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At least 109 records · Page 6Linked to original sources
PubMed1999

Evaluation of impedance technique for detecting breast carcinoma using a 2-D numerical model of the torso.

Previous experimental studies showed that significant changes occur in the electrical properties of breast cancer tissue compared to the surrounding normal tissue. This phenomenon motivated studies on cancer detection using electrical impedance techniques. In the present study, a two-dimensional model of the torso and a numerical method were used to investigate the changes in the potential distribution as a result of a malignant tissue present in the breast. A transverse MRI image of the woman's torso was scanned. Noise reduction and contour-following algorithms were applied to differentiate between eight compartments in the torso. The extracted tissue types were lungs, blood, ribs, bone marrow of the cord, breast fat, skin, skeletal muscle, and heart muscle. Isotropic homogeneous conductivity was assigned to each one of these compartments. The volume conductor problem was solved numerically using the finite volume method to determine the potential distribution developed due to the dipole source. Cases without and with artificially inserted malignant region with realistic sizes were examined to investigate the sensitivity of impedance techniques to detect breast cancer. Significant changes were detected in the potential distribution inside the volume conductor as a result of the realistic size of breast tumors. A linear relation was found between the surface potential in the vicinity of the tumor region and the size of the tumor. For a small malignant area of 0.22 cm2, the surface potential near the tumor region decreased only slightly from a value of 13.81 mV in the normal case to 13.67 mV (0.14 mV change; 1.0%). For a larger malignant area of 5.43 cm2, the potential decrease was more pronounced, 11.29 mV (2.52 mV change; 18.3%), indicating that realistic sizes of breast tumor result in significant changes in the surface potential. Thus, impedance techniques employed in the present study show very good promise in detecting breast cancer.

Algorithms↗
PubMed2004

Penetrating torso trauma: triple-contrast helical CT in peritoneal violation and organ injury--a prospective study in 200 patients.

PURPOSE: To assess the accuracy of computed tomography (CT) in demonstrating the presence or absence of peritoneal violation and type of intraperitoneal organ injury, if any, in hemodynamically stable patients with penetrating torso trauma but without definite peritoneal signs or radiographic evidence of free intraperitoneal air. MATERIALS AND METHODS: During a 29-month period, helical CT with oral, rectal, and intravenous contrast material (triple-contrast) was performed in 200 hemodynamically stable patients, including 169 men (age range, 15-85 years; mean age, 31 years) and 31 women (age range, 17-45 years; mean age, 28 years) with penetrating torso trauma. The study group included 86 patients with gunshot wounds, 111 with stab wounds, and three impaled by sharp objects. CT scans were evaluated prospectively by three trauma radiologists for evidence of peritoneal violation to determine injury to intra- or retroperitoneal solid organs, bowel, mesentery, vascular structures, diaphragm, and urinary tract. Sensitivity, specificity, and accuracy of CT in the diagnosis of peritoneal violation were determined. RESULTS: CT findings aided diagnosis of peritoneal violation in 34% of patients (68 of 200) and were negative for peritoneal violation in 66% of patients (132 of 200). Two patients with negative CT findings failed to improve with observation and underwent therapeutic laparotomy. CT had 97% sensitivity (66 of 68 findings), 98% specificity (130 of 132 findings), and 98% accuracy (196 of 200 findings) for peritoneal violation. CT aided diagnosis of 28 hepatic, 34 bowel or mesenteric, seven splenic, and six renal injuries. Laparotomy based on CT findings in 38 patients was considered therapeutic in 87% (33 of 38) and nontherapeutic in 8% (three of 38) and had negative results in 5% (two of 38). CONCLUSION: Triple-contrast helical CT accurately demonstrates peritoneal violation and visceral injury in patients with penetrating torso wounds.

Abdominal Injuries↗
PubMedDate not supplied

Liver lesions in rats associated with wrapping of the torso.

