Advantages of extended brain perfusion computed tomography: 9.6 cm coverage with time resolved computed...

Recent technical developments have led to an extension of perfusion computed tomography (PCT) scan range to cover nearly the entire brain and to reconstruct time resolved (4d) CT-angiography (CTA) datasets from the PCT data. The purpose of this study was to compare the results of simulated standard PCT and extended PCT with 4d-CTA.

Extended multimodal stroke CT (unenhanced cranial CT, CTA, and PCT) was acquired in 72 patients. PCT images with a scan coverage of 9.6 cm in the z-axis, simulated 2 cm PCT images at the level of the basal ganglia comparable to standard PCT, standard supra-aortic CTA, and 4d-CTA images were reconstructed. Two readers assessed the PCT image quality as well as pathologic findings in extended and simulated PCT, CTA, and 4d-CTA. The brain was divided into 4 axial segments. The independent samples t test was applied to test differences between data for significance.

In 75.0% of all patient exams, pathologic findings were observed in the PCT; these were located in 138 brain segments. In 24.1% of all 54 exams with pathologic PCT findings, the pathology would have been missed on standard PCT. The longer scan coverage resulted in a different final diagnosis in 34.7% of all exams. Quality of the PCT parameter maps was on average very good both for the supratentoric and the infratentoric brain areas (4.28 and 4.18, respectively, on a 5-point scale). In 90% of all exams with pathologic changes in the CTA, these abnormalities were also noted on 4d-CTA. In only 2.8% of all cases, the additional time resolution of the 4d-CTA provided additional information.

Extending the scan coverage of PCT from 2 cm to 9.6 cm led to an augmentation of clinically important information in the imaging of acute stroke.