Published papers

© 2018 The Authors. Objective: The diagnostic performance of endoscopic retrograde cholangiography (ERC) with radiography is imperfect. We assessed the value of adding tomosynthesis to ERC with radiography for the detection of choledocholithiasis. Methods: This study included 102 consecutive patients (choledocholithiasis/non-choledocholithiasis, n = 57/45), who underwent both radiography and tomosynthesis for ERC in the same examination and were not diagnosed with malignancy. The reference standard for the existence of choledocholithiasis was confirmed by endoscopic stone extraction during ERC, intraoperative cholangiography, or follow up with magnetic resonance cholangiopancreatography (n = 78, 11, and 13, respectively). A gastroenterologist and a radiologist independently evaluated the radiographs and the combination of tomosynthesis and radiographic images in a blinded and randomised manner. Receiver operating characteristic analysis was used for statistical analysis. Results: The areas under the receiver operating characteristic curve for combined tomosynthesis and radiography were significantly higher than those for radiography alone for both readers: Reader 1/ Reader 2, 0.929/0.956 [95% confidence interval (CI), 0.861-0.965/0.890-0.983) vs 0.803/0.769 (95% confidence interval, 0.707-0.873/0.668-0.846), respectively (p = 0.0047/> 0.0001). Conclusion: Adding tomosynthesis to radiography improved the diagnostic performance of ERC for detection of choledocholithiasis. Advances in knowledge: Adding tomosynthesis to radiography improves detection of choledocholithiasis and tomosynthesis images can be obtained easily after radiographs and repeated immediately.

© 2018, Springer-Verlag France SAS, part of Springer Nature. Purpose: Surgical procedures for impaired forearm rotation such as for chronic radial head dislocation remain controversial. We hypothesized that the morphological axis of the proximal radius is important for stable forearm rotation, and we aimed to clarify the relationship between the morphological axis and the kinematic axis of the proximal radius using four-dimensional computed tomography (4DCT). Methods: Ten healthy volunteers were enrolled. Four-dimensional CT of the dominant forearm during supination and pronation was obtained. The rotation axis of forearm rotation was calculated from all frames during supination and pronation. The principle axis of inertia, which represents the most stable rotation axis of a rigid body, was calculated for the proximal radius by extending its surface data incrementally by 1% from the proximal end. The angle between the kinematic rotation axis and the morphological rotation axis of each length was calculated. Results: The rotation axis of the forearm was positioned on the radial head 0.0 mm radial and 0.4 mm posterior to the center of the radial head proximally and 2.0 mm radial and 1.2 mm volar to the fovea of the ulnar head distally. The principle axis at 15.9% of the length of the proximal radius coincided with the forearm rotation axis (kinematic axis). Individual differences were very small (SD 1.4%). Conclusion: Forearm rotation was based on the axis at 16% of the length of the proximal radius. This portion should be aligned in cases of severe morphological deformity of the radial head that cause “rattling motion” of the radial head after reduction procedures.

