[Intravascular ultrasonography, a novel method in vascular imaging].
Explore the source record for details and available documents.
Coronary Angiography↗
Biomedical subjects
H Manninen
Publications and source records attributed to H Manninen.
1995 Volvo Award in clinical sciences. Determinants of lumbar disc degeneration. A study relating lifetime exposures and magnetic resonance imaging findings in identical twins.
STUDY DESIGN: Retrospective cohort. OBJECTIVES: To investigate the effects of lifetime exposure to commonly suspected risk factors on disc degeneration using magnetic resonance imaging, and to estimate the effects of these suspected risk factors relative to age and familial aggregation, reflecting genetic and shared environmental influences. SUMMARY OF BACKGROUND DATA: Structural and biochemical changes associated with disc degeneration are suspected as the underlying conditions of many back-related symptoms. Little is known about the determinants of disc degeneration. METHODS: Based on lifetime discordance in suspected environmental risk factors for disc degeneration, 115 male identical twin pairs were selected. An in-depth interview was conducted of occupational and leisure time physical loading, driving, and smoking. Disc degeneration was evaluated using observational and digital magnetic resonance imaging assessment methods. RESULTS: Heavier lifetime occupational and leisure physical loading was associated with greater disc degeneration in the upper lumbar levels (P = 0.055 - 0.001), whereas sedentary work was associated with lesser degeneration (P = 0.006). These univariate associations did not reach statistical significance in the lower lumbar region. In multivariate analyses of the upper lumbar levels, the mean job code explained 7% of the variability in observational disc degeneration scores; the addition of age explained 16%, and familial aggregation improved the model such that 77% of the variability was explained. In the lower lumbar levels, leisure time physical loading entered the multivariate model, explaining 2% of the variability. Adding age explained 9%, and familial aggregation raised the variability in disc degeneration scores explained to 43%. CONCLUSIONS: The present study findings suggest that disc degeneration may be explained primarily by genetic influences and by unidentified factors, which may include complex, unpredictable interactions. The particular environmental factors studied, which have been among those most widely suspected of accelerating disc degeneration, had very modest effects.
Adult↗
Observer variability in the assessment of disc degeneration on magnetic resonance images of the lumbar and thoracic spine.
STUDY DESIGN: Intraobserver and interobserver reproducibility study. OBJECTIVE: This study investigates the variability in the interpretation of degenerative disc findings using magnetic resonance imaging. SUMMARY OF BACKGROUND DATA: Magnetic resonance imaging has been used for years in clinical diagnostics, primarily to investigate disc herniation and spinal stenosis. Less attention has been paid to other disc findings and their assessment reliability. METHODS: Three independent readers evaluated magnetic resonance images of the lumbar and the lower and middle thoracic spines of 122 subjects by grading 12 aspects of the intervertebral discs and adjacent endplates using written definitions and example images. Images of 20 subjects were reevaluated for the assessment of intraobserver agreement. RESULTS: Agreement was highest in the lower lumbar and poorest in the middle thoracic spine. Intraobserver agreement was generally fair to excellent for almost all variables in the lumbar and lower thoracic spine (most intraclass correlation and kappa coefficients for these regions were above 0.70). Interobserver agreement was notably lower than intraobserver agreement, except for osteophytes and endplate defects in some regions. CONCLUSIONS: Intraobserver agreement in the evaluation of disc degeneration was at an acceptable level, in general, in the lumbar and lower thoracic spine. However, assessments were substantially more variable between readers, which limits comparisons of evaluations between different readers.
Adult↗
Magnetic resonance imaging findings and their relationships in the thoracic and lumbar spine. Insights into the etiopathogenesis of spinal degeneration.
