Published papers

An 80-year-old man with castration-resistant prostate cancer received Ra injection to treat bone metastases. Two weeks after the injection, the patient underwent static Ra scan of the chest with medium-energy and high-energy collimators for 30 minutes each. Images obtained with the 2 collimators showed that uptake in metastatic lesions was visually clearer and semiquantitatively higher with the high-energy collimator. The use of HE collimator for Ra imaging in the early phase has been reported, and the present case suggests that in the late phase HE collimator would also be preferable to medium-energy collimator in terms of lesion-based evaluation.

[(15)O] H2O positron emission tomography (PET) has long been out of use in activation studies on the brain. Indeed, it is true that blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) has better spatial resolution and temporal resolution than PET, as well as no radiation exposure. However, PET and fMRI differ in their scope. Compared to fMRI, [(15)O] H2O PET offers advantages such as being quantifiable, less deteriorated by movement, and allowing for longitudinal studies. This article aimed to reassess the merits of PET in this context.

PURPOSE: To evaluate the MRI findings of retroperitoneal low-flow vascular malformations (RLVMs) correlated with histopathological findings. METHODS: Two radiologists reviewed the MRI findings of 4 RLVMs (3 with capillary malformations and 1 with a venous malformation). First, they evaluated the visibility, signal intensities, and signal homogeneity of each lesion on non-fat-suppressed breath-hold T2-weighted single-shot fast spin-echo (non-FS SSFSE) images and fat-suppressed T2-weighted fast spin-echo (FS T2-weighted FSE) images. Second, the kinetic patterns and the internal enhancement patterns were analyzed for each lesion on multi-phasic contrast-enhanced (CE) images. After these image analyses, the MRI findings were correlated with the histopathological findings. RESULT: Histopathologically, the 4 RLVMs did not exhibit remarkable degeneration and were present in the retroperitoneal fat tissue without clear capsules. On the non-FS SSFSE images, 3 of the 4 RLVMs could not be discriminated from the surrounding retroperitoneal fat tissue (invisible), and the remaining lesion was barely visible with an indistinct margin. On the FS T2-weighted FSE images, however, all the RLVMs were clearly visualized as homogeneous high-signal intensities. On the multi-phasic CE images, all the capillary malformations exhibited fast enhancement, while a venous malformation showed slow enhancement. Furthermore, the RLVMs tended to exhibit a centripetal filling pattern. CONCLUSION: The RLVMs blended in with the surrounding retroperitoneal fat tissue on non-FS SSFSE images, like phantoms, whereas they were clearly visualized on FS T2-weighted FSE images. On multi-phasic CE images, the RLVMs tended to exhibit a centripetal filling pattern. These imaging features may be useful diagnostic clues for RLVMs.

This study reports 6 cases of hemoptysis originating from infectious pulmonary artery pseudoaneurysms (PAPs). Selective pulmonary angiography revealed PAPs in 5 cases, and segmental pulmonary artery embolization was performed using coils and gelatin sponge particles. Systemic arterial embolization also was performed in 5 cases because of inadequate initial control or for shunts from systemic to pulmonary arteries. At a median follow-up time of 9 months (range, 25 d to 25 mo), no recurrence occurred, although 2 patients died of respiratory failure. Segmental artery embolization combined with systemic artery embolization may be useful in patients with hemoptysis secondary to PAPs.

This study reports 6 cases of hemoptysis originating from infectious pulmonary artery pseudoaneurysms (PAPs). Selective pulmonary angiography revealed PAPs in 5 cases, and segmental pulmonary artery embolization was performed using coils and gelatin sponge particles. Systemic arterial embolization also was performed in 5 cases because of inadequate initial control or for shunts from systemic to pulmonary arteries. At a median follow-up time of 9 months (range, 25 d to 25 mo), no recurrence occurred, although 2 patients died of respiratory failure. Segmental artery embolization combined with systemic artery embolization may be useful in patients with hemoptysis secondary to PAPs.

The present report describes 6 cases of adrenal venous sampling (AVS) in patients who underwent computed tomography (CT) during arteriography because cannulation of right adrenal veins was otherwise difficult. CT was performed during arteriography to obtain information on the location and direction of the right adrenal vein. Two right adrenal veins were visualized in 1 case. The right central adrenal vein was not visualized in 1 case owing to an injury from a previous unsuccessful AVS procedure, but the right renal capsular vein was well visualized. CT during arteriography could contribute to a high AVS success rate.

BACKGROUND: Quantifying detailed 3-dimensional (3D) kinematics of the foot in contact with the ground during locomotion is crucial for understanding the biomechanical functions of the complex musculoskeletal structure of the foot. Biplanar X-ray fluoroscopic systems and model-based registration techniques have recently been employed to capture and visualise 3D foot bone movements in vivo, but such techniques have generally been performed manually. In the present study, we developed an automatic model-registration method with biplanar fluoroscopy for accurate measurement of 3D movements of the skeletal foot. METHODS: Three-dimensional surface models of foot bones were generated prior to motion measurement based on computed tomography. The bone models generated were then registered to biplanar fluoroscopic images in a frame-by-frame manner using an optimisation technique, to maximise similarity measures between occluding contours of the bone surface models with edge-enhanced fluoroscopic images, while avoiding mutual penetration of bones. A template-matching method was also introduced to estimate the amount of bone translation and rotation prior to automatic registration. RESULTS: We analysed 3D skeletal movements of a cadaver foot mobilized by a robotic gait simulator. The 3D kinematics of the calcaneus, talus, navicular and cuboid in the stance phase of the gait were successfully reconstructed and quantified using the proposed model-registration method. The accuracy of bone registration was evaluated as 0.27 ± 0.19 mm and 0.24 ± 0.19° (mean ± standard deviation) in translation and rotation, respectively, under static conditions, and 0.36 ± 0.19 mm and 0.42 ± 0.30° in translation and rotation, respectively, under dynamic conditions. CONCLUSIONS: The measurement was confirmed to be sufficiently accurate for actual analysis of foot kinematics. The proposed method may serve as an effective tool for understanding the biomechanical function of the human foot during locomotion.

