99m Tc-HMPAO labelled leukocyte scintigraphy in patients with rheumatoid arthritis: a comparison with disease activity.

The aim of this study was to test the applicability of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leukocyte joint scintigraphy in the assessment of disease activity in 21 patients with rheumatoid arthritis, and to compare leukocyte scintigraphy with the Disease Activity Score (DAS), a validated activity index developed by the European League Against Rheumatism (EULAR). Twenty-one patients with rheumatoid arthritis were investigated by using 99mTc-HMPAO labelled leukocyte joint scintigraphy. The clinical and laboratory data were recorded, and the DAS was calculated and compared with the scintigraphic results in each case. A relatively high DAS score (4.71+/-1.07) was found in the majority of patients. The degree of accumulation of 99mTc-HMPAO leukocytes showed no correlation with a patient's age, gender, duration of disease, use of disease modifying anti-rheumatic drugs (DMARDs), visual analogue scale (VAS), Richie index, DAS, or any laboratory parameters. In contrast, a significant correlation was found between the global regional accumulation of the labelled leukocytes of the hands and feet, and the swollen-joint count. It is concluded that radiolabelled leukocyte scintigraphy could become one of the promising methods in the assessment of disease activity in patients with rheumatoid arthritis.     

Prediction of mortality in patients with coronary artery disease undergoing vasodilator stress testing: a comparison between 99mTc-tetrofosmin and 99mTc-sestamibi

PURPOSE: To compare the prognostic ability of the imaging agents 99mTc-sestamibi versus 99mTc-tetrofosmin to predict mortality outcomes in patients with documented coronary artery disease and undergoing vasodilator stress testing. MATERIALS AND METHODS: The study included 2147 consecutive patients who underwent rest and stress single photon emission computed tomographic (SPECT) examination with either 99mTc-sestamibi (n=1128) or 99mTc-tetrofosmin (n=1019). Information relating to all-cause death and cardiovascular death was collected over a 4-year study period. Unadjusted Kaplan-Meier estimates were compared for the two imaging agents. Cox proportional hazard models were examined to determine the incremental contribution of SPECT sum stress score (SSS) and the imaging agent after adjusting for clinical and demographic characteristics. Additionally, the interaction between SSS and agent was examined to determine if the effect of SSS on prognosis was different for the two agents. RESULTS: Vasodilator agents were used for stress testing in all patients who received 99mTc-tetrofosmin and 99mTc-sestamibi. Despite differences in patient risk factors Kaplan-Meier estimates were similar for the two groups of patients. Resulting P-values for differences between models for the end points of (1) death from any cause and (2) cardiovascular death showed that SSS combined with clinical index was significantly better than a model that adjusted for only baseline characteristics (P<0.0001 for both endpoints). The addition of imaging agent (99mTc-tetrofosmin or 99mTc-sestamibi) to the model containing both SSS and the clinical characteristics did not show further significant improvement (P=0.62, P=0.96 for death from any cause and cardiovascular death, respectively). CONCLUSION: The type of clinically available 99mTc-labelled myocardial perfusion agents did not affect interpretation of results for prognostic assessment.     

Direct comparison of technetium 99m-sestamibi and technetium 99m-tetrofosmin cardiac single photon emission computed tomography in patients with coronary artery disease

