Adenoma mimicking intraductal papillary neoplasm of the bile duct arising in an intrahepatic biliary duplication cyst.

We report a case of a cystic liver tumour in a 47-year-old man with Peutz-Jeghers syndrome (PJS) who had undergone sclerotherapy at another hospital for a cyst in hepatic segment IV (S4) 7 years earlier. Based on the preoperative imaging findings, the patient was diagnosed with an intraductal papillary neoplasm of the bile duct. Percutaneous transhepatic portal vein embolization was performed to increase the residual liver volume, followed by resection of the three right hepatic lobes and the caudate lobe, biliary reconstruction, and portal vein reconstruction. Pathological examination revealed an adenoma arising in an intrahepatic biliary duplication cyst. Retrospectively, the preoperative diagnosis was difficult, but it aligned with previous reports of biliary duplication cysts due to its continuity with the bile duct. Additionally, intrahepatic biliary duplication cysts with tumour lesions or cases in which 18F-fluorodeoxyglucose positron emission tomography was performed have not been previously reported. Therefore, preoperatively listing this disease as a differential diagnosis was difficult. PJS and chronic inflammation associated with cyst sclerotherapy may have contributed to tumour development in the intrahepatic biliary duplication cyst.

The effect of hormone therapy on physiological uptake of the endometrium on [18F]F-FDG PET in postmenopausal women.

OBJECTIVE: The effects of hormonal therapy, estrogen-based hormone replacement therapy (HRT), and anti-tumor hormone therapy, such as tamoxifen, on the physiological uptake of the endometrium on 2-deoxy-2[18F]fluoro-D-glucose ([18F]F-FDG) positron emission tomography (PET) in postmenopausal women have not been determined. We explored the effect of hormone therapy, particularly HRT, on physiological uptake in the endometrium of postmenopausal women. MATERIALS AND METHODS: Postmenopausal women receiving hormone therapy who underwent cancer screening using PET/computed tomography (CT) between June 2016 and April 2023 were included in the hormone therapy group (n = 21). Postmenopausal women with no history of hormone therapy were included in the control group (n = 49). First, the physiological endometrial uptake at menopausal age and at least 1 year thereafter was compared quantitatively (SUVmax) and qualitatively (4-point scale) in the control group, to assess when the endometrium ceased to show significant physiological [18F]F-FDG uptake after menopause. Endometrial uptake was compared between the hormone therapy and control groups. The association between HRT duration (months) and endometrial uptake (SUVmax) was evaluated. Endometrial thickness, measured using transvaginal ultrasonography, was also compared between the two groups. RESULTS: Endometrial uptake was significantly reduced both qualitatively and quantitatively (P < 0.05) at least 1 year after menopause in control patients, by which time most women (89.8%) no longer had significant endometrial uptake. The hormone therapy group (n = 21) showed higher FDG uptake in the endometrium compared to the control group (median SUVmax: 2.3 vs 1.9, P = 0.0011), as well as a higher visual score (P < 0.0001). HRT duration did not correlate with endometrial uptake (P = 0.097). Endometrial thickness in the hormone therapy group was significantly thicker than in the control group (median: 3.9 mm vs 1.8 mm, P = 0.002). CONCLUSION: Hormone therapy may affect physiological uptake in the endometrium in postmenopausal women.

SMARCA4-Deficient Poorly Differentiated Adenocarcinoma of the Gallbladder.

ABSTRACT: A 64-year-old woman presented with chest pain while eating and was referred to our hospital. Physical examination revealed abdominal distension, tenderness, and lower-extremity edema. Imaging revealed a large gallbladder tumor infiltrating the liver, with ascites and pleural effusion. A biopsy confirmed a poorly differentiated adenocarcinoma with SMARCA4 deficiency (cT3N2M1, cStage IV). Chemotherapy was ineffective and led to tumor progression. The patient died 9 months later. Recently, attention has been paid to SMARCA4 deficiency, which is a genetic mutation found in tumors. Here, we report on poorly differentiated adenocarcinomas of the gallbladder based on imaging findings, including FDG PET.

Clinical and imaging characteristics of supratentorial glioma with IDH2 mutation.

