Characteristic MRI findings of shoulder, elbow, and wrist joints in wheelchair user.

OBJECTIVE: Wheelchair users frequently utilize their upper extremities for moving around in their daily life. Therefore, it is likely they may develop conditions of overuse in their joints, which could affect their activity and daily life. The purpose of this study is to clarify the actual conditions of the joints of wheelchair users using MRI. MATERIAL AND METHODS: Twenty-five wheelchair users and twenty able-bodied control volunteers participated in this study. We scanned MRI images of their right and left shoulders, elbows, and wrists. Two radiologists interpreted the images and made diagnoses for each of the joints. The number of diseases for each joint was compared between wheelchair users and able-bodied volunteers. RESULTS: The number of supraspinatus tendon tears was higher in wheelchair users than controls in the right (Rt.) (P < 0.05), left (Lt.) (P < 0.05), and bilateral (Bil.) (P < 0.05) shoulders. The number of elbow LP lesions (Rt. (P < 0.01), Lt. (P < 0.01), and Bil. (P < 0.05)) and the number of elbow lateral epicondylitis cases (Rt. [P < 0.05] and Lt. [P < 0.05]) were also higher in wheelchair users than that of control volunteers. Additionally, the number of wrist TFCC injuries in wheelchair users (Rt. [P < 0.01], Lt. [P < 0.01], and Bil. [P < 0.01]) was more than that of control volunteers. CONCLUSION: Our results suggest that there are several types of overuse injury in each joint. However, we hypothesize that these are not induced by driving wheelchairs, but instead by the "push up" movement characteristic for wheelchair users, according to the situations caused by each injury.

Clinical and anthropometric characteristics of non-obese non-alcoholic fatty liver disease subjects in Japan.

AIM: The underlying mechanism of non-obese non-alcoholic fatty liver disease (NAFLD) has not been fully elucidated. We classified patients with NAFLD by sex and body mass index and compared their clinical features to clarify the background pathophysiology of non-obese NAFLD. METHODS: A total of 404 patients with NAFLD were divided according to their body mass index (<25 [non-obese], 25 to <30 [obese], and ≥30 [severe obese]), and were further compared with 253 patients without obesity and NAFLD (non-NAFLD). RESULTS: The proportion of the individuals with non-obese NAFLD was 25.7% in men and 27.6% in women. The male and female non-obese NAFLD groups had lower skeletal muscle mass and muscle strength than the obese NAFLD groups. The visceral fat area, although low, was ≥100 cm2 in 59.3% of men and 43.8% of women. An increase in liver fat accumulation, hepatic fibrosis, homeostasis model assessment of insulin resistance, and leptin levels was modest in the non-obese NAFLD group compared with a marked increase in the obese NAFLD groups. The muscle mass of the non-obese NAFLD group was similar to that of the non-NAFLD group, but muscle steatosis was particularly common among women. Multivariate analysis revealed that the factors contributing to increased liver fat accumulation in the non-obese NAFLD group were visceral fat area, HbA1c, myostatin, and leptin. CONCLUSIONS: In patients with non-obese NAFLD, a sex difference was observed in the clinical features. In addition to increased visceral fat, decreased muscle mass and muscle strength, muscle atrophy (presarcopenia), and impaired glucose tolerance were considered to be important pathophysiological factors.

Change in MRI findings of medial collateral ligament injury in adolescent baseball players with no clinical symptoms over time.

OBJECTIVE: Elbow screening of adolescent baseball players began in 2014 using ultrasound, palpation, and dedicated magnetic resonance imaging (MRI). We frequently encountered subjects showing MCL injury on MRI but no clinical symptoms. We assessed variations in asymptomatic MCL injury findings at follow-up MRI, and clarified the pathogenesis of these findings. MATERIALS AND METHODS: Using a 0.2-T-dedicated MRI, 30 subjects with asymptomatic MCL injury at initial MRI who agreed to follow-up MRI were included. We classified the findings at repeat MRI as follows: (a) disappeared, (b) better, and (c) worse. RESULTS: There were 6, 16, and 8 subjects in groups a, b, and c, respectively. The average age at follow-up was 14.0, 12.1, and 12.4 years in groups a, b, and c, respectively. There were significant differences between groups a and b and between groups a and c. Average height at follow-up of groups a, b, and c was 1.64, 1.52, and 1.57 cm, respectively, with a statistically significant difference between groups a and b. The average size of the short axis of the MCL of subjects in group a was 2.0 cm on the dominant side and 1.5 cm on the contradominant side (P < 0.04). CONCLUSION: Players with asymptomatic MCL injury can continue to play baseball with no limitations, as these findings usually disappear around the age of 14.0 years, when the growth spurt occurs. This finding may be a precursor of 'adaptation', which is generally observed in high school baseball players, suggesting that the MCL adapts as growth occurs.

