Diagnostic performance and feasibility of dual-layer detector dual-energy CT for characterization of urinary stones in patients of different sizes.

BACKGROUND: Urinary stones are frequently encountered in urology and are typically identified using non-contrast CT scans. Dual-energy CT (DECT) is a valuable imaging technique that produces material-specific images and allows for precise assessment of stone composition by estimating the effective atomic number (Zeff), a capability not achievable with the conventional single-energy CT's attenuation measurement method. PURPOSE: To investigate the diagnostic performance and image quality of dual-layer detector DECT (dlDECT) in characterizing urinary stones in patients of different sizes. METHODS: All consecutive dlDECT examinations with stone protocol and presence of urinary stones between July 2018 and November 2019 were retrospectively evaluated. Two radiologists independently reviewed 120 kVp and color-overlay Zeff images to determine stone composition (reference standard = crystallography) and image quality. The objective analysis included image noise and Zeff values measurement. RESULTS: A total of 739 urinary stones (median size 3.7 mm, range 1-35 mm) were identified on 177 CT examinations from 155 adults (mean age, 57 ± 15 years, 80 men, median weight 82.6 kg, range 42.6-186.9 kg). Using color-overlay Zeff images, the radiologists could subjectively interpret the composition in all stones ≥ 3 mm (n = 491). For stones with available reference standards (n = 74), dlDECT yielded a sensitivity of 80% (95%CI 44-98%) and a specificity of 98% (95%CI 92-100%) in visually discriminating uric acid from non-uric acid stones. Patients weighing > 90 kg and ≤ 90 kg had similar stone characterizability (p = 0.20), with 86% of stones characterized in the > 90 kg group and 87% in the ≤ 90 kg group. All examinations throughout various patients' weights revealed acceptable image quality. A Zeff cutoff of 7.66 accurately distinguished uric acid from non-uric acid stones (AUC = 1.00). Zeff analysis revealed AUCs of 0.78 and 0.91 for differentiating calcium-based stones from other non-uric stones and all stone types, respectively. CONCLUSION: dlDECT allowed accurate differentiation of uric acid and non-uric acid stones among patients with different body sizes with acceptable image quality. CLINICAL IMPACT: The ability to accurately differentiate uric acid stones from non-uric acid stones using color-overlay Zeff images allows for better tailored treatment strategies, helping to choose appropriate interventions and prevent potential complications related to urinary stones in patient care.

Point-of-Care Synchronous Virtual Radiology Consultations for Atherosclerotic Disease in Primary Care: A Cluster-Randomized Study.

PURPOSE: Synchronous virtual visits are an emerging model of care, and their feasibility has been demonstrated in radiology. The purpose of this study was to assess the value of point-of-care virtual radiology primary care consultations for atherosclerotic vascular disease management. METHODS: In this institutional review board-approved study, 107 age- and gender-matched patients were assigned to control (n = 62) and intervention (n = 45) arms with the following inclusion criteria: (1) age > 45 years, (2) consult with a primary care physician (PCP), and (3) recent CT of the chest or abdomen demonstrating atherosclerotic calcification. In the intervention arm, virtual real-time radiology consultation with referring PCPs and patients was conducted, with review of CT images focused on the extent of vascular atherosclerosis. Patients in the control arm followed the current standard of care of PCPs' discussing relevant imaging results, if any. RESULTS: Thirty-one patients in the intervention arm and 31 patients in the control arm completed the study (control: 64.5% women; mean age, 68 years; intervention: 67.7% women; mean age, 67 years). Discussion of imaging findings occurred with all patients in the intervention arm (discussion with PCP and virtual consultation with radiologist) and with 45% of patients in the control arm (PCP only; P < .001). All patients in the intervention arm indicated that seeing or discussing their images improved their understanding of their disease, compared with 85% of patients in the control arm (P = .04). In the intervention arm, 10 of 31 patients (32.2%) left the visit with changes in prescriptions for statins or antihypertensive medications, compared with only 4 of 31 patients (13%) in the control arm (P = .04). CONCLUSIONS: Point-of-care radiology virtual visits enhance patient understanding and may influence the longitudinal management of atherosclerotic disease in primary care.

Point-of-Care Virtual Radiology Consultations in Primary Care: A Feasibility Study of a New Model for Patient-Centered Care in Radiology.