PURPOSE: The rarity of IDH2 mutations in supratentorial gliomas has led to gaps in understanding their radiological characteristics, potentially resulting in misdiagnosis based solely on negative IDH1 immunohistochemical staining. We aimed to investigate the clinical and imaging characteristics of IDH2-mutant gliomas. METHODS: We analyzed imaging data from adult patients with pathologically confirmed diffuse lower-grade gliomas and known IDH1/2 alteration and 1p/19q codeletion statuses obtained from the records of our institute (January 2011 to August 2022, Cohort 1) and The Cancer Imaging Archive (TCIA, Cohort 2). Two radiologists evaluated clinical information and radiological findings using standardized methods. Furthermore, we compared the data for IDH2-mutant and IDH-wildtype gliomas. Multivariate logistic regression was used to identify the predictors of IDH2 mutation status, and receiver operating characteristic curve analysis was employed to assess the predictive performance of the model. RESULTS: Of the 20 IDH2-mutant supratentorial gliomas, 95% were in the frontal lobes, with 75% classified as oligodendrogliomas. Age and the T2-FLAIR discordance were independent predictors of IDH2 mutations. Receiver operating characteristic curve analysis for the model using age and T2-FLAIR discordance demonstrated a strong potential for discriminating between IDH2-mutant and IDH-wildtype gliomas, with an area under the curve of 0.96 (95% CI, 0.91-0.98, P = .02). CONCLUSION: A high frequency of oligodendrogliomas with 1p/19q codeletion was observed in IDH2-mutated gliomas. Younger age and the presence of the T2-FLAIR discordance were associated with IDH2 mutations and these findings may help with precise diagnoses and treatment decisions in clinical practice.

Spatial Pattern of Intraprostatic Recurrence after Definitive External-Beam Radiation Therapy for Prostate Cancer: Implications for Focal Boost to Intraprostatic Dominant Lesion.

Purpose: We retrospectively investigated spatial pattern associations between primary and recurrent tumor sites after definitive external-beam radiation therapy (EBRT) for prostate cancer, using positron emission tomography/computed tomography (PET/CT) with a prostate-specific membrane antigen (PSMA)-targeted probe, 18F-FSU-880. Methods and Materials: We used data from our prior phase 2 trial involving patients who received PET/CT with 18F-FSU-880, which was designed to evaluate the tumor detection efficacy of PSMA-PET/CT for recurrent prostate cancer. Data from patients with local intraprostatic recurrence detected by PSMA-PET/CT after definitive EBRT were retrospectively analyzed. The prostate and seminal vesicles were divided into 14 sections. Two diagnostic radiologists separately re-evaluated the intraprostatic location of the primary tumor on magnetic-resonance imaging and that of the recurrent tumor on PSMA-PET/CT, respectively, and the rate of overlap between primary and recurrent tumors was calculated. The overlap rate was defined as "the number of sections that overlapped between the primary tumor and recurrent tumor" divided by "the total number of sections of recurrent tumor". A recurrent tumor was considered to be at the same location as the primary tumor when the overlap rate was equal to or greater than 75%, and a partial overlap was defined as an overlap rate between 25 and 74%. Results: Twelve patients had local recurrence detected by PSMA-PET/CT. The median time to diagnosis of local recurrence was 9.1 (range, 2.2-12.3) years after definitive EBRT. The recurrent tumor was detected at the same location in 25.0%, and a partial overlap was noted in 41.7%. Conclusions: Local intraprostatic recurrence after definitive EBRT often occurs at the same site or at a partially overlapping site adjacent to the primary intraprostatic dominant lesion. Our results support the merit of focal dose-escalation for intraprostatic dominant lesions in definitive EBRT.

English version of Japanese Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) issued by the Japan Society of Clinical Oncology.

The Japan Society of Clinical Oncology Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) have been published in accordance with the Minds Manual for Guideline Development 2014 and 2017. A specialized team independent of the working group for the revision performed a systematic review. Since GIST is a rare type of tumor, clinical evidence is not sufficient to answer several clinical and background questions. Thus, in these guidelines, we considered that consensus among the experts who manage GIST, the balance between benefits and harms, patients' wishes, medical economic perspective, etc. are important considerations in addition to the evidence. Although guidelines for the treatment of GIST have also been published by the National Comprehensive Cancer Network (NCCN) and the European Society for Medical Oncology (ESMO), there are some differences between the treatments proposed in those guidelines and the treatments in the present guidelines because of the differences in health insurance systems among countries.

Transcatheter Arterial Embolization for Bleeding Caused by Endoscopic Ultrasound-Guided Fine-Needle Aspiration: A Case Series.

