[Usefulness of dynamic MR mammography for diagnosis of axillary lymph node status in breast cancer patient].

A retrospective study was performed to evaluate whether dynamic MR imaging is useful for the diagnosis of axillary lymph node metastases from breast cancer. Thirty-five patients with breast cancer were scanned and 147 lymph nodes were detected and compared with pathological nodal status. The parameters were the long axis dimension, the short axis dimension, the long-to-short axis (L/S) ratio, the shape, the contrast enhancement ratio (CER), the CER of lymph node-to-primary tumor (L/P) ratio. All parameters had significant differences between metastatic and normal nodes and there was a positive correlation between the CER of primary breast tumors and metastatic nodes. Multivariate analysis identified three parameters: the shape, the CER (1st phase), the L/P ratio (1st phase). ROC analysis revealed the shape and CER are superior in diagnostic performance to L/P ratio. If the shape and CER (1st phase) 60% and above are employed as criteria, the sensitivity, the specificity, the accuracy and the positive and negative predictive value were 86.0%, 78.4%, 81.0%, 67.2% and 91.6%, respectively. This method gives us useful information about the evaluation of axillary lymph node status preoperatively.

Metastases in fatty liver: appearance on conventional spin-echo, fast-spin-echo, and echo-planar T2-weighted MR images.

A 71-year-old woman with liver metastases from colon adenocarcinoma in a severe fatty liver underwent T2-weighted MR imaging with conventional spin-echo (CSE), breath-hold fast-SE (BH-fast-SE), respiratory-triggered fast-SE (RT-fast-SE), and multishot SE echo-planar (SE-EP) techniques. CSE and SE-EP T2-weighted images showed the metastases as areas of high signal intensity. In contrast, RT-fast-SE and BH-fast-SE images showed them as areas of low signal intensity. Metastatic tumors in severe fatty liver can be shown as low signal-intensity areas with T2-weighted MR imaging using fast-SE sequences without use of the fat-suppression technique.

Focal hepatic lesion detection: comparison of four T2-weighted MR imaging pulse sequences.

PURPOSE: To evaluate T2-weighted magnetic resonance (MR) imaging with conventional spin-echo, breath-hold fast spin-echo, respiratory-triggered fast spin-echo, and breath-hold multishot spin-echo echo-planar sequences for detection of focal hepatic lesions. MATERIALS AND METHODS: T2-weighted MR images obtained with the four sequences in 56 patients with 107 solid and 124 nonsolid lesions were retrospectively analyzed. Image review was conducted on a liver segment-by-segment basis; a total of 408 liver segments were reviewed separately and independently for solid and nonsolid lesions by three radiologists. Diagnostic accuracy was evaluated with receiver operating characteristic analysis. RESULTS: Lesion-to-liver contrast-to-noise ratio was highest with multishot echo-planar images of both solid and nonsolid lesions. Diagnostic accuracy for solid lesions was statistically significantly better with conventional spin-echo images than with any other type of image (P < .0001). Diagnostic accuracy for nonsolid lesions was statistically significantly better with respiratory-triggered fast spin-echo images than with any other type of image (P < .0001). Image quality was best with breath-hold fast spin-echo images. CONCLUSION: Conventional spin-echo MR imaging should not be replaced with breath-hold fast spin-echo or multishot spin-echo echo-planar imaging, despite the shorter acquisition times that are possible with the latter two sequences.

Overestimating the size of hepatic malignancy on helical CT during arterial portography: equilibrium phase CT and pathology.

PURPOSE: Overestimating the size of hepatic malignancy with helical CT during arterial portography (CTAP) can be a potential pitfall in determining liver resection area. We evaluated the prevalence and extent of overestimation of hepatic malignancy on CTAP in correlation with helical equilibrium phase CT (EPCT) and pathologic findings. METHOD: CTAP and EPCT in 47 histologically proven malignant hepatic tumors [33 hepatocellular carcinomas (HCCs) and 14 metastases] in 39 patients were retrospectively studied. Nineteen tumors were resected and pathologically evaluated. RESULTS: The size overestimation ratios (CTAP/EPCT) ranged from 1.02 to 1.56 (mean +/- SD 1.24 +/- 0.16) in HCC and from 1.00 to 2.48 (1.34 +/- 0.42) in metastasis. In 19 surgical specimens, the overestimation ratios (CTAP/specimen) ranged from 1.05 to 1.45 (1.20 +/- 0.13) in HCC and from 1.10 to 1.38 (1.22 +/- 0.10) in metastasis. Histopathologically, flattening of parenchymal structures (100%), atrophy of hepatic cords (95%), sinusoidal congestions (95%), fibrosis and ductular proliferation (58%), and no tumor were seen in peritumoral parenchyma corresponding to perilesional perfusion defects with CTAP. CONCLUSION: CTAP frequently and significantly overestimates the size of malignant hepatic tumors. This phenomenon is attributable to either benign histopathological changes in the perilesional liver parenchyma caused by parenchymal compression or portal venous obstruction by malignant liver tumors or to a siphoning effect by hypervascular neoplasms.

Overestimation ratio of hepatic lesion size on spiral CT arterial portography: an indicator of malignancy.

PURPOSE: To assess the reliability of the size-overestimation ratio obtained from spiral CT arterial portography (CTAP) and spiral equilibrium-phase CT (EPCT) in distinguishing malignant focal hepatic lesions from benign ones. METHODS: The CTAP images and EPCT images obtained five minutes after CTAP in 39 patients with focal hepatic lesions were retrospectively analyzed. Fifty-eight lesions (hepatocellular carcinoma [HCC], 33; metastasis, 10; liver cyst, 10; cavernous hemangioma, 2; adenomatous hyperplasia [AH], 2; focal nodular hyperplasia [FNH], 1) had their sizes measured on CTAP and EPCT images using the calipers on the CT console. RESULTS: The size-overestimation ratios (CTAP/EPCT) were 1.24+/-0.15 in HCC, 1.28+/-0.26 in metastasis, 1.02+/-0.23 in liver cyst, 0.98+/-0.34 in cavernous hemangioma, 0.94+/-0.39 in AH, and 1.00 in FNH. Mean size-overestimation ratios for benign- and malignant-lesion groups were 1.00+/-0.37 and 1.25+/-0.18, respectively (p < 0.0001). When a cutoff level was set at 1.05, sensitivity and specificity for malignancy were 91% and 93%, respectively. CONCLUSIONS: In comparison with EPCT, CTAP significantly overestimates the size of malignant hepatic tumors. This phenomenon may be an indicator of hepatic malignancy.