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S Savolainen

Publications and source records attributed to S Savolainen.

At least 73 records · Page 4Linked to original sources
PubMed1995

Segmentation methods for volume determination with 111In/99Tcm SPET.

Objective determination of regions of interest (ROIs) is a prerequisite for the accurate quantification of radionuclide volume distributions in single photon emission tomographic (SPET) images. In this study, we compared four segmentation methods: fixed thresholding (FT), grey level histogram (GL), region growing (RG) and combined region growing and edge detection (RGE). For this purpose, an elliptical phantom containing two cylinders with varying volumes (8-360 ml) and activities of 111In and 99Tcm (2.9-37 kBq ml-1) was employed. Using these methods, the following correlation was observed between true and measured phantom volumes: 111In, r = 0.95 (FT), 0.73 (GL), 0.93 (RG) and 0.92 (RGE); 99Tcm, r = 0.85 (FT), 0.72 (GL), 0.85 (RG) and 0.89 (RGE). Volume determination with FT and RG was not sensitive to the cut-off frequency used in image filtering. A significant correlation was observed between spleen volumes measured with the different segmentation methods, except GL, when applied to the SPET images of 25 patients administered 111In-labelled platelets. On the basis of these results, FT and RG are recommended for the clinical determination of ROIs, although they can be difficult to apply if the signal-to-noise ratio is very low or highly variable, when a combination of different imaging modalities may be the only accurate solution to the segmentation problem. The RGE method can also produce accurate results, but estimation of parameters is laborious with this method. Before being applied clinically, all segmentation methods tested in this study require phantom measurements for the determination of optimal parameters.

Humans↗
PubMed1995

Treatment of acute maxillary sinusitis--comparing cefpodoxime proxetil with amoxicillin.

In order to evaluate the clinical efficacy and tolerance of cefpodoxime proxetil, compared with that of amoxicillin in the treatment of acute bacterial maxillary sinusitis, a randomized, double-blind, parallel group comparative study was performed. A total of 286 adults patients were included at 12 centres, each treatment group consisting of 143 patients. Each patient was treated for 10 days and observed before and after treatment. The observations included clinical, roentgenological, bacteriological and laboratory examinations. At inclusion, the most common pathogens were Haemophilus influenzae (24%) and Streptococcus pneumoniae (17%). In the per protocol analysis, 117 patients in the cefpodoxime group and 113 in the amoxicillin group were evaluable for clinical efficacy. The clinical response rates were 96% and 91%, respectively. The corresponding figures in the intent-to-treat analysis were 130 and 128 patients, with clinical response rates of 93% and 88%, respectively. Cefpodoxime proxetil proved clinically as effective as amoxicillin in the treatment of acute bacterial maxillary sinusitis. It was more effective in eradicating H. influenzae and was more efficient in improving the radiological score. Adverse events were reported in 20% of cefpodoxime cases and in 16% of amoxicillin cases. There was no statistically significant difference between the groups.

Acute Disease↗
PubMed1994

Antimyosin scintigraphy in patients with acquired and hereditary muscular disorders.

Scintigraphy with indium-111 labelled antimyosin has an established role in the evaluation of cardiac muscle damage. This antibody has been shown to cross-react with myosin in skeletal muscle. We therefore studied the usefulness of this method for the detection of skeletal muscle lesions in rhabdomyolysis, myositis and hereditary muscular dystrophies. All nine patients with rhabdomyolysis had focal uptake of antimyosin antibody which correlated with the clinical findings of soft tissue damage. However, a number of symptomless lesions were also detected by immunoscintigraphy. In rhabdomyolysis the target to non-target uptake ratios varied from 1.3 to 7.6. Diffuse uptake of antibody in skeletal muscle was observed in all three patients with polymyositis-dermatomyositis and in 12 out of 13 patients with muscular dystrophies. In myositis the intensity of antibody accumulation correlated reasonably well with the magnitude of oedema detected by magnetic resonance imaging (MRI). Most patients with Becker type or non-X-chromosomal muscular dystrophies showed slight or moderate uptake of antibody, mainly in the lower extremities. In these patients more antibody accumulated in the calves than in the thighs, whereas the findings on MRI were more prominent in the thighs than in the calves, presumably because of the better preserved muscle bulk in the calves. We conclude that antimyosin scintigraphy can be used for the detection of muscle lesions not only in acquired muscle diseases but also in hereditary muscular disorders, and that immunoscintigraphy provides information on muscle disease activity not obtainable with MRI.

