CT Density Research Articles

Evaluation of disease severity with quantitative chest CT in COVID-19 patients.

We aimed to assess the severity of coronavirus disease 2019 (COVID-19) pneumonia on computed tomography (CT) using quantitative (QCT) and semiquantitative (SCT) assessments and compare with the clinical findings. Two observers independently examined the CT images of COVID-19 patients, and the SCT severity score was calculated. The SCT score was calculated as the sum of values ranging from 0 to 4, according to the volumetric rate of involvement for each lung lobe. In quantitative assessment, total lung volume (TLV) was automatically calculated from CT density values between -200 and -950 HU. Besides, healthy lung volume (HLV) was calculated from voxels between -800 and -950 HU. The QCT score was calculated with the following formula: (TLV - HLV / TLV) ×100. All patients were clinically divided into four groups: mild, common, severe, and critical. Interobserver agreement for SCT assessment was investigated using the Cohen's Kappa statistics (κ). Pearson's correlation coefficient was used for the relationship between continuous data. The diagnostic accuracy of SCT and QCT in the differentiation of clinically limited (mild, common) and extensive (severe, critical) disease was investigated using ROC analysis. Seventy-six patients with a diagnosis of COVID-19 were included. There was good agreement between the two observers in the SCT evaluation of pulmonary disease severity (κ = 0.796; 95% CI, 0.751-0.841). A significant correlation was found between QCT and SCT scores (p < 0.001, r = 0.661). Both QCT and SCT scores showed a significant correlation with clinical severity score (p < 0.001, r = 0.620 and p = 0.004, r = 0.529, respectively). The ROC analysis revealed the AUC of QCT and SCT for differentiation of limited and extensive disease as 0.873 (95% CI, 0.774-0.972) and 0.816 (95% CI, 0.673-0.959), respectively. The QCT assessment is an objective method in the evaluation of COVID-19 severity and is more successful than semiquantitative CT assessment to discriminate extensive from limited disease.

Dosimetric Effect of Biozorb Markers for Accelerated Partial Breast Irradiation in Proton Therapy.

PurposeTo investigate dosimetric implications of biodegradable Biozorb (BZ) markers for proton accelerated partial breast irradiation (APBI) plans.Materials and MethodsSix different BZs were placed within in-house breast phantoms to acquire computed tomography (CT) images. A contour correction method with proper mass density overriding for BZ titanium clip and surrounding tissue was applied to minimize inaccuracies found in the CT images in the RayStation planning system. Each breast phantom was irradiated by a monoenergetic proton beam (103.23 MeV and 8×8 cm2) using a pencil-beam scanning proton therapy system. For a range perturbation study, doses were measured at 5 depths below the breast phantoms by using an ionization chamber and compared to the RayStation calculations with 3 scenarios for the clip density: the density correction method (S1: 1.6 g/cm3), raw CT (S2), and titanium density (S3: 4.54 g/cm3). For the local dose perturbation study, the radiographic EDR2 film was placed at 0 and 2 cm below the phantoms and compared to the RayStation calculations. Clinical effects of the perturbations were retrospectively examined with 10 APBI plans for the 3 scenarios (approved by our institutional review board).ResultsIn the range perturbation study, the S1 simulation showed a good agreement with the chamber measurements, while excess pullbacks of 1∼2 mm were found in the S2 and S3 simulations. The film study showed local dose shadowing and perturbation by the clips that RayStation could not predict. In the plan study, no significant differences in the plan quality were found among the 3 scenarios. However, substantial range pullbacks were observed for S3.ConclusionThe density correction method could minimize the dose and range difference between measurement and RayStation prediction. It should be avoided to simply override the known physical density of the BZ clips for treatment planning owing to overestimation of the range pullback.

A new risk-scoring system to predict Xp11.2 translocation renal cell carcinoma in adults.

