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FUNKCIONALNI TRANSKRANIJSKI DOPPLER I TEHNECIJ-99M-HMPAO JEDNOFOTONSKA EMISIJSKA KOMPJUTERIZIRANA TOMOGRAFIJA U PROCJENI NEUROVASKULARNOG SPARIVANJA

INTRODUCTION: Functional Transcranial Doppler (fTCD) is a practical method with high temporal resolution for assessment of blood flow velocity (BFV) changes coupled to brain activity and in patients with impaired vasoreactivity. Technetium-99m-hexamethypropylenamine oxime single photon emission computed tomography (99mTc-HMPAO-SPECT) provides reliable information about regional cerebral blood flow (rCBF) distribution during activation studies and pathological blood flow patterns in patients with carotid stenosis and vertebrobasilar insufficiency. We investigated the validity of fTCD with 99mTc-HMPAO-SPECT in evaluation of neurovascular coupling (NC) during brain activation task. MATERIALS AND METHODS: Ten healthy right-handed volunteers (6 women and 4 men ; average&plusmn ; ; SD age, 28, 1&plusmn ; ; 5, 34 years) underwent fTCD and SPECT testing during computer game, which contained visuospatial and visumotor elements. Relative BFV changes were measured simultaneously in both middle cerebral arteries (MCAs) during baseline and activation task. We calculated the percentage increase in BFV (BFVI%) compared with baseline. Measurement of rCBF in parietal regions was performed by regions of interest (ROI) analysis. The percentage increase in cerebral perfusion was calculated as percentage changes of baseline values. RESULTS: Playing game induced mean BFVI% in left and right MCAs (average&plusmn ; ; SD) ; 7, 74&plusmn ; ; 2, 47% and 10, 79&plusmn ; ; 2, 46%, respectively). Relative perfusion increases in right parietal region were (average&plusmn ; ; SD ; 0, 956&plusmn ; ; 0, 016 versus 0, 985&plusmn ; ; 0, 019 count/second, rest versus stimulation, respectively) in all patients. The percentage increase in cerebral perfusion during activation in right parietal region versus left parietal region was (average&plusmn ; ; SD ; 4, 584&plusmn ; ; 2, 041% versus 3, 474&plusmn ; ; 2, 310%). CONCLUSION: 99mTc-HMPAO-SPECT and fTCD might detect measurement of rCBF and BFV changes during activation task. Functional TCD showed moderate BFVI% in both MCAs. 99mTc-HMPAO-SPECT showed slight rCBF percentage increase in parietal lobes, reflecting the neuronal activity level. Both techniques might be helpful in evaluation of neurovascular coupling and used in neurological patients following stroke. Neuroactivation studies are gaining more importance in a routine clinical management of stroke leading to better understanding of the process of cerebral plasticity.

TCD; SPECT

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