Download Cerebral Perfusion Analysis using Computed Tomography

Medical Policy
Cerebral Perfusion Analysis using
Computed Tomography (CT)
Effective Date: April, 2006;
Revised [05/09; 04/11; 5/13; 5/15]
Subject: Cerebral Perfusion Analysis using Computed Tomography (CT)
Overview: Computed tomography (CT) perfusion imaging provides a quantitative measurement of regional
cerebral blood flow. A perfusion CT study involves sequential acquisition of CT sections during intravenous
administration of an iodinated contrast agent. Analysis of the results allows the physician to calculate the
regional cerebral blood volume, the blood mean transit time through the cerebral capillaries, and the regional
cerebral blood flow. CT perfusion imaging has been proposed to be used primarily as a method of evaluating
patients suspected of having an acute stroke whenever thrombolysis is considered.
Policy and Coverage Criteria:
Cerebral Perfusion Analysis using Computed Tomography is NOT covered by HPHC. It is considered
investigational/experimental and unproven.
Exclusions: N/A
Supporting Information:
1. Technology Assessment: Perfusion computed tomography is an imaging modality that uses a contrast agent
to provide quantitative measurements of regional cerebral blood flow. Maps of cerebral blood volume, mean
transit time, and cerebral blood flow can be obtained from a pixel-by-pixel analysis of the density changes over
time. The maps generated depend on the commercial software and algorithms used in the processing of the
data.
2. Literature Review: Available clinical evidence does not support the use of CT cerebral perfusion analysis.
Rawal et al. (2015) conducted an analysis on the effectiveness of diagnostic strategies in suspected delayed
cerebral ischema. Diagnostic testing to assess for perfusion deficits included CT perfusion. The authors concluded
that imaging studies to test for the presence of perfusion deficits in patients with clinical delayed cerebral
ischemia do not seem helpful in selecting which patients should undergo treatment and may not improve
outcomes. Sun et al. (2014) conducted a meta-analysis of 3 articles to evaluate the diagnostic accuracy of CT
perfusion and CT perfusion parameters for vasospasm after aneurysm rupture. The authors concluded that CT
perfusion has a great diagnostic value to detect cerebral vasospasm in patients with aneurismal subarachnoid
hemorrhage. Bendinelli et al. (2013) conducted an analysis of an ongoing prospective observational study on
trauma patients with severe traumatic brain injury (STBI) to determine the role of brain CT perfusion imaging.
When compared to non-contrast CT, CTperfusion provided additional diagnostic information in 60% of the
patients but only altered clinical management in 10% of the patients.
Obach and colleagues (2011) compared the outcomes of 106 subjects with acute stroke who were assessed with
multimodal CT (CT angiography CTA/CT perfusion) to 262 subjects with acute stroke who were assessed without
full multimodal brain imaging during a 5-year period. The two groups were similar at baseline with the exception
of a greater percentage of participants with a time-to-treatment of greater than 3 hours (28% vs. 16%) and a
greater percentage treated with endovascular therapy (26% vs. 11%, respectively) in the multimodal CT group.
At three months, 56% of participants assessed by multimodal CT demonstrated good outcomes (defined as a
modified Rankin scale score less than or equal to 2 at 90 days) in comparison with 41% of controls (p=0.008).
In a sensitivity analysis, multimodal- CT assisted thrombolysis yielded superior benefits in those subjects treated
after 3 hours (adjusted OR, 4.48) than for subjects treated within 3 hours (adjusted OR, 1.31). For subjects
treated after 3 hours, 63% of those assessed by multimodal CT demonstrated good outcomes in comparison with
24% of the control group. Symptomatic hemorrhage (5% and 7%) and mortality (14% and 15%, both
respectively) were similar in both groups. The authors concluded the use of multimodal CT in routine clinical
practice may heighten overall efficacy of thrombolytic therapy in acute ischemic stroke, but noted additional
randomized clinical trials are needed.
