Published papers

Background: Vessels encapsulating tumor clusters (VETC) pattern is tumor vasculature of HCC and is a predictor of prognosis and therapeutic efficacy. Recent radiological studies have demonstrated the predictability of VETC from preoperative images, but the mechanisms of image formation are not elucidated. This study aims to determine the relationship between VETC and intratumor heterogeneity in Gd-EOB-DTPA-enhanced magnetic resonance imaging (EOB-MRI) and to provide its pathological evidence. Methods: Radiologists visually classified preoperative arterial- and hepatobiliary-phase EOB-MRI images of 204 surgically resected HCCs into patterns based on heterogeneity and signal intensity; these classifications were validated using texture analysis. Single and multiplex immunohistochemistry for CD34, h-caldesmon, and OATP1B3 were performed to evaluate VETC, arterial vessel density (AVD), and OATP1B3 expression. Recurrence-free survival was assessed using the generalized Wilcoxon test. The contribution of clinicoradiological factors to the prediction of VETC was evaluated by random forest and least absolute shrinkage and selection operator regression. Results: VETC was frequently found in tumors with arterial-phase heterogeneous hyper-enhancement patterns and in tumors with hepatobiliary-phase heterogeneous hyperintense/isointense patterns (HBP-Hetero). AVD and OATP1B3 expression positively correlated with signal intensity in the arterial and hepatobiliary phases, respectively. Intratumor spatial analysis revealed that AVD and OATP1B3 expression were lower in VETC regions than in tumor regions without VETC. Patients with HBP-Hetero tumors had shorter recurrence-free survival. Machine learning models highlighted the importance of serum PIVKA-II, tumor size, and enhancement pattern of arterial and hepatobiliary phase for VETC prediction. Conclusions: VETC is associated with local reductions of both AVD and OATP1B3 expression, likely contributing to heterogeneous enhancement patterns in EOB-MRI. Evaluation of the arterial and hepatobiliary phases of EOB-MRI would enhance the predictability of VETC.

Purpose: MR cholangiopancreatography (MRCP) often suffers from signal loss because of concentrated bile. Gradient-and-spin-echo (GRASE) MRCP reduces this effect but is limited by breath-holding. We developed MRCP with centric order encoding (MRCP-CORE), a novel free-breathing sequence with shorter TE using centric k-space trajectory, T2 preparation, and velocity encoding, and evaluated its ability to visualize gallbladder.Methods: In this prospective, single-center study, we enrolled 100 consecutive patients who underwent 3 MRCP sequences (MRCP-CORE, conventional MRCP, and GRASE MRCP) on a 3T system. Two blinded radiologists independently assessed the visibility of anatomical structures, artifacts, and overall image quality. SNR, contrast-to-noise ratio, and contrast ratio of the periductal tissue and gallbladder were measured. The Friedman test was used for comparisons; Jonckheere–Terpstra analysis tested the association between the gallbladder visibility and quantitative metrics.Results: Ninety-nine patients (mean age, 68.5 ± 10.9 years; 52 men, 47 women) were evaluated. MRCP-CORE showed significantly higher SNR than conventional and GRASE MRCP (20.9 vs. 17.3 vs. 15.8; P < 0.001). Gallbladder visibility was significantly higher with MRCP-CORE than via conventional MRCP (P = 0.02) and comparable to that via GRASE MRCP (P = 1.00). No significant differences in artifact and overall image quality were observed among sequences. Trend analysis revealed gallbladder visibility was significantly influenced by bile concentration in conventional MRCP (P < 0.001), but not in MRCP-CORE (P = 0.12) or GRASE MRCP (P = 0.43).Conclusion: MRCP-CORE enhanced gallbladder depiction compared with conventional MRCP, offering a robust free-breathing alternative to breath-hold GRASE MRCP.