Adult↗
PubMed1994

Iliac crest versus artificial bone grafts in 250 cervical fusions.

Autologous (149 patients) and heterologous (101 patients) bone grafts were used for fusion in 250 patients with anterior cervical surgery. A stable fusion was achieved in 98% of patients in both groups and there was no significant difference in the clinical outcome. Donor site complications (severe pain, haematoma) were seen in one sixth of the patients with autologous bone grafts. If a fusion for anterior cervical surgery is necessary, the use of a heterologous bone graft should be preferred.

Bone Transplantation↗
PubMed1994

191Os/191mIr-generator for studying arterial blood flow in experimental animal models.

Iridium-191m (191mIr, t1/2 = 4.96 sec), an ultra-short lived tracer, has turned out to be suitable for gamma imaging. It can be obtained in high yields from an 191Os/191mIr-generator with a low 191Os breakthrough. In this study the blood flow in the carotid and kidney arteries was studied in rabbits by radionuclide arteriograms. In addition, the whole body retention and biodistribution of 191Os was studied in rats. 191mIr was obtained from an activated carbon system, in a modification of the procedure described in the literature. The kidney regions (study I) of rabbits were imaged dynamically (5 frames/second) for up to 40 seconds, and the investigations were repeated 4-7 times in the same animal. Similarly, the carotid arteries were studied (study II) and from the curves flow parameters were calculated. In order to study the 191Os breakthrough two groups of rats (n = 5) were sacrificed one day and four days after injecting five diagnostic doses into the tail vein (study III). In study III the Os-retention was highest in the kidneys and spleen, followed by the muscles and liver: 0.11-0.12% ID/g tissues were obtained at 1 day and 0.10-0.13% ID/g at 4 days, respectively. These values indicate that the breakthrough values are by no means toxic and that investigations can be repeated immediately with a negligible radiation exposure. The investigations performed with the same animals (I-II) could be easily repeated and were reproducible. All of this indicates that 191mIr is suitable for radionuclide angiography and the generator system is simple and safe to use (191Os is beta-emitter).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Peritonsillar abscess. Clinical and microbiologic aspects and treatment regimens.

This prospective study shows that acute peritonsillar abscess can be successfully treated by three-point puncture and aspiration. The results (recurrence in 19%) are comparable with published data on drainage of the peritonsillar space through the incision procedure. By proper selection of patients, the rate of recurrences can be further reduced. Because the occurrence of Streptococcus pyogenes in the aspirate seems to be associated with a favorable prognosis of therapy with puncture and antibiotics only, testing for the presence of this bacterial species might give a useful clue to the type of treatment needed. If the bacterial culture shows mixed aerobic and anaerobic flora, but not S pyogenes, and if the patient has a history of recurrent tonsillitis, incision or proceeding directly to tonsillectomy may be the best therapeutical choice.

Adolescent↗
PubMed1993

Validation of quantitative brain dopamine D2 receptor imaging with a conventional single-head SPET camera.

