Head-to-Head Comparison of Dual-Source and Split-Beam Filter Multi-Energy CT versus SPECT/CT for Assessing Lobar Lung Perfusion in Emphysema

Purpose

To evaluate dual-source and split-beam filter multi-energy chest CT in assessing pulmonary perfusion on a lobar level in patients with lung emphysema, using perfusion SPECT as the reference standard.

Materials and Methods

Patients with emphysema evaluated for lung volume reduction therapy between May 2016 and February 2021 were retrospectively included. All patients underwent SPECT and either dual-source or split-beam filter (SBF) multi-energy CT. To calculate the fractional lobar lung perfusion (FLLP), SPECT acquisitions were co-registered with chest CT scans (hereafter, SPECT/CT) and semi-manually segmented. For multi-energy CT scans, lung lobes were automatically segmented using a U-Net model. Segmentations were manually verified. The FLLP was derived from iodine maps computed from the multi-energy data. Statistical analysis included Pearson and intraclass correlation coefficients and Bland-Altman analysis.

Results

Fifty-nine patients (30 male, 29 female; 31 underwent dual-source CT, 28 underwent SBF CT; mean age for all patients, 67 years ± 8 [SD]) were included. Both multi-energy methods significantly correlated with the SPECT/CT acquisitions for all individual lobes (P < .001). Pearson correlation concerning all lobes combined was significantly better for dual-source (r = 0.88) than for SBF multi-energy CT (r = 0.78; P = .006). On the level of single lobes, Pearson correlation coefficient differed for the right upper lobe only (dual-source CT, r = 0.88; SBF CT, r = 0.58; P = .008).

Conclusion

Dual-source and SBF multi-energy CT accurately assessed lung perfusion on a lobar level in patients with emphysema compared with SPECT/CT. The overall correlation was higher for dual-source multi-energy CT.Keywords: Chronic Obstructive Pulmonary Disease, Comparative Studies, Computer Applications, CT Spectral Imaging, Image Postprocessing, Lung, Pulmonary Perfusion© RSNA, 2023.

CT findings in "Post-Covid": residua from acute pneumonia or "Post-Covid-ILD"?

The aim of this study was to evaluate if CT findings in patients with pulmonary Post Covid syndrome represent residua after acute pneumonia or if SARS-CoV 2 induces a true ILD. Consecutive patients with status post acute Covid-19 pneumonia and persisting pulmonary symptoms were enrolled. Inclusion criteria were availability of at least one chest CT performed in the acute phase and at least one chest CT performed at least 80 days after symptom onset. In both acute and chronic phase CTs 14 CT features as well as distribution and extent of opacifications were independently determined by two chest radiologists. Evolution of every single CT lesion over time was registered intraindividually for every patient. Moreover, lung abnormalities were automatically segmented using a pre-trained nnU-Net model and volume as well as density of parenchymal lesions were plotted over the entire course of disease including all available CTs. 29 patients (median age 59 years, IQR 8, 22 men) were enrolled. Follow-up period was 80-242 days (mean 134). 152/157 (97 %) lesions in the chronic phase CTs represented residua of lung pathology in the acute phase. Subjective and objective evaluation of serial CTs showed that CT abnormalities were stable in location and continuously decreasing in extent and density. The results of our study support the hypothesis that CT abnormalities in the chronic phase after Covid-19 pneumonia represent residua in terms of prolonged healing of acute infection. We did not find any evidence for a Post Covid ILD.

Combined Model of Quantitative Evaluation of Chest Computed Tomography and Laboratory Values for Assessing the Prognosis of Coronavirus Disease 2019

PURPOSE

 To assess the prognostic power of quantitative analysis of chest CT, laboratory values, and their combination in COVID-19 pneumonia.