STUDY DESIGN: Descriptive epidemiologic study about magnetic resonance imaging findings in the spine. OBJECTIVES: To describe the prevalence of magnetic resonance imaging findings in a general population at spinal levels T6-S1, and to examine the relationships of these findings within each spinal level and between levels. SUMMARY OF BACKGROUND DATA: The prevalence of specific findings and the associations between findings and spinal levels can provide general insights into the etiopathogenesis of spinal degeneration. METHODS: Subjects consisted of 232 men from a population sample (mean age 49.3 years). Signal intensity, disc bulging, disc herniation, and endplate irregularities were among 11 findings assessed from magnetic resonance images. RESULTS: The disc signal intensities were assessed to be lowest in the lumbar and middle thoracic regions. Disc bulging and disc height narrowing were most common in the lower levels of both the thoracic and lumbar regions. All magnetic resonance imaging findings except herniations and endplate irregularities were clearly associated with age. Osteophytes were most highly associated with disc bulging in levels T6-L3, and with endplate irregularities in the lower lumbar levels. Disc herniations were not consistently associated with any other findings. The disc levels that most highly correlated are grouped as follows: T6-T10, T10-L4, and L4-S1. CONCLUSIONS: With the exception of endplate irregularities and herniations, the magnetic resonance imaging findings appeared to be associated with the same pathogenic process. The interaction of mechanical factors and spinal structures varies between spinal levels, and the degeneration common in the lower parts of the thoracic and lumbar spine could be an outcome of vulnerability for torsional forces. Some gross guidelines for grouping findings can be drawn from disc level correlations.
Adult↗
Thoracic outlet syndrome--a functional disturbance of the thoracic upper aperture?
We describe a young woman with typical neurovascular symptoms of thoracic outlet syndrome (TOS). A three-dimensional computerized scan showed a "dislocation" of the first rib at the costotransverse joint. The patient responded to a conservative approach to treatment. The patient presented here demonstrates the functional compromise of the upper thoracic aperture that is frequently seen in young women.
Adult↗
Breathing pattern and gas exchange in emergency and elective abdominal surgical patients.
OBJECTIVE: To evaluate the effects of intra-abdominal surgical emergency on breathing pattern and gas exchange and compare it with the changes induced by elective abdominal surgery. DESIGN: Prospective clinical study. SETTING: Abdominal surgical departments in a university hospital. PATIENTS: Patients operated for intra-abdominal emergency (n = 10, EAS), elective upper abdominal (n = 19, UAS). MEASUREMENTS AND RESULTS: Breathing pattern and gas exchange were measured with a respiratory inductive plethysmograph and a gas exchange monitor. EAS patients had pre-operatively a classical rapid shallow breathing pattern and increased ventilatory demand due to increased energy expenditure. The operation improved the breathing to normal pattern (frequency, 26 +/- 5/min and 17 +/- 3/min, p < 0.01; tidal volume, 439 +/- 128 ml and 541 +/- 165 ml, NS., before and after surgery, respectively). Sighing was absent before and after EAS and strictly reduced after elective surgery (p < 0.01 for UAS). The operation restricted the abdominal-diaphragmatic breathing movement which was reflected as increased contribution of the rib cage to VT (%RC: from 37% +/- 15 to 57% +/- 15 for UAS p < 0.001; from 47% +/- 16 to 61% +/- 14 for EAS NS.). After EAS and UAS hypoxemia was common (p < 0.001) with frequent radiological pathology. We conclude that intra-abdominal surgical emergencies increase the ventilatory demand and challenge the respiratory system to marked adaptive changes both pre- and post-operatively.
Abdomen↗
Hemodynamic effects of carotid endarterectomy by magnetic resonance flow quantification.
BACKGROUND AND PURPOSE: Blood flow can be evaluated non-invasively using magnetic resonance phase-contrast flow quantification. The purpose of this prospective study was to assess the feasibility of this method and to evaluate the hemodynamic effects of carotid endarterectomy. METHODS: Volumetric flow rates and peak systolic velocities of the internal and common carotid and the vertebral arteries were measured by magnetic resonance flow quantification. Sixteen patients undergoing 18 endarterectomies had complete flow data recorded preoperatively and 3 days after surgery. RESULTS: The inverse correlation between the angiographic stenosis degree and the preoperative flow rate in the corresponding internal carotid artery was highly significant (r = -.69, P < .001). After endarterectomy, the mean flow in the ipsilateral internal carotid artery improved from 143 to 233 mL/min (P < .001). The mean peak systolic velocity increased from 23 to 37 cm/s (P < .001). No significant changes were seen in the contralateral carotid or the vertebral arteries. The mean total blood flow improved by 81 mL/min (P = .08). In the severely stenosed bifurcations (70% to 99%, n = 11), the flow rate improved by 106 mL/min and in the moderately (30% to 69%, n = 4) or mildly (< 30%, n = 3) stenosed bifurcations by 63 mL/min. If the contralateral carotid artery was occluded or severely stenosed, the improvement was 164 mL/min. CONCLUSIONS: Magnetic resonance flow quantification provides a useful tool for the follow-up of the hemodynamic effects of carotid endarterectomy. Our results indicate that surgery is followed by a significant increase of blood flow in the ipsilateral carotid artery and that there appear to be differences in flow increase between subgroups of patients with different degrees of stenosis.
