Contamination of CT scanner surfaces with SARS-CoV-2 and infective potential after examination of invasively ventilated, non-invasively ventilated and non-ventilated patients with positive throat swabs: prospective investigation using real-time reverse-transcription PCR and viral cell culture

Background: During the current severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic, computed tomography (CT) has become widely used in patients with suspected or known coronavirus disease 2019 (COVID-19). This prospective observational study in 28 invasively ventilated and 18 non-invasively ventilated patients with confirmed SARS-CoV-2 contamination aims at investigating SARS-CoV-2 contamination of CT scanner surfaces and its infectiousness. Methods: Swab sampling of the CT table and gantry before and after CT examinations was performed. Additionally, the CT ventilation system air grid was wiped off after each examination. Real-time reverse-transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2 RNA (ribonucleic acid) and viral cell culture were performed in the virology core lab. Results: After examination of non-invasively ventilated or non-ventilated patients, SARS-CoV-2 RNA was found in 11.1% (4/36) on patient near surfaces (CT table and gantry) and in 16.7% (3/18) on the CT air grid respectively after examination of invasively ventilated patients in 5.4% (3/56) on CT table and gantry and 7.1% (2/28) on the CT air grid. Surface contamination was more common in non-invasively ventilated or non-ventilated patients with a high viral load who were actively coughing. RT-PCR cycle threshold (Ct) was high (35.96-39.31) in all positive samples and no positive viral cell culture was found. Conclusion: Our study suggests that CT scanner surface contamination with SARS-CoV-2 is considerable and more common after examination of non-invasively ventilated or non-ventilated patients compared to invasively ventilated patients. However, no viral cell culture positivity was found, hence the infectious potential seems low

Vertebral disk morphology of the lumbar spine: a retrospective analysis of collagen-sensitive mapping using dual-energy computed tomography

Objectives: To investigate the diagnostic accuracy of collagen-sensitive maps derived from dual-energy computed tomography (DECT) for the detection of lumbar disk pathologies in a feasibility setting. Materials and methods: We retrospectively reviewed magnetic resonance imaging (MRI), computed tomography (CT), and DECT datasets acquired in patients who underwent periradicular therapy of the lumbar spine from June to December 2019. Three readers scored DECT collagen maps, conventional CT, and MRI for presence, type, and extent of disk pathology. Contingency table analyses were performed to determine diagnostic accuracy using MRI as standard of reference. Interrater agreement within and between imaging modalities was evaluated by computing intraclass correlation coefficients (ICCs) and Cohen’s kappa. Correlation between sum scores of anteroposterior disk displacement was determined by calculation of a paired t test. Results: In 21 disks in 13 patients, DECT had a sensitivity of 0.87 (0.60–0.98) and specificity of 1.00 (0.54–1.00) for the detection of disk pathology. Intermodality agreement for anteroposterior disk displacement was excellent for DECT (ICC 0.963 [0.909–0.985]) and superior to CT (ICC 0.876 [0.691–0.95]). For anteroposterior disk displacement, DECT also showed greater within-modality interrater agreement (ICC 0.820 [0.666–0.916]) compared with CT (ICC 0.624 [0.39–0.808]). Conclusion: Our data suggest that collagen-sensitive imaging has an added benefit, allowing more accurate evaluation of the extent of disk displacement with higher interrater reliability. Thus, DECT could provide useful diagnostic information in patients undergoing CT for other indications or with contraindications to MRI

The Impact of the Laterality on Radiographic Outcomes of the Bernese Periacetabular Osteotomy

The purpose of this study was to compare the pre and postoperative radiographic findings and analyze the complication rate with respect to the laterality in periacetabular osteotomy in right-handed surgeons. Satisfaction rate and radiographic findings were prospectively collected between 2017 and 2019 and retrospectively reviewed. For analysis, all measurements of the CT scans were performed by a musculoskeletal fellowship-trained radiologist. Complications were classified into two categories: perioperative or postoperative. All surgeries were performed by three right-hand dominant hip surgeons. A total of 41 dysplastic hips (25 right and 16 left hips) in 33 patients were included. Postoperatively, a significantly lower acetabular index angle on the left side was observed at -2.6 +/- 4.3 as compared to the right side at 1.6 +/- 6.5 (p < 0.05). The change in Center edge (CE) angle was significantly lower for the left side 13.7 +/- 5.5 degrees than on the right side, measured at 18.4 +/- 7.3 (p < 0.001); however, the overall CE angle was comparable at 38.5 +/- 8.9 degrees without any significant difference between the operated hips (left side at 37.8 +/- 6.1 degrees versus right side at 39.0 +/- 10.3; p = 0.340). No significant differences in other radiographic measurements or surgical time were observed. For complications, the right side was more commonly affected, which may also explain a higher satisfaction rate in patients who were operated on the left hip with 92.3%. The change in lateral CE angle was significantly lower for the left side and the right hip seems to be predisposed to complications, which correlate with a lower satisfaction rate in right-handed surgeons

Age-dependent microstructural changes of the intervertebral disc: a validation of proteoglycan-sensitive spectral CT

