Automated Artificial Intelligence Model Trained on a Large Data Set Can Detect Pancreas Cancer on Diagnostic Computed Tomography Scans As Well As Visually Occult Preinvasive Cancer on Prediagnostic Computed Tomography Scans.

BACKGROUND & AIMS: The aims of our case-control study were (1) to develop an automated 3-dimensional (3D) Convolutional Neural Network (CNN) for detection of pancreatic ductal adenocarcinoma (PDA) on diagnostic computed tomography scans (CTs), (2) evaluate its generalizability on multi-institutional public data sets, (3) its utility as a potential screening tool using a simulated cohort with high pretest probability, and (4) its ability to detect visually occult preinvasive cancer on prediagnostic CTs. METHODS: A 3D-CNN classification system was trained using algorithmically generated bounding boxes and pancreatic masks on a curated data set of 696 portal phase diagnostic CTs with PDA and 1080 control images with a nonneoplastic pancreas. The model was evaluated on (1) an intramural hold-out test subset (409 CTs with PDA, 829 controls); (2) a simulated cohort with a case-control distribution that matched the risk of PDA in glycemically defined new-onset diabetes, and Enriching New-Onset Diabetes for Pancreatic Cancer score ≥3; (3) multi-institutional public data sets (194 CTs with PDA, 80 controls), and (4) a cohort of 100 prediagnostic CTs (i.e., CTs incidentally acquired 3-36 months before clinical diagnosis of PDA) without a focal mass, and 134 controls. RESULTS: Of the CTs in the intramural test subset, 798 (64%) were from other hospitals. The model correctly classified 360 CTs (88%) with PDA and 783 control CTs (94%), with a mean accuracy 0.92 (95% CI, 0.91-0.94), area under the receiver operating characteristic (AUROC) curve of 0.97 (95% CI, 0.96-0.98), sensitivity of 0.88 (95% CI, 0.85-0.91), and specificity of 0.95 (95% CI, 0.93-0.96). Activation areas on heat maps overlapped with the tumor in 350 of 360 CTs (97%). Performance was high across tumor stages (sensitivity of 0.80, 0.87, 0.95, and 1.0 on T1 through T4 stages, respectively), comparable for hypodense vs isodense tumors (sensitivity: 0.90 vs 0.82), different age, sex, CT slice thicknesses, and vendors (all P > .05), and generalizable on both the simulated cohort (accuracy, 0.95 [95% 0.94-0.95]; AUROC curve, 0.97 [95% CI, 0.94-0.99]) and public data sets (accuracy, 0.86 [95% CI, 0.82-0.90]; AUROC curve, 0.90 [95% CI, 0.86-0.95]). Despite being exclusively trained on diagnostic CTs with larger tumors, the model could detect occult PDA on prediagnostic CTs (accuracy, 0.84 [95% CI, 0.79-0.88]; AUROC curve, 0.91 [95% CI, 0.86-0.94]; sensitivity, 0.75 [95% CI, 0.67-0.84]; and specificity, 0.90 [95% CI, 0.85-0.95]) at a median 475 days (range, 93-1082 days) before clinical diagnosis. CONCLUSIONS: This automated artificial intelligence model trained on a large and diverse data set shows high accuracy and generalizable performance for detection of PDA on diagnostic CTs as well as for visually occult PDA on prediagnostic CTs. Prospective validation with blood-based biomarkers is warranted to assess the potential for early detection of sporadic PDA in high-risk individuals.

Bounding box-based 3D AI model for user-guided volumetric segmentation of pancreatic ductal adenocarcinoma on standard-of-care CTs.

