Online ISSN: 2187-2988 Print ISSN: 0911-1794
特定非営利活動法人日本小児循環器学会 Japanese Society of Pediatric Cardiology and Cardiac Surgery
Pediatric Cardiology and Cardiac Surgery 38(3): 189-195 (2022)

症例報告Case Report

多孔性筋性部心室中隔欠損症における心臓MRI二次元位相差コントラスト法を用いた心室中隔en face画像の有用性僧帽弁狭窄を合併した幼児例の考察En Face Imaging of the Ventricular Septum by Cardiac Two-Dimensional Phase-Contrast Magnetic Resonance Imaging for Evaluating Multiple Ventricular Septal Defects: A Case Report of a 1-Year-Old Patient with Mitral Stenosis

1あかね会土谷総合病院 小児科Department of Pediatrics, Tsuchiya General Hospital ◇ Hiroshima, Japan

2あかね会土谷総合病院 放射線科Department of Radiology, Tsuchiya General Hospital ◇ Hiroshima, Japan

3あかね会土谷総合病院 心臓血管外科Department of Cardiovascular Surgery, Tsuchiya General Hospital ◇ Hiroshima, Japan

受付日:2022年1月13日Received: January 13, 2022
受理日:2022年7月10日Accepted: July 10, 2022
発行日:2022年8月1日Published: August 1, 2022

心室中隔欠損症(VSD)のうち,筋性部の肉柱部中隔に存在するものは多孔性であることが多く,心臓超音波検査による形態や短絡量の評価は困難なことがある.一方,心臓MRI位相差コントラスト法(Phase Contrast:PC法)は,任意の断面において直行する血流を撮像できる.今回,perimembranous VSD(pmVSD)と多孔性のmuscular VSD(mVSD)に僧帽弁上狭窄輪(supra mitral ring: SMR)を合併した1歳の症例にPC法を用いてVSD en face画像を撮像し,複数あるVSDの位置を描出し,欠損孔毎の短絡量を計測した.肺体血流比(Qp/Qs)2.05,短絡血流の内訳は,pmVSD 76.4%,mVSDのうち右室流出路(RVOT)近傍の最も大きな欠損孔は13.4%であった.SMRの解除,pmVSDの閉鎖に加え,RVOTからアプローチし,mVSDの最大孔とその近傍の孔を閉鎖した.術後,遺残短絡は少量で,PC法でQp/Qsは1.05であった.mVSDに対するPC法を用いたen face画像は孔の位置の同定や短絡量の推定に有用で,術前評価の一助となりうる.

Echocardiographic evaluation of the morphology and blood flow of multiple muscular ventricular septal defects (VSDs) can be difficult. Cardiac phase-contrast magnetic resonance imaging (PC-MRI) visualizes blood flow at any cross-section. We used phase-contrast imaging to visualize multiple muscular VSDs (mVSDs) and perimembranous VSD (pmVSDs) using en face imaging in a 1-year-old boy complicated with mitral stenosis (MS). Multiple VSDs were identified, and blood flow through each defect was evaluated. The pulmonary-to-systemic flow ratio (Qp/Qs) was 2.05. The breakdown of shunt flow was 76.4% for the pmVSD and 13.4% for the largest mVSD near the right ventricular outflow tract (RVOT). During surgery, we released the MS and closed the pmVSD. Then, we approached the RVOT and closed the largest mVSD and the nearby minor defect. A slight residual shunt was found postoperatively, and the Qp/Qs was 1.05. En face imaging with cardiac PC-MRI for multiple VSDs helps identify the foramen’s location and estimate the shunt volume, thus assisting in preoperative evaluation.

Key words: multiple ventricular septal defects; supramitral ring; cardiovascular magnetic resonance; en face imaging; two-dimensional phase-contrast imaging

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