The challenge of segmental small bowel motility quantitation using MR enterography

Objective:

Analysis of “cine” MRI using segmental regions of interest (ROIs) has become increasingly popular for investigating bowel motility; however, variation in motility in healthy subjects both within and between scans remains poorly described.

Methods:

20 healthy individuals (mean age, 28 years; 14, males) underwent MR enterography to acquire dynamic motility scans in both breath hold (BH) and free breathing (FB) on 2 occasions. Motility data were quantitatively assessed by placing four ROIs per subject in different small bowel segments and applying two measures: (1) contractions per minute (CPM) and (2) Jacobian standard deviation (SD) motility score. Within-scan (between segment) variation was assessed using intraclass correlation (ICC), and repeatability was assessed using Bland–Altman limits of agreement (BA LoA).

Results:

Within-scan segmental variation: BH CPM and Jacobian SD metrics between the four segments demonstrated ICC R = 0.06, p = 0.100 and R = 0.20, p = 0.027 and in FB, the CPM and Jacobian SD metrics demonstrated ICC R = −0.26, p = 0.050 and R = 0.19, p = 0.030. Repeatability: BH CPM for matched segments ranged between 0 and 14 contractions with BA LoA of ±8.36 and Jacobian SD ranged between 0.09 and 0.51 with LoA of ±0.33. In FB data, CPM ranged between 0 and 10 contractions with BA LoA of ±7.25 and Jacobian SD ranged between 0.16 and 0.63 with LoA = ±0.28.

Conclusion:

The MRI-quantified small bowel motility in normal subjects demonstrates wide intersegmental variation and relatively poor repeatability over time.

Advances in knowledge:

This article presents baseline values for healthy individuals of within- and between-scan motility that are essential for understanding how this process changes in disease.Dynamic “cine” MRI acquired during MR enterography is increasingly utilized to assess bowel motility in a range of conditions, notably inflammatory bowel disease and enteric dysmotility syndromes.^1–4 Analysis of the data remains primarily subjective in clinical routine, but the ability to apply quantitative techniques makes this a potentially powerful methodology to explore gastrointestinal physiology in disease as well as an emerging application as a biomarker for drug efficacy.^5–7Despite the growing literature, a consensus has yet to be reached as to the best method of quantitatively analysing small bowel data and indeed a range of motility metrics are proposed.^2,3,8–12 The most commonly used metric is the change in luminal diameter at a fixed anatomical position through the time series. By tracking bowel diameter, a characteristic curve can be produced with the number of contractions expressed per minute (CPM) to give an intuitive and broadly accepted metric for small bowel motility (SBM).^{2–4,9,11,13–15} To date, several studies have reported a relationship between CPM and dysmotility in disease, either compared with a histopathological standard or “normal” reference bowel loops.^2–4,12 An array of additional metrics derived both from bowel diameter measures and more abstract processing techniques have further been implemented with varying degrees of effectiveness in disease and health.^{2,4,5,8,10,14,16}Although intuitively attractive, the robustness of assessing overall enteric motility using only an isolated loop of bowel has received relatively little attention to date irrespective of the precise metric applied. It is unclear how representative the selected bowel loops are of overall SBM and if normal motility intrinsically differs between bowel segments, for example, between the jejunum and ileum. Furthermore, the repeatability of single loop metrics, even in normal individuals, is not well described, knowledge of which is vital if segmental analysis is to be used to diagnose, guide treatment and monitor enteric pathology.The purpose of this study is to explore segmental variation in SBM in healthy volunteers measured using two commonly reported small bowel metrics [CPM and Jacobian standard deviation (SD)] looking at (1) within-scan motility variation between different segments and (2) between-scan variation (repeatability) across two time points.     

Dosimetric evaluation of compensator intensity modulation-based stereotactic body radiotherapy for Stage I non-small-cell lung cancer

Objective:

To evaluate the dosimetry of compensator intensity modulation-based stereotactic body radiotherapy (SBRT) [non-coplanar intensity-modulated radiotherapy (ncIMRT)], its use was compared with that of three-dimensional conformation-based SBRT, for patients with Stage I non-small-cell lung cancer (NSCLC).

Methods:

21 consecutive patients with Stage I NSCLC were treated with ncIMRT or SBRT at Tokyo Medical University. To compare the two techniques, ncIMRT and SBRT plans for each patient were generated, where the planning target volume (PTV) coverages were adjusted to be equivalent to each other. The prescribed dose was set as 75 Gy in 30 fractions. PTV coverage, conformity index, conformation number (CN) and homogeneity index (HI) were used to compare the two strategies.

Results:

There was no statistically significant difference between PTV coverage for the 100%, 95% and 90% dose levels in the SBRT plan and those in the ncIMRT plan. The CN values were 0.53 ± 0.13 in the SBRT plan and 0.72 ± 0.10 in the ncIMRT plan. These values were significantly better than those of the SBRT plan (p < 0.001). The HI in the ncIMRT plan was 1.04 ± 0.03%, which was also significantly better than that of SBRT.

Conclusion:

The ncIMRT plan provided superior conformity and reduced the doses to the lung for patients with Stage I NSCLC.

Advances in knowledge:

The delivery technique with compensator intensity modulation-based SBRT was evaluated. Concerning target motion, this is thought to be more robust and safer than SBRT for early-stage NSCLC.Population-based studies have shown that approximately half of patients with radically treatable Stage I to III non-small-cell lung cancer (NSCLC) have been diagnosed as Stage I.^1,2 Stereotactic body radiotherapy (SBRT) was considered to be a treatment option for patients with Stage I NSCLC who were unsuitable for surgery. In most studies, the SBRT outcomes were comparable with surgery in terms of local control and survival.^3,4 Therefore, the use of SBRT for patients with Stage I NSCLC has gradually increased in number.⁵Videtic et al⁶ first reported excellent local control for Stage I NSCLC when using SBRT based on intensity-modulated radiotherapy (IMRT). Recently, a new type of IMRT named volumetric modulated arc therapy (VMAT) has also been introduced into clinical use. However, the IMRT dose delivery obtained by moving multileaf collimators was not consistent for a moving target.^7–10 By contrast, IMRT using compensated filter was capable of providing constant beams to a moving target and was consistent in the delivered dose distribution.^8,11,12 Furthermore, adjustment of respiratory-induced tumour motion is difficult^13,14 when multileaf collimators were used. We think gated irradiation using IMRT-compensated filter is an ideal method for moving targets. However, when using a compensator intensity modulation-based SBRT [non-coplanar IMRT (ncIMRT)] plan, the dosimetric benefit remains unknown for Stage I NSCLC. Thus, we investigated the benefits of the dose distribution of the ncIMRT plan for Stage I NSCLC via a comparison of the dosimetric parameters.     

Diffusion-weighted imaging vs STIR turbo SE imaging: capability for quantitative differentiation of small-cell lung cancer from non-small-cell lung cancer

Objective:

To compare the capability of differentiation of small-cell lung cancer (SCLC) from non-SCLC (NSCLC) between diffusion-weighted imaging (DWI) and short tau inversion recovery (STIR) turbo spin-echo imaging.

Methods:

The institutional review board of Kobe University Hospital, Kobe, Japan, approved this study, and written informed consent was obtained from each patient. 49 patients with NSCLC (30 males and 19 females; mean age, 66.8 years) and 7 patients with SCLC (5 males and 2 females; mean age, 68.6 years) enrolled and underwent DWI and STIR. To quantitatively differentiate SCLC from NSCLC, apparent diffusion coefficient (ADC) values on DWI and contrast ratios (CRs) between cancer and muscle on STIR were evaluated. ADC values and CRs were then compared between the two cell types by Mann–Whitney''s U-tests, and the diagnostic performances were compared by McNemar''s test.

