Acta radiologica
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Background Adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms have the potential to reduce dose while maintaining image quality. Purpose To compare computed tomography (CT) image quality and diagnostic performance among three reconstruction techniques - ASIR, MBIR, and filtered back projection (FBP) - after transcatheter arterial chemoembolization (TACE) of hepatocellular carcinomas (HCC). Material and Methods Of 60 patients that underwent initial TACE for HCCs, half underwent dynamic liver CT with conventional scanning protocol, and the other half with dose reduction to approximately 60% of conventional exposure. ⋯ However, in terms of subjective parameters, such as image blotchiness, artifacts, and overall quality, MBIR was inferior to FBP and ASIR ( P < 0.001). Regarding diagnostic performance, there were no significant differences among reviewers in the detection of viable HCCs depending on the reconstruction algorithm, regardless of the dose reduction protocol ( P > 0.017). Conclusion Although subjective evaluations suggest that MBIR images are of lower quality compared with FBP and ASIR regardless of radiation dosage, there were no significant differences among reconstruction algorithms in diagnosis of viable HCC after TACE.
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Background There has been no comparison study to assess the diagnostic efficacy of additional anterior cruciate ligament (ACL) views in three-dimensional (3D) volume isotropic turbo spin-echo acquisition (VISTA) and two-dimensional (2D) fast spin-echo (FSE) T2-weighted (T2W) images for the diagnosis of ACL tear. Purpose To compare the diagnostic performances of additional ACL views on VISTA with those on the 2D FSE T2W images. Material and Methods This retrospective study included 78 patients who were suspected to have ACL injury and underwent both 2D TSE T2W magnetic resonance imaging (MRI) and 3D VISTA MRI of the knee between November 2012 and March 2013. ⋯ When considering both views of the oblique sagittal and coronal images, the inter-observer agreement between readers nearly concurred. There were no statistically significant differences in the sensitivity, specificity, and accuracy between 2D FSE images and VISTA images. Conclusion The performance of the additional ACL view on 3D VISTA MRI is comparable to that of 2D FSE T2W MRI in the diagnosis of ACL tear though the image quality of the 3D VISTA MRI is not equal to that of 2D FSE MRI.
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Review Multicenter Study
Effects of gadolinium-based contrast agent concentrations (0.5 M or 1.0 M) on the diagnostic performance of magnetic resonance imaging examinations: systematic review of the literature.
Background To date there is no agreement as to what is the optimal concentration for gadolinium-based contrast agents (GBCAs). Purpose To assess whether diagnostic performance differences exist between 0.5 M and 1.0 M GBCAs used for magnetic resonance imaging (MRI). Material and Methods A PubMed literature search identified 21 clinical studies published between 2005 and 2013 which evaluated the diagnostic efficacy of both types of GBCAs. ⋯ Methodological biases were identified in several studies impairing the interpretation of comparisons. Conclusion Imaging differences between 0.5 M and 1.0 M GBCAs were essentially observed under non-equimolar delivery rates. However, they did not result into greater diagnostic efficacy when performed under equimolar conditions.
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Background The superficial white matter (SWM), which fills the space between the deep white matter and the cortex, has not been well characterized. Purpose To determine whether the assessment of the relative signal intensity (SI) of the SWM in the precentral and postcentral gyri on phase difference enhanced (PADRE) images contributes in establishing anatomical landmark. Material and Methods The study population consisted of 43 normal subjects (28 women, 15 men; mean age, 52.9 years; age range, 22-90 years). ⋯ In the SI analyses of the PADRE images, the Grade I, Grade II, and Grade III appearances were found in one (1%), 20 (23%), and 65 (76%) of the 86 precentral gyri (43 subjects), respectively, and in one (1%), 23 (27%), and 62 (72%) of the 86 postcentral gyri, respectively. Conclusion On PADRE images, the perirolandic SWM showed hypointensity compared to other cerebral cortices, which probably reflects differences in the concentrations of the nerve fibers, as well as the higher myelin content. PADRE may be useful for the identification of the central sulcus by assessing the SI of the SWM.
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Background Using imaging techniques to diagnose malignant and inflammatory lesions in the lung can be challenging. Purpose To compare intravoxel incoherent motion (IVIM) and apparent diffusion coefficient (ADC) magnetic resonance imaging (MRI) analysis in their ability to discriminate lung cancer from focal inflammatory lung lesions. Material and Methods Thirty-eight patients with lung masses were included: 30 lung cancers and eight inflammatory lesions. ⋯ By IVIM, f was found to be significantly higher in inflammatory lesions than lung cancer ([46.10 ± 12.92] % vs. [29.29 ± 10.89] %; P = 0.005). There was no difference in D and D* between lung cancer and inflammatory lesions ( P = 0.747 and 0.124, respectively). f showed comparable diagnostic performance with ADC in differentiating lung cancer from inflammatory lung lesions, with areas under the curve of 0.833 and 0.826, sensitivity 80.0% and 73.3%, and specificity 75.0% and 87.5%, respectively. Conclusion The IVIM parameter f value provides comparable diagnostic performance with ADC and could be used as a surrogate marker for differentiating lung cancer from inflammatory lesions.