PURPOSE:To measure the computed tomography (CT) attenuation of acute pulmonary embolism (PE) and establish an upper Hounsfield unit (HU) threshold above which it is unlikely to occur. MATERIALS AND METHODS:This retrospective study analyzed CT pulmonary angiography (CTPA) exams in patients with acute PE (2018-2023) who had a prior negative CTPA in the preceding 2 weeks. Clot and artifact attenuation were measured on the positive and prior negative CTPA respectively. Analysis of variance with post hoc tests and linear regression analysis were performed to determine the effects of technical and other parameters on clot and artifact attenuation. RESULTS:A total of 60 patients were included, each with 1 record or a pair of CTPA exams, yielding 105 clots and 41 artifacts. Mean attenuation for acute PE was 50±40 HU, and for artifact was 110±146 HU. A threshold of 125 HU achieved 97% (102/105) sensitivity for acute PE below it and the same specificity for artifact above it. Specificity for acute PE below this threshold was 37% (15/41). Subsegmental clots had a lower attenuation than all other clots as a group. Kilovoltage peak (kVp) and proximal vessel attenuation were poor predictors of clot attenuation. CONCLUSIONS:Most acute PE demonstrated a CT attenuation ≤125 HU on standard CTPA, an upper threshold higher than previously reported, while artifacts demonstrated both lower and higher attenuation. An attenuation >125 HU on standard CTPA, favoring artifact rather than acute PE, may be a useful adjunct to morphologic differentiation between these entities.

Objective. The use of Feraheme (ferumoxytol) as a contrast agent in MR-guided focused ultrasound (MRgFUS) tumor ablations could enhance treatment safety and efficacy by improving vascular visualization through strong T1 and T2 shortening effects. However, Feraheme impact on MR thermometry and tissue heating is unclear. This study evaluates the feasibility of incorporating Feraheme into MRgFUS by assessing its impact on MR imaging contrast, MR thermometry, and thermal response in tissue-mimicking phantoms.Approach. Tissue-mimicking phantoms with 0 (baseline), 0.25, and 0.5 mM Feraheme concentrations were prepared using a validated recipe. Acoustic attenuation was measured with a commercial diagnostic ultrasound scanner. MR imaging at 1.5 T was performed to assess gradient-recalled-echo (GRE)-based thermometry signal-to-noise-ratio (SNR), relaxation rates, and relaxivities. MRgFUS system integrated with 1.5 T MRI was used to perform multiple sonications in the phantoms. Temperature elevations and focal heating areas were quantified from proton resonance frequency (PRF) shift thermometry. Experiments were repeated three times over the period of eight-weeks. Separately, temperature-dependent nuclear magnetic resonance (NMR) spectroscopy was performed at 3.0 T in saline-diluted Feraheme phantoms (0, 0.25, 0.5, and 1.0 mM) to assess the influence of Feraheme concentration on PRF coefficients used in MR thermometry.Main results. Phantoms showed nuclear relaxation times (T1: 1178.1 ± 77.8,T2: 103.21 ± 2.45 ms) and attenuation coefficients (0.34-0.36 dB cm-1MHz-1) within expected biological tissue ranges. Relaxivities demonstrated a strong linear dependence on Feraheme concentration (r1: 17.5 ± 0.2,r2: 209.2 ± 2.6 s-1mM-1). Relative to baseline (0 mM) phantom, the SNR of GRE-based thermometry increased by 12.6% at 0.25 mM and decreased by 27.1% at 0.5 mM. Sonications in Feraheme-containing phantoms resulted in statistically higher temperature elevations (p < 0.001) although no statistically significant difference was observed between 0.25 and 0.5 mM. All NMR measurements demonstrated stable, linear PRF temperature dependence (R2= 0.996-0.999), with PRF coefficients (between -0.0074 and -0.0082 ppm °C-1). The resulting thermometry bias was small and predictable (+0.67 and +1.73 per 20 °C at 3.0 T for 0.25 and 0.5 mM).Significance. These findings demonstrate that MR thermometry remains feasible at moderate Feraheme concentrations and support its potential use to enhance visualization of critical vasculature near targeted tissues during MRgFUS.