Phantom measurements were performed with a conventional single-head single-photon emission tomography (SPET) camera in order to validate the relevance of the basal ganglia/frontal cortex iodine-123 iodobenzamide (IBZM) uptake ratios measured in patients. Inside a cylindrical phantom (diameter 22 cm), two cylinders with a diameter of 3.3 cm were inserted. The activity concentrations of the cylinders ranged from 6.0 to 22.6 kBq/ml and the cylinder/background activity ratios varied from 1.4 to 3.8. From reconstructed SPET images the cylinder/background activity ratios were calculated using three different regions of interest (ROIs). A linear relationship between the measured activity ratio and the true activity ratio was obtained. In patient studies, basal ganglia/frontal cortex IBZM uptake ratios determined from the reconstructed slices using attenuation correction prior to reconstruction were 1.30 +/- 0.03 in idiopathic Parkinson's disease (n = 9), 1.33 +/- 0.09 in infantile and juvenile neuronal ceroid lipofuscinosis (n = 7) and 1.34 +/- 0.05 in narcolepsy (n = 8). Patients with Huntington's disease had significantly lower ratios (1.09 +/- 0.04, n = 5). The corrected basal ganglia/frontal cortex ratios, determined using linear regression, were about 80% higher. The use of dural-window scatter correction increased the measured ratios by about 10%. Although comprehensive correction methods can further improve the resolution in SPET images, the resolution of the SPET system used by us (1.5-2 cm) will determine what is achievable in basal ganglia D2 receptor imaging.

Brain↗
PubMed1993

Bacteriologic findings in peritonsillar abscesses in young adults.

Aspirated pus samples from 124 patients with peritonsillar abscess were cultured quantitatively for aerobes and anaerobes. A total of 98% of the samples yielded bacteria. Of the 550 isolates obtained (mean, 4.4 per patient), 143 were aerobes (representing 16 species or groups) and 407 were anaerobes (representing 40 species or groups). Aerobes were isolated from 86% of patients-alone in 20 cases and together with anaerobes in 87. The most common aerobic isolates were Streptococcus pyogenes (isolated from 45% of patients), Streptococcus milleri group organisms (27%), Haemophilus influenzae (11%), and viridans streptococci (11%). Anaerobes were isolated from 82% of the samples and as a sole finding from 15 abscesses. Fusobacterium necrophorum and Prevotella melaninogenica were both isolated from 38% of patients, Prevotella intermedia from 32%, Peptostreptococcus micros from 27%, Fusobacterium nucleatum from 26%, and Actinomyces odontolyticus from 23%. The rate of previous tonsillar/peritonsillar infections was lowest (25%) among patients infected with S. pyogenes and highest (52%) among those infected with F. necrophorum (P < .01). Recurrences and/or related tonsillectomies were more common among patients infected with F. necrophorum than among those infected with S. pyogenes (57% vs. 19%; P < .0001) or with S. milleri group organisms (43% vs. 19%; P < .05). beta-Lactamase was produced by only 38% of the 73 isolates of Prevotella species tested; however, 56% of the 36 patients studied harbored one or more such strains.

Adolescent↗
PubMed1992

SPECT versus planar scintigraphy for quantification of splenic sequestration of 111In-labelled platelets.

The splenic uptake of thrombocytes and spleen size were studied in 25 patients with idiopathic thrombocytopenic purpura (ITP) using two methods: anterior/posterior scintigraphy and single photon emission computed tomography (SPECT). Various factors (acquisition and reconstruction protocols) influencing the quality of 111In SPECT were studied. The splenic uptake, measured by SPECT, was found to be significantly higher in patients with a high level of autoantibodies in the blood than in patients without such antibodies (37 +/- 6%, n = 8 vs 22 +/- 3%, n = 11, P = 0.04, t-test). The correlation between the spleen SPECT volume and the geometric mean size in anterior and posterior images was 0.80 (P < 0.001). However, the spleen size calculated as geometric mean of anterior and posterior images differed by more than 50% from the SPECT volume in some patients. Based on these observations and on the results of phantom studies it is concluded that a reasonable estimate of the spleen:liver uptake ratio may be obtained using planar imaging, but to estimate the spleen volume and the absolute splenic uptake of platelets SPECT imaging is needed, in spite of the present technical limitations of SPECT.

Blood Platelets↗
PubMed1992

Platelet splenic transit times in idiopathic thrombocytopenic purpura. Compartmental vs. non-compartmental model.

