Differential diagnosis of vertebral compression fracture using in-phase/opposed-phase and short TI inversion recovery imaging.

BACKGROUND: Magnetic resonance imaging (MRI) is highly useful for detecting diseases of the bone marrow. The sensitivity for detecting compression fracture is very high, but specificity is low for differential diagnosis between malignant and benign cases. PURPOSE: To evaluate the usefulness of in-phase/opposed-phase and short TI inversion recovery (STIR) magnetic resonance imaging (MRI) of bone marrow for differentiation between benign and malignant vertebral compression fractures. MATERIAL AND METHODS: A retrospective review of 66 patients with 70 vertebral compression fractures was performed. The signal intensity ratio (SIR) defined as SIR (opposed/in) was calculated from in-phase/opposed-phase MR images, and the signal intensity ratio as SIR (STIR) was calculated from STIR MR images. The relationships between values of SIR (opposed/in) and SIR (STIR) and the differential diagnosis of malignant vs. benign fractures were considered. RESULTS: When SIR (opposed/in) was less than 1.0, bone marrow was benign. The bone marrow was malignant when both SIR (opposed/in) was greater than 1.0 and SIR (STIR) was less than 2.0. CONCLUSION: In cases of acute compression fracture, malignant bone marrow showed SIR(STIR) values less than 2.0 and SIR (in/opposed) greater than 1.0. In contrast, benign bone marrow showed SIR (STIR) values greater than 2.5. For chronic compression fracture, malignant bone marrow showed SIR (in/opposed) greater than 1.0. Bone marrow was benign in all cases with SIR (in/opposed) less than 1.0.

Use of dynamic phase subtraction (DPS) map in dynamic contrast-enhanced MRI of the breast.

BACKGROUND: The Breast Imaging Reporting and Data System (BI-RADS) of the American College of Radiology recommends careful examination of the region of interest (ROI) in areas that seem to show a washout pattern on time-intensity curve (TIC). However, it is difficult to identify malignancies because many benign lesions also show enhancement, and these include cysts, hemorrhage, fibrosis, and necrosis in the mass. PURPOSE: This study was performed to assess the performance of the dynamic phase subtraction (DPS) map for dynamic contrast-enhanced magnetic resonance imaging (MRI) of the breast. A DPS map is a map image with pixel-by-pixel subtraction of an early-phase image from a delayed-phase image obtained in a dynamic study. MATERIALS AND METHODS: The use of the DPS map was analyzed retrospectively in 53 patients (32-84 years old) who underwent dynamic contrast-enhanced MRI of the breast. Sensitivity and specificity were compared with and without a DPS map for masses diagnosed as malignant lesions by biopsy. In addition, the patterns of time-intensity curves 30 seconds, 90 seconds, and 5 minutes after injection of contrast agent were compared with and without a DPS map. RESULTS: Sensitivity increased from 0.78 to 0.95, and specificity increased from 0.71 to 0.95 with reference to the DPS map. The pattern of TIC changed from continuous to a plateau in 9 cases, from a plateau to washout in 21 cases, and from continuous to washout in 7 cases. CONCLUSION: Use of the DPS map of dynamic contrast-enhanced MRI of the breast results in high detection rates of malignant masses, allows accurate ROI setting of TIC, and reduces operator's task.

Differentiation of hepatic tumors by use of image contrast with T2-weighted MRI.

Differentiation of hepatic tumors is often evaluated in terms of qualitative diagnostic performance. The signal intensity patterns of hepatic masses are known to differ on certain T2-weighted imaging sequences. In this study, we investigated the quantitative analysis of hepatic masses by using an index called the "T2-shine ratio." Fast-spin-echo (FSE), half-Fourier acquisition single-shot turbo spin echo (HASTE), and true-FISP sequences obtained with quick-imaging techniques during a single breath-hold were examined in 74 patients. T2-shine ratios were calculated by use of the signals of regions of interest (ROIs) placed on a tumor and peripheral tissue: the T2-shine ratio is defined as (tumor signal-liver signal)/liver signal. The rate of change in the T2-shine ratio was compared among three sequences of FSE, HASTE, and true-FISP. The T2-shine ratio of FSE deducted from HASTE was significantly higher for hepatic cysts than for other masses. The T2-shine ratio of HASTE deducted from True-FISP was less than zero for hemangioma. For the value that deducted the T2-shine ratio of HASTE from the T2-shine ratio of true-FISP, hemangiomas had a significantly lower value than did cysts and metastases (P < 0.05), but there was no significant difference from hepatocellular carcinomas (HCCs). Although liver cysts, cavernous hemangiomas, and other lesions could be differentiated, it was virtually impossible to distinguish HCCs from metastatic tumors. In conclusion, the quantitative analysis of hepatic tumors was able to differentiate among these lesions by use of the T2-shine ratio.