technetium-tc-99m-bicisate and Subarachnoid-Hemorrhage

The aim of this study was to correlate cerebral blood flow (CBF) and mean transient time (MTT) measured on dynamic perfusion computerized tomography (CT) with CBF using (99m)Tc ethyl cysteinate dimer-single-photon emission computerized tomography (SPECT) in patients with cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH).. Thirty-five patients with vasospasm following aneurysmal SAH (12 men and 23 women with a mean age of 49.3 +/- 10.1 years) underwent imaging studies; thus, 35 perfusion CT scans and 35 SPECT images were available for comparison. The CBF and MTT values in 12 different brain regions were defined relative to the interhemispheric occipital cortex values using perfusion CT scans and were compared with qualitative relative (rel)CBF estimated on SPECT images. In brain regions with normal, mild (relCBF 71-85%), moderate (relCBF 50-70%), and severe (relCBF < 50%) hypoperfusion on SPECT, the mean relCBF values measured on perfusion CT were 1.01 +/- 0.08, 0.82 +/- 0.22, 0.6 +/- 0.15, and 0.32 +/- 0.08, respectively (p < 0.0001); the mean relMTT values were 1.04 +/- 0.14, 1.4 +/- 0.31, 2.16 +/- 0.46, and 3.3 +/- 0.54, respectively (p < 0.0001). All but one brain region (30 regions) with severe hypoperfusion on SPECT images demonstrated relCBF values less than 0.6 and relMTT values greater than 2.5 on perfusion CT scans.. Relative CBF and MTT values on perfusion CT showed a high concordance rate with estimated relCBF on SPECT in patients with vasospasm following aneurysmal SAH. Given its logistical advantages, perfusion CT may be a valuable method of assessing perfusion abnormality in the acute setting of vasospasm and in patients with an unstable condition following aneurysmal SAH.

Topics: Adult; Cysteine; Female; Humans; Intracranial Aneurysm; Male; Middle Aged; Organotechnetium Compounds; Radiography; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Subarachnoid Hemorrhage; Tomography, Emission-Computed, Single-Photon; Vasospasm, Intracranial

Cerebral vasospasm is a major cause of morbidity and mortality among patients after subarachnoid hemorrhage (SAH) from ruptured intracranial aneurysms. Patients are often monitored using transcranial Doppler (TCD) ultrasound and single photon emission computed tomography (SPECT) techniques. Historically SPECT has been evaluated qualitatively, though quantitative analysis software is now used to evaluate other cerebral pathologies.. Our aim was to evaluate the utility of semiquantitative SPECT using Hermes brain registration and analysis software (BRASS) relative to TCD ultrasound and qualitative SPECT interpretation within a cohort of patients, all with cerebral vasospasm as measured by digital subtraction angiography.. Retrospective analysis of 32 nonconsecutive patients, admitted for aneurysmal SAH examining perfusion deficits in terms of anterior, middle, and posterior vascular distributions using both TCD ultrasonography and brain perfusion SPECT studies.. McNemar analysis of accuracy between modalities showed a better overall performance trend for qualitative SPECT versus BRASS SPECT (Fisher exact = 0.99) and a statistically significant better performance of qualitative SPECT versus TCD in measuring anterior cerebral artery vasospasm (Fisher exact = 0.035). BRASS SPECT, however, performed better than qualitative SPECT in diagnosing posterior circulation vasospasm (Fisher exact = 0.180 vs. 0.358) and had greater specificity in determining anterior circulation vasospasm (71 vs. 57%).. BRASS SPECT is a useful method for evaluating cerebral perfusion and needs further optimization, particularly as it pertains to establishing semiquantitative cerebral perfusion parameters. It can serve as an adjunct to traditional SPECT evaluation of SAH particularly in determining subtle changes in the perfusion of the anterior and posterior arterial distributions.

Topics: Adult; Aged; Angiography, Digital Subtraction; Brain; Cohort Studies; Cysteine; Echoencephalography; Female; Humans; Image Interpretation, Computer-Assisted; Male; Middle Aged; Organotechnetium Compounds; Retrospective Studies; Software; Subarachnoid Hemorrhage; Tomography, Emission-Computed, Single-Photon; Ultrasonography, Doppler, Transcranial; Vasospasm, Intracranial; Young Adult

The purpose of this prospective study was to detect symptomatic cerebral vasospasm in aneurysmal subarachnoid haemorrhage (SAH) by a non-invasive mean cerebral blood flow (mCBF) quantification using 99mTc-ethyl cysteinate dimer. Measurement of mCBF without blood sampling and single photon emission tomography (SPECT) were performed at 1 and 7 days after surgery in 35 consecutive SAH patients, of whom 16 were examined at day 30 as well. A decrease in mCBF of more than 10% on day 7 versus day 1 was considered to indicate vasospasm. On visual interpretation of SPECT, a perfusion decrease which appeared newly on day 7 was considered to indicate vasospasm. In total, nine of 35 patients had cerebral vasospasm confirmed by computed tomography (CT) and/or angiography. The mCBF measurement showed a 77.8% (7/9) sensitivity, a 88.5% (23/26) specificity, a 70.0% (7/10) positive predictive value, and a 92.0% (23/25) negative predictive value. SPECT yielded a 33.3% (3/9) sensitivity, a 73.1% (19/26) specificity, a 30.0% (3/10) positive predictive value, and a 76.0% (19/25) negative predictive value. On SPECT, decreased perfusion was observed in most of the patients at clipping sites, which might represent post-operative transient abnormal perfusion and should not be read as vasospasm. In conclusion, this mCBF measurement is more accurate than visual interpretation of SPECT for detecting vasospasm.

Topics: Adult; Cerebral Angiography; Cerebrovascular Circulation; Cysteine; Female; Humans; Intracranial Aneurysm; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Subarachnoid Hemorrhage; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Vasospasm, Intracranial