Biao Huang MD, Presenter: Nothing to Disclose

Changhong Liang MD, Abstract Co-Author: Nothing to Disclose

Hongjun Liu MD, Abstract Co-Author: Nothing to Disclose

Guangyi Wang MD, Abstract Co-Author: Nothing to Disclose

Shui Xing Zhang MD, Abstract Co-Author: Nothing to Disclose

Gadobenate dimeglumine (Gd-BOPTA has a substantially higher T1 relaxivity in blood due to its capacity for weak, transient interaction with serum proteins. One major advantage of 3.0-T imaging is improvement of signal-to-noise ratio (SNR) compared with 1.5-T imaging. The increased SNR leads to a higher contrast-to-noise ratio (CNR) between enhancing and non-enhancing tissues. We hypothesized that use of a low dose of Gd-BOPTA could achieve a comparable or greater level of contrast enhancement of brain metastases at 3.0-T compared with level of contrast enhancement obtained using conventional contrast agent at 1.5-T.  

A total of 18 patients with known brain metastases were first imaged at 1.5-T with 0.1 mmol/kg Gd-DTPA. Patients returned for imaging at 3.0-T with gadobenate dimeglumine (Gd-BOPTA) at least 24 hours later with cumulative doses of 0.025 mmol/kg, 0.05 mmol/kg, 0.075 mmol/kg, and 0.1 mmol/kg (0.1 mmol/kg body weight overall) Gd-BOPTA. All images were reviewed independently by two neuroradiologists to analyze the number and conspicuity of the lesions. The contrast-to-noise ratio between enhancing lesions and normal contralateral white matter was calculated. For 3.0-T with with different cumulative doses of Gd-BOPTA, CNR of lesions was intraindividually compared with contrast-to-noise ratio at 1.5-T with 0.1 mmol/kg Gd-DTPA by using the Wilcoxon matched-pairs signed rank test.

At 1.5-T with 0.1 mmol/kg Gd-DTPA, mean contrast-to-noise ratio between enhanced lesions and cerebral white matter was 12.0±2.5. With 3.0-T imaging with different cumulative doses of Gd-BOPTA, mean contrast-to-noise ratios were 7.2±4.1, 15.3±6.3, 25.4±11.0, and 31.9±13.2. At 3.0-T with 0.05 mmol/kg Gd-BOPTA, CNR was 1.34-fold higher than that at 1.5-T with 0.1 mmol/kg Gd-DTPA (P<0.01)

When compared with the conventional gadolinium agent Gd-DTPA and a 1.5-T MR imaging system, our data suggest that assessment of possible brain metastases is comparable with 0.05 mmol/kg Gd-BOPTA and a 3.0-T MR imaging system. However, a dose of 0.1 mmol/kg at 3.0-T improved lesion detection, delineation and conspicuity; this led to greater confidence among our readers for detection or exclusion of metastatic lesions.

A 0.05 mmol/kg dose of Gd-BOPTA used with a 3.0-T MRI system is sufficient for detection of brain metastases.

Huang, B, Liang, C, Liu, H, Wang, G, Zhang, S, Low-dose Contrast-enhanced MRI of Brain Metastases at 3.0 T Using High-Relaxivity Contrast Agents.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8000099.html