Background  Technetium 99m-labeled sestamibi and tetrofosmin tomography have shown high diagnostic accuracy in the detection of coronary artery disease (CAD). However, few data are available comparing sestamibi and tetrofosmin imaging in the same patients. The aim of the study was to determine the image quality of the two tracers and to compare the results of exercise sestamibi and tetrofosmin tomography in the same patients. Methods  The results of exercise-rest sestamibi and tetrofosmin myocardial tomography were compared in 32 patients with suspected or known CAD who underwent coronary angiography. Image quality was evaluated subjectively. Regional tracer distribution was visually assessed and quantitatively measured in 22 segments/patient. Results  At coronary angiography 7 patients had normal coronary vessels, 11 single-vessel, and 14 multivessel CAD (≥50% luminal stenosis). Image quality judged visually was comparable with the two tracers. Heart/lung and heart/liver ratios for sestamibi and tetrofosmin were not different. At visual analysis, 68% of the patients with CAD had abnormal findings with sestamibi and 76% with tetrofosmin (p=NS). At quantitative analysis, 92% of the patients with CAD had abnormal findings with sestamibi and 96% with tetrofosmin (p=NS). At both visual and quantitative analyses, sensitivity, specificity, and diagnostic accuracy in the detection of individual stenosed vessels were not different between the two tracers. Moreover, for both tracers sensitivity, specificity, and diagnostic accuracy in the detection of diseased vessels were significantly higher (all p<0.05) at quantitative compared with visual analysis. Finally, defect size and severity were similar for the two tracers. Conclusions  Exercise-rest sestamibi and tetrofosmin tomography yielded images of comparable quality and provided similar results in the identification of patients with CAD and in the detection of the individual stenosed coronary vessels.     

Exploratory study of 99mTc-EC20 imaging for identifying patients with folate receptor-positive solid tumors.

99mTc-EC20 is a folate receptor (FR)-targeted imaging agent consisting of the vitamin folate conjugated to 99mTc. FR is expressed on a variety of epithelial cancers, with advanced cancers often expressing FR at significantly higher levels than earlier stages of the disease. The goals of this pilot study were to determine the percentages of various solid tumors that accumulate 99mTc-EC20 in vivo and to correlate 99mTc-EC20 uptake with immunohistochemistry (IHC) analysis of FR expression in available biopsied tumor tissue. METHODS: A total of 154 patients with proven or suspected cancer and at least one lesion of > or =1.5 cm underwent imaging with 99mTc-EC20. The majority of these patients (77%) had a diagnosis of renal cell carcinoma. The remaining patients had a variety of other solid tumors. Whole-body planar images were obtained 1-2 h after injection, followed by SPECT of the region containing index lesions. The uptake of 99mTc-EC20 in tumors was scored as no uptake, mild uptake, or marked uptake. The resultant 99mTc-EC20 data were analyzed for correlation with the expression of the alpha-isoform of FR, as determined by IHC analysis, in tissue available from prior or subsequent surgery or biopsy. RESULTS: The administration of 99mTc-EC20 was well tolerated. Tumors with increased 99mTc-EC20 uptake were identified in 68% of patients, and IHC results were positive for the expression of the alpha-isoform of FR in 67% of patients. The agreement between methods was 61% overall (kappa = 0.096; 95% confidence interval = -0.085 to 0.277), with 72% agreement of positive results and 38% agreement of negative results. CONCLUSION: In vivo imaging with 99mTc-EC20 identified approximately two thirds of patients as having FR-positive tumors. Agreement between imaging and in vitro IHC was poor but was potentially confounded by a lack of correlation between the time of tissue sampling and the time of 99mTc-EC20 imaging, the heterogeneous expression of FR in metastatic lesions from the same patient, and the inability to detect the beta-isoform of FR by IHC. This pilot study of 99mTc-EC20 scintigraphy indicates that the agent is safe and well tolerated and that this noninvasive procedure may have utility in selecting patients likely to benefit from FR-targeted therapy.     

99mTc-interleukin-2 and 99mTc-HMPAO granulocyte scintigraphy in patients with inactive Crohn's disease

