Computed tomography features of acinar cell carcinoma of the pancreas.

PURPOSE: To report the computed tomography (CT) features of pancreatic acinar cell carcinoma (ACC) and identify CT features that may help discriminate between pancreatic ACC and pancreatic ductal adenocarcinoma (PDA). MATERIALS AND METHODS: The CT examinations of 20 patients (13 men, 7 women; mean age, 66.5±10.7 [SD] years; range: 51-88 years) with 20 histopathologically proven pancreatic ACC were reviewed. CT images were analyzed qualitatively and quantitatively and compared to those obtained in 20 patients with PDA. Comparisons were performed using univariate analysis with a conditional logistic regression model. RESULTS: Pancreatic ACC presented as an enhancing (20/20; 100%), oval (15/20; 75%), well-delineated (14/20; 70%) and purely solid (13/20; 65%) pancreatic mass with a mean diameter of 52.6±28.0 (SD) mm (range: 24-120mm) in association with visible lymph nodes (14/20; 70%). At univariate analysis, well-defined margins (Odds ratio [OR], 7.00; P=0.005), nondilated bile ducts (OR, 9.00; P=0.007), visible lymph nodes (OR, 4.33; P=0.028) and adjacent organ involvement (OR, 5.67; P=0.02) were the most discriminating CT features to differentiate pancreatic ACC from PDA. When present, lymph nodes were larger in patients with pancreatic ACC (14±4.8 [SD]; range: 7-25mm) than in those with PDA (8.8±4.1 [SD]; range: 5-15mm) (P=0.039). CONCLUSION: On CT, pancreatic ACC presents as an enhancing, predominantly oval and purely solid pancreatic mass that most frequently present with no bile duct dilatation, no visible lymph nodes, no adjacent organ involvement and larger visible lymph nodes compared to PDA.

MR imaging features of pancreatic acinar cell carcinoma.

PURPOSE: This study aimed to report the magnetic resonance imaging (MRI) features of acinar cell carcinoma (ACC) of the pancreas including diffusion-weighted MRI findings. MATERIALS AND METHODS: The MRI examinations of five patients (3 men, 2 women; median age, 61years) with histopathologically proven ACC of the pancreas were retrospectively reviewed. MR images were analyzed qualitatively (location, shape, homogeneity, signal intensity, vascular involvement and extrapancreatic extent of ACC) and quantitatively (tumor size, apparent diffusion coefficient [ADC] and normalized ADC of ACC). RESULTS: All ACC were visible on MRI, presenting as an oval pancreatic mass (5/5; 100%), with moderate and heterogeneous enhancement (5/5; 100%), with a median transverse diameter of 43mm (Q1, 35; Q3, 82mm; range: 30-91mm). Tumor capsule was visible in 4/5 ACC (80%) and Wirsung duct enlargement in 2/5 ACC (40%). On diffusion-weighted MRI, all ACC (5/5; 100%) were hyperintense on the 3 b value images. Median ADC value of ACC was 1.061×10-3mm2/s (Q1, 0.870×10-3mm2/s; Q3, 1.138×10-3mm2/s; range: 0.834-1.195×10-3mm2/s). Median normalized ADC ratio of ACC was 1.127 (Q1, 1.071; Q3, 1.237; range: 1.054-1.244). CONCLUSIONS: On MRI, ACC of the pancreas presents as a large, oval pancreatic mass with moderate and heterogeneous enhancement after intravenous administration of a gadolinium chelate, with restricted diffusion and a median ADC value of 1.061×10-3mm2/s on diffusion-weighted MRI. Further studies however are needed to confirm our findings obtained in a limited number of patients.

[Value of CT lymphangiography in the detection of lymphatic leakage: a report of nine cases]. / Apport du lymphoscanner pour le diagnostic de fuites lymphatiques : à propos de neuf cas.

PURPOSE: To demonstrate the value of CT lymphangiography to detect lymphatic leakage, especially at the thoracic level, prior to therapeutic intervention. PATIENTS AND METHODS: Between 2004 and 2008, nine patients underwent lymphangiography, followed by CT for the evaluation of intractable lymphatic leakage in spite of optimal medical management. Patients included seven females and two males, with age ranging between 25 and 58 years. Lymphangiography was performed after unilateral or bilateral foot injection(s) of Lipiodol ultrafluid followed by standard radiographs of the chest and abdomen and CT of the chest, abdomen and pelvis. The images were reviewed by two experienced radiologists. RESULTS: Lipiodol leakage was observed in six patients, while three patients showed evidence of lymphangiectasia of the abdominal and/or thoracic lymphatics. Spontaneous resolution of leakage after lymphangiography occurred in three cases. CONCLUSION: CT lymphangiography allows direct evaluation of lymphatics, from pelvis to chest, in order to detect the site of leakage at the origin of a chylous effusion and assist in its management.

Hepatofugal portal flow in advanced liver cirrhosis with spontaneous portosystemic shunts: effects on parenchymal hepatic enhancement at dual-phase helical CT.