OBJECTIVES: To develop a bounding-box-based 3D convolutional neural network (CNN) for user-guided volumetric pancreas ductal adenocarcinoma (PDA) segmentation. METHODS: Reference segmentations were obtained on CTs (2006-2020) of treatment-naïve PDA. Images were algorithmically cropped using a tumor-centered bounding box for training a 3D nnUNet-based-CNN. Three radiologists independently segmented tumors on test subset, which were combined with reference segmentations using STAPLE to derive composite segmentations. Generalizability was evaluated on Cancer Imaging Archive (TCIA) (n = 41) and Medical Segmentation Decathlon (MSD) (n = 152) datasets. RESULTS: Total 1151 patients [667 males; age:65.3 ± 10.2 years; T1:34, T2:477, T3:237, T4:403; mean (range) tumor diameter:4.34 (1.1-12.6)-cm] were randomly divided between training/validation (n = 921) and test subsets (n = 230; 75% from other institutions). Model had a high DSC (mean ± SD) against reference segmentations (0.84 ± 0.06), which was comparable to its DSC against composite segmentations (0.84 ± 0.11, p = 0.52). Model-predicted versus reference tumor volumes were comparable (mean ± SD) (29.1 ± 42.2-cc versus 27.1 ± 32.9-cc, p = 0.69, CCC = 0.93). Inter-reader variability was high (mean DSC 0.69 ± 0.16), especially for smaller and isodense tumors. Conversely, model's high performance was comparable between tumor stages, volumes and densities (p > 0.05). Model was resilient to different tumor locations, status of pancreatic/biliary ducts, pancreatic atrophy, CT vendors and slice thicknesses, as well as to the epicenter and dimensions of the bounding-box (p > 0.05). Performance was generalizable on MSD (DSC:0.82 ± 0.06) and TCIA datasets (DSC:0.84 ± 0.08). CONCLUSION: A computationally efficient bounding box-based AI model developed on a large and diverse dataset shows high accuracy, generalizability, and robustness to clinically encountered variations for user-guided volumetric PDA segmentation including for small and isodense tumors. CLINICAL RELEVANCE: AI-driven bounding box-based user-guided PDA segmentation offers a discovery tool for image-based multi-omics models for applications such as risk-stratification, treatment response assessment, and prognostication, which are urgently needed to customize treatment strategies to the unique biological profile of each patient's tumor.

Secretin-Enhanced MRCP: How and Why-AJR Expert Panel Narrative Review.

Secretin-enhanced MRCP (S-MRCP) has advantages over standard MRCP for imaging of the pancreaticobiliary tree. Through the use of secretin to induce fluid production from the pancreas and leveraging of fluid-sensitive MRCP sequences, S-MRCP facilitates visualization of ductal anatomy, and the findings provide insight into pancreatic function, allowing radiologists to provide additional insight into a range of pancreatic conditions. This narrative review provides detailed information on the practical implementation of S-MRCP, including patient preparation, logistics of secretin administration, and dynamic secretin-enhanced MRCP acquisition. Also discussed are radiologists' interpretation and reporting of S-MRCP examinations, including assessments of dynamic compliance of the main pancreatic duct and of duodenal fluid volume. Established indications for S-MRCP include pancreas divisum, anomalous pancreaticobiliary junction, Santorinicele, Wirsungocele, chronic pancreatitis, main pancreatic duct stenosis, and assessment of complex postoperative anatomy. Equivocal or controversial indications are also described along with an approach to such indications. These indications include acute and recurrent acute pancreatitis, pancreatic exocrine function, sphincter of Oddi dysfunction, and pancreatic neoplasms.

Second Malignancies after Radiation Therapy: Update on Pathogenesis and Cross-sectional Imaging Findings.

A wide spectrum of second cancers occur as late complications of radiation therapy (RT) used to treat various malignancies. In addition to the type and dose of radiation, lifestyle, environmental, and genetic factors are important to the development of second malignancies in cancer survivors. Typically, RT-induced malignancies (RTIMs) are biologically aggressive cancers with a variable period of 5-10 years for hematologic malignancies and 10-60 years for solid tumors between RT and the development of the second cancer. Although carcinomas and leukemias commonly develop after low-dose RT, sarcomas occur in tissues or organs that receive high-dose RT. Angiosarcomas and unclassified pleomorphic sarcomas are the two most common RT-associated sarcomas; other sarcomas include malignant peripheral nerve sheath tumors, leiomyosarcomas, osteosarcomas, chondrosarcomas, and dedifferentiated or pleomorphic liposarcomas. Select RTIMs show tumor genetic characteristics that allow accurate diagnosis. Nearly all cutaneous angiosarcomas after RT for breast cancer and 90% of RT-associated malignant peripheral nerve sheath tumors are characterized by MYC gene amplifications and loss of H3 K27me3 expression, respectively. Classic papillary thyroid carcinomas that develop after RT frequently harbor RET/PTC rearrangements and have a favorable prognosis, despite their advanced stage at patient presentation. Select RTIMs demonstrate characteristic imaging findings and typically develop in the prior radiation field. Imaging is essential to early diagnosis, characterization, localization, and staging of RTIMs. Familiarity of radiologists with the diverse spectrum of RTIMs is essential for early diagnosis and optimal management. An invited commentary by Shapiro is available online. ©RSNA, 2021.