Platelet splenic transit times following injection of autologous or homologous 111In-labeled platelets were studied in 42 patients with idiopathic thrombocytopenic purpura. The transit times were determined by two methods from the splenic time-activity curves recorded with a gamma camera: closed two-compartmental model and non-compartmental model (deconvolution analysis). By compartmental analysis the mean splenic transit time for platelets was 6.3 +/- 0.3 min (mean +/- S.E.) and by non-compartmental analysis 7.6 +/- 0.4 min for all cases studied. The mean splenic transit time for autologous platelets was significantly (p less than 0.001) shorter (5.1 +/- 0.3 min) in patients with platelet-associated IgG (measured by platelet suspension immunofluorescence test) than in those with no autoantibodies (7.1 +/- 0.4 min), when the compartmental model was employed. There was no significant difference between mean transit times for autologous platelets in antibody positive and negative patients when deconvolution analysis was applied, but the residue of the splenic transfer function was lower for antibody positive than negative patients (7.2 +/- 1.0% vs. 11.7 +/- 1.6%, p less than 0.05). It is concluded that in idiopathic thrombocytopenic purpura the presence of platelet-associated autoantibodies expands the splenic platelet pool and reduces recirculation of platelets.

Adolescent↗
PubMed1991

The comparative efficacy and safety of clarithromycin and amoxycillin in the treatment of outpatients with acute maxillary sinusitis.

The efficacy and safety of clarithromycin and amoxycillin in the treatment of acute maxillary sinusitis were compared in a single-blind, multicentre outpatient study. Fifty patients were randomly assigned to receive either clarithromycin 500 mg 12-hourly or amoxycillin 500 mg 8-hourly orally. Clinical signs and symptoms, sinus culture and blood and urine laboratory profiles were assessed prior to treatment, at four to six days during treatment, and within 48 h of the end of therapy (usually 9-11 days). Patients from whom beta-lactamase producing strains were isolated were excluded from the study. Both antibiotics achieved a clinical success rate of 91% within 48 h post-treatment; radiological resolution or improvement was observed in 91% of patients treated with clarithromycin and 89% of patients who received amoxycillin. Bacteriological cure was achieved in 88% and 91% of evaluable patients for clarithromycin and amoxycillin, respectively. Adverse events were reported for 16% of patients in the clarithromycin group compared to 26% in the amoxycillin group. Gastrointestinal disturbance was the most commonly occurring adverse event in both groups. The results of this study suggest that clarithromycin is as effective and well tolerated as amoxycillin in the treatment of acute maxillary sinusitis.

Acute Disease↗
PubMed1990

Therapeutic intervention in mentally retarded adult epileptics.

Clinical features of epilepsy, especially those connected with drug therapy, were evaluated for mentally retarded adult epileptics who were admitted to the neurological out-patient unit during 1977-83. These features were re-evaluated in 1985 and compared with findings from the first visit. During follow-up, the type and frequency of seizures were determined and if possible, medical therapy was either concluded or changed. The therapeutic intervention resulted in the use of fewer and less toxic drugs, for which the serum concentrations were more often within recommended ranges. These aspects may be due to the significant decrease in seizure frequency observed. In order to provide patients with the most efficacious therapy, the therapeutic needs of mentally retarded adult epileptics should be evaluated by a neurologist familiar with epilepsy.

Adolescent↗
PubMed1990

Compartmental analysis of short-lived platelet dynamics.

111In-labelled platelets were used for analysing platelet dynamics in 43 patients with idiopathic thrombocytopenic purpura (ITP). The detected time-activity curves, recorded with a gamma camera, were analysed by three methods: two- and three-compartment models, and an open model in which only the splenic curve was analysed. In the two-compartment model the mean rate constant from blood to spleen was 0.328 +/- 0.028 min-1 (mean +/- SEM) and from spleen to blood 0.061 +/- 0.007 min-1, whereas in the three-compartment model the corresponding values were 0.236 +/- 0.020 and 0.044 +/- 0.007 min-1, respectively. The mean rate constant from blood to liver was 0.466 +/- 0.149 min-1 and from liver to blood 0.341 +/- 0.106 min-1 as derived from the three-compartment model. The rate constant from spleen to blood, as determined from the three-compartment model, was significantly higher in patients with a strongly positive result for platelet-associated auto-antibodies (platelet suspension immunofluorescence test (PSIFT] than in patients with a negative PSIFT. The mean hepatic net rate in patients with a high level of antibodies is into the liver, while in patients with little or no antibodies the net rate is into the blood pool. The mean half-life for the fast component of the inverted splenic curve was 2.5 +/- 0.2 min and for the slow component 16 +/- 2 min. In patients with a strongly positive PSIFT the half-life for the slow component was significantly longer than in patients with a negative PSIFT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Serological evidence of viral or Mycoplasma pneumoniae infection in acute maxillary sinusitis.

