Quantitative MRCP Imaging: Accuracy, Repeatability, Reproducibility, and Cohort-Derived Normative Ranges.

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is an important tool for noninvasive imaging of biliary disease, however, its assessment is currently subjective, resulting in the need for objective biomarkers. PURPOSE: To investigate the accuracy, scan/rescan repeatability, and cross-scanner reproducibility of a novel quantitative MRCP tool on phantoms and in vivo. Additionally, to report normative ranges derived from the healthy cohort for duct measurements and tree-level summary metrics. STUDY TYPE: Prospective. PHANTOMS/SUBJECTS: Phantoms: two bespoke designs, one with varying tube-width, curvature, and orientation, and one exhibiting a complex structure based on a real biliary tree. Subjects Twenty healthy volunteers, 10 patients with biliary disease, and 10 with nonbiliary liver disease. SEQUENCE/FIELD STRENGTH: MRCP data were acquired using heavily T2 -weighted 3D multishot fast/turbo spin echo acquisitions at 1.5T and 3T. ASSESSMENT: Digital instances of the phantoms were synthesized with varying resolution and signal-to-noise ratio. Physical 3D-printed phantoms were scanned across six scanners (two field strengths for each of three manufacturers). Human subjects were imaged on four scanners (two fieldstrengths for each of two manufacturers). STATISTICAL TESTS: Bland-Altman analysis and repeatability coefficient (RC). RESULTS: Accuracy of the diameter measurement approximated the scanning resolution, with 95% limits of agreement (LoA) from -1.1 to 1.0 mm. Excellent phantom repeatability was observed, with LoA from -0.4 to 0.4 mm. Good reproducibility was observed across the six scanners for both phantoms, with a range of LoA from -1.1 to 0.5 mm. Inter- and intraobserver agreement was high. Quantitative MRCP detected strictures and dilatations in the phantom with 76.6% and 85.9% sensitivity and 100% specificity in both. Patients and healthy volunteers exhibited significant differences in metrics including common bile duct (CBD) maximum diameter (7.6 mm vs. 5.2 mm P = 0.002), and overall biliary tree volume 12.36 mL vs. 4.61 mL, P = 0.0026). DATA CONCLUSION: The results indicate that quantitative MRCP provides accurate, repeatable, and reproducible measurements capable of objectively assessing cholangiopathic change. Evidence Level: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:807-820.

Bioceramic nanocomposite thiol-acrylate polyHIPE scaffolds for enhanced osteoblastic cell culture in 3D.

Emulsion-templated (polyHIPE) scaffolds for bone tissue engineering were produced by photopolymerisation of a mixture of trimethylolpropane tris(3-mercaptopropionate) and dipentaerythritol penta-/hexa-acrylate in the presence of hydroxyapatite (HA) or strontium-modified hydroxyapatite (SrHA) nanoparticles. Porous and permeable polyHIPE materials were produced regardless of the type or incorporation level of the bioceramic, although higher loadings resulted in a larger average pore diameter. Inclusion of HA and SrHA into the scaffolds was confirmed by EDX-SEM, FTIR and XPS and quantified by thermogravimetry. Addition of HA to polyHIPE scaffolds significantly enhanced compressive strength (148-216 kPa) without affecting compressive modulus (2.34-2.58 MPa). The resulting materials were evaluated in vitro as scaffolds for the 3D culture of MG63 osteoblastic cells vs. a commercial 3D cell culture scaffold (Alvetex®). Cells were able to migrate throughout all scaffolds, achieving a high density by the end of the culture period (21 days). The presence of HA and in particular SrHA gave greatly enhanced cell proliferation, as determined by staining of histological sections and total protein assay (Bradford). Furthermore, Von Kossa and Alizarin Red staining demonstrated significant mineralisation from inclusion of bioceramics, even at the earliest time point (day 7). Production of alkaline phosphatase (ALP), an early osteogenic marker, was used to investigate the influence of HA and SrHA on cell function. ALP levels were significantly reduced on HA- and SrHA-modified scaffolds by day 7, which agrees with the observed early onset of mineralisation in the presence of the bioceramics. The presented data support our conclusions that HA and SrHA enhance osteoblastic cell proliferation on polyHIPE scaffolds and promote early mineralisation.

Preparation of hybrid thiol-acrylate emulsion-templated porous polymers by interfacial copolymerization of high internal phase emulsions.

Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 µm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying.