Satoru Morita

We report a case of idiopathic chyluria in a woman in her 70s, successfully treated by direct percutaneous puncture and embolization of the fistula site. The patient had experienced persistent milky-white urine, progressive weight loss, and voiding difficulties for >3 years. Inguinal intranodal lymphangiography identified a lymphatic-urinary fistula near the lower pole of the left renal calyx. Later, under fluoroscopic guidance, the fistula site was directly punctured and embolized using n-butyl cyanoacrylate without complications. Her symptoms resolved immediately, and there has been no recurrence over a two-year follow-up period while she remained on a regular diet. This case highlights the effectiveness of direct percutaneous embolization of the fistula site as a minimally invasive treatment option for refractory chyluria.

Objective: This study aims to clarify the frequency of renal parenchymal defects and deformations in each subtype of perirenal liposarcomas and to compare the differences between well-differentiated and non–well-differentiated types. Methods: Patients with perirenal liposarcomas seen between July 2004 and June 2024 were included. Two radiologists blinded to the subtypes retrospectively evaluated CT or MR images for renal parenchymal defects and deformations. Frequencies of these findings were compared between well-differentiated versus non–well-differentiated types using the Fisher test. Results: Forty-two patients (mean age: 66.3±11.5 y; 15 men) with perirenal liposarcomas were included. Renal parenchymal defects and deformations were observed in 0 (0%) and 1 (7.7%) of 13 well-differentiated, 5 (29.4%) and 6 (35.3%) of 17 dedifferentiated, 3 (37.5%) and 0 (0%) of 8 myxoid, and 1 (25.0%) and 1 (25.0%) of 4 pleomorphic types, respectively. Non–well-differentiated liposarcomas had higher frequencies of renal parenchymal defects and deformations compared with well-differentiated liposarcomas [9 of 29 (31.0%) vs. 0 of 13 (0%), P =0.038 and 7 of 29 (24.1%) vs. 1 of 13 (7.7%), P =0.398]. Conclusion: Renal parenchymal defects can be occasionally observed (31.0%) in non–well-differentiated perirenal liposarcomas unlike well-differentiated liposarcomas.

Objective: Radiographic findings to identify central venous catheter misplacement in the arteries, which can cause lethal complications, have not been fully evaluated, and its training is difficult because it is rare. The purpose of this study is to clarify radiographic findings for differentiating central venous and misplaced arterial lines using virtual chest radiographs and elucidate their usefulness in training radiologists. Methods: This retrospective study included 150 patients (mean age, 67 [SD, ±12] years; 97 men) who underwent colon cancer surgery between January 2018 and December 2020. Virtual chest radiographs, including 6 oblique projections at 5° intervals, were developed from the computed tomography images using ray-sum reconstruction. Virtual venous and arterial lines were drawn from the right neck to the superior vena cava and aorta, respectively. Diagnostic abilities, including area under the curve (AUC) analysis of the 7 proposed radiographic findings for differentiating these lines in 100 patients, were evaluated. The diagnostic performance, including AUC analysis by 5 radiologists in the other 50 patients, was compared before and after disclosing these results to the radiologists. Results: The findings of crossing over the right paratracheal stripe and running along the paracaval line showed the highest AUC for indicating arterial and venous lines in the frontal, right anterior oblique 15°, and left anterior oblique 15° projections (AUC = 0.992, 0.991, and 0.979, and 1.000, 0.994, and 0.998, respectively). The diagnostic performance of the radiologists improved after informing them of these results (AUC, 0.982–0.999 to 0.993–1.000 [P = 0.145–1.000] for the frontal projections and 0.932–0.970 to 0.967–0.995 [P = 0.075–0.150] for the oblique projections). Conclusions: Virtual chest radiographs created from computed tomography images were useful for clarifying radiographic findings for differentiating central venous and misplaced arterial lines and for training radiologists.

