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At least 1,621 records · Page 90Linked to original sources
PubMed1994

Technetium 99m-MDP scintigraphy of patients undergoing implant prosthetic procedures: a follow-up study.

The clinical evaluation of peri-implant tissue is mainly based on x-rays. In recent years, radioisotope scintigraphy using Tc-99m-MDP (technetium-99m-methylene diphosphonate) proved to be a useful and reliable clinical method for measuring increased metabolic activity at specific sites of the skeletal tissue. Twenty-six (26) patients (26 to 75 years) who were diagnosed for implant prosthetic treatment modality were randomly chosen to participate in this study. Each patient was injected with 20 mCi of Tc-99m-MDP was scanned 2 hours later by gamma-camera for isotope uptake levels in the jaws. Each patient was scanned 1 to 4 times, starting 2 weeks after implant surgery and up to the 40th week postsurgery. Blade and screw type implants using the non-submerged, one-stage technique were placed. Therefore, the prosthetic reconstruction was initiated 2 weeks after implant surgery. In order to compare the different scans we formulated a relative "bone scan index" (BSI). The results of 62 scans were plotted as BSI against time after implant surgery. A mathematical regression analysis of the BSI was also performed. At the initial stage of 2 to 3 weeks after surgery the BSI is high and then gradually declines. While BSI of the implants in the mandible reaches baseline levels after 12 weeks, the BSI in the maxilla reaches baseline only after 20 weeks. On the other hand, there was no difference in BSI with regard to blade or screw type implant. Here we were able to demonstrate that the process is independent of implant modality and depends on the specific metabolic properties of the jaw.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Diagnosis of infection in ununited fractures. Combined imaging with indium-111-labeled leukocytes and technetium-99m methylene diphosphonate.

The results of combined scintigraphy in which indium-111-labeled leukocytes and technetium-99m methylene diphosphonate were used were compared with the results of cultures of open bone at 102 sites of delayed union or non-union, to determine the effectiveness of this combination as a preoperative indicator of osteomyelitis. There were twenty-five true-positive, fifty-nine true-negative, eleven false-positive, four false-negative, and three indeterminate interpretations, yielding, for the diagnosis of osteomyelitis, a sensitivity of 86 per cent, a specificity of 84 per cent, an accuracy of 82 per cent, a positive predictive value of 69 per cent, and a negative predictive value of 94 per cent. There were few false-negative scans; false-positive results were most likely at a metaphyseal site adjacent to a joint in which there was post-traumatic arthropathy, at the site of a failed arthrodesis, and at the site of an unstable delayed union or non-union.

Adolescent↗
PubMed1994

Undiagnosed fractures in severely injured children and young adults. Identification with technetium imaging.

A whole-body bone scan was performed to search for undetected fractures in forty-eight patients who had multiple injuries or a head injury, or both, and who were less than twenty-two years old. The study took place from January 1991 to July 1992. Radiographs had been made of all areas of suspected skeletal trauma at the time of admission. Follow-up plain radiographs were made of all areas where unexpected abnormal tracer activity was noted. Forty-two of these areas were noted in eighteen skeletally immature patients and fifty-two, in twelve skeletally mature patients. Nineteen previously unrecognized fractures were identified in the subsequent radiographic analysis. Four skeletally immature and two skeletally mature patients had an alteration in treatment on the basis of the identification of a previously undiagnosed injury. Each of these six patients had a cast applied. A fracture was identified three weeks or more after the injury in two skeletally mature patients. These fractures would have been treated (one with a cast and the other with open reduction and internal fixation) if they had been diagnosed earlier. We believe that this analysis demonstrates the usefulness of technetium radionucleotide bone-imaging, as an adjuvant to the orthopaedic examination, in the identification of undiagnosed musculoskeletal injuries in a patient who is less that twenty-two years old and who has sustained a head injury or multiple injuries, or both.

