CT Angiography, Head/Brain - CAM 727

Computed tomography angiography (CTA) is recognized as a valuable diagnostic tool for the management of patients with cerebrovascular disease. With its three-dimensional reconstructions, CTA can simultaneously demonstrate the bony skull base and its related vasculature. CTA use of ionizing radiation and an iodine-based intravascular contrast medium is a disadvantage when compared to magnetic resonance angiography (MRA) but it is quicker and requires less patient cooperation than MRA. CTA is much less invasive than catheter angiography which involves injecting contrast material into an artery.

CTA for Evaluation of Aneurysm – CTA is useful in the detection of cerebral aneurysms. The sensitivity of CTA to detect cerebral aneurysms < 5 mm is higher than that with digital subtraction angiography (DSA). Most aneurysms missed with CTA are< 3mm. Aneurysms in the region of the anterior clinoid process may extend into the subarachnoid space where they carry the threat of hemorrhage. CTA can help delineate the borders of the aneurysm in relation to the subarachnoid space and may help detect acute ruptured aneurysms. It may be used in the selection of patients for surgical or endovascular treatment of ruptured intracranial aneurysms.

CTA for Screening of Patients with first degree relative (parent, brother, sister or child) have a history of aneurysm – Data has suggested that individuals with a parent, brother, sister, or child harboring an intracranial aneurysm are at increased risk of aneurysms. It is likely that multiple genetic and environmental risk factors contribute to the increased risk.

CTA for evaluation of Arteriovenous Malformation (AVM) A good correlation has been found between catheter angiography and CTA in the detection of arteriovenous malformations. CTA allows calculation of the volume of an AVM nidus and identifies and quantifies embolic material within it. CTA may be used for characterization and stereotactic localization before surgical resection or radiosurgical treatment of arteriovenous malformations.

CTA and non-aneurysmal vascular malformations - Non-aneurysmal vascular malformations can be divided in low flow vascular malformations and high flow vascular malformations. Low flow vascular malformations include dural venous anomalies (DVA), cavernomas and capillary telangiectasias. High flow vascular malformations include AVM and dural arteriovenous fistulas (dAVF). For low flow malformations, MRI is the study of choice. There is limited medical literature to support vascular imagining (CTA or MRA). CTA plays a limited role in the assessment of cavernoma but may be used to demonstrate a DVA. MRA is not usually helpful in the assessment of cavernoma, capillary telangiectasia, and DVA. Vascular imaging is indicated in high flow vascular malformations. (ACR, 2017, 2019; Lee, 2012).  

CTA and recent stroke or transient ischemic attack - A stroke or central nervous system infarction is defined as ・brain, spinal cord, or retinal cell death attributable to ischemia, based on neuropathological, neuroimaging, and/or clinical evidence of permanent injury. … Ischemic stroke specifically refers to central nervous system infarction accompanied by overt symptoms, whereas silent infarction causes no known symptoms ・ (Sacco, 2013). If imaging or pathology is not available, a clinical stroke is diagnosed by symptoms persisting for more than 24 hours. Ischemic stroke can be further classified by the type and location of ischemia and the presumed etiology of the brain injury. These include large-artery atherosclerotic occlusion (extracranial or intracranial), cardiac embolism, small-vessel disease and less commonly dissection, hypercoagulable states, sickle cell disease and undetermined causes (Kernan, 2014). TIAs in contrast, ・are a brief episode of neurological dysfunction caused by focal brain or retinal ischemia, with clinical symptoms typically lasting less than one hour, and without evidence of acute infarction on imaging・ (Easton, 2009). On average, the annual risk of future ischemic stroke after a TIA or initial ischemic stroke is 34%, with an incidence as high as 11% over the next 7 days and 24-29% over the following 5 years. This has significantly decreased in the last half century due to advances in secondary prevention (Hong, 2011).

