論文

Saphenous veins (SVs) are frequently employed as bypass grafts. The SV graft failure is predominantly seen at the valve site. Avoiding valves during vein harvest would help reduce graft failure. We endeavored to detect SV valves, tributaries, and vessel size employing upright computed tomography (CT) for the raw cadaver venous samples and in healthy volunteers. Five cadaver legs were scanned. Anatomical analysis showed 3.0 (IQR: 2.0–3.0) valves and 13.50 (IQR: 10.00–16.25) tributaries. The upright CT completely detected, compared to 2.0 (IQR: 1.5–2.5, p = 0.06) valves and 9.5 (IQR: 7.5–13.0, p = 0.13) tributaries by supine CT. From a total of 190 volunteers, 138 (men:75, women:63) were included. The number of valves from the SF junction to 35 cm were significantly higher in upright CT than in supine CT bilaterally [upright vs. supine, Right: 4 (IQR: 3–5) vs. 2 (IQR:1–2), p < 0.0001, Left: 4 (IQR: 3–5) vs. 2 (IQR: 1–2), p < 0.0001]. The number of tributaries and vessel areas per leg were also higher for upright compared with supine CT. Upright CT enables non-invasive detection of SV valves, tributaries, and vessel size. Although not tested here, it is expected that upright CT may potentially improve graft assessment for bypass surgery.

Objective Data on statin for patients with aortic stenosis (AS) who underwent transcatheter aortic valve implantation (TAVI) are limited. The present study aimed to evaluate the impact of statin on midterm mortality of TAVI patients. Design Observational study. Setting This study included patients with AS from a Japanese multicentre registry who underwent TAVI. Participants The overall cohort included 2588 patients (84.4±5.2 years); majority were women (69.3%). The Society of Thoracic Surgeons risk score was 6.55% (IQR 4.55%-9.50%), the Euro II score was 3.74% (IQR 2.34%-6.02%) and the Clinical Frailty Scale score was 3.9±1.2. Interventions We classified patients based on statin at admission and identified 936 matched pairs after propensity score matching. Primary and secondary outcome measures The outcomes were all-cause and cardiovascular mortality. Results The median follow-up was 660 days. Statin at admission was associated with a significant reduction in all-cause mortality (adjusted HR (aHR) 0.76, 95% CI 0.58 to 0.99, p=0.04) and cardiovascular mortality (aHR 0.64, 95% CI 0.42 to 0.97, p=0.04). In the octogenarians, statin was associated with significantly lower all-cause mortality (aHR 0.87, 95% CI 0.75 to 0.99, p=0.04); however, the impact in the nonagenarians appeared to be lower (aHR 0.84, 95% CI 0.62 to 1.13, p=0.25). Comparing four groups according to previous coronary artery disease (CAD) and statin, there was a significant difference in all-cause mortality, and patients who did not receive statin despite previous CAD showed the worst prognosis (aHR 1.33, 95% CI 1.12 to 1.57 (patients who received statin without previous CAD as a reference), p<0.01). Conclusions Statin for TAVI patients will be beneficial even in octogenarians, but the benefits may disappear in nonagenarians. In addition, statin will be essential for TAVI patients with CAD. Further research is warranted to confirm and generalise our findings since this study has the inherent limitations of an observational study and included only Japanese patients.

Purpose: Bi-parametric magnetic resonance imaging (bpMRI) with diffusion-weighted images has wide utility in diagnosing clinically significant prostate cancer (csPCa). However, bpMRI yields more false-negatives for PI-RADS category 3 lesions than multiparametric (mp)MRI with dynamic-contrast-enhanced (DCE)-MRI. We investigated the utility of synthetic MRI with relaxometry maps for bpMRI-based diagnosis of csPCa. Methods: One hundred and five treatment-naïve patients who underwent mpMRI and synthetic MRI before prostate biopsy for suspected PCa between August 2019 and December 2020 were prospectively included. Three experts and three basic prostate radiologists evaluated the diagnostic performance of conventional bpMRI and synthetic bpMRI for csPCa. PI-RADS version 2.1 category 3 lesions were identified by consensus, and relaxometry measurements (T1-value, T2-value, and proton density [PD]) were performed. The diagnostic performance of relaxometry measurements for PI-RADS category 3 lesions in peripheral zone was compared with that of DCE-MRI. Histopathological evaluation results were used as the reference standard. Statistical analysis was performed using the areas under the receiver operating characteristic curve (AUC) and McNemar test. Results: In 102 patients without significant MRI artefacts, the diagnostic performance of conventional bpMRI was not significantly different from that of synthetic bpMRI for all readers (p = 0.11–0.79). The AUCs of the combination of T1-value, T2-value, and PD (T1 + T2 + PD) for csPCa in peripheral zone for PI-RADS category 3 lesions were 0.85 for expert and 0.86 for basic radiologists, with no significant difference between T1 + T2 + PD and DCE-MRI for both expert and basic radiologists (p = 0.29–0.45). Conclusion: Synthetic MRI with relaxometry maps shows promise for contrast media-free evaluation of csPCa.

