論文

Objectives: To investigate the association of lung signal intensity changes during forced breathing using dynamic digital radiography (DDR) with pulmonary function and disease severity in patients with chronic obstructive pulmonary disease (COPD). Methods: This retrospective study included 46 healthy subjects and 33 COPD patients who underwent posteroanterior chest DDR examination. We collected raw signal intensity and gray-scale image data. The lung contour was extracted on the gray-scale images using our previously developed automated lung field tracking system and calculated the average of signal intensity values within the extracted lung contour on gray-scale images. Lung signal intensity changes were quantified as SImax/SImin, representing the maximum ratio of the average signal intensity in the inspiratory phase to that in the expiratory phase. We investigated the correlation between SImax/SImin and pulmonary function parameters, and differences in SImax/SImin by disease severity. Results: SImax/SImin showed the highest correlation with VC (rs = 0.54, P < 0.0001), followed by FEV1 (rs = 0.44, P < 0.0001), both of which are key indicators of COPD pathophysiology. In a multivariate linear regression analysis adjusted for confounding factors, SImax/SImin was significantly lower in the severe COPD group compared to the normal group (P = 0.0004) and mild COPD group (P=0.0022), suggesting its potential usefulness in assessing COPD severity. Conclusion: This study suggests that the signal intensity changes of lung fields during forced breathing using DDR reflect the pathophysiology of COPD and can be a useful index in assessing pulmonary function in COPD patients, potentially improving COPD diagnosis and management.

Background: Chronic obstructive pulmonary disease (COPD) is frequently associated with cachexia, leading to poor prognoses and reduced quality of life. However, the mechanisms underlying adipose tissue atrophy, its pathological significance and its interaction with skeletal muscle remain poorly understood. We hypothesised that adipose tissue atrophy precedes muscle wasting in COPD-associated cachexia, and muscle atrophy progresses through adipose–muscle crosstalk. Methods: We analysed chest computed tomography scans of 185 patients with COPD to quantify the cross-sectional areas of the pectoralis muscle (PM), subcutaneous adipose tissue (SAT) and epicardial adipose tissue (EAT), and the percentage of low attenuation area (LAA%) as an index of emphysema. To elucidate the pathophysiological mechanisms underlying cachexia in COPD, we performed histological and molecular analyses of the lung, muscle and adipose tissues over time in a cigarette smoke–induced emphysema mouse model. Further, we used an in vitro culture system of differentiated adipocytes (3T3-L1) and myotubes (C2C12) to study the effects of cigarette smoke extract (CSE) on adipose–muscle interaction. Results: In patients with COPD, the areas of PM, SAT and EAT all demonstrated significant negative correlations with LAA%; notably, PM and EAT were independently associated with the extent of emphysematous changes. In the smoke-exposed murine model, adipose tissue atrophy was observed after 1 month of exposure, accompanied by increased expressions of IL-6 and IL-1β, macrophage infiltration and the upregulation of the lipolytic enzymes ATGL and HSL. The adipose atrophy had further progressed after 3 months of exposure, and the high expression of UCP1 was sustained, which suggested the browning of adipose tissue. Conversely, muscle atrophy was not evident at 1 month but became apparent after 3 months, coinciding with emphysema development. This was associated with the downregulation of the myogenic markers MyoD and Myogenin and the upregulation of the muscle degradation marker Atrogin-1. In vitro experiments revealed that CSE exposure reduced lipid droplet content and induced IL-6 and IL-1β expressions in adipocytes. Conditioned media from CSE-treated adipocytes triggered myotube atrophy and downregulated MyoD and Myogenin but upregulated Atrogin-1. Conclusions: Our findings indicate that cigarette smoke-induced adipose tissue atrophy precedes muscle wasting, and alterations in adipose tissue may contribute to muscle atrophy progression. Adipose tissue dysfunction may be implicated in the development of cachexia in patients with COPD, highlighting its potential as a therapeutic target.

症例は40歳代女性で、胸痛を主訴に近医を受診し、胸部単純X線で左気胸を指摘され当院へ紹介入院となった。胸部単純CTにて左気胸を認めた。両肺底部に複数の不整な嚢胞、両下葉に浸潤影、小葉中心性陰影および気管支拡張を認めた。なお、約1年前の肺炎時のCTでは嚢胞は認められなかった。胸腔ドレーンを留置するも気胸およびリークの改善を認めなかったため、胸腔鏡下左肺下葉嚢胞切除術を施行した。術後経過は良好で、術後約1週間で退院した。比較的若年者に繰り返す肺炎後に不整な嚢胞が散見され、難治性の気胸を発症したことから肺組織の脆弱性が示唆され、基礎疾患としてEhlers-Danlos症候群の可能性が疑われた。遺伝子検査ではCOL5A2遺伝子変異が陽性(ミスセンス変異)であり、古典型Ehlers-Danlos症候群と診断された。また、COL3A1遺伝子変異は陰性であったことから、血管型Ehlers-Danlos症候群は否定された。

