Invasive Intraductal Papillary Mucinous Neoplasms: CT Features of Colloid Carcinoma Versus Tubular Adenocarcinoma of the Pancreas.

OBJECTIVE. The purpose of this study is to compare the CT features of colloid carcinoma and tubular adenocarcinoma of the pancreas arising in association with intraductal papillary mucinous neoplasms (IPMNs). MATERIALS AND METHODS. The preoperative CT images of 85 patients with histopathologically proven IPMNs and associated invasive adenocarcinoma located next to each other were retrospectively reviewed. Twenty-nine patients (34.1%; 19 men and 10 women; mean [± SD] age, 68.0 ± 9.5 years) had invasive colloid carcinoma, and 56 patients (65.9%; 31 men and 25 women; mean age, 70.8 ± 10.6 years) had invasive tubular adenocarcinoma. We compared the following CT features between the two groups: IPMN type, main pancreatic duct (MPD) and common bile duct diameters, diameter and characteristics of the largest cystic lesion for branch duct and mixed-type IPMNs, presence of an extracystic or extraductal solid mass next to the cystic lesion or MPD, morphologic features of the upstream MPD in relation to the cystic lesion or solid mass, and presence of a fistula to the adjacent organs. RESULTS. An MPD size of 9.5 mm or greater, a largest cystic lesion diameter of 28 mm or greater, location in the head or neck, septation, calcification, presence of a mural nodule(s) within a cystic lesion or MPD, and presence of a fistula were all more commonly associated with colloid carcinoma. In contrast, presence of an extracystic or extraductal solid mass and an abrupt change in the caliber of the dilated MPD were associated with tubular adenocarcinoma. The best CT feature for differentiating between the two groups was the morphologic features of the upstream MPD in relation to the cystic lesion or solid mass (sensitivity, 81.3%; specificity, 92.3%). CONCLUSION. Preoperative CT is helpful in differentiating two types of invasive carcinoma arising in association with IPMNs. These findings are clinically important because prognosis is better for colloid carcinoma than for tubular adenocarcinoma.

A combination of molecular markers and clinical features improve the classification of pancreatic cysts.

BACKGROUND & AIMS: The management of pancreatic cysts poses challenges to both patients and their physicians. We investigated whether a combination of molecular markers and clinical information could improve the classification of pancreatic cysts and management of patients. METHODS: We performed a multi-center, retrospective study of 130 patients with resected pancreatic cystic neoplasms (12 serous cystadenomas, 10 solid pseudopapillary neoplasms, 12 mucinous cystic neoplasms, and 96 intraductal papillary mucinous neoplasms). Cyst fluid was analyzed to identify subtle mutations in genes known to be mutated in pancreatic cysts (BRAF, CDKN2A, CTNNB1, GNAS, KRAS, NRAS, PIK3CA, RNF43, SMAD4, TP53, and VHL); to identify loss of heterozygozity at CDKN2A, RNF43, SMAD4, TP53, and VHL tumor suppressor loci; and to identify aneuploidy. The analyses were performed using specialized technologies for implementing and interpreting massively parallel sequencing data acquisition. An algorithm was used to select markers that could classify cyst type and grade. The accuracy of the molecular markers was compared with that of clinical markers and a combination of molecular and clinical markers. RESULTS: We identified molecular markers and clinical features that classified cyst type with 90%-100% sensitivity and 92%-98% specificity. The molecular marker panel correctly identified 67 of the 74 patients who did not require surgery and could, therefore, reduce the number of unnecessary operations by 91%. CONCLUSIONS: We identified a panel of molecular markers and clinical features that show promise for the accurate classification of cystic neoplasms of the pancreas and identification of cysts that require surgery.

Phase 2 multi-institutional trial evaluating gemcitabine and stereotactic body radiotherapy for patients with locally advanced unresectable pancreatic adenocarcinoma.

