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Objective: To assess the clinical feasibility and validity of fetal magnetic resonance imaging (MRI)-based three-dimensional (3D) reconstruction to locate, classify and quantify diaphragmatic defects in congenital diaphragmatic hernia (CDH).Methods: This retrospective study included 46 cases of CDH which underwent a total of 69 fetal MRI scans (65 in-vivo and four postmortem) at the Medical University of Vienna during the period 1 January 2002 to 1 January 2017. Scans were performed between 16 and 38 gestational weeks using steady-state free precession, T2-weighted and T1-weighted sequences. MRI data were retrieved from the hospital database and manual segmentation of the diaphragm was performed with the open-source software, ITK-SNAP. The resulting 3D models of the fetal diaphragm and its defect(s) were validated by postmortem MRI segmentation and/or comparison of 3D model-based classification of the defect with a reference classification based on autopsy and/or surgery reports. Surface areas of the intact diaphragm and of the defect were measured and used to calculate defect-diaphragmatic ratios (DDR). The need for prosthetic patch repair and, in cases with repeated in-vivo fetal MRI scans, diaphragm growth dynamics, were analyzed based on DDR.Results: Fetal MRI-based manual segmentation of the diaphragm in CDH was feasible for all 65 (100%) of the in-vivo fetal MRI scans. Based on the 3D diaphragmatic models, one bilateral and 45 unilateral defects (n = 47) were further classified as posterolateral (23/47, 48.9%), lateral (7/47, 14.9%) or hemidiaphragmatic (17/47, 36.2%) defects, and none (0%) was classified as anterolateral. This classification of defect location was correct in all 37 (100%) of the cases in which this information could be verified. Nineteen cases had a follow-up fetal MRI scan; in five (26.3%) of these, the initial CDH classification was altered by the results of the second scan. Thirty-three fetuses underwent postnatal diaphragmatic surgical repair; 20 fetuses (all of those with DDR ≥ 54 and 88% of those with DDR > 30) received a diaphragmatic patch, while the other 13 underwent primary surgical repair. Individual DDRs at initial and at follow-up in-vivo fetal MRI correlated significantly (P < 0.001).Conclusions: MRI-based 3D reconstruction of the fetal diaphragm in CDH has been validated to visualize, locate, classify and quantify the defect. Planning of postnatal surgery may be optimized by MRI-based prediction of the necessity for patch placement and the ability to personalize patch design based on 3D-printable templates. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Background and Purpose: The radiologic evaluation of ongoing myelination is currently limited prenatally. Novel quantitative MR imaging modalities provide relaxometric properties that are linked to myelinogenesis. In this retrospective postmortem imaging study, the capability of Synthetic MR imaging and MR fingerprinting-derived relaxometry for tracking fetal myelin development was investigated. Moreover, the consistency of results for both MR approaches was analyzed., Materials and Methods: In 26 cases, quantitative postmortem fetal brain MR data were available (gestational age range, 15 + 1 to 32 + 1; female/male ratio, 14/12). Relaxometric measurements (T1-/T2-relexation times) were determined in the medulla oblongata and the midbrain using Synthetic MR imaging/MR fingerprinting-specific postprocessing procedures (Synthetic MR imaging and MR Robust Quantitative Tool for MR fingerprinting). The Pearson correlations were applied to detect relationships between T1-relaxation times/T2-relaxation times metrics and gestational age at MR imaging. Intraclass correlation coefficients were calculated to assess the consistency of the results provided by both modalities., Results: Both modalities provided quantitative data that revealed negative correlations with gestational age at MR imaging: Synthetic MR imaging-derived relaxation times (medulla oblongata [ r = -0.459; P  = .021]; midbrain [ r = -0.413; P  = .040]), T2-relaxation times (medulla oblongata [ r = -0.625; P  < .001]; midbrain [ r = -0.571; P  = .003]), and MR fingerprinting-derived T1-relaxation times (medulla oblongata [ r = -0.433; P  = .035]; midbrain [ r = -0.386; P  = .062]), and T2-relaxation times (medulla oblongata [ r =-0.883; P  < .001]; midbrain [ r = -0.890; P  < .001]).The intraclass correlation coefficient analysis for result consistency between both MR approaches ranged between 0.661 (95% CI, 0.351-0.841) (T2-relaxation times: medulla oblongata) and 0.920 (95% CI, 0.82-0.965) (T1-relaxation times: midbrain)., Conclusions: There is a good-to-excellent consistency between postmortem Synthetic MR imaging and MR fingerprinting myelin quantifications in fetal brains older than 15 + 1 gestational age. The strong correlations between quantitative myelin metrics and gestational age indicate the potential of quantitative MR imaging to identify delayed or abnormal states of myelination at prenatal stages of cerebral development., (© 2024 by American Journal of Neuroradiology.)