Purpose To evaluate the MRI findings of renal cell carcinoma (RCC), including findings on diffusion-weighted images (DWIs) and chemical shift images (CSIs), in patients with acquired cystic disease of the kidney (ACDK) in relation to the histopathologic findings. Materials and Methods Two radiologists retrospectively reviewed the MRI findings of 10 RCCs in seven consecutive patients with ACDK. They evaluated the signal intensities (SIs) and signal homogeneity of the lesions on T2-weighted images, DWIs, and T1-weighted images. Thereafter, they evaluated the cytoplasmic fat in the lesions by CSIs. After image analyses, the MRI findings were correlated with the histopathologic findings. Results The RCCs tended to show heterogeneous high SIs on T2-weighted images and DWIs. The high SIs on DWIs were mainly attributable to the viable parts, and the heterogeneity was due to the various SIs arising from the intratumoral degenerative components. Unlike the reported findings for hemorrhagic cysts, the RCCs did not show homogeneous high SIs or fluid-iron levels on T1-weighted images. The four lesions, in which the presence of cytoplasmic fat was suggested on CSIs, were clear cell RCCs. Conclusion The MRI findings, including findings on DWIs and CSIs, well reflected the histopathologic findings of RCC in patients with ACDK. © 2013 Wiley Periodicals, Inc.

Context The volume of the pancreas increases with obesity.

Angiomyolipoma is the most common benign solid renal neoplasm observed in clinical practice. Once thought to be a hamartoma and almost always diagnosed by the imaged-based detection of fat, angiomyolipomas are now known to consist of a heterogeneous group of neoplasms. Although all are considered perivascular epithelioid cell tumors, many display different pathology, imaging features, and clinical behavior. The importance of understanding this group of neoplasms is emphasized by the fact that many types of angiomyolipoma contain little to no fat, and despite being benign, sometimes escape a pre-operative diagnosis. These types of angiomyolipomas can all be considered when encountering a renal mass that is both hyperattenuating relative to renal parenchyma on unenhanced CT and T2-hypointense, features that reflect their predominant smooth muscle component. We review recent developments and provide a radiological classification of angiomyolipomas that helps physicians understand the various types and learn how to both diagnose and manage them. © 2014 The Author(s).

Localized amyloidosis is a rare condition, especially that involving the ureter. Because of its rarity and the difficulty in differentiating this condition from urothelial carcinoma by intravenous urography and computed tomography, nephroureterectomy has often been performed unnecessarily for this disease. The authors encountered two cases of this disease, both of which showed a negative urine cytology, no obvious mass effect, and a hypointensity on T2-weighted imaging. Because these findings are very rare in urothelial carcinoma, ureteroscopy-guided biopsy was performed, which yielded the diagnosis of amyloidosis. The patients were then treated and followed up at our institute. Primary localized amyloidosis of the ureter should be considered when evaluating ureteric lesions visualized as hypointensities on T2-weighted images that do not show an obvious mass effect, which could help in the avoidance of unnecessary surgery. © 2011 Wiley Periodicals, Inc.