Adolescent↗
PubMed2006

Technetium-99m sestamibi single photon emission computed tomography findings correlated with P-glycoprotein expression in pituitary adenoma.

The aim of this study is to evaluate whether the technetium-99m sestamibi ((99m)Tc-MIBI) single photon emission computed tomography (SPECT) characteristics of pituitary adenomas might be correlated with cavernous sinus invasion, proliferative potential or the multidrug-resistance (MDR-1) gene product P-glycoprotein (Pgp) expression in pituitary adenomas. Fifteen patients with pituitary adenomas, including 10 nonfunctioning adenomas, two prolactinomas, two GH producing adenomas, and one ACTH producing adenomas was investigated for this study. SPECT images with (99m)Tc-MIBI were acquired 15 minutes (early) and 3 hours (delayed) after injection. The tumor-to-normal brain ratio was calculated both early (ER) and delayed (DR) images. Retention index (RI) was calculated using the following formula: (DR-ER)/ERx100%. The pituitary adenomas specimens were examined by immunohistochemistry using anti-Pgp and MIB-1 monoclonal antibodies.(99m)Tc-MIBI SPECT findings were not related to MIB-1 labeling index or cavernous sinus invasion. (99m)Tc-MIBI SPECT RI (-38.55+/-20.77) of the Pgp-positive group was significantly lower than that (-15.78+/-19.40) of Pgp-negative group (p=0.0494). No significant difference was observed in the ER and DR of (99m)Tc-MIBI SPECT between Pgp-positive and negative groups. Our study suggests that although (99m)Tc-MIBI SPECT is not useful to evaluate the proliferative potential or cavernous sinus invasion of pituitary adenomas. (99m)Tc-MIBI SPECT could predict anti-cancer drug resistance related to the expression of Pgp in pituitary adenomas.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Parathyroid carcinoma with metastatic calcification identified by technetium-99m methylene diphosphonate scintigraphy.

We describe herein a case of parathyroid carcinoma accompanied with metastatic calcification identified by technetium-99m methylene diphosphonate (Tc-99m MDP) scintigraphy in the lungs, kidneys and stomach. Parathyroid carcinoma remains a rare disorder despite the increased prevalence of primary hyperparathyroidism. Metastatic calcification is noted infrequently even in primary hyperparathyroidism and it may cause respiratory failure. Tc-99m MDP scintigraphy three months after surgery showed a complete disappearance of Tc-99m uptake in the stomach and an obvious reduction in the kidneys but no significant change in the lungs, indicating metastatic calcification can be reversibly reabsorbed. This case indicates that the adequate excision of parathyroid carcinoma as well as the early detection of metastatic calcification by Tc-99m MDP are obligatory.

Calcinosis↗
PubMed2000

The effect of drugs on the labeling of blood elements with technetium-99m.

The influence of drugs on the labeling of red blood cells and plasma proteins with 99mTc has been reported. Any drug, which alters the labeling of the tracer, could be expected to modify the disposition of the radiopharmaceuticals. Red blood cells (RBC) labeled with technetium-99m (99mTc) are used for several evaluations in nuclear medicine. We have evaluated the effect of Thuya occidentalis, Peumus boldus and Nicotiana tabacum (tobacco) extracts on the labeling of RBC and plasma and cellular proteins with 99mTc. Blood was incubated with the drugs. Stannous chloride (SnCl2) solutions and 99mTc were added. Plasma (P) and blood cells (BC) were separated. The percentage of radioactivity (%ATI) bound to P and BC was determined. The %ATI on the plasma and cellular proteins was also evaluated by precipitation of P and BC samples with trichloroacetic acid (TCA) and isolation of soluble (SF) and insoluble (IF) fractions. The analysis of the results shows that there is a decrease in %ATI (from 97.64 to 75.89 percent) in BC with Thuya occidentalis extract. The labeling of RBC and plasma proteins can be decreased in presence of tobacco. This can be due either a direct or indirect effect (reactive oxygen species) of tobacco. The analysis of radioactivity in samples of P and BC isolated from samples of whole blood treated with Peumus boldus showed a rapid uptake of the radioactivity by blood cells in the presence of the Peumus boldus, whereas there was a slight decrease in the amount of 99mTc radioactivity in the TCA-insoluble fraction of plasma. This study shows that extracts of some medicinal plants can affect the radiolabeling of red blood cells with 99mTc using an in vitro technique.