BACKGROUND: This phase 2 multi-institutional study was designed to determine whether gemcitabine (GEM) with fractionated stereotactic body radiotherapy (SBRT) results in acceptable late grade 2 to 4 gastrointestinal toxicity when compared with a prior trial of GEM with single-fraction SBRT in patients with locally advanced pancreatic cancer (LAPC). METHODS: A total of 49 patients with LAPC received up to 3 doses of GEM (1000 mg/m(2)) followed by a 1-week break and SBRT (33.0 gray [Gy] in 5 fractions). After SBRT, patients continued to receive GEM until disease progression or toxicity. Toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0] and the Radiation Therapy Oncology Group radiation morbidity scoring criteria. Patients completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (QLQ-C30) and pancreatic cancer-specific QLQ-PAN26 module before SBRT and at 4 weeks and 4 months after SBRT. RESULTS: The median follow-up was 13.9 months (range, 3.9-45.2 months). The median age of the patients was 67 years and 84% had tumors of the pancreatic head. Rates of acute and late (primary endpoint) grade ≥ 2 gastritis, fistula, enteritis, or ulcer toxicities were 2% and 11%, respectively. QLQ-C30 global quality of life scores remained stable from baseline to after SBRT (67 at baseline, median change of 0 at both follow-ups; P>.05 for both). Patients reported a significant improvement in pancreatic pain (P = .001) 4 weeks after SBRT on the QLQ-PAN26 questionnaire. The median plasma carbohydrate antigen 19-9 (CA 19-9) level was reduced after SBRT (median time after SBRT, 4.2 weeks; 220 U/mL vs 62 U/mL [P<.001]). The median overall survival was 13.9 months (95% confidence interval, 10.2 months-16.7 months). Freedom from local disease progression at 1 year was 78%. Four patients (8%) underwent margin-negative and lymph node-negative surgical resections. CONCLUSIONS: Fractionated SBRT with GEM results in minimal acute and late gastrointestinal toxicity. Future studies should incorporate SBRT with more aggressive multiagent chemotherapy.

The Role of Stereotactic Body Radiation Therapy for Pancreatic Cancer: A Single-Institution Experience.

BACKGROUND: Stereotactic body radiation therapy (SBRT) is a promising option for patients with pancreatic cancer (PCA); however, limited data support its efficacy. This study reviews our institutional experience of SBRT in the treatment of locally advanced (LAPC) and borderline resectable (BRPC) PCA. METHODS: Charts of all PCA patients receiving SBRT at our institution from 2010 to 2014 were reviewed. Most patients received pre-SBRT chemotherapy. Primary endpoints included overall survival (OS) and local progression-free survival (LPFS). Patients received a total dose of 25-33 Gy in five fractions. RESULTS: A total of 88 patients were included in the analysis, 74 with LAPC and 14 with BRPC. The median age at diagnosis was 67.2 years, and median follow-up from date of diagnosis for LAPC and BRPC patients was 14.5 and 10.3 months, respectively. Median OS from date of diagnosis was 18.4 months (LAPC, 18.4 mo; BRPC, 14.4 mo) and median PFS was 9.8 months (95 % CI 8.0-12.3). Acute toxicity was minimal with only three patients (3.4 %) experiencing acute grade ≥3 toxicity. Late grade ≥2 gastrointestinal toxicity was seen in five patients (5.7 %). Of the 19 patients (21.6 %) who underwent surgery, 79 % were LAPC patients and 84 % had margin-negative resections. CONCLUSIONS: Chemotherapy followed by SBRT in patients with LAPC and BRPC resulted in minimal acute and late toxicity. A large proportion of patients underwent surgical resection despite limited radiographic response to therapy. Further refinements in the integration of chemotherapy, SBRT, and surgery might offer additional advancements toward optimizing patient outcomes.

Abdominal CT predictors of fibrosis in patients with chronic pancreatitis undergoing surgery.

