Detection and classification of different liver lesions: Comparison of Gd-EOB-DTPA-enhanced MRI versus multiphasic spiral CT in a clinical single centre investigation

Objective

To compare the diagnostic efficacy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) vs. multidetector computed tomography (MDCT) for the detection and classification of focal liver lesions, differentiated also for lesion entity and size; a separate analysis of pre- and postcontrast images as well as T2-weighted MRI sequences of focal and exclusively solid lesions was integrated.

Methods

Twenty-nine patients with 130 focal liver lesions underwent MDCT (64-detector-row; contrast medium iopromide; native, arterial, portalvenous, venous phase) and MRI (1.5-T; dynamic and tissue-specific phase 20 min after application of Gd-EOB-DTPA). Hepatic lesions were verified against a standard of reference (SOR). CT and MR images were independently analysed by four blinded radiologists on an ordinal 6-point-scale, determining lesion classification and diagnostic confidence.

Results

Among 130 lesions, 68 were classified as malignant and 62 as benign by SOR. The detection of malignant and benign lesions differed significantly between combined and postcontrast MRI vs. MDCT; overall detection rate was 91.5% for combined MRI and 80.4% for combined MDCT (p < 0.05). Considering all four readers together, combined MDCT achieved sensitivity of 66.2%, specificity of 79.0%, and diagnostic accuracy of 72.3%; combined MRI reached superior diagnostic efficacy: sensitivity 86.8%, specificity 94.4%, accuracy 90.4% (p < 0.05). Differentiated for lesion size, in particular lesions <20 mm revealed diagnostic benefit by MRI. Postcontrast MRI also achieved higher overall sensitivity, specificity, and accuracy compared to postcontrast MDCT for focal and exclusively solid liver lesions (p < 0.05).

Conclusion

Combined and postcontrast Gd-EOB-DTPA-enhanced MRI provided significantly higher overall detection rate and diagnostic accuracy, including low inter-observer variability, compared to MDCT in a single centre study.     

Diffusion tensor tractography as a supplementary tool to conventional MRI for evaluating patients with myelopathy

Purpose

The aim of this study was to assess the clinical utility of DTI including apparent diffusion coefficient (ADC), fractional anisotropy (FA), in patients with symptoms of spinal cord myelopathy.

Patients and methods

Fifteen subjects with clinical symptoms of acute (n = 3) or slowly progressive (n = 12) spinal cord myelopathy and 11 healthy volunteers were prospectively selected. They all underwent magnetic resonance imaging of the spine at 3.0 T machine. In addition to conventional MRI, DTI was performed; maps of the apparent diffusion coefficient and of fractional anisotropy were reconstructed. Diffusion tensor tractography was used to visualize the morphological features of normal and impaired white matter at the level of the pathological lesions in the spinal cord. The patients were divided into two groups according to the signal intensity on T2WI (group A with no change in signal intensity and group B with high signal intensity).

Results

There were no statistically significant differences in the apparent diffusion coefficient and fractional anisotropy values between the different spinal cord segments of the normal subjects. All of the patients in group B had increased apparent diffusion coefficient values and decreased fractional anisotropy values at the lesion level compared to the normal controls. However, there were no statistically significant diffusion index differences between group A patients and the normal controls.

Conclusion

Diffusion tensor imaging is a reliable method for the evaluation of the diffusion properties of normal and compressed spinal cords. Furthermore, this technique can be used as an important supplementary tool to conventional MRI for the quantification of fiber damage in spinal cord compression, thus has the potential to be of great utility for treatment planning and follow up.     

Multi-detector computed tomography imaging of blunt chest trauma

Background and purpose

Chest trauma is a significant cause of mortality and morbidity, especially in the younger population. The purpose of this study was to evaluate the role of multi-detector computed tomography (MDCT) in the assessment of patients with blunt chest trauma.

