This is the current release of the guideline.

This guideline updates a previous version: Davis PC, Brunberg JA, De La Paz RL, Dormont D, Jordan JE, Mukherji SK, Seidenwurm DJ, Turski PA, Wippold FJ II, Zimmerman RD, Sloan MA, Expert Panel on Neurologic Imaging. ACR Appropriateness Criteria® head trauma. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 13 p.

Head trauma

To evaluate the appropriateness of initial radiologic examinations for patients with head trauma

Patients with head trauma

Utility of radiologic examinations in differential diagnosis

Literature Search Procedure

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 American College of Radiology Appropriateness Criteria (ACR AC) 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.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the ACR Appropriateness Criteria® Evidence Table Development document (see the "Availability of Companion Documents" field).

Modified Delphi Technique

The appropriateness ratings for each of the procedures included in the Appropriateness Criteria topics are determined using a modified Delphi methodology. A series of surveys are conducted to elicit each panelist's expert interpretation of the evidence, based on the available data, regarding the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario. American College of Radiology (ACR) staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. The surveys are completed by panelists without consulting other panelists. The ratings are a scale between 1 and 9, which is further divided into three categories: 1, 2, or 3 is defined as "usually not appropriate"; 4, 5, or 6 is defined as "may be appropriate"; and 7, 8, or 9 is defined as "usually appropriate." Each panel member assigns one rating for each procedure per survey round. The surveys are collected and the results are tabulated, de-identified and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. Consensus is defined as eighty percent (80%) agreement within a rating category. The final rating is determined by the median of all the ratings once consensus has been reached. Up to three rating rounds are conducted to achieve consensus.

If consensus is not reached, the panel is convened by conference call. The strengths and weaknesses of each imaging procedure that has not reached consensus are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached on the call or when the document is circulated, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

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

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

ACR Appropriateness Criteria®

Clinical Condition: Head Trauma

Variant 1: Minor or mild acute closed head injury (GCS ≥13), without risk factors or neurologic deficit.

Radiologic Procedure	Rating	Comments	RRL*
CT head without contrast	7	Known to have low yield.
MRI head without contrast	4		O
MRA head and neck without contrast	3	Rarely indicated with mild trauma.	O
MRA head and neck without and with contrast	3		O
CT head without and with contrast	3
CTA head and neck with contrast	3	Rarely indicated with mild trauma.
MRI head without and with contrast	2		O
CT head with contrast	1
X-ray head	1
FDG-PET/CT head	1
US transcranial with Doppler	1		O
Arteriography cervicocerebral	1
Tc-99m HMPAO SPECT head	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 2: Minor or mild acute closed head injury, focal neurologic deficit and/or risk factors.

Radiologic Procedure	Rating	Comments	RRL*
CT head without contrast	9
MRI head without contrast	6	For problem solving.	O
MRA head and neck without contrast	5	If vascular injury is suspected. For problem solving.	O
MRA head and neck without and with contrast	5	If vascular injury is suspected. For problem solving. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CTA head and neck with contrast	5	If vascular injury is suspected. For problem solving.
MRI head without and with contrast	3		O
CT head without and with contrast	2
CT head with contrast	1
Tc-99m HMPAO SPECT head	1
FDG-PET/CT head	1
US transcranial with Doppler	1		O
X-ray head	1
Arteriography cervicocerebral	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 3: Moderate or severe acute closed head injury.

Radiologic Procedure	Rating	Comments	RRL*
CT head without contrast	9
MRI head without contrast	6		O
MRA head and neck without contrast	5		O
MRA head and neck without and with contrast	5	See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CTA head and neck with contrast	5
CT head without and with contrast	2
MRI head without and with contrast	2		O
X-ray head	2
CT head with contrast	1
US transcranial with Doppler	1		O
FDG-PET/CT head	1
Arteriography cervicocerebral	1
Tc-99m HMPAO SPECT head	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 4: Mild or moderate acute closed head injury, child <2 years old.