Objective: To compare left ventricular (LV) and aortic (AO) pressures obtained using fluid‐filled and high‐fidelity solid‐state pressure catheters in subjects undergoing left heart catheterization. Materials and Methods: Twenty subjects scheduled for a left heart catheterization were enrolled and 18 subjects completed this IRB‐approved study. LV and AO pressures were obtained using fluid‐filled pressure catheter (standard‐of‐care) and high‐fidelity solid‐state pressure catheter synchronously. Pressure tracings were analyzed to measure LV systolic (LVSP), LV minimum‐diastolic (LVMDP), LV end‐diastolic (LVEDP), AO systolic (AOSP), and AO diastolic (AODP) pressures. Isovolumic contraction and relaxation rates (peak ± dp/dt) were derived from the pressure waveforms. Repeated measures of variance, post hoc tests with Bonferroni corrections, and Bland–Altman plots were used for comparisons. Results: A significant main effect of the pressure catheter was noted for LVSP, LVMDP, and AOSP ( p ≤ 0.025). The LVSP and AOSP measured with fluid‐filled pressure catheters were higher by 6.6 ± 6.9 mmHg and 4.6 ± 5.2 mmHg in comparison to solid‐state pressure catheter. In contrast, the LVMDP measurements were 3.5 ± 5.7 mmHg lower than the solid‐state pressure catheter measurements. The isovolumic contraction (66.4 ± 116.0 mmHg/s) and relaxation rates (60.5 ± 113.5 mmHg/s) were not significantly different between catheter systems after Bonferroni corrections for multiple comparisons ( p ≥ 0.06). The Bland–Altman analysis revealed a bias ranging from 0.8 to 6.6 mmHg. Conclusions: Differences in LVSP, LVMDP, and AOSP were noted between the catheter systems but not for other pressure values and contraction/relaxation rates. Fluid‐filled catheters overestimated true systolic pressures in the left ventricle and aorta. Trial Registration: ClinicalTrials.gov identifier: NCT03245255

Introduction Reverse shoulder arthroplasty (RSA) is performed for various shoulder pathologies. Inadequate tensioning of the deltoid muscle can lead to complications, highlighting the need for optimization. Preoperative quantification of deltoid health may improve operative execution and outcomes. Shear wave elastography (SWE) quantifies stiffness as a marker for muscle health and tensioning. This study establishes normal reference values for the deltoid in healthy individuals. Methods 40 participants were enrolled, 10 in each 18–30, 31–40, 41–55, and 55 + age groups. Two operators performed SWE in 3 deltoid regions, and the intra- and inter-operator agreement was assessed. Results Mean values were 23.2 ± 4.6, 26.4 ± 5.6, and 17.9 ± 5.2 kPa for the anterior, lateral, and posterior regions. The posterior region did not show any age dependency. However, there were significant differences between the age groups of 18–30 and 55 + years in the anterior (19.7 ± 3.7 vs. 26.7 ± 5.3 kPa) and lateral (22.0 ± 5.4 vs. 30.2 ± 8.8 kPa). Intra-operator reliability ranged from 0.45 to 0.60, and inter-reader agreement from 0.57 to 0.85. Conclusion This study provides reference values of deltoid stiffness which could serve as a comparison with clinical measurements for RSA operative planning and execution and prediction of surgical outcomes.

Subharmonic aided pressure estimation (SHAPE) is a technique that utilizes subharmonic signals from microbubble contrast agents for pressure estimation. Validation of the SHAPE technique relies on synchronous measurements of in vivo pressures using contrast microbubbles and a pressure catheter (reference standard). For the guidance and placement of pressure catheter in vivo, iodinated contrast is used with fluoroscopy. Therefore, during data acquisition for validation studies of the SHAPE technique, both contrast microbubbles and iodinated contrast are present simultaneously within the vasculature. This study aims to elucidate the effects of iodinated contrast (Visipaque, GE HealthCare) on subharmonic signal amplitude from contrast microbubbles (Definity, Lantheus Medical Imaging, Inc.). In an acrylic water tank, 0.06 mL of Definity and varied amounts of Visipaque (0.14, 0.43, 0.85, and 1.70 mL) were added to 425 mL of deionized water. Ultrasound scanning was performed with a SonixTablet scanner (BK Medical Systems) using optimized parameters for SHAPE with Definity ( f transmit/receive = 3.0/1.5 MHz; chirp down pulse). Subharmonic data was acquired and analyzed at 9 different incident acoustic outputs ( n = 3). Results showed an increase in subharmonic signal amplitude from Definity microbubbles in the presence of 0.14 mL Visipaque by 2.8 ± 1.3 dB ( p < .001), no change with 0.85 mL Visipaque (0.7 ± 1.2 dB; p = .09) and a decrease in subharmonic amplitude in the presence of 1.70 mL Visipaque by 1.9 ± 0.7 dB ( p < .001). While statistically significant effect on subharmonic signal amplitude of Definity microbubbles was noted due to the mixture, the magnitude of the effect was minimal (~2.8 dB) and unlikely to impact in vivo SHAPE measurements.