Patients and methods

A prospective study was conducted on thirty (30) patients with blunt chest trauma (21 males and 9 females, aged from 6 to 62 years) and 29 control patients presented with any trauma other than blunt chest trauma (23 males and 6 females, aged from 10 to 68 years) at the Emergency Department, Tanta University Hospital, from January 2013 to February 2014. Cases were subjected to clinical evaluation and radiological assessment of the chest using conventional chest X-ray (CXR) and multi-detector computed tomography.

Results

The most common mode of injury was motor vehicle accidents (56.7%). On MDCT scan, the frequency of chest injuries were; chest wall injuries (86.7%), pleural injuries (80%), parenchymal injuries (56.7%), mediastinal injuries (30%) and finally the dorsal spine injuries (16.7%). MDCT is more sensitive, specific, and accurate than CXR in the assessment of blunt chest trauma and management of patients.

Conclusion

MDCT is the modality of choice for rapid assessment of emergency chest trauma patients, when chest X-ray was inconclusive.     

Adventure race's injuries

Objective

To describe the distribution of frequency of the injuries during adventure competition.

Material and methods

Fifty-five participants who underwent to the second stage of the Caloi Adventure Camp competition answered to a questionnaire about their personal characteristics, training status and injuries.

Results

The age of the athletes was 32 ± 10 years old and the body mass index (BMI) 23.3 ± 2.2 kg/m². The most frequent injuries occurred during trekking (61%), followed by mountain bike (24%). Abrasions (36.7%) and cuts (24.5%) were the most frequent injuries mentioned. Tissue level lesions occurred in 61.2% of the episodes. The most frequent injuries were contusions (16.3%) at muscular level, and sprain (6.1%) and fracture (6.1%) at osteoarticular system. Related to the body structure, the lower limb was the most affected (49%), mainly ankle (14.3%) and knee (12.2%). In the upper limb (30.6%), arm and forearm were more affected with cuts and abrasions. Neck and trunk were responsible for 20.4% of the injuries. Cramps (31%) and tendinitis (11%) were also mentioned.

Conclusion

The data suggest that it is necessary to create one training approach including prevention and logistics for participants rescue and rapid attendance during the tournament.     

Disfunción del tendón tibial posterior: ¿qué otras estructuras están implicadas en el desarrollo del pie plano adquirido del adulto?

Objective

To evaluate the association of posterior tibial tendon dysfunction and lesions of diverse ankle structures diagnosed at MRI with radiologic signs of flat foot.

Material and methods

We retrospectively compared 29 patients that had posterior tibial tendon dysfunction (all 29 studied with MRI and 21 also studied with weight-bearing plain-film X-rays) with a control group of 28 patients randomly selected from among all patients who underwent MRI and weight-bearing plain-film X-rays for other ankle problems.In the MRI studies, we analyzed whether a calcaneal spur, talar beak, plantar fasciitis, calcaneal bone edema, Achilles’ tendinopathy, spring ligament injury, tarsal sinus disease, and tarsal coalition were present. In the weight-bearing plain-film X-rays, we analyzed the angle of Costa-Bertani and radiologic signs of flat foot. To analyze the differences between groups, we used Fisher's exact test for the MRI findings and for the presence of flat foot and analysis of variance for the angle of Costa-Bertani.

Results

Calcaneal spurs, talar beaks, tarsal sinus disease, and spring ligament injury were significantly more common in the group with posterior tibial tendon dysfunction (P<.05). Radiologic signs of flat foot and anomalous values for the angle of Costa-Bertani were also significantly more common in the group with posterior tibial tendon dysfunction (P<.001).

Conclusion

We corroborate the association between posterior tibial tendon dysfunction and lesions to the structures analyzed and radiologic signs of flat foot. Knowledge of this association can be useful in reaching an accurate diagnosis.     

MRI findings of spinal visceral larva migrans of Toxocara canis

Purpose

The purpose of this study is to investigate the MRI findings of visceral larva migrans (VLS) of Toxocara canis in spinal cord.

