68Ga-DOTATATE PET/MRI for Neuroendocrine Tumors: A Pictorial Review.

Neuroendocrine tumors (NETs) constitute a variety of neoplastic entities and exhibit variable degrees of neuroendocrine differentiation and phenotypes, as well as genetic profiles. Ga-DOTATATE PET is a novel imaging technique for NET. Although PET/CT is commonly utilized for oncologic imaging, PET/MRI is particularly suited for NETs, as MRI provides greater soft tissue contrast than CT, allowing for improved detection and characterization of NETs, particularly when liver metastasis is suspected or needs to be ruled out. The current pictorial review aims to illustrate the complementary advantages, as well as pitfalls of Ga-DOTATATE PET/MRI in the evaluation of NETs.

Contribution of neural crest and GLAST+ Wnt1+ bone marrow pericytes with liver fibrogenesis and/or regeneration.

BACKGROUND AND AIMS: Liver fibrosis results from cycles of liver damage and scar formation. We herein aimed at analysing neural crest cells and/or bone marrow stromal cells contribution to the liver. METHODS: Two liver fibrosis and one hepatectomy model were applied on double-transgenic loxP-Cre mouse lines. RESULTS: Increased numbers of glia with more complex processes were found in fibrotic livers. During embryonic development, only few cells were traced in the liver and bone marrow, in a minor fraction of mice of different neural crest reporter strains analysed: therefore, a neural crest origin of such cells is doubtful. In the fibrotic liver, a significantly higher incidence of endothelial cells and hepatocyte-like cells expressing the reporter gene Tomato were found in Wnt1-Cre-Tom and GLAST-CreERT2-Tom mice. Consistently, during early fibrogenesis stromal Wnt1-traced cells, with progenitor (CFU-F) properties, get likely mobilized to peripheral blood. Circulating adult Wnt1-traced cells are stromal cells and lack from the expression of other bone marrow and endothelial progenitor cells markers. Furthermore, in a 70% hepatectomy model GLAST+ Wnt1-traced pericytes were found to be mobilized from the bone marrow and the incidence of GLAST-traced hepatocyte-like cells was increased. Finally, GLAST-traced hepatocyte like-cells were found to maintain the expression of stromal markers. CONCLUSIONS: Our data suggest a gliosis process during liver fibrogenesis. While neural crest cells probably do not contribute with other liver cell types than glia, GLAST+ Wnt1-traced bone marrow pericytes are likely a source of endothelial and hepatocyte-like cells after liver injury and do not contribute to scarring.

Comparison of 2D Shear Wave Elastography, Transient Elastography, and MR Elastography for the Diagnosis of Fibrosis in Patients With Nonalcoholic Fatty Liver Disease.

OBJECTIVE. The aim of the present study was to compare the diagnostic accuracy of liver stiffness measurements (LSMs) obtained using MR elastography (MRE), transient elastography (TE), and 2D shear wave elastography (SWE) in patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD). SUBJECTS AND METHODS. We prospectively enrolled 62 adult subjects (mean age [± SD], 50 ± 13 years; 58% women; body mass index [weight in kilograms divided by the square of height in meters], 35 ± 7). Two-dimensional SWE, MRE, and TE were performed at a mean of 105 ± 86 days after liver biopsy. The area under the ROC curve (AUROC) values and 95% CIs for the corresponding LSMs (expressed in kilopascals) were calculated, with significant fibrosis (Metavir liver fibrosis score, F2-F4) and advanced fibrosis (F3-F4) used as outcome measures. Pairwise comparisons of AUROC values were conducted using the DeLong test. Statistical significance was set at p < 0.05. RESULTS. For the 62 subjects, valid LSMs were obtained for 57 subjects with the use of 2D SWE, for 59 subjects with TE, for 59 subjects with MRE, and for 54 subjects with all three modalities combined. The AUROC values (95% CIs) of 2D SWE, TE, and MRE for the diagnosis of significant fibrosis were 0.80 (0.67-0.92), 0.77 (0.64-0.89), and 0.85 (0.74-0.95), respectively. The AUROC values (95% CIs) of 2D SWE, TE, and MRE for the diagnosis of advanced fibrosis were 0.89 (0.80-0.98), 0.86 (0.77-0.95), and 0.95 (0.89-1.00), respectively. Pairwise comparisons revealed similar diagnostic accuracy for significant fibrosis (2D SWE vs MRE, p = 0.431; 2D SWE vs TE, p = 0.317; and MRE vs TE, p = 0.052) and advanced fibrosis (2D SWE vs MRE, p = 0.348; 2D SWE vs TE, p = 0.293; and MRE vs TE, p = 0.059). CONCLUSION. For patients with biopsy-proven NAFLD, 2D SWE, MRE and TE exhibited comparable and very good to excellent diagnostic accuracy for advanced fibrosis and comparable but lower accuracy for significant fibrosis.

Increasing Utilization of Multiparametric Magnetic Resonance Imaging in Prostate Cancer Active Surveillance.

