Comparison of MRI perfusion imaging and single photon emission computed tomography in chronic stroke

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Direct comparisons between MR perfusion-weighted imaging (PWI) and established techniques like SPECT are limited, especially in chronic stroke.
• Understanding perfusion abnormalities is crucial for assessing functional deficits and guiding treatment in stroke recovery.

Purpose of the Study:

• To compare hypoperfusion volumes derived from MR PWI (rCBF, rCBV, rMTT) with SPECT measurements in chronic stroke patients.
• To correlate PWI findings with infarct size (T2-WI) and clinical outcomes.
• To evaluate the potential of PWI in assessing functional impairment and guiding interventional strategies.

Main Methods:

• Seventeen chronic hemispheric infarction patients (mean 90 days post-stroke) underwent MR PWI and (99)Tc-HMPAO SPECT.
• Hypoperfusion volumes were quantified from PWI maps (rCBF, rCBV, rMTT) and compared to SPECT.
• Infarct size was assessed using T2-weighted imaging (T2-WI), and clinical scales were used for functional assessment.

Main Results:

• Significant correlations were observed between lesion location and volume across all PWI hemodynamic parameters (rCBF, rCBV, rMTT) and clinical status, SPECT, and T2-WI findings.
• In three patients, PWI detected hypoperfused areas extending beyond the visible infarct on structural imaging.
• PWI successfully delineated regions of abnormal perfusion that corresponded with functional impairment and structural damage.

Conclusions:

• MR PWI is a valuable tool for delineating perfusion abnormalities in chronic stroke, reflecting the extent of functional impairment and structural damage.
• The detection of peri-infarct hypoperfusion suggests PWI's potential as a non-invasive method to evaluate the effectiveness of interventions aimed at promoting functional recovery.