Materials and methods

We retrospectively reviewed spinal MRI findings in eight patients with serologically proven Toxocara canis between 2005 and 2008.We evaluated the location, length, extent and migration of the lesion, MR signal intensity (SI), enhancement pattern, and swelling of the spinal cord.We evaluated clinical features including presenting symptoms and signs and treatment response.

Results

Total 8 patients (M = 8; age range 36-79 years) were included. The lesions were located in the cervical or thoracic spinal cord in all patients. All lesions showed high SI and minimal or mild swelling of involved spinal cord on T2WI and focal nodular enhancement on posterior or posterolateral segment of spinal cord. The length of involved lesion was relatively short in most patients. There was a migration of lesion in one patient.In spite of albendazole or steroid treatment, neurological symptoms or signs were not significantly improved in all patients.

Conclusion

Although all lesions show non-specific imaging findings like non-tumorous myelopathy mimicking transverse myelitis, single lesion, focal nodular enhancement on posterior or posterolateral segment of spinal cord, relatively short segmental involvement and migration of lesion may be characteristic findings of spinal VLM of Toxocara canis. In addition, the reluctant response to the treatment may be characteristic of spinal VLM of Toxocara canis.     

Detection of occult vertebral fractures by quantitative assessment of bone marrow attenuation values at MDCT

Objectives

To determine a cut-off value of Hounsfield attenuation units (HU) at multidetector computed tomography (MDCT) for valid and reliable detection of bone marrow oedema (BME) related to occult vertebral fractures.

Methods

36 patients underwent both MDCT and Magnetic Resonance Imaging (MRI) for evaluation of vertebral fractures of the thoracolumbar spine and were included in this retrospective study. Two readers independently assessed HU values at MDCT in a total of 196 vertebrae. Reliability was assessed by intraclass correlation coefficient and Bland–Altman analysis. For each patient we determined the vertebra with the lowest HU value and calculated the HU-difference to each other vertebral body. HU-differences were subjected to receiver operating characteristic (ROC) curve analysis to determine the diagnostic accuracy for detection of BME as determined by MRI, which served as the reference standard. Results of HU-measurements were compared with standard visual evaluation of MDCT.

Results

HU measurements demonstrated a high interrater reliability (ICC = 0.984). ROC curve analysis (AUC = 0.978) exhibited an ideal cut-off value of 29.6 HU for detection of BME associated with vertebral fractures with an accuracy of 97.4% as compared to 93.4% accuracy of visual evaluation. Particularly, HU-measurements increased the sensitivity for detection of vertebral fractures from 78.0% to 92.7% due to the detection of 7 of 9 occult fractures that were missed by visual evaluation alone.

Conclusions

Assessing bone marrow density by HU measurements using the cut-off of 29.6 HU is a valid and reliable tool for detection of BME related to occult vertebral fractures in MDCT. The introduced technique may allow more accurate treatment decisions and may make further diagnostic work-up with MRI unnecessary.     

A comparative study of cone-beam CT and multidetector CT in the preoperative assessment of odontogenic cysts and tumors

Aim of the work

To compare the accuracy of cone beam CT (CBCT) and multidetector CT (MDCT) in the preoperative radiological assessment of odontogenic cysts and tumors.

Material and methods

This prospective study included 24 patients (13 males and 11 females) with primary untreated pathologically proven odontogenic cysts and tumors. Their ages ranged from 5–45 years. They underwent (CBCT) and (MDCT). All CBCT and MDCT images were reviewed for morphologic characteristics of the lesions, internal appearance, extension as well as effect on surrounding structures. All patients were scheduled for surgical treatment within one week after clinical and radiological evaluation. Using intra-operative findings as the gold standard, the accuracy of (CBCT) and (MDCT) for radiological assessment of odontogenic cyst and tumors was compared.