Liver lesions were noted in control and dosed rats from a percutaneous toxicity study that involved wrapping of the torso to prevent oral ingestion following dermal application of test articles. Further investigation in a follow-up study revealed that the liver lesions were related to wrapping of the torso rather than to test-article administration because the liver lesions only appeared in wrapped animals, including sham-treated controls, but not in naive control animals. The liver lesions, which included centrilobular coagulative necrosis, inflammatory cell infiltration around biliary tracts, histiocytosis, fibrosis, and granulomatous inflammation, were compatible with infarction and associated inflammatory and reparative changes. There was no discernible pattern of involvement of specific hepatic lobes or regions of lobes. Many of the lesions were sufficiently severe to be considered life-threatening. This potentially significant complication should be considered when developing study protocols that involve wrapping of the torso of rats, and consideration should be given to inclusion of a naive control group that is not wrapped.

Animals↗
PubMed2006

Torso vascular trauma at an urban level I trauma center.

Injuries to the great vessels of the torso are more commonly seen and managed in busy urban trauma centers. This same injury complex is rarely seen in military conflicts, likely due to the high kinetic energy wounding mechanisms seen in this setting. While most of the great advancements in trauma surgery over the past century have generally resulted from our wartime experience, civilian centers have contributed greatly to the understanding and management of torso vascular injuries. The presentation and management of injuries to the great vessels of the torso from major penetrating and blunt trauma are reviewed.

Abdomen↗
PubMed1997

Torso signalling regulates terminal patterning in Drosophila by antagonising Groucho-mediated repression.

Patterning of the non-segmental termini of the Drosophila embryo depends on signalling via the Torso receptor tyrosine kinase (RTK). Activation of Torso at the poles of the embryo triggers restricted expression of the zygotic gap genes tailless (tll) and huckebein (hkb). In this paper, we show that the Groucho (Gro) corepressor acts in this process to confine terminal gap gene expression to the embryonic termini. Embryos lacking maternal gro activity display ectopic tll and hkb transcription; the former leads, in turn, to lack of abdominal expression of the Krüppel and knirps gap genes. We show that torso signalling permits terminal gap gene expression by antagonising Gro-mediated repression. Thus, the corepressor Gro is employed in diverse developmental contexts and, probably, by a variety of DNA-binding repressors.

Abdomen↗
PubMed2001

Triple-contrast helical CT in penetrating torso trauma: a prospective study to determine peritoneal violation and the need for laparotomy.

OBJECTIVE: A prospective study was performed to determine the usefulness of triple-contrast helical CT in predicting peritoneal violation and the need for laparotomy in the treatment of penetrating torso trauma. SUBJECTS AND METHODS: Triple-contrast helical CT scans were obtained in 104 hemodynamically stable patients with penetrating injuries to the torso (thoracoabdominal region including tangential wounds to the anterior abdomen, flank, back, and pelvis) over a 17-month period. The study group included 54 patients with gunshot wounds and 50 with stab wounds. No patient had a radiographic or clinical indication for immediate laparotomy. A positive finding on CT was defined as evidence of peritoneal violation or injury to the retroperitoneal colon, major vessel, or urinary tract. Patients with a positive CT, except patients with isolated liver injury or free fluid, underwent laparotomy. Patients with a negative finding on CT were initially observed. RESULTS: CT studies were positive in 35 (34%) of 104 patients and negative in 69 (66%) of 104 of patients. Laparotomy was performed in 21 (60%) of 35 patients with positive CT; 19 (86%) of 22 were therapeutic, two (9%) were nontherapeutic, and one (5%) was negative (no injury was found). Nine patients with isolated hepatic injuries were successfully treated without laparotomy. Among patients with a negative CT, 67 (97%) of 69 were treated nonoperatively with success. CT had 100% (19/19) sensitivity, 96% (69/72) specificity, 100% (69/69) negative predictive value, and 97% (101/104) accuracy in predicting the need for laparotomy. CONCLUSION: Triple-contrast helical CT can accurately predict the need for laparotomy and exclude peritoneal violation in penetrating torso trauma including tangential abdominal wounds.

Abdominal Injuries↗
PubMed1999

"Torso Rotation" experiments. 4: the role of vision and the cervico-ocular reflex in compensation for a deficient VOR.

