How subjective CT image quality assessment becomes surprisingly reliable: pairwise comparisons instead of Likert scale.

OBJECTIVES: The aim of this study is to improve the reliability of subjective IQ assessment using a pairwise comparison (PC) method instead of a Likert scale method in abdominal CT scans. METHODS: Abdominal CT scans (single-center) were retrospectively selected between September 2019 and February 2020 in a prior study. Sample variance in IQ was obtained by adding artificial noise using dedicated reconstruction software, including reconstructions with filtered backprojection and varying iterative reconstruction strengths. Two datasets (each n = 50) were composed with either higher or lower IQ variation with the 25 original scans being part of both datasets. Using in-house developed software, six observers (five radiologists, one resident) rated both datasets via both the PC method (forcing observers to choose preferred scans out of pairs of scans resulting in a ranking) and a 5-point Likert scale. The PC method was optimized using a sorting algorithm to minimize necessary comparisons. The inter- and intraobserver agreements were assessed for both methods with the intraclass correlation coefficient (ICC). RESULTS: Twenty-five patients (mean age 61 years ± 15.5; 56% men) were evaluated. The ICC for interobserver agreement for the high-variation dataset increased from 0.665 (95%CI 0.396-0.814) to 0.785 (95%CI 0.676-0.867) when the PC method was used instead of a Likert scale. For the low-variation dataset, the ICC increased from 0.276 (95%CI 0.034-0.500) to 0.562 (95%CI 0.337-0.729). Intraobserver agreement increased for four out of six observers. CONCLUSION: The PC method is more reliable for subjective IQ assessment indicated by improved inter- and intraobserver agreement. CLINICAL RELEVANCE STATEMENT: This study shows that the pairwise comparison method is a more reliable method for subjective image quality assessment. Improved reliability is of key importance for optimization studies, validation of automatic image quality assessment algorithms, and training of AI algorithms. KEY POINTS: • Subjective assessment of diagnostic image quality via Likert scale has limited reliability. • A pairwise comparison method improves the inter- and intraobserver agreement. • The pairwise comparison method is more reliable for CT optimization studies.

Pretreatment Interstitial Lung Abnormalities Detected on Abdominal Computed Tomography Scans in Prostate Cancer Patients.

OBJECTIVE: Prostate cancer and interstitial lung abnormality (ILA) share similar risk factor, which is men and older age. The purpose of this study was to investigate the prevalence of pretreatment ILA among prostate cancer patients who underwent abdominal computed tomography (CT) within 1 year at their first visit to the urology department. In addition, we aimed to assess the association between pretreatment ILA and long-term survival in prostate cancer patients. METHODS: This study was conducted in patients who had a first visit for prostate cancer at urology department between 2005 and 2016 and underwent an abdominal CT within 1 year. A thoracic radiologist evaluated the presence of ILA through inspecting the lung base scanned on an abdominal CT. The association between pretreatment ILA and survival was assessed using Kaplan-Meier analysis with log-rank test. Specific survival rates at 12, 36, and 60 months according to the presence of ILA were evaluated using z -test. Cox regression analysis was used to assess the risk factors of mortality. RESULTS: A total of 173 patients were included (mean age, 70.23 ± 7.98 years). Pretreatment ILA was observed in 10.4% of patients. Patients with ILA were more likely to be older and current smokers. Pretreatment ILA was associated with poor survival ( P < 0.001). Age ≥70 years (hazards ratio [HR], 1.98; 95% confidence interval [CI], 1.24-3.16; P = 0.004), metastatic stage (HR, 2.26; 95% CI, 1.36-3.74; P = 0.002), and ILA (HR, 1.96; 95% CI, 1.06-3.60; P = 0.031) were the independent risk factors of mortality. An ILA (HR, 3.94; 95% CI, 1.78-8.72; P = 0.001) was the only independent risk factor of mortality in localized stage prostate cancer patients. CONCLUSIONS: This study provides important insights into the unexplored effect of pretreatment ILA in prostate cancer patients. Pretreatment ILAs were observed considerably in the lung bases scanned on the abdominal CT scans among prostate cancer patients. Furthermore, pretreatment ILAs were the risk factor of mortality. Therefore, lung bases should be routinely inspected in the abdominal CT scans of prostate cancer patients. This result may help clinicians in establishing personalized management strategy of prostate cancer patients.

Deep learning image reconstruction generates thinner slice iodine maps with improved image quality to increase diagnostic acceptance and lesion conspicuity: a prospective study on abdominal dual-energy CT.

BACKGROUND: To assess the improvement of image quality and diagnostic acceptance of thinner slice iodine maps enabled by deep learning image reconstruction (DLIR) in abdominal dual-energy CT (DECT). METHODS: This study prospectively included 104 participants with 136 lesions. Four series of iodine maps were generated based on portal-venous scans of contrast-enhanced abdominal DECT: 5-mm and 1.25-mm using adaptive statistical iterative reconstruction-V (Asir-V) with 50% blending (AV-50), and 1.25-mm using DLIR with medium (DLIR-M), and high strength (DLIR-H). The iodine concentrations (IC) and their standard deviations of nine anatomical sites were measured, and the corresponding coefficient of variations (CV) were calculated. Noise-power-spectrum (NPS) and edge-rise-slope (ERS) were measured. Five radiologists rated image quality in terms of image noise, contrast, sharpness, texture, and small structure visibility, and evaluated overall diagnostic acceptability of images and lesion conspicuity. RESULTS: The four reconstructions maintained the IC values unchanged in nine anatomical sites (all p > 0.999). Compared to 1.25-mm AV-50, 1.25-mm DLIR-M and DLIR-H significantly reduced CV values (all p < 0.001) and presented lower noise and noise peak (both p < 0.001). Compared to 5-mm AV-50, 1.25-mm images had higher ERS (all p < 0.001). The difference of the peak and average spatial frequency among the four reconstructions was relatively small but statistically significant (both p < 0.001). The 1.25-mm DLIR-M images were rated higher than the 5-mm and 1.25-mm AV-50 images for diagnostic acceptability and lesion conspicuity (all P < 0.001). CONCLUSIONS: DLIR may facilitate the thinner slice thickness iodine maps in abdominal DECT for improvement of image quality, diagnostic acceptability, and lesion conspicuity.

Generation of virtual monoenergetic images at 40 keV of the upper abdomen and image quality evaluation based on generative adversarial networks.

BACKGROUND: Abdominal CT scans are vital for diagnosing abdominal diseases but have limitations in tissue analysis and soft tissue detection. Dual-energy CT (DECT) can improve these issues by offering low keV virtual monoenergetic images (VMI), enhancing lesion detection and tissue characterization. However, its cost limits widespread use. PURPOSE: To develop a model that converts conventional images (CI) into generative virtual monoenergetic images at 40 keV (Gen-VMI40keV) of the upper abdomen CT scan. METHODS: Totally 444 patients who underwent upper abdominal spectral contrast-enhanced CT were enrolled and assigned to the training and validation datasets (7:3). Then, 40-keV portal-vein virtual monoenergetic (VMI40keV) and CI, generated from spectral CT scans, served as target and source images. These images were employed to build and train a CI-VMI40keV model. Indexes such as Mean Absolute Error (MAE), Peak Signal-to-Noise Ratio (PSNR), and Structural Similarity (SSIM) were utilized to determine the best generator mode. An additional 198 cases were divided into three test groups, including Group 1 (58 cases with visible abnormalities), Group 2 (40 cases with hepatocellular carcinoma [HCC]) and Group 3 (100 cases from a publicly available HCC dataset). Both subjective and objective evaluations were performed. Comparisons, correlation analyses and Bland-Altman plot analyses were performed. RESULTS: The 192nd iteration produced the best generator mode (lower MAE and highest PSNR and SSIM). In the Test groups (1 and 2), both VMI40keV and Gen-VMI40keV significantly improved CT values, as well as SNR and CNR, for all organs compared to CI. Significant positive correlations for objective indexes were found between Gen-VMI40keV and VMI40keV in various organs and lesions. Bland-Altman analysis showed that the differences between both imaging types mostly fell within the 95% confidence interval. Pearson's and Spearman's correlation coefficients for objective scores between Gen-VMI40keV and VMI40keV in Groups 1 and 2 ranged from 0.645 to 0.980. In Group 3, Gen-VMI40keV yielded significantly higher CT values for HCC (220.5HU vs. 109.1HU) and liver (220.0HU vs. 112.8HU) compared to CI (p < 0.01). The CNR for HCC/liver was also significantly higher in Gen-VMI40keV (2.0 vs. 1.2) than in CI (p < 0.01). Additionally, Gen-VMI40keV was subjectively evaluated to have a higher image quality compared to CI. CONCLUSION: CI-VMI40keV model can generate Gen-VMI40keV from conventional CT scan, closely resembling VMI40keV.

Yield of abdominal radiographs in children with suspected intussusception; rate of pneumoperitoneum and other abdominal pathology.