Crohn's disease (CD) is a chronic inflammatory bowel disease that may involve the whole gut. Marked intestinal T cell and macrophage activation is a key feature of the disease. Polymorphonuclear cell infiltration is also observed in the diseased gut, mainly during active inflammation. Scintigraphic detection of granulocytes and activated lymphocytes infiltrating the gut wall may be useful in identifying a subgroup of patients with clinically inactive CD who are undergoing early clinical relapse. The aims of the present study were (a) to compare the effectiveness of scintigraphy with (99m)Tc-labelled interleukin-2 ((99m)Tc-IL2) and with (99m)Tc-HMPAO labelled granulocytes ((99m)Tc-WBC) in detecting the presence and extent of bowel inflammation in patients with long-term inactive CD (>12 months) and (b) to assess the accuracy of these techniques in predicting future disease relapse. We studied 29 patients with ileal and/or colonic CD in stable clinical remission (Crohn's Disease Activity Index <150 for at least 12 months) using both (99m)Tc-IL2 and (99m)Tc-WBC scintigraphy in order to evaluate the extent of acute and chronic inflammation in the bowel. Planar and single-photon emission tomography images were acquired in each patient at 1 h p.i. For quantitative analysis of (99m)Tc-IL2 uptake, the abdomen was divided into 32 regions of interest. Despite the absence of symptoms, 18 patients (62%) showed a positive (99m)Tc-IL2 and 18 (62%) a positive (99m)Tc-WBC scan. Only 12 patients (41.4% of the total group) were positive on both scans, and the sites of IL2 and granulocyte bowel uptake were usually located in different segments, indicating that in CD, acute and chronic inflammation can be present in different sites. As far as the prognostic role of the two scans in predicting future disease relapse is concerned, both (99m)Tc-IL2 and (99m)Tc-WBC scintigraphy showed a high negative predictive value (1.00 and 0.91, respectively) but a weak positive predictive value (0.44 and 0.39, respectively). Nevertheless, Kaplan-Meier curves generated between scintigraphic findings and time free from disease relapse were statistically different only for (99m)Tc-IL2 scintigraphy (log-rank test, P=0.013). These results indicate that (99m)Tc-IL2 scintigraphy can be useful in selecting CD patients in clinical remission who could benefit from preventive therapy to avoid disease relapse.     

Synthesis and comparison of 99mTc-enrofloxacin and 99mTc-ciprofloxacin.

The use of (99m)Tc-ciprofloxacin as a tracer for infection and inflammation has been examined and discussed in the literature extensively. Its alleged ability to discriminate between sterile inflammation and bacterial versus nonbacterial infections has led to an intense debate. Other labeled fluoroquinolones might offer better characteristics or may add to a better understanding of the working mechanism of (99m)Tc-ciprofloxacin. The rationale of this work was to determine possible differences in the use of 2 labeled quinolones--that is, (99m)Tc-ciprofloxacin and (99m)Tc-enrofloxacin--as tracers for infection and inflammation in animals. METHODS: Ciprofloxacin and enrofloxacin were labeled with (99m)Tc and characterized. The stability of both preparations was evaluated in serum and in the presence of an excess of cysteine. In vitro binding studies were performed to determine the interaction of the labeled quinolones with bacteria and other cells. Rats with sterile and infectious intramuscular lesions were used to study the scintigraphic properties of the 2 compounds. To assess the specificity of binding to living bacteria, infectious intramuscular lesions of heat-killed Staphylococcus aureus and Candida albicans were used as controls. Imaging was performed with a gamma-camera at 0, 3, 5, and 22 h after injection. RESULTS: The radiochemical purity of both radiolabeled fluoroquinolones exceeded 95% as determined by instant thin-layer chromatography. Both compounds were moderately stable in serum. Binding assays did not show any saturable binding to S. aureus, heat-killed S. aureus, as well as C. albicans. None of the tracers showed specific binding to bacteria. Scintigraphy showed uptake in the infectious lesion at 1 h after injection, which washed out during the next 4 h. Abscess-to-muscle ratios for both preparations were not significantly different for the various infectious or inflammatory lesions studied and did not exceed an average of 4.25 +/- 0.62. CONCLUSION: The study demonstrated that (99m)Tc-ciprofloxacin and (99m)Tc-enrofloxacin do not show preferential binding to living bacteria. In vivo (99m)Tc-enrofloxacin has similar characteristics as (99m)Tc-ciprofloxacin except for differences in uptake in a few normal tissues.     

Identification of viable myocardium in patients with chronic coronary artery disease: comparison of thallium-201 scintigraphy with reinjection and technetium-99m-methoxyisobutyl isonitrile.

