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Variant 1: Sudden, severe headache or “worst headache of life”. Initial imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
CT head without IV contrast Usually appropriate Strong ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 9 9 0 0 0 0 0 0 0 0 15
References Study Quality
31 (25863687) 3
32 (27306497) Good
33 (21768192) 1
34 (25862794) 2
35 (26797666) M
36 (16436770) 4
CTA head with IV contrast May be appropriate (Disagreement) Expert Opinion ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 5 5 0 3 0 2 4 5 2 0 0
MRA head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 3 3 6 1 2 1 3 1 1 0 0
MRA head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 2 2 6 4 6 0 0 0 0 0 0
MRI head without IV contrast Usually not appropriate Limited O 0 mSv O 0 mSv [ped] 2 2 6 3 7 0 0 0 0 0 0
References Study Quality
37 (16628051) 2
38 (15090339) 4
MRI head without and with IV contrast Usually not appropriate Limited O 0 mSv O 0 mSv [ped] 2 2 6 3 7 0 0 0 0 0 0
References Study Quality
37 (16628051) 2
38 (15090339) 4
CT head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 1 1 8 3 3 0 1 0 0 0 0
CT head without and with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 8 3 1 2 1 0 0 0 0
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 13 2 0 0 0 0 0 0 1
Variant 2: New headache with optic disc edema. Initial imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
MRI head without and with IV contrast Usually appropriate Limited O 0 mSv O 0 mSv [ped] 8 8 0 0 0 0 2 1 4 4 4
References Study Quality
51 (27928402) 4
52 (22309765) 2
CT head without IV contrast Usually appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 7 7 0 0 0 1 1 0 8 1 5
References Study Quality
46 (27679541) 2
47 (21293023) 4
MRI head without IV contrast Usually appropriate Limited O 0 mSv O 0 mSv [ped] 7 7 0 0 1 0 2 4 5 2 1
References Study Quality
51 (27928402) 4
52 (22309765) 2
MRV head without IV contrast May be appropriate Limited O 0 mSv O 0 mSv [ped] 6 6 0 0 0 2 6 7 1 0 0
References Study Quality
53 (28104635) 2
CTV head with IV contrast May be appropriate Strong ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 6 6 0 0 1 1 1 5 6 0 1
References Study Quality
48 (10094346) 2
49 (18437434) 2
50 (17114562) 2
MRV head without and with IV contrast May be appropriate Limited O 0 mSv O 0 mSv [ped] 6 6 0 0 1 0 2 6 1 0 5
References Study Quality
53 (28104635) 2
CT head with IV contrast May be appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 4 4 0 1 1 7 4 3 0 0 0
References Study Quality
46 (27679541) 2
47 (21293023) 4
CT head without and with IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 2 2 7 4 5 0 0 0 0 0 0
References Study Quality
46 (27679541) 2
47 (21293023) 4
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 13 1 1 0 0 0 0 0 0
Variant 3: New or progressively worsening headache with one or more of the following ‘red flags’: subacute head trauma, related activity or event (sexual activity, exertion, position), neurological deficit, known or suspected cancer, immunosuppressed or immunocompromised state, currently pregnant, or 50 years of age or older. Initial imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
CT head without IV contrast Usually appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 9 9 0 0 0 0 0 1 2 2 10
MRI head without and with IV contrast Usually appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 8 8 0 0 0 0 1 1 4 4 5
MRI head without IV contrast Usually appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 7 7 0 1 0 0 1 1 6 2 4
CTA head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 3 3 6 1 4 0 2 1 1 0 0
CT head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 3 3 5 2 9 0 0 0 0 0 0
MRA head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 3 3 6 1 4 1 1 2 0 0 0
CT head without and with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 2 2 8 1 4 2 0 1 0 0 0
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 12 0 3 0 0 0 0 0 0
MRA head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 10 2 4 0 0 0 0 0 0
Variant 4: New headache. Classic migraine or tension-type primary headache. Normal neurologic examination. Initial imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
CTA head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 10 3 0 0 2 0 0 0 0
CT head with IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 1 1 10 1 3 1 0 0 0 0 0
References Study Quality
81 (8035914) 4
CT head without IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 1 1 10 3 2 1 0 0 0 0 0
References Study Quality
81 (8035914) 4
CT head without and with IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 9 3 0 2 1 0 0 0 0
References Study Quality
81 (8035914) 4
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 15 0 0 0 0 0 0 0 0
MRA head without IV contrast Usually not appropriate Limited O 0 mSv O 0 mSv [ped] 1 1 10 1 1 1 1 0 1 0 0
References Study Quality
88 (15885388) 4
MRA head without and with IV contrast Usually not appropriate Limited O 0 mSv O 0 mSv [ped] 1 1 10 1 1 2 0 0 1 0 0
References Study Quality
88 (15885388) 4
MRI head without IV contrast Usually not appropriate Strong O 0 mSv O 0 mSv [ped] 1 1 9 3 4 0 0 0 0 0 0
References Study Quality
82 (22268442) 2
83 (27190013) 1
84 (25896482) 3
85 (16006538) 2
86 (27441999) 4
87 (20198381) 4
MRI head without and with IV contrast Usually not appropriate Strong O 0 mSv O 0 mSv [ped] 1 1 14 1 1 0 0 0 0 0 0
References Study Quality
82 (22268442) 2
83 (27190013) 1
84 (25896482) 3
85 (16006538) 2
86 (27441999) 4
87 (20198381) 4
MRV head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 10 1 3 0 1 0 0 0 0
CTV head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 10 3 1 0 1 0 0 0 0
MRV head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 10 1 3 0 1 0 0 0 0