Results

Histopathologic examination established that of the 24 tumors; 10 were radicular cyst, five dentigerous cyst, three amelobalstoma, three odontogenic keratocyst, one buccal bifurcation cyst, one nasopalatine cyst, and one lateral periodontal cyst. Both CBCT and MDCT were identical in detecting location, borders and internal structure of examined lesions. Concerning linear measurements of the lesions, MDCT underestimated mean depth by 1.7 mm and CBCT underestimated it by 0.9 mm. MDCT underestimated the mean width by 0.9 mm, and CBCT underestimated it by 0.7 mm. MDCT overestimated the mean height by 1.7 mm and CBCT overestimated it by 1 mm. CBCT was superior than MDCT in detecting thinning and perforation of buccal cortical plate and displacement of teeth.

Conclusion

In the overall assessment of odontogenic cysts and tumors, CBCT was comparable with MDCT with no significant statistical difference (P < 0.05). However, CBCT was more accurate in linear measurements and identification of tooth displacement and buccal bone defect. It is an optimal radiological modality for preoperative radiological assessment of odontogenic tumors.     

The MRI finding of the nerve root sedimentation sign: Its clinical validity and operative relativity for patients with lumbar spinal stenosis

Background

Lumbar spinal stenosis (LSS) is increasingly being recognised as a cause of disabling low back and lower extremities pain in adult population. Advanced spinal imaging thought as confirmation tool for the diagnosis and as preoperative tool to delineate the extent and precise location of the pathology. Nerve roots normally sediment, due to gravity, to the dorsal part of the dural sac, which was known as negative sedimentation sign. If there is MRI finding of nerve roots in the ventral part of the dural sac the sedimentation sign is positive.

Objectives

To evaluate the presence of the MRI finding of positive sedimentation sign in patients clinically suspected to have lumbar spinal stenosis and to follow up operated cases to identify the absence of the radiological signs in the operated cases.

Material and methods

70 patients clinically suspected to have lumbar spinal stenosis evaluated by MRI lumbosacral spine in supine position. A panel of two radiologists reviewed radiological data. MRI features were agreed by both radiologists in 48 patients. Out of these 48 patients; 25 were operated upon for central decompressive laminectomy, partial medial facetectomy and foraminotomy with instrumented fusion and fixation if indicated. Visual analogue score (VAS) collectively preoperative and postoperative was compared and the walking distance postoperative was reported and follow up MRI studies were done one year after the operation.

Results

Operated patients’ mean age was 58.2 years; nineteen patients were operated upon for simple decompressive laminectomy for the affected levels. Walking distance preoperative range 100–700 metres, improved postoperative to be 1474.0 ± 601.1. VAS for pain preoperative was 9.28 ± 0.84, improved at 12 month follow up to be 0.84 ± 0.62. Postoperative MRI done to evaluate the cross sectional area (CSA) became more than 80 mm² in the absence of the sedimentation sign and was negative in 22 cases.

Conclusion

The MRI finding of positive sedimentation sign is a good positive sign to rule in lumbar spinal stenosis with high specificity and sensitivity; negative sedimentation sign can be used in postoperative follow up of decompression patients.     

Preoperative mapping of arterial spinal supply using 3.0-T MR angiography with an intravasal contrast medium and high-spatial-resolution steady-state

Introduction

Preoperative mapping of the arterial spinal supply prior to thoracoabdominal aortic aneurysm repair is highly relevant because of high risk for postoperative ischemic spinal cord injuries such as paraparesis or paraplegia.

Methods

Twenty-four consecutive patients prior to surgical thoracoabdominal aortic aneurysm repair were investigated. All patients underwent steady-state MR angiography (MRA) of the spinal vasculature with 3-T MRI. The sequence used was a steady-state coronary 3D FLASH with 0.7-mm isotropic voxels. MRA was performed using an intravasal contrast agent. Studies were evaluated by three readers including delineation of arterial spinal supply including both aortic origin and spinal canal entry by three readers.