Aged↗
Carbon dioxide in vascular imaging and intervention.
Angiography with iodinated contrast agents is bound up with the risks of contrast-induced nephrotoxicity and hypersensitivity, which led to the idea of using carbon dioxide (CO2) gas as a negative contrast medium to eliminate these drawbacks. During the last decade, refinements and experiences have proved carbon dioxide digital subtraction angiography (CO2-DSA) to be an accurate, safe, and clinically promising vascular imaging modality, with the advantages of no hypersensitivity and no nephrotoxicity as well as minimal patient discomfort. In this article, we have reviewed the history, physical and chemical aspects, techniques, and pathophysiologic changes with the use of CO2-DSA as well as some clinical trials. Applications of CO2 gas in vascular interventions and other imagings, and the advantages and limitations of using CO2 gas in DSA are also discussed.
Angiography↗
Imaging of carotid artery stenosis: clinical efficacy and cost-effectiveness.
PURPOSE: To determine the most accurate, safe, and cost-effective imaging protocol for selecting patients for carotid endarterectomy. METHODS: The actual costs of carotid angiography, ultrasound, and MR angiography were calculated. The diagnostic accuracy with different confidence levels was assessed for carotid ultrasound and MR angiography in 45 patients. The cost-effectiveness and theoretical impact on patient outcome of hypothetical screening models were compared. RESULTS: Ultrasound before angiography is more effective and considerably cheaper than performing angiography in all patients presenting with transient ischemic attacks ($25 216 versus $48 708 imaging costs per one prevented stroke). When the more costly MR angiography was used to select patients for angiography the slightly higher diagnostic accuracy did not result in a greater number of prevented strokes. As the only preoperative scrutiny, the combination of ultrasound and MR angiography would have resulted in a greater number of prevented strokes than invasive angiography (27.9 versus 23.3) but at the expense of unnecessary surgery (6.6% of all surgeries). CONCLUSIONS: Ultrasound followed by confirmatory angiography is a cost-effective way to image patients suspected of carotid artery stenosis. MR angiography may become cost effective and lead to a better final patient outcome only when it can reliably replace invasive angiography as the preoperative examination.
Angiography, Digital Subtraction↗
Predictors of conduction disturbances after coronary bypass grafting.
One hundred sixty-nine patients undergoing coronary artery bypass grafting were included in a prospective study to test the effect of coronary pathology on conduction disturbances (CD). At the same time, several other proposed preoperative and intraoperative predictors of CD were collected. From the angiograms, the vascularization of the interventricular septum was classified according to Mosseri and colleagues. Ninety-four patients (56%) had type II coronary pathology, which does not allow full revascularization of the interventricular septum. The tested classification did correlate with the state of coronary disease, resulting in more left main coronary stenoses and more numerous peripheral anastomoses in type II patients. However, there was no correlation between the classification and CD. Patients with permanent CD (34%) had more left main coronary artery stenoses (29% versus 14%; p = 0.03). Their measured maximal myocardial temperatures were lower in all three myocardial regions measured (p = 0.01 to 0.07), and their creatine kinase MB fraction values on the day of operation were also higher (92 versus 70 IU; p = 0.002). In multivariate logistic regression analysis, the maximal temperature of the left circumflex artery region and the presence of left main coronary artery stenoses were the only independent predictors of permanent CD. We conclude that excessively low myocardial temperatures during cardioplegia may cause CD.
