[Differential x-ray diagnosis of peripheral formations in the lungs by use of electronic computers. 1. A table of signs and symptoms].
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Computers↗
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Indication for preoperative localization of small peripheral pulmonary nodules in thoracoscopic surgery.
OBJECTIVE: Widespread clinical use of helical computed tomography has improved the detection rate for small peripheral pulmonary nodules. As a result, use of thoracoscopic surgery to confirm the diagnosis of small peripheral pulmonary nodules has become more important than ever before. However, if small peripheral pulmonary nodules are too small or located too deeply to detect thoracoscopically, it is necessary to mark the small peripheral pulmonary nodules preoperatively. The purpose of this study was to determine indications for preoperative hookwire marking in thoracoscopic resection of small peripheral pulmonary nodules. METHODS: A total of 120 patients underwent thoracoscopic pulmonary resection in our institute from 1999 to 2001. Small peripheral pulmonary nodules were marked preoperatively in 61 of these patients by means of percutaneous placement of a hookwire under computed tomographic guidance. The hookwire-marked small peripheral pulmonary nodules either were smaller than 10 mm or were located more than 10 mm below the pleural surface. RESULTS: Although 9 of the hookwire-marked small peripheral pulmonary nodules were easily identified during thoracoscopy, the other 52 small peripheral pulmonary nodules could not have been identified during thoracoscopy without the hookwire marking. Of the 59 small peripheral pulmonary nodules that were not hookwire marked, 7 required conversion to thoracotomy to locate the nodules. Small peripheral pulmonary nodules from both groups were examined and assigned to either an undetectable or detectable group. Discriminant function analysis indicated that a linear function (ie, depth = 0.836 x size - 2.811) could be used to differentiate between undetectable and detectable small peripheral pulmonary nodules, and preoperative hookwire marking for small peripheral pulmonary nodules should be considered for nodules in the region above those. CONCLUSION: The results suggest that this formula might serve as an indication for preoperative marking of small peripheral pulmonary nodules in thoracoscopic resection.
Female↗
The role of power Doppler sonography in the evaluation of superficial soft tissue abscesses.
OBJECTIVE: To evaluate the efficacy of power doppler ultrasonography in depicting increased vasculature and hyperemia around the superficial soft tissue abscess. MATERIALS AND METHODS: 21 patients with soft tissue abscess were evaluated with gray scale imaging, color doppler sonography, power doppler sonography and computed tomography. In each case attempts were made using power doppler sonography to demonstrate any areas of increased vascularity around the lesion. The results were compared with computed tomographic findings. RESULTS: Peripheral hyperemia and increased vasculature were demonstrated with power doppler sonography in 19 of 21 patients with soft tissue abscess. The hyperemic area demonstrated around the wall of the abscess by power doppler sonography was similar to the enhanced area shown by computed tomography performed after contrast administration. CONCLUSION: Power doppler sonography shows increased vasculature and hyperemia in the wall of abscesses. Therefore, power doppler sonography can be used to assist with the diagnosis of superficial soft tissue abscess.
Abscess↗
Computer-controlled lidocaine infusion for the evaluation of neuropathic pain after peripheral nerve injury.
BACKGROUND: Systemic lidocaine has been reported to be effective in treating several neuropathic pain syndromes. Few reports relate plasma lidocaine concentration to analgesia and the available studies have been complicated by labile plasma lidocaine concentrations. We used a computer-controlled infusion pump (CCIP) to target and maintain stable plasma lidocaine concentrations and study the effect of intravenous lidocaine on (1) pain scores, (2) current perception thresholds, (3) side effects, and (4) pain distribution in patients suffering from peripheral nerve injury pain. METHODS: This study used a randomized double-blind placebo-controlled design. Eleven patients suffering from neuropathic pain after peripheral nerve injury received both a lidocaine and saline infusion in separate study sessions. The order of the study sessions was randomized and separated from each other by 1 week. The CCIP was programmed to target plasma lidocaine concentrations of 0.5, 1, 1.5, 2, and 2.5 micrograms/ml, each held for 10 min. Pain scores and pain distribution were assessed in the painful area, and electrical current perception thresholds (CPT) of the ring finger were measured using a cutaneous perception threshold neurometer (Neurometer CPT, Neurotron, Baltimore, MD). Side effects were recorded at fixed intervals. Plasma lidocaine concentrations were measured at 4 and 9 min after each step increase in infusion and correlated with the observed effects. RESULTS: Saline infusion had no effect. However, with lidocaine there was a significant plasma concentration-dependent decrease in pain scores starting at 1.5 micrograms/ml. This effect typically corresponded with a decrease in the size of the receptive field to which the pain was referred. For the electrical stimulus, there was no significant effect on cutaneous perception at 2000-Hz stimulation at the highest concentration examined; however, there was a significant increase in thresholds at 250-Hz (starting at 1.5 micrograms/ml) and 5-Hz (starting at 1.0 micrograms/ml) stimulation. There were no serious side effects. In all, 54.5% of patients reported lightheadedness (average plasma lidocaine concentration: 1.5 micrograms/ml) and one patient reported nausea (2.3 micrograms/ml). DISCUSSION: The computer-controlled delivery of intravenous lidocaine results in relatively stable plasma concentrations which allows a more thorough evaluation of the relationship between plasma concentration and patient response. This administration methodology for intravenous lidocaine may prove to be a valuable clinical and research tool.
