post-procedure MRI scans were used to confirm the correct localisation.

Results

All the procedures were technically successful. The mean lesion size was 10.8 mm (range: 4–25 mm). The mean total magnet and the mean localisation times were 28.6 min (range: 18–46 min) and 13.1 min (range: 8–20 min), respectively. Grid and pillar methods were used for localisation in 24 procedures and 1 procedure, respectively. On histopathological examination, 6 malignant, 10 high-risk and 9 benign lesions were identified. All patients tolerated the procedure well. There were no major complications.

Conclusion

This is the first report documenting the application of MRI-guided ROLL. Based on our preliminary results, this technique is very efficient and seems to be a good alternative to wire localisation.MRI of the breast has now become an integral and necessary component of breast imaging practice [1]. It is a valuable tool with high sensitivity for the identification of breast cancer in high-risk patients, follow-up of patients with known breast cancer and in patients at a pre-operative stage in order to rule out any ipsilateral or contralateral disease [2-5]. It can detect suspicious breast lesions that are occult to clinical examination, mammography and ultrasonography [4,6,7]. It was reported that, although the addition of MRI to current evaluation (clinical, radiological and pathological) has no benefit on a reduction of operation rates, cost-effectiveness and quality of life, it has the potential to aid tumour localisation [8].An MRI-guided intervention is necessary to make a definitive histological diagnosis of such “solely” MRI-detected suspicious breast lesions. Histopathological assessment can be performed by MRI-guided wire localisation followed by surgical excision [6,9,10], or by alternative techniques to surgery such as MRI-guided percutaneous biopsy using fine needles [11], core needles [12,13] or vacuum-assisted biopsy devices [7,14]. For such a breast intervention to be clinically useful, factors such as safety, accuracy, availability, cost, patient preference for surgical biopsy and surgeon''s request should be considered. With fine or core needle, lesions measuring <1 cm may not always be accurately sampled, and vacuum biopsy would bring an extra cost burden if surgical biopsy is already planned.MRI-guided wire localisation is a well-known (and currently the most commonly utilised) technique. Several authors have reported success with this technique for surgical biopsy [6-10]. According to them, it can be performed quickly and safely with relatively simple methods and commercially available equipment. However, this technique harbours several limitations and poses potential challenges during and/or after its application, such as the necessity to perform surgery on the same day owing to the risk of wire migration and/or accordion effect [6], breast pain, and poor cosmetic outcome after surgery [15].Radio-guided occult lesion localisation (ROLL) has been documented as a more reliable and effective method than wire for the identification of non-palpable breast lesions [16,17]. Routine ROLL involves the injection of ^99mTc-labelled human serum albumin into the suspicious lesion under ultrasonography or mammography control within 24 h prior to surgery. Subsequently, surgical excision is performed with the help of a hand-held gamma probe [18].To the best of our knowledge, ROLL has never been reported as an adjunct for the pre-operative localisation of solely MRI-detected suspicious breast lesions. Thus, the purpose of this study was to introduce a new technique—computer-aided and MRI-guided ROLL—to present its technical aspects and document our initial results.     

Feasibility study on energy prediction of microwave ablation upon uterine adenomyosis and leiomyomas by MRI

Objective:

To evaluate the feasibility of energy prediction of percutaneous microwave ablation (PMWA) upon uterine leiomyomas and adenomyosis by MRI.

Methods:

63 patients (49 patients with 49 uterine leiomyomas and 14 patients with adenomyosis) who underwent ultrasound-guided PMWA treatment were studied during the period from June 2011 to December 2012. Before PMWA, contrast-enhanced MRI (ceMRI) was performed for all of the patients. Based on the signal intensity (SI) of T₂ weighted MRI, uterine leiomyomas were classified as hypointense, isointense and hyperintense. During ablation, the output energy of the microwave was set at 50 W, and T11a microwave antennas were used. ceMRI was performed within 7 days after PMWA treatment. Non-perfused volume and energy required per unit volume were analysed statistically.