MATERIALS AND METHODS

 Retrospective analysis of patients with PCR-confirmed COVID-19 pneumonia and chest CT performed between March 07 and November 13, 2020. Volume and percentage (PO) of lung opacifications and mean HU of the whole lung were quantified using prototype software. 13 laboratory values were collected. Negative outcome was defined as death, ICU admittance, mechanical ventilation, or extracorporeal membrane oxygenation. Positive outcome was defined as care in the regular ward or discharge. Logistic regression was performed to evaluate the prognostic value of CT parameters and laboratory values. Independent predictors were combined to establish a scoring system for prediction of prognosis. This score was validated on a separate validation cohort.

RESULTS

 89 patients were included for model development between March 07 and April 27, 2020 (mean age: 60.3 years). 38 patients experienced a negative outcome. In univariate regression analysis, all quantitative CT parameters as well as C-reactive protein (CRP), relative lymphocyte count (RLC), troponin, and LDH were associated with a negative outcome. In a multivariate regression analysis, PO, CRP, and RLC were independent predictors of a negative outcome. Combination of these three values showed a strong predictive value with a C-index of 0.87. A scoring system was established which categorized patients into 4 groups with a risk of 7 %, 30 %, 67 %, or 100 % for a negative outcome. The validation cohort consisted of 28 patients between May 5 and November 13, 2020. A negative outcome occurred in 6 % of patients with a score of 0, 50 % with a score of 1, and 100 % with a score of 2 or 3.

CONCLUSION

 The combination of PO, CRP, and RLC showed a high predictive value for a negative outcome. A 4-point scoring system based on these findings allows easy risk stratification in the clinical routine and performed exceptionally in the validation cohort.

KEY POINTS

  · A high PO is associated with an unfavorable outcome in COVID-19. · PO, CRP, and RLC are independent predictors of an unfavorable outcome, and their combination has strong predictive power. · A 4-point scoring system based on these values allows quick risk stratification in a clinical setting.

CITATION FORMAT

· Scharf G, Meiler S, Zeman F et al. Combined Model of Quantitative Evaluation of Chest Computed Tomography and Laboratory Values for Assessing the Prognosis of Coronavirus Disease 2019. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1731-7905.

Severe COVID-19 pneumonia: Perfusion analysis in correlation with pulmonary embolism and vessel enlargement using dual-energy CT data

BACKGROUND

Gas exchange in COVID-19 pneumonia is impaired and vessel obstruction has been suspected to cause ventilation-perfusion mismatch. Dual-energy CT (DECT) can depict pulmonary perfusion by regional assessment of iodine uptake.

OBJECTIVE

The purpose of this study was the analysis of pulmonary perfusion using dual-energy CT in a cohort of 27 consecutive patients with severe COVID-19 pneumonia.

METHOD

We retrospectively analyzed pulmonary perfusion with DECT in 27 consecutive patients (mean age 57 years, range 21-73; 19 men and 8 women) with severe COVID-19 pneumonia. Iodine uptake (IU) in regions-of-interest placed into normally aerated lung, ground-glass opacifications (GGO) and consolidations was measured using a dedicated postprocessing software. Vessel enlargement (VE) within opacifications and presence of pulmonary embolism (PE) was assessed by subjective analysis. Linear mixed models were used for statistical analyses.

RESULTS

Compared to normally aerated lung 106/151 (70.2%) opacifications without upstream PE demonstrated an increased IU, 9/151 (6.0%) an equal IU and 36/151 (23.8%) a decreased IU. The estimated mean iodine uptake (EMIU) in opacifications without upstream PE (GGO 1.77 mg/mL; 95%-CI: 1.52-2.02; p = 0.011, consolidations 1.82 mg/mL; 95%-CI: 1.56-2.08, p = 0.006) was significantly higher compared to normal lung (1.22 mg/mL; 95%-CI: 0.95-1.49). In case of upstream PE, EMIU of opacifications (combined GGO and consolidations) was significantly decreased compared to normal lung (0.52 mg/mL; 95%-CI: -0.07-1.12; p = 0.043). The presence of VE in opacifications correlated significantly with iodine uptake (p<0.001).

