Cerebrovascular Reactivity Mapping in Brain Tumors Based on a Breath-Hold Task Using Arterial Spin Labeling.

Area of Science:

• Neuroimaging
• Radiology
• Oncology

Background:

• Hemodynamic measurements like cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) are crucial for diagnosing and characterizing brain tumors.
• Previous research demonstrated the potential of arterial spin labeling (ASL) combined with vasoactive stimulation for non-invasive CBF and CVR evaluation, but this had not been applied to tumors.

Purpose of the Study:

• To investigate the application of pseudo-continuous ASL (PCASL) with breath-holding at 3T for measuring CBF and CVR in high-grade gliomas and metastatic lesions.
• To explore differences in CBF and CVR across tumoral, peritumoral regions, and different tumor types.

Main Methods:

• A pseudo-continuous ASL (PCASL) sequence with breath-holding at 3T was used in 27 brain tumor patients.
• Baseline CBF and CVR were measured in volumes of interest (VOIs) including tumor, edema, gray matter, and peritumoral regions.
• Differences were evaluated between contralateral and ipsilateral gray matter and peritumoral regions, as well as across VOIs and tumor types.

Main Results:

• Tumor CBF was higher in grade 4 gliomas than in metastases.
• In grade 4 gliomas, edema exhibited lower CBF than tumor and contralateral gray matter.
• Cerebrovascular reactivity (CVR) differed between grade 3 and grade 4 gliomas, and between grade 4 gliomas and metastases. A CVR cut-off of 27.9% was suggested to differentiate grade 3 from grade 4 gliomas.

Conclusions:

• ASL-based CBF and CVR mapping provides insights into the perilesional environment, aiding in the detection of infiltrative disease, especially in grade 4 gliomas.
• Cerebrovascular reactivity (CVR) shows promise as a biomarker for distinguishing between grade 3 and grade 4 gliomas.