OBJECTIVES: Ultrasound is the criterion standard imaging modality for the diagnosis of intussusception. However, to our knowledge the utility of abdominal radiographs to concurrently screen for pneumoperitoneum or other abdominal pathology that could have a similar presentation has not been studied. Our institutional protocol requires the performance of AP supine and left lateral decubitus views of the abdomen prior to ultrasound evaluation for intussusception, providing an opportunity to examine the yield of abdominal radiographs in this setting. Our primary objective was to determine the rate of pneumoperitoneum on screening abdominal radiographs in children undergoing evaluation for intussusception. Our secondary objective was to determine the rate that other clinically significant pathology is found on these screening abdominal radiographs. METHODS: We performed a retrospective chart review of all patients under 6 years of age who had any imaging ordered in our large urban pediatric emergency department to evaluate for suspected intussusception during the calendar years 2018-2020. RESULTS: 1115 patient encounters met our inclusion criteria. Among 1090 who had screening abdominal radiographs, 82 (8%) had findings concerning for intussusception. Of those not concerning for intussusception, 635 (58%) were read as normal, 263 (24%) showed moderate to large stool burden, 107 (10%) showed generalized bowel distention, and 22 (2%) showed abnormal gastric distention. Individually the remainder of all other findings compromised <1% of encounters and included radiopaque foreign body (8), intraabdominal calcification (4), pneumonia/effusion (3), pneumatosis intestinalis, abdominal mass (2), diaphragmatic hernia (1), rib fracture (1), appendicolith (1), feeding tube malposition (1), and bowel wall thickening (1). In one encounter the patient had a bowel perforation with pneumoperitoneum present secondary to ingestion of multiple magnets. CONCLUSIONS: Our study indicates that radiograph-detected pneumoperitoneum is rare in children with suspected intussusception. Constipation is the most common abnormal finding on screening radiographs. Other findings occur in approximately 15% of total cases, some of which require further workup.

Comparative study of abdominal CT enhancement in overweight and obese patients based on different scanning modes combined with different contrast medium concentrations.

PURPOSE: To compare image quality, iodine intake, and radiation dose in overweight and obese patients undergoing abdominal computed tomography (CT) enhancement using different scanning modes and contrast medium. METHODS: Ninety overweight and obese patients (25 kg/m2≤body mass index (BMI)< 30 kg/m2 and BMI≥30 kg/m2) who underwent abdominal CT-enhanced examinations were randomized into three groups (A, B, and C) of 30 each and scanned using gemstone spectral imaging (GSI) +320 mgI/ml, 100 kVp + 370 mgI/ml, and 120 kVp + 370 mgI/ml, respectively. Reconstruct monochromatic energy images of group A at 50-70 keV (5 keV interval). The iodine intake and radiation dose of each group were recorded and calculated. The CT values, contrast-to-noise ratios (CNRs), and subjective scores of each subgroup image in group A versus images in groups B and C were by using one-way analysis of variance or Kruskal-Wallis H test, and the optimal keV of group A was selected. RESULTS: The dual-phase CT values and CNRs of each part in group A were higher than or similar to those in groups B and C at 50-60 keV, and similar to or lower than those in groups B and C at 65 keV and 70 keV. The subjective scores of the dual-phase images in group A were lower than those of groups B and C at 50 keV and 55 keV, whereas no significant difference was seen at 60-70 keV. Compared to groups B and C, the iodine intake in group A decreased by 12.5% and 13.3%, respectively. The effective doses in groups A and B were 24.7% and 25.8% lower than those in group C, respectively. CONCLUSION: GSI +320 mgI/ml for abdominal CT-enhanced in overweight patients satisfies image quality while reducing iodine intake and radiation dose, and the optimal keV was 60 keV.

Utilizing ultrasound in suspected necrotizing enterocolitis with equivocal radiographic findings.

BACKGROUND: To examine the use of abdominal ultrasound (AUS) as a diagnostic adjunct in the diagnosis of necrotizing enterocolitis (NEC) in cases where abdominal radiography (AXR) is equivocal in order to reduce unnecessary antibiotic use in neonates. METHODS: Retrospective study (2017-2019) of infants undergoing NEC evaluation with equivocal AXR findings (n = 54). Paired AXR and AUS were reviewed with respect to presence or absence of pneumatosis. Concordance of AUS findings with decision to treat for NEC was evaluated. RESULTS: Among 54 infants where AXR was equivocal, AUS demonstrated presence of pneumatosis in 22 patients (41%), absence of pneumatosis in 31 patients (57%), and was equivocal in 1 patient. All patients with pneumatosis on AUS were treated for NEC. Of 31 patients without pneumatosis on AUS, 25 patients (78%) were not treated for NEC. Patients without pneumatosis on AUS received a significantly shorter mean duration of antibiotics compared to those with pneumatosis (3.3 days (+/- 4.8 days) vs 12.4 days (+/- 4.7 days)); p < 0.001). Of those patients not treated, none required treatment within 1 week following negative AUS. CONCLUSION: AUS is a valuable tool for evaluating the presence or absence of pneumatosis in the setting of equivocal AXR. Absence of pneumatosis on AUS informs clinical decision making and reduces unnecessary treatment and antibiotic usage.

Early Prediction of Acute Biliary Pancreatitis Using Clinical and Abdominal CT Features.