BACKGROUND: We investigated whether spontaneous hepatofugal portal flow in advanced cirrhosis affects hepatic enhancement on dual-phase helical computed tomography. METHODS: Fifteen patients with hepatofugal portal flow on Doppler sonography and angiography (group 1) and 15 age- and sex-matched patients with hepatopetal portal flow (control; group 2) underwent dual-phase helical computed tomography. Vascular and liver attenuation values were measured on unenhanced scans and scans obtained during hepatic arterial (HAP; 25 s) and portal venous (PVP; 70 s) phases. RESULTS: Portal vein enhancement was lower during PVP in group 1 than in group 2 ( p < 0.0001). Liver enhancement was higher during HAP and lower and delayed during PVP in group 1 versus group 2 ( p < 0.0001). CONCLUSION: In hepatofugal portal flow, liver enhancement is increased during HAP and compensating for decreased and delayed liver enhancement during PVP, resulting in potential decreased hypervascular tumor conspicuity.

Hepatic and vascular enhancement at dual-phase helical CT: comparison of Iobitridol 300 and Iohexol 300 in a prospective randomized study.

The purpose of this study was to determine hepatic and vascular enhancement, clinical tolerance, and iconographic quality of Iobitridol (300 mg/ml) at dual-phase helical CT and to compare it with Iohexol (300 mg/ml). One hundred forty-six patients were randomly divided into two groups. Each group received 120 ml of Iohexol (group A) or Iobitridol (group B). Mean enhancement of liver, aorta and portal vein was obtained at the arterial phase and at the portal-venous phase. Overall image quality was assessed by two independent blinded investigators. Adverse reactions were recorded. There were no significant differences in demographic characteristics and distribution of patient intrinsic parameters between the two groups, except for blood pressure but without statistical correlation between the difference in blood pressure and the impact on enhancement measurements. There was no significant difference in clinical tolerance and image quality. Mean liver as well as aortic and portal vein enhancement measurements did not show any significant difference. Iobitridol compares favorably with Iohexol. Both products have similar safety, tolerance, and efficacy. Both contrast media have equivalent blood pool concentration and interstitial compartment diffusion.

[Value of high frequency (20mhZ) and doppler ultrasound in the diagnosis of pigmented cutaneous tumors]. / Apport de l'échographie haute fréquence (20 MHz) et du doppler dans le diagnostic des tumeurs cutanées pigmentées.

PURPOSE: Diagnosis of pigmented skin tumors is often difficult. The aim of the present study is to evaluate high frequency ultrasound and Doppler ultrasound in the localization and the characterization of these tumors. MATERIAL AND METHODS: One hundred and seventy six pigmented skin tumors including melanocytic and non melanocytic, benign and malignant lesions have been examined before resection using high frequency ultrasound (20MHz probe) and Doppler ultrasound (13MHz probe-Doppler frequency: 7MHz). Imaging data have been correlated with histological data, available in all cases. RESULTS: Tumors seen at ultrasound were hypoechoic lesions, some of which, particularly malignant melanocytic tumors were vascularized. Precise ultrasonographic location of the tumor was correlated to its histological location: epidermis for purely epidermal proliferations (seborrheic keratoses), superficial dermis for dermal proliferations originating from epidermis (benign dermal nevi, melanomas during vertical growth phase, basal cell carcinomas), middle and deep dermis for dermal proliferations originating from dermis (fibrous histiocytomas, angiomas). CONCLUSION: Ultrasound may help in assessing positive and differential diagnosis of pigmented skin tumors as it precises, before histological examination, the exact location of the lesion within the different skin layers and its origin. As far as malignant melanocytic tumors are concerned, high frequency ultrasound and Doppler ultrasound appear promising in diagnosis algorithm and pronosic of these lesions.

[Imaging of adrenal incidentalomas]. / Imagerie des incidentalomes surrénaliens.

Imaging plays an important role in evaluating fortuitously discovered adrenal masses. These unanticipated masses (incidentalomas) are usually discovered at CT examinations. Although most incidentally discovered adrenal tumors are non-hyperfunctioning adenomas, they must be distinguished from primary or secondary malignant lesions. Recent studies have established that both unenhanced CT scans and chemical shift MR imaging can accurately differentiate benign adenomas from nonadenomatous masses by features that reflect the large amount of lipid found in most adenomas and absent in most nonadenomas. We review here the current imaging issues concerning adrenal incidentalomas including diagnostic approaches and management.

[Value of high-frequency (20 MHz)in the diagnosis of cutaneous tumors]. / Apport de l'échographie haute fréquence (20 MHz) dans l'exploration des tumeurs cutanées.

The purpose of the present study is to asses the value of high frequency ultrasonography (20 MHz), a new noninvasive imaging technique, in cutaneous tumors. Cutaneous tumors are clinically varied and their diagnosis is still based on histopathological analysis. 140 cutaneous tumors have been examined with US and imaging findings have been compared to the results of clinical and histological examinations. This study shows that high frequency ultrasonography, even though it cannot replace pathological analysis, may help the dermatologist in the positive diagnosis of some cutaneous tumors and in accessing the location and the in depth-extension of the lesions in the different layers of the skin.