Brain SPECT and transcranial doppler ultrasound in vasospasm-induced delayed cerebral ischemia after subarachnoid hemorrhage

Interventional endovascular therapy: SPECT cerebral blood flow imaging compared with transcranial doppler monitoring of balloon angioplasty and intraarterial papaverine for cerebral vasospasm

The effects of interventional endovascular treatment of cerebral vasospasm with balloon angioplasty or papaverine infusion were evaluated by single-photon emission computed tomography (SPECT) and transcranial Doppler (TCD) in 44 patients whose cerebral vasospasm was refractory to medical management. SPECT revealed blood flow improvements in 42% of patients with papaverine treated vessels and 70% of patients with balloon angioplasty (P=.037). TCD correlated with SPECT in 71% of patients in the papaverine group and 73% of patients in the balloon angioplasty group. TCD showed 93% of segments improved by angioplasty, whereas 43% of segments were improved with papaverine (P<.001). Disagreements were largely represented by patients with TCD velocity improvements in which SPECT blood flow imaging was, unchanged or worsened. Balloon angioplasty seems superior to papaverine infusion for treatment of vasospasm. SPECT and TCD are complementary tests in the evaluation of vasospasm and effect of interventional therapy.

Role of single photon emission computed tomography and transcranial Doppler ultrasonography in clinical vasospasm

This report presents our experience with Transcranial Doppler (TCD) ultrasonography and Single Photon Emission Computed Tomography (SPECT) in the assessment of patients with aneurysmal subarachnoid haemorrhage (SAH). It was designed to evaluate clinical vasospasm with both TCD and SPECT and determine their diagnostic value. Twenty-eight consecutive patients were examined with both TCD and SPECT, performed within 24 hours of each other. They had a total of 45 TCDs and 46 SPECT scans. Eight patients (29%) developed clinical vasospasm, noted from day 2 to day 11 post subarachnoid haemorrhage; these patients underwent TCDs and SPECT scans when the diagnosis of vasospasm was made. Twenty patients (71%) did not demonstrate clinical vasospasm throughout their hospital stay and underwent TCDs and SPECT scans within the first 2 weeks of their SAH, mostly between day 2 and day 10, the period of greatest risk for vasospasm. TCD and SPECT sensitivity for clinical vasospasm was 100% and 50% respectively, their specificity was only 20% and 60%. TCD sensitivity for symptomatic vasospasm was found to be excellent, whereas SPECT was not found to be as useful. We conclude that TCD is the preferred method in the evaluation of patients with subarachnoid haemorrhage.

Intracranial aneurysms and subarachnoid hemorrhage management of the poor grade patient

Between 20 and 30% of patients who suffer cerebral aneurysm rupture are in poor clinical grade when first evaluated. Management of these patients is controversial and challenging but can be successful with an aggressive proactive approach that begins with in the field resuscitation and continues through rehabilitation. In this article we review the epidemiology, pathology and pathophysiology, clinical features, evaluation, surgical and endovascular management, critical care, cost, and outcome prediction of patients in poor clinical grade after subarachnoid hemorrhage.

Effects of induced hypertension on transcranial Doppler ultrasound velocities in patients after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Transcranial doppler ultrasound (TCD) is used after subarachnoid hemorrhage to detect cerebral vasospasm and is often treated with induced hypertension. Cerebral autoregulation, however, may be disturbed in this population, raising the possibility that TCD velocities may be elevated by induced hypertension. To study this possibility, we performed continuous TCD monitoring of the middle cerebral artery during the induction and withdrawal of induced hypertension in patients after subarachnoid hemorrhage.

METHODS

Twenty-eight patients were studied during the induction and withdrawal of hypertension using primarily phenylephrine. Continuous monitoring was performed on the middle cerebral artery with the highest flow velocity. Treatment was based on rising TCD velocities or clinical evidence for cerebral vasospasm. Mean arterial pressure and mean TCD velocities were recorded every minute. A change of > 15% from starting TCD values was considered significant. Cerebral autoregulation was calculated as a percentage of intact autoregulation. Patients were subsequently divided into groups of disturbed and intact autoregulation.