ObjectiveThe objective was to derive and validate a practical scoring system for preoperative diagnosis of Xp11.2 translocation renal cell carcinoma (RCC) in adults.MethodsEpidemiology, symptomatology, and imaging methods were correlated between patients with common RCC and those with Xp11.2 translocation RCC using a derivation study (N = 6352) and a validation study (N = 127). Univariate analysis of risk factors was performed to derive a scoring system to predict the occurrence of Xp11.2 translocation RCC in adults. The Hosmer–Lemeshow goodness-of-fit test and receiver operating characteristic (ROC) curve were used to validate the scoring system.ResultsBased on odd ratios, three low-risk factors (sex, gross haematuria, and intratumoural calcification) and three high-risk factors (age, unenhanced computed tomography density, and enhancement pattern) were given weighted scores of 1 and 2, respectively. Patients who scored 3 to 5 points underwent an additional magnetic resonance imaging examination. The final scoring system had a sensitivity of 81.0% and a specificity of 98.0%.ConclusionWe established a practical scoring system for the preoperative diagnosis of Xp11.2 translocation RCC in adults, which can be optimised through further clinical findings in the future.

Hyperdense Pancreatic Ductal Adenocarcinoma: Clinical Characteristics and Proteomic Landscape.

PurposeHypodensity of pancreatic ductal adenocarcinoma (PDAC) during contrast-enhanced computed tomography (CECT) examination is common, but a minority of PDAC patients exhibit hyperdense images. The present study examined the clinical characteristics and protein landscape of PDAC with hyperdensity.Materials and MethodsA total of 844 pathologically confirmed PDAC patients who underwent CECT before surgery were included. During the parenchymal phase of CECT, patients were assigned to the hyperdense or hypodense group based on CT values. Clinical and CT characteristics for predicting relapse-free survival (RFS) and overall survival (OS) were analyzed using the Kaplan–Meier method and Cox proportional hazards model. The expression of the tumor angiogenesis marker CD31 and stroma-related protein CTHRC1 were analyzed using immunohistochemistry (IHC) assay to evaluate differences between the two groups. Proteomics was performed to compare the possible mechanisms underlying the differential enhancement on CT scans.ResultsBased on CECT, 43 and 801 PDAC patients had hyperdense and hypodense lesions, respectively. All 43 patients presented a hyperdense lesion in the parenchymal phase. The mean CECT values of the hyperdense group were higher than the hypodense group (102.5 ± 17.4 and 53.7 ± 18.7, respectively, P < 0.001). The hyperdense group had a better prognosis than the hypodense group (median RFS, 19.97 vs. 12.34 months, P = 0.0176; median OS, 33.6 vs. 20.3 months, P = 0.047). Multivariate analysis showed that age, higher CA19-9 levels (> 300 U/ml), tumor stage, tumor differentiation, tumor CT density, and adjuvant chemotherapy were significant independent prognostic factors for OS. CD31 immunohistochemical staining showed that the hyperdense PDACs had a higher microvessel density than the hypodense group (P < 0.001). CTHRC1 expression was higher in the hypodense group (P = 0.019). Sixty-eight differentially expressed proteins were found using the tandem mass tag labeling-based quantification of the proteomes of PDAC tissue samples, and 7 proteins (POFUT1, PKP2, P0DOX4, ITPR1, HBG2, IGLC3, SAA2) were related to angiogenesis.ConclusionPatients who presented with a hyperdense mass on CECT had a higher microvessel density and better prognosis. Anti-angiogenic therapy may be suitable for these patients.

The feasibility and limitation of coronary computed tomographic angiography imaging to identify coronary lipid-rich atheroma in vivo: Findings from near-infrared spectroscopy analysis

BackgroundCoronary computed tomography angiography (CCTA) non-invasively visualizes lipid-rich plaque. However, this ability is not fully validated in vivo. The current study aimed to elucidate the association of CCTA features with near-infrared spectroscopy-derived lipidic plaque measure in patients with coronary artery disease. Methods95 coronary lesions (culprit/non-culprit = 51/44) in 35 CAD subjects were evaluated by CCTA and NIRS imaging. CT density, positive remodeling, spotty calcification, napkin-ring sign and NIRS-derived maximum 4-mm lipid-core burden index (maxLCBI4mm) were analyzed by two independent physicians. The association of CCTA-derived plaque features with maxLCBI4mm ≥ 400 was evaluated. ResultsThe median CT density and maxLCBI4mm were 57.7 Hounsfield units (HU) and 304, respectively. CT density (r = -0.75, p < 0.001) and remodeling index (RI) (r = 0.58, p < 0.001) were significantly associated with maxLCBI4mm, respectively. Although napkin-ring sign (p < 0.001) showed higher prevalence of maxLCBI4mm ≥ 400 than those without it, spotty calcification did not (p = 0.13). On multivariable analysis, CT density [odds ratio (OR) = 0.95, 95% confidence interval (CI) = 0.93–0.97; p < 0.001] and positive remodeling [OR = 7.71, 95%CI = 1.37–43.41, p = 0.02] independently predicted maxLCBI4mm ≥ 400. Receiver operating characteristic curve analysis demonstrated CT density <32.9 HU (AUC = 0.92, sensitivity = 85.7%, specificity = 91.7%) and RI ≥ 1.08 (AUC = 0.83, sensitivity = 74.3%, specificity = 85.0%) as optimal cut-off values of maxLCBI4mm ≥ 400. Of note, only 52.6% at lesions with one of these plaque features exhibited maxLCBI4mm ≥ 400, whereas the frequency of maxLCBI4mm ≥ 400 was highest at those with both features (88.5%, p < 0.001 for trend). ConclusionsCT density <32.9 HU and RI ≥ 1.08 were associated with lipid-rich plaque on NIRS imaging. Our findings underscore the synergistic value of CT density and positive remodeling to detect lipid-rich plaque by CCTA.