Acute, reversible changes in human vestibular function can be produced by exposure to "Torso Rotation" (TR), a method involving the overuse of certain types of simple, self-generated movements. A single session results in multiple, short-lasting aftereffects, including perceptual illusions, VOR gain reduction, gaze and postural instability, and motion sickness. With repeated exposure, motion sickness susceptibility disappears and gaze stability improves. VOR gain continues to be reduced, however. Therefore, another gaze stabilizing system must come into play. Are visual and/or neck inputs involved in this functional compensation? Six subjects participated in this 7-day experiment. Eye and head movements were measured during 2 tests: 1) voluntary "head only" shaking between 0.3 and 3.0 Hz (lights off) and 2) voluntary "head and torso" shaking, moving the upper body en bloc (neck immobilized). Measurements were obtained before and repeatedly after TR. Velocity gain (eye velocity/head velocity) was determined for each of these tests. Each day, mean velocity gain during "head only" shaking in the dark (averaged over 1.0 to 2.0 Hz) dropped significantly after TR (P < 0.01), with no long-term improvement (P > 0.9). Similar results, although more noisy, were obtained for "head and torso" shaking. As a control, EOG calibration data confirmed that gaze stability in the light did improve over the 7 days of testing. This experiment demonstrates that the reduction in gaze instability following repeated exposure to TR results from an increased use of vision. It excludes the VOR, the COR, and predictive mechanisms (including efference copy) as contributors. In addition, in the 20 minutes following TR completion, gaze stability recovered less than during previous VOR testing in the dark. These results are compatible with the motion that exposure to TR leads to a change in sensorimotor strategy involving a de-emphasis of vestibular inputs.

Adult↗
PubMed2004

[Individual temperature management during thoracoabdominal aortic aneurysm repair using separate perfusion of upper and lower torso].

We report thoracoabdominal aortic aneurysm repair using separate perfusion of upper and lower torso that can control temperature of each organ individually. This novel modality can maintain mild hypothermic organ perfusion in upper torso and protect the heart under empty beating, while lower torso is further cooled to protect the spinal cord and visceral organs. Therefore this technique may be useful for patients with heart disease who require complex reconstruction of the intercostal arteries or visceral branches. We used this technique successfully in a patient who has a history of surgical repair of the aortic arch and the abdominal aorta. A 70-year-old male who had a history of abdominal aortic aneurysm repair and aortic arch aneurysm repair using stented elephant trunk underwent Crawford's type II thoracoabdominal aortic aneurysm repair. Three pairs of the intercostal arteries and 4 visceral branches were reconstructed using this technique successfully.

Aged↗
PubMed2006

Pre-processing range data for the analysis of torso shape and symmetry of scoliosis patients.

This paper presents a procedure for pre-processing and reconstructing surface scans comprising an interactive technique for cropping stray points and extremities. The procedure involves three stages: cross-sectioning and clipping, hole-filling and sub-sampling, and surface re-generation. The accuracy of the reconstruction obtained was assessed by creating different patterns of holes and stray points on 30 models of the torso and pre-processing the models using the proposed procedure and existing procedures based on Bezier interpolation and Moving Least Squares (MLS) interpolation. Results obtained indicate that the proposed procedure was at least as good as the better of Bezier and MLS interpolation for all the models tested, particularly outperforming both procedures when holes account for up to 5% of the surface. Its accuracy of reconstruction ranged from 90-100% compared to 80-100% for Bezier and 50-100% for MLS. This work is a crucial step in developing techniques for understanding and assessing changes in torso shape and symmetry from torso surface scans of scoliosis patients.

Alberta↗
PubMed1995

Dosimetry of copper-64-labeled monoclonal antibody 1A3 as determined by PET imaging of the torso.