Purpose To investigate if the right ventricular (RV) systolic and left ventricular (LV) diastolic pressures can be obtained noninvasively using the subharmonic-aided pressure estimation (SHAPE) technique with Sonazoid microbubbles. Materials and Methods Individuals scheduled for a left and/or right heart catheterization were prospectively enrolled in this institutional review board-approved clinical trial from 2017 to 2020. A standard-of-care catheterization procedure was performed by advancing fluid-filled pressure catheters into the LV and aorta (n = 25) or RV (n = 22), and solid-state high-fidelity pressure catheters into the LV and aorta in a subset of participants (n = 18). Study participants received an infusion of Sonazoid microbubbles (GE HealthCare), and SHAPE data were acquired using a validated interface developed on a SonixTablet (BK Medical) US scanner, synchronously with the pressure catheter data. A conversion factor, derived using cuff-based pressure measurements with a SphygmoCor XCEL PWA (ATCOR) and subharmonic signal from the aorta, was used to convert the subharmonic signal into pressure values. Errors between the pressure measurements obtained using the SHAPE technique and pressure catheter were compared. Results The mean errors in pressure measurements obtained with the SHAPE technique relative to those of the fluid-filled pressure catheter were 1.6 mm Hg ± 1.5 [SD] (P = .85), 8.4 mm Hg ± 6.2 (P = .04), and 7.4 mm Hg ± 5.7 (P = .09) for RV systolic, LV minimum diastolic, and LV end-diastolic pressures, respectively. Relative to the measurements with the solid-state high-fidelity pressure catheter, the mean errors in LV minimum diastolic and LV end-diastolic pressures were 7.2 mm Hg ± 4.5 and 6.8 mm Hg ± 3.3 (P ≥ .44), respectively. Conclusion These results indicate that SHAPE with Sonazoid may have the potential to provide clinically relevant RV systolic and LV diastolic pressures. Keywords: Ultrasound-Contrast, Cardiac, Aorta, Left Ventricle, Right Ventricle ClinicalTrials.gov registration no.: NCT03245255 © RSNA, 2024.

Mitochondria are double-walled organelles that generate energy in the form of ATP. ATP is an energy-rich compound and a driver of fundamental cell functions. Mitochondria-oriented studies help design advanced therapies to target lung cancer. Lung cancer is the leading cause of cancer incidences and death globally. Various studies have supported that mitochondrial function is disrupting cancerous cells. Mitochondrial dysfunctions lead to dysregulated ATP synthesis, disturbed respiratory chain, unbalanced mitochondrial fission or fusion, disturbed cellular redox homeostasis, dysregulated apoptosis, and interfered non-smooth intracellular calcium signaling. Dysfunction mitochondria are associated with cancer cell proliferation, metastasis, and death. In this review, we have tried to elaborate on how normal cell mitochondria function differently from the mitochondria of lung cancer cells. It includes various targets such as mitochondrial proteins and related pathways, along with new drug molecules like Militarin analog-1, Dihydromyricetin, and papuamine. As mitochondrial metabolism is associated with the proliferation and metastasis of lung cancer cells, finding interlinks between malfunctioning mitochondria and the process of lung cancer can promote the development of new treatments.