Background: Quantifying detailed 3-dimensional (3D) kinematics of the foot in contact with the ground during locomotion is crucial for understanding the biomechanical functions of the complex musculoskeletal structure of the foot. Biplanar X-ray fluoroscopic systems and model-based registration techniques have recently been employed to capture and visualise 3D foot bone movements in vivo, but such techniques have generally been performed manually. In the present study, we developed an automatic model-registration method with biplanar fluoroscopy for accurate measurement of 3D movements of the skeletal foot. Methods: Three-dimensional surface models of foot bones were generated prior to motion measurement based on computed tomography. The bone models generated were then registered to biplanar fluoroscopic images in a frame-by-frame manner using an optimisation technique, to maximise similarity measures between occluding contours of the bone surface models with edge-enhanced fluoroscopic images, while avoiding mutual penetration of bones. A template-matching method was also introduced to estimate the amount of bone translation and rotation prior to automatic registration. Results: We analysed 3D skeletal movements of a cadaver foot mobilized by a robotic gait simulator. The 3D kinematics of the calcaneus, talus, navicular and cuboid in the stance phase of the gait were successfully reconstructed and quantified using the proposed model-registration method. The accuracy of bone registration was evaluated as 0.27 ± 0.19 mm and 0.24 ± 0.19° (mean ± standard deviation) in translation and rotation, respectively, under static conditions, and 0.36 ± 0.19 mm and 0.42 ± 0.30° in translation and rotation, respectively, under dynamic conditions. Conclusions: The measurement was confirmed to be sufficiently accurate for actual analysis of foot kinematics. The proposed method may serve as an effective tool for understanding the biomechanical function of the human foot during locomotion.

OBJECTIVE. The objective of our study was to evaluate the effects of radiation dose reduction and the reconstruction algorithm used-filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), or model-based iterative reconstruction (MBIR)-on the measurement of abdominal visceral fat using CT. SUBJECTS AND METHODS. Standard-dose and low-dose abdominal CT examinations were performed simultaneously with automatic exposure control in 59 patients; the noise index for a 5-mm slice thickness was 12 for routine-dose CT and 24 for low-dose CT. The routine-dose CT images were reconstructed using FBP (reference standard), and the low-dose CT images were reconstructed using FBP, ASIR (so-called hybrid iterative reconstruction [IR]), and MBIR (so-called pure IR). In the 236 image series obtained, the visceral fat area was measured. Data were analyzed by the Pearson correlation coefficient test and a Bland-Altman difference analysis. RESULTS. The radiation dose of the low-dose abdominal CT examinations was 73.0% (mean) lower than that of routine-dose CT examinations. Excellent correlations were observed between the visceral fat areas measured on the routine-dose FBP images and those measured on the low-dose FBP, low-dose ASIR, and low-dose MBIR images (r = 0.998, 0.998, and 0.998, respectively; p < 0.001). A Bland-Altman difference analysis revealed excellent agreements, with mean biases of-0.47,-0.41, and 0.18 cm2 for the visceral fat area between the routine-dose FBP images and the low-dose FBP, low-dose ASIR, and low-dose MBIR images, respectively. CONCLUSION. A 73.0% reduction of the radiation dose would be possible in CT for the measurement of the abdominal visceral fat regardless of which reconstruction algorithm is used (i.e., FBP, hybrid IR, or pure IR).

The present report describes 6 cases of adrenal venous sampling (AVS) in patients who underwent computed tomography (CT) during arteriography because cannulation of right adrenal veins was otherwise difficult. CT was performed during arteriography to obtain information on the location and direction of the right adrenal vein. Two right adrenal veins were visualized in 1 case. The right central adrenal vein was not visualized in 1 case owing to an injury from a previous unsuccessful AVS procedure, but the right renal capsular vein was well visualized. CT during arteriography could contribute to a high AVS success rate.

Upper tract urothelial carcinoma is more rare than bladder cancer, although they are both categorized as urothelial carcinoma. Because of the low incidence, little clinical evidence is available regarding the treatment of the former. However, recently such evidence has slowly begun to accumulate. The guideline presented herein was compiled for the purpose of ensuring proper diagnosis and treatment by physicians involved in the treatment of upper tract urothelial carcinoma. We carefully selected 16 clinical questions essential for daily clinical practice and grouped them into four major categories: epidemiology, diagnosis, surgery and systemic chemotherapy/other matters. Related literature was searched using PubMed and Japan Medical Abstracts Society databases for articles published between 1987 and 2013. If the judgment was made on the basis of insufficient or inadequate evidence, the grade of recommendation was determined on the basis of committee discussions and resultant consensus statements. Here, we present a short English version of the original guideline, and overview its key clinical issues.