Adult↗
Sidebending versus flexion-extension radiographs in lumbar spinal instability.
Flexion-extension radiography is accepted as an effective method for the diagnosis of lumbar spinal instability, but the usefulness of sidebending films is less well known. Flexion-extension and sidebending radiographs of 300 patients with clinically suspected lumbar spinal instability were analyzed retrospectively. Generally used criteria for lumbar spine instability were applied in the film analysis. Although flexion-extension and sidebending films were statistically significantly interrelated in the diagnosis of instability, intertechnique agreement remained poor. Flexion-extension films more frequently revealed signs of instability than sidebending films; 84 vs 50 patients. Signs of instability on sidebending films showed the best correlation with the findings of angular motion and posterior sliding instability on flexion-extension films. Sidebending films are complementary to flexion-extension films but are unlikely to be helpful on a routine basis.
Adolescent↗
Comparison of angiographic opacification of ioxaglate and iodixanol by digital region-of-interest processing technique in an experimental circulation model.
RATIONALE AND OBJECTIVES: By using digital ROI (region of interest) processing techniques, we measured and compared directly the angiographic opacification of ioxaglate and iodixanol in an experimental circulation model. METHODS: A pulsatile pump circulated water into a 2-mm plastic tube for digital subtraction angiography (DSA). Altogether, 90 digital imaging series were registered during injections of two contrast media with 320, 300, and 270 mg/mL iodine concentrations. By selecting a "vessel" ROI and a subtracted background ROI, a time-density curve (TDC) was created. From the TDC, the average density of contrast media and the appearance time of contrast media into the selected ROI were measured. RESULTS: The average density was statistically different (P < .01) among three various iodine concentrations of the contrast media, but no difference was found between the two contrast media. The appearance times of ioxaglate with 320 mg/mL iodine concentration were statistically shorter (P < .01) than those of iodixanol. In both contrast medium groups, the appearance times were statistically shorter (P < .05) with 270 mg/mL iodine concentration than with two higher iodine concentrations. CONCLUSION: The current experimental set-up facilitates reproducible measurement of angiographic opacification during the injection of contrast media. The average densities between ioxaglate and iodixanol are the same, but are significantly different among three iodine concentrations. The different appearance times of the two CM and the three iodine concentrations may be caused by the various viscosities of the contrast media.
Angiography, Digital Subtraction↗
Influence of carbon dioxide gas perfusion to thermal distribution of sapphire probe. A comparative study with saline.
RATIONALE AND OBJECTIVES: A previous study confirmed that the direct laser-thermal conduction of the sapphire probe with carbon dioxide gas perfusion increased the width of the laser-recanalized channel. This caused us to further investigate the thermal distribution characteristics of the sapphire probe when lasing with CO2 gas perfusion. METHODS: The surface temperature of a sapphire probe in a circulation model using 37 degrees C flowing whole blood was measured. Two hundred and sixteen measurements were obtained by directly contacting a flexible thermocouple wire onto the sapphire probe at different sites: 1) metal connector; 2) lateral side of the sapphire crystal; 3) top of the sapphire crystal; and 4) 3 mm in front of the sapphire probe. During lasing with a neodymium-yttrium-aluminum garnet (Nd-YAG) laser, the CO2 gas or saline was infused through the sapphire probe at different flow rates. RESULTS: The lateral side of the sapphire crystal was heated up to 75 degrees C when lasing without any perfusion, but up to 220 degrees C when lasing with CO2 gas perfusion. At all four sites, the mean temperature increases were statistically higher (P < .01) with CO2 gas than with saline perfusion. The mean peak temperatures increased with increasing flows of CO2 gas perfusion and decreased with increasing flows of saline perfusion. CONCLUSIONS: The thermal conduction from the sapphire probe can be significantly enhanced by increasing flows of CO2 gas perfusion. This may play an important role in creating a greater diameter of the recanalized channel and in better delaying the formation of restenosis or re-occlusion after laser recanalization of atheromatous arteries.
Aluminum Oxide↗
The best method to quantitate angiographic carotid artery stenosis?
Explore the source record for details and available documents.