The Lesser Sac and Foramen of Winslow: Anatomy, Embryology, and CT Appearance of Pathologic Processes.

OBJECTIVE. This article reviews the embryologic development, relevant anatomy, and imaging features, on CT, of pathologic processes involving the lesser sac and foramen of Winslow. CONCLUSION. The lesser peritoneal sac is an intricate anatomic region involved in many disease processes. It is a significant conduit for the spread of disease within the peritoneal cavity. The spectrum of pathologic processes pertaining to the lesser sac can be classified on the basis of the type of involvement, such as a fluid collection (e.g., transudate, exudate, bile, and blood), a mass (e.g., neoplastic or nonneoplastic conditions and lymphadenopathy), or an internal hernia into the lesser sac.

Phase 1 study of EUS-guided photodynamic therapy for locally advanced pancreatic cancer.

BACKGROUND AND AIMS: Locally advanced pancreatic cancer (LAPC) has a poor prognosis. There are limited data describing the use of photodynamic therapy (PDT) for pancreatic cancer in humans. We hypothesized that EUS-guided PDT for LAPC is safe, technically feasible, and produces a dose- and time-dependent increasing degree of image-defined tumor necrosis. METHODS: In a single-center, prospective, dose-escalation phase 1 study, patients with treatment-naïve LAPC received intravenous porfimer sodium (Concordia Laboratories Inc, St Michael, Barbados) followed 2 days later by EUS-PDT. EUS-PDT was performed by puncture with a 19-gauge needle and insertion of a 1.0-cm light diffuser (Pioneer Optics, Bloomfield, Conn) and illumination with a 630-nm light (Diomed Inc, Andover, Mass). A CT scan 18 days after PDT was done to assess for change in pancreatic necrosis. Nab-paclitaxel (125 mg/ m2 intravenously) and gemcitabine (1000 mg /m2 intravenously) were initiated 7 days after CT and given weekly for 3 of 4 weeks (1 cycle) until disease progression or unacceptable toxicity. RESULTS: Twelve patients (mean age, 67 ± 6 years; 8 male) with tumors (mean diameter, 45.2 ± 12.9 mm) in the head and/or neck (8) or body and/or tail (4) underwent EUS-PDT. Compared with baseline imaging, increased volume and percentage of tumor necrosis were observed in 6 of 12 patients (50%) after EUS-PDT. The mean overall increases in volume and percentage necrosis were 10 ± 26 cm3 (P = .20) and 18% ± 22% (P = .016), respectively. After a median follow-up of 10.5 months (range, 1.0-37.4 months), median progression-free (PFS) and overall survival (OS) were 2.6 months (95% confidence interval, 0.7, not estimable) and 11.5 months (95% confidence interval, 1.1, 16.9), respectively. Surgical resection was attempted in 2 patients, and pathology showed a complete response (n = 1) and residual 2-mm tumor (n = 1). There were 8 serious adverse events and none related to EUS or EUS-PDT. CONCLUSION: EUS-PDT for LAPC appears to be safe and produces measurable imaged-defined tumor necrosis. Phase 2 studies are warranted. (Clinical trial registration number: NCT01770132.).

CT texture analysis of pancreatic cancer.

