No abstract

A phase III multicenter study was conducted in 89 patients with known intracranial vascular lesions to evaluate an extracellular gadolinium contrast agent, gadoteridol, for intracranial magnetic resonance (MR) angiography. The pre- and postcontrast MR angiograms of 82 patients were evaluated by the unblinded investigators and by two blinded readers (A and B) for visualization of lesions; arterial and venous anatomy; extent, size, and number of lesions; and disease classification. The unblinded readers indicated that lesions were visualized better on postcontrast images in the following categories: venous anatomy, 87 (81%) of 107 lesions; arterial anatomy, 43 lesions (40%); and extent or size of lesions, 38 lesions (36%). In 29 (35%) of 82 patients, the unblinded readers determined that enhanced MR angiography provided more diagnostic information than unenhanced MR angiography. The blinded readers determined that enhanced MR angiography provided more information for visualization of vascular anatomy in more than 60% of cases. The additional information provided with gadoteridol would have changed the diagnosis in nine (8%) of 107 lesions seen by the unblinded readers, 11 (12%) of 90 lesions seen by reader A, and three (3%) of 93 lesions seen by reader B. The results confirm that the use of gadoteridol improves the visualization of intracranial vascular lesions with MR angiography. The authors conclude that development of new postprocessing algorithms will improve the utility of contrast-enhanced MR angiography.

Gadodiamide injection is a nonionic, low-osmolar formulation of a paramagnetic metal chelate complex consisting of gadodiamide and caldiamide sodium. The efficacy of gadodiamide injection as a magnetic resonance (MR) imaging enhancement medium was evaluated by imaging intracranial 9L-glioma lesions induced in rats and naturally occurring lesions in dogs. T1- and T2-weighted spin-echo images were obtained before and after administration of gadodiamide injection at doses of 0.1 and 0.2 mmol/kg. On the precontrast T1-weighted images, the intracranial lesions were not well seen, appearing isointense to normal brain parenchyma. Although the presence of disease was shown unequivocally on the T2-weighted images, the margins of the masses could not be delineated. Postcontrast T1-weighted images were characterized by marked enhancement of the tumor, with no change in signal intensity in the surrounding edematous brain tissue. Gadodiamide injection was efficacious in identifying areas of blood-brain barrier breakdown associated with intracranial masses.

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