Value of 99mTc-MIBI SPECT/CT in distinguishing between parathyroid lesions and nodular goiter.

Hyperfunctioning parathyroid lesions require surgical resection. 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) plays an important role in the diagnosis of parathyroid lesions. Some nodular goiters have a higher uptake of 99mTc-MIBI, which is difficult to distinguish from hyperfunctioning parathyroid lesions. This study aims to explore the value of 99mTc-MIBI SPECT/CT in the differential diagnosis of parathyroid lesions and nodular goiter. This study was a retrospective analysis. A total of 68 patients who were diagnosed as parathyroid lesions by 99mTc-MIBI SPECT/CT were enrolled, with a total of 81 lesions. According to the results of pathological examination after surgical resection, the lesions were divided into a parathyroid lesion group (n=69) and a nodular goiter group (n=12). The target maximum radioactivity count (Tmax) of all lesions was measured. The mean radioactivity count of the aortic arch was used as the background mean radioactivity count (Bmean), and the ratio of the Tmax to Bmean was calculated. The difference in Tmax/Bmean between the 2 groups was compared. The minimum, mean, and maximum of CT density in the lesion were measured. The difference of CT density between the 2 groups was compared. The receiver operating characteristic (ROC) curve of patients with parathyroid lesions and patients with nodular goiter was drawn, and the diagnostic efficacy of each CT density value was evaluated. The 99mTc-MIBI radioactive uptake in parathyroid lesions and nodular goiter lesions was significantly concentrated. The CT density values of the 2 lesions were lower than normal thyroid tissue, and the boundary between the 2 lesions and the thyroid was clear or blurred. There was no significant difference in Tmax/Bmean between the 2 groups (P=0.221). The differences in the minimum, mean and maximum of CT density between the 2 groups were statistically significant (all P<0.05). The diagnostic efficiency of maximum of CT density was the best, area under the ROC curve was 0.894 (P<0.001), the cut-off was 91 HU, the sensitivity was 83.3%, and the specificity was 94.2%. The degree of 99mTc-MIBI radiation uptake in the focus has limited value in differentiating parathyroid lesions from nodular goiter, and the maximum density of CT possesses high diagnostic efficiency.

Computed Tomography Radiomics for Predicting Pathological Grade of Renal Cell Carcinoma.