CONCLUSIONS

DECT revealed the opacifications in a subset of patients with severe COVID-19 pneumonia to be perfused non-uniformly with some being hypo- and others being hyperperfused. Mean iodine uptake in opacifications (both ground-glass and consolidation) was higher compared to normally aerated lung except for areas with upstream pulmonary embolism. Vessel enlargement correlated with iodine uptake: In summary, in a cohort of 27 consecutive patients with severe COVID-19 pneumonia, dual-energy CT demonstrated a wide range of iodine uptake in pulmonary ground-glass opacifications and consolidations as a surrogate marker for hypo- and hyperperfusion compared to normally aerated lung. Applying DECT to determine which pathophysiology is predominant might help to tailor therapy to the individual patient´s needs.

CT Features of COVID-19 Pneumonia Differ Depending on the Severity and Duration of Disease

BACKGROUND

CT is important in the care of patients with COVID-19 pneumonia. However, CT morphology can change significantly over the course of the disease. To evaluate the CT morphology of RT-PCR-proven COVID-19 pneumonia in a German cohort with special emphasis on identification of potential differences of CT features depending on duration and severity of disease.

METHOD

All patients with RT-PCR-proven COVID-19 pneumonia and chest CT performed between March 1 and April 15, 2020 were retrospectively identified. The CT scans were evaluated regarding the presence of different CT features (e. g. ground glass opacity, consolidation, crazy paving, vessel enlargement, shape, and margin of opacifications), distribution of lesions in the lung and extent of parenchymal involvement. For subgroup analyses the patients were divided according to the percentage of parenchymal opacification (0-33 %, 34-66 %, 67-100 %) and according to time interval between symptom onset and CT date (0-5 d, 6-10 d, 11-15 d, > 15 d). Differences in CT features and distribution between subgroups were tested using the Mantel-Haenszel Chi Squared for trend.

RESULTS

The frequency of CT features (ground glass opacity, consolidation, crazy paving, bronchial dilatation, vessel enlargement, lymphadenopathy, pleural effusion) as well as pattern of parenchymal involvement differed significantly depending on the duration of disease and extent of parenchymal involvement. The early phase of disease was characterized by GGO and to a lesser extent consolidation. The opacifications tended to be round and to some extent with sharp margins and a geographic configuration. The vessels within/around the opacifications were frequently dilated. Later on, the frequency of consolidation and especially crazy paving increased, and the round/geographic shape faded. After day 15, bronchial dilatation occurred, and lymphadenopathy and pleural effusion were seen more frequently than before.

CONCLUSION

The prevalence of CT features varied considerably during the course of disease and depending on the severity of parenchymal involvement. Radiologists should take into account the time interval between symptom onset and date of CT and the severity of disease when discussing the likelihood of COVID-19 pneumonia based on CT morphology.

KEY POINTS

· The frequency of CT features and pattern of parenchymal involvement vary depending on the duration and extent of COVID-19 pneumonia.. · The early phase is characterized by GGO and consolidation which demonstrate a round shape and at least to some extent have sharp margins and a geographic configuration.. · The frequency of consolidation and especially crazy paving increases during the course of disease.. · Beyond day 15 after symptom onset, bronchial dilatation occurs.. · Radiologists should take into account the duration and severity of disease when considering COVID-19 pneumonia..

CITATION FORMAT

· Schaible J, Meiler S, Poschenrieder F et al. CT Features of COVID-19 Pneumonia Differ Depending on the Severity and Duration of Disease. Fortschr Röntgenstr 2021; 193: 672 - 682.

Computed tomography characterization and outcome evaluation of COVID-19 pneumonia complicated by venous thromboembolism

BACKGROUND

COVID-19 is frequently complicated by venous thromboembolism (VTE). Computed tomography (CT) of the chest-primarily usually conducted as low-dose, non-contrast enhanced CT-plays an important role in the diagnosis and follow-up of COVID-19 pneumonia. Performed as contrast-enhanced CT pulmonary angiography, it can reliably detect or rule-out pulmonary embolism (PE). Several imaging characteristics of COVID-19 pneumonia have been described for chest CT, but no study evaluated CT findings in the context of VTE/PE.

