Time-delayed contrast-enhanced MRI improves detection of brain metastases and apparent treatment volumes

Abstract

B rain metastases (BMs) are the most common intracranial tumors in adults, occurring in 20%-40% of cancer patients. 26 Their incidence has been increasing due to both prolonged systemic control and improved detection, making BMs a growing cause of mortality and morbidity.14,31 Magnetic resonance imaging is currently the standard of care for the diagnosis of BMs because its sensitivity is superior to CT,22,32 and refinements in MRI techniques allow the modality to detect metastases that are not seen with routine image-acquisition protocols. The abbreviatioNs BM = brain metastasis; GRE = gradient echo; SRS = stereotactic radiosurgery. obJective Contrast-enhanced MRI is the preeminent diagnostic test for brain metastasis (BM). Detection of BMs for stereotactic radiosurgery (SRS) planning may improve with a time delay following administration of a high-relaxivity agent for 1.5-T and 3-T imaging systems. Metastasis detection with time-delayed MRI was evaluated in this study. methods Fifty-three volumetric MRI studies from 38 patients undergoing SRS for BMs were evaluated. All studies used 0.1-mmol/kg gadobenate dimeglumine (MultiHance; Bracco Diagnostics) immediately after injection, followed by 2 more axial T1-weighted sequences after 5-minute intervals (final image acquisition commenced 15 minutes after contrast injection). Two studies were motion limited and excluded. Two hundred eighty-seven BMs were identified. The studies were randomized and examined separately by 3 radiologists, who were blinded to the temporal sequence. Each radiologist recorded the number of BMs detected per scan. A Wilcoxon signed-rank test compared BM numbers between scans. One radiologist determined the scan on which BMs were best defined. All confirmed, visible tumors were contoured using iPlan RT treatment planning software on each of the 3 MRI data sets. A linear mixed model was used to analyze volume changes. results The interclass correlations for Scans 1, 2, and 3 were 0.7392, 0.7951, and 0.7290, respectively, demonstrating excellent interrater reliability. At least 1 new lesion was detected in the second scan as compared with the first in 35.3% of subjects (95% CI 22.4%-49.9%). The increase in BM numbers between Scans 1 and 2 ranged from 1 to 10. At least 1 new lesion was detected in the third scan as compared with the second in 21.6% of subjects (95% CI 11.3%-35.3%). The increase in BM numbers between Scans 2 and 3 ranged from 1 to 9. Between Scans 1 and 3, additional tumors were seen on 43.1% of scans (increase ranged from 1 to 14). The median increase in tumor number for all comparisons was 1. There was a significant increase in number of BMs detected from Scan 1 to Scan 2 (p < 0.0367) and from Scan 1 to Scan 3 (p < 0.0264). In 34 of the 51 subjects (66.7%), the radiologist selected the third scan as the one providing the clearest tumor definition. There was an average 25.4% increase in BM volume between Scans 1 and 2 (p < 0.0001) and a 9% increase in BM volume between Scans 2 and 3 (p = 0.0001). coNclusioNs In patients who are ...

Time-Dependent Changes in the Magnetic Resonance Detection of Brain Metastases Using Single-Dose Gadobutrol

“…To date, the available studies have used linear structured Gd-DTPA and there are no studies that have used circular structured gadobutrol. Consistent with the earlier studies that have reported detection of lesions less than 5 mm (5,18), this study also reports detection of an additional six lesions in the 7-and 10-min delay groups compared with the 3-min group. All the additionally detected lesions had diameters of less than 5 mm.…”

“…The diagnosis was mainly based on typical imaging manifestations and clinical follow-up. Second, unlike other studies (5,18), the delay time was up to 10 minutes, and this was mainly because well-known Chinese hospitals do not allow for longer examination time due to excess clinical work. Finally, the small sample size of this study does not allow for generalization of the findings.…”

“…In another study, three MRI scans (5, 10, and 15 minutes) after administration of the contrast medium detected at least one new lesion in every subsequent scan. The volume of the lesions significantly increased from scan 1 to scan 2 and from scan 2 to scan 3 (18). Increased mass of the tumor and edema were the reasons for easy diagnosis of large lesions.…”

“…However, the optimal delay time is not yet clear (5,15,18) ence in detection was observed for lesions larger than 10 mm in size (5). In another study, three MRI scans (5, 10, and 15 minutes) after administration of the contrast medium detected at least one new lesion in every subsequent scan.…”

Brain metastases: neuroimaging

“…For instance, a time delay of 15 minutes after contrast injection results in at least one additional lesion being detected in 43% of patients (Kushnirsky et al, 2016). Resultant radiation tumor treatment volumes also increase with time delay.…”