Radiologic Procedure	Rating	Comments	RRL*
CT head without contrast	9
MRI head without contrast	7	Diffusion weighted imaging especially helpful for nonaccidental trauma.	O
MRI head without and with contrast	4	Potentially useful in suspected nonaccidental trauma. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
MRA head and neck without contrast	4	If vascular abnormality suspected.	O
MRA head and neck without and with contrast	4	If vascular abnormality is suspected. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CTA head and neck with contrast	4	If vascular abnormality is suspected.
X-ray head	2	Appropriate as part of skeletal survey in suspected nonaccidental trauma. May be appropriate when screening for patients suspected of having penetrating head trauma or foreign bodies.
CT head without and with contrast	2
CT head with contrast	1
FDG-PET/CT head	1
Tc-99m HMPAO SPECT head	1
US transcranial with Doppler	1		O
Arteriography cervicocerebral	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 5: Subacute or chronic closed head injury with cognitive and/or neurologic deficit(s).

Radiologic Procedure	Rating	Comments	RRL*
MRI head without contrast	8		O
CT head without contrast	6
Tc-99m HMPAO SPECT head	4	For selected cases.
FDG-PET/CT head	4	For selected cases.
MRA head and neck without contrast	4	For selected cases.	O
MRA head and neck without and with contrast	4	For selected cases. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CTA head and neck with contrast	4	For selected cases.
MRI head without and with contrast	3		O
CT head without and with contrast	2
CT head with contrast	2
X-ray head	2
MRI functional (fMRI) head without contrast	2		O
US transcranial with Doppler	1		O
Arteriography cervicocerebral	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 6: Closed head injury, rule out carotid or vertebral artery dissection.

Radiologic Procedure	Rating	Comments	RRL*
CTA head and neck with contrast	8
MRA head and neck without contrast	8	Add T1 neck images.	O
MRA head and neck without and with contrast	8	Add T1 neck images. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
MRI head without contrast	8	Include diffusion-weighted images.	O
CT head without contrast	8
CT head without and with contrast	6	Consider perfusion.
Arteriography cervicocerebral	6	For problem solving.
MRI head without and with contrast	6	See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CT head with contrast	4	Consider perfusion.
X-ray head	2
Tc-99m HMPAO SPECT head	1
US transcranial with Doppler	1		O
FDG-PET/CT head	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 7: Penetrating injury, stable, neurologically intact.

Radiologic Procedure	Rating	Comments	RRL*
CT head without contrast	9
CTA head and neck with contrast	7
MRA head and neck without contrast	6	If there is no MRI contraindication.	O
MRA head and neck without and with contrast	6	If there is no MRI contraindication. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
Arteriography cervicocerebral	5	If vascular injury is suspected.
MRI head without contrast	5	If there is no MRI contraindication.	O
CT head without and with contrast	4	Consider perfusion.
MRI head without and with contrast	4	If there is no MRI contraindication. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
X-ray head	4
CT head with contrast	2
US transcranial with Doppler	1		O
Tc-99m HMPAO SPECT head	1
FDG-PET/CT head	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 8: Skull fracture.

Radiologic Procedure	Rating	Comments	RRL*
CT head without contrast	9
CTA head and neck with contrast	7	If vascular injury is suspected.
MRI head without contrast	6		O
X-ray head	5	For selected cases.
MRI head without and with contrast	4	Useful if infection suspected. See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CT head without and with contrast	4
MRA head and neck without contrast	4		O
MRA head and neck without and with contrast	4	See statement regarding contrast in the text below under "Anticipated Exceptions."	O
CT head with contrast	2
US transcranial with Doppler	1		O
Tc-99m HMPAO SPECT head	1
Arteriography cervicocerebral	1
FDG-PET/CT head	1
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

Introduction/Background

Craniocerebral injuries are a common cause of hospital admission following trauma, and are associated with significant long-term morbidity and mortality, particularly in the adolescent and young adult population. Neuroimaging plays an essential role in identifying and characterizing these brain injuries. Computed tomography (CT) remains essential for detecting lesions that require immediate neurosurgical intervention (e.g., acute subdural hematoma) as well as those that require in-hospital observation and medical management. For patients with minor head injury (Glasgow Coma Scale [GCS] score of 13-15), the New Orleans Criteria and the Canadian CT Head Rule are clinical guidelines with high sensitivity for detecting injuries that require neurosurgical intervention, and they offer a potential reduction in unnecessary CT scans. All guidelines have a trade-off between sensitivity and specificity for detection of significant findings in head-injured patients.

