CT Attenuation Values Research Articles

Mediastinal aberrant goiter characterized by high radiodensity on non-enhanced computed tomography: a case report

BackgroundA mediastinal aberrant goiter is extremely rare, characterized by independence from the thyroid gland. This tumor most commonly develops in the anterior mediastinum and should be differentiated from a thymoma. Moreover, as mediastinal aberrant goiters frequently have a blood supply arising from the thoracic great vessels, preoperative diagnosis and evaluation of the feeding vessel are vital for safe surgery. Herein, we report a rare case of mediastinal aberrant goiter characterized by high radiodensity on non-enhanced computed tomography (CT).Case presentationA 77-year-old woman underwent non-enhanced CT, which showed a 2.2-cm, well-circumscribed, homogeneous anterior mediastinal nodule with high radiodensity. The CT attenuation value of the nodule was as high as 91.9 Hounsfield units. A thymoma or mediastinal goiter was suspected owing to the tumor location and the lack of a cystic component. We performed anterior mediastinal tumor resection using video-assisted thoracoscopic surgery. Pathologically, variably sized follicles, indicative of thyroid tissue, were observed with hemorrhage and hemosiderin deposition. Moreover, papillary projections of small follicles (Sanderson’s polsters) were scattered without atypia of the follicular epithelium, indicative of an adenomatous goiter. The diagnosis of a mediastinal aberrant goiter was supported by the absence of an anatomical connection with the thyroid gland. The postoperative course was uneventful, and the patient was discharged on postoperative day 5.ConclusionThe thyroid gland has a high radiodensity on non-enhanced CT, which correlates with iodine concentration. This radiological feature may be useful for the preoperative differentiation of mediastinal aberrant goiters containing thyroid tissue.

Imaging features of intraductal tubulopapillary neoplasm of the pancreas and its differentiation from conventional pancreatic ductal adenocarcinoma

Intraductal tubulopapillary neoplasms (ITPN) are rare pancreatic tumors (< 1% of exocrine neoplasms) and are considered to have better prognosis than classical pancreatic ductal adenocarcinoma (PDAC). The present study aimed to evaluate imaging features of ITPN in computed tomography (CT) and magnetic resonance (MR) imaging. We performed monocentric retrospective analysis of 14 patients with histopathologically verified ITPN, operated in 2003–2018. Images were available for 12 patients and were analysed independently by two radiologists, blinded to reports. Imaging features were compared to a matched control group consisting of 43 patients with PDAC, matched for sex and age. Histopathologic analysis showed invasive carcinoma component in all ITPN patients. CT-attenuation values of ITPN were higher in arterial and venous phases (62.3 ± 14.6 HU and 68 ± 15.6 HU) than in unenhanced phase (39.2 ± 7.9 HU), compatible with solid lesion enhancement. Compared to PDAC, ITPN lesions had significantly higher HU-values in both arterial and venous phases (arterial and venous phases, p < 0.001). ITPN were significantly larger than PDAC (4.1 ± 2.0 cm versus 2.6 ± 0.84 cm, p = 0.021). ITPN lesions were more often well-circumscribed (p < 0.002). Employing a multiple logistic regression analysis with forward stepwise method, higher HU density in the arterial phase (p = 0.012) and well-circumscribed lesion margins (p = 0.047) were found to be significant predictors of ITPN versus PDAC. Our study identified key imaging features for differentiation of ITPN and PDAC. Isodensity or moderate hypodensity and well-circumscribed margins favor the diagnosis of ITPN over PDAC. Being familiar with CT-features of these rare pancreatic tumors is essential for radiologists to accelerate the diagnosis and narrow the differentials.

Pathological components and CT imaging analysis of the area adjacent pleura within the pure ground-glass nodules with pleural deformation in invasive lung adenocarcinoma

