Effect of Time-of-Flight and Regularized Reconstructions on Quantitative Measurements and Qualitative Assessments in Newly Diagnosed Prostate Cancer With 18F-Fluorocholine Dual Time Point PET/MRI.

Recent technical advances in positron emission tomography/magnetic resonance imaging (PET/MRI) technology allow much improved time-of-flight (TOF) and regularized iterative PET reconstruction regularized iterative reconstruction (RIR) algorithms. We evaluated the effect of TOF and RIR on standardized uptake values (maximum and peak SUV [SUVmax and SUVpeak]) and their metabolic tumor volume dependencies and visual image quality for 18F-fluorocholine PET/MRI in patients with newly diagnosed prostate cancer. Fourteen patients were administered with 3 MBq/kg of 18F-fluorocholine and scanned dynamically for 30 minutes. Positron emission tomography images were divided to early and late time points (1-6 minutes summed and 7-30 minutes summed). The values of the different SUVs were documented for dominant PET-avid lesions, and metabolic tumor volume was estimated using a 50% isocontour and SUV threshold of 2.5. Image quality was assessed via visual acuity scoring (VAS). We found that incorporation of TOF or RIR increased lesion SUVs. The lesion to background ratio was not improved by TOF reconstruction, while RIR improved the lesion to background ratio significantly ( P < .05). The values of the different VAS were all significantly higher ( P < .05) for RIR images over TOF, RIR over non-TOF, and TOF over non-TOF. In conclusion, our data indicate that TOF or RIR should be incorporated into current protocols when available.

MR enterography under the age of 10 years: a single institutional experience.

BACKGROUND: MR enterography (MRE) plays a major role in the imaging of pediatric patients with inflammatory bowel disease (IBD) but can be challenging to perform in young children. OBJECTIVE: To review our institutional experience regarding the performance of MRE in children younger than 10 years of age, including the use of general anesthesia (GA). MATERIALS AND METHODS: Institutional review board approval was obtained. Radiology and anesthesia records were searched to identify MRE exams in children younger than 10 years old between June 2009 and May 2013. The following information was documented: demographics, indications for MRE, use of GA, imaging diagnoses, and documented GA-related side effects or adverse events. Imaging was reviewed to document study length, quality and progression of oral contrast material. RESULTS: One hundred six children (59 boys [56%]) younger than 10 years old underwent 119 MRE examinations (age range: 1 month to 9 years, 11 months). Common indications for MRE included known IBD (42%) and suspected IBD (38%). One hundred ten (92%) examinations were performed under GA. Mean exam length was 52 ± 13 min for GA patients with a range of 31--113 min. Median time under GA was 155 min. Oral contrast material reached the terminal ileum in 31%. Side effects/adverse events associated with GA were uncommon and minor, including transient nausea in 13 children (11%) and emesis in 9 (8%). CONCLUSION: Diagnostic-quality MRE can be performed successfully in young children. The majority of MRE exams were performed under GA, with only occasional minor side effects/adverse events.

Pediatric MR enterography: technique and approach to interpretation-how we do it.

Magnetic resonance (MR) enterography is an increasingly important pediatric imaging modality that is most often used to evaluate inflammatory bowel disease ( IBD inflammatory bowel disease ), while sparing children and adolescents from potential risks of ionizing radiation exposure. MR enterography allows for evaluation of the bowel lumen and wall, adjacent mesentery and soft tissues, as well as a variety of extraintestinal abdominopelvic IBD inflammatory bowel disease manifestations. While MR enterography can be used to initially confirm the diagnosis of IBD inflammatory bowel disease , particularly small bowel Crohn disease, it has also proven useful in assessing the degree inflammatory activity over time, serving as a radiologic biomarker for response to medical therapy, and identifying a variety of disease-related complications, including strictures, fistulae, and abscesses. The purpose of this review article is to provide radiologists with a systematic approach for MR enterography review and interpretation in children and adolescents with known or suspected of having IBD inflammatory bowel disease and to illustrate both common and infrequent but important imaging findings. Additionally, the authors will present their well-established and clinically successful pediatric MR enterography protocol, up-to-date clinical indications for MR enterography, and briefly mention the role of MR enterography in assessing non- IBD inflammatory bowel disease abnormalities affecting the bowel. Online supplemental material is available for this article .