Naobumi Yashiro

Diffusion-weighted Half-fourier Single-shot Turbo Spin Echo Imaging in Breast Tumors: Differentiation of Invasive Ductal Carcinoma from Fibroadenoma

Purpose The purpose of this investigation is to evaluate the usefulness of diffusion-weighted half-Fourier single-shot turbo spin echo (DW-HASTE) imaging in differentiating invasive ductal carcinoma from fibroadenoma. Method The DW-HASTE imaging was performed in patients with invasive ductal carcinoma (n = 16) and fibroadenoma (n = 6). Images were obtained with diffusion-sensitizing gradients of 0 and 700 mm2/s. The apparent diffusion coefficient (ADC) was calculated. Results The DW–HASTE imaging was not affected with susceptibility and chemical shift artifacts usually present in DW echo planar imaging. The DW-HASTE imaging had low tumor detectability (62%), however. The difference in mean ADC of invasive ductal carcinoma (1.216 ± 0.189 × 10−3mm2/s) and fibroadenoma (1.495 ± 0.181 × 10−3mm2/s) was statistically significant. Conclusion Apparent diffusion coefficient measurement using DW-HASTE imaging is helpful in differentiating invasive ductal carcinoma from fibroadenoma. Nevertheless, DW-HASTE imaging has low detectability at present; therefore, more technologic improvement is desired.

Fat necrosis of breast:A potential pitfall in breast MRI

Fat necrosis is a benign nonsuppurative inflammatory process of adipose tissue. Occasionally fat necrosis may mimic a breast cancer clinically, mammographically, and sonographically. There have been some previous reports on the MR imaging of the fat necrosis. In some MR findings of fat necrosis, it was difficult to distinguish it from malignant lesions. We report a case of fat necrosis presenting the irregular enhancement with the non-enhancing area of central areas on MRI.

CT and MR imaging of fatty tumors of the liver.

The presence of fat in hepatic masses narrows the range of differential diagnoses down to hepatic angiomyolipoma, lipoma, adenoma, hepatoma, metastatic fatty tumors of the liver, focal fatty infiltration of the liver, and extrahepatic fatty masses such as intraperitoneal implants from malignant teratomas, and packed omentum. We report six hepatic tumors containing fat (lipoma, hepatocellular carcinoma, and calcified mass with fat–fluid level) with CT and magnetic resonance (MR) imaging. The distribution of fat was diffuse in the lipomas and some hepatocellular carcinomas and localized in other hepatocellular carcinomas and fat-fluid masses. The density ranged from – 100 to 0 HU. High intensity areas on both T1− and T2-weighted MR images corresponded to the hypodense areas on CT.

MR Imaging of hepatocellular carcinoma

Forty-two patients with hepatocellular carcinoma (HCC) were examined by magnetic resonance (MR) imaging. The presence of tumor was suggested in 41 of 42 cases by a high-intensity area on T2 weighted spin-echo (SE) images with a repetition time (TR) of 1.6 s. Specific findings of HCC such as the presence of a capsule, mosaic pattern, and tumor thrombus in major veins were noted in 10, two, and seven cases, respectively. In six cases the tumor pattern changed from a well-defined mass to an irregular, ill-defined one according to pulse sequence (SE: echo time 35 and 70 ms; TR 1.6 and 0.4 s). In our early experience MR was almost equal to conventional X-ray CT in the detection of main or daughter lesions and in the determination of extent and characterization of HCC.

MR imaging of hepatoma treated by embolization

The magnetic resonance findings of two hepatomas treated by embolization are presented. The T2-weighted spin echo images showed an increase in signal intensity in the tumor after embolization. This phenomenon corresponded to a decrease in tumor density on CT and to necrosis observed histologically. Magnetic resonance also demonstrated gas bubbles as low signal foci within the embolized tumor.

Portosystemic collaterals on MR imaging

Fourteen patients with various portosystemic collaterals (seven esophageal varices, three paraumbilical veins, two splenorenal shunts, and two mesenteric varices) were imaged with magnetic resonance (MR) imaging using a superconducting imager. Collateral pathways were demonstrated as tortuous structures of no or low signal intensity on spin-echo image, and flow related enhancement did not cause any difficulty in evaluation. Direct sagittal images are especially useful for paraumbilical vein and coronal images for esophageal and mesenteric varix. The clinical role of MR in the assessment of portosystemic collaterals is discussed also in comparison with CT and ultrasound.

Lobar Intensity Differences of the Liver on Mr Imaging

Differences in signal intensity involving lobes of the liver were noted in seven cases of liver tumor. The clinical significance and possible cause of these differences in lobar intensity are discussed.

MR imaging of portal vein thrombus in hepatocellular carcinoma.

This report describes the magnetic resonance (MR) demonstration of portal vein tumor thrombus (PVTT) in hepatocellular carcinoma (HCC). In two cases of HCC with PVTT diagnosed by angiography, MR demonstrated PVTT as areas of increased MR signal in the portal vein. Our limited experience suggests the potential utility of MR imaging for diagnosis of PVTT.

Inflammatory intramammary lymph node mimicking the malignant lesion in dynamic MRI:A case report

Enlarged intramammary lymph node (LN) may be caused by inflammation [Arch. Surg. 109 (1974) 759.], reaction to dermatitis [Radiology 137 (1980) 15.], tuberculosis [Histopathology 17 (1990) 91.], foreign body such as gold [Hum. Pathol. 19 (1988) 992.], neoplasm including metastasis [Arch. Surg. 109 (1974) 759; AJR, Am J Roentgenol 146 (1986) 133.], and malignant lymphoma [AJR, Am J Roentgenol 161 (1993) 779.]. It is difficult to distinguish benign enlarged LNs from malignant lesion clinically, mammographically, and sonographically. There have been a few reports on the magnetic resonance imaging (MRI) of enlarged intramammary LNs in the English literature. In this article, we present a case in which dynamic MRI indicated inflammatory LNs as highly suspicious of malignancy.

Small bowel obstruction due to pickled Japanese apricot: CT findings.

A 32-year-old-man with mental retardation and renal dysfunction presented to our hospital with a 2 day duration of abdominal pain and vomiting. His temperature was 37.1°C. He had no history of previous abdominal surgery. Physical examination of the abdomen revealed slight tenderness and decreased bowel sound. Laboratory findings on admission suggested acute inflammation with slight elevation of white blood cells (15,200/ l) and C-reactive protein (1.03 mg/dl) accompanied by renal failure with slight elevation of blood urea nitrogen (28 mg/dl) and serum creatinine (1.5 mg/dl) levels. Abdominal radiographs showed dilated loops of the small intestine with air-fluid levels. No obvious free air or abnormal calcification was detected. CT examination of the abdomen and pelvis with intravenous contrast material showed distended small intestine without wall thickenings (Fig. 1). A well defined, round, concentric low/high/low density mass was revealed in the fluid-filled distal ileum at the predicted site of obstruction. Abrupt transition to normal-looking intestine was noted distal to the mass. No obvious ascites was seen. Small bowel obstruction due to foreign body was concluded. The patient underwent an emergency laparotomy. A round, movable, hard mass was palpable within the ileum 1–2 cm proximal to the ileocecal valve. Ileum distal to the mass was normal. The foreign body was a pickled ume, a Japanese apricot. The patient recovered uneventfully and was discharged 1 month later.