Biomedical subjects

M Bajc

Publications and source records attributed to M Bajc.

At least 19 recordsLinked to original sources

PubMed2001

Follow-up of acute pyelonephritis in children by Tc-99m DMSA scintigraphy: quantitative and qualitative assessment.

PURPOSE: The author's goal was to create a system to identify children at risk for development of progressive renal damage. METHODS: Thirty-four children were examined with Tc-99m DMSA scintigraphy in the acute stage of an initial episode of pyelonephritis, after 6 months, and again after 1 year. The scintigraphic findings were correlated with clinical and laboratory data. RESULTS: All children had parenchymal defects in the acute stage: 93% of the kidneys and 85% bilaterally. After 6 months, the defects had diminished or disappeared in 66% of the kidneys. New defects appeared in 22%. At 1 year, no further improvement was seen in the kidneys, with an improved or unchanged pattern at 6 months. New defects appeared in 34%. Mean kidney activity uptake expressed as the percentage of administered dose (KU/AD), was low in the acute stage, increased at 6 months, with no further significant increase at 1 year. Eighty-three percent of children with urine cultures growing > or = 104 bacteria/ml at follow-up had decreased KU/AD values, whereas all children with urine cultures growing < 104 bacteria/ml had increased KU/AD values. CONCLUSIONS: Quantitative assessment increases the sensitivity of Tc-99m DMSA scintigraphy. Follow-up with this method makes it possible to identify the children with decreasing renal tubular function who may be at risk for progressive renal damage. Moderate bacteruria of 104 bacteria/ml urine is associated with deterioration of renal tubular function.

Acute Disease↗

PubMed2001

Comprehensive ventilation/perfusion SPECT.

UNLABELLED: Lung scintigraphy is the primary tool for diagnostics of pulmonary embolism. A perfusion study is often complemented by a ventilation study. Intermediate probability scans are frequent. Our goal was to develop a fast method for tomographic ventilation and perfusion scintigraphy to improve the diagnostic value of lung scintigraphy. METHODS: SPECT was performed with a dual-head gamma camera. Acquisition parameters were determined using a thorax phantom. Ventilation tomography after inhalation of 30 MBq (99m)Tc-diethylenetriaminepentaacetate (DTPA) aerosol was, without patient movement, followed by perfusion tomography after an intravenous injection of 100 MBq (99m)Tc-labeled macroaggregated albumin (MAA). Total SPECT acquisition time was 20 min. (99m)Tc-DTPA clearance, calculated from initial and final SPECT projections, was used for correction of the ventilation projection set before iterative reconstruction of ventilation and perfusion. The ventilation background was subtracted from the perfusion tomograms. A normalized ventilation/perfusion quotient (V/P quotient) image set was calculated. The method was evaluated on a trial group of 15 patients. RESULTS: Ventilation and perfusion images had adequate quality and showed ventilation/perfusion (V/Q quotient) relationships more clearly than did planar images. Frontal and sagittal slices were superior to planar scintigraphy for characterization of embolized areas. The V/Q quotient was supportive, particularly in the patients with chronic obstructive pulmonary disease. CONCLUSION: Fast, high-quality, ventilation/perfusion SPECT with standard isotopes doses is feasible and may contribute to higher objectivity in evaluating lung embolism as well as other lung diseases. The costs for the procedure and patient care until diagnosis are low because of the comprehensive system for the study and, particularly, the short time for its completion.

Algorithms↗

PubMed2000

[Examination of gastric emptying with gamma camera. Clinically useful, uniform method now established].

Although more than 30 years have passed since the introduction of scintigraphic testing of gastric emptying there has been no well-defined standard. Eight Swedish hospitals have established a nationally standardized method for scintigraphic testing of gastric emptying of solids. 160 healthy subjects participated. The meal consisted of a 99mTc-labeled omelet (1300 kJ) and 150 ml unlabeled soft drink (290 kJ). There were no differences in calculated variables between the centers. Premenopausal women showed slower emptying than postmenopausals and men of any age, making separate reference values for younger women necessary.

Adult↗

PubMed2000

Partitioning of dead space--a method and reference values in the awake human.

