Multiparametric quantitative magnetic resonance imaging of uterine fibroids for prediction of growth rate-a pilot study.

Background: Uterine fibroid (UF) growth rate and future morbidity cannot be predicted. This can lead to sub-optimal clinical management, with women being lost to follow-up and later presenting with severe disease that may require hospitalization, transfusions, and urgent surgical interventions. Multi-parametric quantitative magnetic resonance imaging (MRI) could provide a biomarker to predict growth rate facilitating better-informed disease management and better clinical outcomes. We assessed the ability of putative quantitative and qualitative MRI predictive factors to predict UF growth rate. Methods: Twenty women with UFs were recruited and completed baseline and follow-up MRI exams, 1-2.5 years apart. The subjects filled out symptom severity and health-related quality of life questionnaires at each visit. A standard clinical pelvic MRI non-contrast exam was performed at each visit, followed by a contrast-enhanced multi-parametric quantitative MRI (mp-qMRI) exam with T2, T2*, and apparent diffusion coefficient (ADC) mapping and dynamic contrast-enhanced MRI. Up to 3 largest fibroids were identified and outlined on the T2-weighted sequence. Fibroid morphology and enhancement patterns were qualitatively assessed on dynamic contrast-enhanced MRI. The UFs' volumes and average T2, T2*, and ADC values were calculated. Pearson correlation coefficients were calculated between UF growth rate and T2, T2*, ADC, and baseline volume. Multiple logistic regression and receiver operating characteristic (ROC) analysis were performed to predict fast-growing UFs using combinations of up to 2 significant predictors. A significance level of alpha =0.05 was used. Results: Forty-four fibroids in 20 women had growth rate measurement available, and 36 fibroids in 16 women had follow-up quantitative MRI available. The distribution of fibroid growth rate was skewed, with approximately 20% of the fibroids exhibiting fast growth (>10 cc/year). However, there were no significant changes in median baseline and follow-up values of symptom severity and health-related quality of life scores. There was no change in average T2, T2*, and ADC at follow-up exams and there was a moderate to strong correlation to the fibroid growth rate in baseline volume and average T2 and ADC in slow-growing fibroids (<10 cc/year). A multiple logistic regression to identify fast growing UFs (>10 cc/year) achieved an area under the curve (AUC) of 0.80 with specificity of 69% at 100% sensitivity. Conclusions: The mp-qMRI parameters T2, ADC, and UF volume obtained at the time of initial fibroid diagnosis may be able to predict UF growth rate. Mp-qMRI could be integrated into the management of UFs, for individualized care and improved clinical outcomes.

Congestive Hepatopathy: Pathophysiology, Workup, and Imaging Findings with Pathologic Correlation.

Liver congestion is increasingly encountered in clinical practice and presents diagnostic pitfalls of which radiologists must be aware. The complex altered hemodynamics associated with liver congestion leads to diffuse parenchymal changes and the development of benign and malignant nodules. Distinguishing commonly encountered benign hypervascular lesions, such as focal nodular hyperplasia (FNH)-like nodules, from hepatocellular carcinoma (HCC) can be challenging due to overlapping imaging features. FNH-like lesions enhance during the hepatic arterial phase and remain isoenhancing relative to the background liver parenchyma but infrequently appear to wash out at delayed phase imaging, similar to what might be seen with HCC. Heterogeneity, presence of an enhancing capsule, washout during the portal venous phase, intermediate signal intensity at T2-weighted imaging, restricted diffusion, and lack of uptake at hepatobiliary phase imaging point toward the diagnosis of HCC, although these features are not sensitive individually. It is important to emphasize that the Liver Imaging Reporting and Data System (LI-RADS) algorithm cannot be applied in congested livers since major LI-RADS features lack specificity in distinguishing HCC from benign hypervascular lesions in this population. Also, the morphologic changes and increased liver stiffness caused by congestion make the imaging diagnosis of cirrhosis difficult. The authors discuss the complex liver macro- and microhemodynamics underlying liver congestion; propose a more inclusive approach to and conceptualization of liver congestion; describe the pathophysiology of liver congestion, hepatocellular injury, and the development of benign and malignant nodules; review the imaging findings and mimics of liver congestion and hypervascular lesions; and present a diagnostic algorithm for approaching hypervascular liver lesions. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Implementation of a high-resolution, high-contrast magnetic resonance imaging protocol with extended delayed phases for peritoneal mesothelioma.