OBJECTIVES: We investigated the value of CT texture analysis (CTTA) in predicting prognosis of unresectable pancreatic cancer. METHODS: Sixty patients with unresectable pancreatic cancers at presentation were enrolled for post-processing with CTTA using commercially available software (TexRAD Ltd, Cambridge, UK). The largest cross-section of the tumour on axial CT was chosen to draw a region-of-interest. CTTA parameters (mean value of positive pixels (MPP), kurtosis, entropy, skewness), arterial and venous invasion, metastatic disease and tumour size were correlated with overall and progression-free survivals. RESULTS: The median overall and progression-free survivals of cohort were 13.3 and 7.8 months, respectively. On multivariate Cox proportional hazard regression analysis, presence of metastatic disease at presentation had the highest association with overall survival (p = 0.003-0.05) and progression-free survival (p < 0.001 to p = 0.004). MPP at medium spatial filter was significantly associated with poor overall survival (p = 0.04). On Kaplan-Meier survival analysis of CTTA parameters at medium spatial filter, MPP of more than 31.625 and kurtosis of more than 0.565 had significantly worse overall survival (p = 0.036 and 0.028, respectively). CONCLUSIONS: CTTA features were significantly associated with overall survival in pancreas cancer, particularly in patients with non-metastatic, locally advanced disease. KEY POINTS: • CT texture analysis is easy to perform on contrast-enhanced CT. • CT texture analysis can determine prognosis in patients with unresectable pancreas cancer. • The best predictors of poor prognosis were high kurtosis and MPP.

Agreement Between Magnetic Resonance Imaging Proton Density Fat Fraction Measurements and Pathologist-Assigned Steatosis Grades of Liver Biopsies From Adults With Nonalcoholic Steatohepatitis.

BACKGROUND & AIMS: We assessed the diagnostic performance of magnetic resonance imaging (MRI) proton density fat fraction (PDFF) in grading hepatic steatosis and change in hepatic steatosis in adults with nonalcoholic steatohepatitis (NASH) in a multi-center study, using central histology as reference. METHODS: We collected data from 113 adults with NASH participating in a multi-center, randomized, double-masked, placebo-controlled, phase 2b trial to compare the efficacy cross-sectionally and longitudinally of obeticholic acid vs placebo. Hepatic steatosis was assessed at baseline and after 72 weeks of obeticholic acid or placebo by liver biopsy and MRI (scanners from different manufacturers, at 1.5T or 3T). We compared steatosis estimates by PDFF vs histology. Histologic steatosis grade was scored in consensus by a pathology committee. Cross-validated receiver operating characteristic (ROC) analyses were performed. RESULTS: At baseline, 34% of subjects had steatosis grade 0 or 1, 39% had steatosis grade 2, and 27% had steatosis grade 3; corresponding mean PDFF values were 9.8%±3.7%, 18.1%±4.3%, and 30.1%±8.1%. PDFF classified steatosis grade 0-1 vs 2-3 with an area under the ROC curve (AUROC) of 0.95 (95% CI, 0.91-0.98), and grade 0-2 vs grade 3 steatosis with an AUROC of 0.96 (95% CI, 0.93-0.99). PDFF cut-off values at 90% specificity were 16.3% for grades 2-3 and 21.7% for grade 3, with corresponding sensitivities of 83% and 84%. After 72 weeks' of obeticholic vs placebo, 42% of subjects had a reduced steatosis grade (mean reduction in PDFF from baseline of 7.4%±8.7%), 49% had no change in steatosis grade (mean increase in PDFF from baseline of 0.3%±6.3%), and 9% had an increased steatosis grade (mean increase in PDFF from baseline of 7.7%±6.0%). PDFF change identified subjects with reduced steatosis grade with an AUROC of 0.81 (95% CI, 0.71-0.91) and increased steatosis grade with an AUROC of 0.81 (95% CI, 0.63-0.99). A PDFF reduction of 5.15% identified subjects with reduced steatosis grade with 90% specificity and 58% sensitivity, whereas a PDFF increase of 5.6% identified those with increased steatosis grade with 90% specificity and 57% sensitivity. CONCLUSIONS: Based on data from a phase 2 randomized controlled trial of adults with NASH, PDFF estimated by MRI scanners of different field strength and at different sites, accurately classifies grades and changes in hepatic steatosis when histologic analysis of biopsies is used as a reference.

Can functional parameters from hepatobiliary phase of gadoxetate MRI predict clinical outcomes in patients with cirrhosis?