Other imaging modalities, such as magnetic resonance imaging (MRI), depict nonsurgical pathology not visible on CT. Single photon emission computed tomography (SPECT), positron emission tomography (PET), and transcranial Doppler (TCD) have a complementary role in the assessment of nonacute brain injury. Because cervical spine trauma may accompany a head injury, cervical spine imaging is indicated for patients with head injury who have signs, symptoms, or a mechanism of injury that might result in spinal injury, and in those who are neurologically impaired. See the National Guideline Clearinghouse (NGC) summary of American College of Radiology (ACR) Appropriateness Criteria® Suspected Spine Trauma for details.

Skull Radiography

One study developed and prospectively tested a management strategy for selecting patients who may benefit from skull radiography following head trauma was and offered recommendations for selecting patients who should receive CT scanning following head injury. The effect of that study was to shift the focus of neuroimaging of head trauma away from skull radiography and toward recognition of intracranial pathology as demonstrated by CT scanning. Skull radiography is useful for imaging of calvarial fractures, penetrating injuries, and radiopaque foreign bodies.

Computed Tomography

CT's advantages for evaluating the head-injured patient include its sensitivity for demonstrating mass effect, ventricular size and configuration, bone injuries, and acute hemorrhage regardless of location (i.e., parenchymal, subarachnoid, subdural, or epidural spaces). Other advantages include its widespread availability, rapidity of scanning, and compatibility with other medical and life support devices. Computer-generated reformatted images may have value in detecting intracranial hemorrhages, especially along bone surfaces that approximate the transverse plane of axial images.

CT limitations include insensitivity in detecting small and predominantly nonhemorrhagic lesions associated with trauma such as contusion, particularly when they are adjacent to bony surfaces (e.g., frontal lobes adjacent to the orbital roof, anterior temporal lobes adjacent to the greater sphenoid wing). Likewise, diffuse axonal injuries (DAIs) that result in small focal lesions throughout the cerebral hemispheres, corpus callosum, and upper brainstem and cerebellum often go undetected on CT. CT is relatively insensitive for detecting increased intracranial pressure or cerebral edema and for early demonstration of hypoxic-ischemic encephalopathy (HIE) that may accompany moderate or severe head injury. Potential risks of unnecessary exposure to ionizing radiation warrant judicious patient selection for CT scanning as well as radiation dose management.

There is now a general consensus that patients identified as having moderate or high risk for intracranial injury should undergo early postinjury noncontrast CT for evidence of intracerebral hematoma, midline shift, or increased intracranial pressure. A number of clinical criteria are used to predict patient risk categories for intracranial injury. There is an inverse relationship between declining clinical or neurologic status as described by the GCS and the incidence and severity of CT abnormalities related to head injury.

Although experienced physicians can often predict the likelihood of an abnormal CT scan in moderate or severe head injury, clinical selection criteria of patients with minor or mild injury (e.g., GCS score ≥13) who harbor significant intracranial pathology and/or require acute surgical intervention have been problematic. Rapid CT scanning is readily available in most hospitals that treat head-injured patients; thus the routine use of CT has been advocated as a screening tool to triage minor or mild head-injured patients who require hospital admission or surgical intervention from those who can be safely discharged without hospital admission. Although CT triage of head-injured patients who require hospital admission offers a reduced burden on inpatient hospital services at lower cost than routine hospital admission for observation, the result is greater CT use in the emergency setting. In the minor head injury setting with a GCS score of 15, the New Orleans Criteria found a 100% sensitivity for CT identification of an acute trauma lesion using risk factors of headache, vomiting, drug or alcohol intoxication, older than age 60, short-term memory deficit, physical findings of supraclavicular trauma, and/or seizure. One study reported 100% sensitivity for detecting neurosurgical and/or clinically important brain injury in subjects with a GCS score of 13-15 based on high-risk factors of failure to reach a GCS score of 15 within 2 hours, suspected open skull fracture, 2 or more vomiting episodes, sign of basal skull fracture, or age ≥65 years. A prospective trial of the Canadian CT Head Rule in Canadian emergency departments did not result in reduced rates of CT scanning in head trauma.