Introduction: Dexmedetomidine is among several pharmacological agents used for the treatment of shivering. Dexmedetomidine is a highly selective α2-adrenoceptor agonist with potent effects on the central nervous system without respiratory depression and it also has several desirable properties like sedation, anxiolysis, sympatholysis and analgesia. To evaluate Objectives: the effect of intrathecal Dexmedetomidine on - reducing incidence of post spinal shivering, reducing intensity of shivering, haemodynamic parameters, occurrence of complications. A prospective, randomized double blind manner Material & Methods: to study the efcacy dexmedetomidine in the prevention of shivering including 60 patients undergoing cesarean section were included. Two groups were divided. Group D received intrathecal Inj. Bupivacaine 0.5% heavy (2 ml) + Inj. dexmedetomidine 5 g and Group C received intrathecal Inj. Bupivacaine 0.5% heavy (2 ml) + Inj. normal saline 0.05 ml. Both groups observed for occurrence of shivering and severity of shivering according bedside shivering assessment scale. Dexmedetomidine was found to be effective i Results : n the prevention of shivering and reducing it's severity as only 4 patient had grade 1 and only 1 patient had grade 2 shivering among the 30 patients who were given dexmedetomidine compared to control group in which 9 patient had grade 1 and 8 patients had grade 2 shivering. It is concluded Conclusion : that adding 5 g dexmedetomidine to heavy bupivacaine (0.5%) in spinal anaesthesia can decreases the incidence and intensity of shivering without occurrence of signicant adverse effect in patient undergoing cesarean section.

Background and Aims:Distinguishing alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) with biopsy alone is often difficult without a reliable clinical context. A novel finding on liver imaging, perivascular branching heterogeneity, has shown promise in distinguishing between these chronic liver diseases. Our study investigated the role of this finding on imaging to differentiate between ASH and NASH. The aim of this study was to determine the utility and reproducibility of this novel radiographic marker to help distinguish ASH from NASH.Methods:This was a retrospective cohort study conducted between 2016 and 2020 in patients with both liver biopsy-confirmed steatohepatitis/chronic hepatitis and abdominal magnetic resonance imaging within 13 months of each other. Two radiologists, blinded to patient clinical history and diagnosis, categorized the appearance of the liver as: 1- homogeneity, 2- mild heterogeneity, 3- moderate heterogeneity, 4- possible perivascular branching, 5- definite perivascular branching.Results:Of the 90 patients in the study, 60 were identified as NASH and 30 as ASH. The area under the curve (AUC) for both reader 1 and 2 when using the 5-point scale was 0.69 (CI: 0.56-0.82, p=0.006) and 0.72 (CI: 0.60-0.85, p=0.001), respectively. The positive predictive value (PPV) for identification of ASH when scoring 5 was 64.7% and 66.7% for reader 1 and 2, respectively. Interclass correlation coefficient was 0.74 in patients with ASH, indicating moderate reliability among both readers.Conclusions:Identification of this perivascular branching pattern on imaging is a promising novel diagnostic marker that can be used with other methods to help distinguish between ASH and NASH.

Detection of pulmonary nodules on chest x-rays is an important task for radiologists. Previous studies have shown improved detection rates using gray-scale inversion. The purpose of our study was to compare the efficacy of gray-scale inversion in improving the detection of pulmonary nodules on chest x-rays for radiologists and machine learning models (ML). We created a mixed dataset consisting of 60, 2-view (posteroanterior view - PA and lateral view) chest x-rays with computed tomography confirmed nodule(s) and 62 normal chest x-rays. Twenty percent of the cases were separated for a testing dataset (24 total images). Data augmentation through mirroring and transfer learning was used for the remaining cases (784 total images) for supervised training of 4 ML models (grayscale PA, grayscale lateral, gray-scale inversion PA, and gray-scale inversion lateral) on Google's cloud-based AutoML platform. Three cardiothoracic radiologists analyzed the complete 2-view dataset (n=120) and, for comparison to the ML, the single-view testing subsets (12 images each). Gray-scale inversion (area under the curve (AUC) 0.80, 95% confidence interval (CI) 0.75-0.85) did not improve diagnostic performance for radiologists compared to grayscale (AUC 0.84, 95% CI 0.79-0.88). Gray-scale inversion also did not improve diagnostic performance for the ML. The ML did demonstrate higher sensitivity and negative predictive value for grayscale PA (72.7% and 75.0%), grayscale lateral (63.6% and 66.6%), and gray-scale inversion lateral views (72.7% and 76.9%), comparing favorably to the radiologists (63.9% and 72.3%, 27.8% and 58.3%, 19.5% and 50.5% respectively). In the limited testing dataset, the ML did demonstrate higher sensitivity and negative predictive value for grayscale PA (72.7% and 75.0%), grayscale lateral (63.6% and 66.6%), and gray-scale inversion lateral views (72.7% and 76.9%), comparing favorably to the radiologists (63.9% and 72.3%, 27.8% and 58.3%, 19.5% and 50.5%, respectively). Further investigation of other post-processing algorithms to improve diagnostic performance of ML is warranted.