Although dead space is often increased in disease, it is not frequently measured in the clinic. This may reflect that an adequate method as well as reference values are missing. Healthy males and females, n=38, age 20-61 yrs, were connected to a pneumotachograph and a fast CO2 analyser after radial artery catheterization. The physiological dead space was partitioned into airway and alveolar dead space using a delineation principle denoted the pre-interface expirate. Physiological dead space was 201+/-41 mL in males and 150+/-34 mL in females. Dead space values were depending upon parameters reflecting lung size (predicted total lung capacity), breathing pattern and age. After multiple correlation the variation decreased and differences between males and females disappeared. The residual SD was then for physiological dead space 18.9 mL. The clinical use of the new method for determination of dead space can be based upon reference values, with a more narrow range than previous data.

Adult↗

PubMed1999

Radioisotope evaluation of the esophageal remnant and the gastric conduit after gastric pull-up esophagectomy.

BACKGROUND: The act of swallowing after gastric pull-up esophagectomy has not been thoroughly investigated. The aim of this study was to evaluate deglutition in the esophageal remnant and in the gastric conduit in patients who have undergone this operation. METHODS: The residual radionuclide activity was measured 15 seconds after a swallow in the esophageal remnant and at intervals up to a maximum of 120 minutes after a swallow in the gastric conduit. The scintigraphic rate of transit of a bolus in both areas was compared in patients who had anastomosis in the neck (n = 15) versus patients who had anastomosis in the chest (n = 19). Comparisons were also made between patients with and without symptoms of dysphagia. The scintigraphic measurements were also correlated with anastomotic diameters, measured with use of a volumetric balloon insufflation method, at 3, 6, and 12 months after operation. RESULTS: There were no significant differences in esophageal residual radionuclide activity at 15 seconds after a swallow in the groups with anastomosis in the neck versus anastomosis in the chest, with 30% residual activity up to 12 months after operation in both groups (P = .24). In the patients as a whole the 50% gastric conduit emptying time of 44 to 61 minutes did not change during the first postoperative year (P = .12). There was no association between anastomotic diameter and residual activity in the remaining esophagus (P < .126). Moderate and severe dysphagia was reported in only a few patients, and there was no correlation between dysphagic symptoms and retention in the residual esophagus or slower emptying in the gastric conduit. CONCLUSIONS: The amount of peristaltic activity in the remaining esophagus after esophagectomy with gastric replacement is unaffected by the level of the anastomosis. The gastric conduit empties slowly in all patients, and there is no correlation between the rate of emptying and either anastomotic diameter or symptoms of dysphagia.

Analysis of Variance↗

PubMed1997

Kidney size estimation in piglets using dimercaptosuccinic acid (DMSA) scintigraphy.

The objective of this study was to validate kidney size measurements obtained by DMSA scintigraphy in kidneys of sizes relevant in paediatric practice. Kidney length, width and volume were measured by DMSA scintigraphy in 10 piglets in vivo and compared with measurements on excised kidneys using callipers, planar scintigraphy and submersion in water. In addition, a kidney phantom was constructed and placed in a torso phantom. The length, width and volume of the kidney phantom were compared with planar and tomographic scintigraphic measurements. The mean overestimation of kidney length by scintigraphy was 1.7% (+/- 1.2%) on excised kidneys and 3.9% (+/- 2.4%) in vivo. The corresponding figures for width measurements were 7.0% (+/- 3.9%) and 7.8% (+/- 4.4%). Tomography volume estimation overestimated the submersion volume by 23% (+/- 12%). Scintigraphic measurements on the phantom over-estimated length by 5%, width by 8% and volume by 11%. Scintigraphic renal length measurements are reliable and differ from the anatomical length by < 4% compared with excised kidneys and < 8% in vivo. Scintigraphic width measurements and volume estimations, especially on small kidneys, are less reliable.

Animals↗

PubMed1997

Kidney swelling. Findings on DMSA scintigraphy.

OBJECTIVE: To develop criteria identifying swollen kidneys on dimercaptosuccinic acid (DMSA) renal scintigraphy in acute pyelonephritis with regard to the DMSA distribution pattern, kidney functional size, and radioactive uptake. SUBJECTS AND METHODS: Thirty-eight children aged 15 days to 7 years with known pyelonephritis were examined with DMSA renal scintigraphy. All children were observed 2 or 3 times. In total, 94 scintigrams were evaluated. Qualitative and quantitative criteria for swelling were defined. RESULTS: Thirty-one observed kidneys satisfied the criteria of swelling. Quantitatively, kidney length and width/length were greater in swollen kidneys. Kidney uptake in percent of injected dose and kidney uptake/background were lower in swollen kidneys. Qualitatively, focal radioactive uptake defects known from a previous examination were sometimes obscured by swelling, and reappeared at follow-up. In 5 children with signs of swelling on repeat imaging, scintigraphy reinfection at the time of swelling was verified. CONCLUSIONS: Swollen kidneys may be the only sign of acute pyelonephritis on DMSA scintigraphy and swelling may obscure focal radioactive uptake defects. Measurement of kidney size and radioactive uptake can help identify swollen kidneys at DMSA scintigraphy and disclose acute pyelonephritis in the absence of overt clinical symptoms.

