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The value of Tc-99m HEDP bone scintigraphy as a means of detecting uremic pulmonary calcification was studied in 30 chronic dialysis patients. A high incidence of currently recognized predisposing factors for metastatic calcification was found and calcification was recorded at other sites. Scintigraphy was performed after reducing background activity by hemodialysis to levels found in normals. From chest images and chest-to-spine activity ratios, evidence of pulmonary calcification could be obtained in only one patient, and subsequent histologic examination revealed extensive calcification. High chest-to-spine activity ratios suggested increased pulmonary radionuclide uptake in several other patients, but these findings were not conclusive. These results indicate that uremic pulmonary calcification--which, according to autopsy studies, develops in about 60-75% of dialysis patients--cannot be detected with bone-seeking radiopharmaceuticals, unless the calcification is severe. This is probably due to the unusual crystalline and chemical composition of uremic pulmonary calcification.

The purpose of this study was to determine the reliability of the measured left ventricular ejection fraction (LVEF) and wall motion analysis by the recently introduced quantitative electrocardiographically (ECG)-gated myocardial perfusion single-photon emission computed myocardial tomography technique (gated SPECT) (QGS).We compared technetium-99 m tetrofosmin gated SPECT imaging and contrast ventriculography in the assessment of global and regional left ventricular function in 74 patients with undiagnosed chest pain of whom 27 sustained a previous myocardial infarction.Linear regression analysis demonstrated that gated SPECT determined LVEF correlated well with LVEF determined from contrast ventriculography (y = 0.95x + 1.9, r2 = 0.84, p0.0001). Bland-Altman plot analysis showed no systematic difference between the two sets of values derived from the two imaging approaches over a wide range of LVEF values. Exact agreement of segmental wall motion scores was 460 of 518 (89%) segments with a kappa value of 0.76 (p0.0001).We conclude that gated SPECT imaging is an accurate and reliable clinical tool to accurately measure global and regional left ventricular function.

In patients with limited disease SCLC, the overall survival is still poor. Therefore, a retrospective study was performed involving 48 patients with limited disease SCLC to select a parameter which can identify prognostic subgroups at the time of diagnosis.Follow-up ranged from 3 to 96 months, during which period 38 patients died. Based on clinical outcome, patients were classified into 3 groups: complete remission (CR) (n = 16), local recurrence (LOC) (n = 7) and distant recurrence (DIS) (n = 25). Age, gender and pretreatment biochemical parameters were correlated with clinical outcome and survival. For survival 70 patients staged as having extensive disease (ED) served as a control group.No differences in survival were found in patients with LOC (14% 2 year survival) and DIS (16% 2-year survival) (p = 0.67). Patients achieving a complete remission had a significantly better survival (75% two-year survival). LDH was found to be the only significant correlate of both tumor progression and survival. All patients with pretreatment LDH levels240 U/L (n = 13) had tumor recurrence. The survival rate of patients with LDH levels, 240 U/L (41% 2-year survival) was much better than that of patients with LDH levels240 U/L 8% 2-year survival) (p = 0.0001). No significant difference in survival (p = 0.33) was found between patients with LD and LDH240 U/L and patients with ED and LDH400 U/L. Patients with ED and LDH values400 U/L showed the poorest outcome.LDH may be used for the identification of prognostic subgroups in SCLC. Patients showing pretreatment LDH levels240 U/L have an extremely high risk of tumor recurrence, while their survival is poor and comparable to that of patients staged as having extensive disease and LDH values400 U/L.

