Takeshi Ichimura

Congenital Arteriovenous Malformation of the Pancreas : Its Diagnostic Features on Images

To analyze diagnostic features on images of congenital arteriovenous malformation (AVM) of the pancreas, we analyzed the diagnostic findings in six patients with the disease, using gray-scale ultrasonography (US), color Doppler US, computed tomography, and angiography and analyzed previously reported cases. AVM characteristic findings on images were multiple, small hypoechoic nodules on US, mosaic appearance of the lesion and pulsatile wave form in the portal vein on color Doppler US, conglomerated small nodular enhancement of the lesion and early appearance of the portal vein on CT, and a racemose network and early appearance of the portal vein on angiography. Five of the six patients underwent surgery, and all resected specimens were histologically found to be AVMs of the pancreas; however, one with developed portal hypertension at surgery died of repeated bleeding from esophageal varices. From analysis of total of 35 cases including our six cases, a mosaic appearance of the lesion was found in 100% and a pulsatile wave form in the portal vein in 77.8% on color Doppler US. Color Doppler US is noninvasive and useful for detecting congenital AVM of the pancreas at an early stage, preventing the portal hypertension causing esophageal varices and their rupture.

Efficacy of SPIO-MR imaging in the diagnosis of liver metastases from colorectal carcinomas.

Aim: To determine whether superparamagnetic iron oxide-enhanced magnetic resonance imaging (SPIO-MRI) could replace intravenous contrast-enhanced spiral CT (iv-CT) and spiral CT during arterial portography (CTAP) combined with spiral CT hepatic angiography (CTHA) in the diagnosis of liver metastases from colorectal carcinomas. Methods: Twenty-six adult patients with liver metastases were studied preoperatively by means of iv-CT, CTAP/CTHA, and SPIO-MRI. Preoperative diagnoses using iv-CT, CTAP/CTHA, and SPIO-MRI were compared with intraoperative and pathological findings in resected specimens. The gold standard for the lesions that were resected was histological examination. Intraoperative findings represented the gold standard for lesions that were not resected. Results: Twenty-six patients were found to have a total number of 43 liver metastases. The sensitivities of iv-CT, CTAP/CTHA, and SPIO-MRI were 74.4, 100, and 90.7%, respectively. SPIO-MRI was significantly superior to iv-CT (p < 0.05). The positive predictive values of iv-CT, CTAP/CTHA, and SPIO-MRI were 97.0, 91.5, and 100%, respectively. CTAP/CTHA yielded four false-positive lesions. In contrast, we detected no false-positive findings using SPIO-MRI. Conclusions: These results suggest that SPIO-MRI might not completely replace CTAP/CTHA, but could replace iv-CT in the diagnosis of liver metastases from colorectal carcinomas. It is thought that SPIO-MRI is a promising imaging modality for diagnosing liver metastases in patients with colorectal carcinoma because of its relatively high sensitivity and extremely high specificity.

Renal Artery Aneurysm: Evaluation with Color Doppler Ultrasonography Before and After Percutaneous Transarterial Embolization

Renal artery aneurysms account for 22% of all visceral aneurysms.1 The prevalence of renal artery aneurysms in the general population is reported to vary between 0.01% and 1.0%2; however, this prevalence has recently increased because of the greater detection of these aneurysms made possible by advances in ultrasonography, CT, and MR imaging. The most serious complication of renal artery aneurysms is their rupture, which is followed by sudden death.3 The likelihood of rupture seems to increase as the diameter of the aneurysm exceeds 1 cm.2,3 Although surgical treatment had been common for these aneurysms (i.e., total renal resection), a percutaneous embolization technique has also recently been performed with success.4 This technique is less invasive than surgical resection for patients with renal artery aneurysms and sometimes preserves renal function. We report a case of a renal artery aneurysm 4 cm in diameter treated with percutaneous transcatheter embolization whose therapeutic effect was better evaluated by color Doppler ultrasonography than CT and MR imaging.

Pancreas: imaging diagnosis with color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography

Recent advances of ultrasound imaging have made possible to depict various diseases and conditions of the pancreas. Color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography are feasible to show vascular abnormalities, differentiate the solid and cystic tumors, decide tumor extent, and help to perform interventional treatments of the pancreatic diseases. Those techniques will contribute to the more precise and easier diagnosis and to prompt decision of the treatments of the pancreatic disorders. Radiologists should recognize the diagnostic feasibility and limitations of those techniques in order to avoid unnecessary examinations on the patients, and obtain precise diagnostic images.

The diagnostic value of TAT value for early detection of thrombosed false lumen in acute aortic dissection

ConclusionOur results shows molecular markers, particularly TAT, is useful for early detection of thrombus formation in the false lumen in acute aortic dissection.