Results:

There were significant differences of mean ADC values (p < 0.001) and mean CRs (p = 0.003). With adopted threshold values, the specificity (85.7%) and accuracy (85.7%) of DWI were higher than those of STIR (specificity, 63.3%; p = 0.001 and accuracy, 66.1%; p = 0.001). In addition, the accuracy of combination of both indexes (94.6%; p = 0.04) could significantly improve as compared with DWI alone.

Conclusion:

DWI is more useful for the differentiation of SCLC from NSCLC than STIR, and their combination can significantly improve the accuracy in this setting.

Advances in knowledge:

Pulmonary MRI, including DWI and STIR, had a potential of the suggestion of the possibility as SCLC.Lung cancer is the most common cause of cancer-related death among both males and females worldwide.¹ Lung cancers are divided into non-small-cell cancer (NSCLC) and small-cell lung cancer (SCLC), and the differentiation between SCLC and NSCLC is important in clinical practice because their therapeutic strategies, clinical course and prognoses are different.² In general, SCLC is usually determined with extensive hilar and mediastinal lymphadenopathy,³ and these cancers are mainly treated by chemotherapy or chemoradiotherapy.^2,4On the other hand, 5–10% of patients with SCLC were diagnosed as having solitary pulmonary nodules.^5,6 In this situation, the assessments of distant metastases before treatment play an important role in deciding the treatment. At present, although there are some different reports for patients with NSCLC regarding the assessment of distant metastases before surgery,^7–9 it is important to assess the distant metastases of these patients with SCLC because SCLC is known for its rapid doubling time, high growth fraction and early development of metastatic disease.^10–12 If patients with SCLC are diagnosed at Stage I or possibly Stage II, clinicians consider their treatment as surgery and/or neoadjuvant chemotherapy.^13–15 Therefore, the differentiation between SCLC and NSCLC and the suggestion of the possibility of SCLC may be important in routine clinical practice. However, the differentiation of SCLC from NSCLC is difficult on CT and positron emission tomography (PET) or PET/CT,^5,6,16 and fiberoptic bronchoscopy and percutaneous biopsy are recommended, although their diagnostic sensitivities range from 67% to 100%.^17–19Recently, the image quality and diagnostic capability of chest MRI has improved because of the advancement of MR systems and sequences, and short tau inversion recovery (STIR) turbo spin-echo (SE) imaging and diffusion-weighted imaging (DWI) have been reported as useful in differentiating malignant nodules and lymph nodes from benign ones in several articles.^20–25 Meanwhile, the utilities of chest MRI, including STIR and DWI, have been reported,²⁶ and, in addition, meta-analysis report for pulmonary nodules by means of DWI have been published.²⁷ However, to the best of our knowledge, there have been only reports of chest DWI regarding the differentiation between SCLC and NSCLC,²² but no major studies have reported a direct comparison of the use of DWI and STIR in chest MRI for the assessment of differentiation between SCLC and NSCLC. We hypothesized that both DWI and STIR were useful MR sequences for differentiation of SCLC from NSCLC and their combination might improve the differentiation capabilities. The aim of this study was to evaluate the diagnostic performances of DWI and STIR for differentiating between SCLC and NSCLC.     

Femoral neck shaft angle width is associated with hip-fracture risk in males but not independently of femoral neck bone density

Objective:

To investigate the specificity of the neck shaft angle (NSA) to predict hip fracture in males.

Methods:

We consecutively studied 228 males without fracture and 38 with hip fracture. A further 49 males with spine fracture were studied to evaluate the specificity of NSA for hip-fracture prediction. Femoral neck (FN) bone mineral density (FN-BMD), NSA, hip axis length and FN diameter (FND) were measured in each subject by dual X-ray absorptiometry. Between-mean differences in the studied variables were tested by the unpaired t-test. The ability of NSA to predict hip fracture was tested by logistic regression.

Results:

Compared with controls, FN-BMD (p < 0.01) was significantly lower in both groups of males with fractures, whereas FND (p < 0.01) and NSA (p = 0.05) were higher only in the hip-fracture group. A significant inverse correlation (p < 0.01) was found between NSA and FN-BMD. By age-, height- and weight-corrected logistic regression, none of the tested geometric parameters, separately considered from FN-BMD, entered the best model to predict spine fracture, whereas NSA (p < 0.03) predicted hip fracture together with age (p < 0.001). When forced into the regression, FN-BMD (p < 0.001) became the only fracture predictor to enter the best model to predict both fracture types.

Conclusion:

NSA is associated with hip-fracture risk in males but is not independent of FN-BMD.

Advances in knowledge:

The lack of ability of NSA to predict hip fracture in males independent of FN-BMD should depend on its inverse correlation with FN-BMD by capturing, as the strongest fracture predictor, some of the effects of NSA on the hip fracture. Conversely, NSA in females does not correlate with FN-BMD but independently predicts hip fractures.Hip fracture is the worst osteoporotic fracture with regard to cost^1,2 and adverse consequences,^3,4 so its prevention by checking for the related fracture risk factors is an important goal. Although low bone mineral density (BMD) is generally recognized as the main risk factor for hip fracture,^5,6 there is growing evidence that other bone characteristics, such as proximal femur geometry (PFG) parameters, are implicated in determining the risk profile for hip fracture.^7,8 This evidence, however, mainly derives from studies carried out in females,^9–13 whereas contradictory results characterize studies carried out in males.^14–20 Authors'' opinions seem to vary widely about the ability of the neck shaft angle (NSA), one of the PFG factors, to predict osteoporotic hip fractures in males,^14–16,21 whereas its association with the risk of hip fracture in females^10,11,14,22 is generally accepted. Gender differences in the hip anatomy²³ have been put forward as a possible explanation for the different relationship of NSA with the hip-fracture risk between genders, whereas geographic and racial differences²⁴ among the examined male populations have been advocated as a possible cause of authors'' discrepancies on the relationship between NSA and the hip-fracture risk in males.This topic is therefore still under debate, and further studies are required to clarify the association of the NSA with hip-fracture risk in males. The authors of the current study contribute to this topic by studying the relationship between NSA and the hip fragility fracture in a sample of white Italian males.     

Obscure gastrointestinal bleeding: diagnostic performance of 64-section multiphase CT enterography and CT angiography compared with capsule endoscopy

Objective:

To compare the diagnostic capabilities between capsule endoscopy (CE) and multislice CT (MSCT) enterography in combination with MSCT angiography for assessment of obscure gastrointestinal bleeding (OGIB).

Methods:

A total of 127 patients with OGIB were looked at in this study. 82 patients (aged 42.7 ± 19.1 years; 34 males) were assigned to receive MSCT diagnosis and 67 patients to (aged 53.9 ± 16.2 years; 28 males) receive CE diagnosis. Among them, 22 patients (aged 54.1 ± 19.1 years; 12 males) received both examinations. Oral isotonic mannitol and intramuscular injection of anisodamine were performed; non-ionic contrast (iopromide, 370 mg I ml⁻¹) was intravenously administered; and then multiphase scanning was conducted at arterial, small intestinal and portal venous phases in MSCT. The results were compared with findings of reference standards including double balloon enteroscopy, digital subtraction angiography, intraoperative pathological examination and/or clinical diagnosis.

Results:

Administration of anisodamine markedly increased the satisfaction rate of bowel filling (94.67% vs 28.57%; p < 0.001) but not the diagnostic yield (p = 0.293) of MSCT. Compared with MSCT, CE showed an improved overall diagnostic yield (68.66% vs 47.56%; p = 0.010), which was also observed in overt bleeding patients (i.e. patients with continued passage of visible blood) (76.19% vs 51.02%; p = 0.013) and in patients aged younger than 40 years of age (85% vs 51.28%; p = 0.024). However, CE had similar positive rates to MSCT (p > 0.05). Among the 22 cases in whom both examinations were conducted, CE showed no significantly different diagnostic capability compared with MSCT (p = 0.4597).

Conclusion:

Both CE and MSCT are safe and effective diagnostic methods for OGIB.

Advances in knowledge:

CE is preferred for overt bleeding or patients aged younger than 40 years. The combined use of CE and MSCT is recommended in OGIB diagnosis.Obscure gastrointestinal bleeding (OGIB), which accounts for approximately 5% of all gastrointestinal haemorrhage cases,¹ is defined as persistent or recurring gastrointestinal bleeding without an obvious aetiology after gastroduodenoscopy and colonoscopy.^2,3 Based on the presence or absence of clinically evident bleeding, OGIB could be divided into occult (no visible blood) and overt (continued passage of visible blood, such as haematemesis, melaena or haematochezia) bleeding.^3,4 OGIB frequently occurs in the small bowel and is caused by small bowel diseases such as intestinal erosions, ulcers, vascular anomaly, gastrointestinal tumours and inflammatory bowel and parasitic diseases.^5,6Multiple diagnostic techniques have been developed to elucidate the causes of OGIB. Among them, two non-invasive technologies, capsule endoscopy (CE) and multislice CT (MSCT) markedly improved the ability to determine the causes of OGIB by allowing the visualization of the gastrointestinal tract.^2,3,6 CE is able to obtain direct visualization of mucosal surface of the entire small intestine.^4,7,8 However, capsule retention remains a major risk of CE diagnosis.^4,9–11 In addition, the visual field restriction limits the value of CE in diagnosis of umbilicate or extraluminal lesions, since the small bowel is difficult to evaluate owing to its large length and tortuous course.^4,10 Conversely, MSCT, including MSCT angiography (MSCTA), MSCT enteroclysis and MSCT enterography (MSCTE), has full capacity to depict the extraintestinal lesions, owing to the combination of the advantages of enteral volume challenge with the ability of cross-sectional imaging.^4,12 Yet, substantial patient radiation exposure is one of the major disadvantages of MSCT diagnosis.^3,13 Careful preparation is also needed before examination.¹⁴ Considering that both CE and MSCT have advantages and disadvantages, a limited number of published data have compared the two diagnostic tools in patients with OGIB.^4,6,15–17 However, most of these studies did not refer to MSCTA, and apparently different results were obtained owing to the advancement of the two technologies. Thus, an updated and comprehensive comparison is required.Hence, we compared the diagnostic capability of MSCTE in combination with MSCTA with CE in patients suffering from OGIB. In this study, MSCTE and MSCTA technologies performed with a 64-slice spiral CT scanner were combined by non-contrast-enhanced scanning after oral administration of a neutral enteric contrast material (isotonic mannitol, 2.5%) and the intramuscular injection of anisodamine to restrain enterocinesia, and the following multiphase scanning at arterial, small intestinal and portal venous phases followed the intravenous infusion of non-ionic iodinated contrast material (iopromide, 370 mg I ml⁻¹). In addition, the influences of the clinical bleeding pattern and age on the diagnostic capability were also investigated.     

Walking on thin ice! Identifying methamphetamine “drug mules” on digital plain radiography

Objective:

The purpose of this study was to retrospectively evaluate the sensitivity, specificity and accuracy of identifying methamphetamine (MA) internal payloads in “drug mules” by plain abdominal digital radiography (DR).

Methods:

The study consisted of 35 individuals suspected of internal MA drug containers. A total of 59 supine digital radiographs were collected. An overall calculation regarding the diagnostic accuracy for all “drug mules” and a specific evaluation concerning the radiological appearance of drug packs as well as the rate of clearance and complications in correlation with the reader''s experience were performed. The gold standard was the presence of secured drug packs in the faeces.

Results:

There were 16 true-positive “drug mules” identified. DR of all drug carriers for Group 1 (forensic imaging experienced readers, n = 2) exhibited a sensitivity of 100%, a mean specificity of 76.3%, positive predictive value (PPV) of 78.5%, negative predictive value (NPV) of 100% and a mean accuracy 87.2%. Group 2 (inexperienced readers, n = 3) showed a lower sensitivity (93.7%), a mean specificity of 86%, a PPV of 86.5%, an NPV of 94.1% and a mean accuracy of 89.5%. The interrater agreement within Group 1 was 0.72 and within Group 2 averaged to 0.79, indicating a fair to very good agreement.

Conclusion:

DR is a valuable screening tool in cases of MA body packers with huge internal payloads being associated with a high diagnostic insecurity. Diagnostic insecurity on plain films may be overcome by low-dose CT as a cross-sectional imaging modality and addressed by improved radiological education in reporting drug carriers on imaging.

Advances in knowledge:

Diagnostic signs (double-condom and halo signs) on digital plain radiography are specific in MA “drug mules”, although DR is associated with high diagnostic insecurity and underreports the total internal payload.For the past decade, significant worldwide manufacturing of amphetamine-type stimulants has been reported to the United Nations Office on Drugs and Crime, Vienna, Austria, with a predominance of methamphetamine (MA) and its derivatives, which are also known as “syabu” or “ice”, throughout East and South East Asia.¹ In this region, the use of this synthetic drug is more prevalent than that of cocaine or heroin, which are more common in relatively developed areas, such as Europe and the USA.² During the course of this development, an increase in the number of drug carriers being intercepted by law enforcement at the borders of Malaysia has been observed. Drug carriers or “drug mules” are generally referred to as a human harbouring internal illicit drug packet(s). Internal body concealment of illegal drugs is one of the methods used to smuggle this illicit drug across the border.^3,4 “Drug mules” are generally known as body packers.^5,6 However, for correct terminology, one should differentiate between the terms body packer, body pusher and body stuffer. A body packer swallows a large amount of specially prepared drug packets to smuggle the packets in their gastrointestinal tract across a national border.^5,6 A body pusher hides a few containers in easily accessible body cavities, such as the rectum or vagina. Body stuffers, including traffickers and users, ingest intentionally small amounts of loosely wrapped drug pellets (typically initially hidden in the mouth), usually immediately before an unexpected encounter with law enforcement.^5–10The generally accepted radiological examination is a plain abdominal radiograph in the supine projection.^4–6 This technique is widely available at a low cost and is a simple method of detecting drug-filled packets within the alimentary tract. Radiation exposure to the patient is relatively moderate. In the literature, the detection rate for drug-filled packets is highly variable, and sensitivities from 58.3% to 90% have been reported.^4,5,11 Hence, plain abdominal radiography is a flawed screening method for identifying “drug mules”. Examining the bowel for foreign bodies, such as drug containers with variable sizes and radiodensities, is problematic, even for an experienced radiologist because the drug-filled packets may have an appearance similar to that of stool and gas and may be superimposed. Specific appearances described in the literature, such as the “double-condom”, “halo” and “rosette” signs, may be diagnostic for drug packages but are not necessarily so.^{4–6,11–13} Other modalities employed worldwide for the identification of body packers include CT, ultrasound, MRI and low-dose linear slit digital radiography (LSDR or LODOX®; Lodox Systems, Johannesburg, South Africa).^4,5,14–18Recent research has mainly concentrated on cocaine and heroin drug trafficking, which occurs predominantly in Western countries.^{3,4,6,7,11,14,19} There is little research on the accuracy of plain abdominal radiography in MA drug carriers, although there has been a significant increase of MA in Asia, accompanied by draconian legal measures in cases of drug trafficking.^1,2 The purpose of this study was to retrospectively evaluate the sensitivity, specificity and accuracy of plain abdominal digital radiography (DRL) for identifying the internal payloads of MA in “drug mules”.     