PURPOSE

In our retrospective study, we analyzed clinical, laboratory and CT imaging characteristics of 50 consecutive patients with RT-PCR proven COVID-19 pneumonia who underwent contrast-enhanced chest CT at two tertiary care medical centers.

MATERIAL AND METHODS

All patients with RT-PCR proven COVID-19 pneumonia and contrast-enhanced chest CT performed at two tertiary care hospitals between March 1st and April 20th 2020 were retrospectively identified. Patient characteristics (age, gender, comorbidities), symptoms, date of symptom onset, RT-PCR results, imaging results of CT and leg ultrasound, laboratory findings (C-reactive protein, differential blood count, troponine, N-terminal pro-B-type natriuretic peptide (NT-proBNP), fibrinogen, interleukin-6, D-dimer, lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase muscle-brain (CKmb) and lactate,) and patient outcome (positive: discharge or treatment on normal ward; negative: treatment on intensive care unit (ICU), need for mechanical ventilation, extracorporeal membrane oxygenation (ECMO), or death) were analyzed. Follow-up was performed until May 10th. Patients were assigned to two groups according to two endpoints: venous thromboembolism (VTE) or no VTE. For statistical analysis, univariate logistic regression models were calculated.

RESULTS

This study includes 50 patients. In 14 out of 50 patients (28%), pulmonary embolism was detected at contrast-enhanced chest CT. The majority of PE was detected on CTs performed on day 11-20 after symptom onset. Two patients (14%) with PE simultaneously had evidence of deep vein thrombosis. 15 patients (30%) had a negative outcome (need for intensive care, mechanical ventilation, extracorporeal membrane oxygenation, or death), and 35 patients (70%) had a positive outcome (transfer to regular ward, or discharge). Patients suffering VTE had a statistically significant higher risk of an unfavorable outcome (p = 0.028). In univariate analysis, two imaging characteristics on chest CT were associated with VTE: crazy paving pattern (p = 0.024) and air bronchogram (n = 0.021). Also, elevated levels of NT-pro BNP (p = 0.043), CK (p = 0.023) and D-dimers (p = 0.035) were significantly correlated with VTE.

CONCLUSION

COVID-19 pneumonia is frequently complicated by pulmonary embolism (incidence of 28% in our cohort), remarkably with lacking evidence of deep vein thrombosis in nearly all thus affected patients of our cohort. As patients suffering VTE had an adverse outcome, we call for a high level of alertness for PE and advocate a lower threshold for contrast-enhanced CT in COVID-19 pneumonia. According to our observations, this might be particularly justified in the second week of disease and if a crazy paving pattern and / or air bronchogram is present on previous non-enhanced CT.

Can CT performed in the early disease phase predict outcome of patients with COVID 19 pneumonia? Analysis of a cohort of 64 patients from Germany

PURPOSE

The aim of this study was to investigate if CT performed in the early disease phase can predict the course of COVID-19 pneumonia in a German cohort.

METHOD

All patients with RT-PCR proven COVID-19 pneumonia and chest CT performed within 10 days of symptom onset between March 1st and April 15th 2020 were retrospectively identified from two tertiary care hospitals. 12 CT features, their distribution in the lung and the global extent of opacifications were evaluated. For analysis of prognosis two compound outcomes were defined: positive outcome was defined as either discharge or regular ward care; negative outcome was defined as need for mechanical ventilation, treatment on intensive care unit, extracorporeal membrane oxygenation or death. Follow-up was performed until June 19th. For statistical analysis uni- und multivariable logistic regression models were calculated.