【目的】(1)立位CTの物理特性の評価,(2)大血管と骨盤底への重力の影響を評価すること.【方法】ファントムを用いて立位CTと臥位CT,それぞれの物理特性の評価を行った.健常人ボランティアを対象に立位CTと臥位CTを同日に施行,大静脈と大動脈の面積と骨盤底の変化を評価した.【結果】立位CTと臥位CT両者の物理特性に有意差は見られなかった.仰臥位と比較して直立位では,上大静脈の面積は有意に小さく,横隔膜の高さでの下大静脈の面積に有意差は見られず,下大静脈下端部での面積は有意に大きくなった.一方,大動脈の面積に関しては姿勢による有意差は見られなかった.骨盤底は直立位で下降した.【結論】立位CTと臥位CTの性能はほぼ同等であり,立位CTは,人体に対する重力の影響を評価するのに有用であった.(著者抄録)

dual energy CTとは、管電圧の異なる2種類のX線で撮影する技術である。近年、CTメーカー各社が独自のdual energy CTの技術開発を進めており、臨床現場での認知・普及も進みつつある。CT画像は、被写体のX線減弱の情報を、水を基準としたCT値として可視化するものであるが、通常のCTでは多色エネルギーのX線を使用しているため、X線が被写体を通過する過程で低エネルギーの成分が吸収され、高エネルギーの成分が残る「ビームハードニング効果」が起こり、アーチファクトの原因となる。また、「線減弱係数」は「質量減弱係数」×「密度」で表され、「質量減弱係数」は本来物質固有の数値だが、撮影対象の密度状態によって、異なる物質のCT値が同じになる場合がある。X線エネルギーによるCT値の変化は物質に固有であることから、2種類の管電圧でCTを撮影することで、物質弁別(material decomposition)を行うことが可能となる(図1)。また、2種類のX線のデータを処理することで、さまざまなエネルギーの単色X線画像を仮想的に合成することが可能である。これにより、前述のビームハードニング効果を減弱させることができる。そのほか、dual energy CT撮影で得られる画像情報に、仮想単純画像、実効原子番号画像、電子密度画像などがある。本稿では、dual energy CTの解析方法、撮影法、原理と取得できる画像について解説する。(著者抄録)

© 2016, Japanese Circulation Society. All rights reserved. Background: Controlling and decreasing the heart rate (HR) of patients during coronary computed tomography angiography (CCTA) is necessary to reduce radiation exposure and improve image quality. This prospective multicenter study aimed to investigate whether HR control with landiolol hydrochloride is useful for reducing radiation exposure during CCTA. Methods and Results: We investigated 219 patients with suspected ischemic heart disease whose pretest HRs were 50–80 beats/min. We measured the HR before and after administration of landiolol hydrochloride and compared the estimated exposure inferred from the HR before administration of landiolol hydrochloride with the actual dose. After administration of landiolol hydrochloride, the mean HR (59.9 ± 6.4 beats/min) at the time of CCTA was significantly lower than before administration (69.3 ± 7.3 beats/min; P<0.001); 80% of the patients had controlled HRs at ≤65 beats/min. HR and blood pressure of all the patients recovered after the scan. The mean radiation dose in all patients was approximately 50% derived from the inferred dose before use of landiolol hydrochloride (4.5 ± 3.2 vs. 9.0 ± 3.7 mSv; P<0.001). There were no adverse events during this study. Conclusions: The use of landiolol hydrochloride during CCTA was safe and resulted in approximately 50% decrease in radiation exposure dose, suggesting the clinical usefulness of this drug.

© 2020 Hong Kong Academy of Medicine Press. All rights reserved. Radiologists are often unfamiliar with anorectal malformations and have limited knowledge of the surgical procedures for their repair. In this article, we provide a comprehensible description of the surgical procedures for radiologists, review previous literature, and summarise the incidence of the complications. Moreover, we detail major postoperative complications consequent to the use of various imaging techniques, including anorectal prolapse, anal stenosis, urethral injury, posterior urethral diverticulum, neurogenic bladder, adhesion of reconstructed vagina, leakage from suture lines, and trocar site hernia. Knowledge of these complications and surgical procedures is important to radiologists for diagnosis and determination of a treatment strategy.