Imaging vital to localize stroke

By Eleanor McDermid

Clinical signs and symptoms can rarely distinguish posterior circulation infarction (PCI) from anterior circulation infarction (ACI), say researchers.

Ming Liu (Sichuan University, Chengdu, China) and team did find some symptoms that occurred only or mostly in PCI, but these were rare.

"These findings emphasize the fact that the clinical manifestations between PCI and ACI have a high degree of similarity," they write in Stroke.

They warn: "Inaccurate localization would be common if clinicians only relied on clinical symptoms/signs to differentiate PCI from ACI, and this observation suggests that neuroimaging findings, particularly [magnetic resonance imaging], are vital for accurate localization."

All 1174 patients in the current study had PCI or ACI confirmed on magnetic resonance imaging. The most common finding on chart review of the 302 PCI patients was nausea and vomiting, which occurred in 33.8% versus 10.4% of the 872 ACI patients. Ataxia was the next most common, in 31.5% versus 5.4%. The positive predictive values (PPVs) of these findings were 52.8% and 66.9%, respectively, and the sensitivities were only a little over 30%.

Other signs and symptoms appeared less frequently, ranging from 1.3% for quadrantanopia to 18.9% for vertigo.

Some findings were very specific for PCI; Horner's syndrome, crossed sensory deficits, quadrantanopia, and oculomotor nerve palsy all had a PPV of 100%, and crossed motor deficits had a PPV of 92.3%. However, these were very rare, with Horner's syndrome, in just 4.0% of patients, the most common.

"Contrary to current belief, our results do not support the conventional wisdom that holds that disturbed consciousness is highly specific for PCI," note Liu et al. Indeed, it appeared to be less common in PCI than ACI patients, at 10.3% versus 18.6%.

The most common symptoms overall were hemiplegia, which affected 53.6% of PCI and 74.9% of ACI patients, central facial/lingual palsy, found in 40.7% of PCI and 62.2% of ACI patients, and hemisensory deficits, in 36.4% and 34.2% of PCI and ACI patients, respectively. These all had low PPVs for PCI, with hemisensory deficits the most accurate, at 27.0%.

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