RESULTS

In 10 of 19 patients (53%), TCD velocities changed by > 15% and paralleled changes in mean arterial pressure. This directly altered the TCD interpretation of the grade of vasospasm in 7 of 19 patients (36%). Three additional patients had smaller absolute changes in TCD velocities. No clinical difference could be identified between patients with disturbed and intact autoregulation.

CONCLUSIONS

In patients with disturbed autoregulation after subarachnoid hemorrhage, induced hypertension can alter cerebral blood flow velocities. The level of autoregulation needs to be considered when interpreting TCD velocities in patients after subarachnoid hemorrhage.

Delayed ischemia due to cerebral vasospasm occult to transcranial Doppler. An important role for cerebral perfusion SPECT

Cerebral vasospasm after subarachnoid hemorrhage is very common, but it is not universally detectable by transcranial Doppler. SPECT imaging of regional cerebral blood flow with Tc-99m exametazime serves as a complementary test to transcranial Doppler in the evaluation of patients at high risk for vasospasm. The significance of vasospasm, which may be underestimated by TCD, is readily identified with SPECT cerebral perfusion imaging.

Detection of intracranial internal carotid artery and middle cerebral artery vasospasm following subarachnoid hemorrhage

Little is known about the accuracy of transcranial Doppler (TCD) sonography in detecting intracranial internal carotid artery (IICA) and middle cerebral artery (MCA) vasospasm. TCD was performed in 49 patients with subarachnoid hemorrhage to evaluate 90 IICAs and 87 MCAs during the vasospasm period. When a mean velocity of at least 90 cm/sec was used to indicate IICA vasospasm, there were 11 positive, 42 negative, 4 false-positive, and 33 false-negative results. Sensitivity was 25% and specificity was 93%. When a mean velocity of at least 120 cm/sec was used to indicate MCA vasospasm, there were 15 positive, 45 negative, 3 false-positive, and 24 false-negative results (15 operator errors). Sensitivity was 38.5% and specificity was 93.7%. When the diagnostic criterion was changed to at least 130 cm/sec, specificities were 100% (IICA) and 96% (MCA) and positive predictive values were 100% (IICA) and 87% (MCA). The authors conclude that TCD accurately detects IICA and MCA vasospasm when flow velocities are at least 130 cm/sec. However, its sensitivity may be underestimated and the importance of operator error, overestimated.

Severe symptomatic vasospasm: the role of immediate postoperative angioplasty

The clinical success of angioplasty for symptomatic vasospasm following subarachnoid hemorrhage (SAH) depends on early intervention and can best be achieved after the aneurysm is occluded. However, patients presenting with unsecured ruptured aneurysms and established clinical vasospasm offer a dilemma for the surgeon. The authors describe the cases of five such patients who underwent acute clipping of aneurysms followed by immediate postoperative angioplasty between 1988 and 1992. All were referred at least 5 days after SAH. Severe vasospasm compatible with the clinical presentation was confirmed by angiography. The patients met the department's criteria for angioplasty but, because of unclipped aneurysms, were first taken patients met the department's criteria for angioplasty but, because of unclipped aneurysms, were first taken to the operating room for a craniotomy and aneurysm obliteration. Angiography was repeated immediately after surgery. Arterial narrowing had progressed during surgery in two patients. In all patients, postoperative mechanical dilatation was achieved with the use of a silicone microballoon. Following angioplasty, transcranial Doppler ultrasound flow velocities and single-photon emission computerized tomography evaluation indicated improved cerebral perfusion compared to preoperative determinations. Four patients improved clinically and made a good recovery. In this subgroup of patients presenting with proven symptomatic vasospasm and an unclipped but ruptured aneurysm, urgent surgical obliteration of the aneurysm followed by immediate postoperative angioplasty may be a safe and reasonable means to improve outcome.