Results:

When unit volume of lesions was ablated, uterine adenomyosis needed more energy than did uterine leiomyomas, and hyperintense uterine leiomyomas needed more energy than did hypointense pattern.

Conclusions:

MRI SI of uterine leiomyomas and uterine adenomyosis can be used to predict PMWA energy.

Advances in knowledge:

The conclusions indicate that MRI SI can be used to perform pre-treatment planning, which will make the treatment more precise.Uterine leiomyomas and adenomyosis are benign lesions that occur most commonly in females of childbearing age. Although many females with uterine leiomyomas and adenomyosis are asymptomatic, as many as 20–65% of them have symptoms^1,2 such as abnormal uterine bleeding, dysmenorrhoea, pelvic pressure, low abdominal pain and infertility. These symptoms often lead to reduced quality of life, as well as loss of work and increased medical costs.³ Hysterectomy has been the main mode of therapy for leiomyomas and adenomyosis. However, medical technology advancements have made less invasive treatment options available, such as uterine artery embolization (UAE),^4–6 high-intensity focused ultrasound (HIFU),^7–9 radiofrequency (RF)¹⁰ and percutaneous microwave ablation (PMWA).^11,12 PMWA is a minimally invasive technique for the treatment of uterine leiomyomas and adenomyosis by inducing tissue necrosis through heat. Previous reports^11,12 have indicated that PMWA provides a feasible, safe and reliable alternative for the treatment of uterine leiomyomas and adenomyosis. However, until now, the energy required per unit volume (EPV) of PMWA in uterine lesions has been unclear, which has limited the widespread use of PMWA therapy. In this study, we sought to investigate the relationship between the MRI signal intensity (SI) of uterine lesions and the EPV of PMWA to better predict PMWA energy before treatment and to make the PMWA procedures standardized.     

Focal nodular hyperplasia: characterisation at gadoxetic acid-enhanced MRI and diffusion-weighted MRI

Purpose:

The aim of this study was to assess the enhancement patterns of hepatic focal nodular hyperplasia (FNH) on gadoxetic acid-enhanced MRI and diffusion-weighted (DW) MRI.

Methods:

This retrospective study had institutional review board approval. Gadoxetic acid-enhanced and DW MR images were evaluated in 23 patients with 30 FNHs (26 histologically proven and 4 radiologically diagnosed). The lesion enhancement patterns of the hepatobiliary phase images were classified as heterogeneous or homogeneous signal intensity (SI), and as dominantly high/iso or low SI compared with those of adjacent liver parenchyma. Heterogeneous (any) SI lesions and homogeneous low SI lesions were categorised into the fibrosis group, whereas homogeneous high/iso SI lesions were categorised into the non-fibrosis group. Additionally, lesion SI on T₂ weighted images, DW images and apparent diffusion coefficient (ADC) values were compared between the two groups.

Results:

The lesions showed heterogeneous high/iso SI (n=16), heterogeneous low SI (n=5), homogeneous high/iso SI (n=7) or homogeneous low SI (n=2) at the hepatobiliary phase MR images. The fibrosis group lesions were more likely to show high SI on DW images and T₂ weighted images compared with those in the non-fibrosis group (p<0.05). ADC values tended to be lower in the fibrosis group than those in the non-fibrosis group without significance.

Conclusion:

FNH showed variable enhancement patterns on hepatobiliary phase images during gadoxetic acid-enhanced MRI. SI on DW and T₂ weighted images differed according to the fibrosis component contained in the lesion.

