Analysis of domain shift in whole prostate gland, zonal and lesions segmentation and detection, using multicentric retrospective data.

Despite being one of the most prevalent forms of cancer, prostate cancer (PCa) shows a significantly high survival rate, provided there is timely detection and treatment. Computational methods can help make this detection process considerably faster and more robust. However, some modern machine-learning approaches require accurate segmentation of the prostate gland and the index lesion. Since performing manual segmentations is a very time-consuming task, and highly prone to inter-observer variability, there is a need to develop robust semi-automatic segmentation models. In this work, we leverage the large and highly diverse ProstateNet dataset, which includes 638 whole gland and 461 lesion segmentation masks, from 3 different scanner manufacturers provided by 14 institutions, in addition to other 3 independent public datasets, to train accurate and robust segmentation models for the whole prostate gland, zones and lesions. We show that models trained on large amounts of diverse data are better at generalizing to data from other institutions and obtained with other manufacturers, outperforming models trained on single-institution single-manufacturer datasets in all segmentation tasks. Furthermore, we show that lesion segmentation models trained on ProstateNet can be reliably used as lesion detection models.

Imaging of pancreatic ductal adenocarcinoma - An update for all stages of patient management.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a common and lethal cancer. From diagnosis to disease staging, response to neoadjuvant therapy assessment and patient surveillance after resection, imaging plays a central role, guiding the multidisciplinary team in decision-planning. Review aims and findings: This review discusses the most up-to-date imaging recommendations, typical and atypical findings, and issues related to each step of patient management. Example cases for each relevant condition are presented, and a structured report for disease staging is suggested. Conclusion: Despite current issues in PDAC imaging at different stages of patient management, the radiologist is essential in the multidisciplinary team, as the conveyor of relevant imaging findings crucial for patient care.

Diffusion-weighted imaging for determining response to neoadjuvant therapy in pancreatic cancer: a systematic review and meta-analysis.

OBJECTIVES: To determine the role of diffusion-weighted imaging (DWI) for predicting response to neoadjuvant therapy (NAT) in pancreatic cancer. MATERIALS AND METHODS: MEDLINE, EMBASE, and Cochrane Library databases were searched for studies evaluating the performance of apparent diffusion coefficient (ADC) to assess response to NAT. Data extracted included ADC pre- and post-NAT, for predicting response as defined by imaging, histopathology, or clinical reference standards. ADC values were compared with standardized mean differences. Risk of bias was assessed using the Quality Assessment of Diagnostic Studies (QUADAS-2). RESULTS: Of 337 studies, 7 were included in the analysis (161 patients). ADC values reported for the pre- and post-NAT assessments overlapped between responders and non-responders. One study reported inability of ADC increase after NAT for distinguishing responders and non-responders. A correlation with histopathological response was reported for pre- and post-NAT ADC in 4 studies. DWI's diagnostic performance was reported to be high in three studies, with a 91.6-100% sensitivity and 62.5-94.7% specificity. Finally, heterogeneity and high risk of bias were identified across studies, affecting the domains of patient selection, index test, reference standard, and flow and timing. CONCLUSION: DWI might be useful for determining response to NAT in pancreatic cancer. However, there are still too few studies on this matter, which are also heterogeneous and at high risk for bias. Further studies with standardized procedures for data acquisition and accurate reference standards are needed. CLINICAL RELEVANCE STATEMENT: Diffusion-weighted MRI might be useful for assessing response to neoadjuvant therapy in pancreatic cancer. However, further studies with robust data are needed to provide specific recommendations for clinical practice. KEY POINTS: •The role of DWI with ADC measurements for assessing response to neoadjuvant therapy in pancreatic cancer is still unclear. •Pre- and post-neoadjuvant therapy ADC values overlap between responders and non-responders. •DWI has a reported high diagnostic performance for determining response when using histopathological or clinical reference standards; however, studies are still few and at high risk for bias.

Multiple Myeloma-Derived Extracellular Vesicles Modulate the Bone Marrow Immune Microenvironment.

Multiple myeloma (MM), the third most frequent hematological cancer worldwide, is characterized by the proliferation of neoplastic plasma cells in the bone marrow (BM). One of the hallmarks of MM is a permissive BM microenvironment. Increasing evidence suggests that cell-to-cell communication between myeloma and immune cells via tumor cell-derived extracellular vesicles (EV) plays a key role in the pathogenesis of MM. Hence, we aimed to explore BM immune alterations induced by MM-derived EV. For this, we inoculated immunocompetent BALB/cByJ mice with a myeloma cell line, MOPC315.BM, inducing a MM phenotype. Upon tumor establishment, characterization of the BM microenvironment revealed the expression of both activation and suppressive markers by lymphocytes, such as granzyme B and PD-1, respectively. In addition, conditioning of the animals with MOPC315.BM-derived EV, before transplantation of the MOPC315.BM tumor cells, did not anticipate the disease phenotype. However, it induced features of suppression in the BM milieu, such as an increase in PD-1 expression by CD4+ T cells. Overall, our findings reveal the involvement of MOPC315.BM-derived EV protein content as promoters of immune niche remodeling, strengthening the importance of assessing the mechanisms by which MM may impact the immune microenvironment.

Diagnostic value of morphological enhancement patterns in the hepatobiliary phase of gadoxetic acid-enhanced MRI to distinguish focal nodular hyperplasia from hepatocellular adenoma.