Objective: To analyze the two major components of the intervertebral disc (IVD) in an ex vivo phantom, as well as age-related changes in patients. Methods: Collagen and chondroitin sulfate were imaged at different concentrations in agar solution. Age-related changes in disc density were retrospectively analyzed in normal-appearing discs in dual-energy computed tomography (DECT) images from a patient cohort with various spinal pathologies (n = 136). All computed tomography (CT) scans were acquired using single-source DECT at 80 and 135 kVp with automatic exposure calculation. In 136 patients, the attenuation of normal-appearing discs on collagen/chondroitin maps (cMaps) correlated with the patients' age with Pearson's r using standardized regions of interest in the anterior anulus fibrosus (AAF) and nucleus pulposus (NP). Results: DECT collagen mapping revealed concentration-dependent Hounsfield units (HU) of IVD components. For collagen, we found Pearson's r = 0.9610 (95% CI 0.6789-0.9959), p = 0.0023 at 120 kVe, and r = 0.8824 (95% CI 0.2495-0.9871), p = 0.0199 in cMap. For chondroitin sulfate, Pearson's r was 0.9583 (95% CI 0.6603-0.9956), p = 0.0026 at 120 kVp, and r = 0.9646 (95% CI 0.7044-0.9963), p = 0.0019 in cMap. Analysis of normal-appearing IVDs revealed an inverse correlation of density with age in the AAF: Pearson's r = - 0.2294 at 135 kVp (95% CI - 0.4012 to - 0.04203; p=0.0141) and r = - 0.09341 in cMap (95% CI - 0.2777 to 0.09754; p = 0.0003). In the NP, age and density did not correlate significantly at 135 kVp (p = 0.9228) and in cMap (p = 0.3229). Conclusions: DECT-based collagen mapping allows microstructural analysis of the two main intervertebral disc components-collagen and chondroitin sulfate. IVD density declines with age, presumably due to a reduction in collagen and chondroitin sulfate content. Age-related alterations of disc microstructure appear most pronounced in the AAF

The Impact of Hip Dysplasia on CAM Impingement

Predisposing factors for CAM-type femoroacetabular impingement (FAI) include acetabular protrusion and retroversion; however, nothing is known regarding development in dysplastic hips. The purpose of this study was to determine the correlation between CAM-type FAI and developmental dysplastic hips diagnosed using X-ray and rotational computed tomography. In this retrospective study, 52 symptomatic hips were included, with a mean age of 28.8 +/- 7.6 years. The inclusion criteria consisted of consecutive patients who suffered from symptomatic dysplastic or borderline dysplastic hips and underwent a clinical examination, conventional radiographs and rotational computed tomography. Demographics, standard measurements and the rotational alignments were recorded and analyzed between the CAM and nonCAM groups. Among the 52 patients, 19 presented with CAM impingement, whereas, in 33 patients, no signs of CAM impingement were noticed. For demographics, no significant differences between the two groups were identified. On conventional radiography, the acetabular hip index as well as the CE angle for the development of CAM impingement were significantly different compared to the nonCAM group with a CE angle of 21.0 degrees +/- 5.4 degrees vs. 23.7 degrees +/- 5.8 degrees (p = 0.050) and an acetabular hip index of 25.6 +/- 5.7 vs. 21.9 +/- 7.3 (p = 0.031), respectively. Furthermore, a crossing over sign was observed to be more common in the nonCAM group, which is contradictory to the current literature. For rotational alignment, no significant differences were observed. In dysplastic hips, the CAM-type FAI correlated to a lower CE angle and a higher acetabular hip index. In contrast to the current literature, no significant correlations to the torsional alignment or to crossing over signs were observed

Age-dependent microstructural changes of the intervertebral disc: a validation of proteoglycan-sensitive spectral CT

Objective!#!To analyze the two major components of the intervertebral disc (IVD) in an ex vivo phantom, as well as age-related changes in patients.!##!Methods!#!Collagen and chondroitin sulfate were imaged at different concentrations in agar solution. Age-related changes in disc density were retrospectively analyzed in normal-appearing discs in dual-energy computed tomography (DECT) images from a patient cohort with various spinal pathologies (n = 136). All computed tomography (CT) scans were acquired using single-source DECT at 80 and 135 kVp with automatic exposure calculation. In 136 patients, the attenuation of normal-appearing discs on collagen/chondroitin maps (cMaps) correlated with the patients' age with Pearson's r using standardized regions of interest in the anterior anulus fibrosus (AAF) and nucleus pulposus (NP).!##!Results!#!DECT collagen mapping revealed concentration-dependent Hounsfield units (HU) of IVD components. For collagen, we found Pearson's r = 0.9610 (95% CI 0.6789-0.9959), p = 0.0023 at 120 kVe, and r = 0.8824 (95% CI 0.2495-0.9871), p = 0.0199 in cMap. For chondroitin sulfate, Pearson's r was 0.9583 (95% CI 0.6603-0.9956), p = 0.0026 at 120 kVp, and r = 0.9646 (95% CI 0.7044-0.9963), p = 0.0019 in cMap. Analysis of normal-appearing IVDs revealed an inverse correlation of density with age in the AAF: Pearson's r = - 0.2294 at 135 kVp (95% CI - 0.4012 to - 0.04203; p=0.0141) and r = - 0.09341 in cMap (95% CI - 0.2777 to 0.09754; p = 0.0003). In the NP, age and density did not correlate significantly at 135 kVp (p = 0.9228) and in cMap (p = 0.3229).!##!Conclusions!#!DECT-based collagen mapping allows microstructural analysis of the two main intervertebral disc components-collagen and chondroitin sulfate. IVD density declines with age, presumably due to a reduction in collagen and chondroitin sulfate content. Age-related alterations of disc microstructure appear most pronounced in the AAF.!##!Key points!#!• DECT-based collagen mapping allows precise analysis of the two main intervertebral disc components-collagen and chondroitin sulfate. • Intervertebral disc (IVD) density declines with age, presumably due to a reduction in collagen and chondroitin sulfate content. • Age-related alterations of disc microstructure are most pronounced in the anterior anulus fibrosus (AAF)