The effect of the imaging-based iterative reconstruction by SafeCT for demonstrating early CT sign in acute ischemic stroke patients

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15786
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: University of the Ryukyus
• Principal Investigator: Yogi Akira 琉球大学, 病院, 准教授 (80510718)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: early CT sign / 急性期脳梗塞 / CT / MRI / 拡散強調像 / 基底核の不明瞭化 / 皮髄境界の不明瞭化 / 脳溝の不明瞭化

Outline of Final Research Achievements

126, 60 and 26 cases with acute ischemic stroke, who underwent both head CT and DWI from three institutes, including Ryukyu University Hospital were retrospectively selected. We divided CT images into three groups: original group, consisting of original images with 0.625 mm slice thickness; 5mm group, consisting of reconstructed images with 5 mm slice thickness; and SafeCT group, consisting of denoised original images by SafeCT.
One radiologist has blindly evaluated for the extent of 43 acute brain infarct, based on the early CT sign. We compared the results with DWI as reference standard to determine the concordance of the extent of the infarction, categorizing into three rates: good, fair, and poor. We also measured the time for the interpretation. The concordance rates of each group were significantly different (Friedman test; p < 0.03). The interpretation time for SafeCT group was shorter than that of 5 mm and thin-slice group (p < 0.05 and <0.0001, respectively).

Free Research Field

神経放射線

Academic Significance and Societal Importance of the Research Achievements

本研究の目的は、SafeCTを用いたCT画像のノイズ除去によって、評価が難しいearly CT signの検出率が向上し、急性期脳梗塞の診断をより正確にできるかどうか検討することである。これまでearly CT signの評価は5mmスライス厚の画像で行われてきたが、本研究では初めて、評価に0.625mmスライスの元画像を用いている。元画像でもノイズ除去によって評価に有用であることが示されれば、部分容積現象による脳溝狭小化の見逃しも激減すると思われる。本研究の結果から、CTのみでも誰もが分かりやすく急性期脳梗塞を診断出来るようになり、急性期脳梗塞の診療に大きく貢献することが期待できる。