Animals↗
PubMed1993

Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo.

Tissue-type plasminogen activator (t-PA) effectively lyses active thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m (99mTc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. 99mTc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. 99mTc-labeled human serum albumin was not retained at clot sites. Systemically administered 99mTc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear.

Animals↗
PubMed1994

Assessment of the brain areas perfused by superselective intra-arterial chemotherapy using single photon emission computed tomography with technetium-99m-hexamethyl-propyleneamine oxime--technical note.

The brain areas perfused by superselective intra-arterial (i.a.) chemotherapy were assessed using single photon emission computed tomography (SPECT) with technetium-99m-hexamethyl-propyleneamine oxime (99mTc-HMPAO). A superselective catheter was introduced into the anterior, middle, or posterior cerebral artery of patients with malignant glioma for i.a. chemotherapy. 99mTc-HMPAO was subsequently injected via the same catheter used for chemotherapy, and a higher dose of 99mTc-HMPAO was injected intravenously to obtain adequate background brain images. Comparison of the SPECT images with magnetic resonance images could confirm complete perfusion of the tumor tissue. In two patients with malignant glioma, regions of interest were selected in the peritumoral brain area and a reference brain area, and the radioactivity was measured. The concentration of 99mTc-HMPAO was about 50 times higher in tissue perfused by superselective injection into anterior or middle cerebral artery compared to intravenous injection. 99mTc-HMPAO SPECT is readily available in many institutions and the information provided is useful for planning more effective and safe i.a. chemotherapy.

Adolescent↗
PubMed2002

Effect of expression of P-glycoprotein on technetium-99m methoxyisobutylisonitrile single photon emission computed tomography of brain tumors.

The expression of P-glycoprotein was investigated immunohistochemically in 26 brain tumor tissues and compared with the findings of technetium-99m methoxyisobutylisonitrile single photon emission computed tomography (99mTc-MIBI SPECT) to clarify the effect of P-glycoprotein on the diagnostic accuracy. P-glycoprotein labeling index of both tumor cells and vascular endothelial cells showed no clear relationship with the findings of 99mTc-MIBI SPECT imaging. Expression of P-glycoprotein has no effect on the diagnostic accuracy of 99mTc-MIBI SPECT.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Technetium-99m sestamibi single photon emission computed tomography findings correlated with P-glycoprotein expression, encoded by the multidrug resistance gene-1 messenger ribonucleic acid, in intracranial meningiomas.

The present study evaluated whether technetium-99m sestamibi (99mTc-MIBI) single photon emission computed tomography (SPECT) characteristics of intracranial meningioma are correlated with the histological malignancy, proliferative potential, and P-glycoprotein (Pgp) expression, encoded by the multidrug resistance gene-1 (MDR-1) messenger ribonucleic acid (mRNA). Twenty-one patients with intracranial meningiomas, including 17 benign and four nonbenign meningiomas, underwent 99mTc-MIBI SPECT imaging at 15 minutes (early) and 3 hours (delayed) after injection. The tumor-to-normal pituitary gland ratio was calculated on both early (ER) and delayed (DR) images. Retention index (RI) was calculated using the following formula: (DR - ER)/ER x 100%. Meningioma specimens were examined by immunohistochemistry using anti-Pgp and MIB-1 monoclonal antibody. MDR-1 mRNA expression was also investigated using reverse transcription-polymerase chain reaction assay. 99mTc-MIBI was highly accumulated and retained in the tumors. 99mTc-MIBI SPECT findings were not related to MIB-1 labeling index. 99mTc-MIBI SPECT RI of the Pgp-positive group (-9.12 +/- 22.27%) was significantly lower than that of the Pgp-negative group (28.79 +/- 22.80%) (p = 0.0016). No significant difference was seen in ER and DR between the positive and negative groups. These results show that 99mTc-MIBI may not be useful for determining proliferative potential and histological malignancy, but could predict anticancer drug resistance related to the expression of MDR-1 mRNA and its gene product Pgp in patients with intracranial meningiomas.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Effect of sample number and time on determination of plasma clearance of technetium Tc 99m pentetate and orthoiodohippurate sodium I 131 in dogs and cats.