Normal imaging laterality on magnetic resonance imaging of the medial epicondyle of the elbow on the dominant side of adolescent male baseball players.

OBJECTIVE: Multimodality elbow screening of adolescent baseball players shows apparent laterality in morphology and signal intensity of the medial epicondyle on dedicated magnetic resonance imaging. We aimed to elucidate actual imaging laterality in the medial epicondyle by comparing magnetic resonance images of the dominant and contradominant elbows and to clarify the clinical meaning and mechanism of this phenomenon. MATERIALS AND METHODS: We used a 0.2-T dedicated magnetic resonance imaging scanner. Eighty adolescent baseball players were enrolled and divided into four age groups: 9-10 years (13 patients); 11 years (28 patients); 12 years (24 patients) and 13-14 years (15 patients). The long and short axes of the ossification center and distance of the epiphyseal plate and the cartilage of the lower pole of the medial epicondyle were measured. Signal intensity of the ossification center was visually evaluated. RESULTS: Owing to their age, ossification and cartilage size on the dominant side were significantly larger in all boys (P < 0.01). All age groups had larger ossification and cartilage in the dominant elbow (P < 0.01). Ossification showed an apparent lower signal intensity on the dominant side (P < 0.01). CONCLUSIONS: Larger ossification and cartilage size of the medial epicondyle in the dominant elbow suggested that the medial collateral ligament to the medial epicondyle induces excessive repetitive tensile stress, but without clinical symptoms. Functional or microanatomical damage of the medial epicondyle may induce a lower ossification signal in the dominant elbow, thereby decreasing fatty bone marrow and inducing sclerotic changes.

Endoleak detection after endovascular aneurysm repair using unenhanced MRI with flow suppression technique: Feasibility study in comparison with contrast-enhanced CT.

OBJECTIVES: To evaluate the feasibility of unenhanced motion-sensitized-driven equilibrium (MSDE)-prepared balanced turbo field echo (BTFE) sequences for detecting endoleaks after endovascular aneurysm repair (EVAR). METHODS: Forty-six patients treated with EVAR for aortic and/or iliac arterial aneurysms underwent contrast-enhanced CT and MSDE-prepared BTFE sequences with and without flow suppression. Two independent observers reviewed these sequences and their subtraction images and assigned confidence levels for detecting endoleaks. Relative contrast values were calculated by dividing signal intensities by those of paraspinal muscles. CT provided the reference standard. RESULTS: CT showed types I and II endoleaks in one and ten patients, respectively. Areas under receiver operating characteristic curves were 0.92 and 0.97 for observers 1 and 2, respectively. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of both observers were 91 (10/11), 91(32/35), 91 (42/46), 77 (10/13) and 97 % (32/33), respectively. Relative contrast values of endoleaks and flowing blood significantly decreased by flow suppression on MSDE-prepared BTFE images (P = 0.002 and P < 0.0001 respectively), and were significantly higher than those of the excluded aneurysms on subtraction images (P = 0.003 and P = 0.001, respectively). CONCLUSIONS: Unenhanced MSDE-prepared BTFE sequences are feasible for detecting endoleaks. KEY POINTS: • Flow suppression significantly reduces endoleak signals on MSDE-prepared BTFE images. • Subtraction images of MSDE-prepared BTFE sequences ± flow suppression demonstrate endoleaks. • MSDE-prepared BTFE sequences indicate high diagnostic values (>90 %) except PPV (77 %). • MSDE-prepared BTFE sequences need further refinement to reduce false positives. • Endoleaks can be detected without contrast injection using MSDE-prepared BTFE sequences.

Traction MRI of the Elbow: Age-Based Effects and Implications.

