Frailty assessment prior to thoracic surgery for lung or esophageal cancer: a feasibility study.

BACKGROUND: Frailty assessment has not been thoroughly assessed in thoracic surgery. Our primary objective was to assess the feasibility of comprehensive frailty testing prior to lung and esophageal surgery for cancer. The secondary objective was to assess the utility of frailty indices in risk assessment prior to thoracic surgery. METHODS: Prospectively recruited patients completed multiple physiotherapy tests (6-min walk, gait speed, hand-grip strength), risk stratification (Charlson Comorbidity Index, Revised Cardiac Risk Index, Modified Frailty Index), and quality of life questionnaires. Lean psoas area was also assessed by a radiologist using positron emission tomography/computed tomography scans. Data was analyzed using Fisher's exact, Mann-Whitney U and independent t tests. RESULTS: The feasibility of comprehensive frailty assessment was assessed over a 4-month period among 40 patients (esophagus n = 20; lung n = 20). Risk stratification questionnaires administered in clinic had 100% completion rates. Physiotherapy testing required a trained physiotherapist and an additional visit to the pre-admission clinic; these tests proved difficult to coordinate and had lower completion rates (63-75%). Although most measures were not significantly associated with occurrence of complications, the Modified Frailty Index approached statistical significance (p = 0.06). CONCLUSIONS: Frailty assessment is feasible in the pre-operative outpatient setting and had a high degree of acceptance among surgeons and patients. Of the risk stratification questionnaires, the Modified Frailty Index may be useful in predicting outcomes as per this feasibility study. Pre-operative frailty assessment can identify vulnerable oncology patients to aid in treatment planning with the goal of optimizing clinical outcomes and resource allocation.

Increase in Utilization of Afterhours Medical Imaging: A Study of Three Canadian Academic Centers.

OBJECTIVES: The objectives of our study were to assess trends in afterhours medical imaging utilization for emergency department (ED) and inpatient (IP) patient populations from 2006-2013, including analysis by modality and specialty and with adjustment for patient volume. METHODS: For this retrospective study, we reviewed the number of CT, MRI, and ultrasound studies performed for the ED and IP patients during the afterhours time period (5pm - 8am on weekdays and 24 hours on weekends and statutory holidays) from 2006-2013 at three different Canadian academic hospitals. We used the Jonckheere-Terpstra (JT) test to determine statistical significance of imaging and patient volume trends. A regression model was used to examine whether there was an increasing trend over time in the volume of imaging tests per 1000 patients. RESULTS: For all three sites from 2006-2013 during the afterhours time period: There was a statistically significant increasing trend in total medical imaging volume, which also held true when the volumes were assessed by modality and by specialty. There was a statistically significant increasing trend in ED and IP patient volume. When medical imaging volumes were adjusted for patient volumes, there was a statistically significant increasing trend in imaging being performed per patient. CONCLUSION: Afterhours medical imaging volumes demonstrated a statistically significant increasing trend at all three sites from 2006-2013 when assessed by total volume, modality, and specialty. During the same time period and at all three sites, the ED and IP patient volumes also demonstrated a statistically significant increasing trend with more medical imaging, however, being performed per patient.

Assessment of feasibility of running RSNA's MIRC on a Raspberry Pi: a cost-effective solution for teaching files in radiology.

PURPOSE: The value of a teaching case repository in radiology training programs is immense. The allocation of resources for putting one together is a complex issue, given the factors that have to be coordinated: hardware, software, infrastructure, administration, and ethics. Costs may be significant and cost-effective solutions are desirable. METHODS: We chose Medical Imaging Resource Center (MIRC) to build our teaching file. It is offered by RSNA for free. For the hardware, we chose the Raspberry Pi, developed by the Raspberry Foundation: a small control board developed as a low cost computer for schools also used in alternative projects such as robotics and environmental data collection. Its performance and reliability as a file server were unknown to us. For the operational system, we chose Raspbian, a variant of Debian Linux, along with Apache (web server), MySql (database server) and PHP, which enhance the functionality of the server. A USB hub and an external hard drive completed the setup. Installation of software was smooth. RESULTS: The Raspberry Pi was able to handle very well the task of hosting the teaching file repository for our division. Uptime was logged at 100 %, and loading times were similar to other MIRC sites available online. We setup two servers (one for backup), each costing just below $200.00 including external storage and USB hub. CONCLUSION: It is feasible to run RSNA's MIRC off a low-cost control board (Raspberry Pi). Performance and reliability are comparable to full-size servers for the intended purpose of hosting a teaching file within an intranet environment.