BackgroundClear cell renal cell carcinoma (ccRCC) is the most common renal cancer and it has the worst prognosis among all renal cancers. However, traditional radiological characteristics on computed tomography (CT) scans of ccRCC have been insufficient to predict the pathological grade of ccRCC before surgery.MethodsPatients with ccRCC were retrospectively enrolled into this study and were separated into two groups according to the World Health Organization (WHO)/International Society of Urological Pathology (ISUP) grading system, i.e., low-grade (Grade I and II) group and high-grade (Grade III and IV) group. Traditional CT radiological characteristics such as tumor size, pre- and post-enhancing CT densities were assessed. In addition, radiomic texture analysis based on the CT imaging of the ccRCC were also performed. A CT-based machine learning method combining the traditional radiological characteristics and radiomic features was used in the predictive modeling for differentiating the low-grade from the high-grade ccRCC. Model performance was evaluated with the receiver operating characteristic curve (ROC) analysis.ResultsA total of 264 patients with pathologically confirmed ccRCC were included in this study. In this cohort, 206 patients had the low-grade tumors and 58 had the high-grade tumors. The model built with traditional radiological characteristics achieved an area under the curve (AUC) of 0.9175 (95% CI: 0.8765–0.9585) and 0.8088 (95% CI: 0.7064–0.9113) in differentiating the low-grade from the high-grade ccRCC for the training cohort and the validation cohort respectively. The model built with the radiomic textural features yielded an AUC value of 0.8170 (95% CI: 0.7353–0.8987) and 0.8017 (95% CI: 0.6878–0.9157) for the training cohort and the validation cohort, respectively. The combined model integrating both the traditional radiological characteristics and the radiomic textural features achieved the highest efficacy, with an AUC of 0.9235 (95% CI: 0.8646–0.9824) and an AUC of 0.9099 (95% CI: 0.8324–0.9873) for the training cohort and validation cohort, respectively.ConclusionWe developed a machine learning radiomic model achieving a satisfying performance in differentiating the low-grade from the high-grade ccRCC. Our study presented a potentially useful non-invasive imaging-focused method to predict the pathological grade of renal cancers prior to surgery.

Characterization of soy-lignin bonded Rhizophora spp. particleboard as substitute phantom material for radiation dosimetric studies – Investigation of CT number, mass attenuation coefficient and effective atomic number

Experimental particleboards are made from Rhizophora spp. wood trunk with three different percentages of lignin and soy flour (0%, 6% and 12%) as adhesives. The objective was to investigate the equivalence of Rhizophora spp. particleboard as phantom material with human soft tissue using Computed Tomography (CT) number. The linear and mass attenuation coefficient of Rhizophora spp. particleboard at low energy range was also explored using X-ray Fluorescence (XRF) configuration technique. Further characterization of the particleboard was performed to determine the effective atomic number, Zeff using Energy Dispersive X-Ray (EDX) method. Adhesive-bonded Rhizophora spp. particleboard showed close similarities with water, based on the average CT numbers, electron density calibration curve and the analysis of CT density profile, compared to the binderless particleboard. The effective atomic number obtained from the study indicated that the attenuation properties of all the particleboards at different percentages of adhesives were almost similar to water. The mass attenuation coefficient calculated from XRF configuration technique showed good agreement with water from XCOM database, suggesting its potential as phantom material for radiation study.

Pseudosubarachnoid hemorrhage: A systematic review of causes, diagnostic modalities, and outcomes in patients who present with pseudosubarachnoid hemorrhage.

Background: Patients with computed tomography (CT) findings consistent with subarachnoid hemorrhage without evidence of hemorrhage following autopsy or cerebrospinal fluid testing are termed to have pseudosubarachnoid hemorrhage (pSAH).Methods: A systematic review of literature was conducted based on the preferred reporting items for systematic reviews and meta-analysis statement. Studies were evaluated for associated cause of pSAH, imaging modality used in assessment, method of confirmatory testing, and clinical outcome.Results: Fifty studies were included in qualitative analysis including 197 cases of pSAH. Systematic review revealed 23 studies including 110 patients with pSAH attributed to hypoxic-ischemic brain injury following cardiac arrest. Three studies were included in meta-analysis that quantitatively analyzed differences in CT densities in patients with pSAH and true subarachnoid hemorrhage (true SAH). A random effects model meta-analysis showed a statistically significant decrease in densities in the Sylvian fissure in patients with pSAH compared to true SAH and a statistically significant decrease in densities in adjacent parenchyma in patients with pSAH compared to true SAH. Systematic review further revealed 32 patients with pSAH associated with spontaneous intracranial hypotension, 11 patients with pSAH related to infectious etiologies, 15 patients with pSAH associated with subdural hemorrhage, 20 cases of pSAH related to hyperhemoglobinemia, 2 cases related to valproate toxicity, and individual cases related to hyponatremia, diabetic ketoacidosis, sudden infant death syndrome, cerebellar infarction, and dialysis disequilibrium syndrome.Conclusion: This study is the first systematic review of causes, diagnostic modalities, and outcomes in patients who present with pSAH. A diagnosis of pSAH may be considered following assessment of CT densities following cardiac arrest.