BackgroundPleural deformation is associated with the invasiveness of lung adenocarcinoma(LAC). Our study focused on the pathological components of the area adjacent pleura in pulmonary pure ground-glass nodules(pGGNs) with pleural deformations(P-pGGNs) confirmed to be invasive LAC without visceral pleural invasion (VPI) pathologically.MethodsComputed tomography(CT) imaging features of nodules and pathological components of the area adjacent pleura were analyzed and recorded. Statistical analysis was performed for subgroups of P-pGGNs.ResultsThe 81 enrolled patients with 81 P-pGGNs were finally involved in the analysis. None of solid/micropapillary group and none of VPI was observed, 54 alveoli/lepidics and 27 acinar/papillarys were observed. In P-pGGN with acinar/papillary components of the area adjacent pleura, invasive adenocarcinoma (IAC) was more common compared to minimally invasive adenocarcinoma (MIA, 74.07% vs. 25.93%; p < 0.001). The distance in alveoli/lepidic group was significantly larger (1.50 mm vs. 0.00 mm; p < 0.001) and the depth was significantly smaller (2.00 mm vs. 6.00 mm; p < 0.001) than that in acinar/papillary group. The CT attenuation value, maximum diameter and maximum vertical diameter was valuable to distinguish acinar/papillary group form alveoli/lepidic group(p < 0.05). The type d pleural deformation was the common pleural deformation in IAC(p = 0.028).ConclusionsThe pathological components of the area adjacent pleura in P-pGGN without VPI confirmed to be invasive LAC could included alveoli/lepidics and acinar/papillarys. Some CT indicators that can identify the pathological invasive components of the area adjacent pleura in P-pGGNs.

Effect of intravenous iodinated contrast administration on diagnostic ability for osteoporosis using CT attenuation measurement in patients with liver cirrhosis.

To evaluate the influence of intravenous contrast agent on the diagnostic ability for osteoporosis using CT attenuation measurement in patients with liver cirrhosis. This retrospective study was approved by our institutional review board and informed consent was waived. 208 patients with liver cirrhosis (mean age, 61.25 years ± 9.43 [standard deviation]; range, 30-82 years) who underwent both unenhanced and two contrast-enhanced (arterial and venous phase) abdominal dual-energy CT examinations from January 1 to September 1, 2020, were recruited. CT attenuation values were measured in the medullary compartment of vertebral body (L1-L3) and bone mass was determined by the hydroxyapatite concentration obtained in dual-energy spectral CT and used as the reference standard. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic ability of using CT attenuation number in unenhanced, arterial, and venous phases. Area under ROC curve using unenhanced CT attenuation was different from using arterial CT attenuation (p= 0.038) and venous CT attenuation (p = 0.048) to diagnosing osteoporosis. However, there was no significant difference between unenhanced CT attenuation and arterial CT attenuation (p = 0.773) and between unenhanced CT attenuation and venous CT attenuation (p = 0.746) to distinguish low bone mass (osteoporosis or osteopenia). The diagnostic ability for osteoporosis using CT attenuation measurement in contrast-enhanced scans is decreased due to intravenous contrast contamination, however, which had no influence on the diagnostic ability of CT attenuation for low bone mass (osteoporosis or osteopenia). The diagnostic ability of using enhanced CT attenuation values for osteoporosis decreased compared to unenhanced CT attenuation values.

The ratio of CT attenuation values of the ureter above/below ureteral stones is a useful preoperative factor for predicting impacted ureteral stones.

Impacted stones typically make it difficult to perform ureteroscopic lithotripsy (URSL), so it is useful to preoperatively predict such impaction. We focused on CT attenuation values of the ureter above and below the stone ('HU above' and 'HU below') and calculated their ratio (HAB ratio; HU above/HU below ratio). The aim was to investigate whether HAB ratio could predict impacted stones preoperatively. Between 2011 and 2019, 171 patients from our hospital that had URSL for ureteral stones with pretreatment non-contrast computed tomography (NCCT) were retrospectively identified. Ureteral wall thickness (UWT), ureteral wall volume (UWV) and HAB ratio ('HU above' divided by 'HU below') were recorded. Impacted stones were defined as fixed stones that did not move by means of ureteroscopic manipulation or water pressure. Of the 171 procedures, 46 (27%) involved patients with impacted stones. Comparing patient characteristics and stone parameters according to impaction status, factors with significant difference included grade of hydronephrosis, UWT, and HAB ratio (all P < 0.01). Multivariate analysis indicated that significant independent predictors of impacted stones were thicker UWT and lower HAB ratio (all P < 0.01). HAB ratio was a significant preoperative predictor of stone impaction in patients undergoing URSL for ureteral stones. HAB ratio may be informative for selecting the treatment and preoperative preparations.

Evaluation of age-related thymic changes using computed tomography images: A retrospective observational study.