Adult↗
Image feature analysis and computer-aided diagnosis in digital radiography. 3. Automated detection of nodules in peripheral lung fields.
We are investigating the characteristic features of lung nodules and the surrounding normal anatomic background in order to develop an algorithm of computer vision for use as an aid in the detection of nodules in digital chest radiographs. Our technique involves an attempt to eliminate the background anatomic structures in the lung fields by means of a difference image approach. Then, feature-extraction techniques, such as tests for circularity, size, and their variation with threshold level, are applied so that suspected nodules can be isolated. Preliminary results of this automated detection scheme yielded high true-positive rates and low false-positive rates in the peripheral lung regions of the chest. This detection scheme, which can assist the final diagnosis by the clinician, has the potential to improve the early detection of lung carcinomas.
Diagnostic Errors↗
A model of the peripheral auditory system.
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Animals↗
Hemodynamics and autonomic control of heart rate turbulence.
INTRODUCTION: Late heart rate deceleration parallels the increase of systolic blood pressure during heart rate turbulence (HRT) after ventricular premature complexes (VPC). This is consistent with the involvement of baroreflex mechanism. Physiological background of systolic blood pressure dynamics is not known. Enhanced sympathetic activation and nonautonomic post-VPC changes of stroke volume have been speculated on. METHODS AND RESULTS: We studied 28 subjects (aged 56 +/- 11 years; 20 males; 18 normal and 10 abnormal left ventricular (LV) function) with spontaneous occurrence of VPCs. HRT indices and baroreflex sensitivity were analyzed from the ECGs and finger arterial pressure recordings during 30 minutes of spontaneous respiration in supine position. Beat-by-beat stroke volume and peripheral vascular resistance were computed by a nonlinear, self-adaptive model of aortic input impedance (Modelflow, Finapres Medical Systems, Arnhem, The Netherlands). Indices of HRT and baroreflex sensitivity were highly correlated. In patients with preserved LV function, there was no substantial dynamics of stroke volume in the late phase after VPC, while peripheral vascular resistance increased significantly. In patients with impaired LV function, potentiated first sinus beat after VPC triggered transient hemodynamic alternans. Dynamics of peripheral vascular resistance was attenuated and stroke volume was depressed in the late phase after VPC. CONCLUSIONS: Delayed sympathetically mediated vasomotor response to VPC produces systolic blood pressure overshoot. This subsequently induces vagally mediated late heart rate deceleration. Under physiologic conditions, there is no evidence of other hemodynamic and/or mechanical effect outside the autonomic reflex arch. In patients with LV dysfunction, both depressed vagal and sympathetic modulation and, indirectly, enhanced postextrasystolic potentiation account for attenuated HRT.
Analysis of Variance↗
[Experiences with computer-assisted x-ray diagnosis of pulmonary coin lesions (author's transl)].
Favourable results of the computer-aided diagnosis of peripheral bronchial carcinoma lead to a simplified scheme for calculation fo diagnosis, basing upon X-ray symptoms. This scheme was tested in the Zentralinstitut für Krebsforschung (ZIK) in 102 pateints and in the Forschungsinstitut für Lungenkrankheiten und Tuberkulose (FLT) in 101 patients. These patients had coin lesions of the lung with unknown diagnoses. The histological diagnoses later proved were compared with the calculated diagnoses. In ZIK there were correct diagnosis in 92.16% (in 96.53% of the carcinomas, in 44.4% of the tuberculomas and in all benign tumors), while in FLT 85.53% of the coin lesions were correctly classified (89.13% of carcinomas, 79.31% of the tuberculomas and all benign tumors). The comparison with the clinical-histological diagnoses showed a clear improvement of the accuracy by the calculated diagnoses. The method can be recommended for the basic diagnosis especially of peripheral bronchial carcinoma. It implies a reduction of the diagnostic delay, but it can not substitute the histologic investigation of the lesions.