A 2008 systematic review by Provenzale et al. focused on both CT and MRI perfusion imaging in the assessment
of acute cerebrovascular disease. The review found literature provided important insights into the physiologic
processes underlying acute cerebral ischemia by correlation of initial perfusion imaging deficits with clinical
outcome or ultimate size of the infarct. However, the studies did not show a clear role of perfusion imaging in
clinical decision making. Provenzale et al. noted more studies are needed to demonstrate that use of perfusion
imaging changes outcomes of patients with acute cerebral ischemia.
A 2005 AHRQ Technology Assessment noted CT and MR imaging for patient selection and prediction of outcome
in thrombolysis has yet to be prospectively evaluated. The two included CT studies differ in onset to evaluation
time with only a weak correlation between CT changes and outcome seen in the trial enrolling patients from 0-6
hours. Neither study quantified CT changes.
Wintermark et al. (2005) reported on the results of 46 patients with suspected acute hemispheric stroke
underwent non-enhanced CT and dynamic perfusion CT, with follow-up CT or MR imaging. Sensitivity, specificity,
accuracy were compared. Non-enhanced CT and PCT data were reviewed for stroke extent according to
previously reported methods. Results showed that compared with non-enhanced CT, PCT maps were significantly
more accurate in detecting stroke. Wintermark et al. concluded that despite limited spatial coverage, PCT is
highly reliable to assess the stroke extent.
Wintermark et al. (2004) conducted a clinical trial to determine the prognostic accuracy of perfusion computed
tomography (CT), performed at the time of emergency room admission, in acute stroke patients. Accuracy was
determined by comparison of perfusion CT with delayed magnetic resonance (MR) and by monitoring the
evolution of each patient's clinical condition. 22 acute stroke patients underwent perfusion CT covering four
contiguous 10mm slices on admission, as well as delayed MR, performed after a median interval of 3 days after
emergency room admission. Eight were treated with thrombolytic agents. Infarct size on the admission perfusion
CT was compared with that on the delayed diffusion-weighted (DWI)-MR, chosen as the gold standard. Delayed
magnetic resonance angiography and perfusion-weighted MR were used to detect recanalization. A potential
recuperation ratio, defined as PRR = penumbra size/(penumbra size + infarct size) on the admission perfusion
CT, was compared with the evolution in each patient's clinical condition, defined by the National Institutes of
Health Stroke Scale (NIHSS). In the 8 cases with arterial recanalization, the size of the cerebral infarct on the
delayed DWI-MR was larger than or equal to that of the infarct on the admission perfusion CT, but smaller than
or equal to that of the ischemic lesion on the admission perfusion CT; and the observed improvement in the
NIHSS correlated with the PRR (correlation coefficient = 0.833). In the 14 cases with persistent arterial occlusion,
infarct size on the delayed DWI-MR correlated with ischemic lesion size on the admission perfusion CT (r =
0.958). In all 22 patients, the admission NIHSS correlated with the size of the ischemic area on the admission
perfusion CT (r = 0.627). Based on these findings, the authors concluded that perfusion CT allows the accurate
prediction of the final infarct size and the evaluation of clinical prognosis for acute stroke patients at the time of
emergency evaluation. It may also provide information about the extent of the penumbra. Perfusion CT could
therefore be a valuable tool in the early management of acute stroke patients. Hoeffner et al. (2004) noted in a
review of the clinical applications of cerebral perfusion CT that some controversies exist regarding this technique,
including which artery to use as input vessel, the accuracy of quantitative results, and the reproducibility of
results. A 2008 review by Sajjad noted that, “perfusion imaging enables the physician to directly estimate the
tissue at risk which can be salvaged with reperfusion, enabling appropriate patient selection. Perfusion imaging
however has its limitations which need to be kept in mind when these studies are interpreted. Although perfusion
imaging is widely used, the evidence to support its routine use in acute stroke is somewhat sparse and therefore
there are no clear cut guidelines as to its role in this context.”