We aimed to investigate if Computed tomography (CT) attenuation values can help improve the identification of age-related changes in the thymus.We assessed CT images of 405 patients aged 0 to 80 years. We measured the area of the anterior mediastinum at the level of the carina and its average CT attenuation value. We evaluated the thymic area, the ratio of the thymus area to the total thoracic area, and the CT attenuation value. Additionally, we evaluated changes in the thymus area in the 0 to 13-year age group.The area of the thymus decreased from birth to the middle 20s. After the middle 20s, the area tended to increase and plateau till after 50 years of age. The ratio of the thymic area to the thoracic area decreased from age 0 to 20 years, but remained stable after 20 years of age. The CT attenuation values were stable from birth to puberty, decreased after puberty, and were stable again in the late 50s and beyond. The thymus of children showed mass formation, but the shape changed with age. No significant differences in the CT attenuation value were found across underlying conditions for the 0 to 13-year age group.The decrease in the CT attenuation values, observed with advancing age, reflects adipose degeneration of the thymus, indicating that by the late 50s, thymic tissue is replaced completely by adipose tissue. Our data suggest that adipose degeneration of the thymus begins after puberty and advances with age.

Association between osteoporosis and vascular calcification in patients with severe aortic stenosis

Background and Aims : Frequency of atherosclerosis and osteoporosis increases by ageing and vascular calcification is associated with osteoporosis. Despite diagnosis of osteoporosis is confirmed by bone mineral density (BMD); measure of L1 vertebrae computed tomography (CT) attenuation value is correlated with BMD measurements. In this study, we aimed to evaluate relationship between vascular calcification and CT diagnosed osteoporosis.Methods: Patients who underwent CT for TAVR planning between 2013 and 2020 were screened and L1 vertebrae CT attenuation values (HU) were measured for the assessment for osteoporosis. Cut-off value for osteoporosis diagnosis was determined as 135 HU. Parameters regarding vascular calcification were also measured from CT images.Conclusions: Osteoporosis is associated with vascular calcification with several underlying mechanisms. This study shows that presence of renal artery stenosis and both presence and severity of MAC are more frequent in patients with osteoporosis. Background and Aims : Frequency of atherosclerosis and osteoporosis increases by ageing and vascular calcification is associated with osteoporosis. Despite diagnosis of osteoporosis is confirmed by bone mineral density (BMD); measure of L1 vertebrae computed tomography (CT) attenuation value is correlated with BMD measurements. In this study, we aimed to evaluate relationship between vascular calcification and CT diagnosed osteoporosis. Methods: Patients who underwent CT for TAVR planning between 2013 and 2020 were screened and L1 vertebrae CT attenuation values (HU) were measured for the assessment for osteoporosis. Cut-off value for osteoporosis diagnosis was determined as 135 HU. Parameters regarding vascular calcification were also measured from CT images. Conclusions: Osteoporosis is associated with vascular calcification with several underlying mechanisms. This study shows that presence of renal artery stenosis and both presence and severity of MAC are more frequent in patients with osteoporosis.

Prevalence of Hepatic Steatosis in Adults Presenting to the Emergency Department Identified by Unenhanced Chest CT

This study aimed to investigate the prevalence of hepatic steatosis in racially diverse adults presenting to the emergency department at a tertiary healthcare system in the United States using attenuation values on unenhanced computed tomography (CT) as the reference standard. The utility of known risk factors for predicting the presence of hepatic steatosis was assessed. Additionally, reporting of hepatic steatosis in original radiology reports was evaluated. For 381 consecutive adults (193 women and 188 men; mean age 55.2 ± 17.2 years), hepatic (left medial, left lateral, right anterior, and right posterior) and splenic (upper, middle, and lower) CT attenuation values (Hounsfield units) were obtained by drawing a 1 cm2 region of interest on unenhanced chest CT obtained in the emergency department for any indication. Multiple attenuation criteria for steatosis, including liver thresholds and liver and spleen attenuation comparison, were applied. Relevant clinical risk factors were recorded and compared against a liver/ spleen attenuation ratio of ≤ 1.1 to include all individuals with steatosis in the analysis. Mean liver attenuation was 59.5 ± 10.4 HU. The prevalence of hepatic steatosis ranged from 5-35.4% depending on the CT attenuation criterion used (5%, liver attenuation ≤ 40 HU; 6.3%, liver attenuation ≤ (spleen attenuation - 10 HU); 16.8%, liver attenuation ≤ spleen attenuation; 34.1%, liver attenuation ≤ (spleen attenuation+5 HU); 35.4%, liver attenuation/ spleen attenuation ≤ 1.1). The prevalence of hepatic steatosis was higher in males compared to females (P=0.01, 42% vs 29%) and age 40-65 years when compared to the rest (P=0.03, 43.5% vs 32.2%), but similar across different racial (P=0.55), ethnic (P=0.78) groups. Overweight status (body mass index >25) and hypertension were sensitive indicator for steatosis (sensitivity=60.7% and 60.5%) but were highly nonspecific (specificity=41.9% and 49.2%). Other clinical risk factors, such as diabetes, dyslipidemia, alcohol overuse, and hepatitis, were more specific (specificity=62.2%-93.9%) but highly insensitive (sensitivity=7.5%-40.3%). 63% (12/19) radiology reports mentioned the presence of moderate-to-severe hepatic steatosis but only 11.1% (15/135) of them mentioned the presence of mild hepatic steatosis. Unenhanced chest CT can be used to assess hepatic steatosis for individuals presenting to the emergency department and provide a non-invasive means for opportunistic screening.