Purpose: To demonstrate the reduction in vascular bed volume (VBV) of uterine fibroids after administration of gonadotropin-releasing hormone analogue (GnRHa) using magnetic resonance (MR) imaging including dynamic double-echo R2* imaging (DDE-R2*I) and to assess the value of DDE-R2*I as a predictor of such reduction. Methods: Twenty-one women with uterine intramural fibroids underwent MR imaging including DDE-R2*I before GnRHa treatment. DDE-R2*I was acquired using a single-section, double-echo, fast spoiled gradient recalled acquisition in the steady state (SPGR) sequence. We calculated the area under the curve (AUC) of the signal intensity on R2*I within a 3×3-cm2 region of interest that served to represent the VBV. We repeated MR imaging after 2 administrations of GnRHa and repeated image analyses. We statistically analyzed correlations between (A) pre-treatment AUC (AUC(pre)) and AUC reduction and (B) AUC(pre) and volume reduction. Results: The interval between the 2 MR studies ranged from 56 to 119 days (mean: 80.4 days). The average volume of the fibroids before GnRHa treatment was 647.8 mL compared with 463.4 mL after the therapy (decreased by an average of 28.5z; P<0.0001). Meanwhile, measured AUC was reduced by 55.3z(483.4 vs. 206.5; P<0.0001). AUC(pre) correlated with volume reduction (r=0.68), but not AUC reduction. Conclusions: We confirmed reduction in the VBV of fibroids using DDE-R2*I. The measurement of AUC(pre) on DDE-R2*I aids prediction of fibroid volume reduction but correlates poorly with the percentage of AUC reduction.

Cardiac computed tomography angiography (CCTA) has emerged as a useful diagnostic imaging modality in the assessment of coronary artery disease. However, the potential risks due to exposure to ionizing radiation associated with CCTA have raised concerns. Several techniques such as "lower kVp", "step and shoot method" and "interative reconstruction" significantly reduce radiation dose without impairing image quality when compared with the standard retrospective helical data acquisition. These effective strategies to reduce radiation dose are available but some strategies are not frequently used. It is important to increase the use of dose-saving strategies in adequately selected patients.

Background In patients with rotator cuff tears, muscle degeneration is known to be a predictor of irreparable tears and poor outcomes after surgical repair. Fatty infiltration and volume of the whole muscles constituting the rotator cuff were quantitatively assessed using 3-dimensional 2-point Dixon magnetic resonance imaging. Methods Ten shoulders with a partial-thickness tear, 10 shoulders with an isolated supraspinatus tear, and 10 shoulders with a massive tear involving supraspinatus and infraspinatus were compared with 10 control shoulders after matching age and sex. With segmentation of muscle boundaries, the fat fraction value and the volume of the whole rotator cuff muscles were computed. After reliabilities were determined, differences in fat fraction, muscle volume, and fat-free muscle volume were evaluated. Results Intra-rater and inter-rater reliabilities were regarded as excellent for fat fraction and muscle volume. Tendon rupture adversely increased the fat fraction value of the respective rotator cuff muscle (P <.002). In the massive tear group, muscle volume was significantly decreased in the infraspinatus (P =.035) and increased in the teres minor (P =.039). With subtraction of fat volume, a significant decrease of fat-free volume of the supraspinatus muscle became apparent with a massive tear (P =.003). Conclusion Three-dimensional measurement could evaluate fatty infiltration and muscular volume with excellent reliabilities. The present study showed that chronic rupture of the tendon adversely increases the fat fraction of the respective muscle and indicates that the residual capacity of the rotator cuff muscles might be overestimated in patients with severe fatty infiltration.

