Follow-Up MRI for Small Brain AVMs Treated by Radiosurgery: Is Gadolinium Really Necessary?

OBJECTIVEArteriovenous malformations (AVMs) present no pathologic tissue, and radiation dose is confined in a clear targeted volume. The authors retrospectively evaluated the role of the biologically effective dose (BED) after Gamma Knife radiosurgery (GKRS) for brain AVMs.METHODSA total of 149 consecutive cases of unruptured AVMs treated by upfront GKRS in Lille University Hospital, France, were included. The mean length of follow-up was 52.9 months (median 48, range 12–154 months). The primary outcome was obliteration, and the secondary outcome was complication appearance. The marginal dose was 24 Gy in a vast majority of cases (n = 115, 77.2%; range 18–25 Gy). The mean BED was 220.1 Gy2.47 (median 229.9, range 106.7–246.8 Gy2.47). The mean beam-on time was 32.3 minutes (median 30.8, range 9–138.7 minutes). In the present series, the mean radiation dose rate was 2.259 Gy/min (median 2.176, range 1.313–3.665 Gy/min). The Virginia score was 0 in 29 (19.5%), 1 in 61 (40.9%), 2 in 41 (27.5%), 3 in 18 (12.1%), and 4 in 0 (0%) patients, respectively. The mean Pollock-Flickinger score was 1.11 (median 1.52, range 0.4–2.9). Univariate (for obliteration and complication appearance) and multivariate (for obliteration only) analyses were performed.RESULTSA total of 104 AVMs (69.8%) were obliterated at the last follow-up. The strongest predictor for obliteration was BED (p = 0.03). A radiosurgical obliteration score is proposed, derived from a fitted multivariable model: (0.018 × BED) + (1.58 × V12) + (−0.013689 × beam-on time) + (0.021 × age) − 4.38. The area under the receiver operating characteristic curve was 0.7438; after internal validation using bootstrap methods, it was 0.7088. No statistically significant relationship between radiation dose rate and obliteration was found (p = 0.29). Twenty-eight (18.8%) patients developed complications after GKRS; 20 (13.4%) of these patients had transient adverse radiological effects (perilesional edema developed). Predictors for complication appearance were higher prescription isodose volume (p = 0.005) and 12-Gy isodose line volume (V12; p = 0.001), higher Pollock-Flickinger (p = 0.02) and Virginia scores (p = 0.003), and lower beam-on time (p = 0.03).CONCLUSIONSThe BED was the strongest predictor of obliteration of unruptured AVMs after upfront GKRS. A radiosurgical score comprising the BED is proposed. The V12 appears as a predictor for both efficacy and toxicity. Beam-on time was illustrated as statistically significant for both obliteration and complication appearance. The radiation dose rate did not influence obliteration in the current analysis. The exact BED threshold remains to be established by further studies.

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“…Our group has also developed, over time, special sequences to further evaluate AVM obliteration by MRI, particularly for smallsized ones. 26…”

Section: Follow-upmentioning

confidence: 99%

Biologically effective dose and prediction of obliteration of unruptured arteriovenous malformations treated by upfront Gamma Knife radiosurgery: a series of 149 consecutive cases

Tuleasca

Peciu-Florianu²,

Leroy³

et al. 2021

Journal of Neurosurgery

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“…49 Previous studies have demonstrated the utility of ASL in the evaluation of cerebral AVMs after treatment. [50][51][52][53][54] Leclerc et al compared the detectability of residual AVMs after SRS between non-contrast MRI consisting of TOF-MRA plus ASL and contrast-enhanced MRI including contrast-enhanced dynamic MRA plus post-contrast thin-slice 3D T1-weighted image (T1WI). 53 The noncontrast enhancement method was superior to the contrastenhanced methods for the detection of residual AVMs.…”

Section: Asl For Pediatric Neuroimagingmentioning

confidence: 99%

“…[50][51][52][53][54] Leclerc et al compared the detectability of residual AVMs after SRS between non-contrast MRI consisting of TOF-MRA plus ASL and contrast-enhanced MRI including contrast-enhanced dynamic MRA plus post-contrast thin-slice 3D T1-weighted image (T1WI). 53 The noncontrast enhancement method was superior to the contrastenhanced methods for the detection of residual AVMs. Heit et al compared the detection rate of residual AVMs between DSA and ASL and found that ASL was highly sensitive and specific in the detection of residual cerebral AVMs following SRS treatment.…”

Section: Asl For Pediatric Neuroimagingmentioning

confidence: 99%

Arterial Spin Labeling for Pediatric Central Nervous System Diseases: Techniques and Clinical Applications

