Dynamic spin-echo imaging with Gd-DTPA: value in the differentiation of hepatic tumors.

Thirty patients with hemangiomas (n = 6), benign liver cell tumors (n = 7), and primary or metastatic malignant tumors of the liver (n = 17) underwent dynamic MR imaging with Gd-DTPA to determine the value of the procedure in the differentiation of hepatic tumors. The diagnoses were proved by histology or follow-up. Hemangiomas had a significantly greater mean T2 value (192.1 +/- 34.8 msec) than did both benign liver cell tumors (71.9 +/- 16.9 msec; p less than .01) and primary or metastatic malignant tumors (79.7 +/- 21.2 msec; p less than .01), but the T2 values of benign liver cell tumors and malignant tumors were not significantly different. Both hemangiomas and benign liver cell tumors had a significantly greater mean signal-intensity ratio (1.86 +/- 0.60 and 1.77 +/- 0.26, respectively) than did malignant tumors (1.04 +/- 0.34; p less than .01) in the early phase after Gd-DTPA administration, and hemangiomas had a significantly greater signal-intensity ratio (1.59 +/- 0.21) than did both benign liver cell tumors (1.21 +/- 0.08; p less than .01) and malignant tumors (1.06 +/- 0.26; p less than .01) in the delayed phase. These results suggest that dynamic MR images obtained after administration of Gd-DTPA are useful in differentiating hepatic hemangiomas, benign liver cell tumors, and malignant liver lesions

High metabolic activity in the visual cortex of early blind human subjects.

Glucose metabolism has been studied in the visual cortex of early blind human subjects. In the forebrain of these subjects, regional glucose utilization was the highest in the striate and prestriate cortical areas. Furthermore, this activity was higher than in blindfolded sighted subjects, whether at rest or during an auditory or tactile task. These observations raise the question of the functionality of the blind's visual cortex