Computed tomographic evaluation of three types of screw trajectories for posterior cervical spine fixation: Cervical pedicle screw, lateral mass screw, and paravertebral foramen screw.

Computed tomography (CT) attenuation values of cervical spine were evaluated in vivo using a clinically relevant group. To compare CT attenuation values between cervical pedicle screw (CPS), lateral mass screw (LMS), and paravertebral foramen screw (PVFS) trajectories. CPS and LMS are commonly used for posterior fixation of the cervical spine. The PVFS method has been reported as a new method. CT attenuation values along the screw trajectory are reportedly associated with screw stability. We identified 45 patients who had undergone whole-body CT for trauma with no injury to the cervical spine. Regions of interest (ROIs) were designated along the trajectories that would be used for CPS, LMS, and PVFS through vertebral pedicles and lateral masses of the C3-C6 vertebrae. CT attenuation values of each ROI were measured and compared between each screw trajectories at each cervical vertebral level. Participants were divided into Group I (age, 20-39 years; n = 12), Group II (age, 40-59 years; n = 17), and Group III (age, 60-79 years; n = 16). CT attenuation values of ROIs were compared between each age group. PVFS trajectories showed higher CT attenuation values than LMS trajectories at every vertebral level and also higher values than CPS trajectories at C5 and C6 levels. CT attenuation values at C3 were lower than those at C4 in the LMS trajectory and lower than those at C5 and C6 in the PVFS trajectory. CT attenuation values were lower in the elder group (>60 years old) than in the other 2 groups for all screw trajectories. CT attenuation values suggested that the PVFS technique may be useful for posterior fixation of the cervical spine in elder patients who require more secure fixation.

Influence of a Deep Learning Noise Reduction on the CT Values, Image Noise and Characterization of Kidney and Ureter Stones.

Deep-learning (DL) noise reduction techniques in computed tomography (CT) are expected to reduce the image noise while maintaining the clinically relevant information in reduced dose acquisitions. This study aimed to assess the size, attenuation, and objective image quality of reno-ureteric stones denoised using DL-software in comparison to traditionally reconstructed low-dose abdominal CT-images and evaluated its clinical impact. In this institutional review-board-approved retrospective study, 45 patients with renal and/or ureteral stones were included. All patients had undergone abdominal CT between August 2019 and October 2019. CT-images were reconstructed using the following three methods: filtered back-projection, iterative reconstruction, and PixelShine (DL-software) with both sharp and soft kernels. Stone size, CT attenuation, and objective image quality (signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)) were evaluated and compared using Bonferroni-corrected Friedman tests. Objective image quality was measured in six regions-of-interest. Stone size ranged between 4.4 × 3.1–4.4 × 3.2 mm (sharp kernel) and 5.1 × 3.8–5.6 × 4.2 mm (soft kernel). Mean attenuation ranged between 704–717 Hounsfield Units (HU) (soft kernel) and 915–1047 HU (sharp kernel). Differences in measured stone sizes were ≤1.3 mm. DL-processed images resulted in significantly higher CNR and SNR values (p < 0.001) by decreasing image noise significantly (p < 0.001). DL-software significantly improved objective image quality while maintaining both correct stone size and CT-attenuation values. Therefore, the clinical impact of stone assessment in denoised image data sets remains unchanged. Through the relevant noise suppression, the software additionally offers the potential to further reduce radiation exposure.

The Change in the Fibrosis-4 Index for the Assessment of Liver Fibrosis After Pancreaticoduodenectomy.

