Color Duplex evaluation of the mesenteric artery().

Ischemic colitis is the most common form of intestinal ischemia. Diagnosis is made at clinical examination and endoscopy and completed by vascular imaging, but color Doppler US may become a first-line imaging technique for the evaluation of the mesenteric circulation.We present the case of an 80-year-old woman hospitalized for recurrent ischemic colitis of the sigmoid. At a previous hospitalization, color Doppler US examination showed medium to severe stenosis at the origin of the inferior mesenteric artery. However, CT angiography was negative and the condition was therefore misdiagnosed. Eight months later the patient was admitted again with abdominal pain and rectal hemorrhage. Rectosigmoidoscopy documented the presence of ischemia of the sigmoid mucosa. Angiography showed the presence of severe stenosis at the origin of the inferior mesenteric artery so revascularization was carried out by percutaneous transluminal angioplasty (PTA) during the same session. Follow-up showed normal patency of the inferior mesenteric artery after revascularization, and subsequent endoscopic evaluation documented gradual colonic mucosal ischemia resolution. Blood flow at the level of the inferior mesenteric artery was assessed using color Doppler US. The presented case confirms that color Doppler US is a valid first-line imaging technique in the assessment of ischemic intestinal lesions. It is reliable in the evaluation of the mesenteric arterial circulation, and it also allows assessment of blood flow alterations caused by stenosis and identification of localized hemodynamic stenosis which may be missed at CT-angiography or MR-angiography. Arteriography remains the examination of choice in case of discrepancy between first-and second-line imaging techniques and in all cases which offer the possibility of endovascular revascularization.

Pseudoaneurysm of the common hepatic artery: treatment with a stent-graft.

We report a case of a pseudoaneurysm of the common hepatic artery treated with a stent-graft in a 67-year-old man. The patient presented with severe catheter bleeding through a drain following surgical and interventional procedures performed for therapeutic management of a choledochal cholangiocarcinoma. Selective hepatic arteriography showed a pseudoaneurysm close to the origin of the gastroduodenal artery. After a preliminary attempt at arterial embolization, it was decided to use a stent-graft to bridge the false aneurysm. Complete pseudoaneurysm exclusion was seen after the procedure with preservation of hepatic arterial flow.

Effects of lipiodol retention on MRI signal intensity from hepatocellular carcinoma and surrounding liver treated by chemoembolization.

Opinion is divided regarding the influence of iodized oil on MRI signal intensity of hepatic tumours treated with transcatheter arterial chemoembolization (TACE), in which lipiodol deposits. The aim of our study was to ascertain whether or not lipiodol directly influences the MRI signal intensity of hepatocellular carcinoma (HCC) treated by TACE and that of the surrounding liver. Thirteen patients with HCC were studied retrospectively. CT and MRI scans were performed both before and 3 months after TACE. The CT scan was performed to check whether embolized nodules contained lipiodol and how lipiodol was distributed within them. In addition, eight patients were examined prospectively within 7 days after TACE. In these patients a CT scan was performed to see how lipiodol was distributed in the neoplastic nodules and in normal hepatic parenchyma. In the first group of patients the contrast-to-noise (C/N) ratio on T1-weighted (T1W) images and the T2 relaxation time on T2-weighted (T2W) images were calculated for both neoplasm and surrounding liver. In the second group of patients we also measured the signal intensity of non-neoplastic liver that was either permeated or not permeated by lipiodol. The data were analysed with Wilcoxon's test. On T1W images we observed that the retention of lipiodol increased the C/N ratio in all the tumours studied within 1 week after TACE. In the patients studied 3 months after TACE the C/N ratio was not significantly increased. On T2W images lipiodol retention did not change tumour signal intensity. The iodized oil did not change the signal intensity of the liver surrounding the tumour, in comparison with the liver not permeated by lipiodol, on either T1W or T2W images. The results indicate that lipiodol does not modify the signal intensity in non-neoplastic hepatic parenchyma in which it is deposited; after 3 months it does not significantly affect the signal of the tumours that accumulated it. Lipiodol produces a high signal on T1W images over the first few days following TACE in those tumours in which it is deposited.

[Liver metastasis from carcinoid: diagnostic imaging]. / Metastasi epatiche da carcinoide: semeiotica per immagini.

Our study was aimed at describing the diagnostic imaging patterns of carcinoid liver metastases. Six patients with liver metastases secondary to carcinoid tumor were examined. The metastases were histologically proved in each patient. All patients were examined with ultrasonography (US), Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Digital Subtraction Angiography (DSA). All patients were treated with transcatheter embolization of liver metastases. Diagnostic imaging methods showed ten to many dozen metastases in each patient. Tumor size ranged 0.5 to 14 cm. US showed hypoechoic, hyperechoic and isoechoic carcinoid liver metastases with a hypoechoic halo. Large lesions had anechoic central areas due to colliquative necrosis. Hypoechoic patterns were the most frequent ones. Precontrast CT showed hypodense metastases; very small lesions were isodense relative to surrounding liver. CT during contrast agent injection showed that the metastases were hyperdense in the arterial phase; contrast enhancement was poorer in the portal phase. Large lesions showed a hypodense central area due to necrosis which remained hypodense in the late phase. The metastases were hypointense on T1-weighted and hyperintense on T2-weighted MR images. Gradient echo dynamic imaging with Gd-DTPA showed high-signal metastases in the arterial phase and lower signal intensity in the portal phase. DSA, an essential exam before embolization, showed tortuous and elongated intra- and extrahepatic arteries and tumor neovascularization with no malignant abnormalities. In the capillary phase, tumor uptake and inhomogeneous hypervascular patterns were shown. Portal veins were only displaced and compressed, but never infiltrated by the metastases. All the techniques we used contributed to assess liver involvement by carcinoid metastases. DSA must be used only before treatment; both CT and MRI showed the hypervascular patterns of the metastases, but no technique could predict their nature.