OBJECTIVE: To determine the effect of number of blood samples and sampling times on plasma clearance of technetium Tc 99m pentetate (Tc99mP) and orthoiodohippurate sodium I 131(OIH). ANIMALS: 20 dogs and 14 cats. PROCEDURE: Plasma clearances of OIH and Tc99mP were calculated by use of a 2-compartment model, on the basis of a 12-point curve as a reference method. Plasma clearance was calculated by use of all possible combinations of 4 to 11 samples. Time schedule yielding the smallest difference from the reference method was considered to be optimal. Regression analysis was performed between the 12-point model and models using a reduced number of samples. RESULTS: SD of the difference between the 12-point clearance and the models with reduced numbers of samples increased when the number of samples decreased. The SD of the difference between 12-point clearance and 4-point clearance was 4.17 ml/min for OIH and 0.94 ml/min for Tc99mP in dogs and 0.45 ml/min for OIH and 0.11 ml/min for Tc99mP in cats. Optimal schedules were distributed logarithmically and included an early sample at 5 or 10 minutes, a late sample at 2.5, 3, 4, or 5 hours for OIH, and a late sample at 4 or 5 hours for Tc99mP. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma clearances of OIH and Tc99mP can be accurately calculated in dogs and cats by use of a single-injection 2-compartment pharmacologic model with a reduced number of blood samples, resulting in an acceptable margin of error.

Animals↗
PubMed2003

Determination of extrarenal plasma clearance and hepatic uptake of technetium-99m-mercaptoacetyltriglycine in cats.

OBJECTIVE: To determine maximum extrarenal plasma clearance of technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) and maximum extrarenal hepatic uptake of 99mTc-MAG3 in cats. ANIMALS: 6 clinically normal adult cats. PROCEDURES: Simultaneously, baseline plasma clearance and camera-based uptake of 99mTc-MAG3 were determined in anesthetized cats. Double exponential curves were fitted to plasma clearance data. Injected dose was divided by area under the curve and body weight to determine 99mTc-MAG3 clearance. Regions of interest were drawn around kidneys and liver, and percentage dose uptake was determined 1 to 3 minutes after injection. After bilateral nephrectomy, simultaneous extrarenal plasma clearance and camera-based hepatic uptake of 99mTc-MAG3 were evaluated in each cat. RESULTS: Mean +/- SD baseline plasma clearance and extrarenal clearance were 5.29 +/- 0.77 and 0.84 +/- 0.47 mL/min/kg, respectively. Mean extrarenal clearance (as a percentage of baseline plasma clearance) was 16.06 +/- 7.64%. For right, left, and both kidneys, mean percentage dose uptake was 9.42 +/- 2.58, 9.37 +/- 0.86, and 18.79 +/- 2.47%, respectively. Mean hepatic percentage dose uptake before and after nephrectomy was 12.95 +/- 0.93 and 21.47 +/- 2.00%, respectively. Mean percentage change of hepatic uptake after nephrectomy was 166.89 +/- 23.19%. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, extrarenal clearance of 99mTc-MAG3 is higher than that of other species; therefore, 99mTc-MAG3 is not useful for estimation of renal function in felids. Evaluation of renal function in cats may be more accurate via camera-based versus plasma clearance-based methods because camera-based studies can discriminate specific organs.

