Influence of oral contrast type and volume on patient experience and quality of luminal distension at MR Enterography in Crohn's disease:an observational study of patients recruited to the METRIC trial

OBJECTIVES: To compare the distention quality and patient experience of oral mannitol and polyethylene glycol (PEG) for MRE. METHODS: This study is a retrospective, observational study of a subset of patients enrolled in a multicentre, prospective trial evaluating the diagnostic accuracy of MRE for small bowel Crohn’s. Overall and segmental MRE small bowel distention, from 105 patients (64 F, mean age 37) was scored from 0 = poor to 4 = excellent by two experienced observers (68 [65%] mannitol and 37 [35%] PEG). Additionally, 130 patients (77 F, mean age 34) completed a questionnaire rating tolerability of various symptoms immediately and 2 days after MRE (85 [65%] receiving mannitol 45 [35%] receiving PEG). Distension was compared between agents and between those ingesting ≤ 1 L or > 1 L of mannitol using the test of proportions. Tolerability grades were collapsed into “very tolerable,” “moderately tolerable,” and “not tolerable.” RESULTS: Per patient distension quality was similar between agents (“excellent” or “good” in 54% [37/68] versus 46% [17/37]) with mannitol and PEG respectively. Jejunal distension was significantly better with mannitol compared to PEG (40% [27/68] versus 14% [5/37] rated as excellent or good respectively). There was no significant difference according to the volume of mannitol ingested. Symptom tolerability was comparable between agents, although fullness following MRE was graded as “very tolerable” in 27% (12/45) of patients ingesting PEG, verses 44% (37/84) ingesting mannitol, difference 17% (95% CI 0.6 to 34%). CONCLUSION: Mannitol-based solutions and PEG generally achieve comparable distension quality and side effect profiles, although jejunal distension is better quality with mannitol. Neither distension quality nor side-effect profile is altered by ingestion of more than 1 L of mannitol. KEY POINTS: • Mannitol-based and PEG-based oral preparation agents generally achieve comparable distension quality for MRE with the exception of the jejunum which is better distended with mannitol. • Mannitol-based and PEG-based oral preparation agents used for MRE have similar side effect profiles. • Neither distension quality nor side-effect profile is altered by ingestion of more than 1 L of mannitol. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00330-022-08614-9

Influence of diffusion weighted imaging and contrast enhanced T1 sequences on the diagnostic accuracy of magnetic resonance enterography for Crohn's disease

OBJECTIVES: To evaluate the additional diagnostic benefit of diffusion weighted imaging (DWI) and contrast enhanced (CE) images during MR enterography (MRE) of Crohn's disease. METHODS: Datasets from 73 patients (mean age 32; 40 male) (28 new-diagnosis, 45 relapsed) were read independently by two radiologists selected from a pool of 13. Radiologists interpreted datasets using three sequential sequence blocks: (1) T2 weighted and steady state free precession gradient echo (SSFP) images alone (T2^); (2) T2 weighted and SSFP images with DWI (T2 + DWI^) and; (3) T2 weighted images, SSFP, DWI and post-contrast enhanced (CE) T1 images (T2 + DWI + CE^), documenting presence, location, and activity of small bowel disease. For each sequence block, sensitivity and specificity (readers combined) was calculated against an outcome-based construct reference standard. RESULTS: 59/73 patients had small bowel disease. Per-patient sensitivity for disease detection was essentially identical (80 % [95 % CI 72, 86], 81 % [73,87], and 79 % [71,86] for T2^, T2 + DWI^and T2 + DWI + CE^respectively). Specificity was identical (82 % [64 to 92]). Per patient sensitivity for disease extent was 56 % (47,65), 56 % (47,65) and 52 % (43 to 61) respectively, and specificity was 82 % (64 to 92) for all blocks. Sensitivity for active disease was 97 % (90,99), 97 % (90,99) and 98 % (92,99), and specificity was also comparable between all sequence combination reads. Results were consistent across segments and newly diagnosed/relapse patients. CONCLUSION: There is no additional diagnostic benefit of adding either DWI or CE to T2 FSE and SSFP sequences for evaluating small bowel Crohn's disease, suggesting MRE protocols can be simplified safely

Influence of diffusion weighted imaging and contrast enhanced T1 sequences on the diagnostic accuracy of magnetic resonance enterography for Crohn's disease

