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S Soimakallio

Publications and source records attributed to S Soimakallio.

At least 19 recordsLinked to original sources
PubMed1995

Radiation-induced changes in human brain metabolites as studied by 1H nuclear magnetic resonance spectroscopy in vivo.

PURPOSE: External radiation therapy for brain tumors exposes healthy areas of brain to considerable doses of radiation. This may cause cognitive and psychological impairment, which indicate neuronal dysfunction. 1H-magnetic resonance spectroscopy (MRS) was used to study brain metabolites in the adjacent regions 0.5-13 years after exposure to therapeutic irradiation. METHODS AND MATERIALS: Eight patients with irradiated brain tumors were examined by means of in vivo 1H-MRS using a point-resolved spectroscopy (PRESS) sequence with echo times of 60 or 270 ms. The metabolites were quantified by using brain water concentration as internal reference. The volume of interest (VOI) was positioned in irradiated brain areas excluding, however, scar and recurrent tumor. The respective radiation doses were measured based on radiation therapy plans, simulator films, and localization MR images. RESULTS: The concentration of the neuron-specific metabolite N-acetyl-L-aspartate (NAA) was 13.2 +/- 1.4 mmol/l in controls, whereas it was reduced in the brains of treated patients to 8.6 +/- 0.9 mmol/l (total radiation dose 59-62 Gy). Concentrations of creatine and choline-containing compounds were unchanged. The T2 of water was longer in irradiated than in unexposed brain areas. CONCLUSION: Therapeutic brain irradiation causes neuronal damage, which is reflected by reduction of N-acetyl-L-aspartate (NAA) concentrations. 1H-MRS could serve clinically as a means of evaluating adverse effects in the central nervous system, enabling intervention and rehabilitation.

Adult↗
PubMed1995

Carotid artery stenosis: clinical efficacy of MR phase-contrast flow quantification as an adjunct to MR angiography.

PURPOSE: To assess the utility of magnetic resonance (MR) flow quantification in the evaluation of suspected carotid artery stenosis. MATERIALS AND METHODS: Fifty-five patients referred for angiography and 10 healthy volunteers underwent Doppler ultrasound, three-dimensional time-of-flight MR angiography, and MR phase-contrast flow quantification to measure peak systolic velocity (PSV) and volumetric flow rate (VFR) in the common and internal carotid arteries distal to the stenosis. RESULTS: PSV and VFR were significantly lower in the severely (> or = 70%) stenosed internal carotid arteries (P < .05). The VFR ratio (internal carotid artery-common carotid artery) achieved 91% overall accuracy for detection of severe stenosis. Combination of flow data with results of MR angiography yielded sensitivity of 100% (95% confidence interval, 78%-100%) with a modest loss in specificity. Doppler and MR measurements of PSV in the common carotid artery showed significant correlation: volunteers, r = .73; patients, r = .64. CONCLUSION: MR flow quantification provides information about the hemodynamic significance of carotid stenosis. As an adjunct to MR angiography, it may be useful in enabling differentiation of occlusions from critical stenoses.

Adult↗
PubMed1995

Rotator cuff calcifications: treatment with US-guided technique.

PURPOSE: The authors developed and tested a technique to treat calcific tendinitis in the rotator cuff with multiple needle punctures, aspiration, and lavage under ultrasonographic (US) guidance. MATERIALS AND METHODS: Atraumatic pain in the shoulders of a 46-year-old woman and a 42-year-old man was resistant to conservative therapy. With local anesthesia and continuous three-dimensional US visualization, the tips of two 18-gauge needles were placed within the calcification in the rotator cuff. Saline solution was injected and aspirated with the needles until the aspirate was free of calcific particles. RESULTS: Both patients experienced complete relief of pain and recovery of full range of motion, one on the 3rd day after treatment and one within 15 minutes. CONCLUSION: Use of this US-guided technique is successful to treat calcific tendinitis in the rotator cuff without the radiation exposure of fluoroscopic guidance.

Adult↗
PubMed1995

Medial displacement of the biceps brachii tendon: evaluation with dynamic sonography during maximal external shoulder rotation.

PURPOSE: To determine the value of the sonographic subluxation test--dynamic scanning of a shoulder during maximal external rotation--in the evaluation of medial displacement of the biceps tendon. MATERIALS AND METHODS: The subluxation test was performed during shoulder sonography in 1,210 patients, 284 of whom subsequently underwent surgery (152 men and 132 women aged 24-77 years [mean, 52 years]). Subluxation or displacement of the biceps tendon was surgically confirmed in 21 of the 284 patients (16 men and five women aged 35-57 years [mean, 48 years]). The sonographic and surgical findings in these 21 patients were analyzed. RESULTS: The subluxation test helped detect 12 of 14 (86%) cases of subluxation. Static scanning (without the subluxation test) depicted six of seven (86%) cases of dislocation. The test failed or could not be performed in 18 of the 284 (6%) patients; however, no false-positive findings occurred. CONCLUSION: The subluxation test is reliable in the diagnosis of subluxation of the biceps tendon and should be performed during shoulder sonography.