When revascularization therapy is not indicated or available in patients with an ischemic stroke or TIA, the focus of the work-up is on secondary prevention. This includes noninvasive vascular imaging to identify the underlying etiology, assess immediate complications and risk of future stroke. The majority of stroke evaluations take place in the inpatient setting. Admitting TIA patients is reasonable if they present within 72 hours and have an ABCD (2) score ≥3, indicating high risk of early recurrence, or the evaluation cannot be rapidly completed on an outpatient basis (Easton, 2009). Minimally, both stroke and TIA should have an evaluation for high-risk modifiable factors such as carotid stenosis atrial fibrillation as the cause of ischemic symptoms (Kernan, 2014). Diagnostic recommendations include: neuroimaging evaluation as soon as possible, preferably with magnetic resonance imaging, including DWI; noninvasive imaging of the extracranial vessels should be performed, and noninvasive imaging of intracranial vessels is reasonable (Wintermark, 2013).

Patients with a history of stroke and recent work up with new signs or symptoms indicating progression or complications of the initial CVA should have repeat brain imaging as an initial study. Patients with remote or silent strokes discovered on imaging should be evaluated for high-risk modifiable risk factors based on the location and type of the presumed etiology of the brain injury.

CTA for Evaluation of Vertebrobasilar Insufficiency (VBI) Multidetector CT angiography (MDCTA) may be used in the evaluation of vertebral artery pathologies. The correlation between MDCTA and color Doppler sonography is moderate. CTA is used for minimally invasive follow-up after intracranial stenting for VBI. It enables visualization of the patency of the stent lumen and provides additional information about all brain arteries and the brain parenchyma.

CTA and Intracerebral Hemorrhage CTA is useful as a screening tool for an underlying vascular abnormality in the evaluation of spontaneous intracerebral hemorrhage (ICH). Etiologies of spontaneous ICH include tumor, vascular malformation, aneurysm, hypertensive arteriopathy, cerebral amyloid angiopathy, venous thrombosis, vasculitis, RCVS, drug induced vasospasm, venous sinus thrombosis, Moyomoya disease, anticoagulant use and hemorrhagic transformation of an ischemic infarct. History can help point to a specific etiology. Possible risk factors for the presence of underlying vascular abnormalities include age younger than 65, female, lobar or intraventricular location, and the absence of hypertension or impaired coagulation (Delgado, 2009). 

CTV and Central Venous Thrombosis – a CT Venogram is indicted for the evaluation of a central venous thrombosis/dural sinus thrombosis. The most frequent presentations are isolated headache, intracranial hypertension syndrome, seizures, focal neurological deficits and encephalopathy. Risk factors are hypercoagulable states inducing genetic prothrombotic conditions, antiphospholipid syndrome and other acquired prothrombotic diseases such as cancer, oral contraceptives, pregnancy, puerperium (6 weeks postpartum), infections, and trauma. Since venous thrombosis can cause SAH, infarctions and hemorrhage parenchymal imaging with MRI/CT is also appropriate. (Bushnell, 2014; Courinho, 2015; Ferro, 2016; Waleki, 2015).

MRA and dissection - Craniocervical dissections can be spontaneous or traumatic. Patients with blunt head or neck trauma who meet Denver Screening criteria should be assessed for cerebrovascular injury (although about 20% will not meet criteria). The criteria include: focal or lateralizing neurological deficits (not explained by head CT), infarct on head CT, face, basilar skull, or cervical spine fractures, cervical hematomas that are not expanding, glasgow coma score less than 8 without CT findings, massive epistaxis, cervical bruit or thrill (Franz, 2012; Liang, 2013; Mundinger, 2013; Simon, 2019). Spontaneous dissection presents with headache, neck pain with neurological signs or symptoms. There is often minor trauma or precipitating factor (i.e., exercise, neck manipulation). Dissection is thought to occur due to weakness of the vessel wall and there may be an underlying connective tissue disorder. Dissection of the extracranial vessels can extend intracranially and/or lead to thrombus which can migrate into the intracranial circulation causing ischemia. Therefore, MRA of the head and neck is warranted (Nash, 2019; Shakir, 2016). 

BRAIN CTA is considered MEDICALLY NECESSARY for the following indications:

Brain CT/CTA are not approvable simultaneously unless they meet the criteria described below in the Indications for Brain CT/Brain CTA combination studies section. Patients with claustrophobia, limited ability to cooperate, or an implanted device may be better suited for CTA; whereas those with renal disease or iodine contrast allergy should have MRA (Chen, 2018).

