Perfusion CT in Acute Ischemic Stroke: A Qualitative and Quantitative Comparison of Deconvolution and Maximum Slope Approach

Abstract

BACKGROUND AND PURPOSE:PCT postprocessing commonly uses either the MS or a variant of the DC approach for modeling of voxel-based time-attenuation curves. There is an ongoing discussion about the respective merits and limitations of both methods, frequently on the basis of theoretic reasoning or simulated data. We performed a qualitative and quantitative comparison of DC and MS by using identical source datasets and preprocessing parameters.

Multivariate Dynamic Prediction of Ischemic Infarction and Tissue Salvage as a Function of Time and Degree of Recanalization

“…28 In temporal parameter maps (MTT and TTD) brain voxel with very low CBV and undetectable attenuation levels of bolus arrival could not be assigned a discrete time value exhibiting a theoretical indefinite delay. However, these voxels are likely characterizing tissue with high infarct probability as they are preferably located within the core lesion.…”

“…Perfusion parameter maps were calculated based on a deconvolution model by least mean squares fitting. 28 Voxelwise parenchymal time attenuation curves were deconvolved with a mean arterial input function measured in early arterialized voxels of the middle and anterior cerebral artery of the nonischemic side (on the level where arterial branches cross the plane perpendicular); venous outflow and reference for maximum enhancement was measured in the superior sagittal sinus. Voxels of arterial and venous reference vessels were detected automatically with supervision.…”

Perfusion Deficits and Mismatch in Patients with Acute Lacunar Infarcts Studied with Whole-Brain CT Perfusion

“…25 Condensing both pathologic changes in contrast bolus delay time from arterial enhancement to tissue enhancement and tissue transit time, TTD describes the time of contrast medium washout and is very sensitive to all kinds of hemodynamic disturbances. 26 It has been argued that patients with true LIs should not have detectable perfusion deficits and/or that they should have no mismatch between infarcted tissue and hypoperfused tissue. 12 This study suggests that the hemodynamic abnormalities of LIs, though small, are very similar to those described in infarcts resulting from occlusion of greater vessels (it has been claimed that lacunes are just small strokes).…”

Pilot study of combined FDG‐PET and dynamic contrast‐enhanced CT of locally advanced cervical carcinoma before and during concurrent chemoradiotherapy suggests association between changes in tumor blood volume and treatment response

“…Analysis of each scan consisted of the following sequence: registering the images with respect to a midphase frame to correct for anatomical motion; specifying the precontrast baseline using the first frame; applying 4D noise reduction; segmenting out tissues with voxels outside the range [−50, 150] HU; selecting the femoral artery (at the same level as the tumor) to serve as the contrast reference vessel; and specifying an “Outside Relative Threshold” of 50% to exclude as vessels any voxels having an HU value above 50% of the selected reference vessel. The software then applied a deconvolution model18 to obtain volumetric maps of BF, BV, and permeability for the entire imaged volume. Semi‐independent DCE‐CT analyses were carried out by a medical physicist and a radiation oncologist who was trained by a body imaging radiologist experienced in perfusion CT analysis.…”