Background Assessment of the biliary origin of acute pancreatitis (AP) is crucial because it affects patient treatment to avoid recurrence. Although CT is systematically performed to determine severity in AP, its usefulness in assessing AP biliary origin has not been evaluated. Purpose To assess abdominal CT features associated with acute biliary pancreatitis (ABP) and to evaluate the predictive value of a combination of CT and clinical data for determining a biliary origin in a first episode of AP. Materials and Methods From December 2014 to May 2019, all consecutive patients who presented with a first episode of AP and with at least 6 months of follow-up were retrospectively reviewed. Evidence of gallstones was mandatory for a clinical diagnosis of ABP. Abdominal CT images were reviewed by two abdominal radiologists. Univariable and multivariable statistical analyses were performed, and a nomogram was constructed on the basis of the combination of clinical and CT features. This nomogram was validated in a further independent internal cohort of patients. Results A total of 271 patients (mean age ± standard deviation, 56 years ± 20; 160 men) were evaluated. Of these, 170 (63%) had ABP. At multivariable analysis, age (odds ratio [OR], 1.06; 95% CI: 1.03, 1.09; P < .001), alanine aminotransferase level (OR, 1.00; 95% CI: 1.00, 1.01; P = .009), gallbladder gallstone (OR, 15.59; 95% CI: 4.61, 68.62; P < .001), choledochal ring sign (OR, 5.73; 95% CI: 2.11, 17.05; P < .001), liver spontaneous attenuation (OR, 1.07; 95% CI: 1.04, 1.11; P < .001), and duodenal thickening (OR, 0.17; 95% CI: 0.03, 0.61; P = .01) were independently associated with ABP. The matching nomogram combining both clinical and CT features displayed an area under the curve of 0.94 (95% CI: 0.91, 0.97) in the study sample (n = 271) and 0.91 (95% CI: 0.84, 0.99) in the validation cohort (n = 51). Conclusion Abdominal CT provided useful features for diagnosis of acute biliary pancreatitis (ABP). Combining CT and clinical features in a nomogram showed good diagnostic performance for early diagnosis of ABP. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Chang in this issue.

Comparative Safety of Endoscopic vs Radiological Gastrostomy Tube Placement: Outcomes From a Large, Nationwide Veterans Affairs Database.

INTRODUCTION: A gastrostomy is generally performed in patients who are unable to maintain volitional intake of food. We compared outcomes of percutaneous endoscopic gastrostomy (PEG) and interventional radiologist-guided gastrostomy (IRG) using an integrated nationwide database. METHODS: Using the VA Informatics and Computing Infrastructure database, patients who underwent PEG or IRG from 2011 through 2021 were selected using Current Procedural Terminology and International Classification of Diseases codes. The primary outcome was the comparative incidence of adverse events between PEG and IRG. Secondary outcomes included all-cause mortality. Comorbidities were identified using International Classification of Diseases codes, and adjusted odds ratio (OR) for adverse events were calculated using multivariate logistic regression analysis. RESULTS: A total of 23,566 (70.7 ± 10.2 years) patients underwent PEG and 9,715 (69.6 ± 9.7 years) underwent IRG. Selected frequent indications for PEG vs IRG were as follows: stroke, 6.8% vs 5.3%, P < 0.01; aspiration pneumonia, 10.9% vs 6.8%, P < 0.001; feeding difficulties, 9.8% vs 6.3%, P < 0.01; and upper aerodigestive tract malignancies 58.8% vs 79.8%, P < 0.01. Across all subtypes of malignancies of the head and neck and foregut, the proportion of patients undergoing IRG was greater than those undergoing PEG (P < 0.001). The all-cause 30-day mortality and overall incidence of adverse events were significantly lower for PEG compared with those for IRG (PEG vs IRG): all-cause 30-day mortality, 9.35% vs 10.3% (OR 0.80; 95% confidence interval [CI] 0.74-0.87; P < 0.01); perforation of the colon, 0.12% vs 0.24% (OR 0.50; 95% CI 0.29-0.86; P = 0.04); peritonitis, 1.9% vs 2.7% (OR 0.68; 95% CI 0.58-0.79; P < 0.01); and hemorrhage 1.6% vs 1% (OR 1.47; 95% CI 1.18-1.83; P < 0.01). DISCUSSION: In a large nationwide database of more than 33,000 gastrostomy procedures, PEG was associated with a lower incidence of adverse outcomes and the 30-day mortality than IRG.

Development and Validation of a Radiomics Model for Differentiating Bone Islands and Osteoblastic Bone Metastases at Abdominal CT.