OBJECTIVES: To evaluate the additional diagnostic benefit of diffusion weighted imaging (DWI) and contrast enhanced (CE) images during MR enterography (MRE) of Crohn's disease.METHODS: Datasets from 73 patients (mean age 32; 40 male) (28 new-diagnosis, 45 relapsed) were read independently by two radiologists selected from a pool of 13. Radiologists interpreted datasets using three sequential sequence blocks: (1) T2 weighted and steady state free precession gradient echo (SSFP) images alone (T2^); (2) T2 weighted and SSFP images with DWI (T2 + DWI^) and; (3) T2 weighted images, SSFP, DWI and post-contrast enhanced (CE) T1 images (T2 + DWI + CE^), documenting presence, location, and activity of small bowel disease. For each sequence block, sensitivity and specificity (readers combined) was calculated against an outcome-based construct reference standard.RESULTS: 59/73 patients had small bowel disease. Per-patient sensitivity for disease detection was essentially identical (80 % [95 % CI 72, 86], 81 % [73,87], and 79 % [71,86] for T2^, T2 + DWI^and T2 + DWI + CE^respectively). Specificity was identical (82 % [64 to 92]). Per patient sensitivity for disease extent was 56 % (47,65), 56 % (47,65) and 52 % (43 to 61) respectively, and specificity was 82 % (64 to 92) for all blocks. Sensitivity for active disease was 97 % (90,99), 97 % (90,99) and 98 % (92,99), and specificity was also comparable between all sequence combination reads. Results were consistent across segments and newly diagnosed/relapse patients.CONCLUSION: There is no additional diagnostic benefit of adding either DWI or CE to T2 FSE and SSFP sequences for evaluating small bowel Crohn's disease, suggesting MRE protocols can be simplified safely.</p

Modelling and Analysis of Electrical Discharge Alloying through Taguchi Technique

Electrical discharge alloying was performed on AISI D2 tool steel with addition of nickel powder. Taguchi method has been used to plan and analysis the experiment.The major parameters like Peak current, pulse on time, and pulse off are taken for this study for formation of alloyed layer. The influences of these process parameters have been identified by Signal to noise ratio (S/N) and analysis of variance (ANOVA) and their results are within the limits of predicted and experimental values. The experiments were conducted on a specially designed apparatus in laboratory itself. The layer thickness varies from 70 to 140 μm and the highest hardness value of 1788 HV0.3 with a lower specific wear rate.</jats:p

Micro-structure and self-lubricant properties of powder mixed electrical discharge metal matrix composite coating

In present exploration, Electric Discharge Alloying/Coating (EDA/C) is made over duplex stainless steel as alloying elements of nickel, graphite, copper (electrode) and pyrolysis carbon from oil together with substrate material results in metal matrix composite coating. Coating possess average hardness value of 1018 HV 0.5 four times higher and lowered specific wear rate of 1.18 × 10−5 mm3/N m with an improved average friction coefficient of 0.3 through Pin on Disc (POD) wear tester. Metallurgical properties of the coating are analysed through surface topography by 3D optical profilometer, coating microstructure over and across with elemental distribution are identified by electron microscope (SEM) attached with Energy-Dispersive X-Ray Spectroscopy (EDS). Phase transform from δ and γ of cementite with meta stable iron carbide appeared as austenitic structure are identified through Electron Probe Micro Analyser (EPMA) and by X-ray diffraction. This meta stable carbides together with alloying elements provides improved tensile and bonding strength at room temperature were else copper controls further phase transformation. Copper shows stick slip at lower loading up to 40 N then restores in temperature arises during frictional contacts makes carbon and carbide to plasticity state under room temperature provides self-lubricant properties. </jats:p

A comparison on microstructure and mechanical properties of electric discharge metal matrix nickel and silica composite coating on duplex stainless steel

Electric Discharge Alloying/Coating a thermal process of elemental deposition together with pyrolysis carbon enhance various properties. Nickel and silica both provide excellent property, but the solidification rate differs the material microstructural properties (amorphous) that improves its properties under diverse working conditions. In present study analysis of properties such as surface roughness, Microstructure, layer thickness, elemental composition, porosity, decarburizing depth is detailed through metallurgical characterizations and mechanical testing are compared to nickel and silica. Nickel holds a hardness value of 1272 HV and across 968 HV with minimal in carter, pokes, splatters having uniform boundaries that improves friction co-efficient, limiting wear resistant, phase transformation, oxidation, and graphite flakes confirm self-lubrication properties at room temperature under higher loading condition. Silica having 1284 HV on the surface and across it reaches to 980 HV due to dispersed elements and its phase transformation of silica to silica carbide directs secondary arching improves bonding by restrictive carbon deposition promotes passage to speak. This limits the porosity, coating layer thickness and increases metal matrix composition in decarburizing layer holds stability towards coating. Nickel affords surface properties limiting matrix composite, oxidation, and grain growth where else silica provides exceptional in metallurgical mixed composition improves the mechanical behaviour of coating. </jats:p