Facies characterisation of sediments from the East Frisian Wadden Sea (Germany): new insights from down-core scanning techniques

AbstractSediment facies provide fundamental information to interpret palaeoenvironments, climatic variation, archaeological aspects and natural resource potentials since they are summary products of depositional processes, environmental conditions and biological activities for a given time and location. The conventional method of facies discrimination relies on macroscopic and/or microscopic determination of sediment structures combined with basic physical, chemical and biological information. It is a qualitative measure, depending on observer-dependent sedimentological descriptions, which cannot be reanalysed readily by further studies. Quantitative laboratory measurements can overcome this disadvantage, but are in need of large sample numbers and/or high temporal resolution, and are time-, labour- and cost-intensive. In order to facilitate an observer-independent and efficient method of facies classification, our study evaluates the potential of combining four non-destructive down-core scanning techniques: magnetic susceptibility (MS), X-ray computed tomography (CT), X-ray fluorescence (XRF) and digital photography. These techniques were applied on selected sections of sediment cores recovered around the island of Norderney (East Frisian Wadden Sea, Germany). We process and integrate the acquired scanning measurements of XRF elemental intensities, represented by principal components, MS, CT density and lightness of eight sediment facies previously recognised by conventional facies analysis: moraine, eolian/fluvial, soil, peat, lagoonal, sand flat, channel fill and beach-foreshore. A novel type of density plot is introduced to visualise the digitised sediment information that allows an observer-independent differentiation of these facies types. Thus, the presented methodology provides the first step towards automated supervised facies classification with the potential to reproduce human assessments in a fully reproducible and quantitative manner.

Diagnosing nonalcoholic fatty liver disease in patients with intrahepatic cholangiocarcinoma: pitfalls of imaging and pathologic criteria

Presenter: Thomas Sutton MD | Oregon Health and Science University Background: Intrahepatic cholangiocarcinoma (ICC) is increasing in incidence and is potentially associated with non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH). The presence of both NAFLD and NASH has been shown to affect overall survival in patients with resected ICC. Steatosis, the primary criterion for NAFLD/NASH, may be under-reported on pathology and imaging, potentially impacting epidemiologic conclusions used to guide high-risk screening and treatment recommendations for ICC. We sought to evaluate the performance of standard-of-care (SOC) pathology, computed tomography (CT), and magnetic resonance imaging (MRI) for identifying steatosis. Methods: We identified n=52 patients with ICC treated with curative-intent resection from 2004-17. Hepatobiliary pathologists and radiologists specifically re-reviewed areas of non-malignant liver on tissue sections and pre-operative imaging, respectively, for evidence of steatosis. The pathologic criterion for steatosis was >5% of surface area involved by steatosis as evaluated by low to medium power examination. For MRI, chemical shift artifact seen on standard in and out-of-phase T1-weighted imaging was utilized to identify steatosis. For CT, density measurements were utilized, either absolute measurements on non-contrast CT or relative densities between liver and spleen when only post-contrast portal venous phase images were available. Using the dedicated pathology re-review as the reference, the accuracy of SOC pathology, contrasted CT, and MRI for diagnosing steatosis was evaluated by receiver operating characteristics (ROC) analysis. Results: The median patient age was 64-years with an equal gender distribution. The median body mass index was 30.3 kg/m2, and 11 (21%) patients had diabetes mellitus. Dedicated pathology review identified steatosis in 20 patients (38%) and was discordant from original reports in 8 cases (15%), with 4 instances each of over-diagnosis and under-diagnosis. On ROC analysis, the original pathology report correctly identified steatosis with an area under the curve (AUC) of 0.87 (P < 0.001 compared to chance), while MRI had an AUC of 0.83 (P < 0.001). Dedicated CT review was less accurate for steatosis (AUC 0.65, P=0.01), and SOC CT was not significantly better than chance (AUC 0.58, P=0.5)(Figure). Conclusion: SOC imaging, SOC pathologic examination, and dedicated review of imaging are less accurate in the diagnosis of steatosis compared to dedicated pathologic review of non-malignant liver tissue. The authors suspect this could be due to the lack of emphasis on documenting steatosis by pathologists and radiologists in cases of malignancy, where documenting cancer-associated features is understandably the primary focus. Epidemiologic studies relying on SOC imaging reports, and to a lesser extent those relying on SOC pathology or dedicated imaging review, are limited in their validity when associating NAFLD with primary liver cancers such as ICC and should be interpreted with caution.

