Seung-Koo Lee MD, PhD, Presenter: Nothing to Disclose

Eun Soo Kim, Abstract Co-Author: Nothing to Disclose

High field strength MRI and high molar gadolinium (Gd) contrast are known to be effective in accurate detection of brain metastasis. The purpose of this study was to compare the diagnostic efficacy of 0.5M Gd enhanced MRI at 3T and 1.0M Gd enhanced MRI at 1.5T.

We restrospectively analyzed 18 consecutive patients (11 males, 7 females; mean age 55) with brain metastasis who received gamma knife surgery (GKS). The first scan was performed on 3T MRI after injection of 0.2mmol/kg 0.5M Gd contrast, gadopentetate dimeglumine (Gd-DTPA). Second MRI was localization MRI for GKS on 1.5T MRI after injection of 0.2mmol/kg 1.0M Gd contrast, gadobutrol. Post-contrast 3D T1 gradient echo images were obtained with same geometry on 1.5T and 3T scanner. Regions of interests (ROIs) were settled at measurable 42 metastatic lesions and contralateral normal white matter. Lesion brain contrast to noise ratio (CNR) was measured and paired t-test analysis was performed between Gd-DTPA at 3T and gadobutrol at 1.5T.

The measurable 42 lesions showed significantly higher lesion-brain CNR on gadobutrol at 1.5T than Gd-DTPA at 3T (p < 0.0001). Total number of enhancing lesions on Gd-DTPA 3T was 106 while gadobutrol at 1.5T detected 27 additional lesions. Mean CNR was higher on gadobutrol at 1.5T (2.17±0.60 vs. 1.77±0.51, p=0.0001, paired t-test, two-tailed).

Raising Gd concentration is more effective in detection of brain metastasis than raising field strength of MR scanner because of various factors other than higher field strength.

These characteristics of field strength and Gd concentration difference might improve the achievable contrast to noise ratio and better results in detection of metastatic lesion.

Lee, S, Kim, E, Increasing Detection Rate of Brain Metastasis: Raising Field Strength vs Gadolinium Concentration.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034475.html