BACKGROUND: The goal of this study is to assess the value of point-of-care virtual consultations in radiology. METHODS: We conducted an institutional review board-approved feasibility study of video-based radiology consultations in an internal medicine primary care clinic at a quaternary academic medical center. The study included 3 primary care providers (PCPs) and enrolled 43 patients. Inclusion criteria consisted of the following: age > 18 years, English speaking, recent radiology examination at our institution, and patient consenting to participate. Patients completed a pre- and postvisit survey. PCPs completed a postvisit survey. Primary study end points included the effect on patient and provider satisfaction, effect on patient experience and understanding of medical condition, and impact on PCP's management decisions. Statistical significance was assessed using Fisher's exact test. RESULTS: Of the enrolled patients, 93% (n = 40 of 43) indicated that they were satisfied with the virtual consultation visit. The PCPs were satisfied with the virtual consultation in 97% of consultations (n = 42 of 43). In addition, 88% (n = 38 of 43) of patients indicated improved understanding of their medical condition as a result of the virtual consultation, and 91% of patients (n = 39 of 43) were interested in similar consultations in the future. The participating PCPs indicated that the consultation was helpful in their management decisions in 83% of visits. Patient's interest in receiving their imaging results from radiologist increased from 56% to 88% when comparing pre- and post-virtual consultation survey results (P = .03). CONCLUSION: Initial experience with virtual radiology consultations show high rates of patient and provider satisfaction. Virtual radiology consultations have the potential to advance radiology's value in care delivery.

Dual-layer dual-energy CT for characterization of adrenal nodules: can virtual unenhanced images replace true unenhanced acquisitions?

PURPOSE: To investigate the diagnostic performance of dual-layer dual-energy CT (dlDECT) in the evaluation of adrenal nodules. METHODS: In this retrospective study, 66 patients with triphasic dlDECT (unenhanced, venous phase (VP), delayed phase (DP)) for suspected adrenal lesions were included. Virtual unenhanced images (VUE) were derived from VP acquisitions. Reference diagnoses were established with true unenhanced (TUE) attenuation, absolute washout, follow-up imaging and pathological data. Attenuation for adrenal lesions and abdominal tissues was acquired on TUE, VUE, VP and DP images. VUE and TUE attenuation were compared in all included tissues. Characterization of adrenal nodules based on TUE and VUE attenuation was investigated. ROC analysis was used to determine an adjusted threshold for diagnosing lipid-rich adenomas. RESULTS: Seventy-three adrenal nodules (mean size: 18.9 ± 8.9 mm) were identified in 66 patients (38 females, 28 males; age: 61 ± 13 years) including adenoma (n = 65), metastases (n = 2), pheochromocytoma (n = 3), adrenocortical carcinoma (n = 1) and myelolipoma (n = 2). Mean attenuation of all included tissues except for the abdominal aorta (p = 0.11) was significantly higher in VUE compared to TUE images, including the attenuation of adrenal nodules (20.0 ± 17.2 vs. 7.1 ± 19.8; p < 0.05). Classification of adrenal adenomas as lipid-rich based on VUE attenuation ≤ 10 HU yielded a sensitivity/specificity of 0.2/1.0, while an adjusted threshold of ≤ 22 HU yielded a sensitivity/specificity of 0.82/0.85. CONCLUSION: dlDECT-derived VUE images overestimated attenuation in adrenal nodules, resulting in low sensitivity for diagnosis of lipid-rich adenomas using the established 10 HU threshold. Based on an adjusted threshold (≤ 22 HU) a higher sensitivity was attained, yet at the expense of a lower specificity, warranting further validation.

Low keV portal venous phase as a surrogate for pancreatic phase in a pancreatic protocol dual-energy CT: feasibility, image quality, and lesion conspicuity.