UNLABELLED: We present biodistribution and dosimetry results for 64Cu-benzyl-TETA-MAb 1A3 from 15 human subjects injected with this tracer as determined by serial PET imaging of the torso. METHODS: PET imaging was used to quantify in vivo tracer biodistribution at two time points after injection. Absorbed dosimetry calculated using MIRD-11 and the updated MIRDOSE3 was compared with estimates obtained using rat biodistribution data. RESULTS: By measuring activity concentrations in the torso, and extrapolating for the whole body using standard organ and tissue volumes, we were able to account for 93% of the injected radiopharmaceutical over a range of imaging times from 0 to 36 hr postinjection. Based on PET imaging and the MIRD-11 schema, the liver and spleen are the critical organs with average absorbed doses of 0.12 and 0.10 mGy/MBq (0.44 and 0.39 rad/mCi). The revised MIRDOSE3 scheme yields similar values for these and other organs but also results in a dose of 0.14 mGy/MBq (0.53 rad/mCi) to the heart wall. In the rat, the large intestine is the critical organ at 0.14 mGy/MBq (0.52 rad/mCi), while liver and kidneys each receive 0.11 mGy/MBq (0.41 rad/mCi). Some disparities in absorbed doses determined by these methods are evident but are a result of dissimilar biodistributions in rats and humans. For most organs, rat extrapolated values are higher than the human measurements with PET. CONCLUSION: This study shows that torso PET imaging can quantitatively measure the whole-body biodistribution of a radiopharmaceutical as long as it has relatively slow pharmacokinetics.

Animals↗
PubMed1996

Support for a linear length-tension relation of the torso extensor muscles: an investigation of the length and velocity EMG-force relationships.

This study investigated the hypothesis that the length-tension relation of the torso erectors would be linear, mirroring the observed linear increase in extension strength capability toward full flexion. The effect of torso extension velocity on the tension capability of these muscles was also investigated for common motion speeds. A myoelectric-based approach was used wherein a dynamic biomechanical model incorporating active and passive tissue characteristics provided muscle kinematic estimates during controlled sagittal plane extension motions. A double linear optimization formulation from the literature provided muscle tension estimates. The data of five male subjects supported the hypothesis of a linear length-tension relation toward full flexion for both the erector spinae and latissimus muscles. Velocity trends agreed with the predicted by Hill's exponential relation, although linear trends were found to fit the data almost as well. The results have implications for muscle tension estimation in biomechanical torso modeling, and suggest a possible low back pain injury mechanism through tissue strain while lifting in fully flexed postures.

Abdominal Muscles↗
PubMedDate not supplied

Reconstruction of oncologic torso defects: emphasis on microvascular reconstruction.

A large variety of pedicle flaps centered at the shoulder girdle or pelvic girdle, or derived from the epigastric axis, are generally available to reconstruct defects of the torso. However, microvascular free flap reconstruction may occasionally be required for: 1) locations that are difficult to reach with pedicle flaps (the posterolateral iliac crest region, epigastrium, lower lumbar and sacral, and upper back and lower central); 2) locations in which muscles or their vascular pedicles have been destroyed by surgical ablation or irradiation; 3) a large-volume "dead space" or a large surface area that may be inadequately covered by available regional flaps; and 4) a combination of factors. Whether using a pedicle or free flaps, the reconstructive requirements of torso reconstruction must be met: 1) to restore chest wall or abdominal wall integrity, 2) to fill "dead space," 3) to cover vital exposed structures, 4) to maintain skeletal stability of the thoracic cage and minimize respiratory compromise, and 5) to buttress visceral repairs. Semin. Surg. Oncol. 19:255-263, 2000.

Abdominal Neoplasms↗
PubMed2005

Intraindividual comparison of 1.0 M gadobutrol and 0.5 M gadopentetate dimeglumine for time-resolved contrast-enhanced three-dimensional magnetic resonance angiography of the upper torso.

PURPOSE: To compare the signal characteristics and bolus dynamics of 1.0 M gadobutrol and 0.5 M Gd-DTPA for time-resolved, three-dimensional, contrast-enhanced (CE) MRA of the upper torso. MATERIALS AND METHODS: Ten healthy volunteers were examined with time-resolved three-dimensional CE-MRA (scan time per three-dimensional data set: 0.86 second; voxel size: 3.6 x 2 x 6.3 mm(3)). Each volunteer underwent eight individual examinations after intravenous injection of 0.05 and 0.1 mmol/kg body weight (b.w.) of 1.0 M gadobutrol and 0.5 M Gd-DTPA using two injection rates (2.5 and 5 mL/second). The data analysis included quantitative measurements of the peak signal-to-noise ratio (SNR) and bolus dispersion (full width at half maximum (FWHM)) in the pulmonary artery, left atrium, and thoracic and abdominal aortas. RESULTS: No significant differences in the peak SNR and bolus dispersion were observed between gadobutrol and Gd-DTPA for all dose levels and injection rates in any of the vascular segments. For both contrast agents a dose of 0.1 mmol/kg b.w. injected with 5 mL/second achieved the highest SNR in all vascular segments. CONCLUSION: For the imaging parameters used in this study, higher-concentrated gadolinium chelates offer no relevant advantages for time-resolved three-dimensional CE-MRA of the upper torso.