Introduction Bleeding is the most frequent complication of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). In a few cases of massive bleeding caused by EUS-FNA, transcatheter arterial embolization (TAE) has been used to obtain hemostasis. We present a case series of patients who underwent TAE for bleeding due to EUS-FNA. Methods This case series included six patients (five men and one woman) who underwent TAE for bleeding caused by EUS-FNA between January 2018 and December 2022 at the four institutions involved in this study. The median age at TAE was 72.5 years (range, 67-83 years). The target sites for EUS-FNA were the pancreatic tail (n = 3), pancreatic head (n = 2), and hepatic hilar lymph nodes (n = 1). The angiographic findings, embolization procedures, technical and clinical success rates, and TAE complications were retrospectively assessed. Results Angiography revealed contrast-media extravasation or pseudoaneurysms in five patients. In all patients, TAE using a microcatheter was performed via the transfemoral approach. N-butyl cyanoacrylate, coils, and gelatin sponges were used for embolization. The technical and clinical success rates of TAE were 100%. One complication, a duodenal ulcer, developed in one patient and was managed conservatively. Conclusion TAE is an effective and safe treatment for EUS-FNA-induced bleeding.

Utility of Diffusion-weighted MR Imaging for Evaluating the Depth of Invasion in Oral Tongue Squamous Cell Carcinoma.

PURPOSE: The 8th edition of the American Joint Committee on Cancer staging system included the depth of invasion (DOI) for the T classification of oral cancer. However, no standardized method has been established to clinically measure the DOI. This study aimed to investigate the accuracy of MRI-based DOI for oral tongue squamous cell carcinoma (OTSCC) in each MRI sequence. METHODS: We enrolled 49 patients with histologically proven OTSCC, treated surgically between April 2017 and February 2021. We divided the DOI into three groups using 5 and 10 mm, the thresholds for determining the T stage, and retrospectively evaluated the agreement between MRI-based DOI and pathological DOI (pDOI) for each MRI sequence, axial T1-weighted imaging (T1WI), T2-weighted imaging with fat suppression (FS-T2WI), contrast-enhanced T1WI with fat suppression (CE-T1WI), diffusion-weighted imaging (DWI), and apparent diffusion coefficient (ADC) maps. We also divided the DOI into two groups using 3 mm, the threshold for considering elective neck dissection, and evaluated the overestimation rate of MRI-based DOI in lesions with pDOI ≤ 3 mm. RESULTS: With 5-mm and 10-mm divisions, the accuracy of the DOI assessment was highest on DWI (0.82, weighted kappa = 0.85). With a 3-mm division, the accuracy was also highest on DWI (0.87, kappa = 0.73). The overestimation rate of the MRI-based DOI in lesions with pDOI ≤ 3 mm was lowest on DWI (27.8%). CONCLUSION: DOI on DWI exhibits a comparatively higher rate of concordance with pDOI. DWI may be more useful than other MRI sequences in evaluating the DOI of OTSCC.

Thin-slice reverse encoding distortion correction DWI facilitates visualization of non-functioning pituitary neuroendocrine tumor (PitNET)/pituitary adenoma and surrounding normal structures.

BACKGROUND: To evaluate the clinical usefulness of thin-slice echo-planar imaging (EPI)-based diffusion-weighted imaging (DWI) with an on-console distortion correction technique, termed reverse encoding distortion correction DWI (RDC-DWI), in patients with non-functioning pituitary neuroendocrine tumor (PitNET)/pituitary adenoma. METHODS: Patients with non-functioning PitNET/pituitary adenoma who underwent 3-T RDC-DWI between December 2021 and September 2022 were retrospectively enrolled. Image quality was compared among RDC-DWI, DWI with correction for distortion induced by B0 inhomogeneity alone (B0-corrected-DWI), and original EPI-based DWI with anterior-posterior phase-encoding direction (AP-DWI). Susceptibility artifact, anatomical visualization of cranial nerves, overall tumor visualization, and visualization of cavernous sinus invasion were assessed qualitatively. Quantitative assessment of geometric distortion was performed by evaluation of anterior and posterior displacement between each DWI and the corresponding three-dimensional T2-weighted imaging. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient values were measured. RESULTS: Sixty-four patients (age 70.8 ± 9.9 years [mean ± standard deviation]; 33 females) with non-functioning PitNET/pituitary adenoma were evaluated. In terms of susceptibility artifacts in the frontal and temporal lobes, visualization of left trigeminal nerve, overall tumor visualization, and anterior displacement, RDC-DWI performed the best and B0-corrected-DWI performed better than AP-DWI. The right oculomotor and right trigeminal nerves were better visualized by RDC-DWI than by B0-corrected-DWI and AP-DWI. Visualization of cavernous sinus invasion and posterior displacement were better by RDC-DWI and B0-corrected-DWI than by AP-DWI. SNR and CNR were the highest for RDC-DWI. CONCLUSIONS: RDC-DWI achieved excellent image quality regarding susceptibility artifact, geometric distortion, and tumor visualization in patients with non-functioning PitNET/pituitary adenoma. RELEVANCE STATEMENT: RDC-DWI facilitates excellent visualization of the pituitary region and surrounding normal structures, and its on-console distortion correction technique is convenient. RDC-DWI can clearly depict cavernous sinus invasion of PitNET/pituitary adenoma even without contrast medium. KEY POINTS: • RDC-DWI is an EPI-based DWI technique with a novel on-console distortion correction technique. • RDC-DWI corrects distortion due to B0 field inhomogeneity and eddy current. • We evaluated the usefulness of thin-slice RDC-DWI in non-functioning PitNET/pituitary adenoma. • RDC-DWI exhibited excellent visualization in the pituitary region and surrounding structures. • In addition, the on-console distortion correction of RDC-DWI is clinically convenient.

