Delayed Enhancement of Subendocardial Infarcted Myocardium with Gadobenate Dimeglumine: A Paradoxical Effect—Is a Double Dose Too Much?

Myocardial delayed enhancement using a single dose (0.1 mmol/kg) of gadobenate dimeglumine: contrast resolution versus intraventricular blood and viable myocardium

PURPOSE

This study was done to estimate delayed enhancement (DE) contrast resolution of infarcted myocardium (IM) relative to intraventricular blood (IB) and viable myocardium (VM) using gadobenate dimeglumine (Gd-BOPTA).

MATERIALS AND METHODS

After approval from the Ethics Committee, we retrospectively evaluated 21 consecutive patients (61+/-10 years) with a healed myocardial infarction who underwent 1.5-T magnetic resonance (MR) imaging using an inversion-recovery-prepared turbo gradient-echo sequence 10 minutes after injection of 0.1 mmol/kg of Gd-BOPTA. Signal intensity (SI) was measured in arbitrary units (au) for IM, IB, VM, and outside the patient. Contrast-to-noise ratio (CNR) was calculated for IM to IB and IM to VM. Seven consecutive patients (59+/-6 years) with a healed myocardial infarction studied with similar technique but with 0.1 mmol/kg of gadoterate meglumine (Gd-DOTA) served as the control group. The Mann-Whitney U test was used to compare groups.

RESULTS

Mean SI of IM was 44+/-16 au for Gd-BOPTA and 20+/-6 au for Gd-DOTA (p<0.001), that of IB 35+/-15 au and 14+/-5 au (p=0.016), and that of VM 7+/-3 au and 5+/-2 au (p=0.116), respectively. Mean IM to IB CNR was 10+/-7 for Gd-BOPTA and 8+/-5 for Gd-DOTA (p=0.836), that of IM to VM was 45+/-27 and 18+/-6, respectively (p=0.012).

CONCLUSIONS

Gd-BOPTA at 0.1 mmol/kg produced a higher myocardial DE and an IM to VM CNR than a single dose of Gd-DOTA. No significant difference was observed for IM to IB CNR.

Left ventricular infarct size assessed with 0.1 mmol/kg of gadobenate dimeglumine correlates with that assessed with 0.2 mmol/kg of gadopentetate dimeglumine

OBJECTIVE

To determine myocardial infarct (MI) size during cardiovascular magnetic resonance at 1.5 Tesla using 0.1 mmol/kg body weight of gadobenate dimeglumine (Gd-BOPTA) and 0.2 mmol/kg body weight of gadopentetate dimeglumine (Gd-DTPA).

METHODS

Twenty participants (16 men, 4 women), aged 58 +/- 12 years, with a prior chronic MI were imaged in a crossover design. Participants received 0.2 mmol/kg body weight of Gd-DTPA and 0.1 mmol/kg body weight of Gd-BOPTA on 2 occasions separated by 3 to 7 days.

RESULTS

The correlations were high between Gd-DTPA and Gd-BOPTA measures of infarct volume (r = 0.93) and the percentage of infarct relative to left ventricular myocardial volume (r = 0.85). The size and location of the infarcts were similar (P = 0.9) for the 2 contrast agents. Interobserver correlation of infarct volume (r = 0.91) was high.

CONCLUSIONS

In chronic MI, late gadolinium enhancement identified with a single 0.1 mmol/kg body weight dose of Gd-BOPTA is associated in volume and location to a double (0.2 mmol/kg body weight) dose of Gd-DTPA. Lower doses of higher relaxivity contrast agents should be considered for determining left ventricular myocardial infarct size.

Gadobenate dimeglumine as a contrast agent for dynamic breast magnetic resonance imaging: effect of higher initial enhancement thresholds on diagnostic performance

RATIONALE AND OBJECTIVE

Gadobenate dimeglumine (Gd-BOPTA), a high-relaxivity contrast agent, has been recently proposed for dynamic MR imaging of the breast. The objective of this study was to optimize the diagnostic performance of Gd-BOPTA-enhanced dynamic breast MR imaging by using adjusted initial enhancement thresholds.

METHODS

Thirty-four patients with 36 breast lesions (malignant/benign = 28/8) underwent dynamic breast MRI with 0.1 mmol/kg Gd-BOPTA and 120-second time resolution. A score system based on shape (round/oval/lobular = 0; linear/dendritic/stellate = 1), margins (defined = 0; undefined = 1), pattern (homogeneous = 0; inhomogeneous = 1; rim = 2), kinetics (continuous = 0; plateau = 1; washout = 2), and initial enhancement was used. Initial enhancement was determined with standard (<50% = 0; 50%-100% = 1; >100% = 2) and adjusted (<100% = 0; 100%-240% = 1; >240% = 2) thresholds. Scores of 0 to 3 indicated benign lesions and scores of 4 to 8 malignant lesions. Diagnostic performance was assessed in terms of sensitivity, specificity, positive and negative predictive values, and overall accuracy.

RESULTS

The initial enhancement was >100% for 26 malignant and 7 benign lesions and >240% for 16 and 1 lesions, respectively. The overall score was 5.89 +/- 1.34 with standard thresholds and 5.50 +/- 1.53 with adjusted thresholds (P = 0.003) for cancers, 4.00 +/- 1.93 and 3.25 +/- 1.75 (P = 0.028) for benign lesions, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 96%, 13%, 79%, 50%, and 78%, respectively, with standard thresholds and 96%, 75%, 93%, 86%, and 92%, respectively, with adjusted thresholds. A ductal carcinoma in situ was false negative whereas a fat necrosis and a papilloma were false positive with both thresholds. Three fibroadenomas, 1 adenosis, and 1 fibrosis were false positive with standard thresholds but true negatives with adjusted thresholds.

CONCLUSIONS

Lesion characterization with Gd-BOPTA requires higher thresholds for initial enhancement than those used with conventional Gd-chelates, leading to improved specificity, predictive values, and accuracy.