Nonalcoholic fatty liver is a complication of pancreaticoduodenectomy (PD); however, liver fibrosis after PD is not well documented. Therefore, we estimated the hepatic fibrotic index of nonalcoholic fatty liver after PD. We retrospectively examined the electronic medical records of patients who had underwent PD and had computed tomography (CT) records preoperatively and 6 months postoperatively between 2011 and 2019 at the Shiga University of Medical Science Hospital. Overall, 115 patients were enrolled. After 6 months from PD, body mass index significantly decreased from 21.90 to 19.57 kg/m2 (-10.6%). The Fibrosis-4 (FIB-4) index significantly increased from 1.756 to 2.384 (P &lt; 0.001). The FIB-4 grade significantly worsened. Contrarily, neither the albumin-bilirubin (ALBI) score nor the ALBI grade demonstrated significant differences. The CT attenuation value significantly decreased (P &lt; 0.001) from 57.6 to 49.5. Multivariate analysis predicted a high preoperative FIB-4 index, high ALBI index, and hypo-CT attenuation value (&lt;30 HU) as risk factors for a high postoperative FIB-4 index. The FIB-4 index worsened when the follow-up period was only 6 months, regardless of the eternalness in the ALBI score. Liver fibrosis should be assessed using the FIB-4 index for a long-term survivorship after PD.

Evaluation of the dual vascular supply patterns in ground-glass nodules with a dynamic volume computed tomography.

BACKGROUNDIn recent years, the detection rate of ground-glass nodules (GGNs) has been improved dramatically due to the popularization of low-dose computed tomography (CT) screening with high-resolution CT technique. This presents challenges for the characterization and management of the GGNs, which depends on a thorough investigation and sufficient diagnostic knowledge of the GGNs. In most diagnostic studies of the GGNs, morphological manifestations are used to differentiate benignancy and malignancy. In contrast, few studies are dedicated to the assessment of the hemodynamics, i.e., perfusion parameters of the GGNs. AIMTo assess the dual vascular supply patterns of GGNs on different histopathology and opacities.METHODSForty-seven GGNs from 47 patients were prospectively included and underwent the dynamic volume CT. Histopathologic diagnoses were obtained within two weeks after the CT examination. Blood flow from the bronchial artery [bronchial flow (BF)] and pulmonary artery [pulmonary flow (PF)] as well as the perfusion index (PI) = [PF/(PF + BF)] were obtained using first-pass dual-input CT perfusion analysis and compared respectively between different histopathology and lesion types (pure or mixed GGNs) and correlated with the attenuation values of the lesions using one-way ANOVA, student’s t test and Pearson correlation analysis.RESULTSOf the 47 GGNs (mean diameter, 8.17 mm; range, 5.3-12.7 mm), 30 (64%) were carcinoma, 6 (13%) were atypical adenomatous hyperplasia and 11 (23%) were organizing pneumonia. All perfusion parameters (BF, PF and PI) demonstrated no significant difference among the three conditions (all P > 0.05). The PFs were higher than the BFs in all the three conditions (all P < 0.001). Of the 30 GGN carcinomas, 14 showed mixed GGNs and 16 pure GGNs with a higher PI in the latter (P < 0.01). Of the 17 benign GGNs, 4 showed mixed GGNs and 13 pure GGNs with no significant difference of the PI between the GGN types (P = 0.21). A negative correlation (r = -0.76, P < 0.001) was demonstrated between the CT attenuation values and the PIs in the 30 GGN carcinomas. CONCLUSIONThe GGNs are perfused dominantly by the PF regardless of its histopathology while the weight of the BF in the GGN carcinomas increases gradually during the progress of its opacification.

Single-material beam hardening correction via an analytical energy response model for diagnostic CT.

