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Role of MRI in the Evaluation of Thoracoabdominal Emergencies.
Ludwig, DR, Raptis, CA, Broncano, J, Bhalla, S, Luna, A
Topics in magnetic resonance imaging : TMRI. 2020;(6):355-370
Abstract
Thoracic and abdominal pathology are common in the emergency setting. Although computed tomography is preferred in many clinical situations, magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) have emerged as powerful techniques that often play a complementary role to computed tomography or may have a primary role in selected patient populations in which radiation is of specific concern or intravenous iodinated contrast is contraindicated. This review will highlight the role of MRI and MRA in the emergent imaging of thoracoabdominal pathology, specifically covering acute aortic pathology (acute aortic syndrome, aortic aneurysm, and aortitis), pulmonary embolism, gastrointestinal conditions such as appendicitis and Crohn disease, pancreatic and hepatobiliary disease (pancreatitis, choledocholithiasis, cholecystitis, and liver abscess), and genitourinary pathology (urolithiasis and pyelonephritis). In each section, we will highlight the specific role for MRI, discuss basic imaging protocols, and illustrate the MRI features of commonly encountered thoracoabdominal pathology.
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Deep Learning for Automatic Calcium Scoring in CT: Validation Using Multiple Cardiac CT and Chest CT Protocols.
van Velzen, SGM, Lessmann, N, Velthuis, BK, Bank, IEM, van den Bongard, DHJG, Leiner, T, de Jong, PA, Veldhuis, WB, Correa, A, Terry, JG, et al
Radiology. 2020;(1):66-79
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Abstract
Background Although several deep learning (DL) calcium scoring methods have achieved excellent performance for specific CT protocols, their performance in a range of CT examination types is unknown. Purpose To evaluate the performance of a DL method for automatic calcium scoring across a wide range of CT examination types and to investigate whether the method can adapt to different types of CT examinations when representative images are added to the existing training data set. Materials and Methods The study included 7240 participants who underwent various types of nonenhanced CT examinations that included the heart: coronary artery calcium (CAC) scoring CT, diagnostic CT of the chest, PET attenuation correction CT, radiation therapy treatment planning CT, CAC screening CT, and low-dose CT of the chest. CAC and thoracic aorta calcification (TAC) were quantified using a convolutional neural network trained with (a) 1181 low-dose chest CT examinations (baseline), (b) a small set of examinations of the respective type supplemented to the baseline (data specific), and (c) a combination of examinations of all available types (combined). Supplemental training sets contained 199-568 CT images depending on the calcium burden of each population. The DL algorithm performance was evaluated with intraclass correlation coefficients (ICCs) between DL and manual (Agatston) CAC and (volume) TAC scoring and with linearly weighted κ values for cardiovascular risk categories (Agatston score; cardiovascular disease risk categories: 0, 1-10, 11-100, 101-400, >400). Results At baseline, the DL algorithm yielded ICCs of 0.79-0.97 for CAC and 0.66-0.98 for TAC across the range of different types of CT examinations. ICCs improved to 0.84-0.99 (CAC) and 0.92-0.99 (TAC) for CT protocol-specific training and to 0.85-0.99 (CAC) and 0.96-0.99 (TAC) for combined training. For assignment of cardiovascular disease risk category, the κ value for all test CT scans was 0.90 (95% confidence interval [CI]: 0.89, 0.91) for the baseline training. It increased to 0.92 (95% CI: 0.91, 0.93) for both data-specific and combined training. Conclusion A deep learning calcium scoring algorithm for quantification of coronary and thoracic calcium was robust, despite substantial differences in CT protocol and variations in subject population. Augmenting the algorithm training with CT protocol-specific images further improved algorithm performance. © RSNA, 2020 See also the editorial by Vannier in this issue.
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Outpatient Management of Children With World Health Organization Chest Indrawing Pneumonia: Implementation Risks and Proposed Solutions.