Background: Image-based measurement of absorbed dose of Ra-223 dichloride may be useful in predicting therapeutic outcome in patients with castration-resistant prostate cancer (CRPC). In general, SPECT has been found to be more accurate than planar imaging in terms of lesion-based analysis. The aims of this study were to assess the feasibility and clinical usefulness of Ra-223 SPECT. The energy spectrum of Ra-223 and SPECT images of a cylindrical phantom with a hot rod were obtained to determine the collimator candidates and energy window settings suitable for clinical Ra-223 SPECT (basic study A). Another phantom with a tube-shaped chamber and two spheres simulating bowel activity and metastatic lesions in the lumbar spine was scanned with medium-energy general-purpose (MEGP) and high-energy general-purpose (HEGP) collimators (basic study B). Ten patients with CRPC underwent SPECT imaging 2 h after Ra-223 injection successively with MEGP and HEGP collimators in random order for 30 min each. Lesion detectability and semi-quantitative analyses of bone metastasis (i.e. lesion-to-background ratio (LBR)) were performed compared to Tc-99m HMDP SPECT. Results: Basic study A revealed that an 84-keV photopeak ± 20% using the HEGP collimator offers better SPECT image quality than the other imaging conditions. Basic study B showed that uptake in one of the spheres was overestimated by overlapped activity of the tube-shaped chamber in planar imaging whereas the spheres had similar counts and significantly higher sphere-to-background ratio in SPECT. On both planar and SPECT images, HEGP gave higher image contrast than MEGP (p < 0.01). In the clinical study, Ra-223 SPECT at 84 keV ± 20% depicted more lesions with the HEGP than with the MEGP collimator (51 vs 36, p = 0.013). There was a positive correlation between LBR in Tc-99m SPECT and in Ra-223 SPECT (r = 0.67 with the MEGP and 0.69 with the HEGP collimator, p < 0.01). LBRs were significantly higher with the HEGP than with the MEGP collimator (p < 0.01). Conclusions: We recommended the use of the HEGP collimator at 84 keV ± 20% for Ra-223 SPECT imaging. Lesion-based semi-quantitative analysis in the human study revealed a good correlation between Ra-223 and Tc-99m HMDP SPECT in the early phase (2–3 h post injection).

Objectives To investigate the relationship between small pulmonary vessels and extent of emphysema on CT in individual lungs with chronic obstructive pulmonary disease (COPD). Methods Forty-nine patients were included. The percentage of cross-sectional area of vessels < 5 mm2 (%CSA < 5) and extent of emphysema were assessed. Results Less than half of the COPD patients demonstrated an inverse correlation between %CSA < 5 and percentage of low attenuation area (LAA%). In the remaining patients, %CSA < 5 was homogeneously distributed. Conclusion Not all patients with COPD demonstrated an inverse correlation of the distributions between %CSA < 5 and LAA% in individual lungs.

Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. Purpose: Dual-energy computed tomography (DECT) can be used for visual determination of iodine distribution in the myocardium (iodine image); however, the accuracy and reproducibility of the process remains debatable. Because of the low contrast-to-noise ratio of CT, we hypothesized that quantitative measurement may be more accurate for detecting myocardial ischemia. In this study, we evaluated our quantitative method by comparing it with visual analysis using 99mTc-tetrofosmin (TF) stress-rest single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) as the reference standard. Materials and Methods: Forty-three patients who had a significant stenosis on cardiac rest DECT and had received 99mTc-TF stress-rest SPECT MPI within 1 month were retrospectively analyzed. The regions of interest were set on iodine images in accordance with the American Heart Association (AHA) 17-segment model (a total of 731 segments). The regions of interest values were divided by the amount of iodine (mg) per unit weight (kg) and defined as perfusion value (perfusion value analysis). All segments were also visually analyzed and receiver operating characteristic curve analysis performed to identify the superior analysis. Results: The receiver operating characteristic curve analysis showed that perfusion value analysis is significantly superior to visual analysis [the area under the curve: 0.921 (95% confidence interval, 0.860-0.981) versus 0.685 (95% confidence interval, 0.580-0.791), respectively, P<0.05], with 93.8% sensitivity, 99.1% specificity, 98.9% accuracy, 83.3% positive predictive value, and 99.7% negative predictive value (P<0.01). Conclusions: Quantitative analysis of the iodine image of rest DECT, called perfusion value analysis, is more accurate than visual analysis when compared with 99mTc-TF SPECT MPI as the reference standard.

This prospective study investigated radiation exposure dose (RED) to main operator (MO) and supervisory operator (SO) performing dypiridamole stress testing in a 1-d rest/stress 99mTc tetrofosmin single-photon emission computed tomography (SPECT) of consecutive 42 patients. MO was instructed to be close to the patients during the entire procedures including the vasodilator and radiotracer injection. SO mainly recorded the data on the procedures apart from the patients. RED, procedure time (PT) and internal radioactivity (IR) of patients were measured before and after a secondary tracer injection for stress SPECT, respectively. RED was significantly greater to MO than to SO (6.2 ± 2.7 vs 2.5 ± 2.1 μSV per stress procedure, p < 0.0001). Multivariate analyses revealed that IR and PT were significantly independent factors to predict RED to both operators. Operators performing pharmacologic stress procedure should be aware that IR and PT are independent factors for RED in 99mTc myocardial perfusion imaging.

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.