Adult↗
Peripheral artery stent visualization and in-stent stenosis analysis in 16-row computed tomography: an in-vitro evaluation.
The accuracy of 16-row multidetector CT in the visualization of different peripheral artery stents and in the appraisal of in-stent stenosis was assessed. Nine different stent types (nitinol and stainless steel) with three diameters (6, 8 and 10 mm) were used; altogether 27 stents were analyzed in a barrel-shaped vascular model. Low-grade (<40%) and high-grade (>60%) in-stent stenoses were simulated by polyurethane sticks (70 HU) of differing diameters (2-6 mm). Imaging was performed with 16x0.75-mm detector collimation, 130 mAs, 120 kV, 12-mm table feed/rotation, 1.0-mm slice thickness and 0.5-mm increment. The stent diameter, strut thickness, in-stent attenuation values, degree and degree of in-stent stenosis were evaluated. Nitinol stents showed significantly (P<10-6) less stent lumen narrowing, artificial strut thickening and overestimation of the degree of in-stent stenoses than stainless steel stents. In-stent attenuation values and artificial strut thickening were significantly (P<10-6) lower in 10- and 8-mm stents than in 6-mm stents. Stent lumen narrowing was significantly less in 10-mm stents than in 8-mm (P<10-4) or 6-mm (P<10-6) stents. In-stent stenoses were significantly overestimated, irrespective of the stent diameter. In 6-mm stents overestimation was significantly higher than in 8-mm (P<0.01) or 10-mm stents (P<10-6). Under in-vitro conditions 16-row MDCT allowed an accurate identification of in-stent stenosis, but significantly overestimated the effective degree of the stenosis.
Constriction, Pathologic↗
Far-field potentials in muscle.
Far-field potentials have been predicted by computer simulations as well as demonstrated in both animals and humans with respect to the peripheral and central nervous systems. Computer simulations have also predicted far-field potentials originating at the termination of muscle tissue. This investigation demonstrates the occurrence of 2 far-field potentials in the human biceps muscle resulting from action potential termination at the musculotendonous junctions. A monophasic potential is produced at both the muscle's origin and insertion, and the polarity is entirely dependent upon the recording montage. Sequential stimulation of the biceps muscle at 2.5-cm increments resulted in the 2 far-field potentials and their respective latencies changing proportional to the distance between the stimulus site and the 2 musculotendonous junctions. Various stimulation and recording montages are used to investigate the properties of these far-field potentials. The leading/trailing dipole model is utilized to explain the production and polarity of far-field potentials generated by muscle tissue.
Action Potentials↗
Transient abdominal granulomas in children.
Space-occupying liver lesions in febrile patients are usually caused by tumor or infection and other causes are seldom encountered. In five patients age 20 months to 12 years who were evaluated for fever of unknown origin, imaging studies revealed hepatic nodules consisting of transient, sterile granulomas for which no cause could be determined. Stellate architecture histologically supported clinical evidence of subacute bacterial infection. Imaging modalities included: 99Tc-sulfur colloid (n = 2) and 67Ga (n = 2) scintigraphy; ultrasound (n = 5); computed tomography (n = 4); and magnetic resonance imaging (n = 2). Peripheral low density, as revealed by computed tomography in one and hyperintense halos on magnetic resonance imaging of another patient are both considered predictive for neoplastic disease but were associated with granulomas. The differential diagnosis of macroscopic liver lesions seen on imaging studies in febrile children should include the possibility of transient, idiopathic granulomas.
Child↗
[Characteristics of central and peripheral hemodynamics in infants with hemolytic disease of newborn].