McCollum, ED, Ginsburg, AS
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2017;(9):1560-1564
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This Viewpoints article details our recommendation for the World Health Organization Integrated Management of Childhood Illness guidelines to consider additional referral or daily monitoring criteria for children with chest indrawing pneumonia in low-resource settings. We review chest indrawing physiology in children and relate this to the risk of adverse pneumonia outcomes. We believe there is sufficient evidence to support referring or daily monitoring of children with chest indrawing pneumonia and signs of severe respiratory distress, oxygen saturation <93% (when not at high altitude), moderate malnutrition, or an unknown human immunodeficiency virus (HIV) status in an HIV-endemic setting. Pulse oximetry screening should be routine and performed at the earliest point in the patient care pathway as possible. If outpatient clinics lack capacity to conduct pulse oximetry, nutritional assessment, or HIV testing, then we recommend considering referral to complete the evaluation. When referral is not possible, careful daily monitoring should be performed.
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Dual-energy computed tomographic imaging of pulmonary hypertension.
Hachulla, AL, Lador, F, Soccal, PM, Montet, X, Beghetti, M
Swiss medical weekly. 2016;:w14328
Abstract
Dual-energy computed tomography (DECT) angiography of the chest provides a combined morphological and functional analysis of the lung, usually obtained in a single acquisition without extra radiation or injection of extra intravenous iodine contrast. The parenchymal iodine maps generated by DECT are well correlated with scintigraphy, and are becoming an essential tool for evaluating patients with pulmonary vascular diseases. With a single DECT acquisition, complete imaging of pulmonary hypertension is now available, displaying vascular anatomy, parenchymal morphology and functional assessment. Triangular pulmonary perfusion defects in chronic thromboembolic pulmonary hypertension may be clearly analysed even in the presence of distal arterial occlusion. Perfusion heterogeneities seen in patients with pulmonary arterial hypertension reflect mosaic perfusion and may be helpful for the diagnosis, severity assessment and prognosis of the disease. Vascular or parenchymal abnormalities can also be analysed with perfusion defects to determine their aetiology. Pulmonary arterial hypertension due to congenital heart disease can be assessed with a single DECT, even in the neonatal population. Furthermore, new applications are emerging with ventilation imaging or myocardial perfusion imaging obtained by DECT and should be considered. In conclusion, DECT of the thorax enables the simultaneous and noninvasive assessment of vascular anatomy, parenchymal morphology and functional pulmonary imaging in various groups of PH.
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A randomized clinical trial comparing advanced pneumatic truncal, chest, and arm treatment to arm treatment only in self-care of arm lymphedema.
Ridner, SH, Murphy, B, Deng, J, Kidd, N, Galford, E, Bonner, C, Bond, SM, Dietrich, MS
Breast cancer research and treatment. 2012;(1):147-58
Abstract
Treatment of the truncal lymphatics prior to treatment of the lymphedematous arm is an accepted, although not empirically tested, therapeutic intervention delivered during decongestive lymphatic therapy (DLT). Breast cancer survivors with arm lymphedema are encouraged to use these techniques when performing simple lymphatic drainage as part of their life-long lymphedema self-care. Self-massage is at times difficult and pneumatic compression devices are used by many patients to assist with self-care. One such device, the Flexitouch(®) System, replicates the techniques used during DLT; however, the need for application of pneumatic compression in unaffected truncal areas to improve self-care outcomes in arm only lymphedema is not established. The objective of this study was to compare the therapeutic benefit of truncal/chest/arm advanced pneumatic compression therapy (experimental group) verses arm only pneumatic compression (control group) in self-care for arm lymphedema without truncal involvement using the Flexitouch(®) System. Outcomes of interest were self-reported symptoms, function, arm impedance ratios, circumference, volume, and trunk circumference. Forty-two breast cancer survivors, (21 per group), with Stage II lymphedema completed 30 days of home self-care using the Flexitouch(®) System. Findings revealed a statistically significant reduction in both the number of symptoms and overall symptom burden within each group; however, there were no statistically significant differences in these outcomes between the groups. There was no statistically significant overall change or differential pattern of change between the groups in function. A statistically significant reduction in bioelectrical impedance and arm circumference within both of the groups was achieved; however, there was no statistically significant difference in reduction between groups. These findings indicate that both configurations are effective, but that there may be no added benefit to advanced pneumatic treatment of the truncal lymphatics prior to arm massage when the trunk is not also affected. Further research is indicated in a larger sample.
