A L Callen1, D S Chow2, Y A Chen3, H R Richelle4, J Pao4, M Bardis4, B D Weinberg5, C P Hess1, L P Sugrue6. 1. From the Neuroradiology Section (A.L.C., C.P.H., L.P.S.), Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California. 2. Neuroradiology Section (D.S.C., H.R.R., J.P., M.B.), Department of Radiology, University of California, Irvine, Irvine, California leo.sugrue@ucsf.edu. 3. Trillium Health Partners (Y.A.C.), University of Toronto, Toronto, Ontario, Canada. 4. Neuroradiology Section (D.S.C., H.R.R., J.P., M.B.), Department of Radiology, University of California, Irvine, Irvine, California. 5. Radiology and Imaging Sciences (B.D.W.), Emory University, Atlanta, Georgia. 6. From the Neuroradiology Section (A.L.C., C.P.H., L.P.S.), Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California leo.sugrue@ucsf.edu.
Abstract
BACKGROUND AND PURPOSE: Noncontrast head CTs are routinely acquired for patients with neurologic symptoms in the emergency department setting. Anecdotally, noncontrast head CTs performed in patients with prior negative findings with the same clinical indication are of low diagnostic yield. We hypothesized that the rate of acute findings in noncontrast head CTs performed in patients with a preceding study with negative findings would be lower compared with patients being imaged for the first time. MATERIALS AND METHODS: We retrospectively evaluated patients in the emergency department setting who underwent noncontrast head CTs at our institution during a 4-year period, recording whether the patient had undergone a prior noncontrast head CT, the clinical indication for the examination, and the examination outcome. Positive findings on examinations were defined as those that showed any intracranial abnormality that would necessitate a change in acute management, such as acute hemorrhage, hydrocephalus, herniation, or interval worsening of a prior finding. RESULTS: During the study period, 8160 patients in the emergency department setting underwent a total of 9593 noncontrast head CTs; 88.2% (7198/8160) had a single examination, and 11.8% (962/8160) had at least 1 repeat examination. The baseline positive rate of the "nonrepeat" group was 4.3% (308/7198). The 911 patients in the "repeat" group with negative findings on a baseline/first CT had a total of 1359 repeat noncontrast head CTs during the study period. The rate of positive findings for these repeat examinations was 1.8% (25/1359), significantly lower than the 4.3% baseline rate (P < .001). Of the repeat examinations that had positive findings, 80% (20/25) had a study indication that was discordant with that of the prior examination, compared with only 44% (593/1334) of the repeat examinations that had negative findings (P < .001). CONCLUSIONS: In a retrospective observational study based on approximately 10,000 examinations, we found that serial noncontrast head CT examinations in patients with prior negative findings with the same study indication are less likely to have positive findings compared with first-time examinations or examinations with a new indication. This finding suggests a negative predictive value of a prior noncontrast head CT examination with negative findings with the same clinical indication.
BACKGROUND AND PURPOSE: Noncontrast head CTs are routinely acquired for patients with neurologic symptoms in the emergency department setting. Anecdotally, noncontrast head CTs performed in patients with prior negative findings with the same clinical indication are of low diagnostic yield. We hypothesized that the rate of acute findings in noncontrast head CTs performed in patients with a preceding study with negative findings would be lower compared with patients being imaged for the first time. MATERIALS AND METHODS: We retrospectively evaluated patients in the emergency department setting who underwent noncontrast head CTs at our institution during a 4-year period, recording whether the patient had undergone a prior noncontrast head CT, the clinical indication for the examination, and the examination outcome. Positive findings on examinations were defined as those that showed any intracranial abnormality that would necessitate a change in acute management, such as acute hemorrhage, hydrocephalus, herniation, or interval worsening of a prior finding. RESULTS: During the study period, 8160 patients in the emergency department setting underwent a total of 9593 noncontrast head CTs; 88.2% (7198/8160) had a single examination, and 11.8% (962/8160) had at least 1 repeat examination. The baseline positive rate of the "nonrepeat" group was 4.3% (308/7198). The 911 patients in the "repeat" group with negative findings on a baseline/first CT had a total of 1359 repeat noncontrast head CTs during the study period. The rate of positive findings for these repeat examinations was 1.8% (25/1359), significantly lower than the 4.3% baseline rate (P < .001). Of the repeat examinations that had positive findings, 80% (20/25) had a study indication that was discordant with that of the prior examination, compared with only 44% (593/1334) of the repeat examinations that had negative findings (P < .001). CONCLUSIONS: In a retrospective observational study based on approximately 10,000 examinations, we found that serial noncontrast head CT examinations in patients with prior negative findings with the same study indication are less likely to have positive findings compared with first-time examinations or examinations with a new indication. This finding suggests a negative predictive value of a prior noncontrast head CT examination with negative findings with the same clinical indication.
Authors: Seema P Anandalwar; Christine Y Mau; Chirag G Gordhan; Neil Majmundar; Ahmed Meleis; Charles J Prestigiacomo; Ziad C Sifri Journal: J Neurosurg Date: 2016-01-15 Impact factor: 5.115
Authors: Ruth M Dunne; Ivan K Ip; Sarah Abbett; Esteban F Gershanik; Ali S Raja; Andetta Hunsaker; Ramin Khorasani Journal: Radiology Date: 2015-02-13 Impact factor: 11.105
Authors: Rebecca Smith-Bindman; Diana L Miglioretti; Eric Johnson; Choonsik Lee; Heather Spencer Feigelson; Michael Flynn; Robert T Greenlee; Randell L Kruger; Mark C Hornbrook; Douglas Roblin; Leif I Solberg; Nicholas Vanneman; Sheila Weinmann; Andrew E Williams Journal: JAMA Date: 2012-06-13 Impact factor: 56.272
Authors: Christopher L Sistrom; Pragya A Dang; Jeffrey B Weilburg; Keith J Dreyer; Daniel I Rosenthal; James H Thrall Journal: Radiology Date: 2009-02-12 Impact factor: 11.105