Reject rate analysis is considered an integral part of a diagnostic radiography quality control (QC) program. A rejected image is a patient radiograph that was not presented to a radiologist for diagnosis and that contributes unnecessary radiation dose to the patient. Reject rates that are either too high or too low may suggest systemic department shortcomings in QC mechanisms. Due to the lack of standardization, reject data often cannot be easily compared between radiography systems from different vendors. The purpose of this report is to provide guidance to help standardize data elements that are required for comprehensive reject analysis and to propose data reporting and workflows to enable an effective and comprehensive reject rate monitoring program. Essential data elements, a proposed schema for classifying reject reasons, and workflow implementation options are recommended in this task group report.

BACKGROUND Noninvasive and accurate assessment of intracardiac pressures has remained an elusive goal of noninvasive cardiac imaging. OBJECTIVES The purpose of this study was to investigate if errors in intracardiac pressures obtained noninvasively using contrast microbubbles and the subharmonic-aided pressure estimation (SHAPE) technique are < 5 mm Hg. METHODS In a nonrandomized institutional review board-approved clinical trial (NCT03243942), patients scheduled for a left-sided and/or right-sided heart catheterization procedure and providing written informed consent were included. A standard-of-care catheterization procedure was performed advancing clinically used pressure catheters into the left and/or right ventricles and/or the aorta. After pressure catheter placement, patients received an infusion of Definity microbubbles (n = 56; 2 vials diluted in 50 mL of saline; infusion rate: 4-10 mL/min) (Lantheus Medical Imaging). Then SHAPE data was acquired using a validated interface developed on a SonixTablet scanner (BK Medical Systems) synchronously with the pressure catheter data. A conversion factor (mm Hg/dB) was derived from SHAPE data and measurements with a SphygmoCor XCEL PWA device (ATCOR Medical) and was combined with SHAPE data from the left and/or the right ventricles to obtain clinically relevant systolic and diastolic ventricular pressures. RESULTS The mean value of absolute errors for left ventricular minimum and end diastolic pressures were 2.9 +/- 2.0 and 1.7 +/- 1.2 mm Hg (n =26), respectively, and for right ventricular systolic pressures was 2.2 +/- 1.5 mm Hg (n = 11). Two adverse events occurred during Definity infusion; both were resolved. CONCLUSIONS These results indicate that the SHAPE technique with Definity microbubbles is encouragingly efficacious for obtaining intracardiac pressures noninvasively and accurately. (Noninvasive, Subharmonic Intra-Cardiac Pressure NCT03243942) (J Am Coll Cardiol Img 2023;16:224-235) (c) 2023 by the American College of Cardiology Foundation.

Purpose: To compare left-ventricular and aortic pressures obtained using fluid-filled and high-fidelity solid-state pressure catheters in subjects undergoing left heart catheterization. Methods: Twenty subjects scheduled for a left heart catheterization were enrolled and 18 subjects completed this IRB-approved study. During catheterization, left-ventricular (LV) and aortic (AO) pressures were obtained using a fluid-filled pressure catheter (standard-of-care) and a high-fidelity solid-state pressure catheter synchronously. The pressure tracings were analyzed by two independent readers to measure LV systolic (LVSP), LV minimum diastolic (LVMDP), LV end diastolic (LVEDP), AO systolic (AOSP), and AO diastolic (AODP) pressures. Derivatives of the pressure waveforms were computed to estimate the isovolumic contraction and relaxation rates (peak ± dp/dt). The measurements were made over multiple cardiac cycles and averaged results were used for comparisons using repeated measures analysis of variance, post-hoc tests with Bonferroni corrections and Bland-Altman plots. Results: A significant main effect of the pressure catheter was noted for LVSP, LVMDP and AOSP (p < 0.025). The LVSP and AOSP measured with fluid-filled pressure catheters were higher by 6.6 ± 6.9 mmHg and 4.6 ± 5.2 mmHg in comparison to the high-fidelity solid-state pressure catheter assessments. In contrast, the LVMDP measurements were 3.5 ± 5.7 mmHg lower than the solid-state pressure catheter measurements. When evaluating the differences between readers, the maximum difference was noted for LVEDP measurements (3.1 ± 2.4 mmHg; p ≤ 0.001). The differences in isovolumic contraction rate (66.4 ± 116.0 mmHg/s) and relaxation rate (60.5 ± 113.5 mmHg/s) were not significantly different between the two catheter systems after Bonferroni corrections for multiple comparisons (p > 0.06). Bland-Altman analysis revealed a bias ranging from 0.8 to 6.6 mmHg for all the pressure measurements. Conclusions: There are differences in LVSP, LVMDP, and AOSP measured using fluid-filled and high-fidelity solid-state pressure catheters. Clinicians should be aware that the fluid-filled catheters commonly overestimate the true systolic pressures in the left ventricle and aorta.