Animals↗
PubMed2005

Measurement of glomerular filtration rate via urinary clearance of inulin and plasma clearance of technetium Tc 99m pentetate and exogenous creatinine in dogs.

OBJECTIVE: To compare glomerular filtration rate (GFR) measured via urinary clearance of inulin (UCI) with plasma clearance of technetium Tc 99m pentetate (99mTc-pentetate) and creatinine in dogs. ANIMALS: 6 healthy Beagles and 18 Beagles with reduced renal function. PROCEDURE: 13 blood samples were obtained between 5 and 600 minutes after i.v. bolus injections of (99m)Tc-pentetate and creatinine. Plasma clearance of (99m)Tc-pentetate was computed on the basis of 1, 2, or 13 samples, and plasma clearance of creatinine was computed on the basis of 2, 5, or 13 samples. During plasma clearance procedures, constant i.v. infusion of carboxyl carbon 14 inulin was begun and UCI was determined in urine collected from 90 to 120, 120 to 180, and 180 to 240 minutes. Clearance procedures were repeated in 12 dogs to evaluate reproducibility of results. RESULTS: Significant association between UCI and plasma clearance was determined via all methods. However, plasma clearances were moderately to markedly different from UCI, depending on test substance, GFR, and sample numbers used for plasma clearance computations. Comparisons were particularly discordant when some methods of limiting samples were used to define plasma clearance. CONCLUSIONS AND CLINICAL RELEVANCE: Values derived from plasma clearance methods for (99m)Tc-pentetate and creatinine were not interchangeable with UCI results, which raises questions about their reliability as clinical research tools for measurement of GFR. Plasma clearance methods that are relative indices of renal function should not be interpreted as accurate measures of GFR without validation.

Analysis of Variance↗
PubMed1996

Comparison of chemotaxis and superoxide generation of indium-111-oxine- and technetium-99m-HMPAO-labelled granulocytes.

The diagnostic value of imaging infection with labelled granulocytes depends on the functional integrity of the reinfused cells. The aim of this study was to compare the functional integrity of granulocytes labelled with indium-111-oxine and technetium-99m-hexamethylpropyleneamineoxime (HMPAO), respectively, in comparison to unlabelled control granulocytes. Granulocytes were purified from healthy subjects and labelled with either 111In-oxine or 99mTc-HMPAO. Chemotaxis and superoxide production induced by formyl-peptide and phorbol-myristate-acetate were measured. Granulocytes labelled with 111In-oxine had significantly (p < 0.001) decreased chemotaxis. Superoxide production of granulocytes stimulated with phorbol-myristate-acetate showed no significant difference between control cells and those labelled using either technique. In contrast, formyl-peptide-stimulated superoxide production was increased in granulocytes labelled with 111In-oxine (p < 0.01) and in cells labelled with 99mTc-HMPAO (p < 0.03), indicating a priming compared to unlabelled cells. In conclusion, 99mTc-HMPAO-labelled granulocytes show biological properties superior to 111In-oxine-labelled cells, and should therefore be favoured for use in leucocyte labelling and infectious disease imaging.

Chemotaxis, Leukocyte↗
PubMed1992

Do technetium-99m hexamethylpropylene amine oxime-labeled leukocytes truly reflect the mucosal inflammation in patients with ulcerative colitis?