Pseudo-hyperdense MCA sign: The value of comparing CT densities of vessels on both sides

Hyperdense middle cerebral artery (MCA) sign is a well-recognised sign of stroke radiology. However, less often reported is the pseudo 'hyperdense MCA sign' that looks ominous and may confound the clinician into thinking that he is dealing with a case of ischaemic stroke. We report a 56-year-old male who nearly underwent thrombolysis due to this sign seen on initial computed tomography imaging and highlight the way to avoid this pitfall.

PSEUDOMYXOMA ON APPENDICULAR MUCOCELE

Mucocele of the appendix is a descriptive term for mucinous distension of the appendiceal lumen (vermiform appendix) regardless of the underlying pathology. It refers to the progressive retrograde dilatation of the vermiform appendix with concomitant intraluminal accumulation of the mucoid substance. It is an uncommon pathology that occurs in both sexes. it especially poses the problem of differential diagnosis in particular in women because of the location of clinical symptoms in the right iliac fossa. The incidence is estimated between 0.2 % and 0.4 % of the appendectomied specimens.The estimated incidence is approximately 1/1 000 000/year. The disease onset is usually after the age of 40 years and more frequently affects females.The means of medical imaging are mainly ultrasound and scanner. On CT typical mucocele appears as a cecal-based, rounded and well-defined mass, thin-walled, with fine parietal calcifications CT density is variable, from fluid to tissue. A stercolith is sometimes visible at the base of the appendix. The wall of the mucocele may be thickened, irregular, taking the contrast there may be peri-appendicular inflammation, which may be inflammatory or tumor, without specificity.The treatment of unbroken appendicular mucocele is surgical, preferably by laparotomy than laparoscopy. The appendectomy is performed, without breaking the appendix, with complete resection of the meso-appendix, and sampling for cytology of the peritoneal fluid.

Diaphragm Morphology Assessed by Computed Tomography in Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) is associated with abnormal skeletal muscle morphology and function. Objectives: To test the hypothesis that in vivo diaphragm muscle morphology assessed by computed tomography (CT) imaging would be associated with COPD severity, exacerbations, health status, and exercise capacity. Methods: The COPD Morphometry Study is a cross-sectional study that enrolled a clinical sample of smokers with COPD. Spirometry was performed and COPD severity was defined according to guidelines. Three-dimensional left hemidiaphragm morphology was segmented from contiguous axial CT images acquired at maximal inspiration, yielding quantitative measures of diaphragm CT density in Hounsfield units, dome height, and muscle volume. Exacerbations prompting pharmacotherapy or hospitalization in the preceding 12 months and St. George's Respiratory Questionnaire for COPD were assessed. Incremental symptom-limited cycle ergometry quantified peak oxygen uptake ([Formula: see text]o2Peak). Associations were adjusted for age, sex, body height, body mass index, and smoking status. Results: Among 65 smokers with COPD (75% male; [mean ± standard deviation (SD)] 56 ± 26 pack-years; forced expiratory volume in 1 second [FEV1] percentage predicted 55 ± 23%), mean diaphragm CT density was 3.1 ± 10 Hounsfield units, dome height was 5.2 ± 1.3 cm, and muscle volume was 57 ± 24 cm3. A 1-SD decrement in the diaphragm CT density was associated with 8.3% lower FEV1, 3.27-fold higher odds of exacerbation history, 9.7-point higher score on the St. George's Respiratory Questionnaire for COPD, and 2.5 ml/kg/min lower [Formula: see text]o2Peak. A 1-SD decrement in dome height was associated with 11% lower FEV1 and 1.3 ml/kg/min lower [Formula: see text]o2Peak. There were no associations with diaphragm volume observed. Conclusions: CT-assessed diaphragm morphology was associated with COPD severity, exacerbations, impaired health status, and exercise intolerance. The mechanisms and functional impact of lower diaphragm CT density merit investigation.