Background It is important to diagnose sclerotic bone lesions in order to determine treatment strategy. Purpose To evaluate the diagnostic performance of a CT radiomics-based machine learning model for differentiating bone islands and osteoblastic bone metastases. Materials and Methods In this retrospective study, patients who underwent contrast-enhanced abdominal CT and were diagnosed with a bone island or osteoblastic metastasis between 2015 to 2019 at either of two different institutions were included: institution 1 for the training set and institution 2 for the external test set. Radiomics features were extracted. The random forest (RF) model was built using 10 selected features, and subsequent 10-fold cross-validation was performed. In the test phase, the RF model was tested with an external test set. Three radiologists reviewed the CT images for the test set. The sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) were calculated for the models and each of the three radiologists. The AUCs of the radiomics model and radiologists were compared. Results A total of 177 patients (89 with a bone island and 88 with metastasis; mean age, 66 years ± 12 [standard deviation]; 111 men) were in the training set, and 64 (23 with a bone island and 41 with metastasis; mean age, 69 years ± 14; 59 men) were in the test set. Radiomics features (n = 1218) were extracted. The average AUC of the RF model from 10-fold cross-validation was 0.89 (sensitivity, 85% [75 of 88 patients]; specificity, 82% [73 of 89 patients]; and accuracy, 84% [148 of 177 patients]). In the test set, the AUC of the trained RF model was 0.96 (sensitivity, 80% [33 of 41 patients]; specificity, 96% [22 of 23 patients]; and accuracy, 86% [55 of 64 patients]). The AUCs for the three readers were 0.95 (95% CI: 0.90, 1.00), 0.96 (95% CI: 0.90, 1.00), and 0.88 (95% CI: 0.80, 0.96). The AUC of radiomics model was higher than that of only reader 3 (0.96 vs 0.88, respectively; P = .03). Conclusion A CT radiomics-based random forest model was proven useful for differentiating bone islands from osteoblastic metastases and showed better diagnostic performance compared with an inexperienced radiologist. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Vannier in this issue.

Population-Scale CT-based Body Composition Analysis of a Large Outpatient Population Using Deep Learning to Derive Age-, Sex-, and Race-specific Reference Curves.

Background Although CT-based body composition (BC) metrics may inform disease risk and outcomes, obtaining these metrics has been too resource intensive for large-scale use. Thus, population-wide distributions of BC remain uncertain. Purpose To demonstrate the validity of fully automated, deep learning BC analysis from abdominal CT examinations, to define demographically adjusted BC reference curves, and to illustrate the advantage of use of these curves compared with standard methods, along with their biologic significance in predicting survival. Materials and Methods After external validation and equivalency testing with manual segmentation, a fully automated deep learning BC analysis pipeline was applied to a cross-sectional population cohort that included any outpatient without a cardiovascular disease or cancer who underwent abdominal CT examination at one of three hospitals in 2012. Demographically adjusted population reference curves were generated for each BC area. The z scores derived from these curves were compared with sex-specific thresholds for sarcopenia by using χ2 tests and used to predict 2-year survival in multivariable Cox proportional hazards models that included weight and body mass index (BMI). Results External validation showed excellent correlation (R = 0.99) and equivalency (P < .001) of the fully automated deep learning BC analysis method with manual segmentation. With use of the fully automated BC data from 12 128 outpatients (mean age, 52 years; 6936 [57%] women), age-, race-, and sex-normalized BC reference curves were generated. All BC areas varied significantly with these variables (P < .001 except for subcutaneous fat area vs age [P = .003]). Sex-specific thresholds for sarcopenia demonstrated that age and race bias were not present if z scores derived from the reference curves were used (P < .001). Skeletal muscle area z scores were significantly predictive of 2-year survival (P = .04) in combined models that included BMI. Conclusion Fully automated body composition (BC) metrics vary significantly by age, race, and sex. The z scores derived from reference curves for BC parameters better capture the demographic distribution of BC compared with standard methods and can help predict survival. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Summers in this issue.

Value of early second session shock wave lithotripsy in treatment of upper ureteric stones compared to laser ureteroscopy.

PURPOSE: The safety and efficacy of early second session shock wave lithotripsy (SWL) compared with laser ureteroscopy (URS) for the treatment of upper ureteric stones were evaluated. METHODS: From January to October 2019, 108 patients with upper ureteric stones (< 1.5 cm and ≤ 1000 Hounsfield unit (HU)) were randomized into SWL and laser URS groups. The second SWL session was performed within 48-72 h of the first session. Using plain abdominal X-ray and ultrasonography, patients were evaluated 48-72 h after the first SWL session and one week after the second and third SWL sessions or one week after URS. The procedure was considered a success when no additional procedures were needed to clear the stone. To determine the stone-free rate (SFR), noncontrast computed tomography of the urinary tract was performed three months postoperatively. RESULTS: In the SWL group, the success rates were 92.6% and 94.4% after the second and third sessions. The SFR was 96.2% in the laser URS group. The success rates were not significantly different between the second and third SWL sessions versus the laser URS (p = 0.418 and 0.660, respectively). Operative and fluoroscopy times were significantly longer in the SWL group (p = 0.001), and JJ stent insertions were needed after laser URS. CONCLUSION: Ultraslow full-power SWL treatment of patients with upper ureteric stones (< 1.5 cm and ≤ 1000 HU) with an early second session is safe and effective compared to laser URS. Patients who do not respond to early second SWL session should be shifted to another treatment modality.