Association Between Pancreatic Cysts and Diabetes Mellitus in Von Hippel-Lindau Disease.

INTRODUCTION: Pancreatic cysts are frequently observed in patients with von Hippel-Lindau disease (VHL), and they are considered clinically not important. This study aimed to evaluate the association between pancreatic cysts and diabetes mellitus (DM) in patients with VHL. METHODS: Among patients who were on a patient list at the VHL Center at Kyoto University Hospital as of December 2022, those who had undergone an upper abdominal magnetic resonance imaging study after 2010 were retrospectively evaluated. The presence or absence of DM and high glycated hemoglobin (HbA1c) levels (>6.0%) were assessed. Patients were divided into two groups: those with DM or high HbA1c levels, and those without DM or high HbA1c levels. The area of the whole pancreas, including the pancreatic cysts and tumors, the area of the pancreatic cysts, and the percentage of pancreatic cysts, calculated by dividing the area of pancreatic cysts by the area of the whole pancreas, were measured on T2-weighted magnetic resonance images and compared between the two groups. RESULTS: Thirty-six patients with VHL, comprising 22 men and 14 women, with a mean age of 36.4 years (range, 11-79 years), were identified. Seven patients had DM, and two additional patients had high HbA1c levels. The area of the pancreatic cysts (p = 0.0013) was significantly larger and the percentage of the pancreatic cysts (p = 0.0016) was significantly higher in patients with DM or high HbA1c levels (n = 9) than in patients without DM or high HbA1c levels (n = 27); however, the difference in the area of the whole pancreas was not significant (p = 0.068). CONCLUSION: Our findings suggest that patients with VHL who have a large area covered by pancreatic cysts are more likely to have DM than those without.

Transarterial Embolization of Type 2 Endoleak Post Thoracic Endovascular Aortic Repair (TEVAR) Using a Triaxial System With a 1.3-F Microcatheter: A Case Report.

Although transarterial embolization is recognized as a treatment for type 2 endoleaks, it can occasionally be challenging. We report the case of an 86-year-old man who presented with an enlarging thoracoabdominal aortic aneurysm following thoracic endovascular aortic repair. Using a triaxial system with a 1.3-F microcatheter, transarterial embolization of a type 2 endoleak was successfully performed through a long and tortuous arterial route comprising the thoracodorsal and ninth intercostal arteries. The postoperative clinical course was uneventful, and computed tomography obtained six days later showed no endoleak in the thoracoabdominal aortic aneurysm. This case suggests the usefulness of a triaxial system with a 1.3-F microcatheter for transarterial embolization of type 2 endoleaks.

18F-FDG PET/CT in left atrial undifferentiated pleomorphic sarcoma with osteosarcomatous differentiation.