Results

Identification and localization of the Adamkiewicz artery and its spinal canal entry was successful in all patients. Overall depiction of the vascular anatomy was graded as very good in 3 (12.5%), good in 14 (58.4%), sufficient in 5 (20.8%), and poor in 2 (8.3%) patients. Depiction of segmental artery aortic exit level was graded as good in 6 (25.0%), sufficient in 10 (41.7%), poor in 4 (16.7%) and not identifiable in 4 (16.7%) patients. Delineation of segmental artery entry level into the spinal canal was graded as very good in 4 (16.7%), good in 11 (45.8%), sufficient in 6 (25.0%), and poor in 3 (12.5%) patients.

Conclusions

The use of 3-T MRA with an intravascular contrast agent and steady-state enables AKA localization including its segmental arteries with regard to the level of aortic origin and spinal canal entry in most patients.     

Fractures of the thoracic spine in patients with minor trauma: Comparison of diagnostic accuracy and dose of biplane radiography and MDCT

Objectives

To investigate the accuracy of biplane radiography in the detection of fractures of the thoracic spine in patients with minor trauma using multidetector computed tomography (MDCT) as the reference and to compare the dose of both techniques.

Methods

107 consecutive trauma patients with suspected fractures of the thoracic spine on physical examination were included. All had undergone biplane radiography first, followed by a MDCT scan between October 2008 and October 2012. A fourfold table was used for the classification of the screening test results. Both the Chi-square test (χ²) and the mean dose-length product (DLP) were used to compare the diagnostic methods.

Results

MDCT revealed 77 fractures in 65/107 patients (60.7%). Biplane radiography was true positive in 32/107 patients (29.9%), false positive in 19/107 patients (17.8%), true negative in 23/107 (21.5%) and false negative in 33/107 patients (30.8%), showing a sensitivity of 49.2%, a specificity of 54.7%, a positive predictive value (PPV) of 62.7%, a negative predictive value (NPV) of 41.1%, and an accuracy of 51.4%. The presence of a fracture on biplane radiography was highly statistical significant, if this was simultaneously proven by MDCT (χ² = 7.6; p = 0.01). None of the fractures missed on biplane radiography was unstable. The mean DLP on biplane radiography was 14.5 mGy cm (range 1.9–97.8) and on MDCT 374.6 mGy cm (range 80.2–871).

Conclusions

The sensitivity and the specificity of biplane radiography in the diagnosis of fractures of the thoracic spine in patients with minor trauma are low. Considering the wide availability of MDCT that is usually necessary for taking significant therapeutic steps, the indication for biplane radiography should be very restrictive.     

Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

Objective

To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy.

Materials and methods

Twenty preoperative tri-phasic MDCT (4-64-row, Siemens) and dynamic contrast-enhanced MRI (1.5 T or 3.0 T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1-60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%.

Results

Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1 cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1 cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference (p < .001), particularly for the detection of small lesions (≤1 cm; p < .004). There was no significant difference between the two modalities in the detection of lesions > 1 cm.

Conclusion

For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.     

A systematic approach towards the objective evaluation of low-contrast performance in MDCT: Combination of a full-reference image fidelity metric and a software phantom

Objectives

To assess the feasibility of an objective approach for the evaluation of low-contrast detectability in multidetector computed-tomography (MDCT) by combining a virtual phantom containing simulated lesions with an image quality metric.

Materials and methods

A low-contrast phantom containing hypodense spheric lesions (−20 HU) was scanned on a 64-slice MDCT scanner at 4 different dose levels (25, 50, 100, 200 mAs). In addition, virtual round hypodense low-contrast lesions (20 HU object contrast) based on real CT data were inserted into the lesion-free section of the datasets. The sliding-thin-slab algorithm was applied to the image data with an increasing slice-thickness from 1 to 15 slices. For each dataset containing simulated lesions a lesion-free counterpart was reconstructed and post-processed in the same manner. The low-contrast performance of all datasets containing virtual lesions was determined using a full-reference image quality metric (modified multiscale structural similarity index, MS-SSIM*). The results were validated against a reader-study of the real lesions.