Advances in knowledge:

FNH shows a wide spectrum of imaging findings on gadoxetic acid-enhanced MRI and DW MRI.Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumour after haemangioma, and most frequently occurs in females of childbearing and middle age [1]. It is considered to result from a congenital vascular disorder leading to a hyperplastic response of the surrounding liver parenchyma and is histologically characterised by normal hepatocytes with malformed bile ducts [2,3]. It is generally accepted that FNH can be managed conservatively and most cases do not require surgery because of the lack of malignancy potential and low risk of complications such as rupture or haemorrhage [4,5]. Therefore, the goal of imaging is to make a confident diagnosis and to avoid a biopsy or even surgical resection.MRI is a well-established and widely used diagnostic modality for detecting and characterising focal hepatic lesions and generally allows a confident diagnosis of typical FNH [6–8]. Findings of typical FNH on conventional gadolinium-enhanced MRI are brisk arterial enhancement, iso or slightly low signal intensity (SI) on the portal and equilibrium phase, iso or slightly low SI on T₁ weighted images, iso or slightly high SI on T₂ weighted images, a central scar showing high SI on T₂ weighted images and delayed dynamic enhancement [6–9]. However, when atypical imaging features are present, such as atypical findings of a central scar, high SI on T₁ weighted images or washout during the portal or equilibrium phase, it is not easy to distinguish FNH from other hypervascular tumours, such as hepatocellular adenomas, hypervascular metastasis or fibrolamellar hepatocellular carcinomas [6,9]. Indeed, according to a study by Bieze et al [6], characterisation of FNH and hepatocellular adenoma on standard MRI is inconclusive in 40% of lesions.Gadoxetic acid (Primovist®; Bayer-Schering Pharma, Berlin, Germany) is a new recently approved hepatobiliary gadolinium-based contrast agent. It has dual pharmacokinetic actions that combine extracellular properties for dynamic phase imaging with high hepatocyte-specific uptake and biliary excretion for delayed hepatobiliary phase imaging [10,11]. Many reports have concluded that FNHs show liver-specific enhancement and appear as iso or high SI on hepatobiliary phase imaging, and this enhancement pattern is a new additional criterion for diagnosing FNH, particularly in comparison with hepatocellular adenoma [6,10–15]. However, even though the major enhancement features of FNH are iso or high SI on hepatobiliary phase imaging, the portion of the central stellate scar or radiating fibrous septa of FNH demonstrates low SI owing to a lack of functioning hepatocytes. We postulate that the overall SI of FNH lesions during hepatobiliary phase imaging is dependent on their proportions of cellular and fibrous components.Diffusion-weighted (DW) imaging is useful for the detection and characterisation of hepatic focal lesions [16–18]. In theory, DW imaging measures the random motion of water molecules in biological tissues and reflects tissue properties, such as the size of the extracellular space, viscosity and cellularity [18–20]. According to prior hepatic fibrosis evaluations using DW imaging, lower apparent diffusion coefficient (ADC) values are observed in cirrhotic liver compared with normal liver tissue, which may be owing to restricted diffusion from extracellular fibrosis [21–25]. Despite the fact that FNH is benign, some lesions show diffusion restrictions, probably owing to their high cellularity [26–28], and fibrosis components contained in FNH lesions should influence the degree of diffusion restriction.The purpose of this study was to classify FNH lesions according to their enhancement pattern on hepatobiliary phase imaging and to assess the findings on DW and T₂ weighted imaging of the lesions with regard to those on hepatobiliary phase imaging.     

Subcutaneous panniculitis-like T-cell lymphoma with breast involvement: functional and morphological imaging findings

Panniculitis-like T-cell lymphoma is a very uncommon subtype of cutaneous T-cell lymphomas. In this case report, we describe the morphological (CT and MRI) and functional (¹⁸F-FDG-PET and bone scan) imaging findings in a 35-year-old patient who suffered from slowly progressing multiple subcutaneous lesions caused by this rare disease.According to the World Health Organization–European Organization for Research and Treatment of Cancer (WHO–EORTC) classification, subcutaneous panniculitis-like T-cell lymphomas (SPTCLs) belong to the group of cutaneous T-cell and natural killer (NK)-cell lymphomas [1]. Less than 1% of all non-Hodgkin lymphomas (NHLs) are SPTCLs. Recent studies differentiate distinct subtypes of SPTCL each with a different prognosis [2]. Only a few reports describe the imaging of primary cutaneous T-cell lymphomas [3–8], even fewer with the imaging of subcutaneous involvement in SPTCLs [4, 9–11]. In this case report, we describe panniculitis-like T-cell lymphoma as a very rare cause of unclear subcutaneous soft-tissue indurations. We detail the morphological and functional CT, MRI, ¹⁸F-FDG-PET and bone scan findings relating to multiple panniculitic lesions in a 35-year-old female patient suffering from this uncommon subgroup of lymphoma.     

