Background: Although left ventricular (LV) quantification software for transthoracic three-dimensional echocardiography (3DE) have been steadily advancing, the measurement accuracy of semiautomated and fully automated software has not been systematically investigated. Methods:We performed a systematic review and metaanalysis following a search of the PubMed, Embase, and Scopus databases for studies that directly compared LV volumes and ejection fraction (EF) using 3DE with either semiautomated or fully automated software and cardiac magnetic resonance (CMR) during the period from January, 2011, to July, 2018.A random effects model was used to determine the bias and 95% CI of LV end-diastolic volume (EDV), end-systolic volume (ESV), and EF.A meta-regression and subgroup analysis were performed to investigate inter-software variabilities.Results: Of a total of 38 studies, the pooled bias and 95% CI for EDV, ESV, and EF of semiautomated software were -39.3 mL (-49.2 to -29.5 mL), -19.6 mL (-25.9 to -13.3 mL), and -0.6% (-2.0% to 0.7%), respectively.The corresponding values for fully automated software were -14.5 mL (-25.7 to -3.3 mL), -6.3 mL (-11.4 to -1.2 mL), and -1.1% (-3.5% to 1.3%).The EDV and ESV biases became significantly smaller and less heterogeneous when fully automated software was used.A meta-regression analysis revealed that EDV bias became larger with an increase in EDV when semiautomated software was used but not when fully automated software was used.Conclusions: Although 3DE still underestimates LV volumes, EF showed similar values to CMR for both types of software.The adoption of fully automated software could further improve measurement accuracy with fewer observer variabilities.

54歳女性．2014年1月よりRaynaud症状が出現．2月に手指の腫脹，4月には下腿浮腫，乾性咳嗽と労作時呼吸苦が出現したため，精査治療目的に当科入院となった．入院時の精査では心膜炎・胸膜炎に加えて間質性肺炎および肺高血圧症の合併を認めた．強皮症が疑われたが手指腫脹のみで皮膚硬化は明らかでなく，抗Scl-70抗体，抗セントロメア抗体，抗RNP抗体はすべて陰性で確定診断には至らなかった．鑑別のため爪郭ビデオ顕微鏡（Nailfold Videocapillaroscopy: NVC）検査を施行したところ，Giant capillaryやHemorrhagesといった強皮症に特徴的な爪郭毛細血管異常を認め，NVCスコアリングで強皮症の早期パターンに矛盾しない結果であった．この結果に基づき皮膚生検を施行したところ，真皮から皮下組織にかけて膠原線維の増生と付属器に沿った線維化の進展を認め強皮症と診断できた．重要臓器障害を伴う強皮症に対してステロイド大量療法およびシクロフォスファミド静注療法を開始し以後良好な経過をたどっている． 2013年ACR/EULARによって新強皮症分類基準が発表され，皮膚硬化を認めなくても早期に強皮症と診断可能となった．本症例でも同基準を用いると手指腫脹，爪郭毛細血管異常，間質性肺炎／肺高血圧症，Raynaud症状でスコアを満たし強皮症の診断に至る．本邦ではNVCが導入されておらずその基準のバリデーションは行われていないが，NVCは強皮症の早期診断に有用であると考えられた．