Clinical criteria for scanning of children with head injury have been less reliable than those for adults, particularly for children younger than age two. For this reason, more liberal use of CT scanning has been suggested for pediatric patients. On the other hand, this must be balanced with the higher risk of radiation exposure in childhood via judicious patient selection for scanning as well as size-based management of radiation dose. For pediatric patients, one study reported 95.4% sensitivity for intracranial injury using factors, including dizziness, skull defect, sensory deficit, mental status change, bicycle-related injury, age younger than 2 years, GCS score <15, and evidence of basilar skull fracture.

Noncontrast head CT plays an essential role in the evaluation of children with suspected physical injury from child abuse; appropriateness criteria for imaging of child abuse have already been described (see the pediatric sections of the ACR Appropriateness Criteria®).

Early and sometimes repeated CT scanning may be required in cases of clinical or neurologic deterioration, especially in the first 72 hours after head injury, to detect delayed hematoma, hypoxic-ischemic lesions, or cerebral edema. CT has a role in subacute or chronic head injury for depicting atrophy, focal encephalomalacia, hydrocephalus, and chronic subdural hematoma.

Cerebral Angiography, CT Angiography, and MR Angiography

Since the development of CT in the mid-1970s, the need for cerebral angiography for head injury has dramatically declined. Cerebral angiography has a role in demonstrating and managing traumatic vascular injuries such as pseudoaneurysm, dissection, fistulae, or diagnosis and neurointerventional treatment of uncontrolled hemorrhage. Vascular injuries typically occur with penetrating trauma (e.g., gunshot wound or stabbing), basal skull fracture, or trauma to the neck, although dissection and traumatic aneurysm may follow blunt or closed head trauma.

Dynamic spiral CT angiography (CTA) and magnetic resonance angiography (MRA) have a role as less invasive screening tools for detecting traumatic intracranial, skull base, and/or neck vascular lesions. Intracranial and neck MRA with fat-suppressed T1-weighted neck MR are helpful for screening vascular lesions such as thromboses, pseudoaneurysms, fistulae, or dissection. CTA of the aortic arch and neck vasculature may reveal carotid or vertebral dissection, although angiography remains the gold standard for depicting dissection. Independent predictors for arterial vascular injury as depicted by craniocerebral CTA in blunt trauma include cervical facet subluxation/dislocation, fracture lines approaching an artery, and high-impact injury mechanism. Cerebral infarction is an infrequent accompaniment of head injury, and patterns of infarction suggest that direct vascular compression related to intracranial mass lesions is the most common underlying mechanism.

Magnetic Resonance Imaging

MRI in imaging of head trauma is hindered by its limited availability in the acute trauma setting, long imaging times, sensitivity to patient motion, incompatibility with various medical and life support devices, and relative insensitivity to subarachnoid hemorrhage. Other factors include the need for MRI-specific monitoring equipment and ventilators, and the risk of scanning patients with certain indwelling devices (e.g., cardiac pacemaker, cerebral aneurysm clips) or occult foreign bodies. In part, these limitations can be overcome by situating MRI scanners close to emergency care areas with appropriate design and equipment for managing acutely injured patients. MRI advances such as open-bore geometry, faster imaging sequences, and improved patient monitoring equipment allow a greater role for MRI in closed head injuries.

MRI is very sensitive for detecting and characterizing subacute and chronic brain injuries. The number, size, and location of MR abnormalities in subacute head injury have been used to predict the recovery outcome of post-traumatic vegetative state. While CT is sensitive for detecting injuries requiring a change in treatment, MRI is also used for acute head-injured patients with nonsurgical, medically stable pathology. Hemosiderin-sensitive T2-weighted gradient echo and susceptibility-weighted sequences are helpful for imaging small or subacute or chronic hemorrhages. Diffusion-weighted sequences improve detection of acute infarction associated with head injury. Fluid-attenuated inversion recovery (FLAIR) images are more sensitive than conventional MRI sequences for depicting subarachnoid hemorrhage and for lesions bordered by cerebrospinal fluid (CSF). One study found that the addition of gadolinium enhancement offered no significant advantage for lesion detection or characterization compared with noncontrast MRI images in head-injury patients.