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Influence of hilar deposition in the evaluation of the alveolar epithelial permeability on 99mTc-DTPA aerosol inhaled scintigraphy.
Ogi, S, Gotoh, E, Uchiyama, M, Fukuda, K, Urashima, M, Fukumitsu, N
Japanese journal of radiology. 2009;(1):20-4
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Abstract
PURPOSE We investigated whether hilar radioaerosol deposition affects the clearance rate of technetium-99m-labeled diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) from peripheral alveolar regions. MATERIALS AND METHODS A total of 38 patients underwent (99m)Tc-DTPA inhalation lung scintigraphy. Six region of interest (ROI) patterns were adopted: ROI 1 was outlined around the entire hemithorax, and ROIs 2-6 were outlined around the hemithorax but excluded square ROIs of different size in the hilar region. Half-times (T(1/2) were calculated with time-activity curves using one-compartment and two-compartment analyses. The T(1/2) of ROIs 1-5 were plotted against the T(1/2) of ROI 6, and regression lines were obtained with the least-squares method. The absolute values of the differences between surveyed values and regression line were calculated. The Wilcoxon test for trend and a single linear regression model were used to determine statistical significance. RESULTS There were significant reductions in the absolute values of the differences between surveyed values and regression line from ROIs 1-5 by one-component analysis and the fast component of two-compartment analysis (P < 0.001). CONCLUSION Our results suggest that the deposition of radioaerosol in the hilar region affects the clearance rate of (99m)Tc-DTPA from the alveoli in damaged lungs. The hilar region should be excluded from ROIs when alveolar epithelial permeability is evaluated.
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Effects of experimentally induced pain and fear of pain on trunk coordination and back muscle activity during walking.
Lamoth, CJ, Daffertshofer, A, Meijer, OG, Lorimer Moseley, G, Wuisman, PI, Beek, PJ
Clinical biomechanics (Bristol, Avon). 2004;(6):551-63
Abstract
OBJECTIVE To examine the effects of experimentally induced pain and fear of pain on trunk coordination and erector spinae EMG activity during gait. DESIGN In 12 healthy subjects, hypertonic saline (acute pain) and isotonic saline (fear of pain) were injected into erector spinae muscle, and unpredictable electric shocks (fear of impending pain) were presented during treadmill walking at different velocities, while trunk kinematics and EMG were recorded. BACKGROUND Chronic low back pain patients often have disturbed trunk coordination and enhanced erector spinae EMG while walking, which may either be due to the pain itself or to fear of pain, as is suggested by studies on both low back pain patients and healthy subjects. METHODS The effects of the aforementioned pain-related manipulations on trunk coordination and EMG were examined. Results. Trunk kinematics was not affected by the manipulations. Induced pain led to an increase in EMG variability and induced fear of pain to a decrease in mean EMG amplitude during double stance. CONCLUSIONS Induced pain and fear of pain have subtle effects on erector spinae EMG activity during walking while leaving the global pattern of EMG activity and trunk kinematics unaffected. This suggests that the altered gait observed in low back pain patients is probably a complex evolved consequence of a lasting pain, rather than a simple immediate effect. RELEVANCE Variability of EMG data and kinematics may explain pain-dependent alterations of motor control, which in turn might contribute to a further understanding of the development of movement impairments in low back pain.
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Sodium 3-D MRI of the human torso using a volume coil.