BACKGROUND: Weightbearing of the hindfoot affects positional changes of the ankle joint and subtalar joint (ankle-joint complex [AJC]). However, it is difficult to assess the kinematic changes in the hindfoot in a natural full weightbearing condition using conventional CT or cone beam computed tomography (CT) due to limitations of acquiring foot images under a physiological weightbearing condition using those imaging modalities. Analysis of AJC kinematics using fluoroscopy and 2D-3D registration technique requires data on the number of steps and amount of time to build and match the bones. This study aimed to analyze the effect of full weightbearing on hindfoot motion when standing using upright CT and 3D-3D surface registration. METHODS: Forty-eight AJCs of 24 asymptomatic volunteers (13 women, 11 men) were examined under no weightbearing, 50% weightbearing, and single leg full weightbearing conditions while standing. The CT images were acquired from the distal femur to the whole foot using a 320-row upright CT scanner. The condition of each weightbearing stance was measured using a pressure mat. Bone-to-bone rotations of the talus relative to the tibia and calcaneus relative to the talus were evaluated using the surface registration technique. Image quality of the CT and intra- and interobserver reliabilities of the rotation angle were also evaluated. RESULTS: All CT images were excellent or good quality and the intra- and interobserver correlation coefficients for the angle were 0.996 and 0.995, respectively. The motion of the ankle joint and subtalar joint under 50% and 100% weightbearing were as follows (in degrees); the talus plantarflexed (5.1 ± 4.5 and 6.8 ± 4.8), inverted (1.3 ± 1.4 and 2.0 ± 1.6), and internally rotated (2.4 ± 4.2 and 4.3 ± 4.6) relative to the tibia, and the calcaneus dorsiflexed (2.8 ± 1.4 and 3.8 ± 1.7), everted (5.3 ± 2.6 and 8.0 ± 3.6), and externally rotated (3.0 ± 2.0 and 4.1 ± 2.4) relative to the talus, respectively. CONCLUSIONS: The effect of weightbearing was clearly identified using an upright CT and the 3D-3D registration technique. Three-dimensional kinematics under static full weightbearing were opposite between the ankle and subtalar joints on their respective axes.

© 2019 The Authors Objective: To assess diaphragmatic motion during forced breathing in a health screening center cohort by time-resolved quantitative analysis using dynamic chest radiography and demonstrate the characteristics and associations with demographics and pulmonary function of participants. Materials and methods: This prospective study includes 174 volunteers (99 males; median 57, range 36–93 years old) that underwent dynamic chest radiography with a flat panel detector system during forced breathing in a standing position. We automatically tracked and recorded the positions of the top of the diaphragms and the excursions on images of each participant and calculated peak motion speeds based on the data. We investigated the associations with demographics and pulmonary function statistically. Results: The average excursions of the diaphragms during forced breathing were 49.1 ± 17.0 mm (right; mean ± standard deviation) and 52.1 ± 15.9 mm (left). The peak motion speeds were 26.7 ± 10.0 mm/s (right) and 32.2 ± 12.4 mm/s (left) in the inspiratory phase and 22.1 ± 12.7 mm/s (right) and 24.3 ± 10.3 mm/s (left) in the expiratory phase. Excursions and peak motion speeds of the left diaphragm were significantly greater than the right. Higher body mass index (BMI) and vital capacity (VC) were associated with greater excursions and faster peak motion speeds of the diaphragms. Conclusions: Time-resolved quantitative analysis of the diaphragms with dynamic chest radiography demonstrated the characteristics of diaphragmatic motion during forced breathing in a health screening cohort. Higher BMI and VC were associated with excursions and peak motion speeds of the diaphragms.

© 2019 by the American Institute of Ultrasound in Medicine. A dermal sinus/fistula is a common condition; the relevant department should be consulted for appropriate treatment. It is important for radiologists to have adequate knowledge of these conditions to provide the correct diagnosis and recommend subsequent management. This review describes the following lesions: preauricular sinus, midline sinus of the upper lip, nasal dermoid sinus cyst, cheek fistula, first branchial cleft anomaly/sublingual branchial cleft anomaly, thyroglossal duct cyst/fistula, lateral cervical sinus/fistula, congenital dermal sinus/fistula of the anterior chest region, congenital skin sinus/fistula with a sternal cleft, and congenital prepubic sinus. On the basis of the skin orifice location and ultrasound images, radiologists can provide useful information to physicians.

© 2018, Japan Radiological Society. Anorectal malformation (ARM) is classified as low, intermediate, or high; accurate diagnosis of the type during the early neonatal period is important to determine the appropriate initial surgical approach. This review assesses the role of ultrasound examination in the classification of ARM during the neonatal period, with a focus on landmarks on the sonogram, the approach used for sonography, and the optimal examination timing. The following three factors on the sonogram are used for the classification: location of the fistula, the distance between the distal rectal pouch and the anal dimple (perineum) (P–P distance), and the relationship between the puborectalis muscle and the distal rectal pouch. Three approaches can be used to evaluate ARM by ultrasonography, namely, suprapubic, perineal, and infracoccygeal approaches. Each approach has its own advantages and disadvantages. Optimal timing of the ultrasound examination is also important with respect to each factor to classify ARM. We have described the pitfalls of ultrasound in diagnosis of cases, namely ARM with Down syndrome (which tends to be without fistula), ARM with low birth weight, ARM with unusual location of fistula, ARM with opened fistula (where the P–P distance is unreliable), and cloacal malformation (variation of the high-type ARM).