Carotid Stenosis↗
Carotid stenosis by digital subtraction angiography: reproducibility of the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial measurement methods and visual interpretation.
PURPOSE: To evaluate different carotid stenosis estimation methods with digital subtraction angiography. METHODS: We assessed the intraobserver reproducibilty and interobserver variability of visual interpretation and the measurement methods used by the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial. Angiographic stenosis measurements according to both criteria were performed twice by a radiologist, a neurologist, and a vascular surgeon. Eighty bifurcations of consecutive symptomatic patients underwent 480 pairs of measurements. In addition, four radiologists estimated the stenoses visually. RESULTS: Intraobserver consistency was slightly better by the European (kappa, 0.86 to 0.94) than by the North American (kappa, 0.68 to 0.91) trial criteria or by visual interpretation (kappa, 0.79 to 0.81). No significant interobserver variability was found, except in the subgroup of mild stenoses by the North American Trial criteria. By kappa statistic, the interobserver agreement was excellent by the European trial method (kappa, 0.72 to 0.86), good by the North American trial method (kappa, 0.59 to 0.77), and good to excellent by visual evaluation (kappa, 0.68 to 0.88). The visual estimation agreed more closely with the European (kappa, 0.73 to 0.92) than with the North American trial (kappa, 0.55 to 0.74) criteria measurements. CONCLUSIONS: All three methods have good reproducibility in digital subtraction angiography. Interobserver differences become more important in the estimation of mild stenosis.
Adult↗
Accuracy of digital videodensitometry in quantitating contrast medium concentration.
To evaluate the accuracy of digital videodensitometric technique in directly quantitating concentration of contrast medium, iohexol 300 mg I/ml was injected into a 2-mm-diameter plastic tube, in which clean water was circulated at a 190 ml/min flow, for digital subtraction angiography. Altogether 27 injections were performed with 3, 4 and 5 ml volumes at 3-, 4- and 5-ml/s flows of the contrast medium. A time-density curve was achieved by selecting a "vessel" region of interest (ROI) and a background ROI. Then, a frame corresponding to the maximum opacification of the contrast medium could be calculated. Finally, the average density and the time to peak density of the contrast medium were obtained. The average density was statistically higher (p < 0.01) with 5 ml/s flow than with 4- and 3-ml/s flows. Times to peak density reduced as injection flows or volumes increased. The results support the conclusion that digital videodensitometric technique is an accurate method for quantitation of contrast medium concentration during angiography. The angiographic opacification may be improved by injecting the iodine contrast medium with higher flows or larger volumes.
Absorptiometry, Photon↗
Asymptomatic deep venous thrombosis in the calf: accuracy and limitations of ultrasonography as a screening test after total knee arthroplasty.
Patients who have recently undergone total knee arthroplasty are at high risk of developing deep venous thrombosis (DVT) in the calf. The clinical diagnosis of DVT is difficult in these patients owing to recent operation. A combination of compression ultrasonography (US) and colour flow imaging was used as a screening method of asymptomatic DVT in 51 patients who had undergone total knee replacement surgery. Both limbs were examined by US from the common femoral vein to the ankle approximately 7 days after operation and the results were compared with bilateral venography. 12 patients (24%) developed infrapopliteal DVT on the operated side, in two cases the thrombosis extended to the lower part of popliteal vein. One patient had bilateral thrombosis. US showed sensitivity of 77%, specificity of 96% and overall accuracy of 93%. US seems to be a useful screening method for DVT after knee replacement operation.
Aged↗
Exercise therapy effects on functional radiographic findings and segmental electromyographic activity in lumbar spine instability.
Flexion-extension and traction-compression radiographs as well as functional electromyographic (EMG) analysis were used to assess nine patients with chronic low back pain and segmental instability symptoms. After a treatment program, at which time most of the patients were asymptomatic and their physical status normalized, the patients were reexamined using EMG and radiographs. No significant change was found in the functional radiographic examination, whereas the myographic findings were significantly improved. Although the number of subjects was small, the results suggest that radiographic findings correlate poorly with clinical findings. Because of the improvement of the physical and myographic findings, the term "segmental dysfunction" may better describe the disability and symptoms than does the term "segmental instability."
Adult↗