Okamura A, Takahashi T, Nemoto M
… +1 more, Okamura YT
J Med Ultrason (2001)
· 2026 May · PMID 42106512
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PURPOSE: Transabdominal pancreatic ultrasound is simple and noninvasive; however, the image quality is often degraded by visceral fat and gastrointestinal gas. Water intake pancreatic ultrasonography (WPUS) may help addr...PURPOSE: Transabdominal pancreatic ultrasound is simple and noninvasive; however, the image quality is often degraded by visceral fat and gastrointestinal gas. Water intake pancreatic ultrasonography (WPUS) may help address this limitation, but quantitative evidence remains limited. We evaluated the effects of WPUS and examined the 10-grade Pancreatic Image Scale (PIS) as a quality control metric. METHODS: We retrospectively reviewed the medical records of 581 patients who underwent WPUS. The PIS (0-9) was recorded before and after water intake, and improvements were analyzed for associations with body mass index (BMI), age, and sex to identify factors influencing pancreatic visualization. We added a reproducibility study in which three gastroenterologists independently re-scored 30 anonymized cases three times. RESULTS: WPUS improved pancreatic visualization in 82% of cases; the proportion achieving PIS ≥ 6 increased from 17% in pre-water supine scans to 54-71% after WPUS (P < 0.001). Higher BMI was associated with lower baseline PIS (β = - 0.12, P < 0.001). WPUS-related improvement was significantly greater in women than in men (β = 0.99, 95% CI 0.56-1.42, P < 0.001). PIS demonstrated moderate-to-good repeatability (intra-reader ICC 0.80; inter-reader ICC 0.71). CONCLUSION: Factor analysis indicated no sex difference in pre-WPUS pancreatic visualization, but women exhibited greater improvement after water intake. WPUS significantly improved visualization of the pancreatic body and tail, as reproducibly quantified using PIS. These findings support WPUS as a practical tool for routine clinical assessment and as a potential adjunct to early detection strategies for pancreatic disease.
Hata T, Konishi M, Koyanagi A
… +3 more, Miyagi Y, Miyake T, Hayashi N
J Med Ultrason (2001)
· 2026 May · PMID 42101568
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PURPOSE: To measure embryonic nuchal translucency (NT) thickness and ductus venosus (DV) blood flow indices using transvaginal two-dimensional sonography and Doppler ultrasound at 8-10 + 6 weeks. METHODS: Transvaginal sc...PURPOSE: To measure embryonic nuchal translucency (NT) thickness and ductus venosus (DV) blood flow indices using transvaginal two-dimensional sonography and Doppler ultrasound at 8-10 + 6 weeks. METHODS: Transvaginal scans were performed for 149 normal and three abnormal embryos (trisomy 18 with ventricular septal defect (VSD), tricuspid insufficiency (TR), and intrauterine fetal death with trisomy 21) at 8-10 + 6 weeks. NT thickness, S wave (cm/s), D wave (cm/s), "a" wave (cm/s), S/a, pulsatility index (PI), and resistance index (RI) of DV were measured, and reference values for each parameter were determined. RESULTS: NT, S, D, S/a, PI, and RI increased linearly with advancing gestation (p < 0.01). The 'a' (mean, 5.55 cm/s; SD, 1.8 cm/s) value was constant at 8-10 + 6 weeks of gestation. There were significant linear correlations between NT, S, D, S/a, PI, and RI, and crown-rump length (CRL) (p < 0.01). The "a" value remained unchanged with increasing CRL during this period. NT thickness (2.8 mm) in the trisomy 18 patient with VSD was high at 10 + 6 weeks, and reversed "a" wave was evident in the patient with TR at 10 + 1 weeks. In a fetus with intrauterine fetal death with trisomy 21 at 11 weeks and 6 days, NT thickness was 2.1 mm, and reversed DV flow was noted at 9 weeks and 6 days. CONCLUSION: Our results provide reference values for NT thickness and DV flow parameters, which may advance our understanding of embryonic growth and promote earlier prenatal diagnosis of chromosome abnormalities and/or cardiac anomalies before 11 weeks.