Overall 82 full-term neonates (52 children with hemolytic disease and 30 healthy neonates) were examined. The general circulation was investigated over time (on days 1, 3.5-7 of life). Use was made of echocardiography and monitor studies of arterial pressure and heart rate; lability of arterial pressure and general peripheral vascular resistance were computed. As a result of the studies and correlations, it has been revealed that neonates with hemolytic disease manifest appreciable disorders of the cardiovascular system, correlating with the disease gravity. Earlier times of the closure of fetal communications were established as were the hyperkinetic type of +cardiac hemodynamics, arterial hypotension accompanied by arterial pressure instability and a decrease of the general peripheral vascular resistance which should be taken into consideration in choosing therapeutic measures.
Cardiovascular System↗
Computed tomography fluoroscopy-guided lumbar sympathectomy for a patient with peripheral vascular disease and lumbar spine compression fracture.
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Arteriosclerosis↗
Neural network classification of nerve activity recorded in a mixed nerve.
Whole-nerve cuff electrodes can be used to record electrical nerve activity in peripheral nerves and are suitable for chronic implantation in animals or humans. If the whole nerve innervates multiple target organs or muscles then the recorded activity will be the superposition of the activity of different nerve fibers innervating these organs. In certain cases it is desirable to monitor mixed nerve activity and to determine the origin (modality) of the recorded activity. A method using the autocorrelation function of recorded nerve activity and an artificial neural network was developed to classify the modality of nerve signals. The method works in cases where different end organs are innervated by nerve fibers having different diameter distributions. The electrical activity in the cat S1 sacral spinal root was recorded using a cuff electrode during the activation of cutaneous, bladder, and rectal mechanoreceptors. Using the classification method, 87.5% of nerve signals were correctly classified. This result demonstrates the effectiveness of the neural network classification method to determine the modality of the nerve activity arising from activation of different receptors.
Action Potentials↗
Computed tomographic images reflect the biologic behavior of small lung adenocarcinoma: they correlate with cell proliferation, microvascularization, cell adhesion, degradation of extracellular matrix, and K-ras mutation.
BACKGROUND: We previously reported that the computed tomographic M/L ratio (area of the tumor in the mediastinal computed tomographic image/area of the tumor in the lung computed tomographic image) of small peripheral lung adenocarcinoma is correlated with patient prognosis. METHODS: Immunostaining for p53, bcl-2, Ki-67, vascular endothelial growth factor, CD34, matrix metalloproteinase 2, matrix metalloproteinase 9, tissue inhibitor of matrix metalloproteinase 2, and mutation of K-ras was assessed in 131 surgically resected, primary peripheral lung adenocarcinomas of 30 mm or less in maximum diameter to clarify the relationship between computed tomographic findings and biologic activities. RESULTS: The numbers of patients with high labeling indexes of Ki-67 and high expression of vascular endothelial growth factor, CD34, matrix metalloproteinase 2, and matrix metalloproteinase 9 in the solid-type group (computed tomographic M/L ratio > or = 50%) were significantly higher than those in the faint density-type group (computed tomographic M/L ratio < 50%; P = .04 for Ki-67, P = .03 for vascular endothelial growth factor, P = .0009 for CD34, P = .001 for matrix metalloproteinase 2, and P = .00001 for matrix metalloproteinase 9). The number of patients with high levels of CD44v6 or tissue inhibitor of matrix metalloproteinase 2 staining in the faint density-type group was significantly higher than that in the solid-type group (P = .02 for CD44v6 and P = .01 for tissue inhibitor of matrix metalloproteinase 2). Independent variables capable of predicting computed tomographic M/L ratio included CD34, matrix metalloproteinase 2, matrix metalloproteinase 9, and tissue inhibitor of matrix metalloproteinase 2 (P = .0093, P = .0003, P = .0027, and P = .01, respectively; binary logistic regression analysis). CONCLUSIONS: Our results suggest that the computed tomographic image of small lung adenocarcinoma is correlated with biologic activities and thus provides possible prognostic information.
Adenocarcinoma↗
Peripheral binding mode and penetration depth of cobra cardiotoxin on phospholipid membranes as studied by a combined FTIR and computer simulation approach.