Background: Imaging of peritoneal malignancies using conventional cross-sectional imaging is challenging, but accurate assessment of peritoneal disease burden could guide better selection for definitive surgery. Here we demonstrate feasibility of high-resolution, high-contrast magnetic resonance imaging (MRI) of peritoneal mesothelioma and explore optimal timing for delayed post-contrast imaging. Methods: Prospective data from inpatients with malignant peritoneal mesothelioma (MPM), imaged with a novel MRI protocol, were analyzed. The new sequences augmenting the clinical protocol were (I) pre-contrast coronal high-resolution T2-weighted single-shot fast spin echo (COR hr T2w SSH FSE) of abdomen and pelvis; and (II) post-contrast coronal high-resolution three-dimensional (3D) T1-weighted modified Dixon (COR hr T1w mDIXON) of abdomen, acquired at five delay times, up to 20 min after administration of a double dose of contrast agent. Quantitative analysis of contrast enhancement was performed using linear regression applied to normalized signal in lesion regions of interest (ROIs). Qualitative analysis was performed by three blinded radiologists. Results: MRI exams from 14 participants (age: mean ± standard deviation, 60±12 years; 71% male) were analyzed. The rate of lesion contrast enhancement was strongly correlated with tumor grade (cumulative nuclear score) (r=-0.65, P<0.02), with 'early' delayed phase (12 min post-contrast) and 'late' delayed phase (19 min post-contrast) performing better for higher grade and lower grade tumors, respectively, in agreement with qualitative scoring of image contrast. Conclusions: High-resolution, high-contrast MRI with extended post-contrast imaging is a viable modality for imaging peritoneal mesothelioma. Multiple, extended (up to 20 min post-contrast) delayed phases are necessary for optimal imaging of peritoneal mesothelioma, depending on the grade of disease.

Improving reader accuracy and specificity with the addition of hybrid multidimensional-MRI to multiparametric-MRI in diagnosing clinically significant prostate cancers.

PURPOSE: Compare reader performance when adding the Hybrid Multidimensional-MRI (HM-MRI) map to multiparametric MRI (mpMRI+HM-MRI) versus mpMRI alone and inter-reader agreement in diagnosing clinically significant prostate cancers (CSPCa). METHODS: All 61 patients who underwent mpMRI (T2-, diffusion-weighted (DWI), and contrast-enhanced scans) and HM-MRI (with multiple TE/b-value combinations) before prostatectomy or MRI-fused-transrectal ultrasound-guided biopsy between August, 2012 and February, 2020, were retrospectively analyzed. Two experienced readers (R1, R2) and two less-experienced readers (less than 6-year MRI prostate experience) (R3, R4) interpreted mpMRI without/with HM-MRI in the same sitting. Readers recorded the PI-RADS 3-5 score, lesion location, and change in score after adding HM-MRI. Each radiologist's mpMRI+HM-MRI and mpMRI performance measures (AUC, sensitivity, specificity, PPV, NPV, and accuracy) based on pathology, and Fleiss' kappa inter-reader agreement was calculated and compared. RESULTS: Per-sextant R3 and R4 mpMRI+HM-MRI accuracy (82% 81% vs. 77%, 71%; p=.006, <.001) and specificity (89%, 88% vs. 84%, 75%; p=.009, <.001) were higher than with mpMRI. Per-patient R4 mpMRI+HM-MRI specificity improved (48% from 7%; p<.001). R1 and R2 mpMRI+HM-MRI specificity per-sextant (80%, 93% vs. 81%, 93%; p=.51,>.99) and per-patient (37%, 41% vs. 48%, 37%; p=.16, .57) remained similar to mpMRI. R1 and R2 per-patient AUC with mpMRI+HM-MRI (0.63, 0.64 vs. 0.67, 0.61; p=.33, .36) remained similar to mpMRI, but R3 and R4 mpMRI+HM-MRI AUC (0.73, 0.62) approached R1 and R2 AUC. Per-patient inter-reader agreement, mpMRI+HM-MRI Fleiss Kappa, was higher than mpMRI (0.36 [95% CI 0.26, 0.46] vs. 0.17 [95% CI 0.07, 0.27]); p=.009). CONCLUSION: Adding HM-MRI to mpMRI (mpMRI+HM-MRI) improved specificity and accuracy for less-experienced readers, improving overall inter-reader agreement.

MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study.

OBJECTIVES: A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them. METHODS: Twelve radiologists from 8 institutions assessed baseline and restaging MRI scans of 39 patients. The participating radiologists were asked to assess MRI features and to categorize the overall response as complete or incomplete. The reference standard was pathological complete response or a sustained clinical response for > 2 years. RESULTS: We measured the accuracy and described the interobserver variability of interpretation of rectal cancer response between radiologists at different medical centers. Overall accuracy was 64%, with a sensitivity of 65% for detecting complete response and specificity of 63% for detecting residual tumor. Interpretation of the overall response was more accurate than the interpretation of any individual feature. Variability of interpretation was dependent on the patient and imaging feature investigated. In general, variability and accuracy were inversely correlated. CONCLUSIONS: MRI-based evaluation of response at restaging is insufficiently accurate and has substantial variability of interpretation. Although some patients' response to neoadjuvant treatment on MRI may be easily recognizable, as seen by high accuracy and low variability, that is not the case for most patients. KEY POINTS: • The overall accuracy of MRI-based response assessment is low and radiologists differed in their interpretation of key imaging features. • Some patients' scans were interpreted with high accuracy and low variability, suggesting that these patients' pattern of response is easier to interpret. • The most accurate assessments were those of the overall response, which took into consideration both T2W and DWI sequences and the assessment of both the primary tumor and the lymph nodes.

Comparing Radiologist Performance in Diagnosing Clinically Significant Prostate Cancer with Multiparametric versus Hybrid Multidimensional MRI.

Background Variability of acquisition and interpretation of prostate multiparametric MRI (mpMRI) persists despite implementation of the Prostate Imaging Reporting and Data System (PI-RADS) version 2.1 due to the range of reader experience and subjectivity of lesion characterization. A quantitative method, hybrid multidimensional MRI (HM-MRI), may introduce objectivity. Purpose To compare performance, interobserver agreement, and interpretation time of radiologists using mpMRI versus HM-MRI to diagnose clinically significant prostate cancer. Materials and Methods In this retrospective analysis, men with prostatectomy or MRI-fused transrectal US biopsy-confirmed prostate cancer underwent mpMRI (triplanar T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging) and HM-MRI (with multiple echo times and b value combinations) from August 2012 to February 2020. Four readers with 1-20 years of experience interpreted mpMRI and HM-MRI examinations independently, with a 4-week washout period between interpretations. PI-RADS score, lesion location, and interpretation time were recorded. mpMRI and HM-MRI interpretation time, interobserver agreement (Cronbach alpha), and performance of area under the receiver operating characteristic curve (AUC) analysis were compared for each radiologist with use of bootstrap analysis. Results Sixty-one men (mean age, 61 years ± 8 [SD]) were evaluated. Per-patient AUC was higher for HM-MRI for reader 4 compared with mpMRI (AUCs for readers 1-4: 0.61, 0.71, 0.59, and 0.64 vs 0.66, 0.60, 0.50, and 0.46; P = .57, .20, .32, and .04, respectively). Per-patient specificity was higher for HM-MRI for readers 2-4 compared with mpMRI (specificity for readers 1-4: 48%, 78%, 48%, and 46% vs 37%, 26%, 0%, and 7%; P = .34, P < .001, P < .001, and P < .001, respectively). Diagnostic performance improved for the reader least experienced with HM-MRI, reader 4 (AUC, 0.64 vs 0.46; P = .04). HM-MRI interobserver agreement (Cronbach alpha = 0.88 [95% CI: 0.82, 0.92]) was higher than that of mpMRI (Cronbach alpha = 0.26 [95% CI: 0.10, 0.52]; α > .60 indicates reliability; P = .03). HM-MRI mean interpretation time (73 seconds ± 43 [SD]) was shorter than that of mpMRI (254 seconds ± 133; P = .03). Conclusion Radiologists had similar or improved diagnostic performance, higher interobserver agreement, and lower interpretation time for clinically significant prostate cancer with hybrid multidimensional MRI than multiparametric MRI. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Turkbey in this issue.

Standardization of MRI Screening and Reporting in Individuals With Elevated Risk of Pancreatic Ductal Adenocarcinoma: Consensus Statement of the PRECEDE Consortium.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a dismal survival rate. Screening the general population for early detection of PDAC is not recommended, but because early detection improves survival, high-risk individuals, defined as those meeting criteria based on a family history of PDAC and/or the presence of known pathogenic germline variant genes with PDAC risk, are recommended to undergo screening with MRI and/or endoscopic ultrasound at regular intervals. The Pancreatic Cancer Early Detection (PRECEDE) Consortium was formed in 2018 and is composed of gastroenterologists, geneticists, pancreatic surgeons, radiologists, statisticians, and researchers from 40 sites in North America, Europe, and Asia. The overarching goal of the PRECEDE Consortium is to facilitate earlier diagnosis of PDAC for high-risk individuals to increase survival of the disease. A standardized MRI protocol and reporting template are needed to enhance the quality of screening examinations, improve consistency of clinical management, and facilitate multiinstitutional research. We present a consensus statement to standardize MRI screening and reporting for individuals with elevated risk of pancreatic cancer.

Research Priorities in Percutaneous Image- and Endoscopy-Guided Interventions for Biliary and Gallbladder Diseases: Proceedings from the Society of Interventional Radiology Foundation Multidisciplinary Research Consensus Panel.

Recent technological advancements, including the introduction of disposable endoscopes, have enhanced the role of interventional radiology (IR) in the management of biliary and gallbladder diseases. There are unanswered questions in this growing field. The Society of Interventional Radiology Foundation convened a virtual research consensus panel consisting of a multidisciplinary group of experts to develop a prioritized research agenda regarding percutaneous image- and endoscopy-guided procedures for biliary and gallbladder diseases. The panelists discussed current data, opportunities for IR, and future efforts to maximize IR's ability and scope. A recurring theme throughout the discussions was to find ways to reduce the total duration of percutaneous drains and improve patients' quality of life. After the presentations and discussions, research priorities were ranked on the basis of their clinical relevance and impact. The research ideas ranked top 3 were as follows: (a) percutaneous multimodality management of benign anastomotic biliary strictures (laser vs endobiliary ablation vs cholangioplasty vs drain upsize protocol alone), (b) ablation of intraductal cholangiocarcinoma with and without stent placement, and (c) cholecystoscopy/choledochoscopy and lithotripsy in nonsurgical patients with calculous cholecystitis. Collaborative, retrospective, and prospective research studies are essential to answer these questions and improve the management protocols for patients with biliary and gallbladder diseases.

A Clinically Optimal Protocol for the Imaging of Enteric Tubes: On the Basis of Radiologist Interpreted Diagnostic Utility and Radiation Dose Reduction.