OBJECTIVE: To assess the feasibility of a proposed pancreatic protocol CT generated from portal-venous phase (PVP) dual-energy CT (DECT) acquisition and its impact on image quality, lesion conspicuity, and arterial visualization/involvement. METHODS: We included 111 patients (mean age, 66.8 years) who underwent pancreatic protocol DECT (pancreatic phase, PP, and PVP). The original DECT acquisition was used to create two data sets-standard protocol (50 keV PP/65 keV PVP) and proposed protocol (40 keV/65 keV PVP). Three reviewers evaluated the two data sets for image quality, lesion conspicuity, and arterial visualization/involvement using a 5-point scale. The signal-to-noise ratio (SNR) of pancreas and lesion-to-pancreas contrast-to-noise ratio (CNR) was calculated. Qualitative scores, quantitative parameters, and dose-length product (DLP) were compared between standard and proposed protocols. RESULTS: The image quality, SNR of pancreas, and lesion-to-pancreas CNR of the standard and proposed protocol were comparable (p = 0.11-1.00). Lesion conspicuity was comparable between the standard and proposed protocols for pancreatic ductal adenocarcinoma (p = 0.55) and pancreatic cysts (p = 0.28). The visualization of larger arteries and arterial involvement were comparable between the two protocols (p = 0.056-1.00) while the scores were higher for smaller vessels in the standard protocol (p < 0.0001-0.0015). DLP of the proposed protocol (670.4 mGy·cm) showed a projected 42% reduction than the standard protocol (1145.9 mGy·cm) (p < 0.0001). CONCLUSION: Pancreatic protocol CT generated from a single PVP DECT acquisition is feasible and could potentially be an alternative to the standard pancreatic protocol with PP and PVP. KEY POINTS: • The lesion conspicuity for focal pancreatic lesions was comparable between the proposed protocol and standard dual-phase pancreatic protocol CT. • Qualitative and quantitative image assessments were almost comparable between two protocols. • The radiation dose of a proposed protocol showed a projected 42% reduction from the conventional protocol.

Computed tomography findings of metabolic syndrome in patients with acute colonic diverticulitis.

INTRODUCTION: Many factors associated with colonic diverticulitis are also part of the clinical definition of the metabolic syndrome. Computed tomography (CT) is commonly performed in symptomatic patients, such as those with suspected or known acute diverticulitis, and could add additional value for the health of these patients by identifying and reporting CT biomarkers of metabolic syndrome, if present and detectable. The purpose of this study was to identify CT biomarkers of metabolic syndrome in patients with acute colonic diverticulitis. METHODS: We retrospectively reviewed 243 patients (mean-60 yrs, M:F:126:117) diagnosed with colonic diverticulitis on CT between March 2015 and March 2017 for hepatic steatosis, vascular calcifications, abdominal diameters and fat volumes. Criteria of metabolic syndrome were obtained from medical records. Differences in imaging biomarkers were compared using chi-square comparisons stratified by metabolic syndrome, abdominal diameter and fat volume. RESULTS: Of 243 patients, 33% demonstrated hepatic steatosis and 71% atherosclerotic vascular calcifications on CT. 28% met criteria for metabolic syndrome. Patients with metabolic syndrome had higher occurrence of hepatic steatosis, sagittal diameter ≥ 35 cm, visceral fat > 5000 cm3 and subcutaneous fat > 8300 cm3 (P < 0.05), but not vascular calcifications (P > 0.05). CONCLUSIONS: CT biomarkers of metabolic syndrome are commonly encountered in patients with acute diverticulitis. Recognizing and reporting these findings can guide towards further evaluation for metabolic syndrome.

Rapid kVp-switching DECT portal venous phase abdominal CT scans in patients with large body habitus: image quality considerations.

PURPOSE: To assess the diagnostic image quality and material decomposition characteristics of portal venous phase abdominal CT scans performed on rapid kVp-switching DECT (rsDECT) in patients with large body habitus. METHODS: We retrospectively included consecutive patients with large body habitus (≥ 90 kg) undergoing portal venous phase abdominal CT scans on rsDECT scanners between Sep 2014 and March 2018. Qualitative and quantitative assessment of the DECT data sets [65 keV monoenergetic, material density iodine (MD-I) and material density water (MD-W) images] was performed for determination of image quality (IQ) and image noise. Correlation of qualitative assessment scores with weight, BMI and patients' diameter were calculated using Pearson correlation test. Optimal thresholds were calculated using AUC and Youden index to define most appropriate size cut off, below which the IQ of material density images is largely acceptable. RESULTS: The 65 keV monoenergetic images were of diagnostic quality (diagnostic acceptability, DA ≥ 3) in 97.8% of patients (n = 91/93). However, there was significant IQ degradation of MD-I images in 20.4% (n = 19/93, DA < 3) of patients. Similarly, there was significant degradation (DA < 3) of MD-W images in 26.9% (25/92). Clinically significant artifacts (PA ≥ 3/4) were seen in 31% (n = 29/93) and 32.3% (30/93) of MD-I and MD-W images respectively. Optimal threshold for diagnostic acceptability of MD-I images were 110 kg for weight and 33.5 kg/m2 for BMI. CONCLUSION: Rapid kVp-switching DECT provides diagnostically acceptable monoenergetic images for patients with large body habitus (≥ 90 kg). There is degradation of IQ in the material density specific images particularly in patients weighing > 110 kg and with BMI > 33.5 kg/m2, due to higher number of artifacts.