A head-to-head comparison between 99mTc-sestamibi SPECT and planar myocardial imaging using dipyridamole low-level exercise stress was performed for the assessment of coronary artery disease (CAD) and for the impact on patient management in 78 patients (pts) who underwent coronary arteriography. Overall sensitivity and specificity for detection of CAD were 82% and 82% for SPECT, and 78% and 73% for planar imaging, respectively (both NS). Compared to planar imaging the sensitivity of SPECT imaging was significantly higher for detecting left anterior descending (p = 0.02) and left circumflex (p = 0.03) coronary artery disease. In predicting distally located stenoses, SPECT was significantly superior to planar imaging for the left circumflex artery (p = 0.025). Concordance analysis of perfusion status showed agreement in 308 of 390 (79%) of coronary flow regions both with respect to the presence or absence of perfusion and to the reversibility or irreversibility of defects (kappa = 0.60, SE 0.04). Stress-induced perfusion defects were significantly more detected by SPECT than by planar imaging (p0.001). Based on SPECT findings 31 pts were proposed for revascularization compared to 30 pts based on planar imaging (NS). Overall there was agreement in 65 (83%) pts regarding treatment strategy. We conclude that in a head-to-head comparison SPECT provided improved diagnostic value compared with planar imaging. However, with respect to patient treatment, the superiority of SPECT was not always translated into improved patient management.

Aim of the study was to evaluate [99mTc]hexamethyl-propylamine-oxime (HMPAO) leukocyte scintigraphy for the assessment of disease activity and extent in inflammatory bowel disease patients. Results and scores of scintigraphy using [99mTc]HMPAO-labeled leukocytes were retrospectively compared with the activity index of van Hees, laboratory parameters, and gastroenterologists' assessment of disease using endoscopy, radiology, and histology plus clinical parameters in 136 patients with Crohn's disease (115) and ulcerative colitis (21) and in 29 controls. There were 114 positive and 22 negative [99mTc]HMPAO leukocyte scintigrams. Sensitivities for active disease at 1 and 3 hr were 98% and 98% and specificities were 100% and 83%, respectively. [99mTC]HMPAO leukocyte scintigraphy is superior to the activity index and the gastroenterologists' clinical assessment of active inflammation in IBD patients. Scintigraphy allows assessment of the existence, extent, and intensity of active inflammation in IBD patients in one examination with high accuracy.

Reinjection of thallium-201 (201Tl) improves the detection of myocardial ischaemia in approximately 50% of irreversible defects present on 3 h redistribution images. Additional reinjection studies, however, may limit the capacity of the nuclear laboratory and they are not patient-friendly Previous studies have suggested that only severe persistent defects with less than 50% of maximal 201Tl uptake are irreversibly damaged, with little chance of recovery following coronary artery bypass grafting (CABG). We examined the ability of a modified stress-reinjection protocol without redistribution imaging to predict subsequent improvement in myocardial perfusion post-CABG. Thirty-seven patients underwent quantitative planar stress/3 h reinjection 201Tl scintigraphy before and after uncomplicated CABG. After stress, segments were classified as normal (or = 75% maximum 201Tl uptake), moderate defect (50-75%) or severe defect (50%). After reinjection, they were classified as completely normalizing (or = 75%), partially improving moderate defect (increaseor = 10% but75%), partially improving severe defect (increaseor = 10% but50%), persistent moderate defect (10% increase) or persistent severe defect (50% initial uptake with10% increase). Scintigraphic classification was compared with left ventricular wall motion and post-operative classification. Of 336 initial stress defects, 264 (79%) were moderate defects and 72 (21%) were severe defects. After reinjection, 146 (55%) moderate defects normalized, 25 (9%) improved partially and 93 (35%) persisted. Nineteen (26%) severe defects normalized, 33 (46%) improved to become moderate defects, 7 (10%) improved only slightly and 13 (18%) persisted. Post-CABG, 201T1 uptake was normal in 123 of 146 (84%) completely normalizing moderate defects, 15 of 25 (60%) partially improving moderate defects, 53 of 93 (57%) persistent moderate defects, 11 of 19 (58%) completely normalizing severe defects and 13 of 33 (39%) partially improving moderate defects. None of the partially improving severe defects or persistent severe defects normalized. The sensitivity and specificity of detection of viability with pre-CABG stress-injection scintigraphy were 66% and 72% respectively, with pre-CABG wall motion 80% and 40% respectively, whereas in combination they resulted in a sensitivity and specificity of 94% and 70% respectively. We conclude that stress/3 h reinjection without redistribution imaging is a clinically feasible method for predicting myocardial 201T1 uptake post-CABG. The severity of defects and the pattern of change of uptake after stress-injection are related to the likelihood of normal 201T1 uptake post-CABG. Severe defects after reinjection are very unlikely to recover.