OBJECTIVES: To determine the value of quantitative parameters of gadoxetate-enhanced magnetic resonance imaging (MRI) in predicting prognosis in patients with cirrhosis. METHODS: A cohort of 63 cirrhotic patients who had gadoxetate MRI and 2-year clinical follow-up was enrolled. Enhancement ratio (ER), contrast enhancement index (CEI) and contrast enhancement spleen index (CES) were calculated. The usefulness of these parameters and clinical scores, such as Child-Pugh score (CPS) and model for end stage liver disease (MELD), in predicting adverse outcomes, such as variceal bleeding (VB), hepatic encephalopathy (HE) and mortality at 2 years were evaluated. RESULTS: Fifteen, 31 and 27 patients, respectively, had VB, HE and mortality within 2 years. The ER at 15 min (ER 15) and CES at 20 min (CES 20) were found to be the best MRI predictors. Areas under the receiver operating characteristic curve (AUC) for predicting VB were 0.785, 0.729, 0.673, 0.714, respectively, for ER 15, CES 20, CPS and MELD scores. ER 15 of less than 48 had sensitivity of 96% and specificity of 84% for predicting onset of HE within 2 years. CONCLUSIONS: In patients with cirrhosis, ER 15 or CES 20 were equivalent or better predictors of major morbidity and mortality compared with commonly used clinical scores. KEY POINTS: • Gadoxetate parameters may identify cirrhotic patients at risk of adverse events. • Gadoxetate parameters usually show superior predictive values compared to clinical scores. • CES 20 score is associated with risk of mortality within 2 years.

A Multidisciplinary Approach to Pancreas Cancer in 2016: A Review.

In this article, we review our multidisciplinary approach for patients with pancreatic cancer. Specifically, we review the epidemiology, diagnosis and staging, biliary drainage techniques, selection of patients for surgery, chemotherapy, radiation therapy, and discuss other palliative interventions. The areas of active research investigation and where our knowledge is limited are emphasized.

The Value of Secretin-Enhanced MRCP in Patients With Recurrent Acute Pancreatitis.

OBJECTIVE: The purpose of this study is to assess the additional value of secretin-enhanced MRCP over conventional (non-secretin-enhanced) MRCP in diagnosing disease in patients with recurrent acute pancreatitis. MATERIALS AND METHODS: A retrospective review of a radiology database found 72 patients with recurrent acute pancreatitis who had secretin-enhanced MRCP and ERCP correlation within 3 months of each other between January 2007 and December 2011. Of these patients, 54 had no history of pancreatic tumor or surgery and underwent MRI more than 3 months after an episode of acute pancreatitis. In addition, 57 age- and sex-matched control subjects with secretin-enhanced MRCP and ERCP correlation and without a diagnosis of recurrent acute pancreatitis or chronic pancreatitis were enrolled as the control group. All studies were anonymized, and secretin-enhanced MRCP images (image set A) were separated from conventional 2D and 3D MRCP and T2-weighted images (image set B). Image sets A and B for each patient were assigned different and randomized case numbers. Two blinded reviewers independently assessed both image sets for ductal abnormalities and group A image sets for exocrine response to secretin. RESULTS: There were statistically significantly more patients with recurrent acute pancreatitis with reduced exocrine function compared with patients in the control group (32% vs 9%; p < 0.01) on secretin-enhanced images. Patients with recurrent acute pancreatitis were more likely to have side branch dilation (p = 0.02; odds ratio, 3.6), but not divisum, compared with the control group. Secretin-enhanced images were superior to non-secretin-enhanced images for detecting ductal abnormalities in patients with recurrent acute pancreatitis, with higher sensitivity (76% vs 56%; p = 0.01) and AUC values (0.983 vs 0.760; p < 0.01). CONCLUSION: Up to one-third of patients with recurrent acute pancreatitis showed exocrine functional abnormalities. Secretin-enhanced MRCP had a significantly higher yield for ductal abnormalities than did conventional MRI and should be part of the MRCP protocol for investigation of patients with recurrent acute pancreatitis.

CT Texture Analysis: Definitions, Applications, Biologic Correlates, and Challenges.