Kitajima

Uetani

2023

MRMS

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Dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) are techniques used to evaluate brain perfusion using MRI. DSC requires dynamic image acquisition with a rapid administration of gadolinium-based contrast agent. In contrast, ASL obtains brain perfusion information using magnetically labeled blood water as an endogenous tracer. For the evaluation of brain perfusion in pediatric neurological diseases, ASL has a significant advantage compared to DSC, CT, and single-photon emission CT/positron emission tomography because of the lack of radiation exposure and contrast agent administration. However, in ASL, optimization of several parameters, including the type of labeling, image acquisition, background suppression, and postlabeling delay, is required, because they have a significant effect on the quantification of cerebral blood flow (CBF).In this article, we first review recent technical developments of ASL and age-dependent physiological characteristics in pediatric brain perfusion. We then review the clinical implementation of ASL in pediatric neurological diseases, including vascular diseases, brain tumors, acute encephalopathy with biphasic seizure and late reduced diffusion (AESD), and migraine. In moyamoya disease, ASL can be used for brain perfusion and vessel assessment in pre-and post-treatment. In arteriovenous malformations, ASL is sensitive to detect small degrees of shunt. Furthermore, in vascular diseases, the implementation of ASLbased time-resolved MR angiography is described. In neoplasms, ASL-derived CBF has a high diagnostic accuracy for differentiation between low-and high-grade pediatric brain tumors. In AESD and migraine, ASL may allow for accurate early diagnosis and provide pathophysiological information.

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“…Several MRI sequences, such as dynamic arterial spin-labeling MR angiography (MRA) and time-resolved contrast-enhanced MRA, have been reported to be useful for confirming AVM obliteration. 9,[22][23][24] It is true that such MRI sequences can detect microscopic remnants of AVMs, but they cannot quantify the progress of AVM obliteration or the therapeutic effect of SRS on AVM hemodynamics. Time-averaged 3D flow MRI is a quantitative MRI method using phase contrast (PC) techniques and allows for the noninvasive measurement of flow parameters, such as mean blood flow in vessels.…”

mentioning

confidence: 99%

Hemodynamic changes during the obliteration process for cerebral arteriovenous malformations after radiosurgery

Takeda¹,

Hasegawa²,

Kin³

et al. 2022

Neurosurgical Focus

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OBJECTIVE The process of cerebral arteriovenous malformation (AVM) obliteration following radiosurgery is poorly understood. Authors of this retrospective study aimed to assess the changes in AVM hemodynamics after stereotactic radiosurgery (SRS) by using 3D flow magnetic resonance imaging (MRI) to elucidate the process of AVM obliteration. METHODS Twenty-four patients with AVMs treated with SRS between July 2015 and December 2017 were included in this study and classified into two groups depending on the duration of AVM obliteration: group A, obliteration within 3 years (n = 15); and group B, obliteration taking more than 3 years or no obliteration (n = 9). Blood flow (ml/min) in the largest feeding artery was measured before and after SRS by using time-averaged 3D flow MRI. The decreasing rate of blood flow in the feeding artery after SRS was calculated as the percent change from baseline blood flow. A Wilcoxon rank-sum test was used to compare the decreasing blood flow rate between the two groups at 4 and 12 months after SRS. RESULTS For the entire cohort, the mean decrease in blood flow in the feeding artery from baseline was 29% at 4 months and 71% at 12 months after SRS. In general, blood flow after SRS decreased faster in group A and slower in group B. The decreasing rates in blood flow at 4 and 12 months after SRS were significantly different between the two groups (p = 0.02 and < 0.001, respectively). CONCLUSIONS Tracking changes in AVM hemodynamics after SRS may be useful for assessing the progress of AVM obliteration and the therapeutic effects of SRS, possibly contributing to the prediction of subsequent obliteration outcome.

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Follow-Up MRI for Small Brain AVMs Treated by Radiosurgery: Is Gadolinium Really Necessary?

Cited by 12 publications

References 23 publications

Biologically effective dose and prediction of obliteration of unruptured arteriovenous malformations treated by upfront Gamma Knife radiosurgery: a series of 149 consecutive cases

Biologically effective dose and prediction of obliteration of unruptured arteriovenous malformations treated by upfront Gamma Knife radiosurgery: a series of 149 consecutive cases

Arterial Spin Labeling for Pediatric Central Nervous System Diseases: Techniques and Clinical Applications

Hemodynamic changes during the obliteration process for cerebral arteriovenous malformations after radiosurgery

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