Twenty-five patients with ulcerative colitis and nine controls with macroscopically non-inflamed colon were investigated with technetium-99m hexamethylpropylene amine oxime-labeled leukocyte scintigraphy and colonoscopy with biopsies. The interval between leukocyte scintigraphy and colonoscopy was < or = 14 days in all patients with ulcerative colitis and < or = 30 days in eight of nine controls. Scintigrams were obtained at approximately 45 min and 4 h after injection of labeled leukocytes. One nuclear physician, one internist, and one pathologist graded blindly and independently of each other the degree of active inflammation in seven different colonic segments for each patient, using 4-grade scales for scans and macroscopically and histologically viewed inflammation, respectively. A positive correlation between endoscopic and histologic grading of all colonic segments and scan gradings for all subjects and for ulcerative colitis patients separately was found (all, p < 0.001). By means of kappa statistics, the inter-observer agreement between scintigraphic grading at 45 min and endoscopy was, for all subjects, 0.32 (95% confidence interval (CI), 0.20-0.44; p < 0.001) and, for patients with ulcerative colitis, 0.19 (CI, 0.07-0.31; p < 0.001). When 17 patients who had complete colonoscopies were divided into those with total, extensive, or distal colitis, leukocyte scintigraphy underestimated the extension of active inflammation. A simple scintigraphic scoring system reflects the colonic inflammation viewed endoscopically and histologically in patients with ulcerative colitis but underestimates the presence of active inflammation in individual colonic segments.

Adolescent↗
PubMed1993

Scintigraphic study of gastrointestinal transit and disintegration sites of mesalazine tablets labeled with technetium-99m.

Tablets of mesalazine covered with a pH-dependent coating (Pentacol), labeled by an original technique with technetium-99m, were administered to 12 patients, 9 with Crohn's disease, 3 of which recurrent, 1 with ulcerative colitis, and 2 with irritable bowel syndrome, with the aim of verifying in vivo the intestinal site of disintegration and how the contents spread throughout the intestine. In all cases the tablet was broken down in the distal ileum at extremely variable intervals, from 5 to 27 h, and the contents spread into the nearby loops and into the colon. The notable differences in the residence time of the whole tablet in the ileum can be explained by differences in adhesion to the inflamed mucosa and by a lower pH in the part of the ileum affected by the disease.

Adult↗
PubMed1996

Technetium-99m sestamibi scanning in multiple myeloma stem cell transplantation.

We report the use of technetium-99m sestamibi (MIBI) in a patient with multiple myeloma (MM) undergoing peripheral blood stem cell (PBSC) transplantation. MIBI is a radionuclide agent that is preferentially taken up by malignant tumors. Plain radiographs in a MM patient, taken prior to PBSC transplantation, showed a large right humeral lytic lesion that correlated with increased uptake of MIBI at the same location. MIBI uptake, demonstrating active MM bone disease, was also evident in areas which were normal on plain radiographs. Three months after PBSC transplant, the lytic lesion had healed by plain radiographs and repeat MIBI scan showed no uptake. MIBI scanning results have a positive correlation with plain radiographs, and more importantly, demonstrate active MM bone disease not yet detectable by plain radiographs. If MIBI proves more sensitive in the detection of MM bone disease than plain radiographs or bone scanning with traditional isotopes, it will have a significant role in the detection of early disease and in monitoring disease progression during and after therapy.

Aged↗
PubMed1999

Technetium-99m sulfur colloid scanning and correlative magnetic resonance imaging in patients with hairy cell leukemia and hypocellular bone marrow biopsies after 2-chlorodeoxyadenosine.

It has been observed that some patients in complete remission (CR) after 2-chlorodeoxyadenosine (2-CdA) for hairy cell leukemia (HCL) have hypocellular bone marrow biopsies despite normal peripheral blood cell counts. This discrepancy between bone marrow cellularity and peripheral blood cell counts suggests the possibility of abnormal sites of hematopoiesis. To determine sites of hematopoiesis, 11 radionuclide scans using technetium-99m (99mTc) sulfur colloid were performed in eight patients. Although no single, pattern was observed on the 99mTc sulfur colloid scans, two of the eight patients, both with virtually aplastic marrows, had multiple areas of increased uptake in the distal appendicular skeleton, suggesting abnormal sites of hematopoiesis. The same two patients had magnetic resonance imaging (MRI), which confirmed the abnormal sites of hematopoiesis.

Adult↗