PURPOSE: To determine in vitro the efficacy and safety of thrombolysis in blood from Japanese subjects using standard diagnostic ultrasound (US) with or without microbubbles. METHODS: Blood from six healthy Japan-dwellin...PURPOSE: To determine in vitro the efficacy and safety of thrombolysis in blood from Japanese subjects using standard diagnostic ultrasound (US) with or without microbubbles. METHODS: Blood from six healthy Japan-dwelling Japanese (mean age 22.3 years), who have relatively low susceptibility to thrombosis because of heredity and dietary habits, was left at room temperature for 24 or 72 h. Each clot-containing well was submerged in a 150-mL heparin-physiologic saline bath (5 units heparin/mL) and rotated at 180 rpm. The 30-min US treatment conditions were: (1) no US or microbubbles; (2) grayscale US (4.5 MHz); (3) color Doppler; (4) grayscale US with addition of 4-μL perflubutane microbubbles (Sonazoid; GE Healthcare Pharma Corporation, Tokyo Japan) to the bath every 5 min; and (5) color Doppler with microbubble addition as above. The Aplio i800 (Canon Medical Systems, Tochigi Japan) US system was used with the i8CX1 transducer. RESULTS: Among six subjects with clots, the number of 24-h clots that changed to hypoechoic under each condition was as follows: (1) 0, (2) 3, (3) 5, (4) 6, and (5) 5. For 72-h clots, the number of changes was: (1) 0, (2) 1, (3) 3, (4) 6, and (5) 3. In Masson's trichrome-stained specimens, US treatment generated less fibrin within the light-blue amorphous element than in the control. No rupture of red blood cells was observed. CONCLUSION: We confirmed that standard clinical diagnostic US, used for grayscale or color Doppler imaging, enhanced thrombolysis. Thrombolytic efficacy was greater with combination of Sonazoid and US than with US alone.
PURPOSE: Ultrasound imaging has been routinely used for needle guidance due to its real-time capability and cost-efficiency. However, conventional ultrasound with fixed-angle transmission often suffers from reduced visua...PURPOSE: Ultrasound imaging has been routinely used for needle guidance due to its real-time capability and cost-efficiency. However, conventional ultrasound with fixed-angle transmission often suffers from reduced visualization of oblique needles when the specular echoes are reflected away from the receiving transducer. METHODS: Synthetic transmit aperture (STA) beamforming with delay and standard deviation (DASD) relies on the variation of echo magnitude among various incident angles to construct the image. It can be further integrated with the specular information of the needle shaft predicted by convolutional neural networks (CNN) models to improve the image contrast in needle detection. The proposed SpecularNet estimates the orientation and the specular probability of the needle from pixel-wise STA channel data. RESULTS: The proposed specular STA-DASD was validated using experiments. Results indicated that, for needle orientations between 10° and 40°, the specular STA-DASD improved the needle-to-speckle ratio (NSR) by 11.0 dB and the needle-to-artifact ratio (NAR) by 18.9 dB compared to the conventional STA-DASD. Compared to standard specular beamforming, the inference to specular information can be efficiently performed in SpecularNet, while both the NSR and NAR of the corresponding specular STA-DASD also improve by another 25-30 dB. CONCLUSION: The efficacy of the proposed specular STA-DASD beamforming was demonstrated for enhancement of needle visualization. The specular information could be predicted using SpecularNet with high computational efficiency to guide the transmit/receive apodization and to suppress background noise and artifacts using image weighting.