Aim: The unique feature of Fontan circulation is elevated central venous pressure, which causes Fontan‐associated liver disease (FALD). FALD is associated with a high incidence of hepatocellular carcinoma (HCC). Performing biopsies in patients with FALD is difficult as a result of warfarinization; gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI), a noninvasive examination, is useful for characterizing liver disease and detecting HCC. However, few studies have reported the detailed features of Gd‐EOB‐DTPA MRI, and the association between these findings and prognosis. Thus, this study aimed to investigate the utility of Gd‐EOB‐DTPA MRI to predict HCC development in patients with FALD.Methods: This study enrolled 44 patients with FALD (mean age 25 years) who underwent Gd‐EOB‐DTPA MRI. The hepatobiliary phase images were scored semiqualitatively, and the patients were classified into the mild (0–1 point) or severe group (≥2 points). The endpoint was HCC, and event‐free survival was analyzed using Kaplan–Meier and log‐rank tests.Results: The severe group included 19 patients. During a mean follow‐up of 58 months, HCC developed in six patients. Kaplan–Meier analysis revealed that patients in the severe group had a significantly poorer prognosis than those in the mild group (p = 0.0053). The Fibrosis‐4 index and liver‐to‐spleen ratio of patients with HCC were moderate.Conclusions: Gd‐EOB‐DTPA MRI can be used to classify disease severity and predict the prognosis of patients with FALD.

Purpose To evaluate the accuracy of needle placement using a three-dimensional (3D) augmented reality (AR) protractor on smartphones (AR Puncture). Materials and Methods An AR protractor that can be rotated in three directions against the CT plane with angle guidance lines for smartphones was developed. The protractor center can be adjusted to an entry point by manually moving the smartphone with the protractor center fixed at the center of the screen (Fix-On-Screen) or by image tracking with a printed QR code placed at an entry point (QR-Tracking). Needle placement was performed by viewing a target line in the tangent direction with the Bull’s eye method. The needle placement errors placed by four operators in six out-of-plane directions in a phantom using a smartphone (iPhone XR, Apple, Cupertino, CA, USA) were compared with two registration methods. Results No significant difference in the average needle placement error was observed between the Fix-On-Screen and QR-Tracking methods (5.6 ± 1.7 mm vs. 6.1 ± 2.9 mm, p = 0.475). The average procedural time of the Fix-On-Screen method was shorter than that of the QR-Tracking method (71.0 ± 23.9 s vs. 98.4 ± 59.5 s, p = 0.042). Conclusion The accuracies of out-of-plane needle placements using the 3D AR protractor with the two registration methods were equally high, with short procedure times. In clinical use, the Fix-On-Screen registration method would be more convenient because no additional markers are required.

Purpose To develop and assess the accuracy of a mixed reality (MR) needle guidance application on smartglasses. Materials and Methods An MR needle guidance application on HoloLens2, without pre-procedural CT image reconstruction or import by manually matching the spatial and MR coordinate systems, was developed. First, the accuracy of the target locations in the image overlay at 63 points arranged on a 45 × 35 × 21 cm box and needle angles from 0° to 80°, placed using the MR application, was verified. The needle placement errors from 12 different entry points in a phantom by seven operators (four physicians and three non-physicians) were compared using a linear mixed model between the MR guidance and conventional methods using protractors. Results The average errors of the target locations and needle angles placed using the MR application were 5.9 ± 2.6 mm and 2.3 ± 1.7°, respectively. The average needle insertion error using the MR guidance was slightly smaller compared to that using the conventional method (8.4 ± 4.0 mm vs. 9.6 ± 5.1 mm, p = 0.091), particularly in the out-of-plane approach (9.6 ± 3.5 mm vs. 12.3 ± 4.6 mm, p = 0.003). The procedural time was longer with MR guidance than with the conventional method (412 ± 134 s vs. 219 ± 66 s, p < 0.001). Conclusion MR needle guidance without pre-procedural CT image import is feasible when matching coordinate systems, and the accuracy of needle insertion is slightly better than that of the conventional method.