Body Mass Index↗
PubMed1996

The activity of D-raf in torso signal transduction is altered by serine substitution, N-terminal deletion, and membrane targeting.

The Raf family of serine/threonine kinases are essential components in many receptor tyrosine kinase-mediated signal transduction pathways. Here, we analyze the function of D-raf in the Torso (Tor) pathway required to specify cellular fates at the embryonic poles. Using mutant embryos lacking endogenous D-raf protein, we show that D-raf's serine/threonine kinase activity is essential for its role in Tor signal transduction and that human Raf-1 will substitute for D-raf in this pathway. After Tor activation, D-raf becomes hyperphosphorylated. We identified two putative serine phosphorylation sites (S388 and S743) in SF9 cells and demonstrate that S743 or its phosphorylation is essential for D-raf function in embryos. Alanine substitution at S388, N-terminal truncation, or targeted membrane association permits transmission of the Torso signal by D-raf, but these D-raf molecules differ in their rescuing potential and relative biological activity. Membrane-targeted D-raftor4021 showed the highest level of activity, followed by alanine-substituted D-rafS388A and N-terminal-truncated D-raf delta 445. Since the activity profiles for these altered forms of D-raf are distinct, these findings indicate that each structural modification differentially affects the regulation and/or propagation of the Tor signal by these mutant D-raf proteins.

Alanine↗
PubMed1989

Combination of facial rejuvenation and lipoplasty of the torso.

Older women seeking facial rejuvenation often exhibit another sign of middle age--the accumulation of subcutaneous fat in the torso. In the author's practice a total body evaluation approach is used. It is often suggested that the patient combine facial rejuvenation with lipoplasty of the torso if the patient is a good surgical candidate and the procedures can be performed jointly in less than six hours. The advantages are many, including a single convalescent period, decreased costs, and very high patient satisfaction with the degree of makeover in one session.

Abdominal Muscles↗
PubMedDate not supplied

Investigation of Frank's vectorcardiographic lead system on homogeneous rabbit torso model.

The applicability of Frank's lead system in experiments on rabbits is studied by using a homogeneous rabbit torso model. The influence of dipole localization on the modules of the lead vectors at the level of 4th, 5th and 6th intercostal spaces is studied. The lead vector modules along the axes X, Y and Z for the level of the dipole are calculated to be equal to 1:0.99:0.92. The maximum angular errors in the planes XY, XZ and YZ are calculated, being for the same level theta yz = -6 degrees 50', theta xy = theta xz = 0 degrees 00'. The authors have reached the conclusion that Frank's system produces good levelling of the lead vector modules and has satisfactory orthogonality on rabbit torso model.

Animals↗
PubMed1994

Minimum-norm estimation in a boundary-element torso model.

The paper deals with the bioelectric and biomagnetic inverse problems. The authors present a method to estimate primary-current distributions in a homogeneous, realistically shaped boundary-element torso model. The reconstruction surface is triangulated to keep the procedure computationally feasible. The minimum-norm estimate is computed on the basis of separate electric and magnetic signals, as well as from combined data. The method can be used both for heart and brain studies. Simulation results for current-dipole sources in a homogeneous realistic torso are discussed.

Electrophysiology↗
PubMed2005

Effect of torso shape and heart location in the chest on formation of cardiac electric potentials on body surface in dogs.

Experimental and theoretical methods were employed to study the effects of torso shape and heart orientation in the thoracic cavity on peculiarities of the formation cardiac electric field on the body surface in dogs. It was found that heart orientation to a greater extent than torso shape affected projections of cardiac electric potentials from the epicardium onto the body surface.

Animals↗