ABSTRACT
OBJECT: Cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH) implies high risk for secondary ischemia. It requires early diagnosis to start treatment on time. We aimed to assess the utility of "whole brain" VPCT for detecting localization and characteristics of arterial vasospasm. METHODS: 23 patients received a non-enhanced CT, VPCT and CTA of the brain. The distribution of ischemic lesions was analyzed on 3D-perfusion-parameter-maps of CBF, CBV, MTT, TTS, TTP, and TTD. CT-angiographic axial and coronal maximum-intensity-projections were reconstructed to determine arterial vasospasm. CT-data was compared to DSA, if performed additionally. Volume-of-interest placement was used to obtain quantitative mean VPCT values. RESULTS: 82% patients (n=19) had focal cerebral hypoperfusion. 100% sensitivity and 100% specificity was found for TTS (median 1.9s), MTT (median 5.9s) and TTD (median 7.6s). CBV showed no significant differences. In 78% (n=18) focal vessel aberrations could be detected either on CTA or DSA or on both. CONCLUSION: VPCT is a non-invasive method with the ability to detect focal perfusion deficits almost in the whole brain. While DSA remains to be the gold standard for detection of CV, VPCT has the potential to improve noninvasive diagnosis and treatment decisions.
Subject(s)
Cerebral Angiography/methods , Imaging, Three-Dimensional , Subarachnoid Hemorrhage/diagnostic imaging , Tomography, X-Ray Computed/methods , Vasospasm, Intracranial/diagnostic imaging , Adult , Aged , Aged, 80 and over , Contrast Media , Diagnosis, Differential , Female , Humans , Iopamidol/analogs & derivatives , Male , Middle Aged , Radiographic Image Interpretation, Computer-Assisted , Sensitivity and Specificity , Subarachnoid Hemorrhage/complications , Vasospasm, Intracranial/etiologyABSTRACT
A new noninvasive technique that reveals cross sectional images of scattering media is presented. It is based on a continuous wave frequency modulated radar, but uses a tunable laser in the near infrared. As the full width at half maximum resolution of 16 µm is demonstrated with an external cavity laser, the chirp optical coherence tomography becomes an alternative to conventional short coherence tomography with the advantage of a simplified optical setup. The analysis of two-layer solid phantoms shows that the backscattered light gets stronger with decreasing anisotropic factor and increasing scattering coefficient, as predicted by Monte Carlo simulations. By introducing a two-phase chirp sequence, the combination of lateral resolved perfusion and depth resolved structure is shown. © 1998 Society of Photo-Optical Instrumentation Engineers.
