Diagnostic value of "hyperdense consolidation sign" as a characteristic new computed tomography sign of diffuse alveolar hemorrhage.

Diffuse alveolar hemorrhage (DAH) is an uncommon but life-threatening condition. Although DAH must be distinguished from other lung diseases, no specific computed tomography (CT) signs of DAH have been reported. This study aimed to evaluate the diagnostic value of "hyperdense consolidation" CT sign. We retrospectively evaluated non-contrast CT findings of 25 DAH patients and age- (≤ 2 years) and sex-matched controls with symptoms of dyspnea and hypoxemia. Two radiologists compared the two groups for the presence of hyperdense consolidation signs in lung parenchyma, defined as consolidation that visually contains areas with higher density than the aorta in the specific narrow window setting (window level = 35 Hounsfield units [HU], width = 80 HU) with a mediastinal filter. The sensitivity, specificity, positive- and negative-predictive values of the hyperdense consolidation sign for detection of DAH were 32.0%, 100%, 100%, and 59.5% with perfect interobserver agreement (к = 1.00). The hyperdense consolidation sign was found to be a highly specific sign for DAH.

Synthetic double inversion recovery imaging in brain MRI: quantitative evaluation and feasibility of synthetic MRI and a comparison with conventional double inversion recovery and fluid-attenuated inversion recovery sequences.

BACKGROUND AND PURPOSE: Synthetic MR imaging (SyMRI) allows the reconstruction of various contrast images, including double inversion recovery (DIR), from a single scan. This study aimed to investigate the advantages of SyMRI by comparing synthetic DIR images with synthetic T2-weighted fluid-attenuated inversion recovery (T2W-FLAIR) and conventional DIR images. MATERIALS AND METHODS: We retrospectively reviewed the imaging data of 100 consecutive patients who underwent brain MRI between December 2018 and March 2019. Synthetic DIR, T2W-FLAIR, T1-weighted, and phase-sensitive inversion recovery (PSIR) images were generated from SyMRI data. For synthetic DIR, the two inversion times required to suppress white matter and cerebrospinal fluid (CSF) were manually determined by two radiologists. Quantitative analysis was performed by manually tracing the region of interest (ROI) at the sites of the lesion, white matter, and CSF. Synthetic DIR, synthetic T2W-FLAIR, and conventional DIR images were compared on the basis of using the gray matter-to-white matter, lesion-to-white matter, and lesion-to-CSF contrast-to-noise ratios. RESULTS: The two radiologists showed no differences in setting inversion time (TI) values, and their evaluations showed excellent interobserver agreement. The mean signal intensities obtained with synthetic DIR were significantly higher than those obtained with synthetic T2W-FLAIR and conventional DIR. CONCLUSION: Synthetic DIR images showed a higher contrast than synthetic T2WFLAIR and conventional DIR images.

Breakthrough reactions of iodinated and gadolinium contrast media after oral steroid premedication protocol.

BACKGROUND: Adverse reactions to iodinated and gadolinium contrast media are an important clinical issue. Although some guidelines have proposed oral steroid premedication protocols to prevent adverse reactions, some patients may have reactions to contrast media in spite of premedication (breakthrough reaction; BTR).The purpose of this study was to assess the frequency, type and severity of BTR when following an oral steroid premedication protocol. METHODS: All iodinated and gadolinium contrast-enhanced radiologic examinations between August 2011 and February 2013 for which the premedication protocol was applied in our institution were assessed for BTRs. RESULTS: The protocol was applied to a total of 252 examinations (153 patients, ages 15-87 years; 63 males, 90 females). Of these, 152 were for prior acute adverse reactions to contrast media, 85 were for a history of bronchial asthma, and 15 were for other reasons. There were 198 contrast enhanced CTs and 54 contrast enhanced MRIs. There were nine BTR (4.5%) for iodinated contrast media, and only one BTR (1.9%) for gadolinium contrast media: eight were mild and one was moderate. No patient who had a mild index reaction (IR) had a severe BTR. CONCLUSION: Incidence of BTRs when following the premedication protocol was low. This study by no means proves the efficacy of premedication, but provides some support for following a premedication protocol to improve safety of contrast-enhanced examinations when prior adverse reactions are mild, or when there is a history of asthma.