To determine effectiveness of technetium-99m labelled polyclonal human immunoglobulin G (99mTc-IgG) scintigraphy to monitor variation in arthritis activity in patients with rheumatoid arthritis (RA).The results of semiquantitative 99mTc-IgG scintigraphy were compared with those of examination before and 26 weeks after initiation of parenteral gold treatment in 19 patients with RA.Clinical and laboratory variables of arthritis activity as well as the scores of 99mTc-IgG scintigraphy were significantly lower after gold treatment compared to the scores before treatment. However, the difference between the mean scores of 99mTc-IgG scintigraphy before and after treatment was statistically significant for more joints than such difference in scores for joint pain and joint swelling.99mTc-IgG scintigraphy is able to reflect variations in arthritis activity in patients with RA.

This study addressed the following questions: How does 99mTc-IgG scintigraphy compare to physical examination in the detection of synovitis as determined histologically, and is 99mTc-IgG scintigraphy a sensitive detector of histologically documented synovitis activity in the absence of clinically detectable knee joint swelling?The results of measuring synovitis activity by physical examination and by scintigraphy with technetium-99m labelled polyclonal human immunoglobulin G (99mTc-IgG) were compared with the results of histological examination of synovial biopsies taken from the knee joints of patients with rheumatoid arthritis (n = 21), osteoarthritis (n = 9) and various other rheumatic diseases (n = 10).The sensitivity of 99mTc-IgG scintigraphy in detecting synovitis activity, as determined histologically (85%), was higher than the sensitivity of joint swelling (65%). In the absence of clinically detectable knee joint swelling the sensitivity of 99mTc-IgG scintigraphy was 83%.This study shows that 99mTc-IgG scintigraphy is a more sensitive method than physical examination in detecting histologically documented synovitis activity.

In this article clinical examples of extraskeletal localization of technetium-99m (99mTc)-labeled diphosphonate are described. In several of these cases this finding was relevant for clinical decision-making. 99mTc-labeled diphosphonates have been used for skeletal imaging since 1971, and from 1973 on many reports of extraskeletal localizations of these agents have been published. This visualization can be due to (1) an abnormality of the excretory route of 99mTc-labeled diphosphonate or (2) increased uptake in pathologically altered tissues and organs. The latter has been recorded in a multitude of disease processes, such as ischaemic injury, inflammatory processes, benign or malignant neoplasms, non-skeletal metastases, malignant pleuritis, scars, radiation injury and amyloidosis. Although the precise mechanism of extraskeletal uptake of 99mTc-labeled diphosphonate remains uncertain, binding of this radiopharmaceutical to calcium-containing compounds is thought to play a critical role.

Application of the Thallium-201 quantitative analysis method to Tc-99m Sestamibi planar myocardial perfusion images results in oversubtraction of tissue crosstalk, defined as 'activity within the myocardial image, which originated outside the heart'. A modified algorithm, specific for Tc-99m Sestamibi, was applied in 60 patients and the results of quantitative analysis to estimate the risk of coronary artery disease were compared with coronary angiographic findings and with visual analysis. New crosstalk planes were generated based on the results in 20 male healthy volunteers. The results in our study group indicate a higher diagnostic accuracy when circumferential profiles are generated on the basis of maximal counts compared to mean counts. Quantitative analysis was able to predict the presence or absence of CAD as accurately as visual analysis. Odds ratios were 1.07 and 1.32 respectively (P0.001) for both quantitative maximal uptake and visual uptake analysis. Sensitivity of visual analysis alone was 89%, increasing to 96% with combined visual/quantitative analysis. Specificity of visual analysis decreased from 79% to 64% with combined analysis. Although only minor differences are seen, the maximal count uptake profiles were found to have additional diagnostic value compared to visual analysis alone.