BACKGROUND/OBJECTIVES: We previously reported that traction magnetic resonance imaging (MRI) of the elbow without arthrography increases the width of the radiocapitellar joint (RC) and improves articular cartilage visibility. However, the effects of axial traction on different age groups have not yet been evaluated. We hypothesized that the effect of traction would decrease as the participants' age increased. METHODS: We enrolled 30 healthy volunteers, ten each in their 20s, 30s, and 40s. The male-to-female ratio in each age group was 1:1. Elbow MRI was performed without traction and with 3, 5, and 7 kg axial traction. We evaluated joint space width (JW), humeral articular cartilage visibility, and intraprocedural pain/discomfort. We measured JW and cartilage visibility at the RC and the lateral and medial thirds of the ulnohumeral joint. RESULTS: The older age groups exhibited narrower JWs without traction. Axial traction increased the JW and improved the visibility of the RC in all age groups. No significant differences were observed in the ulnohumeral joint's lateral or medial thirds, but pain and discomfort increased with heavier traction weights. CONCLUSIONS: For participants in their 20s and 30s, axial traction of 3 kg seemed appropriate, while 7 kg traction was considered for those in their 40s.

Hip and lumbosacral joint centre locations in asian population: Biases produced by existing regression equations and development of new equations.

The hip and lumbosacral joint centre (HJC and LSJC) predictions are required to analyse the lumbo-pelvic-hip dynamics during various human motions. Some HJC and LSJC regression equations based on pelvic dimension have been developed; however, the pre-existing methods need to be re-evaluated, and methodological reconsideration may improve the regression methods. Here we show that pre-existing methods produce biased predictions of the LSJC and HJC in 23 male and 24 female Japanese adults, and that the biases in the LSJC differ between sexes, using magnetic resonance imaging (MRI) around the pelvis. Compared with directly measured locations on MRI, the pre-existing regression equations predict LSJC to be more posterior in males and more inferior and posterior in females, and HJC to be more medial in both sexes. The better pre-existing regression equation for LSJC height differs between sexes, with pelvic-width-base better in males and pelvic-depth-base better in females, respectively. We suggest the unsuitability of pre-existing methods to our dataset consisting of Japanese adults and the importance of considering sex differences in regression methods. We propose regression equations to predict HJC and LSJC, considering soft-tissue thickness, sex differences, and a height-directional measure, using least absolute shrinkage and selection operator regression. We validate them using leave-one-out cross-validation (LOOCV). LOOCV shows that our model produces negligible biases and smaller absolute errors than the pre-existing regressions; in particular, the anteroposterior absolute error for LSJC is less than half that of the pre-existing regression. Our regression equation can be a powerful solution for accurate motion analysis.

Optimization of Traction Magnetic Resonance Imaging to Improve Visibility of the Elbow Cartilage.

We previously reported that elbow magnetic resonance imaging (MRI) with 7 kg traction increases the joint space width of the radiocapitellar joint and improves articular cartilage visibility without arthrography. However, the optimal traction weight remains unclear. We assessed the effects of different traction weights on elbow MRI in 30 healthy volunteers. Elbow MRI was performed without traction and with 3, 5, and 7 kg axial tractions. The joint space width, humeral articular cartilage outline visibility, and intraprocedural pain/discomfort were evaluated. The joint and cartilage parameters were measured at the radiocapitellar joint and the lateral and medial thirds of the ulnohumeral joint. At the radiocapitellar joint, the joint space width increased significantly with traction. The cartilage outline visibility significantly increased with traction, with no significant differences among the traction weights. No significant result was observed at the lateral and medial thirds of the ulnohumeral joint. Pain and discomfort significantly increased as we used heavier traction weights. Elbow MRI with 3 kg traction showed sufficient effects similar to those observed with 7 kg traction with minimal pain and discomfort. There was no difference in the effect of traction between male and female participants. This procedure may enable enhanced visualization of intra-articular elbow injuries.

Usefulness of fat attenuation index in postmortem CT for identifying responsible vessels in acute coronary syndromes: A case report.

Postmortem imaging, particularly unenhanced postmortem computed tomography (PMCT), has been increasingly utilized for pathological or judicial examination as a substitute for conventional autopsy, to compensate very low autopsy rates. While unenhanced PMCT has a limitation in diagnosing acute coronary syndromes, the fat attenuation index (FAI) which is a novel imaging biomarker measured by clinical coronary CT angiography (CCTA), has been known to noninvasively detect coronary artery inflammation. We investigated the postmortem diagnostic usefulness of perivascular FAI measured by CCTA in a 61-year-old male who died suddenly after chest pain. PMCT and autopsy were conducted 92 hours after death. FAI measurement results were -57 Hounsfield units (HU) in the right coronary artery (RCA), -73 HU in the left anterior descending artery (LAD), and -64 HU in the left circumflex artery (LCX). Autopsy revealed significant stenosis in the RCA and LCX, but no significant stenosis was found in the LAD. The elevated FAI in the RCA suggested acute inflammation, which agreed with the autopsy findings. This case is the first to demonstrate effectiveness of FAI measured with PMCT for identifying the vessels responsible for acute coronary syndromes, indicating its potential in postmortem diagnosis.

