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Objective: A prerequisite for successful clinical use of functional magnetic resonance imaging (fMRI) is the selection of an appropriate imaging sequence. The aim of this study was to compare 2D and 3D fMRI sequences using different image quality assessment methods.Methods: Descriptive image measures, such as activation volume and temporal signal-to-noise ratio (TSNR), were compared with results from visual grading characteristics (VGC) analysis of the fMRI results.Results: Significant differences in activation volume and TSNR were not directly reflected by differences in VGC scores. The results suggest that better performance on descriptive image measures is not always an indicator of improved diagnostic quality of the fMRI results.Conclusion: In addition to descriptive image measures, it is important to include measures of diagnostic quality when comparing different fMRI data acquisition methods. [ABSTRACT FROM AUTHOR]

Purpose: To determine the effect of tube load, model-based iterative reconstruction (MBIR) strength and slice thickness in abdominal CT using visual comparison of multi-planar reconstruction images., Method: Five image criteria were assessed independently by four radiologists on two data sets at 42- and 98-mAs tube loads for 25 patients examined on a 192-slice dual-source CT scanner. Effect of tube load, MBIR strength, slice thickness and potential dose reduction was estimated with Visual Grading Regression (VGR). Objective image quality was determined by measuring noise (SD), contrast-to-noise (CNR) ratio and noise-power spectra (NPS)., Results: Comparing 42- and 98-mAs tube loads, improved image quality was observed as a strong effect of log tube load regardless of MBIR strength (p < 0.001). Comparing strength 5 to 3, better image quality was obtained for two criteria (p < 0.01), but inferior for liver parenchyma and overall image quality. Image quality was significantly better for slice thicknesses of 2mm and 3mm compared to 1mm, with potential dose reductions between 24%-41%. As expected, with decrease in slice thickness and algorithm strength, the noise power and SD (HU-values) increased, while the CNR decreased., Conclusion: Increasing slice thickness from 1 mm to 2 mm or 3 mm allows for a possible dose reduction. MBIR strength 5 shows improved image quality for three out of five criteria for 1 mm slice thickness. Increasing MBIR strength from 3 to 5 has diverse effects on image quality. Our findings do not support a general recommendation to replace strength 3 by strength 5 in clinical abdominal CT protocols. However, strength 5 may be used in task-based protocols., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Our aim was to compare CT images from native, nephrographic and excretory phases using image quality criteria as well as the detection of positive pathological findings in CT Urography, to explore if the radiation burden to the younger group of patients or patients with negative outcomes can be reduced., Methods: This is a retrospective study of 40 patients who underwent a CT Urography examination on a 192-slice dual source scanner. Image quality was assessed for four specific renal image criteria from the European guidelines, together with pathological assessment in three categories: renal, other abdominal, and incidental findings without clinical significance. Each phase was assessed individually by three radiologists with varying experience using a graded scale. Certainty scores were derived based on the graded assessments. Statistical analysis was performed using visual grading regression (VGR). The limit for significance was set at p = 0.05., Results: For visual reproduction of the renal parenchyma and renal arteries, the image quality was judged better for the nephrogram phase (p < 0.001), whereas renal pelvis/calyces and proximal ureters were better reproduced in the excretory phase compared to the native phase (p < 0.001). Similarly, significantly higher certainty scores were obtained in the nephrogram phase for renal parenchyma and renal arteries, but in the excretory phase for renal pelvis/calyxes and proximal ureters. Assessment of pathology in the three categories showed no statistically significant differences between the three phases. Certainty scores for assessment of pathology, however, showed a significantly higher certainty for renal pathology when comparing the native phase to nephrogram and excretory phase and a significantly higher score for nephrographic phase but only for incidental findings., Conclusion: Visualisation of renal anatomy was as expected with each post-contrast phase showing favourable scores compared to the native phase. No statistically significant differences in the assessment of pathology were found between the three phases. The low-dose CT (LDCT) seems to be sufficient in differentiating between normal and pathological examinations. To reduce the radiation burden in certain patient groups, the LDCT could be considered a suitable alternative as a first line imaging method. However, radiologists should be aware of its limitations.

Purpose: To estimate potential dose reduction in abdominal CT by visually comparing images reconstructed with filtered back projection (FBP) and strengths of 3 and 5 of a specific MBIR., Material and Methods: A dual-source scanner was used to obtain three data sets each for 50 recruited patients with 30, 70 and 100% tube loads (mean CTDI vol 1.9, 3.4 and 6.2 mGy). Six image criteria were assessed independently by five radiologists. Potential dose reduction was estimated with Visual Grading Regression (VGR)., Results: Comparing 30 and 70% tube load, improved image quality was observed as a significant strong effect of log tube load and reconstruction method with potential dose reduction relative to FBP of 22-47% for MBIR strength 3 (p < 0.001). For MBIR strength 5 no dose reduction was possible for image criteria 1 (liver parenchyma), but dose reduction between 34 and 74% was achieved for other criteria. Interobserver reliability showed agreement of 71-76% (κ w 0.201-0.286) and intra-observer reliability of 82-96% (κ w 0.525-0.783)., Conclusion: MBIR showed improved image quality compared to FBP with positive correlation between MBIR strength and increasing potential dose reduction for all but one image criterion., Key Points: • MBIR's main advantage is its de-noising properties, which facilitates dose reduction. • MBIR allows for potential dose reduction in relation to FBP. • Visual Grading Regression (VGR) produces direct numerical estimates of potential dose reduction. • MBIR strengths 3 and 5 dose reductions were 22-34 and 34-74%. • MBIR strength 5 demonstrates inferior performance for liver parenchyma.

Oesophageal emptying was studied with scintigraphy, radiography, and the acid clearing test (ACT) in 18 patients reporting dysphagia and previously operated on with fundoplication. Radiography with contrast medium, isodense with water, revealed abnormalities in either motility or emptying capacity in 39% (7/18). A A barium meal showed abnormalities--that is, a tight repair, disruption of the fundoplication, or recurrence of the hernia--in 56% (10/18). The ACT was prolonged in 40% (6/15) of the patients. Pathological findings at scintigraphy with a solid bolus were found in 67% (12/18). Even if scintigraphy with a solid bolus is the method that identifies the highest number of patients with impaired oesophageal function among the tests used, it cannot differentiate between functional and anatomical disorders. A barium meal examination is the method of choice when an anatomical disorder is suspected.

Amyloidosis of the larynx is a rare disease, accounting for less than 1% of all benign laryngeal 'tumours'. Three cases of this type of lesion are reported--one of the vocal cord, one of the false vocal cord and one of the subglottis and trachea. In 2 of the patients the amyloidosis was localized, while the third was later found also to have an epipharyngeal solitary plasmacytoma with amyloid deposits and in addition amyloidosis of the nasal cavity. However, the amyloidosis in this patient may still be regarded as being localized, as the clinical examination and laboratory tests afforded no evidence of generalized disease. Amyloidosis of the larynx may be manifested as a localized tumour or as a diffuse infiltration. The symptoms and signs will, of course, depend on the site of the amyloid deposit. When the vocal cords are involved hoarseness may result, and this was the most prominent sign in the present cases. The treatment of laryngeal amyloidosis is primarily by endoscopic excision. Amyloid substance has specific staining properties. The Congo red reaction with a green birefringence in polarized light and Phorwhite BBU using fluorescence microscopy are regarded as the most reliable staining reactions. Electron microscopy has revealed a typical fibrillar structure of amyloid.