Diffusion-weighted MRI in the follow-up of chronic periaortitis

Objective:

To evaluate the usefulness of diffusion-weighted MRI (DWI) for the assessment of the intraindividual follow-up in patients with chronic periaortitis (CP) under medication.

Methods:

MRI data of 21 consecutive patients with newly diagnosed untreated disease were retrospectively examined before and after medical therapy, with a median follow-up of 16 weeks. DWI parameters [b800 signal, apparent diffusion coefficient (ADC) values] of the CP and psoas muscle were analysed together with the extent and contrast enhancement. Pre- and post-treatment laboratory inflammation markers were acquired parallel to each MR examination.

Results:

Statistically significant lower b800 signal intensities (p ≤ 0.0001) and higher ADC values (p ≤ 0.0001) were observed after medical treatment within the fibrous periaortic tissue. Extent and contrast enhancement of the CP showed also a statistically significant decrease (p ≤ 0.0001) in the follow-up examinations, while the control parameters within the psoas muscle showed no differences.

Conclusion:

DWI seems to be a useful method for the evaluation of response to treatment without contrast agents. The technique may be helpful in the assessment of disease activity to guide further therapeutic strategies.

Advances in knowledge:

DWI detects significant differences in the intraindividual follow-up of CP under medical therapy.Chronic periaortitis (CP) is a proliferating fibroinflammatory disease of the perivascular retroperitoneal space and aortic wall.^1–4 Owing to adventitial inflammation, some recent theories consider CP as a large vessel vasculitis.⁵ Clinical manifestations of CP include idiopathic retroperitoneal fibrosis, inflammatory aortic aneurysm and perianeurysmal retroperitoneal fibrosis.^2,6,7 The three manifestations with very similar histopathological characteristics are distinguished by the diameter of the abdominal aorta and concomitant ureteral affection.^1,3,7Specific clinical symptoms are caused by extrinsic compression of the ureters or retroperitoneal veins, resulting in hydronephrosis, oliguria, lower extremity oedema and deep vein thrombosis.^1,8Under medical treatment with steroids, CP has a good prognosis.⁷ Today tamoxifen is suggested as a safe and effective therapeutic alternative, and immunosuppressive drugs can be considered in patients with suboptimal responses to these drugs or multiple relapses.^9–11CT and MRI are the modalities of first choice for diagnosis and follow-up of CP.^1,7,12 The fibrotic para-aortic tissue shows significant contrast uptake in gadolinium-enhanced MRI.^12–14 Dynamic contrast-enhanced MRI was suggested for the assessment of the disease activity.^15,16 However, in cases with impaired renal function (e.g. by ureteral compression), gadolinium-independent imaging methods should be preferred owing to the potential development of a nephrogenic systemic fibrosis.¹⁷Diffusion-weighted MRI (DWI) is a non-contrast MR modality that has been successfully applied for the assessment of retroperitoneal masses, inflammatory abdominal aortic aneurysms and for the differentiation between retroperitoneal fibrosis and malignant retroperitoneal neoplasms.^18–21DWI indicates restricted diffusion of water, for example caused by a high cellularity in malignant disease or active inflammation. The apparent diffusion coefficient (ADC) is a quantitative parameter for the level of restricted diffusion, which is calculated from the signals of different diffusion gradients (b-values).²²In the context of untreated CP diffusion-weighted MRI may detect restricted inflammation as a sign of high cellularity caused by active inflammation.There are no data for the evaluation of intraindividual follow-up and the response to treatment by DWI of CP so far. Therefore, the aim of the present study was to analyse differences in DWI signals during follow-up in patients with CP before and after treatment. In addition, we sought to elucidate the potential of DWI in the therapy monitoring of CP.     

125I particle implantation combined with chemoradiotherapy to treat advanced pancreatic cancer

Objective:

To evaluate the therapy effects of ¹²⁵I implantation combined with chemoradiotherapy on pancreatic cancer patients.

Methods:

30 patients with Stage III or IV pancreatic cancer were equally divided into two groups (control and treatment group). The patients in the treatment group (nine males, six females) received chemotherapy in the first week and ¹²⁵I implantation in the third week, followed by combined chemoradiotherapy in the fifth week. The patients in the control group (10 males, 5 females) received the same treatment except ¹²⁵I implantation. The therapy in the control group and treatment group was repeated every 4 weeks.

Results:

The median conformal radiotherapy dose in the treatment group (30.62 Gy) was significantly lower than that in the control group (47.86 Gy). The total radiation dose was 88.71 ± 27.39 Gy, and the surface activity was 0.6 mCi in the treatment group. After treatment, the average tumour size decreased both in the treatment group [9.17 cm², 95% confidence interval (CI): 5.60–12.74, p < 0.001] and in the control group (4.54 cm², 95% CI: 2.74–6.35, p < 0.001). The median survival time in the treatment group was 14 months (95% CI: 12.215–14.785) and in the control group was 12 months (95% CI: 10.884–13.116). There was no statistical significance in survival rates between the two groups (χ² = 0.908, p = 0.341).

Conclusion:

¹²⁵I implanted into tumour combined with chemoradiotherapy has higher local control rate of advanced pancreatic cancer than chemoradiotherapy.

Advances in knowledge:

We combined chemoradiotherapy with ¹²⁵I implantation to treat advanced pancreatic cancer and obtained a higher local control rate and better quality of life than when using chemoradiatherapy alone.Pancreatic cancer is currently one of the most intractable cancers with high and continually rising mortality in China.¹ The main risk factors are smoking, age and some genetic disorders, although the primary causes are poorly understood.² Pancreatic cancer causes no early symptoms, so the majority of patients are diagnosed as having advanced cancer with rapid progression when they come to the hospital.³ Thus, patients miss the opportunity for tumour resection when first diagnosed. Even if the cancer is discovered early, only 20% of patients can undergo surgical excision, whereas the other 80% cannot.² For patients who have undergone radical excision, the 5-year survival rate is just 20–25%.^4–9Advanced pancreatic cancer, according to the TNM stage of pancreatic carcinoma by the American Joint Committee on Cancer (AJCC),¹⁰ includes Stages III and IV, and pancreatectomy is not well accepted.¹¹ It is reported that approximately 40% of pancreatic cancer patients present with locally advanced, non-metastatic disease.¹² Local lesions play a vital role in a patient''s survival.^13–16 The aim of advanced pancreatic cancer treatment is to enhance local lesion control and improve the quality of life (QOL).^17,18Gemcitabine is a type of pyrimidine analogue, which acts as a ribonucleoside reductase inhibitor and destroys cells and terminates the DNA chains. It has been approved by the US Food and Drug Administration as a gold standard agent in chemotherapy¹⁹ for the treatment of cancer, especially for advanced pancreatic cancer.²⁰ Currently, the major therapy is comprehensive treatment, namely chemoradiotherapy, which is superior to either radiotherapy²¹ or chemotherapy.²² But the overall survival time is not prolonged by chemoradiotherapy in advanced pancreatic cancer compared with single-agent gemcitabine.²³ The 5-year survival rate is still <5%.²⁴ However, interstitial implantation of radioactive seeds (brachytherapy) combined with conformal radiotherapy (external beam radiation therapy) has a good effect for local control of pancreatic cancer.^{25,26 125}I particles are reported to be the most commonly used for brachytherapy because of their long half-life and short radiation distance.²⁷ Therefore, we infer that ¹²⁵I implantation combined with chemoradiation may obtain better curative effects.In this study, we compared the local control rate, pain relief and survival rate of 30 patients with advanced pancreatic cancer who were treated with or without ¹²⁵I implantation combined with chemoradiotherapy in our hospital during October 2006 to January 2012. We expected that the implantation of ¹²⁵I particles could be an efficient therapy for patients with advanced pancreatic cancer.     