OBJECTIVES: To describe the different morphological enhancement patterns of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI (Gd-EOB-DTPA MRI) and to determine their added value in their differential diagnosis. METHODS: A retrospective analysis of imaging findings in 185 benign hepatocellular lesions (154 FNH; 31 HCA) in 108 patients who underwent Gd-EOB-DTPA MRI was performed by two independent reviewers. Six patterns on HBP were recorded: 1) homogeneous enhancement; 2) peripheral ring-like enhancement with hypointense central core; 3) peripheral ring-like enhancement with hyperintense central core; 4) central core enhancement with hypointense periphery; 5) heterogeneous enhancement; and 6) the absence of enhancement. RESULTS: Peripheral ring-like enhancement with hypointense central core and peripheral ring-like enhancement with hyperintense central core showed the highest specificity for the diagnosis of FNH (100% and 96.8%, respectively). The absence of enhancement and central core enhancement with hypointense periphery were only present in 0.6% and 1.9% of FHN, respectively. All other patterns were observed with similar frequencies in FNH (22.1% to 26.6%). Six HCA showed contrast uptake on the HBP: homogeneous (6.5%), peripheral ring-like enhancement with hyperintense central core (3.2%) and heterogeneous (9.7%). CONCLUSION: Both FNH and HCA may demonstrate enhancement in the HBP of Gd-EOB-DTPA MRI, limiting its specificity. A significant improvement in specificity can be achieved by the evaluation of morphological enhancement patterns: Peripheral ring-like enhancement with hypointense or hyperintense central core was highly specific for FNH diagnosis. On the other hand, the absence of HBP enhancement makes the diagnosis of FNH unlikely.

Effective bowel motion reduction in mouse abdominal MRI using hyoscine butylbromide.

PURPOSE: Bowel motion is a significant source of artifacts in mouse abdominal MRI. Fasting and administration of hyoscine butylbromide (BUSC) have been proposed for bowel motion reduction but with inconsistent results and limited efficacy assessments. Here, we evaluate these regimes for mouse abdominal MRI at high field. METHODS: Thirty-two adult C57BL/6J mice were imaged on a 9.4T scanner with a FLASH sequence, acquired over 90 min with ~19 s temporal resolution. During MRI acquisition, 8 mice were injected with a low-dose and 8 mice with a high-dose bolus of BUSC (0.5 and 5 mg/kg, respectively). Eight mice were food deprived for 4.5-6.5 hours before MRI and another group of eight mice was injected with saline during MRI acquisition. Two expert readers reviewed the images and classified bowel motion, and quantitative voxel-wise analyses were performed for identification of moving regions. After defining the most effective protocol, high-resolution T2 -weighted and diffusion-weighted images were acquired from 4 mice. RESULTS: High-dose BUSC was the most effective protocol for bowel motion reduction, for up to 45 min. Fasting and saline protocols were not effective in suppressing bowel motion. High-resolution abdominal MRI clearly demonstrated improved image quality and ADC quantification with the high-dose BUSC protocol. CONCLUSION: Our data show that BUSC administration is advantageous for abdominal MRI in the mouse. Specifically, it endows significant bowel motion reduction, with relatively short onset timings after injection (~8.5 min) and relatively long duration of the effect (~45 min). These features improve the quality of high-resolution images of the mouse abdomen.

All about portal vein: a pictorial display to anatomy, variants and physiopathology.

The portal vein (PV) is the main vessel of the portal venous system (PVS), which drains the blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver. There are several variants affecting the PV, and quite a number of congenital and acquired pathologies.In this pictorial review, we assess the embryological development and normal anatomy of the PVS, displaying selected cases consisting of normal variants, congenital anomalies, and a large and heterogeneous group of acquired conditions that may affect the PV.

Ultrasound-guided Liver Biopsies in Children: A Single-center Experience and Risk Factors for Minor Bleeding.

OBJECTIVES: The aim of the study was to analyze the institution's experience in ultrasound-guided liver biopsies performed on children and identify risk factors for complications, following a previous study performed in our institution. METHODS: Retrospective analysis of a consecutive series of ultrasound-guided pediatric liver biopsies, between 2011 and 2016. Demographic and anthropometric data, biopsy indications, international normalized ratio (INR) and platelet count, biopsy technique, complications, and pathologic outcomes were recorded. RESULTS: A total of 228 procedures were performed on 203 children with a median age of 9.25 years (range: 0.08-18.42): 107 girls (47%) and 121 boys (53%). One hundred twenty-seven biopsies were performed on transplanted livers (55.7%) and 101 on native livers (44.3%). There were 27 cases with immediate complications (11.84%), all due to minor bleeding. There were no major complications. Increasing needle passes were shown to be a reliable predictor for bleeding (P = 0.0023), whereas transplanted livers predicted protection against bleeding (P = 0.0007). Age younger than 3 years, bodyweight <16 kg, platelet count <70 g/L and INR >1.25 revealed association with increased bleeding incidence, but no predictive value. CONCLUSION: Ultrasound-guided liver biopsies in pediatric age are a safe procedure with a high diagnostic yield. Increasing the number of needle passes predicts a higher incidence of minor bleeding. Other factors to account for minor bleeding risk may include age younger than 3 years, bodyweight <16 kg, platelet count <70 G/L, and INR >1.25. Transplanted livers present a lower bleeding risk.

Longitudinal stress fracture of the femur: A rare presentation.

We present the case of an 80 year old woman with hip pain, caused by a longitudinal femoral insufficiency stress fracture, depicted with radiographs, CT and MR. This type of fracture is very rare, with only a few cases reported. We conducted a literature review and compared the findings with the present case.