© 2017 RSNA. Purpose: To assess the value of a computer-Aided detection (CAD) system for the detection of pulmonary nodules on chest tomosynthesis images. Materials and Methods: Fifty patients with and 50 without pulmonary nodules underwent both chest tomosynthesis and multidetector computed tomography (CT) on the same day. Fifteen observers (five interns and residents, five chest radiologists, and five abdominal radiologists) independently evaluated tomosynthesis images of 100 patients for the presence of pulmonary nodules in a blinded and randomized manner, first without CAD, then with the inclusion of CAD marks. Multidetector CT images served as the reference standard. Free-response receiver operating characteristic analysis was used for the statistical analysis. Results: The pooled diagnostic performance of 15 observers was significantly better with CAD than without CAD (figure of merit [FOM], 0.74 vs 0.71, respectively; P = .02). The average true-positive fraction and false-positive rate per all cases with CAD were 0.56 and 0.26, respectively, whereas those without CAD were 0.47 and 0.20, respectively. Subanalysis showed that the diagnostic performance of interns and residents was significantly better with CAD than without CAD (FOM, 0.70 vs 0.62, respectively; P = .001), whereas for chest radiologists and abdominal radiologists, the FOM with CAD values were greater but not significantly: 0.80 versus 0.78 (P = .38) and 0.74 versus 0.73 (P = .65), respectively. Conclusion: CAD significantly improved diagnostic performance in the detection of pulmonary nodules on chest tomosynthesis images for interns and residents, but provided minimal benefit for chest radiologists and abdominal radiologists.

© American Roentgen Ray Society OBJECTIVE. The purpose of this study is to evaluate the association between sonographic findings and the operative time of transumbilical laparoscopic-assisted appendectomy (TULAA) for appendicitis in children. MATERIALS AND METHODS. We included 131 children who underwent ultrasound within 24 hours before TULAA. We evaluated the associations between operative time and patients’ demographics, as well as the following sonographic findings: maximum outer wall diameter of the appendix, appendicolith, ascites (not echogenic), echogenic ascites, abscess formation, increased intraabdominal fat echo in the right lower quadrant (RLQ; 3-point scale), and the location of the appendix (three locations). The results were analyzed using simple linear regression or the t test and a multiple liner regression model. RESULTS. The mean (± SD) patient age was 9.50 ± 2.92 years (range, 3–15 years), and the mean operative time was 73.04 ± 36.56 minutes (range, 25–210 minutes). Univariate analysis showed that higher body mass index, greater maximum outer wall diameter of the appendix, higher grade of intraabdominal fat echo in the RLQ, presence of appendicolith, presence of echogenic ascites, abscess formation, and location of the appendix in the pelvis were associated with increased operative time. Multivariate analysis found that abscess formation and higher grade of increased intraabdominal fat echo in the RLQ were independently associated with operative time (both p < 0.05). CONCLUSION. Preoperative sonographic findings of abscess formation and increased intraabdominal fat echo in the RLQ were factors independently associated with prolonged operative time for TULAA. On the basis of these sonographic findings, surgeons may predict additional surgical procedures, including abscess aspiration or adhesiolysis, and operative time before beginning the operation.