Objectives To retrospectively evaluate whether the early dark cortical band (EDCB) on CT can be a predictor to differentiate clear cell renal cell carcinoma (ccRCC) from fat poor angiomyolipoma (Fp-AML) and to detect peritumoral pseudocapsules in ccRCC. Methods The EDCBs, which are comprised of unenhanced thin lines at the tumor-renal cortex border in the corticomedullary phase, on the CT images of 342 patients who underwent partial nephrectomy were evaluated. Independent predictors among the clinical and CT findings for differentiating ccRCC from Fp-AML were identified using multivariate analyses. The diagnostic performance of the EDCB for diagnosing peritumoral pseudocapsule in ccRCC and differentiating ccRCC from Fp-AML was calculated. Results The EDCB was observed in 157 of 254 (61.8%) ccRCCs, 4 of 31 (12.9%) chromophobe RCCs, 1 of 21 (4.8%) papillary RCCs, 3 of 11 (27.3%) clear cell papillary RCCs, 3 of 8 (37.5%) oncocytomas, and 0 of 17 (0%) Fp-AMLs. There was substantial interobserver agreement for the EDCB (k = 0.719). The EDCB was a significant predictor for differentiating ccRCC from Fp-AML (p < 0.001). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of the EDCB for differentiating ccRCC from Fp-AML were 61.8%, 100%, 100%, and 14.9%, respectively, and those for detecting pseudocapsule in 236 ccRCCs were 62.3%, 68.8%, 96.5%, and 11.7%, respectively. Conclusion Although diagnostic accuracy of the EDCB for detecting peritumoral pseudocapsule in RCC is inadequate, it can be a predictor for differentiating ccRCC from Fp-AML with high specificity and PPV. Key Points • The early dark cortical band (EDCB) sign is observed in nearly two-thirds of clear cell renal cell carcinoma (ccRCC) that are treated by partial nephrectomy and have substantial interobserver agreement. • The EDCB is a significant predictor for differentiating ccRCCs from fat poor angiomyolipomas, with a high specificity and positive predictive value. • Diagnostic accuracy of the EDCB for detecting peritumoral pseudocapsule in ccRCC is inadequate, though better than those in the nephrographic and excretory-phase images.

Purpose: To retrospectively evaluate the mid-term outcome of transarterial embolization (TAE) of renal artery pseudoaneurysm (RAP) including arteriovenous fistula (AVF) after partial nephrectomy screened by early postoperative contrast-enhanced CT (CE-CT). Materials and methods: Eighty-two patients (7.0%) who underwent TAE after partial nephrectomy were reviewed, from 1166 partial nephrectomies performed over 6 years. In 18 patients (22.0%), TAE was performed emergently on the median postoperative day (POD) seven. In the remaining patients, elective TAE was performed on the median POD six for RAP detected by early postoperative CE-CT or that emerged on follow-up CE-CT. Results: In one patient (1.2%), TAE was performed twice because one of two RAPs could not be embolized during the first TAE, being successfully embolized at the second TAE after readmission with hematuria. Otherwise, no bleeding recurrence or RAPs were observed during the median 1354 follow-up days. Thus, the primary and secondary success rates of TAE were 98.8% (81 of 82 patients) and 100% (82 of 82 patients), respectively. On angiography, the average number of lesions was 1.7 ± 0.9 and the average RAP size was 12.8 ± 6.0 mm. The shapes of the lesions varied: oval-round 60, oval-round + AVF 36, irregular + AVF 14, AVF 12, irregular 10, disruption 4, and extravasation 3. No major complications were observed. The median inpatient days after TAE were two. No estimated glomerular filtration rate deterioration was observed (64.6 ± 18.6 vs. 64.2 ± 18.4 mL/min/1.73 m², p = 0.902). Conclusion: TAE is largely effective and safe for treating bleedings or RAPs, including AVFs, after partial nephrectomy, as screened by early postoperative CE-CT.

Purpose To assess the safety and feasibility of unilateral double femoral venous access including double sheath insertion via a single-hole method (two-in-one method) for adrenal venous sampling (AVS). Materials and methods Two 5-Fr sheaths were percutaneously inserted into a single femoral vein for AVS in 324 patients. Two needles were inserted sequentially in tandem under ultrasound guidance; furthermore, two sheaths were individually inserted (two-in-two method) if both punctures were successfully achieved. In the presence of a single puncture, two sheaths were inserted through two guidewires and a temporarily inserted sheath (two-in-one method). This protocol was repeated until two sheaths were successfully inserted. Thus, two sheaths were inserted with the two-in-one method in 56 patients (17.3%) and two-in-two method in 268 patients (82.7%). Results No significant differences in the technical success rates of AVS were observed (p = 0.067–0.647). Minor groin hematoma was observed more frequently in the two-in-one than in the two-in-two method (8.9% vs. 2.6%, p = 0.039). No major groin hematoma, deep venous thrombosis, or pulmonary embolization was observed. The mean number of needle puncture was 2.5 ± 1.3 and duration of inserting two sheaths 5.1 ± 3.9 min. Conclusion Unilateral double femoral venous access including the two-in-one method is safe and feasible for AVS.