Aim: Among mass-forming (MF) type intrahepatic cholangiocarcinoma (ICC), approximately 20%–30% are hypervascular on imaging and are associated with improved prognosis. However, the molecular background based on gene expression of this entity remains unclear. Methods: We retrospectively analyzed 109 patients with MF-type ICC resected at the National Cancer Center Hospital, Japan. Preoperative dynamic computed tomography (CT) images were available for 48 cases. Based on the late-arterial-phase enhancement area (EA) and the relative enhancement ratio (RER), 17 were classified as hypervascular ICC (H-ICC, EA ≥ 50%), 21 as hypovascular ICC (h-ICC, EA < 50%, RER ≥ 1), and 10 as nonvascular ICC (N-ICC, EA < 50%, RER < 1). We compared group-wise arterial vessel density (AVD), then profiled angiogenesis genes to identify a suitable immunohistochemical marker. Results: The H-ICC group had a better prognosis than h-ICC (P = 0.024) and N-ICC (P = 0.002). H-ICC also had a higher AVD than other groups (P < 0.001). Among the angiogenesis-related genes, vascular endothelial growth factor A (VEGFA) exhibited the strongest correlation with EA (P = 0.012), and H-ICC exhibited higher VEGF positivity than other groups (P = 0.022). The survival and immunostaining profiles of h-ICC closely resembled those of N-ICC. ROC analysis revealed that a VEGF staining positivity of 70% was the optimal cut-off for identifying H-ICC. Conclusions: H-ICC is characterized by hyperenhancement occupying ≥ 50% of the tumor area on dynamic CT, high AVD, and elevated VEGFA expression. These findings support a distinct clinicopathological subset identifiable by LAP enhancement and VEGF immunostaining.

A dual imaging pattern of hyperattenuation on non-enhanced computed tomography and hypointensity on T2-weighted imaging is frequently encountered in various lesions. In the present review, we aimed to explore this imaging combination across a spectrum of abdominal and pelvic lesions to clarify its clinical implications.This pattern is commonly observed in lesions rich in fibrous or smooth muscle components, making it more frequently encountered in benign entities, including fat-poor angiomyolipomas, uterine leiomyomas, and tumors with predominant fibrous stroma. However, similar imaging findings may also be encountered in rare high-cellularity malignancies, selected systemic diseases, and lesions containing melanin, metal deposition, or thyroid tissue. Although not specific to a single disease, this imaging pattern offers valuable diagnostic clues for lesion characterization. When contrast-enhanced imaging is unavailable or contraindicated, combining non-enhanced computed tomography and T2-weighted imaging findings may help narrow the differential diagnosis. Despite its general association with benign lesions, this imaging phenotype requires careful exclusion of important pathologic mimics. Overall, integration with clinical information and other imaging findings remains essential for accurate interpretation.

Purpose: To evaluate the incidence and clinical course of lower-limb lymphedema following intranodal n-butyl-2-cyanoacrylate (nBCA) embolization of the inguinal lymph nodes for postoperative lymphorrhea. Materials and Methods: This retrospective study included 26 patients (24 men and 2 women; age, 69.5 years) who underwent intranodal nBCA embolization for postoperative lymphorrhea between 2017 and 2023. Under ultrasound (US) guidance, inguinal lymph nodes were punctured, and embolization was performed with nBCA and ethiodized oil at a 2:1 ratio (ethiodized oil:nBCA). The primary approach was to embolize through the initially accessed lymph node when the efferent channel and leakage site were visualized. Clinical success was defined as improvement of lymphorrhea-related symptoms with catheter removal or ≥80% drainage reduction within 21 days. Lower-limb lymphedema was defined as new-onset or worsening of existing edema in 60 days after embolization and categorized as reversible or persistent. Results: Clinical success was achieved in 24 of 26 patients (92.3%), with a median time to resolution of 6 days (range, 2–21 days). Lower-limb lymphedema worsened in 6 patients (23.1%), including 4 reversible and 2 persistent cases. No new-onset lymphedema occurred; all represented exacerbation of pre-existing edema. Both persistent cases involved patients with prior pelvic lymph node dissection. No procedure-related deaths or major complications occurred. Conclusion: Inguinal intranodal nBCA embolization effectively controls postoperative lymphorrhea but may worsen pre-existing lower-limb lymphedema, particularly in patients with prior pelvic lymph node dissection. To minimize nontarget embolization of lower-extremity drainage pathways, lymphatic embolization should be performed as selectively and as close to the leakage site as possible.