Development of a Car-mounted Mobile MR Imaging System for Diagnosis of Sports-related Wrist Injury.

Portable MRI scanners, in which a permanent magnet with a low magnetic field is mounted on a small car, have enabled the performance of MRI examinations in various remote environments. Here, we have modified the portable MRI system to enable the early diagnosis of wrist sports injuries among tennis players. A RF probe specifically designed for the human wrist was developed, and a power supply scheme using a small generator was introduced. The portable MRI system was located at a tennis school and imaging of the wrists of junior tennis players was performed. To demonstrate clinical feasibility, image quality was assessed by a radiologist and clinical evaluations were performed. In most cases, the image quality was sufficient for diagnosis, and triangular fibrocartilage complex damage could be detected. The results indicated that the modified portable MRI system could be applied for an early diagnosis of wrist injuries.

Consideration on size, velocity and path of droplets emitted during running.

BACKGROUND: People began to wear face masks during physical activities due to spread of COVID-19. There are no previous studies about the need for wearing masks while running. METHODS: Assuming a citizen runner who runs full marathon in 4 hours, we verified the path and the amount of droplet dispersal, setting a humanoid mannequin with a mask in simulated running environment (Experiment 1). We also had six adults exercise in the same environment to examine droplet behaviors when not wearing a face mask (Experiment 2). Average droplet size was determined, and repeated measures ANOVA was carried out to examine statistical significance. To evaluate observed droplet behaviors, theoretical solutions of the downfall motion of large droplets were then derived, taking air resistance into consideration. RESULTS: Experiment 1: wearing a face mask caused more droplets to adhere to the face; Experiment 2: droplets were emitted in conversation, coughing or sneezing, and they fell within social distancing. Average droplet size was not sensitive to the wind velocity. It could vary with a significant difference for time and wind velocity. Observed velocity and path of droplet can be expressed by the theoretical solutions. CONCLUSIONS: Velocity and path of large droplets can be expressed by the theoretical solution of particles in downfall motion under air resistance. We therefore conclude that wearing a mask while running gives adverse effects in preventing infection. Possibility of droplet transmission while running is considered low even when not wearing a face mask, as long as social distancing is ensured.

Distal muscle cross-sectional area is correlated with shot put performance.

Shot putters throw a heavy shot by "pushing". Pushing involves the coordinated extension of multiple joints and is a common motor task for both upper and lower limbs. In lower limb musculature, proximal-specific development and association with motor performance have been shown in athletes. However, as the upper limb is not mechanically loaded to support the body during daily locomotion, it may develop differently from the lower limb. We investigated the cross-sectional area of the prime movers of the upper limb and upper trunk (pectoralis major, deltoid, triceps brachii, and palmar flexors) in eleven male shot put athletes and fourteen untrained males by obtaining magnetic resonance images and manually tracing the muscles on the images. All target muscles were significantly larger in athletes than non-athletes (p < 0.01), with "huge" effect sizes for the pectoralis major and palmar flexors (d = 2.74, 2.04). All target muscle cross-sectional areas were positively correlated with season best record (r ≥ 0.62, p ≤ 0.04), with a particularly strong correlation for the palmar flexors (r = 0.96). These results suggest that the distal muscles of the upper limb are also expected to develop and are strongly associated with motor performance. This is especially true for the distal upper limb muscles (palmar flexors) in shot putters. These findings provide insight into potential training interventions for athletic performance in forceful upper limb movements.

Diffusion property differences of the lower leg musculature between athletes and non-athletes using 1.5T MRI.