Primary cardiac sarcomas are rare and sometimes difficult to discern from benign tumors and intracardiac thrombi. We describe the ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT findings in a case of left atrial undifferentiated pleomorphic sarcoma with osteosarcomatous differentiation, presenting with severe mitral regurgitation and pulmonary hypertension. The tumor presented as a broad-base mass protruding into the cardiac lumen, accompanied by punctate calcification-like high attenuation on CT. 18F-FDG PET/CT revealed high 18F-FDG uptake in the mass. Severe mitral regurgitation, a rare manifestation, was caused by tumor extension to the mitral valve leaflets and subvalvular tissue, which was best visualized on transesophageal echocardiography. This case illustrates the importance of multimodal diagnostic approaches including 18F-FDG PET/CT, which can facilitate accurate diagnosis and timely initiation of curative treatment, ultimately saving the patient's life. Learning objective: Firstly, cardiac sarcomas, particularly those with calcification/ossification, are rare and may mimic benign tumors and chronic intracardiac thrombi. Multimodal imaging approach, including 18F-FDG PET/CT, may be helpful in the accurate diagnosis of malignancies. Second, left atrial undifferentiated pleomorphic sarcoma has the potential to extensively spread along the endocardium and can extend to involve the valve leaflets, resulting in mitral regurgitation and pulmonary hypertension.

Hyalinizing Clear Cell Carcinoma in the Sphenoid Sinus.

ABSTRACT: A 39-year-old man presented with a 1-month history of headaches. Imaging revealed a mass with extensive destruction. T2-weighted imaging displayed mixture of low and sponge-like high intensities and also dark area, with FDG PET/CT showing uneven but intense accumulation. Biopsy confirmed EWSR1 rearrangement, and hyalinizing clear cell carcinoma (HCCC) was diagnosed. HCCC, recently renamed from clear cell carcinoma in the fifth edition of the World Health Organization Classification of Head and Neck Tumors, is a rare tumor. This case describes the features of T2-weighted imaging and FDG PET patterns in HCCC, possibly contributing to their consideration in the differential diagnosis.

Convolutional neural network-based program to predict lymph node metastasis of non-small cell lung cancer using 18F-FDG PET.

PURPOSE: To develop a convolutional neural network (CNN)-based program to analyze maximum intensity projection (MIP) images of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) scans, aimed at predicting lymph node metastasis of non-small cell lung cancer (NSCLC), and to evaluate its effectiveness in providing diagnostic assistance to radiologists. METHODS: We obtained PET images of NSCLC from public datasets, including those of 435 patients with available N-stage information, which were divided into a training set (n = 304) and a test set (n = 131). We generated 36 maximum intensity projection (MIP) images for each patient. A residual network (ResNet-50)-based CNN was trained using the MIP images of the training set to predict lymph node metastasis. Lymph node metastasis in the test set was predicted by the trained CNN as well as by seven radiologists twice: first without and second with CNN assistance. Diagnostic performance metrics, including accuracy and prediction error (the difference between the truth and the predictions), were calculated, and reading times were recorded. RESULTS: In the test set, 67 (51%) patients exhibited lymph node metastases and the CNN yielded 0.748 predictive accuracy. With the assistance of the CNN, the prediction error was significantly reduced for six of the seven radiologists although the accuracy did not change significantly. The prediction time was significantly reduced for five of the seven radiologists with the median reduction ratio 38.0%. CONCLUSION: The CNN-based program could potentially assist radiologists in predicting lymph node metastasis by increasing diagnostic confidence and reducing reading time without affecting diagnostic accuracy, at least in the limited situations using MIP images.

Recent topics in fibroblast activation protein inhibitor-PET/CT: clinical and pharmacological aspects.

Recently, positron emission tomography (PET) with fibroblast activation protein inhibitor (FAPI) has gained significant attention as an advanced tumor diagnostic imaging tool. FAPI PET has a promising potential owing to its ability to accurately depict most malignant tumors. It has an accuracy that is comparable to or surpassing the diagnostic accuracy of PET using 18F-fluorodeoxyglucose (FDG). Moreover, FAPI PET can identify malignant lesions that may be inconclusive on FDG PET. Beyond its application in neoplastic disorders, there have been encouraging reports suggesting the utility of FAPI PET in non-neoplastic conditions such as respiratory or cardiac diseases. This article aimed to provide a comprehensive overview of the recently published articles investigating FAPI and discuss its clinical utility with an emphasis on its application in tumor diagnostics. Numerous radiopharmaceutical FAPIs, including 18F- and 68Ga-labeled compounds, have been developed, and they offer various advantages and applications. With the progress in the FAPI PET synthesis to enhance accumulation and retention in pathological lesions, future studies are expected to provide valuable data on its therapeutic efficacy.

Vessel wall MRI in moyamoya disease: arterial wall enhancement varies depending on age, arteries, and disease progression.