OBJECTIVE: To determine which abdominal CT findings predict severe fibrosis and post-operative pain relief in chronic pancreatitis (CP). METHODS: Pre-operative abdominal CTs of 66 patients (mean age 52 ± 12 years, 53 % males) with painful CP who underwent the Whipple procedure (n = 32), Frey procedure (n = 32) or pancreatic head biopsy (n = 2), between 1/2003-3/2014, were evaluated. CT was evaluated for parenchymal calcifications, intraductal calculi, main pancreatic duct dilation (>5 mm), main pancreatic duct stricture, and abnormal side branch(es). The surgical histopathology was graded for fibrosis. CT findings were evaluated as predictors of severe fibrosis and post-operative pain relief using regression and area under receiver operating curve (AUC) analysis. RESULTS: Thirty-eight (58 %) patients had severe fibrosis. Parenchymal calcification(s) were an independent predictor of severe fibrosis (p = 0.03), and post-operative pain relief over a mean follow-up of 1-year (p = 0.04). Presence of >10 parenchymal calcifications had higher predictive accuracy for severe fibrosis than 1-10 parenchymal calcification(s) (AUC 0.88 vs. 0.59, p = 0.003). The predictive accuracy of >10 versus 1-10 parenchymal calcifications increased after adjusting for all other CT findings (AUC 0.89 vs. 0.63, p = 0.01). CONCLUSION: Parenchymal calcification(s) independently predict severe fibrosis and are significantly associated with post-operative pain relief in CP. The presence of >10 parenchymal calcifications is a better predictor of severe fibrosis than 1-10 parenchymal calcification(s). KEY POINTS: • Parenchymal calcifications in chronic pancreatitis independently predict post-operative pain relief • Intraductal calculi and MPD dilation are not associated with post-operative pain relief • Better patient selection for pancreatic resection surgery in painful chronic pancreatitis.

CT Detection of Symptomatic and Asymptomatic Meckel Diverticulum.

OBJECTIVE: The objective of our study was to determine how often symptomatic Meckel diverticulum and asymptomatic Meckel diverticulum are detected on CT in patients with known Meckel diverticulum and to evaluate factors that influence detection. MATERIALS AND METHODS: A total of 85 CT examinations of 40 patients (eight pediatric patients and 32 adult patients; 29 male patients and 11 female patients; average age, 46.2 ± 23.7 [SD] years) with a pathologic diagnosis of Meckel diverticulum were retrospectively evaluated. These patients included 26 adult patients with incidentally found asymptomatic Meckel diverticulum and 14 patients (eight pediatric and six adult patients) with symptomatic Meckel diverticulum. The CT technical factors and patients' morphologic factors were compared with the detection of Meckel diverticulum using mixed-effect logistic regression models. RESULTS: Meckel diverticulum was detected on at least one CT examination in eight of 14 (57.1%) symptomatic patients (two of four patients with bleeding, two of six patients with small-bowel obstruction, two of two patients with acute diverticulitis, one of one patient with incisional hernia, and one of one patient with inverted Meckel diverticulum) and in 13 of 23 (56.5%) total CT examinations. Asymptomatic Meckel diverticulum was detected on at least one CT examination in 11 of 26 (42.3%) patients and in 16 of 62 (25.8%) total CT examinations. The amount of peritoneal fat was related to the detection of Meckel diverticula (p = 0.02). Although not statistically significant, the subjective quality of axial CT (p = 0.05) tended to be related to detection, whereas the use of IV (p = 0.59) or positive oral (p = 0.41) contrast material was unrelated to detection. In the original CT reports, none of the asymptomatic cases of Meckel diverticulum was prospectively detected, whereas Meckel diverticulum was detected or mentioned as a possibility in 64% of the symptomatic cases. CONCLUSION: In patients with known Meckel diverticulum, CT can detect Meckel diverticulum in up to 47.5% of all patients. Meckel diverticulum is more commonly detected in symptomatic patients than in asymptomatic patients, and detection is related to the amount of peritoneal fat.

Impact of the time interval between MDCT imaging and surgery on the accuracy of identifying metastatic disease in patients with pancreatic cancer.

