TY - JOUR
T1 - Computed tomographic angiography for detecting cerebral aneurysms
T2 - Implications of aneurysm size distribution for the sensitivity, specificity, and likelihood ratios
AU - Van Gelder, James M.
AU - Hoh, Brian L.
AU - Ogilvy, Christopher S.
AU - Solomon, Robert A.
AU - Batjer, H. Hunt
PY - 2003/9/1
Y1 - 2003/9/1
N2 - OBJECTIVE: This study examined the efficacy of computed tomographic angiography (CTA) for detection of ruptured and unruptured aneurysms after adjustment for their size distributions under various conditions of aneurysm prevalence. METHODS: A systematic review was used to estimate 1) the aneurysm size-specific sensitivity and specificity of CTA, and 2) the size distributions of ruptured and unruptured aneurysms. Probabilistic computer simulation was used to estimate the efficacy of CTA in the detection of aneurysms. RESULTS. The sensitivity of CTA ranged from 53% (95% confidence interval [CI], 44-62%) for 2-mm aneurysms to 95% (95% CI, 92-97%) for 7-mm aneurysms. The overall specificity was 98.9% (95% CI, 91.5-99.99%), but there was between-study heterogeneity. The estimated negative likelihood ratios for ruptured, unruptured, and at least 6-mm unruptured aneurysms were 0.081, 0.18, and 0.012, respectively. The positive likelihood ratio for CTA was sensitive to the pretest probability, the size of the positive finding, and the clinical context. With a small pretest probability, the positive likelihood ratio for unruptured aneurysms ranged from 15 for 2-mm aneurysms to 61 for 5-mm aneurysms. The positive likelihood ratio for ruptured aneurysms with an intermediate pretest probability (50%) ranged from 3.9 to 56 for 2- to 5-mm aneurysms. CONCLUSION: Small aneurysms detected on CTA should be investigated further unless there is a high pretest probability of a ruptured aneurysm. During screening for ruptured aneurysms, a negative CTA should be investigated further. During screening for unruptured aneurysms, a negative CTA results in a very low probability of a clinically important aneurysm.
AB - OBJECTIVE: This study examined the efficacy of computed tomographic angiography (CTA) for detection of ruptured and unruptured aneurysms after adjustment for their size distributions under various conditions of aneurysm prevalence. METHODS: A systematic review was used to estimate 1) the aneurysm size-specific sensitivity and specificity of CTA, and 2) the size distributions of ruptured and unruptured aneurysms. Probabilistic computer simulation was used to estimate the efficacy of CTA in the detection of aneurysms. RESULTS. The sensitivity of CTA ranged from 53% (95% confidence interval [CI], 44-62%) for 2-mm aneurysms to 95% (95% CI, 92-97%) for 7-mm aneurysms. The overall specificity was 98.9% (95% CI, 91.5-99.99%), but there was between-study heterogeneity. The estimated negative likelihood ratios for ruptured, unruptured, and at least 6-mm unruptured aneurysms were 0.081, 0.18, and 0.012, respectively. The positive likelihood ratio for CTA was sensitive to the pretest probability, the size of the positive finding, and the clinical context. With a small pretest probability, the positive likelihood ratio for unruptured aneurysms ranged from 15 for 2-mm aneurysms to 61 for 5-mm aneurysms. The positive likelihood ratio for ruptured aneurysms with an intermediate pretest probability (50%) ranged from 3.9 to 56 for 2- to 5-mm aneurysms. CONCLUSION: Small aneurysms detected on CTA should be investigated further unless there is a high pretest probability of a ruptured aneurysm. During screening for ruptured aneurysms, a negative CTA should be investigated further. During screening for unruptured aneurysms, a negative CTA results in a very low probability of a clinically important aneurysm.
KW - Cerebral aneurysm
KW - Computed tomographic angiography
KW - Computer simulation
KW - Probabilistic sensitivity analysis
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U2 - 10.1227/01.NEU.0000080060.97293.EE
DO - 10.1227/01.NEU.0000080060.97293.EE
M3 - Review article
C2 - 12943576
AN - SCOPUS:0042355550
SN - 0148-396X
VL - 53
SP - 597
EP - 606
JO - Neurosurgery
JF - Neurosurgery
IS - 3
ER -