Increased 18F-FDG accumulation in less-affected lung area in patients with non-small cell lung cancer and postoperative acute exacerbation of interstitial lung disease

PurposeTo investigate whether or not 18F-FDG accumulation in normal or less-affected lung fields increased in non-small cell lung cancer (NSCLC) patients with postoperative acute exacerbation (PAE) of interstitial lung disease (ILD) Material and methodsThirty-six NSCLC patients with ILD and 50 patients without ILD (non-ILD patients) underwent pre-operative 18F-FDG-PET/CT at 2 institutions. Volume-of-interest (VOI) was placed to measure the mean standardized uptake value (SUVmean) in normal or less-affected lung fields at pre-defined 12 areas on ventral and dorsal locations of both lungs. SUVtissue fraction (TF) was defined as corrected SUVmean by using TF and mean computed tomography density on PET/CT. Harmonized SUVmean (hSUVmean) and SUVTF (hSUVTF) were calculated based on results of phantom study, which was performed to optimize the measured SUV difference among 2 institutions. Both the h-SUVmean and the h-SUVTF were compared between 8 patients with PAE of ILD (PAE group) or remaining 28 patients without PAE of ILD (non-PAE group) and non-ILD patients in each of the 12 areas. ResultsThe hSUVmean in PAE group was higher in 9 out of 12 locations as compared with non-ILD patients, whereas the hSUVmean was mostly similar between non-PAE group and non-ILD patients. In contrast, the hSUVTF in non-PAE group was similar to that in PAE group, and higher than in non-ILD patients in most locations. Conclusion18F-FDG-PET/CT demonstrated increased SUVmean along with elevated SUVTF in normal or less-affected lung fields for NSCLC patients with PAE of ILD, which may reflect regional invisible fibrosis and inflammatory change.

Semi-quantitative CT imaging in improving visualization of faint ground glass opacities seen in early/mild coronavirus (covid-19) cases

BackgroundChest CT is an essential and simple diagnostic method for early detection of pulmonary changes in COVID-19 patients. Semi-quantitative technique depending on both visual and color coded images helps to improve the early detection of COVID-19 chest affection and thus help to control spread of infection.ResultsFrom first of May to July 15, 2020, 30 patients in Cairo, Egypt who have positive RT-PCR tests and positive pulmonary manifestation were included in our study, 26 patients (86.6%) with faint ground glass opacities were detected by both visual and color coded images, while in 4 patients (13.3%) were only visualized by color coded images and confirmed by CT density assessment.ConclusionThe combined use of visual and color coded images enhance and improve the early detection of faint ground glass opacities seen in early COVID-19 affection.

HIGH-RESOLUTION CT FEATURES OF THE COVID-19 INFECTION, INITIALAND FOLLOW-UP CHANGES AMONG DIFFERENT CLINICAL TYPES

Background: To discuss the high resolution computed tomography (HRCT) manifestations of corona virus disease 2019 (COVID-19) patients among different clinical types on initial and follow-up CT. Methods: Seventy COVID-19 patients admitted to the Affiliated Hospital of SP Medical Collage Bikaner were enrolled. All patients underwent initial and follow-up chest HRCT. The main CT features and semi-quantitative score which represent disease severity among different clinical types were evaluated. Result: On initial CT, the main abnormalities observed in common and severe cases respectively were pure ground glass opacities (GGOs) and patchy consolidation surrounded by GGOs. Critical cases had multiple consolidation surrounded by wide range of GGOs distributed in the whole lung fields. The CT severity score and density score in mild (up to 8 and 5), moderate (&gt;8 to 15 and 9) and severe (&gt;15 and 12) cases were increased by gradient. On follow-up CT, mild and moderate types manifested as decreasing density of lesion, absorbed consolidation and GGOs. Severe cases showed progression of the disease. The extent and progression scores in mild and moderate patients were significantly decreased, while the range score of patients with severe disease reached the highest points, accompanied with an increase in the density score. Conclusion: CT scanning can accurately assess the severity of COVID-19, and help to monitor disease transformation during follow-up among different clinical conditions.