OBJECT: To compare the differences in diffusion properties--namely fractional anisotropy (FA), three eigenvalues of the diffusion tensor (λ1, λ2, and λ3), and apparent diffusion coefficient (ADC)--between athletically-trained and untrained lower leg musculature. MATERIALS AND METHODS: Twelve athletes (Group A) and 11 non-athletes (Group B) were recruited. All were females in their 20s. We scanned diffusion tensor images of both calves and compared FA, the three eigenvalues, and ADC in the gastrocnemius medialis, gastrocnemius lateralis, soleus (SOL), and anterior tibialis muscles between Groups A and B, and between the right and left sides, using two-factor fractional ANOVA. RESULTS: In all muscles of bilateral calves, all three eigenvalues and ADC were lower in Group A than in Group B, with statistically significant differences in all muscles for λ1, λ2, and λ3 and ADC, with a P value of <0.01. Moreover, statistical differences were also found between right and left for λ1, λ2, and λ3 (P < 0.05), and ADC (P < 0.01) of the SOL muscle. FA showed no statistically significant differences in any muscles. CONCLUSIONS: Our results indicate that training causes a decrease of the three eigenvalues and ADC, which we hypothesize is due to an increase of density of myofilaments in the intracellular space, and deformation of the cell induced by enlargement of extracellular components.

Correlation of histopathology with magnetic resonance imaging in Kienböck disease.

PURPOSE: Diagnosis and treatment remain controversial for Kienböck disease. A few reports have correlated magnetic resonance imaging (MRI), which is essential for early diagnosis, and histopathology of Kienböck biopsy specimens, but histopathological correlations of whole lunate bones or histological slices compared with MRI images are lacking. The purpose of this study was to compare presurgical MRI scans with corresponding histological slices of Kienböck-diseased lunates. METHODS: We excised whole lunates at the time of surgery from 6 patients with Kienböck disease (stage IIIB) undergoing tendon-ball replacement or a Graner procedure. We stained paraffin-embedded, coronally sectioned specimens with hematoxylin-eosin and compared them with presurgical coronal scans using MRI with a 47-mm microscopy surface coil. RESULTS: Toward the center of the lunates, the signal intensity in the proton density-weighted images was reduced, whereas the dorsal and palmar sides of the lunates exhibited no changes in intensity. In correlation, histopathological findings revealed strongly disrupted trabeculae toward the center of the lunates and intact trabeculae in the dorsal side of the lunates. Likewise, the necrotic and vitalized bone exhibited low and high signal intensities, respectively, in the proton density-weighted images; however, in the fast-field echo images, there were no correlations with histopathological observations. CONCLUSIONS: Proton density-weighted MRIs but not fast-field echo images using a 47-mm microscopy coil reflected the extent and localization of the necrotic area in Kienböck-diseased lunates, as evidenced by comparison with histological analyses of the lunate specimens. CLINICAL RELEVANCE: Proton density-weighted MRIs accurately reflect the vascular status of the lunate and may help plan treatment on a case-by-case basis.

Advances in Bone Joint Imaging-Metal Artifact Reduction.

Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.

Two case reports showing a rather striking abnormal finding of unknown origin localized to the cortex of an amputated femur.

MRI scans of patients who have undergone leg amputation are rarely obtained; such scans may be performed when a mass is suspected to be related to the amputation or when inflammation (infection) is suspected, but the number of such cases is not large. In this study, however, we encountered 2 very striking cases in which short-tau inversion recovery coronal images taken for different purposes coincidentally showed a diffuse high signal intensity of the residual femoral cortex on the side wearing the artificial limb. Further examination of these images revealed that the superior margins of the artificial limb cup and the abnormal signal were almost identical and that the signal was only observed in the residual femur of the side using the artificial limb, suggesting that the change was caused by artificial limb usage. Despite the difficulty in imaging-pathologic correlation because the patients were still alive, we considered that the high signal was related to the characteristic microanatomy of the bone cortex and the mechanical changes caused by the effects of artificial limb usage on the residual femur. The 2 patients have not shown any specific events since then. Thus, while the residual femoral cortex may show findings of interest, these findings do not seem to require any specific treatment.

Characteristic MRI findings of the shoulder, elbow, and wrist joints in elite wheelchair basketball players.