OBJECTIVE: To characterize the use of multiparametric magnetic resonance imaging (mpMRI) in male Medicare beneficiaries electing active surveillance for prostate cancer. mpMRI has emerged as a tool that may improve risk-stratification and decrease repeated biopsies in men electing active surveillance. However, the extent to which mpMRI has been implemented in active surveillance has not been established. METHODS: Using Surveillance, Epidemiology, and End Results registry data linked to Medicare claims data, we identified men with localized prostate cancer diagnosed between 2008 and 2013 and managed with active surveillance. We classified men into 2 treatment groups: active surveillance without mpMRI and active surveillance with mpMRI. We then fit a multivariable logistic regression models to examine changing mpMRI utilization over time, and factors associated with the receipt of mpMRI. RESULTS: We identified 9467 men on active surveillance. Of these, 8178 (86%) did not receive mpMRI and 1289 (14%) received mpMRI. The likelihood of receiving mpMRI over the entire study period increased by 3.7% (P = .004). On multivariable logistic regression, patients who were younger, white, had lower comorbidity burden, lived in the northeast and west, had higher incomes and lived in more urban areas had greater odds of receiving mpMRI (all P < .05). CONCLUSION: From 2008 to 2013, use of mpMRI in active surveillance increased gradually but significantly. Receipt of mpMRI among men on surveillance for prostate cancer varied significantly across demographic, geographic, and socioeconomic strata. Going forward, studies should investigate causes for this variation and define ideal strategies for equitable, cost-effective dissemination of mpMRI technology.

Clinical Profile and Natural Course in a Large Cohort of Patients With Hypertriglyceridemia and Pancreatitis.

GOALS: To report the clinical profile and natural course in a large series of patients with hypertriglyceridemia (HTG) and acute pancreatitis (AP). BACKGROUND: The natural history of HTG-related pancreatitis is poorly defined. STUDY: Medical records of 121 patients with serum triglycerides (TG) levels of ≥500 mg/dL suffering 225 attacks of AP between January 2001 to August 2013 treated at the University of Pittsburgh Medical Center were retrospectively studied. Structured data were collected on initial presentation and long-term outcomes (mean follow-up 64.7±42.8 mo). AP severity was classified using Revised Atlanta Classification. RESULTS: Most patients were young-middle aged (mean 44±12.7 y), male (70%), white (78%), and had sentinel AP (63%). Peak serum TG recorded was ≥1000 mg/dL in 48%. At least 1 secondary risk factor (diabetes, high-risk drinking, obesity, offending medications) was present in the majority (78%). Sentinel AP attack varied in severity between mild (41%), moderate (26%), and severe (33%). Recurrent AP attacks occurred in 32%, often in patients with poorly controlled diabetes, alcoholism, and TG levels. A cumulative increase in prevalence of pancreatic and/or peripancreatic necrosis was observed, with 45% patients having it at some time during observation. Local complications were higher in patients with serum TG ≥1000 mg/dL. Chronic pancreatitis was noted in 16.5% patients (new-onset in 9%). CONCLUSIONS: Patients with HTG-related pancreatitis have a high prevalence of secondary risk factors. Frequent recurrences in them are usually due to poor control of secondary factors or TG. Serum TG ≥1000 mg/dL increases the risk of local complications. A subset can have or develop chronic pancreatitis.

Isolated Peripancreatic Necrosis in Acute Pancreatitis Is Infrequent and Leads to Severe Clinical Course Only When Extensive: A Prospective Study From a US Tertiary Center.

GOALS: To explore the diagnostic challenges, management, and clinical outcomes of patients with isolated peripancreatic necrosis (PPN), with emphasis on the extent of involvement, and compare them to pancreatic necrosis (PN). BACKGROUND: PPN, a relatively new term, has been included as a separate entity in the Revised Atlanta Classification. STUDY: Clinical data of recruited acute pancreatitis patients were recorded prospectively. Contrast-enhanced computed tomographic scans were reviewed by expert radiologists blinded to clinical outcomes. RESULTS: In total, 271 of the 400 acute pancreatitis patients underwent contrast-enhanced computed tomography, of which 29 (11%) had PPN (14: limited; 15: extensive) and 124 (46%) PN (40: <30%, 16: 30% to 50%, 68: >50% of parenchyma). Patients with PPN were similar to PN in age (56 y), gender (55% male), and body mass index (29 kg/m(2)). Nutritional support was provided in 18 (62%) patients with PPN and 97 (78%) with PN (P=0.12). Drainage/debridement was required in 2 patients (7%) with PPN and 64 (53%) with parenchymal necrosis (P<0.001). Persistent organ failure rates did not differ significantly (34% vs. 51%, P=0.17), but hospital stay was shorter in patients with PPN (15 vs. 20 d, P=0.05). Limited PPN required no intervention and had similar persistent organ failure rates and hospitalization length with interstitial pancreatitis (both P≥0.12). Extensive PPN mainly developed in patients with persistent organ failure (60%) and rarely required drainage (2/15). CONCLUSIONS: PPN prevalence was lower than PN with a ratio of 1:4. PPN rarely required intervention. Utilizing the extent of involvement has the potential to classify PPN and PN with escalating clinical significance and guide management.