3. Professional/Governmental Agencies:
American Heart Association/ American Stroke Association Stroke Council, Clinical Cardiology Council,
Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and
Quality of Care Outcomes in Research Interdisciplinary Working Groups: The role of perfusion CT and CT
angiography in making acute treatment decisions has not yet been established.
http://stroke.ahajournals.org/cgi/reprint/38/5/1655
CMS: No National Coverage Determination
Codes:
CPT Codes:
0042T:
Cerebral perfusion analysis using computed tomography with contrast administration, including postprocessing of parametric maps with determination of cerebral blood flow, cerebral blood volume, and
mean transit time
References:
1. American College of Radiology (ACR) and the American Society of Neuroradiology (ASNR). Practice
Parameter for the performance of CT Perfusion in Neuroradiologic Imaging. October, 2007. Amended 2014.
http://www.acr.org/~/media/ACR/Documents/PGTS/guidelines/CT_Perfusion.pdf
2. AHA guidelines Guidelines and recommendations for perfusion imaging in cerebral ischemia: A scientific
statement for healthcare professionals by the writing group on perfusion imaging, from the Council on
Cardiovascular Radiology of the American Heart Association. Stroke. 2003 Apr;34(4):1084-104.
3. Provenzale, JM., Shah, K., Patel, U., McCrory, DC. Systematic review of CT and MR perfusion imaging for
assessment of acute cerebrovascular disease. AJNR Am J Neuroradiol. 2008; 29(8): 1476-82
4. Sharma, M., Clark, H., Armour, T., Stotts, G., Cote, R., et al. Acute stroke: evaluation and treatment. Evid
Rep Technol Assess. 2005; July(127):1-7.
http://www.ahrq.gov/downloads/pub/evidence/pdf/acutestroke/acstroke.pdf
5. Wintermark, M., Fischbein, NJ., Smith, WS., Ko NU., Quist, M., Dillon, WP. Accuracy of dynamin perfusion CT
with deconvolution in detecting acute hemispheric stroke. Am J Neuroradiol. 2005; 26(1): 104-12.
6. Wintermark M, Reichhart M, Thiran JP, Maeder P, Chalaron M, Schnyder P, Bogousslavsky J, Meuli R.
Prognostic accuracy of cerebral blood flow measurement by perfusion computed tomography, at the time of
emergency room admission, in acute stroke patients. Ann Neurol. 2002 Apr;51(4):417-32.
7. Koenig M, Kraus M, Theek C, Klotz E, Gehlen W, Heuser L. Quantitative assessment of the ischemic brain by
means of perfusion-related parameters derived from perfusion CT. Stroke. 2001 Feb;32(2):431-7.
8. Hoeffner, EG., Case, I., Jain, R., Gujar, SK., Shah, GV., Develikis, JP., et al. Cerebral perfusion CT: technique
and clinical applications. Radiology. 2004; 231(3): 632-44.
9. Sajjad, Z. Perfusion imaging in icshaemic stroke. J Pak Med Assoc. 2008; 58(7): 391-4.
10. Adams HP, del Zoppo G, Alberts MJ, et al. Guidelines Update: Guidelines for the Early Management of Adults
With Ischemic Stroke: A Guideline From the American Heart Association/ American Stroke Association Stroke
Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the
Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary
Working Groups: Stroke, 2007; 38: 1655 – 1711.
11. Xyda, A., Haberland, U., Klotz, E., et al. Brain volume perfusion CT performed with 128-detector row CT
system in patients with cerebral gliomas: a feasibility study. Eur Radio. 2011; 21(9): 1811-9.
12. Oback, V., Oleaga, L., Urra, X., Macho, J., et al. Multimodal Ct-assisted thrombolysis in patients with acute
stroke: a cohort study. Stroke. 2011; 42(4):
13. Rawal, S., Barnett, C., John-Baptiste, A., Thein, HH., Krings, T., Rinkel, GJ. Effectiveness of diagnostic
strategies in suspected delayed cerebral ischemia: a decision analysis. Stroke. 2015; 46(1):77-83.
14. Sun, H., Zhang, H., Ma, J., Liu, Y., You, C. Evaluating the diagnostic accuracy of CT perfusion in patients with
cerebral vasospasm after aneurysm rupture: a meta-analysis. Turk Neurosurg. 2014; 24(5):757-62.
15. Bendinelli, C., Bivard, A., Nebauer, S., Parsons, MW., Balogh, ZZJ. Brain CT perfusion provides additional
useful information in severe traumatic brain injury. Injury. 2013; 44(9):1208-12.
Summary of Changes
Date
Change
4/17
Removed Benchmarks