Pancreatic ductal adenocarcinoma with intratumoral cystic lesions on MRI: correlation with histopathological findings

The purpose of this study was to evaluate intratumoral cystic lesions of pancreatic ductal adenocarcinoma (PDAC) depicted on MRI, and to correlate these cystic lesions with their histopathological findings. This study included 12 patients (7 males and 5 females; mean age, 59 years) with intratumoral cystic lesions of PDAC detected on a retrospective MRI review. We reviewed the histopathological findings of the cystic lesions within PDACs and analysed the MRI findings, focusing on the appearance of the intratumoral cystic lesions, i.e. the size, number, margin and intratumoral location, and on the ancillary findings of PDAC, i.e. peripancreatic infiltration, upstream pancreatic duct dilatation and distal parenchymal atrophy. Intratumoral cystic lesions were classified as neoplastic mucin cysts (n = 7, 58%) or cystic necrosis (n = 5, 42%) according to the histopathological findings; they ranged in greatest dimension from 0.5 cm to 3.4 cm (mean, 1.7 cm). Seven patients had only one cystic lesion each, while the remaining five had multiple cystic lesions. Most of the neoplastic mucin cysts had smooth margins (n = 6, 86%) and eccentric locations (n = 6), whereas most cystic necroses had irregular margins (n = 4, 80%) and centric locations (n = 4). The most common ancillary findings of PDAC were peripancreatic infiltration, distal pancreatic atrophy and upstream pancreatic duct dilatation (92%, 75% and 58%, respectively). The intratumoral cystic lesions of PDACs on MRI were classified as either neoplastic mucin cysts with smooth margins and eccentric locations or cystic necroses with irregular margins and centric locations.Pancreatic cancer is the fifth leading cause of cancer-related death in both men and women and is responsible for 5% of all cancer-related deaths in the United States [1]. Despite the advances in surgical techniques, as well as the major improvements in chemotherapy and radiotherapy protocols, the prognosis of pancreatic ductal adenocarcinoma (PDAC) usually implies a 1-year survival rate of <20% and a 5-year survival rate of <5% [2].PDAC typically presents as an irregular solid tumour with a scirrhous character resulting from a prominent desmoplastic reaction. However, recent studies have shown that PDAC may be accompanied by cystic changes within or adjacent to the mass, and that the incidence of PDAC with cystic changes ranges from <1% to 8% [3, 4]. Radiologists should be familiar with PDACs with cystic changes as they may resemble more common cystic pancreatic lesions, such as pseudocysts, intraductal papillary mucinous neoplasms (IPMNs), solid pseudopapillary tumours and non-functioning islet cell tumours, all of which are managed differently and usually have better patient survival rates [5–7].Many studies have discussed the radiological appearance of PDAC accompanied by cystic lesions [6–11]. Most of these studies have discussed pseudocysts or retention cysts depicted adjacent to the PDAC or in the extrapancreatic area in the clinical setting of pancreatitis [8–11], whereas only a few studies have discussed intratumoral cystic lesions, such as cystic necroses, in larger ordinary PDACs [6, 7]. Some case reports have described the intratumoral cystic changes of PDAC variants, i.e. adenosquamous carcinoma [12], mucinous adenocarcinoma (colloid or mucinous non-cystic carcinoma) [13], osteoclast-like giant cell carcinoma [14] and pleomorphic giant cell carcinoma [15]. To the best of our knowledge, there have been no radiological reports regarding the intratumoral cystic lesions of ordinary PDAC. Compared with CT, MRI has the advantage of being able to detect cystic changes within pancreatic masses and to provide more accurate morphological detail on these changes [16]. Therefore, the aims of this study were to evaluate intratumoral cystic lesions of ordinary PDAC detected on MRI and to correlate the cystic lesions with their histopathological findings.     