Paravertebral Muscles as Indexes of Sarcopenia and Sarcopenic Obesity: Comparison With Imaging and Muscle Function Indexes and Impact on Cardiovascular and Metabolic Disorders.

OBJECTIVE. The objectives of this study were to propose the use of the cross-sectional area of paravertebral muscle (PMA) and the ratio of the PMA to the cross-sectional area of visceral fat (PVR) as new indexes of sarcopenia or sarcopenic obesity through comparison with existing indexes and to show the clinical associations of PMA and PVR with hypertension and diabetes. SUBJECTS AND METHODS. A total of 1270 participants (608 men and 662 women; mean [± SD] age, 63.57 ± 6.94 years) were recruited from a community-based population of elderly individuals. PMA and PVR were measured on single-slice abdominal CT images. Pearson correlation was used to evaluate the correlation of PMA and PVR with widely used imaging and muscle function indexes of sarcopenia and sarcopenic obesity. Tertile categories of PMA and PVR were evaluated to investigate associations with risks for hypertension and diabetes in men and women, by use of separate multivariable logistic regression models. RESULTS. PMA was correlated with the cross-sectional area of thigh muscle on CT, appendicular skeletal muscle mass (ASM) on dual-energy x-ray absorptiometry, height-adjusted ASM (calculated as ASM divided by the height in meters squared), and body mass index (BMI)-adjusted ASM (calculated as ASM divided by BMI) (p < .01). PMA was also correlated with hand grip strength and gait speeds (p < .01). PVR was correlated with height-adjusted ASM and BMI-adjusted ASM (p < .01). A high PVR significantly decreased the odds ratios for hypertension and diabetes in the unadjusted model and the model adjusted for age, smoking, and drinking status. The ratio of the cross-sectional area of thigh muscle to the cross-sectional area of visceral fat and the BMI-adjusted ASM produced results similar to those of PVR in terms of the odds ratios for hypertension and diabetes. CONCLUSION. Single-slice abdominal CT can supply PMA and visceral fat information together. PMA and PVR were found to be reliable indexes of sarcopenia and sarcopenic obesity. A high PVR was associated with low risks for hypertension and diabetes.

Deep-learning-based image reconstruction in dynamic contrast-enhanced abdominal CT: image quality and lesion detection among reconstruction strength levels.

AIM: To evaluate the use of deep-learning-based image reconstruction (DLIR) algorithms in dynamic contrast-enhanced computed tomography (CT) of the abdomen, and to compare the image quality and lesion conspicuity among the reconstruction strength levels. MATERIALS AND METHODS: This prospective study included 59 patients with 373 hepatic lesions who underwent dynamic contrast-enhanced CT of the abdomen. All images were reconstructed using four reconstruction algorithms, including 40% adaptive statistical iterative reconstruction-Veo (ASiR-V) and DLIR at low, medium, and high-strength levels (DLIR-L, DLIR-M, and DLIR-H, respectively). The signal-to-noise ratio (SNR) of the abdominal aorta, portal vein, liver, pancreas, and spleen and the lesion-to-liver contrast-to-noise ratio (CNR) were calculated and compared among the four reconstruction algorithms. The diagnostic acceptability was qualitatively assessed and compared among the four reconstruction algorithms and the conspicuity of hepatic lesions was compared between <5 and ≥5 mm lesions. RESULTS: The SNR of each anatomical structure (p<0.0001) and CNR (p<0.0001) were significantly higher in DLIR-H than the other reconstruction algorithms. Diagnostic acceptability was significantly better in DLIR-M than the other reconstruction algorithms (p<0.0001). The conspicuity of hepatic lesions was highest when using 40% ASiR-V and tended to lessen as the reconstruction strength level was getting higher in DLIR, especially in <5 mm lesions; however, all hepatic lesions could be detected. CONCLUSIONS: DLIR improved the SNR, CNR, and image quality compared with 40% ASiR-V, while making it possible to decrease lesion conspicuity using higher reconstruction strength.

Optimal diagnostic tool for surveillance of oesophageal varices during COVID-19 pandemic.

