Latest generation of flat detector CT as a peri-interventional diagnostic tool: a comparative study with multidetector CT

Abstract

Background and purpose: Flat detector CT (FDCT) has been used as a peri-interventional diagnostic tool in numerous studies with mixed results regarding image quality and detection of intracranial lesions. We compared the diagnostic aspects of the latest generation FDCT with standard multidetector CT (MDCT).

Materials and methods: 102 patients were included in our retrospective study. All patients had undergone interventional procedures. FDCT was acquired peri-interventionally and compared with postinterventional MDCT regarding depiction of ventricular/subarachnoidal spaces, detection of intracranial hemorrhage, and delineation of ischemic lesions using an ordinal scale. Ischemic lesions were quantified with the Alberta Stroke Program Early CT Scale (ASPECTS) on both examinations. Two neuroradiologists with varying grades of experience and a medical student scored the anonymized images separately, blinded to the clinical history.

Results: The two methods were of equal diagnostic value regarding evaluation of the ventricular system and the subarachnoidal spaces. Subarachnoidal, intraventricular, and parenchymal hemorrhages were detected with a sensitivity of 95%, 97%, and 100% and specificity of 97%, 100%, and 99%, respectively, using FDCT. Gray-white differentiation was feasible in the majority of FDCT scans, and ischemic lesions were detected with a sensitivity of 71% on FDCT, compared with MDCT scans. The mean difference in ASPECTS values on FDCT and MDCT was 0.5 points (95% CI 0.12 to 0.88).

Conclusions: The latest generation of FDCT is a reliable and accurate tool for the detection of intracranial hemorrhage. Gray-white differentiation is feasible in the supratentorial region.

Keywords: Angiography; CT; Hemorrhage; Stroke.

Figure 1

(A, B) CT images after balloon assisted coil embolization of an anterior communicating artery aneurysm. (A) Flat detector CT (FDCT) shows a cortical hyperattenuation of the right frontal lobe (black arrowhead). A subarachnoidal hemorrhage (SAH) can be excluded on both FDCT (A) and follow-up multidetector CT (MDCT) (B) images. Gray–white matter differentiation as well as exclusion of postinterventional ischemic lesions is feasible in both examinations. (C, D) Right temporal SAH. Blood is delineated on both FDCT (C) and MDCT (D) examinations (black arrows). Gray–white matter differentiation of the cerebellum is limited on FDCT (C) but the fourth ventricle is clearly depicted and an intraventricular hemorrhage can be excluded.

Figure 2

(A) An older small cortical infarction is depicted on the flat detector CT (FDCT) scan after carotid artery stenting (A, black arrow). No acute ischemic lesions were detected on this scan. The same lesion can be confirmed on multidetector CT (MDCT) (B, black arrow). (C, D) CT images prior to thrombectomy and at follow-up. Acute ischemic lesions can be seen on non-contrast FDCT (C, black arrowheads) performed prior to thrombectomy. An intracranial hemorrhage can be excluded and an Alberta Stroke Program early CT Scale (ASPECTS) score of 7 can be rated on FDCT images. Ischemic lesions are confirmed on follow-up MDCT images (D, black arrowheads) after rapid reperfusion.

Figure 3

A parenchymal hemorrhage and subarachnoidal hemorrhage (SAH) can be diagnosed on flat detector CT (FDCT) (A) and verified on follow-up multidetector CT (MDCT) (B). (C, D) A small SAH can be seen in the prepontine cistern on FDCT (C, black arrow) images. The same findings were delineated on follow-up MDCT (D, black arrow).