Various clinical studies show the potential for a wider quantitative role of diagnostic X-ray computed tomography (CT) beyond size measurements. Currently, the clinical use of attenuation values is, however, limited due to their lack of robustness. This issue can be observed even on the same scanner across patient size and positioning. There are different causes for the lack of robustness in the attenuation values; one possible source of error is beam hardening of the X-ray source spectrum. The conventional and well-established approach to address this issue is a calibration-based single material beam hardening correction (BHC) using a watercylinder. We investigate an alternative approach for single-material BHC with the aim of producing a more robust result for the attenuation values. The underlying hypothesis of this investigation is that calibration-based BHC automatically corrects for scattered radiation in a manner that is suboptimal in terms of bias as soon as the scanned object strongly deviates from the water cylinder used for calibration. The approach we propose performs BHC via an analytical energy response model that is embedded into a correction pipeline that efficiently estimates and subtracts scattered radiation in a patient-specific manner prior to BHC. The estimation of scattered radiation is based on minimizing, in average, the squared difference between our corrected data and the vendor-calibrated data. The used energy response model is considering the spectral effects of the detector response and the prefiltration of the source spectrum, including a beam-shaping bowtie filter. The performance of the correction pipeline is first characterized with computer simulated data. Afterward, it is tested using real 3-D CT data sets of two different phantoms, with various kV settings and phantom positions, assuming a circular data acquisition. The results are compared in the image domain to those from thescanner. For experiments with a water cylinder, the proposed correction pipeline leads to similar results as the vendor. For reconstructions of a QRM liver phantom with extension ring, the proposed correction pipeline achieved a more uniform and stable outcome in the attenuation values of homogeneous materials within the phantom. For example, the root mean squared deviation between centered and off-centered phantom positioning was reduced from 6.6 to 1.8HU in oneprofile. We have introduced a patient-specific approach for single-material BHC in diagnostic CT via the use of an analytical energy response model. This approach shows promising improvements in terms of robustness of attenuation values for large patient sizes. Our results contribute toward improving CT images so as to make CT attenuation values more reliable for use in clinicalpractice.

Diagnostic accuracy of CT Hounsfield unit in distinguishing Exudative and Transudative Pleural Effusion

Background: Differentiation of exudative and transudative types of pleural effusion is crucial for management of patients. Currently, this differentiation is done with the help of biochemical analysis of the aspirated fluid after thoracentesis, which is an invasive procedure. Objective: To evaluate the utility of CT attenuation values in pleural effusion and define a threshold value to differentiate between exudative and transudative pleural effusion. Materials &amp; Methods: A cross sectional study was done on 130 patients showing pleural effusion on CT thorax, mean attenuation was calculated using nine regions of interest on three slices. Within 48 hours of imaging, biochemical assessment was done to decide exudative or transudative nature of fluid as per Light’s criteria. A Receiver operating characteristic curve was drawn to assess the cut off CT attenuation value for distinguishing between exudative and transudative effusion and evaluate its accuracy. Result: Mean CT attenuation value of 57 exudative effusion cases was 5.9 + 6.48 HU, which was higher than 73 cases with transudative pleural effusion (2.97 + 2.69 HU). The difference was statistically significant (p value &lt; 0.0001). The ROC curve revealed a cut off value of 7.5 HU. When the mean CT attenuation value was &gt; 7.5 HU, the specificity and sensitivity of CT scan for diagnosing exudative effusion was 98.6 % and 59.6% respectively. Area under the curve was 0.79, which revealed moderate accuracy of this threshold value. Conclusion: CT attenuation values have moderate accuracy in differentiating between exudative and transudative pleural effusion.

Prognostic value of pericoronary adipose tissue attenuation in patients with non-alcoholic fatty liver disease with suspected coronary artery disease

Pericoronary adipose tissue (PCAT) attenuation on coronary computed tomography angiography (CTA) has been emerged as a marker of pericoronary inflammation. We aimed to investigate the prognostic value of PCAT attenuation in patients with non-alcoholic fatty liver disease (NAFLD). We enrolled 232 NAFLD patients with suspected coronary artery disease and underwent coronary CTA. NAFLD was defined by abdominal CT as the ratio of hepatic attenuation to spleen attenuation less than 1.0. PCAT attenuation values were assessed by the crude analysis of mean CT attenuation value of the left anterior descending artery (LAD) and right coronary artery (RCA). As coronary CTA findings, luminal stenosis and high-risk plaque features were examined. Primary outcome was the composite of cardiovascular (CV) death, nonfatal acute coronary syndrome, and hospitalization for heart failure. During a median follow-up of 4.9years, 17 patients had CV events. LAD-PCAT attenuation in patients with CV events was higher than that without CV events (-66.9 ± 7.0 versus -70.5 ± 6.6; p = 0.032), while RCA-PCAT attenuation was not. LAD-PCAT attenuation and high-risk plaque features were independent predictors of CV events. The addition of LAD-PCAT attenuation to high-risk plaque features increased the C-statistics and global chi-square from 0.66 to 0.75 (p = 0.042) and 6.8 to 12.7 (p = 0.015), respectively. The net reclassification achieved by adding LAD-PCAT attenuation to high-risk plaque features was 0.494 (p = 0.041). High-LAD-PCAT attenuation was an independent predictor of CV events in NAFLD patients, regardless of CTA-verified high-risk plaque features. In addition, LAD-PCAT attenuation had an incremental prognostic value over high-risk plaque features.