For evaluation of suspected intracranial vascular disease (Robertson, 2020; Salmela, 2017):

Aneurysm screening

  • Screening for suspected intracranial aneurysm in patient with first-degree family history (parent, brother, sister, or child) of intracranial aneurysm

Note: Repeat study is recommended every 5 years (Chalouhi, 2011)

  • Screening for aneurysm in polycystic kidney disease (after age 30), Loeys-Dietz syndrome‡, fibromuscular dysplasia, spontaneous coronary arteries dissection (SCAD), or known aortic coarctation (Hayes, 2018; Hitchcock, 2016)

‡For Loeys-Dietz imaging should be repeated at least every two years

Vascular abnormalities 

  • Suspected vascular malformation (arteriovenous malformation (AVM) or dural arteriovenous fistula) in patient with previous or indeterminate imaging study
  • Thunderclap headache with continued concern for underlying vascular abnormality after initial negative work-up (Whitehead, 2019, Yeh, 2010, Yuan, 2018)
    • Negative Brain CT; AND Negative Lumbar Puncture; OR
    • Negative Brain MRI
  • Headache associated with exercise or sexual activity (ICHD-3, 2018)
  • Isolated third nerve palsy (oculomotor) with pupil involvement to evaluate for aneurysm (Pula, 2016) 
  • Pulsatile tinnitus to identify a vascular etiology (Hofmann, 2013; Pegge, 2017)

Note: MRI is the study of choice for detecting cavernomas (Morrison, 2016; Zyck, 2021)

Cerebrovascular Disease


  • Recent ischemic stroke or transient ischemic attack (See Background section) (Sanelli, 2014; Wintermark, 2013)
  • Known or suspected vertebrobasilar insufficiency (VBI) in patients with symptoms such as dizziness, vertigo, headaches, diplopia, blindness, vomiting, ataxia, weakness in both sides of the body, or abnormal speech (Lima-Neto 2017; Searls, 2012)


  • Known subarachnoid hemorrhage (SAH) (Colen, 2007)
  • Known cerebral intraparenchymal hemorrhage with concern for underlying vascular abnormality

Venous and MRV is contraindicated or cannot be performed-CTV** (Walecki, 2015)

  • Suspected venous thrombosis (dural sinus thrombosis) (Ferro, 2017; Saposnik, 2011)
  • Distinguishing benign intracranial hypertension (pseudotumor cerebri) from dural sinus thrombosis (Agarwal, 2010; Higgins 2005)

Sickle cells disease (ischemic and/or hemorrhagic) and MRV is contraindicated or cannot be performed (Thust, 2014)

  • Neurological signs or symptoms in sickle cell disease
  • Stroke risk in sickle cell patients (2 - 16 years of age) with a transcranial doppler velocity > 200

Vasculitis with initial laboratory workup (such as ESR, CRP, serology) (Berlit, 2014)

  • Suspected secondary CNS vasculitis based on neurological signs or symptoms in the setting of an underlying systemic disease with abnormal inflammatory markers or autoimmune antibodies
  • Suspected primary CNS vasculitis based on neurological signs and symptoms with completed infectious/inflammatory lab work-up (Godasi, 2019; Zuccoli, 2011)

Other intracranial vascular disease

  • Suspected Moyomoya disease (Ancelet, 2015; Tarasow, 2011).
  • Suspected reversible cerebral vasoconstriction syndrome (Singhal, 2016)
  • Giant cell arteritis with suspected intracranial involvement (Conway, 2018)

For evaluation of known intracranial vascular disease (Robertson, 2020; Salmela, 2017)

  • Known intracranial aneurysm or vascular malformation (i.e., AVM or dural arteriovenous fistula)
  • Vascular abnormality visualized on previous brain imaging that is equivocal or needs further evaluation
  • Known vertebrobasilar insufficiency with new or worsening signs or symptoms (VBI) (Lima-Neto, 2017; Searls, 2012)
  • Known vasculitis, reversible cerebral vasoconstriction syndrome or Moyomoya disease (Ancelet, 2015; Godasi, 2019; Signhal, 2016; Tarasow, 2011)

Pre-operative/procedural evaluation for brain/skull surgery

  • Pre-operative evaluation for a planned surgery or procedure

Post-operative/procedural evaluation (Sanelli, 2004; Wallace, 2007)

  • A follow-up study may be needed to help evaluate a patient’s progress after treatment, procedure, intervention, or surgery. Documentation requires a medical reason that clearly indicates why additional imaging is needed for the type and area(s) requested.