© 2018 by the American Institute of Ultrasound in Medicine. Objective—An anorectal malformation (ARM) in neonates requires urgent surgery, with the type of surgery being dependent on the type of malformation (low, intermediate, or high). Distal rectal pouch and perineum (pouch-perineum) distance is reported to be useful for differentiating the type of ARM; however, the impact of an opened fistula on pouch-perineum distance is not well known. The purpose of this study was to evaluate the difference in pouch-perineum distance between neonates with a low-type ARM with and without an opened fistula. Methods—We included 24 neonates with low-type ARM who underwent sonography before surgery. Eight neonates already had an opened fistula before sonography, and 16 did not. The pouch-perineum distance was measured using the perineal approach. Mann-Whitney U and Spearman’s correlation coefficient tests were used for statistical analysis. Results—The mean pouch-perineum distance in all neonates with a low-type ARM was 8.3 ± 2.9 mm. The pouch-perineum distance was substantially longer for an ARM with than without an opened fistula (10.6 ± 3.4 mm vs. 7.1 ± 1.7 mm; P =.02). No appreciable correlation was identified between the pouch-perineum distance and the postnatal day of examination (ρ =-.23, P =.26) or birth weight (ρ =.15, P =.47). Conclusion—The pouch-perineum distance is substantially longer in neonates with an ARM with an opened fistula than in those without an opened fistula. Caution should be exercised by the sonographic examiner in evaluating pouch-perineum distance in neonates with an opened fistula to prevent an incorrect surgical procedure based on misdiagnosis of the type of ARM.

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Background: Recently, it has been reported that anorectal malformation with rectourethral fistula in male neonates can be managed by primary neonatal reconstruction without colostomy. To prevent urethral injury during anorectoplasty, the fistula’s location is important. To date, the use of voiding cystourethrograms to determine the presence and location of fistulas in neonates with anorectal malformations has not been studied. Objective: To compare the accuracy of ultrasound (US) and voiding cystourethrogram for determining the presence and location of fistulas in neonates with anorectal malformation. Materials and methods: We included 21 male neonates with anorectal malformation with rectourethral fistula (n=16), rectovesical fistula (n=1) or no fistula (n=4) who underwent US and voiding cystourethrogram preoperatively on the day of surgery. Fistula imaging was classified into three grades (0–2), and grades 1–2 were considered fistula positive. We compared the imaging-based location of the fistula with surgical findings. Results: US performed significantly better than voiding cystourethrogram for determining the presence of fistulas (area under the receiver operating characteristic curve, 0.90 vs. 0.71, respectively; P=0.044) (diagnostic accuracy 85.7%, 95% confidence interval [95% CI] 63.7–97.0% and 52.4%, 95% CI 29.8–74.3%, respectively). In cases with fistulas detected by either modality, the accuracy of locating the fistula by US was 50.0% (95% CI 24.7–75.3%) and by voiding cystourethrogram was 100% (95% CI: 59.0–100%). Conclusion: US accurately detected, but did not accurately locate, fistulas in neonates with anorectal malformation. When planning primary neonatal reconstruction of anorectal malformation without colostomy, voiding cystourethrogram could provide additional information about fistula location.

© 2019 Elsevier B.V. Objective: To assess the diaphragmatic motion in chronic obstructive pulmonary disease (COPD) patients during forced breathing by time-resolved quantitative analysis using dynamic chest radiography and to demonstrate the characteristics and the difference from that in normal subjects. Materials and methods: Thirty-one COPD patients and a matched control of 31 normal subjects on age, sex, height, and weight, who underwent chest radiographs during forced breathing using dynamic chest radiography, were included in this study. COPD patients were classified based on the criteria of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) (GOLD 1, n = 3; GOLD 2, n = 12; GOLD 3, n = 13; GOLD 4, n = 3). We measured excursions and peak motion speeds of the diaphragms for each participant. We compared the results among GOLD 1/2, GOLD 3/4 groups and normal subjects and investigated associations between the data, and participants’ demographics, or pulmonary function. Results: The excursions of bilateral diaphragms were significantly decreased in the GOLD 3/4 group relative to normal subjects (right, 39.8 ± 15.3 mm vs. 52.7 ± 15.1 mm, P = 0.030; left, 43.7 ± 14.0 mm vs. 56.9 ± 15.5 mm, P = 0.017; mean ± standard deviation) and the GOLD 1/2 group (right, 39.8 ± 15.3 mm vs. 54.4 ± 16.7 mm, P = 0.036; left, 43.7 ± 14.0 mm vs. 60.5 ± 13.9 mm, P = 0.008). The peak motion speeds of the left diaphragm in the inspiratory phase were slower in the GOLD 1/2 group than in normal subjects (24.5 ± 8.0 mm/s vs. 33.6 ± 14.0 mm/s, P = 0.038), and in the GOLD 3/4 group than in normal subjects (25.6 ± 6.8 mm/s vs. 33.6 ± 14.0 mm/s, P = 0.067). The excursions of the diaphragms showed correlation with VC, %VC, and FEV 1 , while the peak motion speeds showed no significant correlation with pulmonary function tests. Conclusions: Time-resolved quantitative analysis of diaphragms with dynamic chest radiography indicated differences in diaphragmatic motion between COPD groups and normal subjects during forced breathing. The excursions of the diaphragms during forced breathing were significantly lower in the GOLD 3/4 group than those in the GOLD 1/2 group and normal subjects.