OBJECTIVE: Pancreatic adenocarcinoma is a rapidly progressive malignancy characterized by its tendency for early metastatic spread. MDCT is the primary diagnostic modality for the preoperative staging of patients with pancreatic cancer, with an accuracy established in multiple studies. However, for a variety of reasons, there is often a prolonged interval between staging MDCT and the surgical intervention. This study examines the relationship between the interval between imaging and surgery and the accuracy of MDCT in determining the presence or absence of metastatic disease at surgery in patients with pancreatic cancer. MATERIALS AND METHODS: Patients were identified who had undergone surgery for pancreatic cancer at our institution with a dedicated preoperative pancreas-protocol MDCT performed in our department. Findings from the preoperative MDCT report were correlated with the operative findings, as well as the time between imaging and surgery. RESULTS: Two hundred ninety-two MDCT scans were performed on 256 patients who underwent exploration for pancreatic adenocarcinoma. The patients had a median age of 67 years (range, 30-95 years), and 51.6% (132/256) were male. The median time between MDCT and surgical exploration was 15.5 days (range, 1-198 days). MDCT correctly predicted the absence of metastatic disease at surgery in 233 of 274 (85.0%) studies. MDCT was more accurate in predicting the absence of metastatic disease if the study was performed within 25 days of surgery than it was if the study was performed within more than 25 days of surgery (89.3% vs 77.0%; p = 0.0097). Furthermore, regression models showed that the negative predictive value of a given MDCT significantly decreased after approximately 4 weeks. CONCLUSION: MDCT is an accurate method to stage patients with pancreatic cancer, but its accuracy in excluding distant metastatic disease depreciates over time. Patients should undergo a repeat MDCT within 25 days of any planned definitive operative intervention for pancreatic cancer to avoid unexpectedly finding metastatic disease at surgery.

Diagnostic performance of multidetector computed tomography in distinguishing unilateral from bilateral abnormalities in primary hyperaldosteronism: comparison of multidetector computed tomography with adrenal vein sampling.

OBJECTIVE: The management of patients with primary hyperaldosteronism (PH) varies depending on whether the unregulated aldosterone secretion localizes to a single unilateral adrenal gland, traditionally determined using adrenal vein sampling (AVS). This study seeks to determine if the performance of multidetector computed tomography (MDCT) examinations performed using the latest scanner technology can reasonably match the results of AVS, and potentially avoid AVS in some patients. MATERIALS AND METHODS: Computed tomographic scans in 56 patients with PH were independently reviewed by 2 radiologists for the presence of adrenal nodules and qualitative adrenal thickening. Results were correlated with AVS results. RESULTS: Of 35 patients with MDCT evidence of unilateral nodules, the imaging findings correctly predicted AVS localization in only 23 (65.7%) cases. When stratified by size, MDCT was accurate in only 71.4% of cases for nodules measuring 10 mm or less, and only 55.0% of cases for nodules measuring 11 to 20 mm. Of the 12 cases where MDCT did not correctly localize, AVS localized to the contralateral adrenal gland in 4 cases, whereas AVS suggested no lateralization in 8 cases. In patients with normal bilateral adrenal glands on MDCT, 2/7 (28.6%) of cases demonstrated unilateral localization on AVS, and in patients with bilateral adrenal nodules, only 3/14 (21.4%) did not demonstrate lateralization on AVS. CONCLUSIONS: Multidetector computed tomography, even when performed with the latest generation of MDCT scanners, does not offer sufficient diagnostic accuracy to replace AVS in patients with PH.

Preliminary data using computed tomography texture analysis for the classification of hypervascular liver lesions: generation of a predictive model on the basis of quantitative spatial frequency measurements--a work in progress.

