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.

Upper and Lower Tract Urothelial Imaging Using Computed Tomography Urography.

Computed tomography (CT) urography is the best noninvasive method of evaluating the upper urinary tract for urothelial malignancies. However, the utility of CT urography is heavily contingent on the use of proper image acquisition protocols. This article focuses on the appropriate protocols for optimizing CT urography acquisitions, including contrast administration and the timing of imaging acquisitions, as well as the use of ancillary techniques to increase collecting system distention. In addition, imaging findings are discussed that should raise concern for urothelial carcinoma at each of the 3 segments of the urinary tract: the intrarenal collecting systems, ureters, and bladder.

CT angiography and 3D imaging in aortoiliac occlusive disease: collateral pathways in Leriche syndrome.

Collateral pathways in aortoiliac occlusive disease are essential for arterial blood flow to the abdomen, pelvis, and lower extremities. These pathways can be broadly divided into systemic-systemic, visceral-visceral, and systemic-visceral collateral networks. MDCT angiography is the most commonly used modality for the diagnostic evaluation of patients with aortoiliac occlusive disease, allowing excellent evaluation of stenotic arterial segments, as well as beautifully illustrating resulting collateral pathways (particularly when utilizing 3D reconstruction techniques). This article seeks to familiarize radiologists with the most common patterns of aortoiliac occlusion and associated arterial collateral pathways utilizing CT angiography.

Upper and Lower Tract Urothelial Imaging Using Computed Tomography Urography.

Computed tomography (CT) urography is the best noninvasive method of evaluating the upper urinary tract for urothelial malignancies. However, the utility of CT urography is heavily contingent on the use of proper image acquisition protocols. This article focuses on the appropriate protocols for optimizing CT urography acquisitions, including contrast administration and the timing of imaging acquisitions, as well as the use of ancillary techniques to increase collecting system distention. In addition, imaging findings are discussed that should raise concern for urothelial carcinoma at each of the 3 segments of the urinary tract: the intrarenal collecting systems, ureters, and bladder.

A novel approach for selecting combination clinical markers of pathology applied to a large retrospective cohort of surgically resected pancreatic cysts.

OBJECTIVE: Our objective was to develop an approach for selecting combinatorial markers of pathology from diverse clinical data types. We demonstrate this approach on the problem of pancreatic cyst classification. MATERIALS AND METHODS: We analyzed 1026 patients with surgically resected pancreatic cysts, comprising 584 intraductal papillary mucinous neoplasms, 332 serous cystadenomas, 78 mucinous cystic neoplasms, and 42 solid-pseudopapillary neoplasms. To derive optimal markers for cyst classification from the preoperative clinical and radiological data, we developed a statistical approach for combining any number of categorical, dichotomous, or continuous-valued clinical parameters into individual predictors of pathology. The approach is unbiased and statistically rigorous. Millions of feature combinations were tested using 10-fold cross-validation, and the most informative features were validated in an independent cohort of 130 patients with surgically resected pancreatic cysts. RESULTS: We identified combinatorial clinical markers that classified serous cystadenomas with 95% sensitivity and 83% specificity; solid-pseudopapillary neoplasms with 89% sensitivity and 86% specificity; mucinous cystic neoplasms with 91% sensitivity and 83% specificity; and intraductal papillary mucinous neoplasms with 94% sensitivity and 90% specificity. No individual features were as accurate as the combination markers. We further validated these combinatorial markers on an independent cohort of 130 pancreatic cysts, and achieved high and well-balanced accuracies. Overall sensitivity and specificity for identifying patients requiring surgical resection was 84% and 81%, respectively. CONCLUSIONS: Our approach identified combinatorial markers for pancreatic cyst classification that had improved performance relative to the individual features they comprise. In principle, this approach can be applied to any clinical dataset comprising dichotomous, categorical, and continuous-valued parameters.

An algorithmic approach to CT of pulmonary arterial disorders.

A broad spectrum of pulmonary arterial disorders can be diagnosed on computed tomography (CT). Comprehensive evaluation of the pulmonary arteries requires careful assessment of their configuration, patency, and size. This article presents an organized approach to pulmonary arterial disorders on CT, with particular attention to characteristic CT findings that aid in accurate diagnosis and proper management.

Multidetector CT imaging of the pancreatic groove: differentiating carcinomas from paraduodenal pancreatitis.

OBJECTIVE: This study aims to identify multidetector row CT (MDCT) findings that differentiate paraduodenal pancreatitis (PDP) from groove carcinomas (GC). METHODS: Two radiologists retrospectively reviewed various imaging features on pancreas protocol CT scans of 8 PDP and 8 GC patients. Two-tailed Fisher's Exact Test was used for statistical analysis. RESULTS: MDCT findings correlating with PDP included benign common bile duct morphology (P<.01), duodenal wall thickening (P<.05), and cystic groove lesions (P<.01). A statistical difference in gastroduodenal artery (GDA) encasement was not observed (P=.119). CONCLUSIONS: There are several MDCT findings that favor PDP over GC. However, presence of GDA encasement is not a reliable distinguishing feature.

Computed Tomography Angiography of the Small Bowel and Mesentery.

Multidetector computed tomography (MDCT) has largely supplanted other available radiologic modalities in the evaluation of a wide variety of different vascular and inflammatory abnormalities of the small bowel, with computed tomography angiography (CTA) playing a major role in the diagnostic efficacy of MDCT for these diseases. Improvements in CTA imaging have proved particularly valuable in the evaluation of small bowel vascular and inflammatory disorders, diagnoses in which arterial phase images might be able to offer greater information than standard venous phase imaging. This article details the MDCT imaging findings of several small bowel vascular and inflammatory disorders.

Role of computed tomography angiography in detection and staging of small bowel carcinoid tumors.

Small-bowel carcinoid tumors are the most common form (42%) of gastrointestinal carcinoids, which by themselves comprise 70% of neuroendocrine tumors. Although primary small bowel neoplasms are overall rare (3%-6% of all gastrointestinal neoplasms), carcinoids still represent the second most common (20%-30%) primary small-bowel malignancy after small bowel adenocarcinoma. Their imaging evaluation is often challenging. State-of-the-art high-resolution multiphasic computed tomography together with advanced postprocessing methods provides an excellent tool for their depiction. The manifold interactive parameter choices however require knowledge of when to use which technique. Here, we discuss the imaging appearance and evaluation of duodenal, jejunal and ileal carcinoid tumors, including the imaging features of the primary tumor, locoregional mesenteric nodal metastases, and distant metastatic disease. A protocol for optimal lesion detection is presented, including the use of computed tomography enterography, volume acquisition, computed tomography angiography and three-dimensional mapping. Imaging findings are illustrated with a series of challenging cases which illustrate the spectrum of possible disease in the small bowel and mesentery, the range of possible appearances in the bowel itself on multiphase data and extraluminal findings such as the desmoplastic reaction in mesentery and hypervascular liver metastases. Typical imaging pitfalls and pearls are illustrated.

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.

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.