AIM: To study the diagnostic accuracy and utility of triphasic abdominal computed tomography (CT) in the diagnosis and grading of oesophageal varices (OVs) as an alternative to endoscopy during the COVID-19 pandemic. MATERIALS AND METHODS: A prospective analysis was undertaken of retrospective data from cirrhotic patients who underwent oesophago-gastro-duodenoscopy (OGD) and a triphasic abdominal CT from January to December 2019. Endoscopists and radiologists provided their respective independent assessment of OV grading after being blinded to the clinical details. Performance of CT grading of OVs was compared with the reference standard endoscopic grading using weighted kappa (k). Non-invasive scores such, as aspartate transaminase (AST)-to-platelet ratio index (APRI), Fibrosis-4 (FIB-4) Index, platelet: spleen (PS) ratio were correlated between the two techniques. RESULTS: OV grading between endoscopists and radiologists showed 81.73% agreement (85 out of 104 patients) in the comparative analysis of 104 cirrhotic patients, of which no varices (57.1%, n=4), small (85.1%, n=23), medium (72.2%%, n=26), and large varices (94.1%, n=32) with a weighted k score of 0.88 (95% confidence interval 0.82-0.94). Overall, the sensitivity of CT in the diagnosis of no, small, medium, and large OVs was 66.6%, 79.3%, 89.6%, and 94.1%, respectively, with an area under the receiver operating curve (AUROC) score of 0.775, 0.887, 0.839, and 0.914. Performance of APRI, FIB-4, and PS ratio correlated well with the severity of OVs with no difference between OGD and CT grading. CONCLUSION: Triphasic abdominal CT can be an invaluable tool in the diagnosis and grading of OVs during the COVID-19 pandemic.

Impact of Image Reconstruction Parameters on Abdominal Aortic Calcification Measurement Using Abdominal Computed Tomography.

BACKGROUND AND AIMS: Abdominal aortic calcification (AAC) is correlated with cardiovascular outcomes independent of traditional risk factors. Quantification of AAC on computed tomography (CT) has not been standardized. Reconstruction parameters have been shown to impact coronary calcium scores. The aim of our study was to assess the impact of abdominal CT reconstruction parameters, slice thickness (ST), and display field of view (DFOV) on AAC quantitative scoring on abdominal CT examinations. METHODS: We retrospectively measured AAC on noncontrast CT of 46 patients (mean age, 64.1 years; 35 males) using 5 different reconstruction protocols with a range of ST and DFOV: protocol A, 2.5 mm ST, 35 cm DFOV; protocol B, 2.5 mm ST, 50 cm DFOV; protocol C, 2.5 mm ST, 25 cm DFOV; protocol D, 5 mm ST, 35 cm DFOV; and protocol E: 0.625 mm ST, 35 cm DFOV. The AAC scores from each protocol were compared using concordance correlation coefficient and Bland-Altman agreement analyses. RESULTS: The AAC mean (SD) scores for each protocol were as follows: A, 2022 (2418); B, 2022 (2412); C, 1939 (2310); D, 2220 (2695); and E, 1862 (2234). The AAC mean score differences between protocols and reference protocol A were -0.47, 82.01, -198.94, and 160 for protocols B, C, D, and E, respectively, with differences between protocols C to E statistically significantly different (P < 0.05). The different protocols showed overall excellent correlation (concordance correlation coefficient, >0.9) between AAC scores. CONCLUSIONS: Slice thickness and DFOV can impact AAC score measurement. A description of reconstruction parameters is important to allow comparisons across different cohorts.

Can plain film radiography improve the emergency department detection of clinically important urinary stones?

OBJECTIVE: Physicians frequently use ultrasound to assess hydronephrosis in patients with suspected renal colic, but ultrasound has limited diagnostic sensitivity and rarely clarifies stone size or location. Consequently, up to 80% of emergency department (ED) renal colic patients undergo confirmatory CT imaging. Our goal was to estimate x-ray sensitivity for urinary stones and determine whether x-ray substantially improves stone detection (sensitivity) compared to hydronephrosis assessment alone. METHODS: We reviewed imaging reports from all renal colic patients who underwent x-ray and CT at four EDs. For each patient, we documented stone size, location and hydronephrosis severity on CT and whether stones were identified on x-ray. We considered moderate and severe hydronephrosis (MS-Hydro) as significant positive findings, then calculated the sensitivity (detection rate) of MS-Hydro and x-ray for large stones ≥5 mm and for stones likely to require intervention (all ureteral stones >7 mm and proximal or middle stones >5 mm). We then tested a diagnostic algorithm adding x-ray to hydronephrosis assessment. RESULTS: Among 1026 patients with 1527 stones, MS-Hydro sensitivity was 39% for large stones and 60% for interventional stones. X-ray sensitivity was 46% for large stones and 52% for interventional stones. Adding x-ray to hydronephrosis assessment increased sensitivity in all stone categories, specifically from 39% to 68% for large stones (gain = 29%; 95%CI, 23% to 35%) and from 60% to 82% for interventional stones (gain = 22%; 95%CI, 13% to 30%). Because CT and ultrasound show strong agreement for MS-Hydro identification, physicians who depend on ultrasound-based hydronephrosis assessment could achieve similar gains by adding x-ray. CONCLUSIONS: Adding x-ray to hydronephrosis assessment substantially improves diagnostic sensitivity, enabling the detection of nearly 70% of large stones and over 80% of interventional stones. This level of sensitivity may be sufficient to reassure physicians about a renal colic diagnosis without CT imaging for many patients.

