Using intraoperative dynamic contrast-enhanced T1-weighted MRI to identify residual tumor in glioblastoma surgery

Abstract

Object The goal of surgery in high-grade gliomas is to maximize the resection of contrast-enhancing tumor without causing additional neurological deficits. Intraoperative MRI improves surgical results. However, when using contrast material intraoperatively, it may be difficult to differentiate between surgically induced enhancement and residual tumor. The purpose of this study was to assess the usefulness of intraoperative dynamic contrast-enhanced T1-weighted MRI to guide this differential diagnosis and test it against tissue histopathology. Methods Preoperative and intraoperative dynamic contrast-enhanced MRI was performed in 21 patients with histopathologically confirmed WHO Grade IV gliomas using intraoperative 3-T MRI. Standardized regions of interest (ROIs) were placed manually at 2 separate contrast-enhancing areas at the resection border for each patient. Time-intensity curves (TICs) were generated for each ROI. All ROIs were biopsied and the TIC types were compared with histopathological results. Pharmacokinetic modeling was performed in the last 10 patients to confirm nonparametric TIC analysis findings. Results Of the 42 manually selected ROIs in 21 patients, 25 (59.5%) contained solid tumor tissue and 17 (40.5%) retained the brain parenchymal architecture but contained infiltrating tumor cells. Time-intensity curves generated from residual contrast-enhancing tumor and their preoperative counterparts were comparable and showed a quick and persistently increasing slope (“climbing type”). All 17 TICs obtained from regions that did not contain solid tumor tissue were undulating and low in amplitude, compared with those obtained from residual tumors (“low-amplitude type”). Pharmacokinetic findings using the transfer constant, extravascular extracellular volume fraction, rate constant, and initial area under the curve parameters were significantly different for the tumor mass, nontumoral regions, and surgically induced contrast-enhancing areas. Conclusions Intraoperative dynamic contrast-enhanced MRI provides quick, reproducible, high-quality, and simply interpreted dynamic MR images in the intraoperative setting and can aid in differentiating surgically induced enhancement from residual tumor.

Accuracy of High-Field Intraoperative MRI in the Detectability of Residual Tumor in Glioma Grade IV Resections

“…However, leakage of contrast agent and enhancement of reactive tissue might be misleading in T1 imaging with contrast enhancement [21]. More advanced techniques like T1-weighted dynamic contrast-enhanced MRI or 3D-spectroscopic imaging were recently applied to identify residual tumor in glioblastoma surgery under assistance of intraoperative MRI [27].…”

“…Showing equal sensitivity ioMRI appears more specific in primary than in recurrent glioblastoma. cy of ioMRI in the future [27,29]. Dynamic contrast enhancement may provide better differentiation between contrast-enhancing tissue and leakage and DTI may reveal additional information about tumor margins [28].…”

Intraoperative perfusion magnetic resonance imaging: Cutting-edge improvement in neurosurgical procedures

“…It can be applied various times as it is independent of T1-effects after saturation, has proven to be as reliable as preoperatively performed DSC-MRI [8,9] and can distinguish residual tumor form surgically induced artefacts. Dynamic contrast-enhanced T1-weighted perfusion (DCE-MRI) has alternatively been used intraoperatively [10] . The beauty of this approach that requires more time than DSC-MRI (also at 3T) is that there is a by-product with the acquired T1-weighted images as the slope of contrast enhancement can easily be analyzed without the need for additional software.…”

“…Thus, DCE-MRI measures contrast agent concentration as a function of time. Very recently, DCE-MRI was used intraoperatively at a 3 T MR scanner [10] . The used setup took 3 min and 45 s for the perfusion sequence.…”

Brain tumor surgery: supplemental intra-operative imaging techniques and future challenges

“…[40,41] In addition, the time for image acquiring and the need of stop the surgery for it, prolong time of surgery and anesthesia. [42][43][44] Roder et al studied retrospectively 117 patients after conventional surgery, after 5-ALA, and after iMRI they found that mean residual tumor volume after iMRI-assisted surgery (0.5 [0.0e4.7] cm 3 ) was significantly smaller compared to the residual tumor volume after 5-ALAguided surgery (1.9 [0.0-13.2] cm 3 ; P = 0.022), which was significantly smaller than in conventional surgery (4.7 [0.0-30.6] cm 3 ; P = 0.007). Total resections were significantly more common in iMRI (74%) than in 5-ALAassisted (46%, P = 0.05) or conventional surgery (13%, P = 0.03).…”