Flow-controlled ventilation during EVLP improves oxygenation and preserves alveolar recruitment

BackgroundEx vivo lung perfusion (EVLP) is a widespread accepted platform for preservation and evaluation of donor lungs prior to lung transplantation (LTx). Standard lungs are ventilated using volume-controlled ventilation (VCV). We investigated the effects of flow-controlled ventilation (FCV) in a large animal EVLP model.Fourteen porcine lungs were mounted on EVLP after a warm ischemic interval of 2 h and randomized in two groups (n = 7/group). In VCV, 7 grafts were conventionally ventilated and in FCV, 7 grafts were ventilated by flow-controlled ventilation. EVLP physiologic parameters (compliance, pulmonary vascular resistance and oxygenation) were recorded hourly. After 6 h of EVLP, broncho-alveolar lavage (BAL) was performed and biopsies for wet-to-dry weight (W/D) ratio and histology were taken. The left lung was inflated, frozen in liquid nitrogen vapors and scanned with computed tomography (CT) to assess regional distribution of Hounsfield units (HU).ResultsAll lungs endured 6 h of EVLP. Oxygenation was better in FCV compared to VCV (p = 0.01) and the decrease in lung compliance was less in FCV (p = 0.03). W/D ratio, pathology and BAL samples did not differ between both groups (p = 0.16, p = 0.55 and p = 0.62). Overall, CT densities tended to be less pronounced in FCV (p = 0.05). Distribution of CT densities revealed a higher proportion of well-aerated lung parts in FCV compared to VCV (p = 0.01).ConclusionsFCV in pulmonary grafts mounted on EVLP is feasible and leads to improved oxygenation and alveolar recruitment. This ventilation strategy might prolong EVLP over time, with less risk for volutrauma and atelectrauma.

Basic Consideration for Facial Aging: Analyses of the Superficial Musculoaponeurotic System Based on Anatomy.

The superficial musculoaponeurotic system (SMAS) is an important structure to understand for face-lift surgeries. However, the detailed distribution and imaging findings of the SMAS have not been established yet. The aim of this study was to establish the accurate distribution and computed tomography (CT) imaging findings of the SMAS based on cadaveric studies. This study was designed in a 3-step procedure. First, 7 cadaver faces were utilized to understand the distribution and histology of the SMAS. Second, the SMAS findings from the cadaveric studies were compared with the CT images. Third, CT images were enrolled for the SMAS interpretation. In 7 cadaveric studies, the SMAS was observed as a subcutaneous fibro-membranous structure extending from the galea aponeurotica to the platysma muscle and laterally connected to the parotid fascia. On the medial side, it also connects with major and minor zygomatic muscles. The SMAS consisted of muscular fibers, collagen fibers, and elastic fibers histologically. Eighteen CT images (all females; age range, 21-82 years) showed the thin linear structures corresponding to the fibro-membranous structures in the cadaveric studies. CT density of the SMAS was similar with that of the muscle, and the SMAS was recognizable in all 18 subjects. The SMAS is a definite anatomical structure that can be demonstrated as a thin membranous structure on CT. This clinical application could be applicable to the development the cosmetic surgical procedures.

Clinical Outcomes of Subcutaneous and Visceral Adipose Tissue Characteristics Assessed in Patients Underwent Transcatheter Aortic Valve Replacement

BackgroundAdipose tissue (AT) characteristics are considered to be a marker for predicting clinical outcomes. This study aimed to investigate the prognostic value of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) computed tomography (CT) assessment in patients who underwent transcatheter aortic valve replacement (TAVR). MethodsWe used the Japanese multicentre registry data of 1372 patients (age: 84.5 ± 5.0 years, women: 70.6%) who underwent TAVR. The SAT and VAT were assessed according to the preprocedural CT area and density. Baseline characteristics and clinical outcomes were compared based on the differences in AT characteristics. The independent associations with all-cause mortality after TAVR were evaluated according to the CT area and density of AT. ResultsLow-volume area of SAT and VAT was associated with worse clinical outcomes compared with high-volume area of SAT and VAT in patients who underwent TAVR (log-rank test P = 0.016 and P = 0.014). High CT density of SAT and VAT was associated with increasing mortality in comparison with low CT density of SAT and VAT (log-rank test P < 0.001 and P = 0.007). The Cox regression multivariate analysis demonstrated the independent association of increased all-cause mortality in the high SAT and VAT density (hazard ratio [HR]: 1.41, 95% confidence interval [CI]: 1.06-1.88, P = 0.019, and HR: 1.34, 95% CI: 1.03-1.76, P = 0.031, respectively), but not in the low SAT and VAT area (HR: 0.85, 95% CI: 0.74-1.29, P = 0.85, and HR: 0.78, 95% CI: 0.60-1.03, P = 0.085, respectively). ConclusionsCT-derived AT characteristics, particularly the qualitative assessments, were useful for predicting the prognosis in patients after TAVR.