Pooh RK, Machida M, Uenishi K
… +11 more, Miyake T, Hata T, Sugiyama R, Shiotani M, Furui K, Mukaida T, Yoshida A, Koga F, Nabeta M, Kyono K, Morimoto Y
J Med Ultrason (2001)
· 2026 Mar · PMID 41886213
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PURPOSE: Accurate crown-rump length (CRL) measurement is fundamental for pregnancy dating and first-trimester screening. The Japanese standards established in 2003 using two-dimensional (2D) ultrasound require updating w...PURPOSE: Accurate crown-rump length (CRL) measurement is fundamental for pregnancy dating and first-trimester screening. The Japanese standards established in 2003 using two-dimensional (2D) ultrasound require updating with modern imaging technology. This study aimed to establish new CRL reference standards for Japanese fetuses using three-dimensional (3D) ultrasound in precisely dated assisted reproductive technology (ART) pregnancies. METHODS: We conducted a multicenter retrospective cohort study of singleton ART pregnancies from 11 Japanese fertility centers (2020-2023), with pregnancy outcomes documented in 2024. Inclusion required term delivery (≥ 37 weeks) and birth weight within the mean ± 1.5 SD. CRL measurements were performed centrally using standardized 3D ultrasound protocols. Polynomial regression models were used to generate reference equations. RESULTS: Of 2,356 datasets, 1,598 pregnancies met inclusion criteria. The mean maternal age was 36.3 ± 4.2 years. Reproducibility was excellent [intra- and inter-observer intraclass correlation coefficients (ICC) > 0.990]. No significant differences were found among ART methods in maternal age, gestational age at delivery, birth weight, or CRL growth pattern (p > 0.01). Third-degree polynomial regression produced reference curves for the 10th, 50th, and 90th percentiles. Compared with 2003 standards, CRL values were consistently larger (p < 0.001), and the growth trajectory showed no significant difference from the INTERGROWTH-21st international curve. Birth weights aligned with national standards, supporting general applicability. CONCLUSION: These updated 3D ultrasound-based CRL reference standards for ART pregnancies modernize Japanese practice and establish a refined framework for accurate gestational dating and first-trimester screening.
Yamakawa M, Shiina T, Ito T
… +8 more, Akashi ST, Murakami K, Watanabe T, Morishima H, Tsugawa K, Uematsu T, Nishida N, Kudo M
J Med Ultrason (2001)
· 2026 Mar · PMID 41886212
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PURPOSE: In recent years, much research has been conducted on ultrasound diagnosis of breast tumors using convolutional neural networks (CNNs). While many CNNs for breast tumor classification have been investigated, prev...PURPOSE: In recent years, much research has been conducted on ultrasound diagnosis of breast tumors using convolutional neural networks (CNNs). While many CNNs for breast tumor classification have been investigated, previous studies have evaluated them using data from the same institution that provided the CNN training data. This may have biased the accuracy of the CNNs. To perform a fairer evaluation, we compared the accuracy of CNNs with that of human experts using a multicenter external validation cohort. Additionally, previous studies used fewer than about 2000 images to train CNNs, whereas this study used 16,530 images. METHODS: We trained a 2-class (benign, malignant) classification CNN and a 4-class (breast cancer, fibroadenoma, simple cyst, and other benign tumors) classification CNN using 16,530 images. Using data from a multicenter external validation cohort, we compared the classification accuracy of the developed CNNs to that of human experts. RESULTS: The 2-class classification CNN achieved an accuracy of 88.1%. The benign/malignant classification from the 4-class classification CNN achieved an accuracy of 86.3%. Human experts achieved an accuracy of 83.2%. Thus, the 2-class classification CNN was slightly more accurate than the benign/malignant classification from the 4-class classification CNN. Both developed CNNs were more accurate than human experts. CONCLUSION: The CNNs developed using a large-scale breast ultrasound image database achieved higher accuracy than that of human experts in evaluation using multicenter external validation cohort data.
