TC Crânio em doentes com AIT

Estudo que incide na análise de TC de Crânio a doentes com AIT de evolução inferior a 1 hora e mostra a não existência de alterações evidentes. Apresentado no 18th Meeting of the European Neurological Society (ENS).

Cranial Computer Tomography Unreliable in Depicting Underlying Cause in Transient Ischaemic Attacks Lasting Less Than 1 Hour: Presented at ENSBy Judith Moser, MD

NICE, France -- June 10, 2008 -- In the early phase after the onset of stroke-like neurological symptoms, cranial computer tomography (CCT) can neither depict nor rule out strokes in a reliable manner, according to the findings of a study presented here at the 18th Meeting of the European Neurological Society (ENS).

Transient ischaemic attacks (TIA) are defined as neurological symptoms lasting less than 24 hours without evidence of infarction. However, the risk for developing major strokes is increased in these patients and therefore necessitates immediate diagnostic work-up. Usually CCT is initially performed with the aim of ruling out other aetiologies such as haemorrhage, tumours, and major stroke.

"In order to justify exposure to radiation, the CCT should be sensitive enough to depict the underlying cause of symptoms," said principal investigator Stephan Ulmer, MD, Institute of Neuroradiology, University Hospital of Schleswig-Holstein, Kiel, Germany, in a poster presentation on June 9. "We assessed whether CCT scans are a sufficient imaging modality for monitoring TIA and whether the defined time window is applicable."

The researchers reviewed all CCT scans that were requested in patients with transient neurological symptoms at their clinics in a 1-year period. All studies that were requested for patients presenting with TIA were further analysed. Computed tomography scans (multirow-detector scanners), emergency notes, charts, and other performed imaging modalities such as magnetic resonance imaging were reviewed.

Patients that turned out to have experienced seizures with Todd paralysis rather than a TIA or other conditions that would require emergency imaging were excluded from the study.

Among 3,580 patients who underwent CCTs in the study period, 350 had been assessed due to transient neurological symptoms and were included in the study. 148 of these patients had experienced symptoms for less than 1 hour.

The researchers re-assessed the CCT images of this subgroup against the background of the final diagnoses. With initial CCT, 1 pathological finding was depicted in a case without ischaemia, whereas in 2 other cases the method failed to depict lesions which were definitely there. This resulted in a sensitivity of 50.0%, with specificity being 98.7%.

In contrast to the common recommendations, haemorrhage did not seem to be a matter of concern in this patient group. "There was not a single case of a haemorrhage when symptoms were confined to 1 hour," Dr. Ulmer emphasised. Only patients with symptoms beyond this time window were diagnosed with haemorrhagic strokes.

"We think that CCT is not a sufficient imaging method in patients whose symptoms resolve within 1 hour," Dr. Ulmer concluded. "Also, there might be a need to come up with a new definition of the TIA in terms of the defined time window."

He noted that these findings need to be confirmed on a larger scale, therefore a multicentre trial is being planned by the investigators.

[Presentation title: Is a Cranial Computer Tomography (CCT) Indicated in All Patients Suffering From Transient Ischemic Attack (TIA)? Abstract P350]

Link: Doctor's Guide - http://www.pslgroup.com/dg/223576.htm