Ultra-low dose CT abdomen and pelvis for the detection of acute abdominal pathology in the emergency room: initial experience from an academic hospital.

PURPOSE: The aim of this study is to describe our initial experience using ULDCT performed in the emergency room in the evaluation of acute abdominal pathology. METHODS: Data from consecutive patients who underwent ULDCT for assessment of bowel obstruction, free intraperitoneal air, unexplained abdominal pain, or fecal loading for constipation between June 1, 2016 and March 31, 2017 was retrospectively assessed. Demographic data, radiation dose, CT findings, and clinical outcomes including performance of full dose contrast-enhanced CT (CECT), hospitalization, and surgery was collected. Concordance of ULDCT to CECT was calculated. RESULTS: ULDCT was performed in 325 patients (188 women and 137 men; mean age, 65.1 years). ULDCT detected acute abdominal pathology in 134/325 (41.2%), and in 89/134 (66.4%) it was concordant with the clinical working diagnosis. The average dose length product (DLP) was 101.6 mGy cm (range 51.7-614; median, 82.6). CECT was performed in 44/325 patients (13.5%). In 7/44 (15.9%), CECT identified discordant findings which likely impacted management. A greater proportion of patients were admitted to hospital after a positive ULDCT 99/137 (72.3%), compared to those with a negative study 81/188 (43.1%); p < 0.0001(Chi2, 27.30). Of those admitted to hospital, 11/99 (11.1%) with positive ULDCT had surgery compared to 1/81 (1.2%) with a negative ULDCT; p < 0.008 (Chi2, 6.98). CONCLUSION: With its high clinical yield and similar radiation dose, ULDCT appears as a suitable alternative to abdominal radiography for the detection of select acute abdominal pathology in the emergency room.

CT Abdominal Tomography Indications: Are We All Sticking to the Plan?

OBJECTIVE: Ultra-low radiation dose computed tomography (CT) abdominal tomography was introduced in our institution in 2016 to replace standard abdominal radiography in the investigation of emergency department patients. This project aims to ascertain whether investigation of emergency department patients using ultra-low radiation dose CT abdominal tomography complies with original indication guidelines and/or if there has been any "indication creep" 3 years after inception. METHODS: Retrospective, quality assurance project with research ethics waiver. A review of 200 consecutive patients investigated with CT abdominal tomography between February and May 2017 was performed. This was compared with 200 consecutive patients investigated between February and May 2019. Data analyzed included patient demographics, indication for scan, as well as scan and patient outcomes. RESULTS: In the 2017 group, 29/200 scans were noncompliant with approved indication guidelines. In the 2019 group, 30/200 scans were also noncompliant. There was no statistically significant difference between groups (P < .05) regarding the use of approved indications. Forty of 200 scans performed in 2017 revealed additional findings which are not specifically addressed on the reporting template. Forty-one of 200 scans in 2019 revealed these findings. CONCLUSIONS: There has been no "indication creep" for CT abdominal tomography over time.

Society of Abdominal Radiology (SAR) and European Society of Urogenital Radiology (ESUR) joint consensus statement for MR imaging of placenta accreta spectrum disorders.

OBJECTIVES: This study was conducted in order to establish the joint Society of Abdominal Radiology (SAR) and European Society of Urogenital Radiology (ESUR) guidelines on placenta accreta spectrum (PAS) disorders and propose strategies to standardize image acquisition, interpretation, and reporting for this condition with MRI. METHODS: The published evidence-based data and the opinion of experts were combined using the RAND-UCLA Appropriateness Method and formed the basis for these consensus guidelines. The responses of the experts to questions regarding the details of patient preparation, MRI protocol, image interpretation, and reporting were collected, analyzed, and classified as "recommended" versus "not recommended" (if at least 80% consensus among experts) or uncertain (if less than 80% consensus among experts). RESULTS: Consensus regarding image acquisition, interpretation, and reporting was determined using the RAND-UCLA Appropriateness Method. The use of a tailored MRI protocol and standardized report was recommended. CONCLUSIONS: A standardized imaging protocol and reporting system ensures recognition of the salient features of PAS disorders. These consensus recommendations should be used as a guide for the evaluation of PAS disorders with MRI. KEY POINTS: • MRI is a powerful adjunct to ultrasound and provides valuable information on the topography and depth of placental invasion. • Consensus statement proposed a common lexicon to allow for uniformity in MRI acquisition, interpretation, and reporting of PAS disorders. • Seven MRI features, namely intraplacental dark T2 bands, uterine/placental bulge, loss of low T2 retroplacental line, myometrial thinning/disruption, bladder wall interruption, focal exophytic placental mass, and abnormal vasculature of the placental bed, reached consensus and are categorized as "recommended" for diagnosing PAS disorders.