Hybrid iterative reconstruction technique for abdominal CT protocols in obese patients: assessment of image quality, radiation dose, and low-contrast detectability in a phantom.

OBJECTIVE: The purpose of this study was to assess the impact of a noise reduction technique on image quality, radiation dose, and low-contrast detectability in abdominal CT for obese patients. MATERIALS AND METHODS: A liver phantom with 12 different tumors was designed, and fat rings were added to mimic intermediately sized and large patients. The intermediate and large phantoms were scanned with our standard abdominal CT protocol (image noise level of 15 HU and filtered back projection [FBP]). The large phantom was scanned with five different noise levels (10, 12.5, 15, 17.5, and 20 HU). All datasets for the large phantom were reconstructed with FBP and the noise reduction technique. The image noise and the contrast-to-noise ratio (CNR) were assessed. Tumor detection was independently performed by three radiologists in a blinded fashion. RESULTS: The application of the noise reduction method to the large phantom decreased the measured image noise (range, -14.5% to -37.0%) and increased the CNR (range, 26.7-70.6%) compared with FBP at the same noise level (p < 0.001). However, noise reduction was unable to improve the sensitivity for tumor detection in the large phantom compared with FBP at the same noise level (p > 0.05). Applying a noise level of 15 HU, the overall sensitivity for tumor detection in the intermediate and large phantoms with FBP measured 75.5% and 87.7% and the radiation doses measured 42.0 and 23.7 mGy, respectively. CONCLUSION: Although noise reduction significantly improved the quantitative image quality in simulated large patients undergoing abdominal CT compared with FBP, no improvement was observed for low-contrast detectability.

Assessment of trabecular bone structure using MDCT: comparison of 64- and 320-slice CT using HR-pQCT as the reference standard.

OBJECTIVES: The aim of our study was to perform trabecular bone structure analysis with images from 64- and 320-slice multidetector computed tomography (MDCT) and to compare these with high-resolution peripheral computed tomography (HR-pQCT). MATERIALS AND METHODS: Twenty human cadaver distal forearm specimens were imaged on a 64- and 320-slice MDCT system at 120 kVp, 200 mA and 135 kVp, 400 mA (in-plane pixel size 234 microm; slice thickness 500 microm). HR-pQCT imaging was performed at an isotropic voxel size of 41 microm. Bone volume fraction (BV/TV), trabecular number (Tb.N), thickness (Tb.Th) and separation (Tb.Sp) were computed. RESULTS: MDCT-derived BV/TV and Tb.Sp were highly correlated (r = 0.92-0.96, p < 0.0001) with the corresponding HR-pQCT parameters. Tb.Th was the only structure measure that did not yield any significant correlation. CONCLUSION: The 64- and 320-slice MDCT systems both perform equally well in depicting trabecular bone architecture. However, because of constrained resolutions accurate derivation of trabecular bone measures is limited to only a subset of microarchitectural parameters.

Assessment of trabecular bone structure of the calcaneus using multi-detector CT: correlation with microCT and biomechanical testing.