OBJECTIVE: Computed tomography texture analysis (CTTA) is a method of quantifying lesion heterogeneity based on distribution of pixel intensities within a region of interest. This study investigates the ability of CTTA to distinguish different hypervascular liver lesions and compares CTTA parameters by creating a proof-of-concept model to distinguish between different lesions. METHODS: Following institutional review board approval, CTTA software (TexRAD Ltd) was used to retrospectively analyze 17 cases of focal nodular hyperplasia, 19 hepatic adenomas, 25 hepatocellular carcinomas, and 19 cases of normal liver parenchyma using arterial phase scans. Two radiologists read the same image series used by the CTTA software and reported their best guess diagnosis. Computed tomography texture analysis parameters were computed from regions of interest using spatial band-pass filters to quantify heterogeneity. Random-forest method was used to construct a predictive model from these parameters, and a separate regression model was created using a subset of parameters. RESULTS: The random-forest model successfully distinguished the 3 lesion types and normal liver with predicted classification performance accuracy for 91.2% for adenoma, 94.4% for focal nodular hyperplasia, and 98.6% for hepatocellular carcinoma. This error prediction was generated using a subset of data points not used in generation of the model, but not on discrete prospective cases. In contrast, the 2 human readers using the same image series data analyzed by the CTTA software had lower accuracies, of 72.2% and 65.6%, respectively. The explicit regression model with a subset of image parameters had intermediate overall accuracy of 84.9%. CONCLUSIONS: Computed tomography texture analysis may prove valuable in lesion characterization. Differentiation between common hypervascular lesion types could be aided by the judicious incorporation of texture parameters into clinical analysis.

Role of a multidisciplinary clinic in the management of patients with pancreatic cysts: a single-center cohort study.

BACKGROUND: Incidental pancreatic cysts are common, a small number of which are premalignant or malignant. Multidisciplinary care has been shown to alter management and improve outcomes in many types of cancers, but its role has not been examined in patients with pancreatic cysts. We assessed the effect of a multidisciplinary pancreatic cyst clinic (MPCC) on the diagnosis and management of patients with pancreatic cysts. METHODS: The referring institution and MPCC diagnosis and management plan were recorded. Patient were placed into one of five categories-no, low, intermediate, or high risk of malignancy within the cyst, and malignant cyst-on the basis of their diagnosis. Patients were assigned one of four management options: surveillance, surgical resection, further evaluation, or discharge with no further follow-up required. The MPCC was deemed to have altered patient care if the patient was assigned a different risk or management category after the MPCC review. RESULTS: Referring institution records were available for 262 patients (198 women; mean age 62.7 years), with data on risk category available in 138 patients and management category in 225. The most common diagnosis was branch duct intraductal papillary mucinous neoplasm. MPCC review altered the risk category in 11 (8.0%) of 138 patients. The management category was altered in 68 (30.2%) of 225 patients. Management was increased in 52 patients, including 22 patients who were recommended surgical resection. Management was decreased in 16 patients, including 10 who had their recommendation changed from surgery to surveillance. CONCLUSIONS: MPCC is helpful and alters the management over 30% of patients.

Bladder malignancies on CT: the underrated role of CT in diagnosis.

OBJECTIVE: The purpose of this article is to review the utility of CT in diagnosing bladder malignancies, CT protocol options that may improve the conspicuity of bladder tumors, suggestive imaging features, and potential mimics. CONCLUSION: Although evaluation of the bladder has traditionally been considered purely the realm of cystoscopy, many bladder tumors can be identified with CT. However, diagnosis requires optimization of CT technique and close attention to a number of potentially subtle findings.

Abnormalities of the distal common bile duct and ampulla: diagnostic approach and differential diagnosis using multiplanar reformations and 3D imaging.

OBJECTIVE: The distal common bile duct (CBD) and ampulla are extremely difficult sites to evaluate on CT. This article seeks to provide the reader with a framework and algorithmic approach to the evaluation of abnormalities involving the distal CBD and ampulla, including an emphasis on the use of multiplanar reformations and 3D imaging, the morphologic features on CT that suggest the presence of malignancy, and a differential diagnosis for abnormalities in this location. CONCLUSION: In our experience, both the distal CBD and ampulla are common sites of missed diagnoses for radiologists. Avoiding mistakes in interpreting imaging findings in this location requires a systematic approach especially in the setting of unexplained biliary ductal dilatation. Rather than simply suggesting that MRCP or ERCP be performed for the ultimate diagnosis, radiologists can perform a careful CT evaluation using multiplanar reformations and 3D imaging to determine the correct diagnosis prospectively. A timely and correct diagnosis is imperative because lesions in the ampulla and CBD can be very aggressive despite their small size.

