Dr. James R. Brorson, associate professor of neurology at the University of Chicago Medicine, told Reuters Health by email, “Through a carefully performed meta-analysis, this study underscores the growing evidence for the very high sensitivity of plain head CT scanning for acute subarachnoid hemorrhage (within six hours of onset).”

“By assembling several previously published studies in a systematic review, the authors rather starkly present data that suggest that the current standard practice of requiring lumbar puncture after negative CT when SAH is suspected may no longer be necessary,” he said.

Dr. Brorson suggested that doctors may begin to omit lumbar puncture after negative CT in selected cases.

“It has been thought that small ‘sentinel’ bleeds, or bleeding in patients with low hematocrit, may sometimes produce false-negative CT scans. It would be interesting to know whether patient-specific factors like these might still sometimes consistently produce false-negative scans,” he added.

Dr. Brorson, who was not involved in the study, cautioned that “a danger in emphasizing these results might be if they are extrapolated by practitioners to patients outside the six-hour time window covered in this study, possibly leading to missed cases of subarachnoid hemorrhage first presenting for scanning at later times after the ictus.”

Regarding further study, Dr. Dubosh would like to explore the sensitivity of a noncontrast head CT beyond six hours.

The authors reported no funding or disclosures.