RATIONALE AND OBJECTIVES: The purpose of this study was to develop and evaluate a patient thickness-based protocol specifically for the confirmation of enteric tube placements in bedside abdominal radiographs. Protocol techniques were set to maintain image quality while minimizing patient dose. MATERIALS AND METHODS: A total of 226 pre-intervention radiographs were obtained to serve as a baseline cohort for comparison. After the implementation of a thickness-based protocol, a total of 229 radiographs were obtained as part of an intervention cohort. Radiographs were randomized and graded for diagnostic quality by seven expert radiologists based on a standardized conspicuity scale (grades: 0 non-diagnostic to 3+). Basic patient demographics, body mass index, ventilatory status, and enteric tube type were recorded and subgroup analyses were performed. Effective dose was estimated for both cohorts. RESULTS: The dedicated thickness-based protocol resulted in a significant reduction in effective dose of 80% (p-value < 0.01). There was no significant difference in diagnostic quality between the two cohorts with 209 (92.5%) diagnostic radiographs in the baseline and 221 (96.5%) diagnostic radiographs in the thickness-based protocol (p-value 0.06). CONCLUSION: A protocol optimized for the confirmation of enteric tube placements was developed. This protocol results in lower patient effective dose, without sacrificing diagnostic accuracy. The technique chart is provided for reference. The protocol development process outlined in this work could be readily generalized to other imaging clinical tasks.

The role of imaging in diagnosis and management of malignant peritoneal mesothelioma: a systematic review.

PURPOSE: Imaging of the peritoneum and related pathology is a challenge. Among peritoneal diseases, malignant peritoneal mesothelioma (MPeM) is an uncommon tumor with poor prognosis. To date, there are no specific guidelines or imaging protocols dedicated for the peritoneum and MPeM. The objective of this study was to analyze the literature describing imaging modalities used for MPeM to determine their relative clinical efficacy and review commonly reported imaging features of MPeM to promote standardized reporting. METHODS: We performed a systematic review of original research articles discussing imaging modalities in MPeM from 1999 to 2020. Effectiveness measures and common findings were compared across imaging modalities. RESULTS: Among 582 studies analyzed, the most-used imaging modality was CT (54.3%). In the differentiation of MPeM from peritoneal carcinomatosis, one study found CT had a diagnostic sensitivity of 53%, specificity of 100%, and accuracy of 68%. Two studies found fluorodeoxyglucose positron emission tomography (FDG-PET) had sensitivity of 86-92%, specificity of 83-89%, and accuracy of 87-89%. Another study found magnetic resonance imaging (MRI) was the best predictor of the peritoneal carcinomatosis index. Characteristics shown to best differentiate MPeM from other diseases included ascites, peritoneal thickening, mesenteric thickening, pleural plaques, maximum tumor dimension, and number of masses. CONCLUSION: Most published MPeM imaging studies utilized CT. PET/CT or MRI appear promising, and future studies should compare effectiveness of these modalities. MPeM imaging reports should highlight ascites, number of and maximum tumor dimension, peritoneal/mesenteric thickening, and associated pleural plaques, allowing for better aggregation of MPeM imaging data across studies.

HCC: role of pre- and post-treatment tumor biology in driving adverse outcomes and rare responses to therapy.

Liver cancer is the fastest-growing cause of cancer deaths in the United States and is a complex disease. The response of hepatocellular carcinoma (HCC) to treatment can be variable. Predicting response to determine the most effective therapy is an active area of research. Our understanding of underlying factors which drive response to therapy is continually increasing. As more therapies for the treatment of this disease evolve, it is crucial to identify and match the ideal therapy for a particular tumor and patient. The potential predicative imaging features of tumor behavior, while of research interest, have not been validated for clinical use and do not currently inform treatment planning. If further validated though, prognostic features may be used in the future to personalize treatment plans according to individual patients and tumors. Unexpected post-treatment responses such as potential tumor biology changes and abscopal effect which are important to be aware of. This review is intended for radiologists who routinely interpret post treatment HCC imaging and is designed to increase their cognizance about how HCC tumor biology drives response to therapy and explore rare responses to therapy.

Hepatocellular carcinoma: metastatic pathways and extra-hepatic findings.

Although a small portion of patients with hepatocellular carcinoma (HCC) have radiologically evident extrahepatic disease at the initial presentation, a larger number of them develop metastatic disease later during the course of treatment or after definitive treatment. Furthermore, early metastatic disease could be overlooked by imaging due to small size and non-specificity of findings. Extrahepatic spread of HCC occurs via different pathways and is directly fueled by tumor biology and its molecular characteristics. Early and accurate detection of extrahepatic disease in patients with HCC has significant impact on management and selection of treatment options. Additionally, precise staging of disease will allow for better prediction of survival and outcome. Different pathways of regional and systemic spread of HCC with their proposed mechanisms and relevant underlying molecular derangement will be discussed in this article. Potential roles in management of patients with HCC will be discussed and reviewed in this article.