Steidle, G, Graf, H, Schick, F
Magnetic resonance imaging. 2004;(2):171-80
Abstract
Sodium MR imaging is considered to provide clinically important information about the human body that is not achievable by hydrogen-based approaches. However, due to the low natural abundance in biological tissues, sodium signals usually lead to low spatial resolution, low SNR, and long acquisition times compared to conventional 1H imaging, even using well-adapted surface coils. For our study, a volume coil was designed with nearly homogeneous excitation/receive characteristics and a suitable geometry fitting the human torso. A sufficient penetration throughout the entire thorax, abdomen, or pelvis is provided allowing for sodium imaging of the kidneys, the liver with gall bladder, or the myocardium. All measurements were performed on a 1.5 T whole body scanner using a spoiled 3-D gradient echo sequence. Imaging parameters TE, TR, and readout bandwidth were optimized for sensitive recording of the sodium component with slow transverse relaxation. Nonselective RF excitation pulses with a duration of 2.5 ms and rectangular shape were applied to avoid SAR problems. Narrow receiver bandwidth and excitation near the Ernst angle provided clinically practicable examinations with measuring times of less than 15 min at a spatial resolution of 8 x 8 x 8 mm3. Under these conditions, SNR of 11 for the kidneys and vertebral disks, 9 for the spinal canal, and 6 for the liver was achieved. A special 3-D spin echo sequence was used to determine T2, times which resulted to 15.3 +/- 1.1 ms for liver, 27.7 +/- 7.2 ms for kidneys, and 24.0 +/- 4.7 ms for the content of the spinal canal.
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Trunk recruitment during spoon use in tetraparetic cerebral palsy.
van Roon, D, Steenbergen, B, Meulenbroek, RG
Experimental brain research. 2004;(2):186-95
Abstract
In the present study we investigated the extent to which individuals suffering from spastic tetraparesis as a consequence of cerebral palsy tune their trunk involvement to accuracy demands in a spoon-handling task. Twenty-two participants (ten adolescents with spastic tetraparesis and 12 control participants) had to transport a spoon filled with water or sugar to a small or a large bowl that was placed within reach. Even though trunk displacement was larger in the tetraparetic participants than it was in the control participants, the effects of the imposed accuracy constraints were remarkably similar. Participants in both groups increased trunk displacement with increasing precision requirements. Furthermore, in both groups the largest trunk involvement was found in the initial and final part of the substance-transporting phase, when wrist velocity was lowest. We propose several explanations for these findings and conclude that the large trunk involvement in individuals with tetraparetic cerebral palsy should, in any case, not be regarded as a primary symptom of the disorder, but rather as an adaptive reaction to increased task demands.
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Measurement of radiotherapy x-ray skin dose on a chest wall phantom.
Quach, KY, Morales, J, Butson, MJ, Rosenfeld, AB, Metcalfe, PE
Medical physics. 2000;(7):1676-80
Abstract
Sufficient skin dose needs to be delivered by a radiotherapy chest wall treatment regimen to ensure the probability of a near surface tumor recurrence is minimized. To simulate a chest wall treatment a hemicylindrical solid water phantom of 7.5 cm radius was irradiated with 6 MV x-rays using 20x20 cm2 and 10x20 cm2 fields at 100 cm source surface distance (SSD) to the base of the phantom. A surface dose profile was obtained from 0 to 180 degrees, in 10 degrees increments around the circumference of the phantom. Dosimetry results obtained from radiochromic film (effective depth of 0.17 mm) were used in the investigation, the superficial doses were found to be 28% (of Dmax) at the 0 degrees beam entry position and 58% at the 90 degrees oblique beam position. Superficial dose results were also obtained using extra thin thermoluminescent dosimeters (TLD) (effective depth 0.14 mm) of 30% at 0 degrees, 57% at 90 degrees, and a metal oxide semiconductor field effect transistor (MOSFET) detector (effective depth 0.5 mm) of 43% at 0 degrees, 62% at 90 degrees. Because the differences in measured superficial doses were significant and beyond those related to experimental error, these differences are assumed to be mostly attributable to the effective depth of measurement of each detector. We numerically simulated a bolus on/bolus off technique and found we could increase the coverage to the skin. Using an alternate "bolus on," "bolus off" regimen, the skin would receive 36.8 Gy at 0 degrees incidence and 46.4 Gy at 90 degrees incidence for a prescribed midpoint dose of 50 Gy. From this work it is evident that, as the circumference of the phantom is traversed the SSD increases and hence there is an inverse square fluence fall-off, this is more than offset by the increase in skin dose due to surface curvature to a plateau at about 90 degrees. Beyond this angle it is assumed that beam attenuation through the phantom and inverse square fall-off is causing the surface dose to reduce.