This review discusses potential oncologic and nononcologic applications of CT texture analysis ( CTTA CT texture analysis ), an emerging area of "radiomics" that extracts, analyzes, and interprets quantitative imaging features. CTTA CT texture analysis allows objective assessment of lesion and organ heterogeneity beyond what is possible with subjective visual interpretation and may reflect information about the tissue microenvironment. CTTA CT texture analysis has shown promise in lesion characterization, such as differentiating benign from malignant or more biologically aggressive lesions. Pretreatment CT texture features are associated with histopathologic correlates such as tumor grade, tumor cellular processes such as hypoxia or angiogenesis, and genetic features such as KRAS or epidermal growth factor receptor (EGFR) mutation status. In addition, and likely as a result, these CT texture features have been linked to prognosis and clinical outcomes in some tumor types. CTTA CT texture analysis has also been used to assess response to therapy, with decreases in tumor heterogeneity generally associated with pathologic response and improved outcomes. A variety of nononcologic applications of CTTA CT texture analysis are emerging, particularly quantifying fibrosis in the liver and lung. Although CTTA CT texture analysis seems to be a promising imaging biomarker, there is marked variability in methods, parameters reported, and strength of associations with biologic correlates. Before CTTA CT texture analysis can be considered for widespread clinical implementation, standardization of tumor segmentation and measurement techniques, image filtration and postprocessing techniques, and methods for mathematically handling multiple tumors and time points is needed, in addition to identification of key texture parameters among hundreds of potential candidates, continued investigation and external validation of histopathologic correlates, and structured reporting of findings. ©RSNA, 2017.

The natural history of pancreatic lipoma: Does it need observation.

BACKGROUND: Pancreatic lipomas (PL) are a rare, benign mesenchymal neoplasm. Some patients diagnosed with PL are followed radiographically or referred to a second provider, while others are not followed after incidental diagnosis. In this study we describe 74 cases of intrapancreatic lipomas from a single institution over a 12-year period to elucidate the radiologic and clinical natural history of pancreatic lipoma. METHODS: In the period from January 2001 to December 2013, we selected patients over the age of 18 diagnosed with PL based on Ultrasound, CT, and MR imaging. Clinical data were coupled with review of the radiographic image. These patients were retrospectively followed to establish the significance of PL. RESULTS: PL was identified in 0.012% of all patients undergoing cross-sectional imaging during the studied interval. Lipomas ranged in size at diagnosis from 0.1 cm to 4.8 cm. The majority of patients were asymptomatic at presentation. No patient required intervention or exhibited a change in lipoma diagnosis over a median follow up interval of 41.5 months (range 2-145). 47 patients underwent subsequent imaging with a median of two additional exams (range 2-113) over 31 months (range 1-18). 46/47 (98%) patients with subsequent images showed no discernible growth; 1/47 (2%) had a resolution of the lipoma. CONCLUSIONS: Pancreatic lipomas are rare benign mesenchymal neoplasms that exhibit stable size and morphology. They are overwhelmingly asymptomatic. The natural history of pancreatic lipoma is benign. Short-term interval observation is prudent to prove stability and help differentiate from early liposarcoma. Extensive follow-up is not likely necessary for this benign lesion.

Correlation of histogram analysis of apparent diffusion coefficient with uterine cervical pathologic finding.

OBJECTIVE: The purpose of this study was to investigate the application of histogram analysis of apparent diffusion coefficient (ADC) in characterizing pathologic features of cervical cancer and benign cervical lesions. SUBJECTS AND METHODS: This prospective study was approved by the institutional review board, and written informed consent was obtained. Seventy-three patients with cervical cancer (33-69 years old; 35 patients with International Federation of Gynecology and Obstetrics stage IB cervical cancer) and 38 patients (38-61 years old) with normal cervix or cervical benign lesions (control group) were enrolled. All patients underwent 3-T diffusion-weighted imaging (DWI) with b values of 0 and 800 s/mm(2). ADC values of the entire tumor in the patient group and the whole cervix volume in the control group were assessed. Mean ADC, median ADC, 25th and 75th percentiles of ADC, skewness, and kurtosis were calculated. Histogram parameters were compared between different pathologic features, as well as between stage IB cervical cancer and control groups. RESULTS: Mean ADC, median ADC, and 25th percentile of ADC were significantly higher for adenocarcinoma (p = 0.021, 0.006, and 0.004, respectively), and skewness was significantly higher for squamous cell carcinoma (p = 0.011). Median ADC was statistically significantly higher for well or moderately differentiated tumors (p = 0.044), and skewness was statistically significantly higher for poorly differentiated tumors (p = 0.004). No statistically significant difference of ADC histogram was observed between lymphovascular space invasion subgroups. All histogram parameters differed significantly between stage IB cervical cancer and control groups (p < 0.05). CONCLUSION: Distribution of ADCs characterized by histogram analysis may help to distinguish early-stage cervical cancer from normal cervix or cervical benign lesions and may be useful for evaluating the different pathologic features of cervical cancer.