The purpose of this study was to compare renal cyst pseudoenhancement between virtual monochromatic spectral (VMS) and conventional polychromatic 120-kVp images obtained during the same abdominal computed tomography (CT) examination and among images reconstructed using filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR). Our institutional review board approved this prospective study; each participant provided written informed consent. Thirty-one patients (19 men, 12 women; age range, 59-85 years; mean age, 73.2±5.5 years) with renal cysts underwent unenhanced 120-kVp CT followed by sequential fast kVp-switching dual-energy (80/140kVp) and 120-kVp abdominal enhanced CT in the nephrographic phase over a 10-cm scan length with a random acquisition order and 4.5-second intervals. Fifty-one renal cysts (maximal diameter, 18.0±14.7mm [range, 4-61mm]) were identified. The CT attenuation values of the cysts as well as of the kidneys were measured on the unenhanced images, enhanced VMS images (at 70keV) reconstructed using FBP and ASIR from dual-energy data, and enhanced 120-kVp images reconstructed using FBP, ASIR, and MBIR. The results were analyzed using the mixed-effects model and paired t test with Bonferroni correction. The attenuation increases (pseudoenhancement) of the renal cysts on the VMS images reconstructed using FBP/ASIR (least square mean, 5.0/6.0Hounsfield units [HU]; 95% confidence interval, 2.6-7.4/3.6-8.4HU) were significantly lower than those on the conventional 120-kVp images reconstructed using FBP/ASIR/MBIR (least square mean, 12.1/12.8/11.8HU; 95% confidence interval, 9.8-14.5/10.4-15.1/9.4-14.2HU) (all P<.001); on the other hand, the CT attenuation values of the kidneys on the VMS images were comparable to those on the 120-kVp images. Regardless of the reconstruction algorithm, 70-keV VMS images showed a lower degree of pseudoenhancement of renal cysts than 120-kVp images, while maintaining kidney contrast enhancement comparable to that on 120-kVp images.

© 2020 Orthopaedic Research Society. Published by Wiley Periodicals LLC The degree of intervertebral disc (IVD) degeneration is qualitatively evaluated on T2-weighted imaging (T2WI). However, it is difficult to assess subtle changes in IVD degeneration using T2WI. Q-space imaging (QSI) is a quantitative diffusion-weighted imaging modality used to detect subtle changes in microenvironments. This study aimed to evaluate whether QSI can detect the inhibitory effects of the antioxidant N-acetylcysteine (NAC) in IVD degeneration. We classified female Wistar rats into control, puncture, and NAC groups (n = 5 per group). In the puncture and NAC groups, IVDs were punctured using a needle. The antioxidant NAC, which suppresses the progression of IVD degeneration, was orally administered in the NAC group 1 week prior to puncture. The progression and inhibitory effect of NAC in IVD degeneration were assessed using magnetic resonance imaging (MRI): IVD height, T2 mapping, apparent diffusion coefficient (ADC), and QSI. MRI was performed using a 7-Tesla system with a conventional probe (20 IVDs in each group). QSI parameters that were assessed included Kurtosis, the probability at zero displacement (ZDP), and full width at half maximum (FWHM). IVD degeneration by puncture was confirmed by histology, IVD height, T2 mapping, ADC, and all QSI parameters (P <.001); however, the inhibitory effect of NAC was confirmed only by QSI parameters (Kurtosis and ZDP: both P <.001; FWHM: P <.01). Kurtosis had the largest effect size (Kurtosis: 1.13, ZDP: 1.06, and FWHM: 1.02) when puncture and NAC groups were compared. QSI has a higher sensitivity than conventional quantitative methods for detecting the progressive change and inhibitory effect of NAC in IVD degeneration.