Acute Disease↗

PubMed1996

Dynamic indium-111-pentetreotide scintigraphy in breast cancer.

UNLABELLED: The efficacy of imaging breast cancer with 111In-pentetreotide (somatostatin receptor scintigraphy) was evaluate before surgery. METHODS: Seventy-one whole-body scintigrams in 24 patients with known breast cancer and 24 whole-body scintigrams in 8 controls were obtained at 0.5, 5 and 24 hr after intravenous injection of 110 MBq 111In-pentetreotide. Anterior and posterior projection images were acquired simultaneously. SPECT of the thorax was performed at 5 or 24 hr after injection in all breast cancer patients. The specimens were imaged immediately after surgery and the distribution of pentetreotide was assessed qualitatively and quantitatively. RESULTS: Somatostatin receptor-positive tumors were found in 18/24 patients with breast cancer. Pentetreotide uptake was significantly greater in breast cancer patients compared to control patients. In all patients with positive images, the early scintigram (0.5 hr) showed abnormal uptake. It was possible to delineate three different dynamic patterns. Increased uptake was visually most distinct at each time (9 patients). Moreover, bilaterally increased pentetreotide uptake was observed in 10/18 true-positive patients (in 8 at each time and in 2 patients only at 5 hr), but only one patient had a known bilateral tumor. CONCLUSION: We found higher incidence of somatostatin receptors in patients with breast cancer than in the control group. Moreover, bilaterally increased pentetreotide uptake in clinically unilateral disease was an unexpected finding.

Breast Neoplasms↗

PubMed1995

Tc-99m DMSA renal scintigraphy during kidney maturation.

A total of 282 renal scintigrams with Tc-99m DMSA in 238 children ranging in age from 10 days to 13 years performed during a 3-year period were reviewed. The authors present 94 kidneys in 85 children in whom no sign of pathology was demonstrated clinically, either by ultrasound or intravenous urography, or by micturating urethrocystography. By exploring homogeneity or heterogeneity of tracer distribution, kidney length, and background level, the authors were able to identify a "normal" pattern of tracer distribution according to age. They found that the average kidney length was 56 mm at birth, growing 1 mm per month during the first year of life, and 4 mm per year thereafter, until puberty. Average background activity was 14% of the average kidney activity at birth which decreased to approximately 6% during the first year of life, with no further decrease thereafter.

Child↗

PubMed1995

Renal function up to 16 years after conduit (refluxing or anti-reflux anastomosis) or continent urinary diversion. 2. Renal scarring and location of bacteriuria.

OBJECTIVE: To evaluate the importance of refluxing versus anti-reflux ureteric implantation for the development of renal scarring in patients with a conduit or continent urinary diversion and for the incidence of bacteriuria in the upper urinary tract of patients with a conduit. PATIENTS AND METHODS: Renal scintigraphy using 99mTc-dimercaptosuccinic acid was performed on 32 of 37 evaluable patients from a prospective, randomized study at a mean of 150 months (range 102-198) after urinary diversion. In five patients with a conduit diversion and unilateral renal scarring, urine was samples for culture from the proximal end of the conduit and from both renal pelvices by direct percutaneous aspiration. RESULTS: Of 35 renal units (18 patients), studied after conduit diversion, scarring was found in 11 (two grade I, six grade II and three grade III) of 17 with refluxing anastomosis and in six (one grade I, four grade II and one grade III) of 18 with anti-reflux anastomosis (P = 0.06). Of 25 renal units (14 patients) after continent diversion, 16 showed scarring (seven grade I and nine grade II). Bacteriuria was found in four of five upper urinary tracts with a refluxing anastomosis, but in only one of five with an anti-reflux anastomosis. In these five patients scarring was present in all kidneys with refluxing anastomosis. CONCLUSION: Anti-reflux ureteric anastomosis seems to be important for preventing scarring and bacteriuria in the upper urinary tract of patients with a conduit urinary diversion. Despite the anti-reflux technique of ureteric implantation, most patients with a continent reservoir had renal scarring, though it was generally less severe than in patients with a conduit urinary diversion.