We compared the results of 201Tl reinjection and those of 99mTc-methoxyisobutyl isonitrile (MIBI) in identifying viable myocardium in 20 male patients with angiographically proven coronary artery disease (CAD) and left ventricular dysfunction (ejection fraction 30% +/- 8%). All patients had irreversible defects on standard exercise-redistribution thallium imaging. Thallium was reinjected immediately after the redistribution study, and images were reacquired. The patients also underwent stress and rest 99mTc-MIBI myocardial scintigraphy (2-day protocol). A total of 300 myocardial regions were analyzed, of which 122 (41%) had irreversible thallium defects on redistribution images before reinjection. Of the 122 myocardial regions with irreversible defects on standard stress-redistribution thallium cardiac imaging, 65 (53%) did not change at reinjection and 57 (47%) demonstrated enhanced uptake of thallium after reinjection. Of the same 122 irreversible defects on stress-redistribution thallium, 100 (82%) appeared as fixed defects and 22 (18%) were reversible on 99mTc-MIBI myocardial scintigraphy. These data indicate that 201Tl cardiac imaging with rest reinjection is superior to 99mTc-MIBI myocardial scintigraphy in identifying viable myocardium in patients with chronic CAD, suggesting that regions with severe reduction of 99mTc-MIBI uptake both on stress and rest images may contain viable myocardium.     

81mKr ventilation and 99mTc perfusion scans in chest disease: comparison with standard radiographs.

In 75 patients with various pulmonary disorders, ventilation and perfusion scans were obtained in multiple views with the 81mKr/99mTc technique and compared with an evaluation of regional ventilation and perfusion derived from the standard chest radiograph. In emphysema, the chest film correlated poorly with ventilation-perfusion scans, showing a trend to underestimate the functional impairment. In chronic bronchitis and asthma, large segmental defects observed on both ventilation and perfusion scans were associated with a normal chest radiograph. Typical findings in pulmonary embolism were segmental defects on perfusion scan with normal ventilation scan and clear lung fields on the chest film. In chronic left heart disease, plain films were inaccurate in predicting alteration of the base-to-apex perfusion gradient observed on the scan.     

Double-tracer SPECT in patients with AIDS encephalopathy: a comparison of 123I-IMP with 99Tcm-HMPAO.

Single photon emission computed tomography (SPECT) using N-isopropyl-p-(123I)iodoamphetamine (123I-IMP) and 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) was performed in 25 patients with different clinical stages of AIDS encephalopathy. The average interval between the two examinations was 7 days. In 15 of the 25 cases (60%) 99Tcm-HMPAO scans were different from 123I-IMP scans. Uptake defects of different extent were observed in 8 of 25 cases (32%), of different extent and different location in 3 of 25 cases (12%) and of identical extent but of different location in 4 of 25 cases (16%). Differences in the uptake patterns of 123I-IMP and 99Tcm-HMPAO with regard to extent and/or location were more commonly shown in patients with early acquired immunodeficiency syndrome (AIDS) encephalopathy (P = 0.0372). In this group, 99Tcm-HMPAO showed uptake defects of greater extent more frequently than did 123I-IMP (P = 0.0156). Our data indicate different brain uptake mechanisms of 123I-IMP and 99Tcm-HMPAO in early and advanced AIDS encephalopathy.     

Outcome prediction in patients at high risk for coronary artery disease: comparison between 99mTc tetrofosmin and 99mTc sestamibi