Indications for Brain CTA/Neck CTA combination studies

  • Recent ischemic stroke or transient ischemic attack (Sanelli, 2014)
  • Known or suspected vertebrobasilar insufficiency (VBI) in patients with symptoms such as dizziness, vertigo, headaches, diplopia, blindness, vomiting, ataxia, weakness in both sides of the body, or abnormal speech (Lima-Neto, 2017; Searls, 2012)
  • Suspected carotid or vertebral artery dissection; due to trauma or spontaneous due to weakness of vessel wall (Franz, 2012; Shakir, 2016)
  • Asymptomatic patients with an abnormal ultrasound of the neck or carotid duplex imaging (e.g.,carotid stenosis ≥ 70%, technically limited study, aberrant direction of flow in the carotid or vertebral arteries) and patient is surgery or angioplasty candidate (Brott, 2011; DaCosta, 2019; Marquardt, 2010)
  • Symptomatic patients with an abnormal ultrasound of the neck or carotid duplex imaging (e.g., carotid stenosis ≥ 50%, technically limited study, aberrant direction of flow in the carotid or vertebral arteries) and patient is surgery or angioplasty candidate (AAN, 2010; Brott, 2011; Rerkasem, 2011)
  • Pulsatile tinnitus to identify vascular etiology (Hofmann, 2013; Pegge, 2017)

Indications for Brain CT/Brain CTA combination studies (Robertson, 2020; Salmela, 2017)

  • Recent ischemic stroke or transient ischemic attack
  • Acute, sudden onset of headache with personal history of a vascular abnormality or first-degree family history of aneurysm
  • Headache associated with exercise or sexual activity when MRI is contraindicated or cannot be performed (ICHD-3, 2018)
  • Suspected venous thrombosis (dural sinus thrombosis) – CTV and MRI are contraindicated or cannot be performed

Indications for Brain CT/Brain CTA/Neck CTA combination studies 

  • Recent ischemic stroke or transient ischemic attack (TIA) (Robertson, 2020; Salmela, 2017)
  • Approved indications as noted above and being performed in high-risk populations (in whom MRI is contraindicated or cannot be performed) and will need anesthesia for the procedure and there is a suspicion of concurrent intracranial pathology