Primary malignant melanoma of the esophagus: differentiation from esophageal squamous cell carcinoma and leiomyoma using dynamic contrast-enhanced CT findings

PurposeThis study aimed to summarize the computed tomography (CT) findings of PMME and differentiate it from esophageal SCC and leiomyoma using CT analysis.MethodsThis was a retrospective study including 23 patients with PMME, 69 patients with SCC, and 21 patients with leiomyoma in our hospital. Qualitative CT morphological characteristics of each lesion included the location, tumor range, ulcer, enhanced pattern, and so on. For quantitative CT analysis, thickness, length and area of tumor, size of largest lymph node, number of metastatic lymph node, and CT value of tumor in plain, arterial, and delayed phases were measured. The associated factors for differentiating PMME from SCC and leiomyoma were examined with univariate and multivariate analysis. Receive operating characteristic curve (ROC) was used to determine the performance of CT models in discriminating PMME from SCC and leiomyoma.ResultsThe thickness, mean CT value in arterial phase, and range of tumor were the independent factors for diagnosing PMME from SCC. These parameters were used to establish a diagnostic CT model with area under the ROC (AUC) of 0.969, and accuracy of 90.2%. In pathology, interstitial vessels in PMME were more abundant than that of SCC, and the stromal fibrosis was more obvious in SCC. PMME commonly exhibited intraluminal expansively growth pattern and SCC often showed infiltrative pattern. The postcontrast attenuation difference in maximum CT attenuation value between plain and arterial phases was the independent factor for diagnosing PMME from leiomyoma. This parameter was applied to differentiate PMME from leiomyoma with AUC of 0.929 and accuracy of 86.4%.ConclusionThe qualitative and quantitative CT analysis had excellent performance for differentiating PMME from SCC and esophageal leiomyoma.Graphical abstract

Prediction of Sacral Screw Loosening after Lumbosacral Surgeries Involving Rigid Fixation of Sacral Bone Using Preoperative Computed Tomography Scans.

Objective To find a preoperative computed tomography-based method to predict the incidence of sacral screw loosening and assist surgical planning. Methods Surgically treated patients for degenerative lumbosacral disorders with rigid pedicle screw fixation of patients with L5-S1 vertebra in our center from January 2016 to January 2021 were retrospectively included in the current study. CT scan attenuation of the horizontal plane of the sacrum was measured with Hounsfield units (HU). Postoperative X-ray tests were used to diagnose screw loosening. The data was analyzed by independent sample t-tests, X2 analysis, Pearson correlation analysis, and ROC curve analysis. Results A total of 162 (114 male, 48 female, average age 63.7 ± 7.3 years) patients were included in the final analysis. Significant differences were found between the screw loosening group and nonloosening group concerning the HU value of the sacrum at the horizontal plane (P < 0.01). In ROC curve analysis, AUC was 0.674 (95% CI: 0.592-0.756). A cutoff of 200 HU provided 64.8% sensitivity and 62.4% specificity, and a cutoff of 150 HU provided 90.2% sensitivity. Conclusions Analyzing 162 patients with at least 12 months of follow-up, we propose cutoff CT attenuation values of 200 HU and 150 HU to take moderate and radical measures of screw augmentation to prevent screw loosening in the sacral bone.

Can lymphovascular invasion be predicted by contrast-enhanced CT imaging features in patients with esophageal squamous cell carcinoma? A preliminary retrospective study

