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Clinical Policy Bulletin:
Computed Tomography Perfusion Imaging
Number: 0663


Policy

  1. Aetna considers cerebral computed tomography (CT) perfusion imaging experimental and investigational for assessing persons suspected of having an acute stroke or in triaging persons with stroke for thrombolytic therapy because there is inadequate published evidence that CT cerebral perfusion imaging improves outcomes over standard non-contrast CT scanning.

  2. Aetna considers CT cerebral perfusion imaging experimental and investigational for evaluating persons with chronic cerebral ischemia, cerebral vasospasm, head trauma, or as part of the balloon occlusion test or other indications because there is inadequate scientific evidence to support its use for these indications.


Background

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.

Currently, non-contrast computed tomography is used to detect intracerebral hemorrhage in stroke patients who are being considered for thrombolytic therapy.

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.  CT perfusion imaging may provide information about the presence and site of vascular occlusion, the presence and extent of ischemia, and about tissue viability.  This information may help the clinician determine whether thrombolysis is appropriate.

Potential advantages of CT perfusion imaging are that it can be performed using standard CT scanners, which are more widely available and less expensive than MRI, and it is less invasive than CT angiography.  CT perfusion imaging can be performed rapidly, and involves injection of a relatively small amount of contrast agent.

Current literature on CT perfusion imaging has focused on its feasibility and technical capabilities.  Prospective clinical studies are needed to determine the clinical value of CT perfusion imaging over standard non-contrast computed tomography in the assessment of patients with symptoms suggestive of acute stroke, and in the triage of patients in whom thrombolytic therapy is contemplated.

The Council on Cardiovascular Radiology of the American Heart Association provided guidelines and recommendations for perfusion imaging in cerebral ischemia (Latchaw et al, 2003).  It stated that quantitative CT perfusion may possibly be useful to differentiate between reversibly and irreversibly ischemic tissues in patients with acute stroke.  However, large prospective and appropriately blinded studies are needed to ascertain the value of this technique.  There are no data regarding the ability of this technique to predict the potential for hemorrhage following thrombolysis, as there is for the diffusible tracer techniques.  Furthermore, no recommendation can be made for the use of CT perfusion in patients with chronic ischemia, vasospasm, head trauma, or as part of the balloon occlusion test, the traditional method for identifying patients at risk for stroke.

In a review on imaging viable brain tissue with CT scan during acute stroke, Meuli (2004) stated that perfusion CT is now ready to be used in clinical trials as a decision-making tool to tailor more precisely the thrombolytic therapy to the individual patient.
 
CPT Codes / HCPCS Codes / ICD-9 Codes
CPT codes not covered for indications listed in the CPB:
0042T
Other CPT codes related to the CPB:
37195
61623
70450 - 70470
70496
ICD-9 codes not covered for indications listed in the CPB:
430 - 438.9 Cerebrovascular disease
800.00 - 804.99 Fracture of skull
850.00 - 854.19 Intracranial injury, excluding those with skull fracture
959.01 Head injury, unspecified


