The widespread availability and utilization of CTP

Although computer tomography perfusion (CTP) imaging is being investigated more and more as a stroke therapy biomarker, its wide-spread availability and utilization is still uncertain. In this retrospective large-cohort study of 50,797 acute ischemic stroke cases in the Texas area, results showed that CTP imaging was only used in 3% of the cases. Moreover, CTP images were assessed in only 17% of the patients treated with endovascular therapy. It should be noted that 14% of the Texas hospitals were CTP-performing in 2017 with most centers being located in urban areas. Based on the rather low CTP utilization, the authors argue for the necessity of developing and validating alternative means to effectively and timely screen stroke patients for endovascular and/or intravenous treatments.

Utilization and Availability of Advanced Imaging in Patients With Acute Ischemic Stroke

Youngran Kim, Songmi Lee, Rania Abdelkhaleq, Victor Lopez-Rivera, Babak Navi, Hooman Kamel, Sean I. Savitz, Alexandra L. Czap, James C. Grotta, Louise D. McCullough, Trudy Millard Krause, Luca Giancardo, Farhaan S. Vahidy, Sunil A. Sheth


Background: Recent clinical trials have established the efficacy of endovascular stroke therapy and intravenous thrombolysis using advanced imaging, particularly computed tomography perfusion (CTP). The availability and utilization of CTP for patients and hospitals that treat acute ischemic stroke (AIS), however, is uncertain.

Methods: We performed a retrospective cross-sectional analysis using 2 complementary Medicare datasets, full sample Texas and 5% national fee-for-service data from 2014 to 2017. AIS cases were identified using International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision coding criteria. Imaging utilization performed in the initial evaluation of patients with AIS was derived using Current Procedural Terminology codes from professional claims. Primary outcomes were utilization of imaging in AIS cases and the change in utilization over time. Hospitals were defined as imaging modality-performing if they submitted at least 1 claim for that modality per calendar year. The National Medicare dataset was used to validate state-level findings, and a local hospital-level cohort was used to validate the claims-based approach.

Results: Among 50 797 AIS cases in the Texas Medicare fee-for-service cohort, 64% were evaluated with noncontrast head CT, 17% with CT angiography, 3% with CTP, and 33% with magnetic resonance imaging. CTP utilization was greater in patients treated with endovascular stroke therapy (17%) and intravenous thrombolysis (9%). CT angiography (4%/y) and CTP (1%/y) utilization increased over the study period. These findings were validated in the National dataset. Among hospitals in the Texas cohort, 100% were noncontrast head CT-performing, 77% CT angiography-performing, and 14% CTP-performing in 2017. Most AIS cases (69%) were evaluated at non-CTP-performing hospitals. CTP-performing hospitals were clustered in urban areas, whereas large regions of the state lacked immediate access.

At Nicolab we believe CTP adds true value for the physician and ultimately the stroke patient. CTP helps a physician to identify the size of the core and penumbra, and therefore helps to determine how much tissue is salvageable through reperfusion therapy. We really hope in the near future more hospitals will utilize the advantage of CTP in their clinics. Our automated CTP algorithm is included in the StrokeViewer solution. Noise reduction and quality checks help to ensure results are consistent and reliable. Find out more here. (link to CTP page/portfolio).

Conclusions: In state-wide and national Medicare fee-for-service cohorts, CTP utilization in patients with AIS was low, and most patients were evaluated at non-CTP-performing hospitals. These findings support the need for alternative means of screening for AIS recanalization therapies.

Reference to paper: 

Kim, Y., Lee, S., Abdelkhaleq, R., Lopez-Rivera, V., Navi, B., Kamel, H., Savitz, S., Czap, A., Grotta, J., McCullough, L., Krause, T., Giancardo, L., Vahidy, F. and Sheth, S., 2021. Utilization and Availability of Advanced Imaging in Patients With Acute Ischemic Stroke. Circulation: Cardiovascular Quality and Outcomes,.