Contrast-enhanced MRI of the subdeltoid,subacromial bursa in painful and painless rotator cuff tears

Objective

Although shoulder pain is often associated with rotator cuff tears, many tears are asymptomatic and are not the cause of the patient''s pain. This may explain the persistence of symptoms in some patients despite technically successful rotator cuff repair. It has been proposed that rotator cuff tears cause pain through subdeltoid/subacromial bursal inflammation. The aim of this study was to determine whether bursal inflammation seen on MRI is associated with pain in patients with rotator cuff tears of the shoulder.

Methods

The shoulders of 255 patients were screened with ultrasound. 33 full-thickness rotator cuff tears (18 with shoulder pain and 15 without pain) were identified and subsequently studied using contrast-enhanced MRI of the shoulder. Enhancement of the subacromial bursa was scored independently by two musculoskeletal radiologists. Logistic regression was used to determine whether bursal enhancement was independently associated with pain.

Results

There was a significant association between pain and age, with greater likelihood of pain in younger patients. Bursal enhancement was common in both painful and painless tears. No statistically significant link between pain and bursal enhancement was seen, even after accounting for age.

Conclusion

Although enhancement of the subdeltoid/subacromial bursa was common, no evidence was found to support the hypothesis that bursal enhancement is associated with pain in rotator cuff tears. It is therefore unlikely to determine reliably which patients would benefit from rotator cuff repair.

Advances in knowledge

Bursal enhancement and thickening does not reliably correlate with symptoms or presence of rotator cuff tear.Rotator cuff tears are a common cause of pain in the shoulder. Surgical repair is an effective treatment, but a significant proportion of patients (5–12.5%) fail to achieve a satisfactory outcome [1-4]. Long-term outcome of surgery correlates poorly with the integrity of the cuff repair [5-7] and persistence of pain is a major factor [1]. In some cases, this may be because the shoulder pain is not due to rotator cuff damage at all [8]. Other painful shoulder pathologies are common, particularly in the elderly, including glenohumeral and acromioclavicular arthritis [9], and bone marrow oedema [10]. Asymptomatic rotator cuff tears are common, with increasing incidence with age and a reported prevalence of up to 80% in subjects aged over 80 years [11]. A significant proportion of these are full-thickness tears with one study reporting full-thickness tears in 28% of people over the age of 60 [12]. Rotator cuff tears may remain asymptomatic despite their large size [13] and, although the size of tears often increases, symptoms may develop or resolve with conservative treatment [14-16]. As yet there is no clear consensus regarding the indications for rotator cuff surgery [17,18]. A technique to determine whether a known rotator cuff tear is responsible for an individual patient''s pain would therefore be of great clinical value in developing patient management plans. While MRI has been shown to be accurate for detecting rotator cuff tears [19,20], there is no convincing evidence to date that it can be used to determine whether a full-thickness tear is symptomatic [12,21].The mechanism by which rotator cuff tears cause pain is poorly understood. Tears are associated with histological inflammation of the subdeltoid/subacromial bursa and this has recently been proposed as a cause of pain [22]. Synovial inflammation in the bursa in symptomatic rotator cuff tears could potentially be detected by the associated enhancement in the inflamed bursa seen on MRI after the administration of intravenous contrast agent, in the same way that synovial volume in joints in inflammatory arthritis has been shown to correlate with histological measures of inflammation [23]. The aim of this study was to use contrast-enhanced MRI to assess subacromial bursitis in patients with painful and painless rotator cuff tears in order to test the hypothesis that synovial enhancement at the subacromial bursa is greater in patients with shoulder pain.