The soft tissue detail offered by MRI is superior to that of CT for depicting nonhemorrhagic primary lesions such as contusions, for detecting secondary effects of trauma such as edema and HIE, and for imaging of DAI. DAI results from a shear-strain pattern of acceleration-deceleration with characteristic lesions in increasing order of injury severity in the: 1) cerebral white matter and gray-white matter junction, 2) corpus callosum, particularly the splenium, and 3) dorsal upper brain stem and cerebellum.

Although management of surgical injuries is not likely to be altered by the substitution of MRI for CT, superior depiction of nonsurgical lesions with MRI may affect medical management and predict the degree of neurologic recovery. Early MRI (i.e., within 4 weeks) providing evidence of DAI following moderate to severe head trauma correlated with negative prognosis only in subjects with brain stem injury. Diffusion-weighted MRI and apparent diffusion coefficient (ADC) mapping depict cytotoxic injury almost immediately. In acute brain trauma, focal contusion and DAI may show restricted diffusion and evolve over time to atrophy or encephalomalacia. Perfusion imaging with CT or MRI may prove helpful as a marker for disorders of vascular autoregulation or ischemia. Diffusion tensor imaging and MR spectroscopy (MRS) are ancillary tools that may offer additional insight into the biochemical and structural patterns of injury following head trauma, as well as prognosis.

Functional Imaging Modalities

Some reports suggest that there is a role for functional imaging techniques (SPECT, PET, perfusion CT, perfusion MR, functional MRI, MRS) in assessing cognitive and neuropsychologic disturbances as well as recovery following head trauma. SPECT studies may reveal focal areas of hypoperfusion that are discordant with findings of MRI or CT. On the basis of these results, some investigators suggest that these functional imaging techniques may explain or predict post-injury neuropsychologic and cognitive deficits that are not explained by anatomic abnormalities detected by MRI or CT. Furthermore, focal lesions demonstrated by SPECT offer objective evidence of organic injury in patients whose neuroimaging studies are otherwise normal. One study found that a pattern of global reduction of cerebral blood flow detected by SPECT predicted a poor likelihood of recovery for patients who are in a persistent vegetative state due to head injury. Likewise, PET studies with fluorine-18-labeled fluorodeoxyglucose (FDG) tracer may reveal more extensive abnormalities than CT or MRI. SPECT and PET do not provide the anatomic detail or image resolution of CT or MRI for demonstrating acute or neurosurgical lesions of closed head injury, so their use is generally limited to subacute or chronic patients.

One reported study found that perfusion MRI may depict reduced blood volume in head-injured patients who do not show evidence of anatomic abnormalities on CT or MRI. Perfusion CT may likewise show abnormalities in cerebral blood flow after trauma that may correlate with outcome in mildly head-injured patients with disabling symptoms, although its clinical role is uncertain given the disadvantages of radiation exposure and its limited area of brain coverage. A reduction in N-acetylaspartate (NAA)/creatine ratio and NAA on MRS may occur in areas of brain injury, with lactate in areas of brain ischemia. MRS limitations include limited anatomic coverage and lack of correlation of ratios with outcome in mild head injury at 6 months.

TCD sonography offers a noninvasive bedside evaluation of cerebral blood flow velocity and resistance in the major proximal vessels of the circle of Willis. Several investigators have suggested that TCD can be used to monitor early changes in blood flow velocities that may relate to vasospasm, hypervolemia, low velocity state, or edema, especially in management of the acutely brain-injured patient.