© 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. The purpose of this phantom study was to investigate the feasibility of dose reduction with hybrid iterative reconstruction, with and without a noise power spectrum (NPS) model, using both quantitative and qualitative evaluations. Standard dose (SD), three-quarter dose (TQD), and half-dose (HD) of radiation were used. Images were reconstructed with filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR 3D) (MILD, STR), and AIDR 3D enhanced (eAIDR 3D) (eMILD, eSTR). An NPS analysis, task-based modulation transfer function (MTFtask) analysis, and comparisons of low-contrast detectability and image texture were performed. Although the eAIDR 3D had a higher NPS value in the high-frequency range and improved image texture and resolution as compared with AIDR 3D at the same radiation dose and iteration levels, it yielded higher noise than AIDR 3D. Additionally, although there was no statistically significant difference between SD-FBP and the TQD series in the comparison of the mean area under the curve (AUC), the mean AUC was statistically significantly different between SD-FBP and the HD series. NPS values in the high-frequency range, 10% MTFtask values, low-contrast detectability, and image textures of TQD-eMILD were comparable to those of SD-FBP. Our findings suggested that using eMILD can reduce the radiation dose by 25%, while potentially maintaining diagnostic performance, spatial resolution, and image texture; this could support selecting the appropriate protocol in a clinical setting.

© Wolters Kluwer Health, Inc. All rights reserved. Objectives The aims of this study were to evaluate the feasibility of quantitative synthetic magnetic resonance imaging (SyMRI) for characterizing bone lesions in prostate cancer and to discriminate viable progressive osteoblastic bone metastasis from nonviable bone metastases with treatment-induced sclerosis during the treatment course. Materials and Methods This institutional review board-approved prospective study included 96 consecutive prostate cancer patients who underwent whole-body MRI including diffusion-weighted imaging at the time of staging at diagnosis or starting a new line of anticancer treatment. Additional synthetic MRI of the lumbosacral spine, pelvis, and proximal femurs was performed. A region of interest of 1.0 cm in diameter was set in each bone lesion by 2 independent readers who were blinded to bone lesions' diagnosis. Differences in SyMRI variables between the different bone lesions were compared with the Wilcoxon rank sum test, and associations of SyMRI variables with active disease were analyzed with logistic regression analysis. Performance of T1, T2, and proton density (PD) for diagnosing active disease was assessed using the area under the receiver operating characteristic curve. Results Ninety-three bone lesions were eligible for analysis. The PD values of active (viable) bone metastatic lesions were significantly higher than those of inactive (nonviable) bone metastatic lesions without sclerosis and those of red bone marrow (P < 0.001 for both readers). The PD values of inactive bone metastatic lesions with sclerosis were significantly lower than those of inactive bone metastatic lesions without sclerosis and red bone marrow (P < 0.001 for both readers). The PD value proved to be an independent significant indicator (P < 0.001) for differentiating bone lesions. The areas under the curve of T1/T2/PD for identifying active disease were 0.81/0.69/0.93 for reader 1 and 0.78/0.70/0.92 for reader 2, respectively. Conclusions Signal quantification on SyMRI provides objective assessment of bone lesions in the lower trunk. The PD value can be useful to determine the viability of bone metastases in prostate cancer.

© 2018 Elsevier Ltd Background and objective: No reports exist regarding skeletal muscle involvement in patients with Mycobacterium avium complex lung disease (MAC-LD). The cross-sectional area of the erector spinae muscles (ESMCSA) reflects physical activity and can be assessed by computed tomography (CT). We investigated the relationship between ESMCSA and physiological parameters and prognosis in MAC-LD patients. Material and methods: In this prospective observational study, the ESMCSA was measured on single-slice axial CT images. MAC-LD patients and sex- and age-matched controls (non-MAC-LD participants) were evaluated. We evaluated the relationship between the ESMCSA and physiological parameters and prognosis. Results: A total of 260 patients (209 female; median age, 69 years; 190 with nodular/bronchiectatic disease; 74 with cavitary lesions) were enrolled. The ESMCSA was not different between MAC-LD patients and controls. In MAC-LD patients, the ESMCSA was significantly associated with age, body mass index (BMI), pulmonary function, CT severity, and health-related quality of life (HRQL). Multivariate Cox proportional hazards analyses revealed that an ESMCSA < −1 standard derivation (hazards ratio [HR], 2.76; P = 0.047) was significantly associated with all-cause mortality, along with BMI < 18.5 kg/m2 (HR, 3.67; P = 0.02) and presence of cavitary lesions (HR, 5.84; P = 0.001). However, the ESMCSA was not significantly associated with all-cause mortality when current treatment status, % predicted functional vital capacity, and forced expiratory volume in 1 s were added to the analyses. Conclusions: Although the prognostic impact was limited, ESMCSA was significantly associated with HRQL and prognostic physiological parameters, such as BMI and pulmonary function.