Cobra cardiotoxin, a cytotoxic beta-sheet basic polypeptide, is known to cause membrane leakage in many cells including human erythrocytes. Herein, we demonstrate that the major cobra cardiotoxin from Naja atra, CTX A3, can cause leakage of vesicle contents in phosphatidylglycerol (PG) and phosphatidylserine containing, but not in pure phosphatidylcholine (PC), membrane bilayers. By the combined polarized attenuated total reflection infrared spectroscopy and computer simulation studies, CTX A3 is shown to peripherally bind to both zwitterionic and anionic monolayers in a similar edgewise manner with a tilted angle of approximately 48 +/- 20 degrees between the beta-sheet plane of the CTX molecule and the normal of the membrane surface. The average surface area expansion induced by CTX A3 binding to the PG monolayer, however, is two times larger than that of the PC monolayer as determined by the Langmuir minitrough method. Interaction energy considerations of CTX A3 on neutral and negatively charged membrane surfaces suggests that the electrostatic interaction between anionic lipid and cationic CTXs plays a role in modulating the penetration depth of CTX molecules on the initial peripheral binding mode and reveals a pathway leading to the formation of an inserted mode in negatively charged membrane bilayers.
Animals↗
On the biologically active structures of cholecystokinin, little gastrin, and enkephalin in the gastrointestinal system.
The biologically active conformations of a series of four peptides [four cholecystokinin (CCK)-related peptides and enkephalin] in their interactions with gastrointestinal receptors have been deduced using conformational computational analysis. The two peptides that interact exclusively with peripheral-type CCK receptors are the heptapeptide COOH-terminal fragment from CCK (CCK-7) and the analogous sequence from cerulein (CER-7) in which threonine replaces the methionine proximal to the NH2 terminus. The two peptides that interact exclusively with the gastrin receptor in the stomach are the active COOH-terminal fragment of little gastrin and the COOH-terminal tetrapeptide sequence common to all of these peptides, CCK-4. We find that preferred conformations for the peripherally active peptides CCK-7 and CER-7 are principally beta-bends, whereas little gastrin and CCK-4 are fundamentally helical. In the class of lowest energy structures for both CCK-7 and CER-7, the aromatic rings of the tyrosine and phenylalanine lie close to one another whereas the tryptophan indole ring points in the opposite direction. This structure is superimposable on the structures of a set of rigid indolyl benzodiazepine derivatives that interact with complete specificity and high affinity with peripheral CCK receptors further suggesting that the computed beta-bends are the biologically active conformation. The biologically active conformation for CCK-4 and the little gastrin hexapeptide has also been deduced. By excluding conformations common to CCK-7 and CCK-4, which do not bond to each other's receptors, and then by selecting conformations in common to CCK-4 and the gastrin-related hexapeptide, which do bind to each other's receptors, we deduce that the biologically active conformation at the gastrin receptor is partly helical and one in which the indole of tryptophan and the aromatic ring of phenylalanine are close to one another while the methionine and aspartic acid side chains point in the opposite direction. These major differences in preferred structures between the common CCK-7/CER-7 peptides and the common CCK-4/little gastrin peptides explain the mutually exclusive activities of these two sets of peptides. We have observed that [Met]enkephalin strongly antagonizes the action of the naturally occurring peripherally active CCK-8 (CCK-7 with an NH2-terminal aspartic acid residue added). The computed lowest energy structures for this opiate peptide closely resemble key features of the computed CCK-7/CER-7 structure, further supporting the proposed structure.
Amino Acid Sequence↗
Computer assisted image analyses of corpora lutea in relation to peripheral concentrations of progesterone: a comparison between breeds of sheep with different ovulation rates.
Transrectal ovarian ultrasonography is a non-invasive technique that permits the real-time serial visualization of ovarian structures. Previous studies have reported correlations between serum progesterone concentrations and physical characteristics of the corpus luteum (CL) in different species. The aim of the present study was to investigate whether or not there were correlations between ultrasound image attributes of the CL and changing progesterone concentrations over time, in prolific and non-prolific ewes. Ultrasonographic images of CL were taken, once daily, from 12 Western White Face ewes and 7 Finn ewes for the duration of one luteal phase. Blood samples were collected daily prior to each scanning session and assayed to determine mean serum concentrations of progesterone. Analysis of ultrasound images was performed using a series of custom-developed computer algorithms optimized for ultrasonography on a computer graphics workstation. Both total luteal area and mean pixel values were correlated with the pattern of serum concentrations of progesterone from days 3 to 15 after ovulation in Western White Face ewes and from days 3 to 14 in Finn ewes. There was no significant correlation between progesterone concentrations and spot pixel heterogeneity for either Western White Face ewes or Finn ewes. We concluded that pixel heterogeneity is a poor indicator of progesterone secretory ability of the CL when compared to mean pixel values. However, luteal area and mean spot pixel values are better but not strong indicators of the functional status of the CL in cyclic ewes.
Algorithms↗