Results

For all dose levels and lesion sizes there was no statistically significant difference between the low-contrast performance as determined by the image quality metric when compared to the reader study (p < 0.05). The intraclass correlation coefficient was 0.72, 0.82, 0.90 and 0.84 for lesion diameters of 4 mm, 5 mm, 8 mm and 10 mm, respectively. The use of the sliding-thin-slab algorithm improves lesion detectability by a factor ranging from 1.15 to 2.69 when compared with the original axial slice (0.625 mm).

Conclusion

The combination of a virtual phantom and a full-reference image quality metric enables a systematic, automated and objective evaluation of low-contrast detectability in MDCT datasets and correlates well with the judgment of human readers.     

Are Modic changes related to outcomes in lumbar disc herniation patients treated with imaging-guided lumbar nerve root blocks?

Objective

To compare outcomes after imaging-guided transforaminal lumbar nerve root blocks in MRI confirmed symptomatic disc herniation patients with and without Modic changes (MC).

Methods

Consecutive adult patients with MRI confirmed symptomatic lumbar disc herniations and an imaging-guided lumbar nerve root block injection who returned an outcomes questionnaire are included. Numerical rating scale (NRS) pain data was collected prior to injection and 20–30 min after injection. NRS and overall improvement were assessed using the patient's global impression of change (PGIC) scale at 1 day, 1 week and 1 month post injection. The proportion of patients with and without MC on MRI as well as Modic I and Modic II was calculated. These groups were compared for clinically relevant ‘improvement’ using the Chi-squared test. Baseline and follow-up NRS scores were compared for the groups using the unpaired t-test.

Results

346 patients are included with MC present in 57%. A higher percentage of patients without MC reported ‘improvement’ and a higher percentage of patients with MC reported ‘worsening’ but this did not reach statistical significance. The numerical scores on the PGIC and NRS scales showed that patients with MC had significantly higher pain and worse overall improvement scores at 1 month (p = 0.048 and p = 0.03) and a significantly lower 1 month NRS change score (p = 0.04).

Conclusions

Patients with MRI confirmed symptomatic lumbar disc herniations and MC report significantly lower levels of pain reduction after a lumbar nerve root block compared to patients without MC.     

MRI imaging of posterior reversible encephalopathy syndrome associated with pregnancy

Purpose

Our purpose is to characterize MRI, and diffusion-weighted imaging (DWI) findings in pregnant patients who were identified clinically to have PRES. We study the conversion of reversible vasogenic edema to irreversible cytotoxic edema and predict the progression to infarction.

Patients and methods

Twenty two pregnant females, aged between 20 and 46 years with gestational age between 20 and 40 weeks of gestation and with neurological manifestations had undergone conventional MRI, diffusion weighted image study, and ADC map.

Results

Lesions were mainly affecting the parieto-occipital regions, symmetrical or slightly asymmetrical distribution of the lesions in both cerebral hemispheres was found in most cases. The MRI findings in all the twenty two patients were: abnormal low SI in T1 WI, abnormal high SI on T2 and FLAIR WI. In DWI, hyperintensity with hyperintensity in ADC map was seen in 15 patients, hyperintensity with hypointensity in ADC map in 4 patients, normotensive in DWI with hyperintensity in ADC map in 3 patients.

Conclusion

The diagnosis of PRES has important therapeutic and prognostic value. The use of diffusion-weighted imaging and ADC maps allows an earlier and clearer differentiation of cytotoxic and vasogenic edema, which can predict the development of infarction.     

Detection of osseous metastases of the spine: comparison of high resolution multi-detector-CT with MRI

Purpose

The aim of the study was to evaluate the diagnostic accuracy of multi-slice-computed tomography (MDCT) for the detection of vertebral metastases in comparison to magnetic resonance imaging (MRI).

Materials and methods

In a retrospective analysis, 639 vertebral bodies of 41 patients with various histologically confirmed primary malignancies were analysed. The MDCT-images were acquired on a 16/64-row-MDCT scanner (Siemens Somatom Sensation 16/64). MRI was performed on 1.5 T scanners (SIEMENS Symphony/Sonata). The MDCT- and MRI-images were evaluated separately by two experienced radiologists in a consensus reading. The combination of MDCT and MRI in an expert reading including follow-up examinations and/or histology as well as clinical data served as the gold standard.

Results

201/639 vertebral bodies were defined as metastatically affected by the gold standard. In MDCT 133/201 lesions, in MRI 198/201 lesions were detected. 68 vertebral bodies were false negative in MDCT, whereas 3 false negatives were found in MRI. 3 false positive results were obtained in MDCT, 5 in MRI. Sensitivity was significantly lower for MDCT (66.2%) than for MRI (98.5%) (p < 0.0001). Specificity was not significantly different for both methods (MDCT: 99.3%; MRI: 98.9%). The diagnostic accuracy resulted in 88.8% for MDCT and 98.7% for MRI.

Conclusion

Although 16/64-row-MDCT provides excellent image quality and a high spatial resolution in the assessment of bony structures, metastatic lesions without significant bone destruction may be missed. The diagnostic accuracy of MRI proved to be significantly superior to 16/64-row-MDCT for the detection of osseous metastases.     

Can unenhanced multiparametric MRI substitute gadolinium-enhanced MRI in the characterization of vertebral marrow infiltrative lesions?

Purpose

To assess the diagnostic effectiveness of unenhanced-multiparametric magnetic resonance imaging (mp MRI) as an alternative to gadolinium (Gad)-enhanced MRI in the characterization of vertebral marrow infiltrative lesions.

Patients and methods

A prospective evaluation of fifty-six patients with suspected or untreated vertebral metastases undergoing MRI of the spine at 1.5 T was carried out. Two groups of sequences were assigned and compared for the characterization of marrow infiltrative lesions: group [A] unenhanced-mp MRI (including T1-weighted, T2-weighted, short time inversion recovery (STIR), diffusion weighted imaging (DWI) and in/opposed phase sequences) and group [B] gadolinium-enhanced MRI (including T1-weighted, T2-weighted, STIR and T1-weighted fat-suppressed gadolinium-enhanced sequence). Qualitative and quantitative image analysis was performed and compared. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for both imaging techniques were calculated.

Results

There was no statistical significant difference between unenhanced-multiparametric MRI and gadolinium-enhanced MRI as regards their diagnostic performance in differentiating benign from malignant vertebral marrow infiltrative lesions (p > 0.05) with calculated sensitivity (94% vs. 97%), specificity (92% vs. 88%), positive predictive value (94% vs. 91%), negative predictive value (92% vs. 95%) and (93% vs. 93%) accuracy.

Conclusion

Unenhanced-multiparametric MRI is compatible with gadolinium-enhanced MRI in reliable characterization of marrow infiltrative lesions. The routine MRI protocol of cancer patients should be altered to accommodate the evolving MRI technology and cost effectively substitute the need for a gadolinium enhanced scan.     

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL): Assessment of the involved white matter tracts by MRI

Background and purpose

Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is a recently identified autosomal recessive disorder with early onset of symptoms and slowly progressive pyramidal, cerebellar and dorsal column dysfunction. LBSL is characterized by distinct white matter abnormalities and selective involvement of brainstem and spinal cord tracts. The purpose of this study is to assess the imaging features of the involved white matter tracts in cases of LBSL by MRI.

Patients and methods

We retrospectively reviewed the imaging features of the selectively involved white matter tracts in sixteen genetically proven cases of leukoencephalopathy with brainstem and spinal cord involvement and elevated brain lactate (LBSL). All patients presented with slowly progressive cerebellar sensory ataxia with spasticity and dorsal column dysfunction. MRI of the brain and spine using 1.5 T machine and proton magnetic resonance spectroscopy (¹H MRS) on the abnormal white matter were done to all patients. The MRI and MRS data sets were analyzed according to lesion location, extent, distribution and signal pattern as well as metabolite values and ratios in MRS. Laboratory examinations ruled out classic leukodystrophies.