Bacteriuria↗

PubMed1995

Dynamic Octreotide scintigraphy in neuroendocrine tumours.

The purpose of the present study was to investigate the optimal time for scintigraphy after injection of the radio-labelled somatostatin analogue, Octreotide. A secondary purpose was to evaluate the value of SPECT. One SPECT study and up to 4 whole body scans were performed in 22 patients with neuroendocrine tumours 0.5, 5, 24 and 48 hours after an injection of 110 MBq In-DTPA Octreotide. A total of 98 scintigrams were studied. A pathological uptake was found in 19 of the 22 patients. In 3 cases, early scintigrams (0.5 and 5 hours after injection) were of the most value whereas late scintigrams (24 and 48 hours) were the best in 4 cases. SPECT was found to be of value in 13 of 21 cases. For correct interpretation of Octreotide scintigraphy it is necessary to obtain both early and late scintigrams as well as a SPECT study.

Adult↗

PubMed1994

The significance of vesicoureteric reflux on kidney development assessed by dimercaptosuccinate renal scintigraphy.

OBJECTIVE: To study the influence of vesicoureteric reflux on kidney parenchyma and renal length, and identify typical distribution patterns by dimercaptosuccinate (DMSA) renal scintigraphy. PATIENTS AND METHODS: DMSA renal scintigraphies in 101 children (152 renal units) with vesicoureteric reflux grade 1-5 were reviewed. RESULTS: Three main types of pathological DMSA patterns were found: (i) dysplasia; (ii) medial defect; and (iii) pole defects. In children with no history of pyelonephritis a normal distribution pattern was found in 31%, dysplasia in 23%, medial defect in 25%, pole defects in 17% and no typical pattern in 4%. In those with a history of pyelonephritis a normal distribution pattern was found in 28%, dysplasia in 24%, medial defect in 21%, pole defects in 24% and no typical pattern in 3%. A normal pattern was significantly more frequent in kidneys with reflux grade 1-2. Dysplasia was significantly more frequent in kidneys with reflux grade 4-5. In children with no history of pyelonephritis 42% of the renal units had reduced length, 8% with no other sign of pathology. The frequency of reduced kidney length at reflux grade 1-2 did not differ significantly from that at higher grades of reflux. In children with a history of pyelonephritis 52% of the renal units had reduced length, 13% with no other sign of pathology. The frequency of reduced kidney length with a normal DMSA pattern did not differ significantly from that with a pathological pattern. CONCLUSION: The pathological DMSA distribution with vesicoureteric reflux generally conforms to one of three main patterns. Reduced kidney length is frequent even at lower grades of vesicoureteric reflux even in patients with no history of pyelonephritis, and can be the only sign of pathology.

Adolescent↗

PubMed1994

Distribution and dosimetry of 111In DTPA-D-Phe-octreotide in man assessed by whole body scintigraphy.

The distribution and dosimetry of the somatostatin analog 111In-DTPA-octreotide was evaluated in 6 patients. Whole body scintigraphy in anterior and posterior projections was performed 0.5, 5, 24 and 48 hours after injection. Region-of-interest analysis for different organs and the whole body was used to determine 111In octreotide half-life-corrected uptake in absolute and relative terms. A rapid initial uptake was seen in the kidneys (2-7%), the spleen (2-6%) and in the liver (4-8%). A lower uptake was seen in the pituitary gland (maximum 0.3%), the thyroid (maximum 0.07%), in the female breast (maximum 1.2%), in the urinary bladder and in the intestinal tract. The elimination pattern varied between different organs. The effective dose equivalent was evaluated to be in the range 0.08 to 0.13 mSv/MBq (average 0.10 mSv/MBq). The behavior of 111In-DTPA-octreotide suggests follow-up scintigraphy in a period extending up to at least 24 hours after injection.

Absorption↗

PubMed1993

Typical technetium dimercaptosuccinic acid distribution patterns in acute pyelonephritis.