  1. American Academy of Neurology (AAN). Carotid Endarterectomy- An evidence-based review. 2010.
  2. Ancelet C, Boulouis G, Blauwblomme T, et al. Imaging Moya-Moya disease. Rev Neurol (Paris). 2015 Jan; 171(1):45-57. Epub 2014 Dec 30.
  3. Agarwal P, Kumar M, Arora V. Clinical profile of cerebral venous sinus thrombosis and the role of imaging in its diagnosis in patients with presumed idiopathic intracranial hypertension. Indian J Ophthalmol. 2010 Mar-Apr; 58(2):153-5.
  4. Berlit P, Kraemer M. Cerebral vasculitis in adults: what are the steps in order to establish the diagnosis? Red flags and pitfalls. Clin Exp Immunol. 2014; 175(3):419–424. doi:10.1111/cei.12221.
  5. Brott TG, Halperin JL, Abbara S, et al. 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline on the management of patients with extracranial carotid and vertebral artery disease: executive summary. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, and the American Stroke Association, American Association of Neuroscience Nurses, American Association of Neurological Surgeons, American College of Radiology, American Society of Neuroradiology, Congress of Neurological Surgeons, Society of Atherosclerosis Imaging and Prevention, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, Society for Vascular Medicine, and Society for Vascular Surgery. Circulation. 2011;124(4):489-532. doi:10.1161/CIR.0b013e31820d8d78.
  6. Bushnell C, Saposnik G. Evaluation and management of cerebral venous thrombosis. Continuum (Minneap Minn). 2014 Apr; 20(2 Cerebrovascular Disease):335-51.
  7. Chalouhi N, Chitale R, Jabbou P, et al. The case for family screening for intracranial aneurysms. Neurosurg Focus. December 2011; 31(6):E8.
  8. Chen X, Liu Y, Tong H, et al. Meta-analysis of computed tomography angiography versus magnetic resonance angiography for intracranial aneurysm. Medicine (Baltimore). 2018; 97(20):e10771.
  9. Colen TW, Wang LC, Ghodke BV, et al. Effectiveness of MDCT angiography for the detection of intracranial aneurysms in patients with nontraumatic subarachnoid hemorrhage. AJR Am J Roentgenol. 2007; 189:898-903. http://www.ajronline.org/doi/pdf/10.2214/AJR.07.2491.  
  10. Conway R, Smyth AE, Kavanagh RG, et al. Diagnostic utility of computed tomographic angiography in giant-cell arteritis. Stroke. 2018;49(9):2233-2236. doi:10.1161/STROKEAHA.118.021995.
  11. Courinho JM. Cerebral venous thrombosis. J Thromb Haemost. 2015 Jun; 13 Suppl 1:S238-44.
  12. DaCosta M, Tadi P, Surowiec SM. Carotid endarterectomy. In: StatPearls. StatPearls Publishing; 2021. Accessed August 4, 2021. http://www.ncbi.nlm.nih.gov/books/NBK470582/.
  13. Delgado Almondoz JE, Schaefer PW, Forero NP, et al. Diagnostic accuracy and yield of multidetector CT angiography in the evaluation of spontaneous intraparenchymal cerebral hemorrhage. AJNR Am J Neuroradiol. 2009 Jun; 30(6):1213-21. Epub 2009 Apr 2.
  14. Easton JD, Saver JL, Albers GW, et al. Definition and evaluation of transient ischemic attack: A scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease. The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists. Stroke. 2009 Jun; 40(6):2276-93.
  15. Edlow JA. Managing patients with nontraumatic, severe, rapid-onset headache. Ann Emerg Med. 2018 Mar; 71(3):400-408.
  16. Farsad K, Mamourian A, Eskey C, et al. Computed tomographic angiography as an adjunct to digital subtraction angiography for the pre-operative assessment of cerebral aneurysm. Open Neurology Journal. 2009; 3:1-7. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2682841/.
  17. Ferro JM, Bousser M-G, Canhão P, et al. European Stroke Organization guideline for the diagnosis and treatment of cerebral venous thrombosis - Endorsed by the European Academy of Neurology. Eur Stroke J. 2017;2(3):195-221. doi:10.1177/2396987317719364.
  18. Ferro JM, Canhão P, Aguiar de Sousa D. Cerebral venous thrombosis. La Presse Med. 2016 Dec; 45(12 Pt 2):e429-e450. Epub 2016 Nov 2.
  19. Franz RW, Willette PA, Wood MJ, et al. A systematic review and meta-analysis of diagnostic screening criteria for blunt cerebrovascular injuries. J Am Coll Surg. March 2012; 214(3):313-327.
  20. Godasi R, Bollu PC. Primary central nervous system vasculitis. [Updated 2019 May 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. https://www.ncbi.nlm.nih.gov/books/NBK482476/.  
  21. Hayes SN, Kim ESH, Saw J, et al. American Heart Association Council on Peripheral Vascular Disease; Council on Clinical Cardiology; Council on Cardiovascular and Stroke Nursing; Council on Genomic and Precision Medicine; and Stroke Council. Spontaneous Coronary Artery Dissection: Current State of the Science: A Scientific Statement from the American Heart Association. Circulation. 2018 May 8; 137(19:e523-e557. Epub 2018 Feb 22.
  22. Headache classification committee of the international headache society (IHS) the international classification of headache disorders, 3rd edition. Cephalalgia. 2018;38(1):1-211. doi:10.1177/0333102417738202.
  23. Higgins JN, Tipper G, Varley M, Pickard JD. Transverse sinus stenoses in benign intracranial hypertension demonstrated on CT venography. Br J Neurosurg. 2005 Apr; 19(2:137-40.
  24. Hitchcock E, Gibson WT. A review of the genetics of intracranial berry aneurysms and implications for genetic counseling. J Genet Couns. 2017 Feb; 26(1):21-31. Epub 2016 Oct 14.
  25. Hofmann E, Behr R, Neumann-Haefelin T, et al. Pulsatile tinnitus: Imaging and differential diagnosis. Deutsches Ärzteblatt International. 2013; 110(26):451-458. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3719451/.
  26. Hong KS, Yegiaian S, Lee M, et al. Declining stroke and vascular event recurrence rates in secondary prevention trials over the past 50 years and consequences for current trial design. Circulation. 2011 May 17; 123(19):2111-9. Epub 2011 May 2.
  27. Kernan WN, Ovbiagele B, Black HR, et al. Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014 Jul; 45(7):2160-236.
  28. Lee M, Kim MS. Image findings in brain developmental venous anomalies. J Cerebrovasc Endovasc Neurosurg. 2012 Mar; 14(1:37-43. Epub 2012 Mar 31.
  29. Liang T, Tso DK, Chiu RY, et al. Imaging of blunt vascular neck injuries: A review of screening and imaging modalities. AJR Am J Roentgenol. 2013 Oct; 201(4):884-92.
  30. Lima Neto AC, Bittar R, Gattas GS, et al. pathophysiology and diagnosis of vertebrobasilar insufficiency: A review of the literature. Int Arch Otorhinolaryngol. 2017; 21(3):302–307.
  31. Marquardt L, Geraghty OC, Mehta Z, Rothwell PM. Low risk of ipsilateral stroke in patients with asymptomatic carotid stenosis on best medical treatment: a prospective, population-based study. Stroke. 2010;41(1):e11-17. doi:10.1161/STROKEAHA.109.561837
  32. Morrison L, Akers A. Cerebral cavernous malformation, familial. In: Adam MP, Ardinger HH, Pagon RA, et al., eds. GeneReviews®. University of Washington, Seattle; 1993. Revised August 4, 2016. Accessed August 4, 2021. http://www.ncbi.nlm.nih.gov/books/NBK1293/.  
  33. Mundinger GS, Dorafshar AH, Gilson MM, et al. Blunt-mechanism facial fracture patterns associated with internal carotid artery injuries: recommendations for additional screening criteria based on analysis of 4,398 patients. J Oral Maxillofac Surg. December 2013; 71(12):2092-2100.
  34. Nash M, Rafay MF. Craniocervical arterial dissection in children: Pathophysiology and management. Pediatr Neurol. 2019 Jun; 95:9-18. Epub 2019 Feb 2.
  35. Pegge SAH, Steens SCA, Kunst HPM, et al. Pulsatile tinnitus: Differential diagnosis and radiological work-up. Curr Radiol Rep. 2017; 5(1):5.
  36. Pirau L, Lui F. Vertebrobasilar Insufficiency. [Updated 2019 Mar 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482259/.
  37. Pula JH, Kwan K, Yuen CA, Kattah JC. Update on the evaluation of transient vision loss. Clin Ophthalmol. 2016 Feb 11; 10:297–303.
  38. Rerkasem K, Rothwell PM. Carotid endarterectomy for symptomatic carotid stenosis. Cochrane Database Syst Rev. 2011;(4):CD001081. doi:10.1002/14651858.CD001081.pub2.
  39. Robertson RL, Palasis S, Rivkin MJ, et al. ACR Appropriateness Criteria® Cerebrovascular Disease-Child. J Am Coll Radiol. 2020;17(5S):S36-S54. doi:10.1016/j.jacr.2020.01.036.
  40. Sacco RL, Kasner SE, Broderick JP, et al. An updated definition of stroke for the 21st century: A statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2013 Jul; 44(7):2064-89.
  41. Salmela MB, Mortazavi S, Jagadeesan BD, et al. ACR Appropriateness Criteria ® Cerebrovascular Disease. J Am Coll Radiol. 2017;14(5S):S34-S61. doi:10.1016/j.jacr.2017.01.051.
  42. Sanelli PC, Mifsud MJ, Steig PE. Role of CT Angiography in guiding management decisions of newly diagnosed and residual arteriovenous malformations. AJR Am J Roentgenol. 2004; 183:1123-1126. http://www.ncbi.nlm.nih.gov/pubmed/15385318.
  43. Sanelli PC, Sykesa JB, Ford AL, et al. Imaging and treatment of patients with acute stroke: An evidence-based review. AJNR Am J Neuroradiol. 2014; 35:1045-1051.
  44. Saposnik G, Barinagarrementeria F, Brown RD, et al. Diagnosis and management of cerebral venous thrombosis: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2011;42(4):1158-1192. doi:10.1161/STR.0b013e31820a8364. 
  45. Searls DE, Pazdera L, Korbel E, Vysata O, Caplan LR. Symptoms and signs of posterior circulation ischemia in the new England medical center posterior circulation registry. Arch Neurol. 2012;69(3):346-351. doi:10.1001/archneurol.2011.2083.
  46. Shakir HJ, Davies JM, Shallwani H, et al. Carotid and vertebral dissection imaging. Curr Pain Headache Rep. 2016 Dec; 20(12):68.
  47. Simon LV, Mohseni M. Vertebral Artery Injury. StatPearls.Treasure Island, FL: StatPearls Publishing; 2019. https://www.ncbi.nlm.nih.gov/books/NBK470363/.
  48. Singhal AU, Topcuoglu MA, Fok JW, et al. Reversible cerebral vasoconstriction syndromes and primary angiitis of the central nervous system: Clinical, imaging, and angiographic comparison. Ann Neurol. 2016 Jun; 79(6):882-94. Epub 2016 Apr 28.
  49. Tarasów E, Kułakowska A, Lukasiewicz A, et al. Moyamoya disease: Diagnostic imaging. Pol J Radiol. 2011; 76(1):73–79.
  50. Thust SC, Burke C, Siddiqui A. Neuroimaging findings in sickle cell disease. Br J Radiol. 2014; 87(1040):20130699.
  51. Walecki J, Mruk B, Nawrocka-Laskus E, et al. Neuroimaging of cerebral venous thrombosis (cvt) - old dilemma and the new diagnostic methods. Pol J Radiol. 2015 Jul 25; 80:368–373.
  52. Wallace RC, Karis JP, et al. Non-invasive imaging of treated cerebral aneurysms, part II: CT angiographic follow-up of surgically clipped aneurysms. AJNR Am J Neuroradiol. August 2007; 28(7):1207-1212.
  53. Whitehead MT, Cardenas AM, Corey AS, et al. ACR Appropriateness Criteria® - Headache. J Am Coll Radiol. 2019; 16:S364-S377.
  54. Wintermark M, Sanelli PC, Albers GW, et al. Imaging recommendations for acute stroke and transient ischemic attack patients: A joint statement by the American Society of Neuroradiology, the American College of Radiology, and the Society of NeuroInterventional Surgery. AJNR Am J Neuroradiol. 2013 Nov-Dec; 34(11):E117-27. Epub 2013 Aug 1.
  55. Xu HW, Yu SQ, Mei CL, Li MH. Screening for intracranial aneurysm in 355 patients with autosomal-dominant polycystic kidney disease. Stroke. 2011;42(1):204-206. doi:10.1161/STROKEAHA.110.578740.
  56. Yeh YC, Fuh JL, Chen SP, et al. Clinical features, imaging findings and outcomes of headache associated with sexual activity. Cephalalgia. 2010 Nov; 30(11):1329-35.
  57. Yuan MK, Lai PH, Chen JY, et al. Detection of subarachnoid hemorrhage at acute and subacute/chronic stages: Comparison of four magnetic resonance imaging pulse sequences and computed tomography. J Chin Med Assoc. 2005 Mar; 68(3):131-7.
  58. Zuccoli G, Pipitone N, Haldipur A, et al. Imaging findings in primary central nervous system vasculitis. Clin Exp Rheumatol. 2011; 29(1 Suppl 64):S104-109.
  59. Zyck S, Gould GC. Cavernous venous malformation. In: StatPearls. StatPearls Publishing; 2021. Accessed August 4, 2021. http://www.ncbi.nlm.nih.gov/books/NBK526009/.

Coding Section 

Code Number Description
CPT 70496 Computed tomographic angiography, head, with contrast material(s), including noncontrast images, if performed, and image postprocessing

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each Policy. They may not be all-inclusive. 

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross and Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association.  All Rights Reserved" 

History From 2019 Forward     


Annual review, added criteria regarding giant cell arteritis, Loeys-Dietz, vertebrobasilar insufficiency and vasculitis.


Annual review, multiple additions and revisions to the policy criteria. Also updating description and references. 


New Policy

Complementary Content