BackgroundTo investigate the value of contrast-enhanced CT (CECT)-derived imaging features in predicting lymphovascular invasion (LVI) status in esophageal squamous cell carcinoma (ESCC) patients.MethodsOne hundred and ninety-seven patients with postoperative pathologically confirmed esophageal squamous cell carcinoma treated in our hospital between January 2017 and January 2019 were enrolled in our study, including fifty-nine patients with LVI and one hundred and thirty-eight patients without LVI. The CECT-derived imaging features of all patients were analyzed. The CECT-derived imaging features were divided into quantitative features and qualitative features. The quantitative features consisted of the CT attenuation value of the tumor (CTVTumor), the CT attenuation value of the normal esophageal wall (CTVNormal), the CT attenuation value ratio of the tumor-to-normal esophageal wall (TNR), the CT attenuation value difference between the tumor and normal esophageal wall (ΔTN), the maximum thickness of the tumor measured by CECT (Thickness), the maximum length of the tumor measured by CECT (Length), and the gross tumor volume measured by CECT (GTV). The qualitative features consisted of an enhancement pattern, tumor margin, enlarged blood supply or drainage vessels to the tumor (EVFDT), and tumor necrosis. For the clinicopathological characteristics and CECT-derived imaging feature analysis, the chi-squared test was used for categorical variables, the Mann–Whitney U test was used for continuous variables with a nonnormal distribution, and the independent sample t-test was used for the continuous variables with a normal distribution. The trend test was used for ordinal variables. The association between LVI status and CECT-derived imaging features was analyzed by univariable logistic analysis, followed by multivariable logistic regression and receiver operating characteristic (ROC) curve analysis.ResultsThe CTVTumor, TNR, ΔTN, Thickness, Length, and GTV in the group with LVI were higher than those in the group without LVI (P < 0.05). A higher proportion of patients with heterogeneous enhancement pattern, irregular tumor margin, EVFDT, and tumor necrosis were present in the group with LVI (P < 0.05). As revealed by the univariable logistic analysis, the CECT-derived imaging features, including CTVTumor, TNR, ΔTN and enhancement pattern, Thickness, Length, GTV, tumor margin, EVFDT, and tumor necrosis were associated with LVI status (P < 0.05). Only the TNR (OR 8.655; 95% CI 2.125–37.776), Thickness (OR 6.531; 95% CI 2.410–20.608), and tumor margin (OR 4.384; 95% CI 2.004–9.717) were independent risk factors for LVI in the multivariable logistic regression analysis. The ROC curve analysis incorporating the above three CECT-derived imaging features showed that the area under the curve obtained by the multivariable logistic regression model was 0.820 (95% CI 0.754–0.885).ConclusionThe CECT-derived imaging features, including TNR, Thickness, tumor margin, and their combination, can be used as predictors of LVI status for patients with ESCC.

Radiological Signs of Urinary Tract Involvement in Covid-19

The extrapulmonary manifestations of Coronavirus Disease 2019 (COVID-19) are common. However, radiological reports presenting urinary tract abnormalities related to COVID-19 were not widely published. We present a case of a female patient with a mild course of the COVID-19 disease, which affected the entire urinary tract. CT scanning showed inflammatory kidney changes with multiple ureter and bladder blood clots accompanied by a decrease in renal function. A literature review found only several publications that included imaging of urinary tract manifestations of COVID-19, generally presenting as renal infarctions due to a COVID-19 related hypercoagulability state. Also, there is evidence of some discrete changes in renal parenchymal CT attenuation values due to kidney inflammation in COVID-19 patients. However, imaging of other parts of the urinary system, with the exception of the kidneys, are rarely described to be affected by COVID-19. More clinical attention is needed to diagnose the unknown aspects of the disease.

Comparison of L1 CT-attenuation and cortical thickness in predicting osteoporosis by opportunistic CT.

In vertebrae, the amount of cortical bone has been estimated at 30-60%, but 45-75% of axial load on a vertebral body is borne by cortical bone. To compare the role of L1 CT-attenuation and cortical thickness in predicting osteoporosis by opportunistic CT and explore cortical thickness value in osteoporosis. We collected data of 94 patients who underwent DXA and thoracic and/or abdominal CT to demonstrate an entire L1 for other indications in routine practice. Patients were divided into three groups according to T-score: osteoporosis, osteopenia, or normal. CT-attenuation value and cortical thickness of L1 were measured. ANOVA analysis was utilized to analyze CT-attenuation and cortical thickness among the three groups. Sensitivity, specificity, and area under the curve (AUC) predicting low BMD were determined using ROC. Pearson correlations were employed to describe relationship between L1 BMD and CT-attenuation value, BMD, as well as cortical thickness. The mean cortical thickness was 0.83±0.11, 0.72±0.10, and 0.64±0.09 mm for normal, osteopenia, and osteoporotic subgroups, respectively. A statistically significant difference was observed in cortical thickness and CT-attenuation value among these three subgroups. A mean CT-attenuation value threshold of > 148.7 yielded 73.0% sensitivity and 86.0% specificity for distinguishing low BMD from normal with an AUC = 0.83. Pearson correlation analysis indicated that BMD was positively correlated with CT-attenuation (r = 0.666, P < 0.001) and cortical thickness (r = 0.604, P < 0.001). L1 CT-attenuation and cortical thickness measured on opportunistic CT can help predict osteoporosis. Compared with cortical thickness, CT-attenuation is a more sensitive and accurate index for distinguishing low BMD from normal.