Evidence for the involvement of viruses, Mycoplasma pneumoniae, and Chlamydia spp. was studied by the complement fixation test in paired sera from 310 young adults (297 men and 13 women) with acute maxillary sinusitis. The diagnosis of acute sinusitis was confirmed by radiography and sinus puncture. Elevated antibody titres were found in 102 patients (33%). A four fold or greater titre rise was detected in 21.5%, and a high stable titre suggestive of recent viral infection was present in a further 11.5%. Adenovirus, influenza A and B viruses, and Mycoplasma pneumoniae accounted for most of the elevated antibody titres. Elevated titres were found in 79 (32%) of the 245 patients with purulent maxillary sinusitis (pathogenic bacteria isolated in sinus secretion) and in 23 (35%) of the 65 patients with non-purulent sinusitis (no pathogenic bacteria isolated). About 90% of the fourfold or greater titre rises in bacteriologically negative cases were due to adeno- or influenza viruses. A fourfold rise in antibody titre was also found in 7 of 101 control patients (7%). The results of this study suggest that respiratory viruses and Mycoplasma pneumoniae may be potential etiological agents in acute maxillary sinusitis, either alone or in combination with the common bacterial pathogens of sinusitis.

Adolescent↗
PubMed1989

Allergy in patients with acute maxillary sinusitis.

The occurrence of allergy was studied in 224 patients with verified acute maxillary sinusitis by means of an allergy questionnaire, skin testing, and nasal smears. Allergy was found in 56 patients (25%). In addition, allergy was considered probable in 14 patients (6.5%). The corresponding percentages in the control group were 16.5 and 3, respectively. The difference is statistically significant P less than 0.05). However, the frequency of allergy is lower in the present series than in those previously reported on chronic sinusitis. There were no differences between allergic and non-allergic patients in the number of prior acute sinusitis episodes or of previously performed sinus irrigations. Bacteriological and radiological findings did not differ significantly between the groups.

Acute Disease↗
PubMed1989

Comparison of the nasal bacterial floras in two groups of healthy subjects and in patients with acute maxillary sinusitis.

The nasal bacterial flora was studied in 183 healthy men entering military service (entry group), 103 healthy recruits in service (service group), and 185 recruits with acute maxillary sinusitis. The 267 nasal and ipsilateral sinus aspirate findings in the same patients with acute maxillary sinusitis were compared pairwise. In the entry group presumed sinus pathogens were only rarely isolated from the nasal cavities: Haemophilus influenzae in 4%, Streptococcus pneumoniae in 1%, Branhamella catarrhalis in 3%, and Streptococcus pyogenes in 0%. The corresponding isolation frequencies in the service group were 19, 13, 3, and less than 1%, respectively, and those in the group with acute maxillary sinusitis were 61, 25, 7, and 6%, respectively. Suppression of the major components of the normal nasal flora, Corynebacterium sp., coagulase-negative staphylococci, Propionibacterium acnes, and Staphylococcus aureus, was seen in the group with acute maxillary sinusitis and also occasionally in the service group. When a sinus aspirate culture yielded a presumed sinus pathogen, the same pathogen was found in the nasal samples in 91% of the cases. The predictive value of a pathogen-positive nasal finding was highest (93.8%) for S. pyogenes, followed by 77.7% for H. influenzae and 68.7% for S. pneumoniae, and lowest (20%) for B. catarrhalis.

Adolescent↗