RESULTS

64 patients were included in the study. By univariable analysis the following parameters predicted a negative outcome: consolidation (p = 0.034), crazy paving (p = 0.004), geographic shape of opacification (p = 0.022), dilatation of bronchi (p = 0.002), air bronchogram (p = 0.013), vessel enlargement (p = 0.014), pleural effusion (p = 0.05), bilateral disease (p = 0.004), involvement of the upper lobes (p = 0.004, p = 0.015) or the right middle lobe (p < 0.001) and severe extent of opacifications (p = 0.002). Multivariable analysis revealed crazy paving and severe extent of parenchymal involvement to be independently predictive for a poor outcome.

CONCLUSIONS

Easy to assess CT features in the early phase of disease independently predicted an adverse outcome of patients with COVID-19 pneumonia.

Sharp margin and geographic shape: systematic evaluation of two novel CT features in COVID-19 pneumonia

OBJECTIVE

CT is important in the care of patients with COVID-19 pneumonia. However, specificity might be poor in the absence of a clinical and epidemiological context. The goal of this work was to systematically evaluate two novel CT features (sharp margin and geographic shape) of COVID-19 pneumonia.

METHODS

All patients with reverse transcription polymerase chain reaction proven COVID-19 pneumonia and chest CT between March first and April 15, 2020 were retrospectively identified from two tertiary care hospitals in Germany. The CTs were evaluated regarding the presence of typical CT signs (e.g. ground glass opacitiy, consolidation, crazy paving). Moreover, the shape of the opacifications (round, geographic, curvilinear) and their margin (unsharp, sharp) was determined.

RESULTS

The study population comprised 108 patients (64 male) with a mean age of 59.6 years. Ground glass opacities (96%) and consolidation (75%) were the most prevalent CT signs. Crazy paving was seen in 17%, bronchial dilatation in 21%, air bronchogram in 29%, vessel enlargement in 47%, cavitation in 0%, lymphadenopathy in 32%, pleural effusion in 16%. Round configuration of densities was present in 41% of CTs, geographic shape in 27% and curvilinear opacities in 44%. 79% of opacifications were at least partially sharply marginated. In almost all cases, the lung was affected bilaterally (94%).

CONCLUSION

The CT pattern of COVID-19 pneumonia in a cohort from Germany was in accordance with prior studies. However, we identified two novel CT signs of COVID-19 pneumonia which have so far not been systematically evaluated. A sharp border and geographic shape of opacifications were frequently observed.

ADVANCES IN KNOWLEDGE

The newly described CT features "sharp margin" and "geographic shape" of opacifications in patients with COVID-19 pneumonia might help to increase specificity of CT.

Subjective quality of life and sexual functioning after germ-cell tumour therapy

PURPOSE

To evaluate the influence of germ-cell tumour therapy on sexual functioning and subjective quality of life (QL). To investigate the communication about sexual problems between patients, their partners, and doctors. In all, 474 patients treated for germ-cell tumours at the Department of Internal Medicine III, Ludwig-Maximilians-University Munich, from 1979 to 2000 were asked to complete a self-report questionnaire concerning psychosocial dimensions and subjective QL (QLS; Henrich and Herschbach, 2000). In total, 341 patients returned a completed questionnaire (response rate, 71.9%). The median age at survey was 41.9 years and the median follow-up period after therapy was 9.6 years. Persisting sexual sequelae were lower than in the current literature: decreased sexual desire (7.1%), erection (10.0%), orgasm (10.2%), ejaculation (28.8%), sexual activity (8.5%), and sexual satisfaction (4.8%). In QL the satisfaction with 'friends/acquaintances' (P<0.001) and 'family life/children' (P<0.001), is lower than in the healthy population. Correlations between functional scales and subjective QL were highly significant. There is a strong correlation between sexual satisfaction and global life satisfaction (Spearman's Rho: 0.48; P<0.01). A total of 61.4% of patients were not offered communication about sexual problems by their doctors and 21.2% were unable to talk with their partner about sexual issues. In conclusion, moderating psychosocial variables (e.g. personality factors, cognitive processes) should be investigated to clarify the relationship between life satisfaction (subjective QL) and functional impairments. Communication about sexual problems should be offered as a standard to patients treated for germ-cell tumours.