Effects of Susceptibility Artifacts on Perfusion MRI in Patients with Primary Brain Tumor: A Comparison of Arterial Spin-Labeling versus DSC

Abstract

Background and purpose: Our aim was to investigate the effects of intratumoral hemorrhage, calcification, and postoperative changes on the sensitivity of arterial spin-labeling and DSC perfusion MR imaging in patients with primary brain tumors.

Materials and methods: Eighty-six brain tumor lesions were examined with single-phase and multiphase arterial spin-labeling and DSC perfusion MR imaging. The lesions that had no intratumoral bleeding/calcifications and history of surgery were assigned to group 1 (n = 38), and the lesions that had these were assigned to group 2 (n = 48). The relative regional cerebral blood flow was calculated in both perfusion methods, and relative regional cerebral blood volume was calculated in DSC. Imaging results were correlated with histopathology or follow-up.

Results: In the quantitative evaluation, the sensitivity and specificity of relative regional cerebral blood flow in multiphase arterial spin-labeling perfusion were 94.4% and 80% in group 1 and 78.3% and 88% in group 2, respectively. The sensitivity and specificity of relative regional cerebral blood flow in DSC perfusion were 88.9% and 75% in group 1 and 78.3% and 84% in group 2, respectively. The sensitivity and specificity of relative regional cerebral blood volume in DSC perfusion were 66.7% and 100% in group 1 and 69.6% and 96% in group 2, respectively. In the qualitative evaluation, the sensitivities for single-phase and multiphase arterial spin-labeling were 48.2% and 79.3%, respectively, with 100% specificity for both.

Conclusions: The sensitivity and specificity of multiphase arterial spin-labeling were similar to those of DSC perfusion irrespective of bleeding and calcification in primary brain tumors. Thus, we suggest that noncontrast multiphase arterial spin-labeling can be used instead of DSC perfusion MR imaging in the diagnosis and follow-up of intracranial tumors.

FIG 1.

ROIs were located in the tumor and white matter of the contralateral hemisphere, and the measurements are seen on mpASL (A) and DSC (B) perfusion maps.

FIG 2.

Anaplastic astrocytoma in a 44-year-old female patient. There is a mass in the T2-weighted (B) sequence showing a signal increase in the right thalamus. Also, there is a slight expansion in both T2-weighted (B) and the postcontrast T1-weighted (A) sequences. There is no significant enhancement in the postcontrast T1-weighted (A) MR image. There are no significant increases in perfusion in the mass localization derived from the DSC (C) perfusion color map (DSC rrCBF = 1.1). In the mpASL perfusion map (D), the perfusion increase in the mass localization can be seen clearly (ASL rrCBF = 3.3) (arrow).

FIG 3.

A 49-year-old male patient who underwent an operation and received chemoradiotherapy due to a glioblastoma in the temporoparietal region 1 year ago. T1-weighted (A) and T2-weighted (C) MR images show postoperative changes and alterations in the signal intensities in the right temporoparietal region. The postcontrast image (B) shows wide-scale enhancement in the site of the operation. The T2*-weighted image (D) shows hypointensities secondary to old bleeding residues (black arrow). The DSC perfusion map (E) shows a large perfusion signal loss caused by leakage artifacts in the contrasted areas (DSC rrCBF = 1.3). In the mpASL perfusion map (F), there is a significant increase in perfusion at the site of the operation (white arrows) (ASL rrCBF = 3.5). The patient was diagnosed with a recurrent glioblastoma after the second operation.

FIG 4.

The ROC analysis curve. The blue line shows mpASL perfusion, and the green and the brown lines represent the DSC perfusion MR imaging technique for rrCBF and rrCBV, respectively.

FIG 5.

Anaplastic astrocytoma in a 41-year-old male patient. Postcontrast T1-weighted (A) image shows a wide nonenhancing mass lesion in the right temporoparietal region. There was no diffusion restriction (not shown here). The DSC (B) and mpASL (C) maps show significantly hyperperfused areas within the mass (arrows) (DSC rrCBF = 2.3, ASL rrCBF = 4.6). The spASL (D) map shows no increases in perfusion. It is also remarkable that the signal-to-noise ratio of spASL is lower than that of mpASL.