BACKGROUND. Prior work has shown improved image quality for photon-counting detector (PCD) CT of the lungs compared with energy-integrating detector CT. A paucity of the literature has compared PCD CT of the lungs using different reconstruction parameters. OBJECTIVE. The purpose of this study is to the compare the image quality of ultra-high-resolution (UHR) PCD CT image sets of the lungs that were reconstructed using different kernels and slice thicknesses. METHODS. This retrospective study included 29 patients (17 women and 12 men; median age, 56 years) who underwent noncontrast chest CT from February 15, 2022, to March 15, 2022, by use of a commercially available PCD CT scanner. All acquisitions used UHR mode (1024 × 1024 matrix). Nine image sets were reconstructed for all combinations of three sharp kernels (BI56, BI60, and BI64) and three slice thicknesses (0.2, 0.4, and 1.0 mm). Three radiologists independently reviewed reconstructions for measures of visualization of pulmonary anatomic structures and pathologies; reader assessments were pooled. Reconstructions were compared with the clinical reference reconstruction (obtained using the BI64 kernel and a 1.0-mm slice thickness [BI64 1.0-mm ]). RESULTS. The median difference in the number of bronchial divisions identified versus the clinical reference reconstruction was higher for reconstructions with BI64 0.4-mm (0.5), BI60 0.4-mm (0.3), BI64 0.2-mm (0.5), and BI60 0.2-mm (0.2) (all p < .05). The median bronchial wall sharpness versus the clinical reference reconstruction was higher for reconstructions with BI64 0.4-mm (0.3) and BI64 0.2-mm (0.3) and was lower for BI56 1.0-mm (-0.7) and BI56 0.4-mm (-0.3) (all p < .05). Median pulmonary fissure sharpness versus the clinical reference reconstruction was higher for reconstructions with BI64 0.4-mm (0.3), BI60 0.4-mm (0.3), BI56 0.4-mm (0.5), BI64 0.2-mm (0.5), BI60 0.2-mm (0.5), and BI56 0.2-mm (0.3) (all p < .05). Median pulmonary vessel sharpness versus the clinical reference reconstruction was lower for reconstructions with BI56 1.0-mm (-0.3), BI60 0.4-mm (-0.3), BI56 0.4-mm (-0.7), BI64 0.2-mm (-0.7), BI60 0.2-mm (-0.7), and BI56 0.2-mm (-0.7). Median lung nodule conspicuity versus the clinical reference reconstruction was lower for reconstructions with BI56 1.0-mm (-0.3) and BI56 0.4-mm (-0.3) (both p < .05). Median conspicuity of all other pathologies versus the clinical reference reconstruction was lower for reconstructions with BI561.0 mm (-0.3), BI56 0.4-mm (-0.3), BI64 0.2-mm (-0.3), BI60 0.2-mm (-0.3), and BI56 0.2-mm (-0.3). Other comparisons among reconstructions were not significant (all p > .05). CONCLUSION. Only the reconstruction using BI64 0.4-mm yielded improved bronchial division identification and bronchial wall and pulmonary fissure sharpness without a loss in pulmonary vessel sharpness or conspicuity of nodules or other pathologies. CLINICAL IMPACT. The findings of this study may guide protocol optimization for UHR PCD CT of the lungs.