Results

In all cases, MRI showed high signal intensity in T2-weighted and FLAIR images within the cerebral subcortical, periventricular and deep white matter, posterior limbs of internal capsules, centrum semiovale, medulla oblongata, intraparenchymal trajectory of trigeminal nerves and deep cerebellar white matter. In the spine, the signal intensity of the dorsal column and lateral cortico-spinal tracts were altered in all patients. The subcortical U fibers, globi pallidi, thalami, midbrain and transverse pontine fibers were spared in all cases. In 11 cases (68.8%), the signal changes were inhomogeneous and confluent whereas in 5 patients (31.2%), the signal abnormalities were spotty. MRI also showed variable signal abnormalities in the sensory and pyramidal tracts in addition to the brainstem and cerebellar connections. Proton MRS showed consistent elevation of the lactate within the abnormal white matter.

Conclusion

Distinct MRI findings in the form of selective affection of subcortical and deep white matter tracts of the brain (involving the posterior limb of internal capsules and sparing the subcortical U fibers), dorsal column and lateral cortico-spinal tracts of the spinal cord should lead to the diagnosis of LBSL supported by the presence of lactate peak in ¹H MRS. The disease can be confirmed by the analysis of the disease gene DARS2.     

Can 18F-FDG PET improve the evaluation of suspicious breast lesions on MRI?

Objective

To evaluate the impact of adding 18F-fluorine-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in the evaluation of suspicious breast lesions on magnetic resonance imaging (MRI).

Methods

Sixty patients with suspicious breast lesions on MRI were selected to perform a PET–CT in prone position, dedicated to the evaluation of the breasts. The areas with increased 18F-FDG concentration relative to normal parenchyma were considered positive on PET–CT. Fusion of PET and MRI images (PET–MRI) was performed on a dedicated workstation to better locate corresponding lesions, and its findings were compared with histological results.

Results

76 lesions were evaluated, including 64 mass lesions (84.2%) and 12 non-mass lesions (15.8%). Lesions’ mean diameter on MRI was 29.6 ± 19.2 mm (range 6–94 mm). PET–CT showed increased metabolically activity on 57 lesions (75.0%), with mean maximum SUV of 5.7 ± 5.0 (range 0.8–23.1). On histopathology, there were 17 (22.4%) benign and 59 (79.7%) malignant lesions. Considering all lesions, PET–MRI fusion provided 89.8% sensitivity, 76.5% specificity and 86.8% accuracy. Considering only mass lesions higher than 10 mm, PET–MRI fusion provided 95.8% sensitivity, 83.3% specificity and 93.3% accuracy.

Conclusion

The inclusion of 18F-FDG PET on the evaluation of suspicious breast lesions on MRI helped to differentiate benign from malignant breast lesions, especially for mass lesions with a diameter higher than 10 mm.     

Role of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) in differentiating between benign and malignant breast lesions

Objective

To assess the role of DWI and ADC in differentiating between benign and malignant breast lesions.

Materials and methods

51 patients (age range 24–66 years; mean age 48 years) were included in our study. MRI was done using bilateral fat-suppressed T2- weighted fast spin-echo, STIR, axial T1-weighted fast spin-echo. DWI series were acquired using echo planar imaging pulse sequences incorporated with diffusion gradients and finally dynamic contrast enhancement study was done.

Results

Sixty three lesions were detected in 51 patients included in our study. Twenty one lesions were malignant, three lesions were intermediate and twenty two lesions were fibroadenoma according to the final histopathological study and seventeen lesions were breast cysts. A total of 21 lesions showed lower ADC values than benign lesions and were in the range of 0.76–1.29 × 10⁻³ mm²/s and were diagnosed as malignant breast lesions. The sensitivity and specificity for DWI in the differentiating malignant from benign breast lesions were calculated and showed 95.4% and 97.5%, respectively.

Conclusion

DWI is easy to obtain in short scan time and easy to evaluate, and ADC values can differentiate between benign and malignant breast lesions with high sensitivity and specificity.