The prediction of bone strength can be improved when determining bone mineral density (BMD) in combination with measures of trabecular microarchitecture. The goal of this study was to assess parameters of trabecular bone structure and texture of the calcaneus by clinical multi-detector row computed tomography (MDCT) in an experimental in situ setup and to correlate these parameters with microCT (microCT) and biomechanical testing. Thirty calcanei in 15 intact cadavers were scanned using three different protocols on a 64-slice MDCT scanner with an in-plane pixel size of 208 microm and 500 microm slice thickness. Bone cores were harvested from each specimen and microCT images with a voxel size of 16 microm were obtained. After image coregistration, trabecular bone structure and texture were evaluated in identical regions on the MDCT images. After data acquisition, uniaxial compression testing was performed. Significant correlations between MDCT- and microCT-derived measures of bone volume fraction (BV/TV), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) were found (range, R(2)=0.19-0.65, p<0.01 or 0.05). The MDCT-derived parameters of volumetric BMD, app. BV/TV, app. Tb.Th and app. Tb.Sp were capable of predicting 60%, 63%, 53% and 25% of the variation in bone strength (p<0.01). When combining those measures with one additional texture index (either GLCM, TOGLCM or MF.euler), prediction of mechanical competence was significantly improved to 86%, 85%, 71% and 63% (p<0.01). In conclusion, this study showed the feasibility of trabecular microarchitecture assessment using MDCT in an experimental setup simulating the clinical situation. Multivariate models of BMD or structural parameters combined with texture indices improved prediction of bone strength significantly and might provide more reliable estimates of fracture risk in patients.

CT technology overview: 64-slice and beyond.

Sixty-four-slice CT typified the dramatic race in technical development in radiology. Featuring high spatial resolution with 0.5-mm thin slices and 0.3-second gantry revolution times, it has become state-of-the-art technology in CT imaging shortly after its clinical introduction. Three-dimensional tube modulation together with adaptive x-ray shutters led to significant dose reduction to the patients while improving image quality because of implementation of optimized reconstruction algorithms. The latest innovations-new detector materials, dual-layer detector, dual-source and dynamic volume CT-represent the pinnacles in CT imaging, pursuing different directions to further clinical applications of CT.

Assessment of mitral valve regurgitation at electron-beam CT: comparison with Doppler echocardiography.

PURPOSE: To prospectively compare mitral valve regurgitation fractions calculated at electron-beam computed tomography (CT) (Doppler echocardiography as reference standard) and to evaluate accuracy of electron-beam CT volume and flow measurements compared with magnetic resonance (MR) imaging results. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Volume and flow measurements were performed at electron-beam CT in 219 patients (197 men, 22 women; mean age, 61.5 years +/- 10.4 [standard deviation]), of whom 157 had known isolated mitral valve regurgitation. Regurgitation volume was calculated as the difference between left ventricular total and forward stroke volumes. Regurgitation fractions were compared with corresponding echocardiographic grades (grades 0-IV) by using Spearman rank correlation and a weighted kappa test. In 22 patients, CT volume and flow measurements were compared with MR results by using intraclass correlation. RESULTS: Regurgitation fractions at CT correlated well with echocardiographic grading (rank correlation coefficient, r(S) = 0.82; P < .05). Mean regurgitation fractions for echocardiographic grades 0, I, II, III, and IV were 3.1% +/- 6.2, 12.7% +/- 9.9, 25.3% +/- 12.3, 40.4% +/- 11.5, and 55.9% +/- 13.7, respectively. The most suitable thresholds for differentiating echocardiographic grades were calculated regurgitation fractions of 6%, 20%, 30%, and 44%; with these thresholds, individual echocardiographic grades were differentiated (grades 0 vs I-IV, 0-I vs II-IV, 0-II vs III-IV, and 0-III vs IV, respectively) with sensitivities of 89%, 87%, 86%, and 93% and specificities of 81%, 87%, 92%, and 91%, respectively. There was perfect agreement in classification of mitral valve insufficiency between electron-beam CT and echocardiography in 134 (61%) patients and a mismatch by one grade in 72 (33%) and by two grades in 13 (6%) (kappa = 0.84). Intraclass correlation coefficients between CT and MR imaging for total and forward stroke volumes and regurgitation volume and fraction were 0.88, 0.79, 0.93, and 0.89, respectively. CONCLUSION: Electron-beam CT provides quantitative information on severity of mitral valve regurgitation, but semiquantitative classification of regurgitation showed mismatch between electron-beam CT and Doppler echocardiography by at least one grade in more than one-third of all patients.