Background Photon-counting detector (PCD) CT enables ultra-high-resolution lung imaging and may shed light on morphologic correlates of persistent symptoms after COVID-19. Purpose To compare PCD CT with energy-integrating detector (EID) CT for noninvasive assessment of post-COVID-19 lung abnormalities. Materials and Methods For this prospective study, adult participants with one or more COVID-19-related persisting symptoms (resting or exertional dyspnea, cough, fatigue) underwent same-day EID and PCD CT between April 2022 and June 2022. The 1.0-mm EID CT images and, subsequently, 1.0-, 0.4-, and 0.2-mm PCD CT images were reviewed for the presence of lung abnormalities. Subjective and objective EID and PCD CT image quality were evaluated using a five-point Likert scale (-2 to 2) and lung signal-to-noise ratios (SNRs). Results Twenty participants (mean age, 54 years ± 16 [SD]; 10 men) were included. EID CT showed post-COVID-19 lung abnormalities in 15 of 20 (75%) participants, with a median involvement of 10% of lung volume [IQR, 0%-45%] and 3.5 lobes [IQR, 0-5]. Ground-glass opacities and linear bands (10 of 20 participants [50%] for both) were the most frequent findings at EID CT. PCD CT revealed additional lung abnormalities in 10 of 20 (50%) participants, with the most common being bronchiectasis (10 of 20 [50%]). Subjective image quality was improved for 1.0-mm PCD versus 1.0-mm EID CT images (median, 1; IQR, 1-2; P < .001) and 0.4-mm versus 1.0-mm PCD CT images (median, 1; IQR, 1-1; P < .001) but not for 0.4-mm versus 0.2-mm PCD CT images (median, 0; IQR, 0-0.5; P = .26). PCD CT delivered higher lung SNR versus EID CT for 1.0-mm images (mean difference, 0.53 ± 0.96; P = .03) but lower SNR for 0.4-mm versus 1.0-mm images and 0.2-mm vs 0.4-mm images (-1.52 ± 0.68 [ P < .001] and -1.15 ± 0.43 [ P < .001], respectively). Conclusion Photon-counting detector CT outperformed energy-integrating detector CT in the visualization of subtle post-COVID-19 lung abnormalities and image quality. © RSNA, 2023 Supplemental material is available for this article.

Competing Interests: The authors declare no conflict of interest.

Clinical Issue: Smoking-related interstitial lung diseases are a heterogeneous group of pulmonary abnormalities. The correct diagnosis has prognostic and therapeutic implications. This article introduces the most common smoking-related interstitial lung diseases and describes a structured approach to support the diagnostic workflow., Practical Recommendations: Computed tomography is pivotal in the diagnostic workflow of smoking-related interstitial lung diseases and may reduce the number of unnecessary lung biopsies. To achieve high diagnostic accuracy, a standardized scanning protocol, and a structured assessment approach should be utilized. During inflammatory stages of respiratory bronchiolitis (RB), respiratory bronchiolitis interstitial lung diseases (RB-ILD), and desquamative interstitial pneumonia (DIP), cessation of smoking as well as the use of steroids are the treatment of choice. In case of fibrotic changes (e.g., in idiopathic pulmonary fibrosis [IPF]), antifibrotic therapy with nintedanib and pirfenidone may be used. Patients with suspected smoking-related interstitial lung disease should be discussed in interdisciplinary board meetings., (© 2022. The Author(s).)

Clinical Issue: Diffuse parenchymal lung diseases include a heterogeneous group of diseases of the lung parenchyma, the alveolar spaces, the vessels and the airways, which can be triggered by various pathomechanisms, such as inflammation and fibrotic changes. Since the therapeutic approaches and prognoses differ significantly between the diseases, the correct diagnosis is of fundamental importance. In routine clinical practice, next to the patients' history, the clinical presentation, the laboratory findings and the bronchoscopy, imaging plays a central role in establishing a diagnosis., Practical Recommendations: The diagnosis of diffuse parenchymal lung diseases is an enormous challenge for clinicians, radiologists as well as pathologists and should therefore preferably be carried out in a multidisciplinary setting. Since patients often present with unspecific, respiratory symptoms, chest radiographs are the first imaging method used. Many patterns of diffuse parenchymal lung diseases (e.g., ground-glass opacities and consolidations), their distribution (e.g., cranial-caudal) and the presence of additional findings (e.g., mediastinal lymphadenopathy) are often already detectable on chest X‑rays. However, the imaging reference standard and thus, an integral part of the assessment of diffuse parenchymal lung disease, is the chest HR-CT. In some cases, the pattern of the HR-CT is pathognomonic, in others it is unspecific for a disease, so that further diagnostic steps are necessary., (© 2021. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)