Purpose: To investigate if clinical non-contrast chest CT studies obtained with PCD CT using much lower radiation exposure can achieve the same image quality as with the currently established EID protocol.Materials/methods: A total of seventy-one patients were identified who had a non-contrast chest computed tomography (CT) done on PCD CT and EID CT scanners within a 4-month interval. Five fellowship trained chest radiologists, blinded to the scanner details were asked to review the cases side-by-side and record their preference for images from either the photon-counting-detector (PCD) CT or the energy-integrating detector (EID) CT scanner.Results: The median CTDIvol for PCD-CT system was 4.710 mGy and EID system was 7.80 mGy (p < 0.001). The median DLP with the PCD-CT was 182.0 mGy.cm and EID system was 262.60 mGy.cm (p < 0.001). The contrast to noise ratio (CNR) was superior on the PCD-CT system 59.2 compared to the EID-CT 53.3; (p < 0.001). Kappa statistic showed that there was poor agreement between the readers over the image quality from the PCD and EID scanners (kappa = 0.19; 95 % CI: 0.12 - 0.27; p < 0.001). Chi-square analysis revealed that 3 out of 5 readers showed a significant preference for images from the PCDCT (p <= 0.012). There was no significant difference in the preferences of two readers between EID-CT and PCD-CT images.Conclusion: The first clinical PCD-CT system allows a significant reduction in radiation exposure while maintaining image quality and image noise using a standardized non-contrast chest CT protocol.

There is no current authoritative accounting of the number of clinical imaging physicists practicing in the United States. Information about the workforce is needed to inform future efforts to secure training pathways and opportunities. In this study, the AAPM Diagnostic Demand and Supply Projection Working Group collected lists of medical physicists from several state registration and licensure programs and the Conference of Radiation Control Program Directors (CRCPD) registry. By cross-referencing individuals among these lists, we were able to estimate the current imaging physics workforce in the United States by extrapolating based on population. The imaging physics workforce in the United States in 2019 consisted of approximately 1794 physicists supporting diagnostic X-ray (1073 board-certified) and 934 physicists supporting nuclear medicine (460 board-certified), with a number of individuals practicing in both subfields. There were an estimated 235 physicists supporting nuclear medicine exclusively (150 board-certified). The estimated total workforce, accounting for overlap, was 2029 medical physicists. These estimates are in approximate agreement with other published studies of segments of the workforce.

1 Department of Radiology, The Metro Health System, Cleveland, Ohio, USA 2 Department of Radiology, College of Medicine, University of Kentucky, Lexington, Kentucky, USA 3 Department of Radiology, Maine Medical Center, Portland, Maine, USA 4 Clinical Dose Optimization Service, LANDAUER Medical Physics, Glenwood, Illinois, USA 5 Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA 6 Department of Diagnostic Radiology, Oregon Health & Science University, Portland, Oregon, USA 7 Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA 8 Department of Radiation Physics & Safety, Atlantic Medical System Morristown, Morristown, New Jersey, USA 9 Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA 10 RJK Medical Physics, Inc., Cleveland, Ohio, USA 11 Clinical Dose Optimization ServiceTM/OPTIMIZETM Division, LANDAUER Medical Physics, Glenwood, Illinois, USA 12 Upstate Medical Physics, P.C., Victor, New York, USA 13 Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, USA 14 Mayo Clinic, Department of Radiology, Rochester, Minnesota, USA 15 Department of Radiology, University of Florida, Gainesville, Florida, USA 16 KLS Physics Group, LLC, Ruston, Louisiana, USA 17 Cleveland Clinic, Department of Radiology, Cleveland, Ohio, USA