Technetium dimercaptosuccinic acid renal scintiscans in 37 children with clinical diagnosis of acute pyelonephritis were reviewed. In 18 children, follow-up scintigraphy was obtained after an interval ranging from 5 to 8 months. Uptake abnormalities were found in 89% of the children (74% of the kidneys). We were able to identify four typical pathological uptake patterns: (i) pole defect(s), usually wedge shaped (60%); (ii) lateral wedge shaped defect (4%); (ii) scattered multiple defects (21%); and (iv) swollen kidney without areas of diminished uptake (15%). Remaining pathology at follow-up was found in 52% of the kidneys. Vesicoureteric reflux was present in 33% of the children with scintigraphic signs of pyelonephritis. Frequencies of parenchymal changes in the acute phase and at follow-up were not significantly correlated to the presence of reflux.

Acute Disease↗

PubMed1991

Regional brain perfusion changes in patients with primary generalized epilepsy assessed by Tc99m HM-PAO and SPECT.

Cerebral distribution of Tc99m-hexamethylprolenaminoxim (HMPAO) was investigated using single photon emission computerized tomography (SPECT) in 34 patients with primary generalized epilepsy (PGE) during the interictal state. These findings were compared with those in a control group of 9 healthy volunteers. In control subjects uniform selective uptake of HMPAO in cortex, basal ganglia and thalamus was found. In 30 patients (88%) decreased regional perfusion was found as follows: in the cortical region in 6 patients (18%), in the region of the basal ganglia or thalamus in 7 (20%), and in both regions in 17 patients (50%). Four patients had normal SPECT findings. The obtained results permit a hypothesis that the PGE should not be strictly differentiated from the focal epilepsy. A possible explanation of the pathophysiology of PGE has also been discussed.

Adolescent↗

PubMed1991

Volumes of chronic traumatic frontal brain lesions measured by MR imaging and CBF tomography.

The volumes (ml) of chronic traumatic frontal brain lesions were compared measured "morphologically" with MR imaging (T1 and T2 weighted images) and "functionally" with a tomographic rCBF technique (SPECT with 133Xe i.v.). The T1 volumes varied between 11 and 220 ml. The correlation between T1 and T2 volumes was 0.95, the T2 volumes being 33% larger than T1 volumes (p less than 0.001). The functional SPECT volumes were considerably larger (range 16-324 ml) than the MR volumes. The mean volume difference was 81% between T1 and SPECT images (p less than 0.001), and 35% between T2 and SPECT images (p less than 0.001). Correlations between the MR and SPECT volumes were also higher for T2 than T1 volumes. The volume difference is most likely explained by a functional decrease in regions around the lesion in which no morphologic change visible on MR images had taken place. MR and SPECT volume measurements were positively related to persistent lack of energy and personality changes, but only moderately related to duration of impaired consciousness and neuropsychologic outcome.

Adult↗

PubMed1991

Brain shunts in patients with stroke: possible cerebral autoregulation of changed haemodynamics.

The cerebral perfusion was evaluated in 8 patients with stroke, caused by stenosis or occlusion of the carotid artery, and in 4 neurologically healthy subjects, using Tc99m labeled microspheres (LMS). By measuring activity in the brain and lungs after intracarotid injection of LMS, the existence of brain shunts in patients with stroke was demonstrated. It seems that brain ischaemia triggers the opening of shunts which appear to be one of the important autoregulatory and protective mechanisms to cerebral haemodynamic changes after brain infarction.

Adult↗

PubMed1990

Haemodynamic changes in patients with subarachnoid haemorrhage assessed by Tc99m labeled albumin microspheres.

The aim of the present study was the investigation of haemodynamic changes in the brain in patients after subarachnoid haemorrhage (SAH) using Tc 99 m labelled albumin microspheres (LMS). Twenty-nine patients after SAH (13 in the acute and 16 in the chronic stage of the disease) and four neurologically healthy subjects were examined. LMS were injected in the carotid during angiography and brain and lung scintigrams were taken using gamma camera. In the control subjects a diffuse and uniform distribution of the activity in the brain was found. In the patients with acute SAH "patchy", nonhomogenous distribution of the activity was found, ranging up to the regional absence of perfusion. This pattern was observed in the chronic stage as well, but less obvious than in the acute. In all the patients the evident trapping of LMS in the lungs was demonstrated confirming brain shunts, absent in the control group. By measuring the activity in the brain and lungs after intracarotid injection of LMS, haemodynamic changes in the patients after SAH were proved and the existence of brain shunts was demonstrated. It seems that shunts are functional anastomoses and important protective mechanism, opening when cerebral haemodynamics is altered.

Adult↗