Hematologic malignancies of the liver: spectrum of disease.

The incidence of hematologic malignancies and their extranodal manifestations is continuously increasing. Previously unsuspected hepatic involvement in hematologic malignancies such as Hodgkin disease and non-Hodgkin lymphoma, posttransplant lymphoproliferative disorder, myeloid sarcoma (chloroma), multiple myeloma, Castleman disease, and lymphohistiocytosis may be seen by radiologists. Although the imaging features of more common hepatic diseases such as hepatocellular carcinoma, metastases, and infection may overlap with those of hepatic hematologic malignancies, combining the imaging features with clinical manifestations and laboratory findings can facilitate correct diagnosis. Clinical features that suggest a hematologic neoplasm as the cause of liver lesions include a young patient (<40 years of age), no known history of cancer, abnormal bone marrow biopsy results, fever of unknown origin, and night sweats. Imaging features that suggest hematologic malignancy include hepatosplenomegaly or splenic lesions, vascular encasement by a tumor without occlusion or thrombosis, an infiltrating mass at the hepatic hilum with no biliary obstruction, and widespread adenopathy above and below the diaphragm. Familiarity with the imaging features of hepatic hematologic malignancies permits correct provisional diagnosis and may influence therapeutic management. For example, when biopsy is performed, core biopsy may be needed in addition to fine-needle aspiration so that the tissue architecture of the neoplasm can be discerned. The predominant treatment of hematologic malignancies is chemotherapy or radiation therapy rather than surgery. Online supplemental material is available for this article.

MR Imaging of the Penis and Scrotum.

Traditionally, due to its low cost, ready availability, and proved diagnostic accuracy, ultrasonography (US) has been the primary imaging modality for the evaluation of scrotal and, to a lesser extent, penile disease. However, US is limited by its relatively small useful field of view, operator dependence, and inability to provide much information on tissue characterization. Magnetic resonance (MR) imaging, with its excellent soft-tissue contrast and good spatial resolution, is increasingly being used as both a problem-solving tool in patients who have already undergone US and as a primary modality for the evaluation of suspected disease. Specifically, MR imaging can aid in differentiating between benign and malignant lesions seen at US, help define the extent of inflammatory processes or traumatic injuries, and play a vital role in locoregional staging of tumors. Consequently, it is becoming more important for radiologists to be familiar with the wide range of penile and scrotal disease entities and their MR imaging appearances. The authors review the basic anatomy of the penis and scrotum as seen at MR imaging and provide a basic protocol for penile and scrotal imaging, with emphasis on the advantages of MR imaging. Pathologic processes are organized into traumatic (including penile fracture and contusion), infectious or inflammatory (including Fournier gangrene and scrotal abscess), and neoplastic (including both benign and malignant scrotal and penile tumors) processes.

Polypoid lesions of the gallbladder: disease spectrum with pathologic correlation.

Gallbladder polyps are seen on as many as 7% of gallbladder ultrasonographic images. The differential diagnosis for a polypoid gallbladder mass is wide and includes pseudotumors, as well as benign and malignant tumors. Tumefactive sludge may be mistaken for a gallbladder polyp. Pseudotumors include cholesterol polyps, adenomyomatosis, and inflammatory polyps, and they occur in that order of frequency. The most common benign and malignant tumors are adenomas and primary adenocarcinoma, respectively. Polyp size, shape, and other ancillary imaging findings, such as a wide base, wall thickening, and coexistent gallstones, are pertinent items to report when gallbladder polyps are discovered. These findings, as well as patient age and risk factors for gallbladder cancer, guide clinical decision making. Symptomatic polyps without other cause for symptoms, an age over 50 years, and the presence of gallstones are generally considered indications for cholecystectomy. Incidentally noted pedunculated polyps smaller than 5 mm generally do not require follow-up. Polyps that are 6-10 mm require follow-up, although neither the frequency nor the length of follow-up has been established. Polyps that are larger than 10 mm are typically excised, although lower size thresholds for cholecystectomy may be considered for patients with increased risk for gallbladder carcinoma, such as patients with primary sclerosing cholangitis.