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Background: There are limited data on the sensitivity, specificity and accuracy of ultrasound for detecting colorectal polyps in children and young adults. Objective: To evaluate the diagnostic accuracy of ultrasound, without any colon preparation, for detecting colorectal polyps in pediatric patients and to determine the causes of false-negative results. Materials and methods: We included 74 children with clinical signs like rectal bleeding, abdominal pain or diarrhea who underwent both ultrasound and colonoscopy. We evaluated the diagnostic performance of ultrasound for detecting colorectal polyps before colonoscopy, which served as the reference standard. We used Fisher exact and Student’s t-tests for statistical analyses. Results: Fifteen pediatric patients were diagnosed with colorectal polyps in the transverse (n=3), descending (n=1) and sigmoid (n=6) colon, and rectum (n=5) by colonoscopy. The sensitivity, specificity and accuracy of ultrasound to detect colorectal polyps were 47% (7/15, 95% confidence interval [CI] 21–73%), 100% (59/59, 95% CI 94–100%) and 89% (66/74, 95% CI 80–95%), respectively. The volume (mean ± standard deviation) of polyps not detected by ultrasound was significantly smaller than that detected (270±380 mm3 vs. 4,600±3,900 mm3, P=0.0124). We observed a significant difference in the location between the polyps detected and not detected by ultrasound (rectal/non-rectal=0/7 vs. 5/3, P=0.0256). No significant age or gender difference was observed. Conclusion: The accuracy for detecting colorectal polyps by ultrasound was 89% (95% CI, 80–95%) in our cohort. Polyps found in the rectum and relatively smaller polyps accounted for several false-negative cases.

© Wolters Kluwer Health, Inc. All rights reserved. This study was performed to compare computed tomography (CT)- and ultrasonography (US)-derived detection rates of portal venous gas (PVG) in pediatric patients and investigate whether discrepancies between these modalities were influenced by patient age and interval between examinations. We included 25 children who underwent both CT and US within 2 days for evaluation of intestinal ischemia. McNemar test was used to compare the detection of PVG between the 2 modalities. The cohort was retrospectively divided into 2 groups based on whether comparable results were obtained via both modalities; the Mann-Whitney U test was used to compare patient age and interval between CT and US between these 2 groups. Among 25 children, CT and US yielded similar results in 17 patients regarding the presence or absence of PVG (median age/interval, 2 years [range, 0-17 years]/51 minutes [range, 2-1196 minutes]; 3/14 detected via both/not both modalities) and different results in 8 (median age/interval, 0 years [range, 0-15 years]/171.5 minutes [range, 64-1486 minutes]; 7/1 detected via US only/via CT only). There was a significant difference in PVG detection rate between US and CT (P = 0.034). Patient age did not differ significantly between the 2 groups (P = 0.206), but the interval between CT and US did (P = 0.025). In conclusion, the detection rate of PVG was higher with US, compared with CT, although the timings of the examinations could have influenced this finding. Ultrasonography could be useful for PVG detection in pediatric patients because it can be performed repeatedly at the bedside without radiation exposure.