Variant 5: New primary headache of suspected trigeminal autonomic origin. Initial imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
MRI head without and with IV contrast Usually appropriate Limited O 0 mSv O 0 mSv [ped] 7 7 1 0 0 1 2 3 2 2 4
References Study Quality
90 (20462914) 4
93 (26092512) 4
MRI head without IV contrast May be appropriate Limited O 0 mSv O 0 mSv [ped] 5 5 0 0 2 2 5 6 1 0 0
References Study Quality
90 (20462914) 4
93 (26092512) 4
CT head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 2 2 5 3 3 1 1 2 0 0 0
CT head without IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 2 2 5 4 7 0 0 0 0 0 0
MRA head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 2 2 7 1 2 2 1 1 1 0 0
MRA head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 2 2 7 2 1 2 2 1 0 0 0
CTA head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 8 4 1 1 0 1 0 0 0
CT head without and with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 9 2 1 0 1 2 0 0 0
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 14 1 0 0 0 0 0 0 0
Variant 6: Chronic headache. No new features. No neurologic deficit. Initial imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
CT head without IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 3 3 4 1 6 1 1 1 1 0 0
References Study Quality
22 (24266337) 4
23 (15606567) 3
81 (8035914) 4
98 (19687093) Good
99 (16256141) 2
100 (29560060) 4
MRI head without IV contrast Usually not appropriate Moderate O 0 mSv O 0 mSv [ped] 2 2 7 3 3 2 1 0 0 0 0
References Study Quality
22 (24266337) 4
23 (15606567) 3
81 (8035914) 4
98 (19687093) Good
99 (16256141) 2
MRI head without and with IV contrast Usually not appropriate Moderate O 0 mSv O 0 mSv [ped] 2 2 8 2 4 1 1 0 0 0 0
References Study Quality
22 (24266337) 4
23 (15606567) 3
81 (8035914) 4
98 (19687093) Good
99 (16256141) 2
CTA head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 10 3 0 1 1 0 0 0 0
CT head with IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 1 1 8 2 4 1 0 0 0 0 0
References Study Quality
22 (24266337) 4
23 (15606567) 3
81 (8035914) 4
98 (19687093) Good
99 (16256141) 2
100 (29560060) 4
CT head without and with IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 9 2 1 2 1 0 0 0 0
References Study Quality
22 (24266337) 4
23 (15606567) 3
81 (8035914) 4
98 (19687093) Good
99 (16256141) 2
100 (29560060) 4
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 15 0 0 0 0 0 0 0 0
MRA head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 9 4 0 1 0 1 0 0 0
MRA head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 10 3 0 1 1 0 0 0 0
MRV head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 10 3 1 0 0 1 0 0 0
CTV head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 10 3 1 0 1 0 0 0 0
MRV head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 11 2 1 0 1 0 0 0 0
Variant 7: Chronic headache. New features or increasing frequency. Initial Imaging.
Procedure Appropriateness Category SOE Adult RRL Peds RRL Rating Median Final Tabulations
1 2 3 4 5 6 7 8 9
MRI head without and with IV contrast Usually appropriate Limited O 0 mSv O 0 mSv [ped] 9 9 0 0 0 0 1 0 2 4 8
References Study Quality
22 (24266337) 4
103 (-3145949) 4
MRI head without IV contrast Usually appropriate Limited O 0 mSv O 0 mSv [ped] 7 7 0 0 1 0 1 2 4 1 6
References Study Quality
22 (24266337) 4
103 (-3145949) 4
CT head without IV contrast May be appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 6 6 0 1 0 1 3 3 3 1 3
References Study Quality
22 (24266337) 4
103 (-3145949) 4
CT head without and with IV contrast May be appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 4 4 5 0 0 5 5 0 0 0 0
References Study Quality
22 (24266337) 4
103 (-3145949) 4
CT head with IV contrast Usually not appropriate Limited ☢☢☢ 1-10 mSv ☢☢☢ 0.3-3 mSv [ped] 2 2 7 2 3 1 0 2 0 0 0
References Study Quality
22 (24266337) 4
103 (-3145949) 4
MRA head without IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 2 2 7 1 4 0 2 1 0 0 0
CTA head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 9 1 1 0 3 1 0 0 0
Arteriography cervicocerebral Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 14 0 1 0 0 0 0 0 0
MRA head without and with IV contrast Usually not appropriate Expert Consensus O 0 mSv O 0 mSv [ped] 1 1 9 0 4 0 2 0 0 0 0
CTV head with IV contrast Usually not appropriate Expert Consensus ☢☢☢ 1-10 mSv ☢☢☢☢ 3-10 mSv [ped] 1 1 9 2 0 1 1 1 1 0 0
Appendix Key

A more complete discussion of the items presented below can be found by accessing the supporting documents at the designated hyperlinks.

Appropriateness Category:The panel’s recommendation for a procedure based on the assessment of the risks and benefits of performing the procedure for the specified clinical scenario.

SOE: Strength of Evidence. The assessment of the amount and quality of evidence found in the peer reviewed medical literature for an appropriateness recommendation.

  • References: The citation number and PMID for the reference(s) associated with the recommendation.
  • Study Quality: The assessment of the quality of an individual reference based on the number of study quality elements described in the reference.

RRL: Relative Radiation Level. A population based assessment of the amount of radiation a typical patient may be exposed to during the specified procedure.

Rating: The final rating (1-9 scale) for the procedure as determined by the panel during rating rounds.

Median: The median rating (1-9 scale) for the procedure as determined by the panel during rating rounds.

Final tabulations: A histogram showing the number of panel members who rated the procedure as noted in the column heading (ie, 1, 2, 3, etc.).

Additional supporting documents about the AC methodology and processes can be found at www.acr.org/ac.