The utility of MRI for pre-operative T and N staging of gastric carcinoma: a systematic review and meta-analysis

Objective:

To perform a meta-analysis and literature review regarding the diagnostic accuracy of MRI for pre-operative tumour depth invasion (T) and regional lymph node invasion (N) staging of gastric carcinoma (GC).

Methods:

Articles were identified through systematic search of Medline, PubMed, Cochrane Library, Web of Science, Springerlink and several Chinese databases. The study quality was assessed by the quality assessment for studies of diagnostic accuracy. 2 reviewers independently extracted and assessed the data from 11 eligible studies. A meta-analysis was then carried out. Subgroup and sensitivity analyses were also performed.

Results:

11 studies (439 patients) were finally included in the current review. Among these studies, the significant evidence of heterogeneity was only discovered for specificity in T4 stage (I² = 59.8%). Pooled sensitivity and specificity of MRI to diagnose T stage tumour (T3–4 vs T1–2) were 0.93 [95% confidence interval (CI), 0.89–0.96] and 0.91 (95% CI, 0.87–0.95), respectively. Pooled estimates of sensitivity and specificity of MRI to diagnose N stage tumour (N0 vs N+) were 0.86 (95% CI, 0.80–0.92) and 0.67 (95% CI, 0.54–0.79), respectively. Subgroup analyses showed that diffusion-weighted imaging was more helpful for T staging.

Conclusion:

The present systematic review suggests that MRI has a good diagnostic accuracy for pre-operative T staging of GC and should be widely used in clinical work. However, the ability for N staging is relatively poor on MRI.

Advances in knowledge:

In the pre-operative staging of GC, MRI was a useful tool and may enhance accuracy for the T staging of advanced GC.Gastric carcinoma (GC) is the fourth most common cancer and the second leading cause of cancer-related death with a 5-year survival rate of <20% around the world.¹ The disease is more common in Asian countries, especially China, Japan and Republic of Korea.^2,3 Accurate assessment of local tumour depth invasion (T) and regional lymph node invasion (N) plays an essential role in predicting prognosis and determining the most appropriate treatment planning.^4,5The pre-operative staging of GC has been based on a multimodality approach, such as endoscopic ultrasonography (EUS), CT, MRI and positron emission tomography (PET).^6,7 EUS and CT have been widely used for GC staging in previous years.⁸ Of course, different imaging modalities have themselves relative merits. CT with ionized radiation requires the injection of iodine contrast medium.⁹ EUS is an invasive technique requiring sedation¹ and is highly operator dependent.¹⁰ PET highly depends upon the standardized uptake value and the pathological subtype of the cancer.¹¹MRI is a powerful imaging method with high soft-tissue contrast, with technical versatility for sequence selection and modification, and without ionizing radiation. However, it was unsuitable for the staging of GC owing to its long acquisition time and susceptibility to motion artefacts in previous years. With technology improved and shorter imaging time, these limitations have recently been partially overcome.¹²Recently, there has been much research using MRI to assess pre-operative staging of GC. Nevertheless, the number of patients in each study has been insufficient, and the results varied among the articles. Also, the limited imaging field of view of MRI in a single session makes it difficult to stage the distant metastasis (M).¹³ Therefore, the objective of this study was to perform a systematic review and meta-analysis regarding the diagnostic accuracy of MRI for pre-operative T and N staging of GC.     

Medial temporal lobe atrophy in Alzheimer's disease/mild cognitive impairment with depression

Objective:

Depression is common in patients with Alzheimer''s disease (AD) and mild cognitive impairment (MCI). Patients with depression have an earlier onset and rapid progression of cognitive decline. Medial temporal lobe atrophy (MTA) is common in AD and MCI, and some degree of atrophy is found in almost all patients. In the present study, an attempt was made to know if MTA is more common in patients with AD/MCI with depression than those without it.

Methods:

Patients reporting to the outpatient department of a neurology centre of a tertiary care hospital were recruited for the present study. After initial general physical and neurological examination, they were evaluated using National Institute of Neurological and Communicative Disorders and Stroke and Related Disorders Association criteria for diagnosis of AD. Clinical Dementia rating scale was used for the diagnosis of MCI. Cornell scale for depression in dementia (CSDD) was used.

Results:

We found 20 cases with depression as per CSDD out of a sample of 37 patients (male:female = 30:7). There were 26 patients with AD and 11 with MCI. The mean age of all patients was 72.33 ± 6.45 years. The mean mini mental status examination score was 19.00 ± 6.73. The mean time since diagnosis was 4.19 ± 3.26 years. The mean Scheltens visual rating scale score for right MTA was 2.08 ± 0.95 and was 2.05 ± 0.94 for the left. Both scores did not differ statistically when analyzed using paired t-test (p > 0.05). However, difference in those with depression (2.36 ± 0.95) from those without depression (1.60 ± 0.74) was significant (p < 0.05).

Conclusion:

MTA scores were higher in those with AD/MCI with depression than those without it.Depression¹ is common in patients with Alzheimer''s disease (AD) and mild cognitive impairment (MCI). Relationship between depression and cognitive decline is a complex one, and depression is both an aetiological risk factor² and comorbidity for dementia.³ Incidence and prevalence of depressive symptoms in MCI range from 15% in population-based studies to 44% in hospital-based studies.⁴ Likewise, up to two-thirds of patients with AD have been reported to have depression.⁵ Because in many studies, depression has been seen to be an early manifestation of AD, it has been suggested that it may represent a continuum⁴ from depression to MCI to AD (late-life depression → MCI → AD). Two recent meta-analyses have found that a history of depression approximately doubles an individual''s risk for subsequent dementia in general and AD in particular.⁶ Depression is known to be neurotoxic to medial temporal lobe structures and can contribute to their atrophy.^7–9 Atrophy is more so, when depression is severe or recurrent⁷ and medial temporal lobe atrophy (MTA) has a temporal association with depression.⁹ Continued treatment of depression has been shown to protect the hippocampus from the ill effects of depression.¹⁰ Although volumetric method could be a preferred mode of measuring the hippocampal volume in AD, qualitative rating of MTA is a good alternative.¹¹ Visual rating of the hippocampal volume^12–14 can be carried out using Scheltens et al¹⁵ rating scale that is based on the width of the choroid fissure, the width of the temporal horn and the height of hippocampal formation and is a quantitative scale.     

Lung ischaemia–reperfusion injury in a canine model: dual-energy CT findings with pathophysiological correlation

Objective:

To evaluate dual-energy CT (DECT) findings of pulmonary ischaemic–reperfusion injury (PIRI) and its pathophysiological correlation in the canine model.