＜文献概要＞今回我々は,原発性硬化性胆管炎(primary sclerosing cholangitis:PSC)の経過観察中に胆管内乳頭状腫瘍(intraductal papillary neoplasm of the bile duct:IPNB)を生じ,肝破裂と腹膜播種をきたしたと考えられるまれな症例を経験したので報告する。

This review provides key insights into sacroiliitis imaging, covering anatomy, imaging techniques, and interpretation. It focuses on normal physiological changes in young to middle-aged women, children, and the elderly that can resemble sacroiliitis. We emphasize the importance of distinguishing between active and structural lesions, as highlighted in the recent ASAS-SPARTAN standardized magnetic resonance imaging protocol. Physicians should be aware that bone marrow oedema signals on magnetic resonance imaging, a hallmark of active inflammation in axial spondyloarthritis, can also be observed in young to middle-aged women, especially postpartum, even without spondyloarthritis. Paediatric sacroiliac joints may show changes mimicking inflammation due to ongoing bone growth. Furthermore, degenerative changes in the sacroiliac joint are common with advancing age and can be mistaken for sacroiliitis or interpreted as structural changes. The presence of accessory sacroiliac joints, prone to degeneration, further complicates diagnosis. Accurate interpretation requires considering these normal variations to avoid misdiagnosing spondyloarthritis. Collaboration between clinicians and radiologists is crucial, especially when encountering atypical or clinically inconsistent findings.

PURPOSE: To achieve a historical perspective, the chronological changes in primary liver cancer over a 20-year period were investigated at a single institution, focusing on shifts in etiology and the impact on imaging and pathological findings using The Liver Imaging Reporting and Data System. MATERIALS AND METHODS: A retrospective study of surgically resected primary liver cancer in 680 patients from 2001 to 2020 resulted in 434 patients with 482 nodules being analyzed. Dynamic contrast-enhanced computed tomography imaging and the Liver Imaging Reporting and Data System 2018 classification were employed. Two pathologists and two radiologists independently evaluated specimens and images. RESULTS: This study highlighted a significant decline in cases of viral hepatitis and cirrhosis in primary liver cancer patients but an increase in intrahepatic cholangiocarcinoma and scirrhous hepatocellular carcinoma. Notably, there was a rise in non-viral hepatitis cases, potentially pointing toward an increase in steatohepatitic hepatocellular carcinoma cases in the future. Intrahepatic cholangiocarcinoma, scirrhous hepatocellular carcinoma and steatohepatitic hepatocellular carcinoma tumors exhibited slightly different distributions in the Liver Imaging Reporting and Data System classification compared with ordinary hepatocellular carcinoma, which may reflect the presence of fibrosis and lipid in tumor parenchyma. CONCLUSIONS: Consistent with past reports, this study demonstrated the emergence of primary liver cancer against a backdrop of non-viral and non-cirrhotic liver. Liver Imaging Reporting and Data System has been consistently useful in diagnosing primary liver cancer; however, among the histological subtypes of hepatocellular carcinoma, an increase is anticipated in scirrhous hepatocellular carcinoma and steatohepatitic hepatocellular carcinoma, which may present imaging findings different from those of ordinary hepatocellular carcinoma. This development may necessitate a reevaluation of the current approach for diagnosing and treating hepatocellular carcinoma based solely on imaging.

BACKGROUND: Neoadjuvant therapy is recommended for treating resectable pancreatic ductal adenocarcinoma (PDAC); however, its appropriate use in patients with resectable PDAC remains debatable. OBJECTIVE: This study aimed to identify independent poor prognostic factors and evaluate the clinical significance of neoadjuvant therapy in patients with resectable PDAC. METHODS: We retrospectively reviewed consecutive patients diagnosed with resectable PDAC at our institute between January 2003 and December 2022. We analyzed poor prognostic factors at the time of diagnosis in patients who underwent upfront surgery using the Cox proportional hazards model for overall survival (OS). The prognostic score was calculated by adding the individual prognostic factor scores. RESULTS: Overall, 359 patients were included in this study, with 308 patients undergoing upfront surgery and the remaining 51 patients receiving neoadjuvant therapy. The R0 resection rate was significantly higher in the neoadjuvant therapy group (70.6%) than in the upfront surgery group (64.0%). Multivariate analysis in the upfront surgery group revealed the following independent poor prognostic factors: tumor size ≥ 35 mm, serum albumin level ≤ .5 g/dL, neutrophil-to-lymphocyte ratio ≥ 3.5, carbohydrate antigen 19-9 level ≥ 250 U/mL, and Duke pancreatic monoclonal antigen type 2 level ≥ 750 U/mL. Among patients with prognostic scores of 0-1 (n = 263), the intention-to-treat OS did not significantly differ between the neoadjuvant therapy and upfront surgery groups. Among those patients with a prognostic score of ≥ 2 (n = 96), the neoadjuvant therapy group had significantly longer intention-to-treat OS than the upfront surgery group. CONCLUSIONS: Prognostic score-based stratification can help identify patients who could benefit from neoadjuvant therapy.