Focal nodular hyperplasia within accessory liver: imaging findings at computed tomography and magnetic resonance imaging.

Accessory liver tissue is a rare but probably underreported entity that may harbor the same spectrum of pathology as that of the parent organ. The rarity and aberrant locations of such lesions cause confusion and may lower diagnostic confidence despite otherwise classic radiographic appearances. Focal nodular hyperplasia (FNH) is the most common non-hemangiomatous benign hepatic tumor, but to our knowledge, ectopic FNH has been reported only once before in the gastroenterology literature. We present the first case of ectopic FNH in the radiology literature.

Features suggestive of gallbladder malignancy: analysis of T1, T2, and T3 tumors on cross-sectional imaging.

OBJECTIVES: Gallbladder cancer carries an extremely high mortality rate, with a 5-year survival rate as low as 12%. Survival is dependent on the diagnosis of these tumors in their earliest stages. This study sought to describe the clinical and imaging features of stages T1, T2, and T3 gallbladder tumors and to illustrate features that may allow radiologists to make an early diagnosis. MATERIALS AND METHODS: After approval from the institutional review board, a search of the pathology department database yielded 18 patients with surgically proven T1, T2, and T3 gallbladder cancers with available preoperative computed tomography (CT) or magnetic resonance imaging. The imaging was reviewed for lesional morphology (focal polyploid mass, focal wall thickening, circumferential wall thickening), enhancement characteristics, liver invasion, locoregional lymphadenopathy, and distant metastatic disease. The electronic medical record was also searched for demographic information and clinical presentation. RESULTS: There were 10 women and 8 men with a mean age of 69 years. Virtually all patients were symptomatic, with most patients demonstrating symptoms suggestive of underlying malignancy (including jaundice, weight loss, and chronic abdominal pain). Tumors on CT and MRI included 6 polyploid masses, 9 tumors with focal wall thickening, and 3 with circumferential wall thickening. The mean attenuation of those tumors imaged with CT was 59.4 Hounsfield units (HUs) on the arterial phase and 86.5 HUs on the venous phase, with a mean increase in Hounsfield attenuation between the arterial and venous phases of 28.2 HUs. Twelve of the 18 patients were correctly diagnosed prospectively on CT. CONCLUSIONS: The imaging findings of gallbladder cancer can be subtle, regardless of whether the tumor presents as a discrete mass, focal wall thickening, or circumferential diffuse wall thickening, and radiologists should be aware of the wide range of different possible appearances. Moreover, the vast majority of these patients had clinical symptoms suggestive of an underlying malignancy, and this should precipitate a careful evaluation of the gallbladder in all such cases.

Mycotic aneurysms: a critical diagnosis in the emergency setting.

This pictorial essay reviews the pathophysiology and causes of mycotic aneurysms, their typical imaging appearances, mimics of mycotic aneurysms on CT, and treatment options. Correctly diagnosing mycotic aneurysms is critical for patient morbidity and mortality, as infected aneurysms are at extremely high risk of rapid growth and sudden rupture. The presence of a constellation of suggestive imaging features, as well as concerning patient symptomatology, should raise the possibility of a mycotic aneurysm.

MDCT and CT angiography evaluation of rectal bleeding: the role of volume visualization.

OBJECTIVE: This article reviews several different causes of rectal bleeding and the role of MDCT in diagnosis. CONCLUSION: Although colonoscopy remains the first-line modality for the diagnosis of lower gastrointestinal tract bleeding, colonoscopy may not be possible for unstable patients, and moreover, even for patients who undergo colonoscopy, the examination may still fail to diagnose a cause for bleeding. MDCT with CT angiography and 3D mapping now offers a valuable option for diagnosis, not only for patients whose colonoscopy findings were negative, but also as a first-line screening modality for patients with active bleeding and hemodynamic instability. This article reviews the valuable role of MDCT in the diagnosis of multiple different causes of rectal bleeding, including rectal vascular malformations, rectal varices, ischemic colitis, stercoral colitis, inflammatory bowel disease, radiation proctopathy, infectious colitis, and rectal cancer.