Summary

• CT is the most appropriate initial study for acute evaluation of the head-injured patient who may harbor lesion(s) that require immediate neurosurgical intervention. Early and sometimes repeat CT scanning may be required if there is clinical and/or neurologic deterioration, especially in the first 72 hours after injury.
• Cervical spine imaging is often appropriate in head-injured patients. See the NGC summary of the ACR Appropriateness Criteria® Suspected Spine Trauma for details.
• MR has a role in subacute or chronic injury for detecting and characterizing non-neurosurgical lesions such as HIE and DAI, and may have a role in prognosis.
• Vascular imaging (CTA, MRA, and angiography) may depict traumatic vascular injuries in the setting of penetrating injury, blunt neck trauma, and/or skull base or cervical spine fracture.
• Advanced imaging techniques (perfusion CT, perfusion MRI, SPECT, and PET) have utility in better understanding selected head-injured patients but are not considered routine clinical practice at this time.

Anticipated Exceptions

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both underlying severe renal dysfunction and the administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73 m²), and almost never in other patients. There is growing literature regarding NSF. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73 m². For more information, please see the ACR Manual on Contrast Media (see the "Availability of Companion Documents" field).

Abbreviations

• CT, computed tomography
• CTA, computed tomography angiography
• FDG-PET, fluorodeoxyglucose-positron emission tomography
• GCS, Glasgow Coma Scale
• HMPAO, hexamethylpropyleneamine oxime
• MRA, magnetic resonance angiography
• MRI, magnetic resonance imaging
• SPECT, single photon emission tomography
• Tc, technetium
• US, ultrasound

Relative Radiation Level Designations

Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
	<0.1 mSv	<0.03 mSv
	0.1-1 mSv	0.03-0.3 mSv
	1-10 mSv	0.3-3 mSv
	10-30 mSv	3-10 mSv
	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as “Varies.”

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

Selection of appropriate radiologic imaging procedures for evaluation of patients with head trauma

Gadolinium-based Contrast Agents

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73 m²), and almost never in other patients. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73 m². For more information, please see the American College of Radiology (ACR) Manual on Contrast Media (see the "Availability of Companion Documents" field).

Relative Radiation Level (RRL)

Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, both because of organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for pediatric examinations are lower as compared to those specified for adults. Additional information regarding radiation dose assessment for imaging examinations can be found in the ACR Appropriateness Criteria® Radiation Dose Assessment Introduction document (see the "Availability of Companion Documents" field).

The American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U. S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

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

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Neurologic Imaging

Panel Members: Patricia C. Davis, MD (Principal Author); Franz J. Wippold II, MD (Panel Chair); Rebecca S. Cornelius, MD (Panel Vice-chair); Ashley H. Aiken, MD; Edgardo J. Angtuaco, MD; Kevin L. Berger, MD; Daniel F. Broderick, MD; Douglas C. Brown, MD; Annette C. Douglas, MD; Charles T. McConnell Jr, MD; Laszlo L. Mechtler, MD; J. Adair Prall, MD; Patricia B. Raksin, MD; Christopher J. Roth, MD; David J. Seidenwurm, MD; James G. Smirniotopoulos, MD; Alan D. Waxman, MD; Brian D. Coley, MD

Not stated

This is the current release of the guideline.

This guideline updates a previous version: Davis PC, Brunberg JA, De La Paz RL, Dormont D, Jordan JE, Mukherji SK, Seidenwurm DJ, Turski PA, Wippold FJ II, Zimmerman RD, Sloan MA, Expert Panel on Neurologic Imaging. ACR Appropriateness Criteria® head trauma. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 13 p.

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:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in PDF from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in PDF from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in PDF from the ACR Web site .
• ACR Appropriateness Criteria®. Manual on contrast media. Reston (VA): American College of Radiology; 90 p. Electronic copies: Available in PDF from the ACR Web site.
• ACR Appropriateness Criteria®. Procedure information. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in PDF from the ACR Web site.
• ACR Appropriateness Criteria® head trauma. Evidence table. Reston (VA): American College of Radiology; 2012. 28 p. Electronic copies: Available in PDF from the ACR Web site.

None available

This summary was completed by ECRI on July 31, 2001. The information was verified by the guideline developer as of August 24, 2001. This NGC summary was updated by ECRI on August 11, 2006. This NGC summary was updated by ECRI Institute on July 1, 2009. This summary was updated by ECRI Institute on January 13, 2011 following the U.S. Food and Drug Administration (FDA) advisory on gadolinium-based contrast agents. This NGC summary was updated by ECRI Institute on August 31, 2012.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .