This is the current release of the guideline.

Abnormalities of the brain

Note: Refer to the "Indications" section of the "Major Recommendations" field for a detailed list of diseases and conditions.

Adult and pediatric patients undergoing computed tomography (CT) of the brain

Not stated

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the Practice Guideline or Technical Standard topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Not applicable

Not stated

Recommendations are formulated through iterative review by committee, collaborating societies, and membership. Suggested recommendations are reviewed by the committee, and agreement is reached by consensus.

Not applicable

A formal cost analysis was not performed and published costs analyses were not reviewed.

Each practice guideline and technical standard, representing a policy statement by the American College of Radiology (ACR), has undergone a thorough consensus process in which it has been subjected to extensive review, requiring the approval of the Commission on Quality and Safety as well as the ACR Board of Chancellors, the ACR Council Steering Committee, and the ACR Council.

Computed tomography (CT) is a technology extensively used in neuroradiology that produces cross-sectional displays using ionizing radiation to generate images resulting from X-ray absorption by the specific tissues examined. CT offers a high degree of utility in the examination of the brain. This guideline outlines the principles for performing high-quality CT imaging of the brain in pediatric and adult patients, including advanced applications such as CT perfusion, CT volumetry, CT angiography, and CT venography.

Indications

Indications for CT of the brain include, but are not limited to:

1. Primary Indications
   1. Acute head trauma
   2. Suspected acute intracranial hemorrhage
   3. Vascular occlusive disease or vasculitis (including use of CT angiography and/or venography)
   4. Aneurysm evaluation
   5. Detection or evaluation of calcification
   6. Immediate postoperative evaluation following surgical treatment of tumor, intracranial hemorrhage, or hemorrhagic lesions
   7. Treated or untreated vascular lesions
   8. Suspected shunt malfunctions, or shunt revisions
   9. Mental status change
   10. Increased intracranial pressure
   11. Headache
   12. Acute neurologic deficits
   13. Suspected intracranial infection
   14. Suspected hydrocephalus
   15. Congenital lesions (such as, but not limited to, craniosynostosis, macrocephaly, and microcephaly)
   16. Evaluating psychiatric disorders
   17. Brain herniation
   18. Suspected mass or tumor

2. Secondary Indications
   1. When magnetic resonance imaging (MRI) is unavailable or contraindicated, or if the supervising physician deems CT to be appropriate
   2. Diplopia
   3. Cranial nerve dysfunction
   4. Seizures
   5. Apnea
   6. Syncope
   7. Ataxia
   8. Suspicion of neurodegenerative disease
   9. Developmental delay
   10. Neuroendocrine dysfunction
   11. Encephalitis
   12. Drug toxicity
   13. Cortical dysplasia, and migration anomalies or other morphologic brain abnormalities

For the pregnant or potentially pregnant patient, see the "ACR Practice Guideline for Imaging Pregnant or Potentially Pregnant Adolescents and Women with Ionizing Radiation" (see the American College of Radiology [ACR] Web site for this practice guideline and additional ones mentioned below.)

Qualification and Responsibilities of Personnel

See the "ACR Practice Guideline for Performing and Interpreting Diagnostic Computed Tomography (CT)."

Specifications of the Examination

The supervising physician must have complete understanding of the indications, risks, and benefits of the examination, as well as alternative imaging procedures. The physician should be familiar with relevant ancillary studies that the patient may have undergone (see the "ACR Practice Guideline for Communication of Diagnostic Imaging Findings"). The physician performing CT interpretation must have a clear understanding and knowledge of the anatomy and pathophysiology relevant to the examination.

The written or electronic request for CT of the brain should provide sufficient information to demonstrate the medical necessity of the examination and allow for its proper performance and interpretation.

Documentation that satisfies medical necessity includes 1) signs and symptoms and/or 2) relevant history (including known diagnoses). Additional information regarding the specific reason for the examination or a provisional diagnosis would be helpful and may at times be needed to allow for the proper performance and interpretation of the examination.

The request for the examination must be originated by a physician or other appropriately licensed health care provider. The accompanying clinical information should be provided by a physician or other appropriately licensed health care provider familiar with the patient's clinical problem or question and consistent with the state's scope of practice requirements. (ACR Resolution 35, adopted in 2006)

1. General Considerations

   CT protocols for brain imaging should be designed to answer the specific clinical question. The supervising physician should be familiar with the indications for each examination, relevant patient history, potential adverse reactions to contrast media, exposure factors, window and center settings, field of view, collimation, slice intervals, slice spacing (table increment) or pitch, and image reconstruction algorithms. Protocols should be reviewed and updated periodically to optimize the examination.

2. Brain Imaging

   CT brain imaging may be performed with a sequential single-slice technique, multislice helical (spiral) protocol, or multidetector multislice algorithm. For CT of the brain, contiguous or overlapping axial slices should be acquired with a slice thickness of no greater than 5 mm. In the setting of trauma, images should be obtained and/or reviewed at window settings appropriate for demonstrating brain and bone abnormalities as well as small subdural hematomas and soft tissue lesions (subdural windows). For imaging of the cranial base, an axial slice thickness as thin as possible, but no greater than 3 mm with spiral techniques and 2 mm with multidetector and nonspiral techniques, should be used for 2-dimensional (2D) reformatting or for 3-dimensional (3D) reconstruction.

3. Contrast Studies

   Certain indications require administration of intravenous (IV) contrast media or intrathecal contrast (e.g., cisternography) during imaging of the brain. Intravenous contrast enhancement should be performed using appropriate injection protocols and in accordance with the "ACR Practice Guideline for the Use of Intravascular Contrast Media." Cerebrospinal fluid (CSF) contrast administration requires use of nonionic agents approved for intrathecal use and should be performed with regard to applicable guidelines as outlined in the "ACR–ASNR Practice Guideline for the Performance of Myelography and Cisternography."

4. Advanced Applications

   In addition to directly acquired axial images, reformatted images in coronal, sagittal, or other more complex planes may be constructed from the axial data set to answer specific clinical questions, or the images may be manipulated to allow selective visualization of specific tissues such as in CT perfusion, CT volumetry, CT angiography, or CT venography. Such applications are better performed with helical data sets using very thin slice thickness and overlapping reconstruction rather than routine axial sequential data. See the "ACR–ASNR Practice Guideline for the Performance of Computed Tomography (CT) Perfusion in Neuroradiologic Imaging."

Documentation

Reporting should be in accordance with the "ACR Practice Guideline for Communication of Diagnostic Imaging Findings."

Equipment Specifications

See the original guideline document for information about equipment specifications.

Radiation Safety in Imaging

Radiologists, medical physicists, radiologic technologists, and all supervising physicians have a responsibility to minimize radiation dose to individual patients, to staff, and to society as a whole, while maintaining the necessary diagnostic image quality. This concept is known as "as low as reasonably achievable (ALARA)."

Facilities, in consultation with the medical physicist, should have in place and should adhere to policies and procedures, in accordance with ALARA, to vary examination protocols to take into account patient body habitus, such as height and/or weight, body mass index or lateral width. The dose reduction devices that are available on imaging equipment should be active; if not, manual techniques should be used to moderate the exposure while maintaining the necessary diagnostic image quality. Periodically, radiation exposures should be measured and patient radiation doses estimated by a medical physicist in accordance with the appropriate ACR Technical Standard. (ACR Resolution 17, adopted in 2006 – revised in 2009, Resolution 11)

None provided

The type of supporting evidence is not specifically stated for each recommendation.

Improved performance of computed tomography (CT) of the brain

Quality Control and Improvement, Safety, Infection Control, and Patient Education

Policies and procedures related to quality, patient education, infection control, and safety should be developed and implemented in accordance with the American College of radiology (ACR) Policy on Quality Control and Improvement, Safety, Infection Control, and Patient Education appearing under the heading Position Statement on QC & Improvement, Safety, Infection Control, and Patient Education on the ACR Web site .

For specific issues regarding computed tomography (CT) quality control, see the "ACR Practice Guideline for Performing and Interpreting Diagnostic Computed Tomography (CT)" (see the ACR Web site ).

Equipment monitoring should be in accordance with the ACR Technical Standard for Diagnostic Medical Physics Performance Monitoring of Computed Tomography (CT) Equipment (see the ACR Web site ).

Not applicable: The guideline was not adapted from another source.

American College of Radiology

Guidelines and Standards Committee of the Commission on Neuroradiology in collaboration with the Subcommittee on Standards and Guidelines of the American Society of Neuroradiology (ASNR)

Principal Drafter: John E. Jordan, MD

American College of Radiology (ACR) Guidelines and Standards Committee: Suresh K. Mukherji, MD, FACR (Chair); Jacqueline A. Bello, MD, FACR; Mark H. Depper, MD; Carol A. Dolinskas, MD, FACR; Sachin Gujar, MD; John E. Jordan, MD; Stephen A. Kieffer, MD, FACR; Edward J. O'Brien, Jr., MD, FACR; Jeffrey R. Petrella, MD; John L. Ulmer, MD; R. Nick Bryan, MD, PhD, FACR (Chair, Commission)

American Society of Neuroradiology (ASNR) Guidelines Committee: Suresh K. Mukherji, MD, FACR (Chair); John D. Barr, MD; Jacqueline A. Bello, MD, FACR; Carol A. Dolinskas, MD, FACR; Kavita K. Erickson, MD; Scott H. Faro, MD; Blaise V. Jones, MD; John E. Jordan, MD; Edward E. Kassel, MD, FACR; Stephen A. Kieffer, MD, FACR; Eric J. Russell, MD, FACR; Jeffrey A. Stone, MD; Robert W. Tarr, MD; Patrick A. Turski, MD, FACR

Comments Reconciliation Committee: Michael M. Raskin, MD, MPH, JD, MBA, FACR (Chair); Kimberly E. Applegate, MD, MS, FACR; Howard B. Fleishon, MD, MMM, FACR; John E. Jordan, MD; Alan D. Kaye, MD, FACR; Paul A. Larson, MD, FACR; Lawrence A. Liebscher, MD, FACR; Carolyn C. Meltzer, MD, FACR; Suresh K. Mukherji, MD, FACR; Christopher J. Roth, MD; Michael I. Rothman, MD; Lawrence N. Tanenbaum, MD, FACR

Not stated

This is the current release of the guideline.

Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• The process of developing ACR practice guidelines and technical standards. Reston (VA): American College of Radiology. Electronic copies: Available from the American College of Radiology (ACR) Web site .
• Purpose and intended use. Reston (VA): American College of Radiology. Electronic copies: Available from the ACR Web site .

None available

This NGC summary was completed by ECRI Institute on October 13, 2011.

Copyright © by the American College of Radiology, 1891 Preston White Dr., Reston, VA 20191-4397, 703-648-8900. All rights reserved. No reproduction of this material in any format, electronic or otherwise, is permitted except with prior written consent from the American College of Radiology.