Adult↗
PubMed1995

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↗
PubMed1995

Defecography.

Defecography, a dynamic imaging modality, plays an important role in the diagnosis of functional and morphologic abnormalities of the anorectal region. We have here summarized the principle and techniques as well as observations of defecography, with special emphasis on morphologic measurements, clinical relevance, and limitations. The application of MR imaging in examination of anorectal function has also been addressed.

Barium Sulfate↗
PubMed1994

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↗
PubMed1994

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↗
PubMed1994

Femoropopliteal angioplasty in patients with claudication: primary and secondary patency in 140 limbs with 1-3-year follow-up.

PURPOSE: To determine the usefulness of percutaneous transluminal angioplasty in the femoropopliteal arteries in patients with claudication. MATERIALS AND METHODS: In a prospective study of 106 claudicants (71 men and 35 women, aged 41-90 years [mean, 67 years]), a total of 208 lesions in 140 limbs were treated. The patients were followed up for 12-36 months. The patency rates were based on determination of the ankle-brachial index. RESULTS: The hemodynamic success rate for all the treated limbs was 89%, 99% for femoropopliteal stenoses (n = 71) and 80% for femoropopliteal occlusions (n = 69). In multiple logistic regression analysis, a smaller number of diseased vessels (one to two vs three to seven) and milder lesion severity (stenosis vs occlusion) correlated favorably with early success. Survival analysis with the Kaplan-Meier method according to established criteria revealed 1-, 2-, and 3-year primary patency rates of 47% (27 of 57 limbs), 41% (14 of 34 limbs), and 43% (three of seven limbs), respectively. CONCLUSION: In selected cases, good primary success and acceptable long-term results can be achieved with femoropopliteal angioplasty in claudicants.

Adult↗
PubMed1994

Prophylaxis for the prevention of venous thromboembolism after total knee arthroplasty. A comparison between unfractionated and low-molecular-weight heparin.

We compared the efficacy and safety of low-molecular-weight heparin with that of low-dose unfractionated heparin in the prevention of venous thromboembolism after total knee arthroplasty in a prospective, randomized, multicenter trial. One hundred and eighty-five patients were randomly assigned to two groups: ninety-two received low-molecular-weight heparin (forty milligrams of enoxaparin the evening before the operation and once a day subsequently) and ninety-three received unfractionated heparin (5000 international units the evening before the operation and three times a day thereafter). The prophylaxis was continued until bilateral ascending venography was performed six to nine days after the operation or, if venography was not done, until the eighth postoperative day. Venography revealed a prevalence of deep-vein thrombosis of 27 per cent (twenty-five of ninety-three patients) in the group that received unfractionated heparin and 23 per cent (twenty-one of ninety-two patients) in the group that received low-molecular-weight heparin. The difference was not significant (p = 0.6). Five patients (5 per cent) who received unfractionated heparin and 3 patients (3 per cent) who received low-molecular-weight heparin had a deep-vein thrombosis in the proximal veins. Two patients who received unfractionated heparin and one who received low-molecular-weight heparin had clinical symptoms suggestive of a pulmonary embolism. None of these three patients had a positive ventilation-perfusion scan. There were no deaths, major bleeding episodes, or wound hematomas necessitating operative intervention or discontinuation of the anticoagulation in the series.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

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↗
PubMed1992

Endurance training associated with slightly lowered serum estradiol levels decreases mineral density of canine skeleton.

The effects of long-term running exercise were studied in 20 beagle dogs. A total of 10 dogs ran from the age of 15 weeks to the age of 70 weeks in a progressive program for up to 40 km/day. A total of 10 sister dogs spent the study period in individual cages. When the dogs were 70 weeks old, bone mineral density of the vertebrae, hip, and radius was analyzed by dual-energy x-ray absorptiometry (DEXA; Lunar) and the vertebrae were also assessed by quantitative computed tomography (QCT; Siemens DR 1). Mineral density was lower in the running dogs than in the controls. The difference was greatest in the spine in the QCT analysis. Blood chemistry analyses revealed that the metabolism of the bone was significantly accelerated. The estradiol levels showed the trend to be reduced in the running group. The beneficial effect of exercise on mineral density has been shown in many earlier studies. However, in this study we demonstrate the possibility of adverse effects of long-term exercise on bone tissue. The change was associated with a decrease of serum estradiol level.

Alkaline Phosphatase↗
PubMed1991

Effects of long-term running on spinal mineral content in dogs.

The effects of long-term running were studied in 20 beagle dogs. Ten dogs ran from the age of 15 weeks to the age of 70 weeks in a progressive program for up to 40 km/day. Ten sister dogs spent the same time in individual cages. At the age of 70 weeks the spines of the dogs were studied with regard to mineral density using dual-energy X-ray absorptiometry and quantitative computed tomography. Mineral density was lower in the running dogs than in the controls.

Animals↗