BACKGROUND: The health of wheelchair users' upper limbs is directly related to their quality of life. Moreover, para-sport athletes are subjected to a dual load on their upper extremities from competition and daily life, making it even more critical to maintain upper extremity health. This study aimed to investigate the characteristics of joint disorders in elite wheelchair basketball players using magnetic resonance imaging (MRI). METHODS: We scanned MRI images of the bilateral shoulders, elbows, and wrist joints of ten elite wheelchair basketball players and ten general wheelchair users. The elite wheelchair players were athletes who underwent at our institution medical checkup of the candidates for the national team for the international women's tournament and who agreed to this research purpose. The general wheelchair players were recruited from wheelchair users in their 20s and 30s who had no daily exercise habits and who agreed to the study objectives. Two radiologists interpreted the MRI images and diagnosed the diseases of each joint. We compared the number of lesions between the two groups. We used Fisher's exact test to determine whether the lesions diagnosed by MRI were specific to wheelchair basketball players. The significance threshold was set at P < 0.05. RESULTS: Elite wheelchair basketball players had significantly more right-sided, left-sided and bilateral latero-posterior lesions, which are cysts found on the lateral-posterior corner of the capitulum of the humerus than did general wheelchair users (P < 0.05). Severe damage to the right triangular fibrocartilage complex was also observed more frequently (P < 0.05) in wheelchair basketball players. CONCLUSIONS: We believe that the patients' tendency to fall forward in the wheelchair hitting both hands on the ground, thereby injuring the triangular fibrocartilage complex and locking the lateral elbow, may be the cause of the characteristic findings on MRI. High-speed wheelchair operation was also considered a cause of severe triangular fibrocartilage complex injuries. This study's insights can be useful for future solutions to extend players' careers.

Use of a Small Car-Mounted Magnetic Resonance Imaging System for On-Field Screening for Osteochondritis Dissecans of the Humeral Capitellum.

Mobile magnetic resonance imaging (MRI) using a car is a recent advancement in imaging technology. Specifically, a car-mounted mobile MRI system is expected to be used for medical check-ups; however, this is still in the research stage. This study demonstrated the practicality of a small car-mounted mobile MRI in on-field screening for osteochondritis dissecans (OCD) of the humeral capitellum. In the primary check-up, we screened the throwing elbows of 151 young baseball players using mobile MRI and ultrasonography. We definitively diagnosed OCD at the secondary check-up using X-ray photography and computed tomography or MRI. We investigated the sensitivity and specificity of mobile MRI and ultrasonography for OCD. Six patients were diagnosed with OCD. The sensitivity was 83.3% for mobile MRI and 66.7% for ultrasonography, with specificity of 99.3% vs. 100%, respectively. One patient was detected using ultrasonography but was missed by mobile MRI due to poor imaging quality at the first medical check-up. Following this false-negative case, we replaced a damaged radio frequency coil to improve the image quality, and the mobile MRI could detect all subsequent OCD cases. Two patients were diagnosed by mobile MRI only; ultrasonography missed cases lacking subchondral bone irregularity, such as a healing case, and an early-stage case. Mobile MRI could screen for OCD from the very early stages through the healing process and is therefore a practical tool for on-field screening.

Effectiveness of temporal subtraction computed tomography images using deep learning in detecting vertebral bone metastases.

PURPOSE: To assess the clinical effectiveness of temporal subtraction computed tomography (TS CT) using deep learning to improve vertebral bone metastasis detection. METHOD: This retrospective study used TS CT comprising bony landmark detection, bone segmentation with a multi-atlas-based method, and spatial registration of two images by a log-domain diffeomorphic Demons algorithm. Paired current and past CT images of 50 patients without vertebral metastasis, recorded during June 2011-September 2016, were included as training data. A deep learning-based method estimated registration errors and suppressed false positives. Thereafter, paired CT images of 40 cancer patients with newly developed vertebral metastases and 40 control patients without vertebral metastases were evaluated. Six board-certified radiologists and five radiology residents independently interpreted 80 paired CT images with and without TS CT. RESULTS: Records of 40 patients in the metastasis group (median age: 64.5 years; 20 males) and 40 patients in the control group (median age: 64.0 years; 20 males) were evaluated. With TS CT, the overall figure of merit (FOM) of the board-certified radiologist and resident groups improved from 0.848 to 0.876 (p = 0.01) and from 0.752 to 0.799 (p = 0.02), respectively. The sub-analysis focusing on attenuation changes in lesions revealed that the FOM of osteoblastic lesions significantly improved in both the board-certified radiologist and resident groups using TS CT. The sub-analysis focusing on lesion location showed that the FOM of the resident group significantly improved in the vertebral arch (p = 0.04). CONCLUSIONS: TS CT was effective in detecting bone metastasis by both board-certified radiologists and radiology residents.