Methods:

A PIRI model was established in 11 canines, utilizing closed pectoral balloon occlusion. Two control canines were also included. For the PIRI model, the left pulmonary artery was occluded with a balloon, which was deflated and removed after 2 h. DECT was performed before, during occlusion and at 2, 3 and 4 h thereafter and was utilized to construct pulmonary perfusion maps. Immediately after the CT scan at the fourth hour post reperfusion, the canines were sacrificed, and lung specimens were harvested for pathological analysis. CT findings, pulmonary artery pressure and blood gas results were then analysed.

Results:

Data at every time point were available for 10 animals (experimental group, n = 8; control group, n = 2). Quantitative measurements from DECT pulmonary perfusion maps found iodine attenuation values of the left lung to be the lowest at 2 h post embolization and the highest at 1 h post reperfusion. In the contralateral lung, perfusion values also peaked at 1 h post reperfusion. Continuous hypoxia and acid–based disorders were observed during PIRI, and comprehensive analysis showed physiological changes to be worst at 3 h post reperfusion.

Conclusion:

DECT pulmonary perfusion mapping demonstrated pulmonary perfusion of the bilateral lungs to be the greatest at 1 h post reperfusion. These CT findings corresponded with pathophysiological changes.

Advances in knowledge:

DECT pulmonary perfusion mapping can be used to evaluate lung ischaemia–reperfusion injury.Ischaemia–reperfusion injury (IRI) occurs under a variety of clinical conditions, including lung and/or cardiac transplantation, cardiopulmonary bypass, pulmonary resection, re-expansion pulmonary oedema, shock, cardiopulmonary resuscitation and pulmonary embolism.^1–3 Pulmonary embolism is a common cause of pulmonary IRI (PIRI), and the incidence of pulmonary embolism is increasing^4,5 with a mortality rate of up to 30%.⁶ With timely identification and treatment of pulmonary embolism, mortality rates can be reduced to <10%.⁷ However, reperfusion after treatment for lung ischaemia can also cause serious complications, such as haemorrhage and pulmonary oedema.⁸ Therefore, it is important to understand both the pathophysiological and imaging appearances of pulmonary IRI. Lung transplantation is also a common cause for PIRI following pulmonary arterial occlusion. Currently, the incidence of PIRI following transplantation is estimated at up to 25%. Post transplantation, PIRI can lead to insufficiency of the primary lung graft, delayed graft function, acute or chronic rejection (e.g. pulmonary oedema and acute respiratory failure), and increased early post-operative mortality and graft failure.^9,10CT is currently the predominant modality for the imaging assessment of thoracic disorders, including PIRI. Dual-energy CT (DECT) allows simultaneous acquisition of dual-energy data sets, allowing for decomposition of the scanned entity based on differences in attenuation between air, soft tissue and iodine.¹¹ One application of this principle in pulmonary imaging is the ability to obtain iodine maps demonstrating the distribution of pulmonary perfusion. The use of CT perfusion mapping has been shown to be relatively sensitive and highly specific for the detection of pulmonary emboli.¹²Recent research into PIRI has focused on the pathological and molecular biological mechanisms.^13–16 To date, there are few reports on imaging and pathophysiological findings in PIRI.^17,18 CT perfusion findings in PIRI have also not yet been described. The aim of this study was to assess PIRI imaging and pathophysiological findings in a canine model.     

Differentiating benign and malignant salivary gland tumours: diagnostic criteria and the accuracy of dynamic contrast-enhanced MRI with high temporal resolution

Objective:

To determine the optimal diagnostic criterion of dynamic contrast-enhanced MRI (DCE-MRI) for predicting salivary gland malignancy using a dynamic sequence with high temporal resolution, as well as the accuracy of this technique.

Methods:

The DCE-MRI findings of 98 salivary gland tumours (74 benign and 24 malignant) were reviewed. MR images were sequentially obtained at 5-s intervals for 370 s. Two parameters, peak time and washout ratio (WR) were determined from the time–signal intensity curve. The optimal thresholds of these parameters for differentiating benign and malignant tumours were determined, along with the diagnostic accuracy of the criterion using these thresholds.

Results:

A peak time of 150 s and a WR of 30% were identified as optimal thresholds. As the criterion for malignancy, the combination of peak time <150 s and WR <30% provided a sensitivity of 79% (19/24), specificity of 95% (70/74) and an overall accuracy of 91% (89/98). Three of the five false-negative cases were malignant lymphomas of the parotid gland.

Conclusion:

Peak time <150 s with WR <30% comprised the optimal diagnostic criterion in predicting salivary gland malignancy, providing a sensitivity of 79% and specificity of 95%. The use of high temporal resolution might improve the accuracy of DCE-MRI.

Advances in knowledge:

Although several studies have reported the usefulness of DCE-MRI in the differential diagnosis of salivary gland tumours, the specific diagnostic criteria employed have differed widely. We determined the optimal criterion and its accuracy using a dynamic sequence with high temporal resolution.Salivary gland tumours account for approximately 3% of all tumours.¹ They can arise from any salivary gland, although the majority occur in the parotid gland.² Pre-operative differential diagnosis between benign and malignant salivary gland tumours is very important because the results strongly affect surgical treatment planning. Among various imaging techniques, MRI is now the modality of choice for evaluation of suspected salivary gland tumours.^3,4 Owing to its superb contrast resolution and multiplanar facilities, MRI can clearly identify a tumour''s exact location and extent, as well as its relationship with neighbouring structures. On the other hand, the sensitivity of conventional MRI in predicting malignancy is known to be quite low.^5–7Several researchers reported that time–signal intensity curves (TICs) obtained by dynamic contrast-enhanced MRI (DCE-MRI) were useful in the differential diagnosis of salivary gland tumours and that the TIC characterized by early enhancement and low washout was associated with malignancy.^4,8–15However, the specific criteria involved, that is, the definition of and thresholds for the time to peak enhancement and the washout ratio (WR), have varied widely among studies. Thus, the efficacy of DCE-MRI in the differential diagnosis of salivary gland tumours has not yet been fully established. To obtain accurate TICs, a dynamic MRI sequence with high temporal resolution should be used.^6,16 However, the temporal resolution in most of the previous studies was relatively low (15–60 s),^{8–12,14,17–20} which may partly explain the inconsistencies between reports.In this study, we applied DCE-MRI with a temporal resolution of 5 s to 98 cases with salivary gland tumours. Our aims were to evaluate the TICs of these cases and to determine the optimal diagnostic criteria for DCE-MRI as well as its accuracy in differentiating benign from malignant salivary gland tumours.     

Repeatability of quantitative metrics derived from MR diffusion tractography in paediatric patients with epilepsy

Objective:

To quantify the test–retest repeatability of mean diffusivity (MD) and fractional anisotropy (FA) derived from diffusion tensor imaging (DTI) tractography in a cohort of paediatric patients with localization-related epilepsy.

Methods:

30 patients underwent 2 DTI acquisitions [repetition time/echo time (ms), 7000/90; flip, 90°; b-value, 1000 s mm⁻²; voxel (mm), 2 × 2 × 2]. Two observers used Diffusion Toolkit and TrackVis (www.trackvis.org) to segment and analyse the following tracts: corpus callosum, corticospinal tracts, arcuate fasciculi, inferior longitudinal fasciculi and inferior fronto-occipital fasciculi. Mean MD and mean FA were calculated for each tract. Each observer independently analysed one of the DTI data sets for every patient.

Results:

Segmentation identified all tracts in all subjects, except the arcuate fasciculus. There was a highly consistent relationship between repeated observations of MD (r = 0.993; p < 0.0001) and FA (r = 0.990; p < 0.0001). For each tract, coefficients of variation ranged from 0.9% to 2.1% for MD and from 1.5% to 2.8% for FA. The 95% confidence limits (CLs) for change ranged from 2.8% to 6% for MD and from 4.3% to 8.6% for FA. For the arcuate fasciculus, Cohen''s κ for agreement between the observers (identifiable vs not identifiable) was 1.0.