MDCT evaluation of ureteral tumors: advantages of 3D reconstruction and volume visualization.

OBJECTIVE: This article reviews the use of CT urography in diagnosing ureteral transitional cell carcinomas, different CT urography protocols, CT findings suggestive of ureteral malignancy, and the importance of 3D reconstructions. CONCLUSION: The ureters can be problematic to evaluate on CT, partly because of difficulties in obtaining adequate ureteral distention and opacification. Proper diagnosis hinges not only on appropriate interpretation of the axial images but also on the utilization of a 3D technique (volume rendering or maximum intensity projection) as an ancillary tool.

CT after pancreaticoduodenectomy: spectrum of normal findings and complications.

OBJECTIVE: The purpose of this article is to discuss the normal findings and complications after pancreaticoduodenectomy. The Whipple procedure is associated with a set of common complications, including pancreatic fistula, postsurgical hemorrhage, postoperative pancreatitis, portomesenteric venous thrombosis, hepatic infarction, delayed gastric emptying, and anastomotic strictures. CONCLUSION: Appropriate diagnosis of these complications is contingent on an understanding of the surgical anatomy, normal postoperative imaging appearance in both the immediate postoperative and chronic settings, and typical CT appearance of each of these complications.

Groove pancreatitis: spectrum of imaging findings and radiology-pathology correlation.

OBJECTIVE: Groove pancreatitis is a rare form of chronic pancreatitis affecting the "groove" between the pancreatic head, duodenum, and common bile duct. The exact cause is unknown, although there are strong associations with long-term alcohol abuse, functional obstruction of the duct of Santorini, and Brunner gland hyperplasia. CONCLUSION: Unfortunately, differentiating groove pancreatitis from malignancy on the basis of imaging features, clinical presentation, or laboratory markers can be extraordinarily difficult, and the vast majority of these patients ultimately undergo a pancreaticoduodenectomy (Whipple procedure) because of an inability to completely exclude malignancy. In certain cases, however, the imaging features on CT and MRI can allow the radiologist to prospectively suggest the correct diagnosis.

Chromophobe renal cell carcinoma: multiphase MDCT enhancement patterns and morphologic features.

OBJECTIVE: The purpose of this investigation is to retrospectively describe morphologic features, enhancement characteristics, and clinical outcomes in a series of pathologically proven chromophobe renal cell carcinomas (RCCs). MATERIALS AND METHODS: Thirty-five patients who were imaged at a single institution between 2005 and 2012 with pathologically proven chromophobe RCC were identified, all of whom underwent preoperative renal protocol CT (unenhanced, arterial, venous, and delayed images). The morphologic characteristics of each tumor (e.g., necrosis, tumor composition, and calcification), as well as attenuation values (in Hounsfield units) of the tumor, aorta, inferior vena cava, and kidney were evaluated by a board-certified radiologist. In addition, information regarding patient demographics and survival was obtained by a separate radiologist from the electronic medical record. RESULTS: Sixty percent of the patients were men, with a mean age of 60.2 years. Forty-six percent of cases were incidentally identified, without patient symptoms. None of the patients had evidence of distant metastatic disease, either on initial staging CT or over the course of follow-up (mean, 2.0 years). Mean maximal tumor diameter was 5.24 cm. Forty-six percent of tumors were homogeneous, 85% of lesions were either completely solid or mostly solid, 14% showed calcifications, and 34% showed a central scar or necrosis. Mean maximum attenuation values were 87.9 HU (arterial phase), 83.9 HU (venous phase), and 60.6 HU (delayed phase), with an average delayed washout of 31%. Tumor-to-cortex ratios for the three enhanced phases were 0.59, 0.48, and 0.50, respectively. CONCLUSION: Chromophobe RCCs were found to have a wider variability of CT features than previously reported, although they do have a greater propensity for homogeneity and the presence of a central scar or necrosis. Their enhancement characteristics fall in between those of clear cell and papillary RCC, although there is considerable overlap.