High spectral and spatial resolution MRI of prostate cancer: a pilot study.

PURPOSE: High spectral and spatial resolution (HiSS) MRI is a spectroscopic imaging method focusing on water and fat resonances that has good diagnostic utility in breast imaging. The purpose of this work was to assess the feasibility and potential utility of HiSS MRI for the diagnosis of prostate cancer. METHODS: HiSS MRI was acquired at 3 T from six patients who underwent prostatectomy, yielding a train of 127 phase-coherent gradient echo (GRE) images. In the temporal domain, changes in voxel intensity were analyzed and linear (R) and quadratic (R1, R2) quantifiers of signal logarithm decay were calculated. In the spectral domain, three signal scaling-independent parameters were calculated: water resonance peak width (PW), relative peak asymmetry (PRA), and relative peak distortion from ideal Lorentzian shape (PRD). Seven cancer and five normal tissue regions of interest were identified in correlation with pathology and compared. RESULTS: HiSS-derived quantifiers, except R2, showed high reproducibility (coefficients of variation, 5%-14%). Spectral domain quantifiers performed better than temporal domain quantifiers, with receiver operator characteristic areas under the curve ranging from of 0.83 to 0.91. For temporal domain parameters, the range was 0.74 to 0.91. Low absolute values of the coefficients of correlation between monoexponential decay markers (R, PW) and resonance shape markers (PRA, PRD) were observed (range, 0.23-0.38). CONCLUSION: The feasibility and potential diagnostic utility of HiSS MRI in the prostate at 3 T without an endorectal coil was confirmed. Weak correlation between well-performing markers indicates that complementary information could be leveraged to further improve diagnostic accuracy.

New prostate MRI techniques and sequences.

Prostate MRI has seen increasing interest in recent years and has led to the development of new MRI techniques and sequences to improve prostate cancer (PCa) diagnosis which are reviewed in this article. Numerous studies have focused on improving image quality (segmented DWI) and faster acquisition (compressed sensing, k-t-SENSE, PROPELLER). An increasing number of studies have developed new quantitative and computer-aided diagnosis methods including artificial intelligence (PROSTATEx challenge) that mitigate the subjective nature of mpMRI interpretation. MR fingerprinting allows rapid, simultaneous generation of quantitative maps of multiple physical properties (T1, T2), where PCa are characterized by lower T1 and T2 values. New techniques like luminal water imaging (LWI), restriction spectrum imaging (RSI), VERDICT and hybrid multi-dimensional MRI (HM-MRI) have been developed for microstructure imaging, which provide information similar to histology. The distinct MR properties of tissue components and their change with the presence of cancer is used to diagnose prostate cancer. LWI is a T2-based imaging technique where long T2-component corresponding to luminal water is reduced in PCa. RSI and VERDICT are diffusion-based techniques where PCa is characterized by increased signal from intra-cellular restricted water and increased intracellular volume fraction, respectively, due to increased cellularity. VERDICT also reveal loss of extracellular-extravascular space in PCa due to loss of glandular structure. HM-MRI measures volumes of prostate tissue components, where PCa has reduced lumen and stromal and increased epithelium volume similar to results shown in histology. Similarly, molecular imaging using hyperpolarized 13C imaging has been utilized.

Reminiscing on Remnants: Imaging of Meckel Diverticulum and Its Complications in Adults.

OBJECTIVE: Meckel diverticulum may become symptomatic if it is complicated by hemorrhage, intestinal obstruction, diverticulitis, or tumor. Although classically described in children, it is often missed in adults because of lack of suspicion and difficulty in detection. The purpose of this article is to review the imaging findings and management of Meckel diverticulum and its complications. CONCLUSION: Although it is infrequently encountered incidentally, Meckel diverticulum should be considered especially when interpreting examinations for abdominal pain, small-bowel obstruction, and gastrointestinal bleeding.

