ObjectiveTo evaluate the utility of nerve diffusion tensor imaging (DTI), nerve cross‐sectional area, and muscle magnetic resonance imaging (MRI) multiecho Dixon for assessing proximal nerve injury in chronic inflammatory demyelinating polyneuropathy (CIDP).MethodsIn this prospective observational cohort study, 11 patients with CIDP and 11 healthy controls underwent a multiparametric MRI protocol with DTI of the sciatic nerve and assessment of muscle proton‐density fat fraction of the biceps femoris and the quadriceps femoris muscles by multiecho Dixon MRI. Patients were longitudinally evaluated by MRI, clinical examination, and nerve conduction studies at baseline and after 6 months.ResultsIn sciatic nerves of CIDP patients, mean cross‐sectional area was significantly higher and fractional anisotropy value was significantly lower, compared to controls. In contrast, muscle proton‐density fat fraction was significantly higher in thigh muscles of patients with CIDP, compared to controls. MRI parameters showed high reproducibility at baseline and 6 months.InterpretationAdvanced MRI parameters demonstrate subclinical proximal nerve damage and intramuscular fat accumulation in CIDP. Data suggest DTI and multiecho Dixon MRI might be useful in estimating axonal damage and neurogenic muscle changes in CIDP.

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Purpose: Retrospective evaluation and comparison of image quality generated by low-dose computed tomography (LDCT) from obese patients with urolithiasis using alternative reconstruction algorithms. Materials and methods: Twenty-five obese patients (body mass index [BMI]>25 kg/m 2 ) underwent LDCT scans for suspected urolithiasis. The scans were recompiled using filtered-back projection (FBP), statistical iterative reconstruction (iDose) and iterative model-based reconstruction (IMR). Dose-length product (DLP) and patient details were obtained from the CT dose report and clinical charts, respectively. Objective image noise was assessed by measuring the SD of Hounsfield units (HUs) in defined locations. Additionally, subjective image evaluation was independently performed by two radiologists using a 3-point Likert scale. The inter-reviewer agreement of image quality was calculated. Results: Ureteral concretions were observed in all CT scans, two of which revealed bilateral stones. The assessed patients’ mean BMI was 29.29±3.74 kg/m 2 , and the DLP of the CT scans was 100.04±10.00 mGy*cm. All scans were rated diagnostic with the iDose and iterative model-based reconstructions, whereas 41% of the scans performed with FBP reconstruction were nondiagnostic. With respect to image quality, IMR was superior to iDose and FBP, both in the objective ( P <0.001) and overall subjective ( P ≤0.008) evaluation of the respective data sets. The inter-reviewer agreement for overall image quality was “almost perfect” for IMR, “substantial” for iDose and “moderate” for FBP (κ values of 1.0, 0.6 and 0.46, respectively). Conclusion: Using iterative image reconstruction algorithms, LDCT of urolithiasis is feasible in overweight patients with a BMI between 25 and 35 kg/m 2 . Due to higher image quality, IMR is the preferred algorithm for scan reconstruction as it may help to avoid repeated examinations due to initial nondiagnostic scans.

CO2-CTA with high-pitch CT was feasible in a limited number of patients. Image-quality scores were on average higher for CO2-CTA than for CO2-FLA, while limited imaging quality in the vessels below the knee needs further work on the CT protocol. An added value of cross-sectional imaging was apparent but needs further quantification.