In Vitro imaging of MRI and Ultrasound for Colorectal Carcinoma

PURPOSE: To evaluate and compare the accuracy of magnetic resonance imaging (MRI) and ultrasound (US) for detection and estimation of invasion depth of colorectal carcinoma (CRC) by correlation with histopathologic findings in vitro, and to find out the best MR pulse sequence for accurate delineation of tumor from surrounding normal tissue. MATERIALS AND METHODS: Resected specimens of CRC from 45 patients were examined about tumor detectability and invasion depth of US using high frequency (5-17 MHz) linear transducer in a tube filled with normal saline and MRI in a 8-channel quadrate head coil. The institutional review board approved this study and informed consent was waived. MRI with seven pulse sequences of in- and out-of-phases gradient echo T1 weighted images, fast spin echo T2 weighted image and its fat suppression image, fast imaging employing steady-state acquisition (FIESTA) and its fat suppression image, and diffusion weighted image (DWI) were performed. In each case, both imaging findings of MRI and US were evaluated independently for detection and estimation of invasion depth of tumor by consensus of two radiologists and were compared about diagnostic accuracy according to the histopathologic findings as reference standard. Seven MR pulse sequences were evaluated on the point of accurate delineation of tumor from surrounding normal tissue in each specimen. RESULTS: In specimens of CRC, both imaging modalities of MRI (91.1%) and US (86.7%) showed relatively high diagnostic accuracy to detect tumor and evaluate invasion depth of tumor. In early CRC, diagnostic accuracy of US was 87.5% and that of MRI was 75.0%. There was no statistically significant difference between two imaging modalities (p > 0.05). The best pulse sequence among seven MR sequences for accurate delineation of tumor from surrounding normal tissue in each specimen of CRC was fast spin echo T2 weighted image. CONCLUSION: MRI and US show relatively high diagnostic accuracy to detect tumor and evaluate invasion depth of resected specimen of CRC. The most excellent pulse sequence of MRI for accurate delineation of tumor from surrounding normal tissue in CRC is fast spin echo T2 weighted image.

A Case Report of Mediastinal Leiomyosarcoma / 결핵

The leiomyosarcoma is uncommom tumor that consists of 10% of all sarcoma incidence and commonly arise from retroperitomeum or mesentery. But leiomyosarcoma arose from mediastinum is very rare and only incidental case report is present. Mediastial leiomyosarcoma may originate from superior vene cava, pulmonary artery, small vessels of alveoli, esophagus and cardiac muscle. Common symptoms that are related with leimoyosarcoma of mediastinum are cough and dydpnea but dysphagia, chest pain and hemoptysis can be produced. Although long term survival after complete resection of tumor was reported in localized disease, there wes no effective therapy that prolong the survival in patients who had disseminated disease of huge tumor mass. We report the case of posterior mediastinal leiomyosarcoma confirmed by aspiration cytology and immunohistochemical staining, along with a review of literature.