Conclusion:

We quantified the repeatability of two commonly utilized scalar metrics derived from DTI tractography. For an individual patient, changes greater than the repeatability coefficient or 95% CLs for change are unlikely to be related to variability in their measurement.

Advances in knowledge:

Reproducibility of these metrics will aid in the design of future studies and might one day be used to guide management in patients with epilepsy.Epilepsy is a common neurological condition defined by recurrent unprovoked seizures that affects 1% of the population, including 1 in 200 children.^1,2 Unlike in adults, developmental lesions predominate as the source of seizures in children; in particular, focal cortical dysplasia is the most common anatomical substrate for intractable epilepsy in the paediatric population.³ A high proportion of epilepsies occurring in the setting of cortical malformations are pharmacoresistant,⁴ highlighting the importance of alternative management strategies. In appropriately selected patients who fail medical management, surgical resection of the dysplastic cortex can be curative. In such cases, pre-operative identification and complete resection of the structural lesion are important prognostic factors.^5,6 Decision making surrounding the pursuit of invasive alternatives is rarely straightforward, however, and in practice relies heavily on supplementary information provided by novel diagnostic techniques.Although surgical management is an attractive option for many patients with focal seizures, medical therapy continues to be adopted as the “safe” strategy in a significant portion of this population. However, there is good evidence to suggest that ongoing seizures and treatment with antiseizure medication might be associated with progressive alterations in white matter integrity.^7–9 Furthermore, these same ongoing processes can contribute to progressive functional decline.^10,11 As such, the ability to confidently identify progression of network alterations in an individual patient with epilepsy, whether on the basis of ongoing seizure activity, antiseizure medication or both, would be of great value to informed decision making surrounding potential surgical intervention.With the advent of diffusion-weighted imaging (DWI), the microstructural properties of a tissue of interest can be non-invasively probed at a spatial scale that is otherwise unattainable using even the most advanced structural MR techniques. Diffusion tensor imaging (DTI) is a variation on the theme of DWI, which quantifies water motion in three orthogonal dimensions and, therefore, is better able to capture the anisotropic tendencies of diffusion in highly organized tissues, such as cerebral white matter.¹² Numerous scalar metrics can be derived from the tensor; the most commonly referenced are mean diffusivity (MD) and fractional anisotropy (FA). MD provides a measure of overall incoherent motion within a voxel without regard for direction and reflects tissue organization at the cellular level.¹³ Increased MD is a common manifestation of white matter pathology of diverse aetiology.^14–16 By contrast, FA provides a measure of the degree to which a single direction of water motion dominates overall diffusivity in a voxel. As such, FA has been shown to be a relatively robust measure of white matter integrity.^17–21 Diffusion tractography is an extension of DTI in which the directional tendencies of water diffusion are used to create three-dimensional representations of white matter tracts based on their structural coherence.^22,23 In many instances, the functional role of the constructed pathways is at least in part known, which enables assessment of brain parenchymal abnormalities in terms of functional systems.^16,24DTI and diffusion tractography already occupy a prominent place in epilepsy research, and they are increasingly used to guide clinical management of epilepsy patients.^7,25–30 Although preliminary results are promising, a thorough understanding of the test–retest reproducibility of metrics derived from DTI will be crucial to the widespread application of this technique. Such knowledge would inform the design of both cross-sectional and longitudinal studies, including appropriate sample size selection. Furthermore, the clinical utility of such quantitative techniques will be predicated on an understanding of their intrinsic variability at the level of the individual. In particular, an understanding of what represents true difference at the individual level will be required to ascribe significance to changes in these metrics that occur in an individual patient. To date, however, the reproducibility of quantitative metrics derived from tractography has not been widely studied and, in particular, there are very few data from either the paediatric or epilepsy populations.³¹ The goal of this study, therefore, was to measure the repeatability of MD and FA derived from DTI tractography in a cohort of paediatric patients with localization-related epilepsy.     

Assessment of coincidence and defect sizes in Bankart and Hill–Sachs lesions after anterior shoulder dislocation: a radiological study

Objective:

Bankart and Hill–Sachs lesions are often associated with anterior shoulder dislocation. The MRI technique is sensitive in diagnosing both injuries. The aim of this study was to investigate Bankart and Hill–Sachs lesions with MRI to determine the correlation in occurrence and defect sizes of these lesions.

Methods:

Between 2006 and 2013, 446 patients were diagnosed with an anterior shoulder dislocation and 105 of these patients were eligible for inclusion in the study. All patients were examined using MRI. Bankart lesions were classified as cartilaginous or bony lesions. Hill–Sachs lesions were graded I–III using a modified Calandra classification.

Results:

The co-occurrence of injuries was high [odds ratio (OR) = 11.47; 95% confidence interval (CI) = 3.60–36.52; p < 0.001]. Patients older than 29 years more often presented with a bilateral injury (OR = 16.29; 95% CI = 2.71–97.73; p = 0.002). A correlation between a Bankart lesion and the grade of a Hill–Sachs lesion was found (ρ = 0.34; 95% CI = 0.16–0.49; p < 0.001). Bankart lesions co-occurred more often with large Hill–Sachs lesions (OR = 1.24; 95% CI = 1.02–1.52; p = 0.033).

Conclusion:

If either lesion is diagnosed, the patient is 11 times more likely to have suffered the associated injury. The size of a Hill–Sachs lesion determines the co-occurrence of cartilaginous or bony Bankart lesions. Age plays a role in determining the type of Bankart lesion as well as the co-occurrence of Bankart and Hill–Sachs lesions.

Advances in knowledge:

This study is the first to demonstrate the use of high-quality MRI in a reasonably large sample of patients, a positive correlation of Bankart and Hill–Sachs lesions in anterior shoulder dislocations and an association between the defect sizes.A shoulder dislocation is a traumatic event with an incidence of around 24 per 100 000 in North America.^1,2 Anterior shoulder dislocation is the most common direction, and most patients are male.^1–4 The highest incidence (48 per 100 000) was found between the ages of 20 and 29 years.² Anterior dislocation causes a typical impression fracture on the posterior humeral head, known as a Hill–Sachs lesion.^5,6 The labrum or the glenoid itself may also be damaged; these injuries are known as Bankart lesions.⁷Although Hill–Sachs lesions can be found in 47–100% of all patients with first-time or recurrent shoulder dislocation, a distinction must be drawn between cartilaginous and bony Bankart lesions.^8–13 Cartilaginous lesions occur more often than bony ones.¹⁴ However, Bankart and Hill–Sachs lesions do not necessarily occur simultaneously. In 2006, Widjaja et al¹⁵ reported that, if one of the lesions was identified, the other was 2.67 times as likely to be present. Yet, this result failed to reach statistical significance because of the small sample size. Griffith et al¹⁰ evaluated CT scans and found a weak correlation between glenoidal bone loss and the size of the Hill–Sachs lesion (p = 0.030). However, the more frequently occurring cartilaginous Bankart lesion was not considered in this study.The aim of the present study was to evaluate the association between defect sizes in Hill–Sachs and bony as well as cartilaginous Bankart lesions after anterior shoulder dislocation using MRI. We hypothesized that there exists a higher correlation than previously thought between temporal occurrence and defect size of the lesions. The results of this study should help to improve diagnostic and therapeutic procedures.     