Tsutsumi K, Yamamoto K, Oie Y
… +7 more, Miyachi T, Kato Y, Yamao K, Ishikawa T, Ishizu Y, Honda T, Kawashima H
J Med Ultrason (2001)
· 2026 Mar · PMID 41876810
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PURPOSE: Stereotactic body radiation therapy (SBRT) is effective for hepatocellular carcinoma (HCC), and accurate fiducial marker placement is essential for motion-compensated tracking. We assessed the targeting accuracy...PURPOSE: Stereotactic body radiation therapy (SBRT) is effective for hepatocellular carcinoma (HCC), and accurate fiducial marker placement is essential for motion-compensated tracking. We assessed the targeting accuracy and safety achieved with magnetic resonance imaging-ultrasound (MRI-US) fusion guidance and explored factors associated with placement error. METHODS: In this single-center cohort, 44 patients with HCC underwent SBRT with percutaneous fiducial placement under Gd-EOB-DTPA-enhanced MRI-US fusion. A region of interest (ROI) adjacent to the tumor was defined during planning, and the distance difference |A-B| between the planned tumor-ROI distance (A) and the post-procedure tumor-marker distance (B) was used as the targeting error. Predictors of error > 5 mm were explored using a random-forest model. RESULTS: Median targeting error was 6.79 mm (range: 4.06-13.19 mm). In the exploratory model, a longer ROI-tumor distance appeared to have relatively higher feature-importance values for errors > 5 mm, whereas tumor depth and sonographic visibility contributed minimally. During follow-up, four local recurrences and twenty intrahepatic metastases occurred. The cumulative incidence of intrahepatic metastasis was 14.2%, 16.7%, and 24.1% at 180, 360, and 540 days, respectively. Two patients (7.4%) progressed from Child-Pugh class A to B at 6 months. CONCLUSIONS: MRI-US fusion guidance enabled sub-centimeter fiducial placement accuracy in this cohort. A shorter tumor-ROI distance may be associated with smaller targeting error, although this remains exploratory. Tumor depth and visibility showed limited influence on placement accuracy.
Yonehara K, Takigiku K, Tanaka N
… +5 more, Numata R, Shibuya Y, Obinata H, Akazawa Y, Takei K
J Med Ultrason (2001)
· 2026 Mar · PMID 41854925
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PURPOSE: This study aimed to evaluate the impact of sample volume position on fetal cardiac output (CO) measurements. METHODS: Fetuses with normal hearts were enrolled. Fetal CO was calculated using the pulsed Doppler me...PURPOSE: This study aimed to evaluate the impact of sample volume position on fetal cardiac output (CO) measurements. METHODS: Fetuses with normal hearts were enrolled. Fetal CO was calculated using the pulsed Doppler method, with the velocity time integral (VTI) recorded at two distinct positions: the valve hinge level (Valve: V group) and just distal to the valve (Supra-valve: S group). Additionally, we acquired electronic spatio-temporal image correlation (eSTIC) volume data. Left-ventricular CO was calculated as the product of stroke volume and heart rate, with stroke volume derived from left-ventricular volume measurements using the virtual organ computer-aided analysis (VOCAL) technique on the three-dimensional eSTIC data (eSTIC group). We then compared the left-ventricular CO levels among the V, S, and eSTIC groups to assess their correlation. RESULTS: The S group showed significantly larger VTI of the aortic valve (8.5 ± 2.3 vs. 9.3 ± 2.5 cm, V vs. S group). Similarly, the S group also had significantly larger VTI of the pulmonary valve (7.0 ± 1.9 vs. 8.2 ± 2.2 cm). Combined cardiac output (CCO) in the V group was 396 ± 136 mL/min/kg, and that in the S group was 450 ± 154 mL/kg/min, which also showed that the S group had a significantly larger CCO. Focusing on left ventricle CO, the V group was 140 ± 73 mL/kg/min, the S group was 157 ± 77 mL/kg/min, and the eSTIC group was 133 ± 69 mL/kg/min. This suggested that the V group's results were more similar to the eSTIC group's. CONCLUSION: This study suggests that CO measurements are significantly influenced by the sample volume position. Furthermore, placing the VTI sample volume on the valve hinge level appears to reflect CO more accurately.
Takahashi C, Kimura Y, Nishiyama S
… +6 more, Kurosu Y, Ejiri H, Asano M, Suzuki S, Suzuki S, Shimura H
J Med Ultrason (2001)
· 2026 Feb · PMID 41712173
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PURPOSE: The study explored the quantitative analysis of portable ultrasound devices using target images from Multipurpose Phantom N-365. It focused on identifying inter-device variability and time-dependent degradation...PURPOSE: The study explored the quantitative analysis of portable ultrasound devices using target images from Multipurpose Phantom N-365. It focused on identifying inter-device variability and time-dependent degradation of the devices and their probes to support standardization and quality control of ultrasound devices. METHODS: Three ultrasound device models were assessed, with two different setup conditions for each model. Three types of phantom targets, i.e., cyst-like, colloid cyst-like, and nodule-like, were collected from circular grayscale targets. The mean and standard deviation (SD) of brightness were calculated for each target type. RESULTS: Quantification of the mean and SD values of target brightness effectively distinguished between ultrasound devices due to the aging of the ultrasound equipment. Multivariate analysis further revealed that both the probes and the main unit independently contributed to time-related changes. CONCLUSION: This article presents a novel method for ensuring rigorous quality control and promoting standardization in ultrasound examinations by quantifying phantom image characteristics.