BACKGROUND This study compared aortic pressures estimated using a SphygmoCor XCEL PWA device (ATCOR, Naperville, IL) noninvasively with aortic pressures obtained using pressure catheters during catheterization procedures and analyzed the impact of a linear-fit function on the estimated pressure values. METHODS One hundred and thirty-six patients scheduled for cardiac catheterization procedure were enrolled in IRB approved studies. Catheterization procedures were performed according to standard-of-care to acquire aortic pressure measurements. Immediately after the catheterization procedure with the pressure catheters removed, while the patients were still in the catheterization laboratory, central aortic pressures were estimated with the SphygmoCor device (using its inbuilt transfer function). The error between measured and estimated aortic pressures was evaluated using Bland-Altman analysis (n = 93). A linear-fit was performed between the measured and estimated pressures, and using the linear equation the error measurements were repeated. A bootstrap analysis was performed to test the generalizability of the linear-fit function. In a subset of cases (n = 13), central aortic pressure values were also obtained using solid-state high-fidelity catheters (Millar, Houston, TX), and the error measurements were repeated. RESULTS The magnitude of errors between the measured and estimated aortic pressures (mean errors >6.4 mm Hg; mean errors >8.0 mm Hg in the subset) were reduced to less than 1 mm Hg after using the linear-fit function derived in this study. CONCLUSIONS For the population examined in this study, the SphygmoCor data must be used with the linear-fit function to obtain aortic pressures that are comparable to the measurements obtained using pressure catheters.

OBJECTIVES:Subharmonic aided pressure estimation (SHAPE) has been shown effective for noninvasively measuring hydrostatic fluid pressures in a variety of clinical applications. The objective of this study was to explore potential improvements in SHAPE sensitivity using monodisperse microbubbles.METHODS:Populations of monodisperse microbubbles were created using a commercially available microfluidics device (Solstice Pharmaceuticals). Size distributions were assessed using a Coulter Counter and stability of the distribution following fabrication was evaluated over 24 hours. Attenuation of the microbubble populations from 1 to 10 MHz was then quantified using single element transducers to identify each formulation's resonance frequency. Frequency spectra over increasing driving amplitudes were investigated to determine the nonlinear phases of subharmonic signal generation. SHAPE sensitivity was evaluated in a hydrostatic pressure-controlled water bath using a Logiq E10 scanner (GE Healthcare).RESULTS:Monodisperse lipid microbubble suspensions ranging from 2.4 to 5.3 μm in diameter were successfully created and they showed no discernable change in size distribution over 24 hours following activation. Calculated resonance frequencies ranged from 2.1 to 6.3 MHz and showed excellent correlation with microbubble diameter (R2  > 0.99). When investigating microbubble frequency response, subharmonic signal occurrence was shown to begin at 150 kPa peak negative pressure, grow up to 225 kPa, and saturate at approximately 250 kPa. Using the Logiq E10, monodisperse bubbles demonstrated a SHAPE sensitivity of -0.17 dB/mmHg, which was nearly twice the sensitivity of the commercial polydisperse microbubble currently being used in clinical trials.CONCLUSIONS:Monodisperse microbubbles have the potential to greatly improve the sensitivity of SHAPE for the noninvasive measurement of hydrostatic pressures.

To evaluate the productivity difference between teaching and non-teaching workflow models in an abdominal imaging division in an academic radiology department. RVU data were compiled for six faculty members from the abdominal imaging division over a six-month period. Modalities included ultrasound and CT of the abdomen and pelvis. The relative RVU productivity for faculty members by workflow was compared individually and the composite data for the workflow models were compared. The relative RVU productivity for each faculty member was compared individually and in aggregate to study the effect of the workflow models on RVUs using factorial ANOVA. Turnaround times (TAT) were compared for each attending under both models. TAT data were analyzed using paired t-tests with Bonferroni corrections for multiple comparisons. Daily RVU data from 387 instances were analyzed. Daily RVUs for faculty members ranged from 23.5 ± 2.3 (mean ± standard error) to 46.2 ± 2.4 with non-teaching and from 29.8 ± 2.2 to 54.4 ± 2.7 with teaching workflow, respectively. There was a significant main effect of the workflow model on RVU productivity (p < 0.05). A significant increase of 27.8% in RVUs was noted with teaching workflow (42.8 ± 0.9) relative to non-teaching workflow (33.5 ± 1.7; p < 0.05). Teaching workflow resulted in significantly higher view-final and complete-final TATs (593 ± 112 min, mean ± SE and 841 ± 96 min, mean ± SE, respectively) compared to the non-teaching workflow (385 ± 124 min). Teaching workflow improves abdominal imaging productivity with an increase in report turnaround times.