VIENNA -- F-18 FDG-PET/CT can identify metabolic abnormalities beyond what structural imaging can detect in subacute and chronic stroke patients, according to findings presented March 7 at ECR.
In a study involving 24 patients with confirmed subacute or chronic stroke, F-18 FDG-PET/CT was positive in a majority of cases and demonstrated more extensive metabolic abnormalities than CT and MRI, noted presenter Dr. Raquel Perez-Lopez, PhD, of the Vall d´Hebron Institute of Oncology in Barcelona.
"F-18 FDG-PET/CT has emerged as a valuable complementary modality in the assessment of subacute and chronic stroke,” she told attendees.
CT and MRI remain the gold standard of care for stroke assessment. In the subacute and chronic phases of stroke -- days to months after the initial event -- metabolic changes in brain tissue may persist or evolve in ways that conventional imaging does not reflect, Perez-Lopez explained. F-18 FDG-PET/CT, which can detect hypometabolism, or reduced cellular energy, has shown promise in detecting such changes, but its role alongside standard neuroimaging has not been well characterized, she noted.
To bridge the gap, Perez-Lopez and colleagues retrospectively analyzed 24 patients with confirmed subacute or chronic stroke who underwent brain F-18 FDG-PET/CT at their center. Patients had also undergone CT, perfusion MRI, and CT angiography of the supra-aortic trunks. The team collected clinical and demographic data -- including cardiovascular risk factors, neurological deficits, and the interval from stroke diagnosis to PET/CT -- and calculated concordance between the techniques using correlation coefficients.
The cohort included 14 men and 10 women with a mean age of 64.9. Cardiovascular risk factors were present in 70.8% of patients, and 83.3% had documented neurological deficits.
According to the results, FDG-PET/CT was positive in 83.3% of cases, with hypometabolism most commonly identified in right cortical regions. The right middle cerebral artery was the most frequent culprit vessel, involved in 33.3% of cases, followed by the right internal carotid artery in 25% of cases. Significant carotid stenosis was detected in 45.8% of patients, more often in those with cardiovascular risk factors, Perez-Lopez reported.
In addition, concordance between PET/CT and structural imaging was moderate at best: correlation coefficients were 0.53 with MRI and 0.25 with both CT and CTA. In 37.5% of cases, PET/CT demonstrated more extensive metabolic abnormalities than either CT or MRI alone. Among patients imaged more than 180 days after stroke onset, 75% showed discordant findings between PET/CT results and clinical-radiological correlation.
“Unlike conventional structural imaging alone, PET/CT uniquely reveals functional and metabolic alterations that remain unclear on CT or MRI,” Perez-Lopez said.
Ultimately, the data is preliminary, and larger prospective studies will be needed to further define the clinical role of FDG PET/CT in poststroke evaluation. Integrating the technique into multidisciplinary stroke protocols is another key step, Perez-Lopez noted.
"Multidisciplinary collaboration between radiology, nuclear medicine, and neurology is essential to ensure comprehensive patient evaluation -- integrating structural, functional, and clinical perspectives for optimal outcomes in stroke care,” she concluded.
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