Nakajima K, Kamiyama N, Sugimoto K
… +2 more, Hashimoto H, Itoi T
J Med Ultrason (2001)
· 2026 Jan · PMID 41610000
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PURPOSE: Sonazoid contrast-enhanced ultrasound (CEUS) offers valuable diagnostic information on hepatic lesions, but it is time-consuming. In this study, we investigated a novel composite machine-learning framework that...PURPOSE: Sonazoid contrast-enhanced ultrasound (CEUS) offers valuable diagnostic information on hepatic lesions, but it is time-consuming. In this study, we investigated a novel composite machine-learning framework that integrates heuristic knowledge and model-specific classification to differentiate liver lesions using only the first 2 min of CEUS imaging. METHODS: CEUS images from 232 patients with 232 focal liver lesions (benign: 61, hepatocellular carcinoma [HCC]: 104, non-HCC malignancies [ML]: 67) were analyzed. For each case, six frames from injection to peak enhancement and static images at 1 and 2 min post-injection were used. Two deep learning models were developed: Model 1 classified heterogeneous enhancement patterns into "benign," "HCC," "ML," or "Uniform" (homogeneous). Model 2 further classified "Uniform" cases into three diagnostic categories. Lesion brightness values were incorporated as input features. The artificial intelligence (AI) mode was also evaluated by observer study of three hepatologists using the area under the receiver operating characteristic curve (AUC). RESULTS: The composite model was evaluated on 58 independent test cases, achieving classification accuracy of 81.8% for benign, 93.5% for HCC, and 68.8% for ML, with an overall accuracy of 84.5%. Binary classification (benign vs. malignant) yielded 97.9% sensitivity, 94.8% specificity, and 94.8% overall accuracy. For discrimination between benign and malignant, the mean AUC for the three observers was significantly improved with AI output, where the difference in AUC (95% confidence interval) was 0.095 (0.0197, 0.1703) (P = 0.013). CONCLUSIONS: The proposed AI-based framework enables accurate liver lesion classification using early phase CEUS, eliminating the need for Kupffer-phase imaging in many cases.
J Med Ultrason (2001)
· 2026 Jan · PMID 41606354
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Magnetic resonance imaging (MRI)-guided focused ultrasound (MRg-FUS) represents a transformative advancement in functional neurosurgery, providing a minimally invasive and highly precise treatment modality for neurologic...Magnetic resonance imaging (MRI)-guided focused ultrasound (MRg-FUS) represents a transformative advancement in functional neurosurgery, providing a minimally invasive and highly precise treatment modality for neurological disorders, including essential tremor, Parkinson's disease, and dystonia. In Japan, clinical studies investigating its use for essential tremor began in May 2013. This technique employs 1024 ultrasound elements to focus acoustic energy at a fixed intracranial point, generating sufficient heat to induce tissue coagulation while preserving adjacent structures. Real-time MRI provides continuous temperature and positional feedback, ensuring accurate targeting and mitigating the challenges associated with skull density and anatomical variability. Despite these advancements, challenges persist, particularly among Japanese patients, where reduced skull permeability can impede consistent treatment outcomes. Additionally, the requirement for scalp shaving poses considerable esthetic concerns. These factors emphasize the need for continued collaboration between clinical medicine and medical engineering to enhance skull permeability and address cosmetic considerations. MRg-FUS eliminates the need for radiation exposure, incisions, or craniotomy, offering immediate therapeutic benefits with a lower risk profile. Recent technological advancements, including software-driven skull compensation and real-time feedback mechanisms, have improved its safety and efficacy. While limitations, such as skull density variability and incomplete thermal control, remain, ongoing innovations hold promise for expanding its applications, including blood-brain barrier modulation and the treatment of complex neurological disorders. MRg-FUS signifies a paradigm shift toward less invasive, image-guided therapies in contemporary neurosurgery.
