Does the location of the arterial input function affect quantitative CTP in patients with vasospasm?

BACKGROUND AND PURPOSE: In recent years, there has been increasing use of CTP imaging in patients with aneurysmal SAH to evaluate for vasospasm. Given the critical role of the arterial input function for generation of accurate CTP data, several studies have evaluated the effect of varying the arterial input function location in patients with acute stroke. Our aim was to determine the effect on quantitative CTP data when the arterial input function location is distal to significant vasospasm in patients with aneurysmal SAH. MATERIALS AND METHODS: A retrospective study was conducted of patients with aneurysmal SAH admitted from 2005 to 2011. Inclusion criteria were the presence of at least 1 anterior cerebral artery or MCA vessel with a radiologically significant vasospasm and at least 1 of these vessels without vasospasm. We postprocessed each CTP dataset 4 separate times by using standardized methods, only varying the selection of the arterial input function location in the anterior cerebral artery and MCA vessels. For each of the 4 separately processed examinations for each patient, quantitative data for CBF, CBV, and MTT were calculated by region-of-interest sampling of the vascular territories. Statistical analysis was performed by using a linear mixed-effects model. RESULTS: One hundred twelve uniquely processed CTP levels were analyzed in 28 patients (mean age, 52 years; 24 women and 4 men) recruited from January 2005 to December 2011. The average Hunt and Hess scale score was 2.89 ± 0.79. The average time to CTP from initial presentation was 8.2 ± 5.1 days. For each vascular territory (right and left anterior cerebral artery, MCA, posterior cerebral artery), there were no significant differences in the quantitative CBF, CBV, and MTT generated by arterial input function locations distal to significant vasospasm compared with nonvasospasm vessels (P > .05). CONCLUSIONS: Arterial input function placement distal to significant vasospasm does not affect the quantitative CTP data in the corresponding vascular territory or any other vascular territory in aneurysmal SAH.

Evaluating CT perfusion using outcome measures of delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: DCI is a serious complication following aneurysmal SAH and remains a leading cause of morbidity and mortality. Our aim was to evaluate CTP in aneurysmal SAH by using outcome measures of DCI. MATERIALS AND METHODS: This was a retrospective study of consecutive patients with SAH enrolled in a prospective institutional review board-approved clinical accuracy trial. Qualitative CTP deficits were determined by 2 neuroradiologists blinded to clinical and imaging data. Quantitative CTP was performed by using a standardized protocol with region-of-interest placement sampling of the cortex. Primary outcome measures were permanent neurologic deficits and infarction. The secondary outcome measure was DCI, defined as clinical deterioration. CTP test characteristics (95% CI) were determined for each outcome measure. Statistical significance was calculated by using the Fisher exact and Student t tests. ROC curves were generated to determine accuracy and threshold analysis. RESULTS: Ninety-six patients were included. Permanent neurologic deficits developed in 33% (32/96). CTP deficits were seen in 78% (25/32) of those who developed permanent neurologic deficits and 34% (22/64) of those without (P < .0001). CTP deficits had 78% (61%-89%) sensitivity, 66% (53%-76%) specificity, and 53% (39%-67%) positive and 86% (73%-93%) negative predictive values. Infarction occurred in 18% (17/96). CTP deficits were seen in 88% (15/17) of those who developed infarction and 41% (32/79) of those without (P = .0004). CTP deficits had an 88% (66%-97%) sensitivity, 59% (48%-70%) specificity, and 32% (20%-46%) positive and 96% (86%-99%) negative predictive values. DCI was diagnosed in 50% (48/96). CTP deficits were seen in 81% (39/48) of patients with DCI and in 17% (8/48) of those without (P < .0001). CTP deficits had 81% (68%-90%) sensitivity, 83% (70%-91%) specificity, and 83% (70%-91%) positive and 82% (69%-90%) negative predictive values. Quantitative CTP revealed significantly reduced CBF and prolonged MTT for DCI, permanent neurologic deficits, and infarction. ROC analysis showed that CBF and MTT had the highest accuracy. CONCLUSIONS: CTP may add prognostic information regarding DCI and poor outcomes in aneurysmal SAH.

Meaningful Use.

A brief review of the Meaningful Use incentive program for eligible professionals is presented, highlighting the legislative history, criteria, and incentive payment plan of the program. Clinical measures applicable to radiology practice and the barriers to implementation are discussed. Resources are also provided for further information on the requirements and enrollment of the program.

Hospital Outpatient Prospective Payment System.

A brief review of the Hospital Outpatient Prospective Payment System (HOPPS) is presented highlighting the program's legislative history, outpatient service classifications and payment plan. Specifically, HOPPS measures applicable to imaging practices are discussed. Resources are also provided for further information on the program requirements and the ambulatory payment classifications (APC) system.

Hospital Outpatient Quality Data Reporting Program.

A brief review of the Hospital Outpatient Quality Data Reporting Program (HOP QDRP) is presented highlighting the program's legislative history, outpatient imaging efficiency measures and program requirements. Specifically, HOP QDRP measures applicable to imaging practices are discussed. Resources are also provided for further information on the program's requirements and measures.

Physician Quality Reporting System.

A brief review of the Physician Quality Reporting System (PQRS) is presented highlighting the program's legislative history, eligibility requirements and incentive payment plan. Specifically, PQRS measures applicable to neuroradiology practice are discussed. Several steps are suggested for individual physicians or group practices to start participation in the program. Resources are also provided for further information on the program requirements and PQRS measures.