OBJECTIVE: To investigate the relationship of followings for patients with moyamoya disease (MMD): arterial wall enhancement on vessel wall MRI (VW-MRI), cross-sectional area (CSA), time-of-flight MR angiography (MRA), age, locations from intracranial internal carotid artery (ICA) to proximal middle cerebral artery (MCA), disease progression, and transient ischemic attack (TIA). METHODS: Patients who underwent VW-MRI between October 2018 and December 2020 were enrolled in this retrospective study. We measured arterial wall enhancement (enhancement ratio, ER) and CSA at five sections of ICA and MCA. Also, we scored MRA findings. Multiple linear regression (MLR) analysis was performed to explore the associations between ER, age, MRA score, CSA, history of TIA, and surgical revascularization. RESULTS: We investigated 102 sides of 51 patients with MMD (35 women, 16 men, mean age 31 years ± 18 [standard deviation]). ER for MRA score 2 (signal discontinuity) was higher than ER for other scores in sections D (end of ICA) and E (proximal MCA) on MLR analysis. ER in section E was significantly higher in patients for MRA score 2 with TIA history than without. ER significantly increased as CSA increased in section E, which suggests ER becomes less in decreased CSA due to negative remodeling. CONCLUSION: Arterial wall enhancement in MMD varies by age, location, and disease progression. Arterial wall enhancement may be stronger in the progressive stage of MMD. Arterial wall enhancement increases with history of TIA at proximal MCA, which may indicate the progression of the disease. CLINICAL RELEVANCE STATEMENT: Arterial wall enhancement in moyamoya disease varies by age, location of arteries, and disease progression, and arterial wall enhancement may be used as an imaging biomarker of moyamoya disease. KEY POINTS: It has not been clarified what arterial wall enhancement in moyamoya disease represents. Arterial wall enhancement in moyamoya disease varies by age, location of arteries, and disease progression. Arterial wall enhancement in moyamoya disease increases as the disease progresses.

Ultrafast Dynamic Contrast-Enhanced MRI of the Breast: From Theory to Practice.

The development of ultrafast dynamic contrast-enhanced (UF-DCE) MRI has occurred in tandem with fast MRI scan techniques, particularly view-sharing and compressed sensing. Understanding the strengths of each technique and optimizing the relevant parameters are essential to their implementation. UF-DCE MRI has now shifted from research protocols to becoming a part of clinical scan protocols for breast cancer. UF-DCE MRI is expected to compensate for the low specificity of abbreviated MRI by adding kinetic information from the upslope of the time-intensity curve. Because kinetic information from UF-DCE MRI is obtained from the shape and timing of the initial upslope, various new kinetic parameters have been proposed. These parameters may be associated with receptor status or prognostic markers for breast cancer. In addition to the diagnosis of malignant lesions, more emphasis has been placed on predicting and evaluating treatment response because hyper-vascularity is linked to the aggressiveness of breast cancers. In clinical practice, it is important to note that breast lesion images obtained from UF-DCE MRI are slightly different from those obtained by conventional DCE MRI in terms of morphology. A major benefit of using UF-DCE MRI is avoidance of the marked or moderate background parenchymal enhancement (BPE) that can obscure the target enhancing lesions. BPE is less prominent in the earlier phases of UF-DCE MRI, which offers better lesion-to-noise contrast. The excellent contrast of early-enhancing vessels provides a key to understanding the detailed pathological structure of tumor-associated vessels. UF-DCE MRI is normally accompanied by a large volume of image data for which automated/artificial intelligence-based processing is expected to be useful. In this review, both the theoretical and practical aspects of UF-DCE MRI are summarized. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 2.

Dual Lumen Microcatheter in Percutaneous Biliary Drainage for Postoperative Bile Leakage: A Case Report.

Percutaneous biliary intervention is widely accepted as an effective and safe treatment for various types of bile duct diseases. We present the case of a 44-year-old woman who developed bile leakage after a living-donor liver transplantation for locally advanced cholangiocarcinoma. A percutaneous drainage tube was placed in the segment 8 bile duct via the blind end of the jejunum. However, the bile leakage was unchanged. Bile leakage from the right posterior hepatic duct was suspected. Using a dual lumen microcatheter, a percutaneous drainage tube was placed in the segment 7 bile duct via the blind end of the jejunum, which reduced the bile leakage. These results suggest that a dual lumen microcatheter is a valuable tool for navigating the biliary tree during difficult percutaneous biliary interventions.