PURPOSE: To determine if there was any difference in the ability of physicians to predict prognosis with technetium 99m ((99m)Tc) sestamibi or (99m)Tc tetrofosmin in a large consecutive series of patients at high risk for coronary artery disease who underwent coronary angiography. MATERIALS AND METHODS: This study included 1,818 consecutive patients who underwent a rest and stress single photon emission computed tomographic (SPECT) examination with either (99m)Tc sestamibi (n = 915) or (99m)Tc tetrofosmin (n = 903) and cardiac catheterization. A clinical index was generated and consisted of clinical and demographic variables. Information concerning death, cardiovascular death, and nonfatal myocardial infarction was 93% complete during the 1.5-year study period. Cox proportional hazards models were generated to help determine the incremental contribution of SPECT sum stress score (SSS) and the imaging agent variable to the clinical index. RESULTS: Exercise was used for stress testing in 473 (52%) patients who received (99m)Tc tetrofosmin and 519 (57%) patients who received (99m)Tc sestamibi (P =.06). Cardiovascular death or myocardial infarction occurred in 130 patients. Resulting P values for chi(2) differences between models for the end points of (a) death from any cause, (b) cardiovascular death, and (c) cardiovascular death or myocardial infarction showed that SSS combined with clinical index was a significantly better model than adjusting for only baseline characteristics (P =.001, P <.001, P =.004, respectively). Incremental addition of either (99m)Tc tetrofosmin or (99m)Tc sestamibi to those models containing SSS and the clinical index did not show further significant improvement (P =.87, P =.88, and P =.26 for death from any cause, cardiovascular death, and cardiovascular death or myocardial infarction, respectively). CONCLUSION: This study shows that the type of clinically available (99m)Tc-labeled myocardial perfusion agents should not affect interpretation of results for risk stratification and prognostic assessment.     

Technetium-99m tetrofosmin for parathyroid scintigraphy: a direct comparison with 99mTc-MIBI, 201Tl, MRI and US

The aim of this study was to evaluate the efficacy and role of technetium-99m tetrofosmin for the detection of abnormal parathyroid glands to be referred for surgical treatment. Twenty-eight consecutive patients, including 25 primary and 3 secondary cases of hyperparathyroidism, were evaluated. ^99mTc-tetrofosmin/^99mTc-pertechnetate subtraction scintigraphy (TF/Tc) was performed on all patients, and the results were directly compared with those of ^99mTc-methoxyisobutylisonitrile (MIBI)/^99mTc-pertechnetate subtraction scintigraphy (MIBI/Tc), ²⁰¹Tl/^99mTc-pertechnetate subtraction scintigraphy (Tl/Tc), magnetic resonance imaging (MRI) and ultrasonography (US). In cases of single-gland disease, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 63.2%, 68.4%, 57.9%, 55.6% and 63.2%, respectively. In cases of multi-gland disease, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 41.7%, 41.7%, 37.5%, 58.3% and 54.2%, respectively. In cases of parathyroid adenoma, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 68.8%, 75.0%, 68.8%, 62.5% and 75.0%, respectively. In cases of parathyroid hyperplasia, the sensitivities of TF/Tc, MIBI/Tc, Tl/Tc, MRI and US were 40.7%, 40.7%, 33.3%, 53.8% and 48.1%, respectively. It is concluded that, for the detection of abnormal parathyroid glands, ^99mTc-tetrofosmin is as useful as ^99mTc-MIBI and is more useful than ²⁰¹Tl.     

Tc-99m DTPA renography in patients with collagen disease

PURPOSE: This study evaluated the use of Tc-99m DTPA renography in patients with collagen disease. MATERIALS AND METHODS: Tc-99m DTPA renal scintigraphy was performed in 28 patients with clinically diagnosed collagen disease. Twenty-two other patients who underwent renal scintigraphy and were subsequently shown to have no kidney abnormalities served as the control group. RESULTS: One quarter of the patients with collagen disease had abnormal findings of renography, despite the absence of abnormal laboratory data. Renograms were 100% sensitive for the detection of renal disease in patients with collagen disease, and their specificity was 53% when serum blood urea nitrogen, serum creatinine concentration, and proteinuria were the only measures of renal impairment considered. The glomerular filtration rate was not significantly different between the groups, but the bilateral time to peak was significantly greater in the patients with collagen disease. Hydronephrosis was present in 7% of patients with collagen disease. CONCLUSION: Renography is useful for detecting early changes of renal involvement when the clinical state of collagen disease is evaluated.     

Initial stage of Legg-Calve-Perthes disease: comparison of three-phase bone scintigraphy and SPECT with MR imaging.