Evaluation of the need for routine esophagram after peroral endoscopic myotomy (POEM).

BACKGROUND: Peroral endoscopic myotomy (POEM) is a novel surgical option for the treatment of achalasia. Most centers perform a routine esophagram on postoperative day (POD) #1 to rule esophageal perforation and leaks. In this study, we sought to determine the clinical utility of routine contrast studies post-POEM. METHODS: POEM was performed using an anterior submucosal tunnel and selective myotomy of the circular muscle layer. A routine contrast esophagram was obtained on POD #1. We conducted a retrospective review of the radiologists' interpretations of these studies and compared them to patient's clinical course. RESULTS: Seventy-eight patients were included. Among these, two complications occurred. One patient was non-compliant with postoperative nil per os orders and developed epigastric pain suspicious for a leak that was demonstrated on esophagram. Another patient had subcutaneous emphysema on POD #1 esophagram, a finding that was also present on physical examination, without esophageal leakage. Another esophagram in an asymptomatic patient was suspicious for submucosal tunnel hematoma which prompted a return to the operating room with negative results. Overall, 56 patients had abnormal studies. POD #1 esophagram demonstrated a sensitivity of 100 % and specificity of 45 % in identifying clinically significant complications. CONCLUSIONS: In this series, we found routine esophagram to have a high sensitivity but a very low specificity in detecting clinically significant complications. Routine esophagram after POEM may not be necessary.

Magnetic resonance imaging of pancreatic metastases from renal cell carcinoma.

Pancreatic metastases are rare but are thought to be most commonly from renal cell carcinoma (RCC). These metastases can present many years after the initial tumor is resected, and accordingly, these patients require prolonged imaging follow-up. Although the computed tomographic findings of these metastases have been extensively reviewed in the literature, little has been written about the magnetic resonance imaging appearance of these metastases. Pancreatic metastases from RCC are typically T1 hypointense and T2 hyperintense. After intravenous administration of gadolinium, they are typically hypervascular and less commonly hypovascular. Chemical shift and diffusion-weighted imaging can aid in the diagnosis of these metastases.

Reproducibility of mRECIST in assessing response to transarterial radioembolization therapy in hepatocellular carcinoma.

UNLABELLED: The purpose of our study was to evaluate the reproducibility of Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in hepatocellular carcinoma (HCC) lesions undergoing transarterial radioembolization (TARE) therapy and to determine whether mRECIST reproducibility is affected by the enhancement pattern of HCC. One hundred and three HCC lesions from 103 patients treated with TARE were evaluated. The single longest diameter of viable tumor tissue was measured by two radiologists at baseline; response to therapy was evaluated according to mRECIST. The enhancement pattern of HCC lesions was correlated with their mRECIST response. The response rate between mRECIST and RECIST 1.1 was compared. Wilcoxon signed-rank test, paired t test, Lin's concordance correlation coefficient (ρc ), Bland-Altman plot, kappa statistics, and Fisher's exact test were used to assess intra- and interobserver reproducibilities and to compare response rates. There were better intra- than interobserver agreements in the measurement of single longest diameter of viable tumor tissue (bias = 0 cm intraobserver versus bias = 0.3 cm interobserver). For mRECIST, good intraobserver (ĸ = 0.70) and moderate interobserver (ĸ = 0.56) agreements were noted. The mRECIST response for HCC lesions with homogeneous enhancement at both baseline and follow-up imaging showed better intra- and interobserver agreements (ĸ = 0.77 and 0.60, respectively) than lesions with heterogeneous enhancement at both scans (ĸ = 0.54 and 0.40, respectively). In the early follow-up period mRECIST showed a significantly higher response rate than RECIST (40.8% versus 3.9%; P = 0.025). CONCLUSIONS: In HCC patients treated with TARE, mRECIST captures a significantly higher response rate compared with RECIST; it also demonstrates acceptable intra- and interobserver reproducibilities for HCC lesions treated with TARE, and mRECIST reproducibility may be lower for HCC lesions with heterogeneous distribution of the viable tumor tissue.