Early assessment of chronic kidney dysfunction using contrast-enhanced ultrasound: a pilot study

Objective:

We performed a prospective study to evaluate the value of contrast-enhanced (CE) ultrasound in quantitative evaluation of renal cortex perfusion in patients with chronic kidney dysfunction (CKD Stage I–II).

Methods:

The present study was approved by the institutional ethics committee. The study focused on 41 consecutive patients (males, 32; females, 9; mean age, 55.0 ± 5.0 years) with clinical suspicion of CKD (Stages I–II). For both kidneys, CE ultrasound was performed after intravenous bolus injection of 1.0 ml SonoVue® (Bracco Imaging S.p.A., Milan, Italy). Time–intensity curves (TICs) and quantitative indexes were created with Qlab software (Philips, Bothell, WA). 45 healthy volunteers were included as control group. All statistical analyses were performed with SPSS® v. 15.0 software package (SPSS, Chicago, IL). A difference was considered statistically significant with p < 0.05.

Results:

Patients with CKD (Stages I–II) had no obvious change in the shape of TICs. Among all quantitative indexes, the changes of area under the curve (AUC), derived peak intensity (DPI) and slope rate of elevation curve (A) were statistically significant (p < 0.05). DPI <12 dB, A >2 and AUC >1300 dB s had high utility in the evaluation of CKD, with 81%, 73% and 78% specificities and 76%, 73% and 77% sensitivities.

Conclusion:

CE ultrasound might be valuable in the early evaluation of CKD. AUC, A and DPI might be valuable quantitative indexes.

Advances in knowledge:

Quantitative CE ultrasound analysis can be used for the standardized and early evaluation of renal dysfunction.Throughout the world, chronic kidney dysfunction (CKD) is a growing health concern because of its increasing prevalence and incidence rate.¹ Since CKD primarily involves perfusion changes in the renal cortex, assessment of tissue perfusion is an important component for the evaluation of CKD.² Early and detailed visualizations of perfusion changes of the renal cortex yield information about organ viability and function, which would be crucial to make diagnosis and to initiate early drug therapy.³Different non-invasive imaging modalities, such as multidetector CT,⁴ positron emission tomography,⁵ MRI⁶ and single-photon emission CT with ^99mTc-diethylenetriamine pentaacetic acid⁷ are used in the quantifications of tissue perfusions. However, high costs, reduced availability, long examination periods, patients'' exposure to radiation or nuclear tracers limited clinical applications of these techniques.^4–7 Greyscale renal ultrasound combined with colour Doppler flow imaging (CDFI) had become the main non-invasive imaging methods for evaluating the renal anatomy and blood flow.⁸ However, CDFI parameters such as the resistance index (RI) and peak systolic velocity (PSV) provided only indirect macrovasculature parameters, which could not directly assess renal cortex perfusion and were of limited diagnostic use in the CKD.⁹ To date, there was no reliable, accurate and convenient method to determine renal blood perfusion in vivo, thereby leading to difficulty in early and accurate diagnosis of CKD.In recent years, low mechanical index (MI) real-time contrast-enhanced (CE) ultrasound has been proposed as an alternative imaging technique in this area.¹⁰ Because microbubbles are blood-pool agents, when injected intravenously, they remain entirely intravascular, mix uniformly with blood in the circulation and possess the same intravascular rheology as red blood cells.¹¹ The advantages of CE ultrasound include the absence of ionizing radiation or nephrotoxicity, and the widespread availability. When CE ultrasound is performed immediately after a non-conclusive ultrasound study, only a short time was needed to arrive at a final diagnosis.¹² CE ultrasound has been recently used as a new imaging technique for quantifying tissue perfusion changes in the liver,¹³ heart¹⁴ and kidney.¹⁵ The large blood supply of the kidney was a good base for contrast studies, as >90% of kidney blood flow supplied the renal cortex by the renal arterioles and capillaries.¹⁶ Since CE ultrasound microbubbles remain strictly inside the vessels, they can be viewed as blood-pool markers enabling functional imaging of the kidney.¹⁷ The increase in echo signal intensity after microbubble injection may be quantified by dedicated software packages to produce time–intensity curves (TICs). Enhancement-based representations had been used to assess unilateral kidney dysfunction such as in renal artery stenosis by a simple analysis of the tracer concentration curve.¹⁸ These features made low MI CE ultrasound a promising technique in evaluation of renal cortex perfusion.The purpose of this initial study was to evaluate the feasibility of CE ultrasound to assess renal cortex tissue perfusion in the early stages of CKD (Stages I–II) by means of TICs. The diagnostic efficacy gained by quantitative CE ultrasound was compared with that of renal arterial PSV and RI measured by CDFI.     

Quantitative pixelwise myocardial perfusion maps from first-pass perfusion MRI

Objective:

To calculate and evaluate absolute quantitative myocardial perfusion maps from rest first-pass perfusion MRI.

Methods:

10 patients after revascularization of myocardial infarction underwent cardiac rest first-pass perfusion MRI. Additionally, perfusion examinations were performed in 12 healthy volunteers. Quantitative myocardial perfusion maps were calculated by using a deconvolution technique, and results were compared were the findings of a sector-based quantification.

Results:

Maps were typically calculated within 3 min per slice. For the volunteers, myocardial blood flow values of the maps were 0.51 ± 0.16 ml g⁻¹ per minute, whereas sector-based evaluation delivered 0.52 ± 0.15 ml g⁻¹ per minute. A t-test revealed no statistical difference between the two sets of values. For the patients, all perfusion defects visually detected in the dynamic perfusion series could be correctly reproduced in the maps.

Conclusion:

Calculation of quantitative perfusion maps from myocardial perfusion MRI examinations is feasible. The absolute quantitative maps provide additional information on the transmurality of perfusion defects compared with the visual evaluation of the perfusion series and offer a convenient way to present perfusion MRI findings.

Advances in knowledge:

Voxelwise analysis of myocardial perfusion helps clinicians to assess the degree of tissue damage, and the resulting maps are a good tool to present findings to patients.MRI is widely used for the evaluation of myocardial perfusion. Advantages of perfusion MRI are a higher spatial resolution compared with positron emission tomography (PET)^1,2 and single photon emission CT³ and the lack of exposure to radiation. Great efforts have been made to use MRI for quantitative evaluation of myocardial perfusion in the past years.^4,5 In clinical routine, however, evaluation of MRI perfusion examinations is performed by the visual analysis of the acquired images depicting areas remaining hypo-intense during the passage of the contrast agent bolus. One main reason for not quantifying myocardial perfusion is the sometimes-excessive user interaction time required for manual segmentation of the acquired images in the quantification process.If myocardial perfusion is quantified, in most studies, the high spatial resolution of the acquired MR images is not maintained. Instead, a sector-based evaluation is performed.^6,7 First attempts have been made to calculate myocardial perfusion maps to evaluate regional myocardial perfusion.^3,8–10 However, until now, these studies were performed in animals^8–10 or perfusion was only evaluated semiquantitatively.³ Recently, our group has published an automatic post-processing tool for quantitative perfusion evaluation.¹¹ That study focused on the automation of post-processing but confined itself on sectors of the myocardium. The next and consequent step is to evolve this technique to work on a pixel-by-pixel basis. Therefore, it was the goal of this study to develop and test a method that calculates pixelwise quantitative perfusion maps from myocardial perfusion MRI examinations. These maps might help the clinician in making a diagnosis by decreasing the number of images to be examined, because a pixelwise quantitative perfusion map demonstrates the information of a whole series of images obtained in a first-pass perfusion examination clearly arranged.