Twenty-one patients with initial stage Legg-Calve-Perthes (LCP) disease were examined by three-phase bone scintigraphy, single photon emission scintigraphy (SPECT), and magnetic resonance (MR) imaging. On dynamic study, increased activity was present in the epiphysis or the growth plate in 39%; the corresponding figure for blood-pool images was 94%. Pinhole images demonstrated the lateral stripe of revascularization in 57% of patients. Decreased signal intensity in the epiphysis on T1-weighted images proved to be the most sensitive indicator of epiphyseal necrosis on MR imaging and was absent in only 10% of the cases. The subchondral fracture occurred in 62% (including the above 10% of cases), identified by T1-weighted image. Cartilaginous hypertrophy, detected by T1-weighted image, had a high incidence (81%). Joint effusion was identified on T2-weighted images in 90% of patients. The cross-sectional views provided by SPECT and MR imaging permits a better appreciation of the extent of epiphyseal necrosis in LCP disease.     

Clinical experience with Tc-99m MIBI imaging in patients with malignant tumors. Preliminary results and comparison with Tl-201.

Tc-99m MIBI imaging was performed in 34 patients with histopathologically proven malignant tumors. The study was performed in two steps. In the first step, only Tc-99m MIBI imaging was performed (Group 1). In the second step, both Tc-99m MIBI and Tl-201 imaging were performed for comparison (Group 2). Seventeen patients were studied in each step. The size of the smallest primary tumor (breast cancer) was 15 x 10 mm, and that of the largest (lung cancer) was 145 x 130 mm. Of the 34 patients, 26 showed Tc-99m MIBI uptake at the tumor site. In Group 1, 12 patients showed Tc-99m MIBI tumor uptake, but no uptake was detected in five patients (squamous cell carcinoma of the esophagus, teratoma of the testis, nonHodgkin's lymphoma, and squamous cell carcinoma of the lung). In Group 2, 13 patients showed both Tc-99m MIBI and Tl-201 uptake at the tumor site, but one patient with breast cancer showed only Tc-99m MIBI uptake, and three patients showed no Tc-99m MIBI and Tl-201 uptake (embryonal cell carcinoma of the testis, hepatocellular carcinoma). The overall sensitivity of Tc-99m MIBI imaging was 76.4%. In Group 2, the sensitivity was 82.3% for Tc-99m MIBI and 76.4% for Tl-201. Our preliminary clinical experience suggests that Tc-99m MIBI can be helpful in localizing malignant tumors and that its sensitivity is slightly higher than Tl-201.     

Clinical comparison of bone scintigraphy with 99Tcm-DPD, 99Tcm-HDP and 99Tcm-MDP

The bone-imaging agents MDP, DPD and HDP were compared radiochemically (only minor differences were found) in 12 patients with prostatic and 12 patients with breast carcinoma. Each patient received both MDP and either DPD or HDP. The scintigraphic examinations were compared visually and quantitatively. The uptake ratio normal bone/soft tissue was higher for DPD and HDP than for MDP. The ratio pathologic bone/normal bone was highest for MDP, particularly for prostatic carcinoma. The differences in this ratio for breast carcinoma were in general non-significant. The observed differences were minor and of little practical importance.     

Bone lesion detection with carrier-added 99mTc-EDTMP in comparison with 99mTc-DPD

An increased uptake of bone-seeking radiopharmaceuticals into malignant bone lesions could further improve the diagnostic accuracy of routine bone scanning. The tracers used in clinical routine for bone scanning are methylene-diphosphonate (MDP), dicarboxypropane-diphosphonate (DPD) and ethylenediaminetetramethylene-phosphonate (EDTMP). MDP and DPD are usually labelled with 99mTc for diagnostic use, whereas EDTMP is labelled with 153Sm for therapeutic purposes. This study aimed to compare, for the first time, bone scanning with an improved preparation of 99mTc-EDTMP (by the addition of rhenium) (carrier-added) with 99mTc-DPD. Twenty malignant bone lesions were investigated in 10 patients. The ratios of bone lesion to soft tissue (BL/ST) and of bone lesion to normal bone (BL/NB) were compared 3 h after the injection of either compound. Quantitative analysis demonstrated a significant (P<0.05) difference in BL/ST ratio in favour of 99mTc-DPD. The BL/NB ratio was not significantly different. Visual image analysis resulted in a clinically comparable interpretation of imaging studies with the use of 99mTc-DPD and carrier-added 99mTc-EDTMP. These preliminary data support the concept of carrier addition to increase bone uptake by the modification of the complex structure of 99mTc-EDTMP. However, any advantage over conventional 99mTc-based tracers for bone scintigraphy in clinical use needs to be demonstrated in controlled trials.     