Tanaka S, Ohba N, Saito N
… +7 more, Tanaka K, Ishimoto Y, Ochi K, Yasui K, Fujita M, Abe K, Takahashi S
J Med Ultrason (2001)
· 2026 Jan · PMID 41604121
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PURPOSE: Attenuation techniques have been developed to quantify liver fat, improving diagnostic accuracy. However, the standardization of measurement methods remains undefined, limiting clinical application. This study e...PURPOSE: Attenuation techniques have been developed to quantify liver fat, improving diagnostic accuracy. However, the standardization of measurement methods remains undefined, limiting clinical application. This study evaluated the effect of different region of interest (ROI) settings on the attenuation coefficient (AC) and coefficient of determination (R) in attenuation imaging (ATI). METHODS: We analyzed 5212 ultrasound examinations performed at our institution. Two periods were compared: early [ROI positioned at twice the subcutaneous thickness; double positioning (DP), 2 × 3 cm] and late [ROI placed beneath the multireflection layer; color positioning (CP), 2 × 4 cm]. Additionally, AC and R were analyzed in 331 patients with stored raw data across four conditions: DP and CP for positioning, and 2 × 3 cm and 2 × 4 cm for size, respectively, using Bland-Altman analysis. RESULTS: The early and late periods included 2881 and 2331 examinations, respectively. Patient characteristics were comparable. Significant differences were observed in the AC (median, 0.58 vs. 0.56 dB/cm/MHz), steatotic liver diagnostic rates based on AC, R (median, 0.87 vs. 0.93), and proportion of R ≥ 0.90. Raw data analysis showed slight differences in AC and R according to ROI position; however, there were significant differences in ROI size (AC: 2 × 3 > 2 × 4; R: 2 × 4 > 2 × 3). CONCLUSION: In ATI, the larger ROI improved R, whereas the smaller ROI yielded higher AC values, suggesting that ROI size affects diagnostic reliability. Standardizing ATI protocols is essential, with uniformity in ROI size being a priority.
Ishida A, Onoue S, Ikuta Y
… +10 more, Tashiro T, Arima S, Komiya M, Mizuta R, Ishihara H, Kobayashi T, Gao F, Brand A, Yamada T, Maeda N
J Med Ultrason (2001)
· 2026 Jan · PMID 41579262
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PURPOSE: To evaluate the dynamics of the talus-lateral malleolus distance during landing and compare the results between individuals with chronic ankle instability (CAI) and healthy adults. METHODS: Participants were div...PURPOSE: To evaluate the dynamics of the talus-lateral malleolus distance during landing and compare the results between individuals with chronic ankle instability (CAI) and healthy adults. METHODS: Participants were divided into the healthy (12 adults, 12 feet) and CAI (12 adults, 12 feet) groups. Participants performed forward single-leg drop landing from a 30-cm-high box. Through the synchronization of ultrasound with a motion capture system, measurements of the talus-lateral malleolus distance and ankle joint angles were obtained during forward single-leg drop landing. The analysis interval was from 200 ms before to 200 ms after initial contact; the time was normalized to 100%. Statistical parametric mapping was employed to investigate differences in the temporal changes of the talus-lateral malleolus distances and ankle joint angles during landing between groups. RESULTS: A significantly longer talus-lateral malleolus distance was observed before initial contact in the CAI group (1-49%) as compared with the healthy group (p = 0.000). In addition, the ankle adduction angle before initial contact (12-61%) was larger in the CAI group than in the healthy group (p = 0.005). CONCLUSION: Our findings suggest that the talus-lateral malleolus distance increases along with the ankle adduction movement in individuals with CAI, especially before initial contact, potentially indicating high mechanical ankle instability. This study established an innovative measurement system for quantitative evaluation of the dynamics of the talus and lateral malleolus during landing. The findings of this study may contribute to a more detailed understanding of pathology and features of movement in patients with CAI.