The Presence of Portal Vein Thrombosis Alters the Classic Enhancement Associated with Diagnosis of Hepatocellular Carcinoma.

AIMS: To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be associated with more advanced disease. We characterized the incidence and imaging characteristics of patients diagnosed with hepatocellular carcinoma in a cohort of patients with PVT compared with those without PVT. METHODS: This is a single-center retrospective study of a subset of HCC patients who underwent dynamic imaging for HCC screening and were found to have PVT. Data abstracted included demographic data, TNM stage, number/type of scans, AFP level, MELD score, and time to diagnosis. RESULTS: Eighty-two patients newly diagnosed with HCC on screening were reviewed, of which 37 % (30/82) were found to have portal vein thrombosis. Patients with PVT had higher rates of atypical imaging associated with HCC compared with those without PVT (83 vs 56 %, p = 0.01) and had lower rates of portal venous washout (23 % vs 50 %, p = 0.018). Patients with PVT and HCC were also diagnosed at later TNM stage than those without PVT (70 vs 23 %, p < 0.001) and were significantly less likely to receive orthotopic liver transplant (3.6 vs 42 %, p < 0.001). Fourteen patients had preexisting PV clot without HCC; 16 developed PVT during screening or at diagnosis. Those with preexisting PVT were older (63. vs 55 years) and had higher rates of diagnosis of HCC using MRI (79 vs 21 % with CT, p = 0.01), compared with those without preexisting PVT. CONCLUSION: The presence of PVT found on dynamic imaging was associated with advanced stage of HCC at the time of diagnosis. Clinicians should have a high suspicion for HCC diagnosis in new liver lesions with atypical enhancement in the setting of PVT. In this setting, MRI was more frequently associated with HCC diagnosis.

Value of gadoxetate biliary transit time in determining hepatocyte function.

OBJECTIVE: To determine if transit time for excretion of gadoxetate into major bile ducts and duodenum correlates with clinical models of hepatocellular function. METHODS: This retrospective research was approved by the Institutional Review Board with waiver of informed consent. Search of the radiology database from January 1, 2013 to March 4, 2014 revealed 84 patients with chronic liver disease (65 males, mean age 47 years). Eighteen control subjects with no known liver disease or risk factors were also enrolled for analysis (9 males, mean age 43 years). MRI was performed with hepatobiliary phases at 10, 15, 20, and 25 min after injection of 0.025 mmol/kg of gadoxetate (Primovist, Bayer HealthCare, Shanghai, China). The time of excreted contrast appearing in the biliary tree and in the duodenum was recorded. Linear trend analysis was performed to determine the relationship between excretion time and hepatic function. RESULTS: The patient cohort was stratified by Child-Pugh classification (A, B, and C with n = 53, 27, and 4, respectively). Arrival of gadoxetate in the gall bladder at 10-min hepatobiliary phase was seen in 87% of control group and 45% of Child-Pugh A group (p = 0.02). There was no difference between these groups for later hepatobiliary phases. The arrival of biliary contrast in the right hepatic duct, common bile duct, and gall bladder were significantly earlier in the Child-Pugh A group compared to the Child-Pugh B/C group at all hepatobiliary phases after 10 min (p < 0.05). Linear trend analysis showed that biliary transit times were significantly delayed with worsening liver function (p = 0.01). There was no difference in entry time of gadoxetate into the duodenum between the normal, Child-Pugh A, and Child-Pugh B/C groups. CONCLUSIONS: The transit time for gadoxetate to appear in extrahepatic duct is a reasonable indicator of liver function, and may be included in radiology reports. The appearance in the duodenum, however, may depend on factors other than liver function, such as the physiology of the gallbladder and sphincter of Oddi.

Hematologic malignancies of the pancreas.

Hematologic malignancies are relatively uncommon neoplasms of abdominal soft tissue. This article discusses the clinical and imaging features of pancreatic lymphoma, pancreatic extraosseous multiple myeloma, granulocytic sarcoma (chloroma), posttransplant lymphoproliferative disorder, and Castleman disease. The combination of imaging findings and the appropriate clinical presentation should allow the radiologist to raise a provisional diagnosis of hematologic malignancy.