Orbital scintigraphy with the somatostatin receptor tracer 99mTc-P829 in patients with Graves' disease.

Receptors for somatostatin (SST) (SSTR) are expressed on various tumor cells as well as on activated lymphocytes. Previous data have shown that (99m)Tc-P829 binds with high affinity to many different types of tumor cells as well as to leukocytes via the human hSSTR2, hSSTR3, and hSSTR5 target receptors. Consequently, (99m)Tc-P829 was successfully introduced as a peptide tracer for tumor imaging. In this study, we evaluated the orbital uptake of (99m)Tc-P829 in patients with active and inactive thyroid-associated orbitopathy (TAO), accompanied by lymphocyte infiltration in the acute stage and by muscle fibrosis in the chronic stage of the disease. METHODS: To evaluate its clinical usefulness in Graves' disease, (99m)Tc-P829 scintigraphy (approximately equal to 740 MBq) was performed in 44 patients with TAO (median duration, 19 mo; range, 1-360 mo). The clinical activity of the orbital disease was graded by the NOSPECS (no signs or symptoms; only signs, no symptoms; signs only; proptosis; eye muscle involvement; corneal involvement; sight visual acuity reduction) classification of the American Thyroid Association, the clinical activity score (CAS), and the superonasal index (SNI). SPECT (360 degrees ) and planar studies were completed within 3 h after injection. Orbital (O) regions of interest (ROIs) were compared with temporoparietal and occipital (OCC) ROIs. Orbital uptake ratios in Graves' disease were compared with data obtained from lung cancer patients with no eye disease (n = 22). RESULTS: Overall, (99m)Tc-P829 biokinetics were the same in Graves' disease patients as in lung cancer patients, showing a rapid blood clearance and visualization of the facial bones within minutes of injection. In all control patients, the orbit appeared as a "cold area," whereas visual orbital accumulation of (99m)Tc-P829 was found in patients with active TAO (O/OCC ratios: 1.26 +/- 0.04 vs. 1.69 +/- 0.04; P < 0.01, respectively). Patients with active eye disease (n = 25) presented with an increased orbital uptake of (99m)Tc-P829 compared with patients with inactive disease (n = 19; O/OCC ratio: 1.12 +/- 0.05; P < 0.01). A statistically significant correlation was found between CAS and the orbital uptake (O/OCC ratio) values (r = 0.90), whereas no correlation could be documented regarding the NOSPECS classification as well as the SNI. CONCLUSION: In TAO, (99m)Tc-P829 yields high orbital binding with good clinical correlation. The better image quality due to the high energy of technetium, the lower radiation dose for patients and personnel, and the short acquisition protocol favor SSTR scintigraphy with (99m)Tc-P829 over (111)In-labeled compounds. The in-house availability of the radiotracer and cost-effectiveness are further advantages.     

A clinical comparison of 99mTc-diethyl-iminodiacetic acid, 99mTc-pyridoxylideneglutamate, and 131I-rose bengal in liver transplant patients.

The relative merits of three radiopharmaceuticals for evaluating liver transplant patients were determined in paired studies. In 86% of studies both 131I-RB and 99mTc-PG gave similar information for differentiation of hepatocellular disease and billary tract obstruction. 99mTc-PG probably demonstrates the biliary tract and small intestine better early after injection (8%); 131I-RB is probably better in showing the colon at 24 hours when intestinal activity is not seen by 1 hour (6%). 99mTc-diethyl-IDA is superior in all respects when compared to 99mTc-PG. The blood retention method (20 min./5 min.) showed that none of the radiopharmaceuticals was a reliable indicator of hepatocyte function when compared to total serum bilirubin.