The above policy is based on the following references:
  1. Eastwood JD, Provenzale JM, Hurwitz LM, Lee TY. Practical injection-rate CT perfusion imaging: Deconvolution-derived hemodynamics in a case of stroke. Neuroradiol. 2001;43(3):223-226.
  2. Eastwood JD, Lev MH, Azhari T, et al. CT perfusion scanning with deconvolution analysis: Pilot study in patients with acute middle cerebral artery stroke. Radiology. 2002;222(1):227-236.
  3. Eastwood JD, Lev MH, Provenzale JM. Perfusion CT with iodinated contrast material. AJR Am J Roentgenol. 2003;180(1):3-12.
  4. Wintermark M, Maeder P, Verdun FR, et al. Using 80 kVp versus 120 kVp in perfusion CT measurement of regional cerebral blood flow. AJNR Am J Neuroradiol. 2000;21(10):1881-1884.
  5. Wintermark M, Thiran JP, Maeder P, et al. Simultaneous measurement of regional cerebral blood flow by perfusion CT and stable xenon CT: A validation study. AJNR Am J Neuroradiol. 2001;22(5):905-914.
  6. Koenig M, Kraus M, Theek C, et al. Quantitative assessment of the ischemic brain by means of perfusion-related parameters derived from perfusion CT. Stroke. 2001;32(2):431-437.
  7. Koenig M, Klotz E, Luka B, et al. Perfusion CT of the brain: Diagnostic approach for early detection of ischemic stroke. Radiology. 1998;209(1):85-93.
  8. Konig M. Brain perfusion CT in acute stroke: Current status. Eur J Radiol. 2003;45 Suppl 1:S11-S22.
  9. Kudo K, Terae S, Katoh C, et al. Quantitative cerebral blood flow measurement with dynamic perfusion CT using the vascular-pixel elimination method: Comparison with H(2)(15)O positron emission tomography. AJNR Am J Neuroradiol. 2003;24(3):419-426.
  10. Nabavi DG, Kloska SP, Nam EM, et al. MOSAIC: Multimodal Stroke Assessment Using Computed Tomography: Novel diagnostic approach for the prediction of infarction size and clinical outcome. Stroke. 2002;33(12):2819-2826.
  11. Bonaffini N, Altieri M, Rocco A, Di Piero V. Functional neuroimaging in acute stroke. Clin Exp Hypertens. 2002;24(7-8):647-657.
  12. Nabavi DG, Cenic A, Henderson S, et al. Perfusion mapping using computed tomography allows accurate prediction of cerebral infarction in experimental brain ischemia. Stroke. 2001;32(1):175-183.
  13. Klotz E, Konig M. Perfusion measurements of the brain: Using dynamic CT for the quantitative assessment of cerebral ischemia in acute stroke. Eur J Radiol. 1999;30(3):170-184.
  14. Muizelaar JP, Fatouros PP, Schroder ML. A new method for quantitative regional cerebral blood volume measurements using computed tomography. Stroke. 1997;28:1998-2005.
  15. Cenic A Nabavi DG, Craen RA, et al. Dynamic CT measurement of cerebral blood flow: A validation study. AJNR Am J Neuroradiol. 1999;20:63-73.
  16. Schellinger PD, Fiebach JB, Hacke W. Imaging-based decision making in thrombolytic therapy for ischemic stroke: Present status. Stroke. 2003;34(2):575-583.
  17. Rosand J, Eskey C, Chang Y, et al. Dynamic single-section CT demonstrates reduced cerebral blood flow in acute intracerebral hemorrhage. Cerebrovasc Dis. 2002;14(3-4):214-220.
  18. Keith CJ, Griffiths M, Petersen B, et al. Computed tomography perfusion imaging in acute stroke. Australas Radiol. 2002;46(3):221-230.
  19. Institute for Clinical Systems Improvement (ICSI). Diagnosis and initial treatment of ischemic stroke. Bloomington, MN: ICSI; October 2001.
  20. Hirsh J, Dalen J, Guyatt G. The sixth (2000) ACCP guidelines for antithrombotic therapy for prevention and treatment of thrombosis. American College of Chest Physicians. Chest. 2001;119(1 Suppl):1S-370S.
  21. Masaryk T, Drayer BP, Anderson RE, et al. Cerebrovascular disease. American College of Radiology. ACR Appropriateness Criteria. Radiology. 2000;215(Suppl):415-435.
  22. Miles KA. Acute cerebral stroke imaging and brain perfusion with the use of high-concentration contrast media. Eur Radiol. 2003;13 Suppl 5:M117-M120.
  23. Higashida RT, Furlan AJ, Roberts H, et al. Trial design and reporting standards for intra-arterial cerebral thrombolysis for acute ischemic stroke. Stroke. 2003;34(8):e109-e317.
  24. Latchaw RE, Yonas H, Hunter GJ, et al. 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;34(4):1084-104.
  25. Meuli RA. Imaging viable brain tissue with CT scan during acute stroke. Cerebrovasc Dis. 2004;17 Suppl 3:28-34.
  26. Hoeffner EG, Case I, Jain R, et al. Cerebral perfusion CT: Technique and clinical applications. Radiology. 2004;231(3):632-644.
  27. Mundy L, Merlin T, Parrella A. Perfusion CT scanning to evaluate cerebral perfusion in patients presenting with acute ischaemic stroke symptoms. Horizon Scanning Prioritising Summary - Volume 6. Adelaide, Australia: Adelaide Health Technology Assessment (AHTA) on behalf of National Horizon Scanning Unit (HealthPACT and MSAC); 2004.
  28. Kidwell CS, Hsia AW. Imaging of the brain and cerebral vasculature in patients with suspected stroke: Advantages and disadvantages of CT and MRI. Curr Neurol Neurosci Rep. 2006;6(1):9-16.
  29. Man K, Kareem AM, Ahmad Alias NA, et al. Computed tomography perfusion of ischaemic stroke patients in a rural Malaysian tertiary referral centre. Singapore Med J. 2006;47(3):194-197.
  30. Sviri GE, Mesiwala AH, Lewis DH, et al. Dynamic perfusion computerized tomography in cerebral vasospasm following aneurysmal subarachnoid hemorrhage: A comparison with technetium-99m-labeled ethyl cysteinate dimer-single-photon emission computerized tomography. J Neurosurg. 2006;104(3):404-410.
  31. Chen A, Shyr MH, Chen TY, et al. Dynamic CT perfusion imaging with acetazolamide challenge for evaluation of patients with unilateral cerebrovascular steno-occlusive disease. AJNR Am J Neuroradiol. 2006;27(9):1876-1881.
  32. Tan JC, Dillon WP, Liu S, et al. Systematic comparison of perfusion-CT and CT-angiography in acute stroke patients. Ann Neurol. 2007;61(6):533-543.
  33. Sparacia G, Iaia A, Assadi B, Lagalla R. Perfusion CT in acute stroke: Predictive value of perfusion parameters in assessing tissue viability versus infarction. Radiol Med (Torino). 2007;112(1):113-122.
  34. Kanazawa R, Kato M, Ishikawa K, et al. Convenience of the computed tomography perfusion method for cerebral vasospasm detection after subarachnoid hemorrhage. Surg Neurol. 2007;67(6):604-611.


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Copyright Aetna Inc. All rights reserved. Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.
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