A gamma camera was equipped with a special collimator and arm assembly for bone mineral measurements with dual photon absorptiometry (DPA). The system was evaluated in vitro and in vivo and compared both with a rectilinear DPA and a dual energy X-ray (DEXA) system. All 3 systems showed a linear response in measurements of 4 vials, containing different amounts of hydroxyapatite. Phantom measurements with the gamma camera system showed a precision of 1.6% to 2.8%. Results obtained in 8 healthy volunteers with rectilinear and gamma camera systems were well correlated (R2 = 0.78). With the photon beam directed from posterior to anterior, the separation of vertebrae was easy with the gamma camera system. We conclude that bone mineral measurements can be made with a gamma camera for assessment of fracture risk and in the decision process whether a patient needs treatment or not. For follow-up, the precision of DPA with a gamma camera is inadequate.

Bone mass measurements were performed in a group of 30 ambulant, non-steroid treated female patients with rheumatoid arthritis (RA) of relatively short duration (mean 4.9 years). The bone mineral density (BMD) of the lumbar spine and femoral neck was assessed by dual-energy x-ray absorptiometry (DEXA), and related to parameters of disease activity and severity. Lumbar BMD was within the range of normal while femoral BMD was decreased compared to age-matched controls. BMD values, expressed as the percentage of age-matched healthy controls (BMD%), were positively related to the body mass index and negatively related to the number of swollen joints, the erythrocyte sedimentation rate and the platelet count. No relation was found between the lumbar and femoral bone mass on the one hand and disease duration, number of disease modifying anti-rheumatic drugs ever used, Ritchie articular index, C-reactive protein, functional ability or radiological scores on the other. It is concluded that in ambulant non-steroid treated female RA patients lumbar bone mass as measured with DEXA is within the range of normal, while femoral bone mass is slightly reduced. Both lumbar and femoral bone mass are related to the body mass index and parameters of disease activity.

In a prospective comparative study of 14 patients with inflammatory bowel disease (IBD), the abilities of 99mTc-HMPAO labeled white blood cells (WBCs) and 111In-granulocytes to assess the presence and location of active disease were compared. The two examinations were carried out within 2 wk of each other. Scintigraphically concordant positive or discordant segments were evaluated by radiologic or endoscopic examination performed within 14 days. When bowel segments were compared, concordance was found for 102/111 (91.8%) segments between 99mTc-WBC images obtained at 1 hr after injection and 3-hr 111In-granulocyte images. For five of five 99mTc-WBCs positive/111In-granulocyte negative segments, it could be proven that the 99mTc-WBC result was caused by active disease. For patients, 99mTc-WBC scintigraphy detected four more patients with active disease than 111In-granulocytes (11 and 7 patients, respectively). Technetium-WBCs was superior in the assessment of active disease, especially for small bowel segments. We conclude that early imaging 1 hr after the injection of 99mTc-WBCs can reliably replace 111In-granulocyte scintigraphy in IBD patients because the radiopharmaceutical is available on a daily basis. Thus, there is less radiation burden to the patient and cell separation is simpler and less time-consuming.

Thallium-201 reinjection following 3-4-hr redistribution imaging improves the detection of viable myocardium but considerably prolongs the total investigation time. We compared the results of immediate 201Tl reinjection with 3-hr redistribution imaging in 120 consecutive patients who were evaluated for myocardial ischemia. Thallium-201 was reinjected immediately following the postexercise study. The images were acquired 1 hr later and reacquired at 3 hr redistribution. A total of 960 segments per imaging series were evaluated, of which 320 (33%) segments showed perfusion defects on the post-exercise images. On the 1-hr images, 220 (69%) segments demonstrated enhanced thallium uptake, 97 (30%) segments did not change and 3 (1%) segments showed reverse redistribution. Of the 100 (97 + 3) persistent defects, only 12 (4%) segments showed fill-in of 201Tl on 3 hr redistribution images. A total of 49 (15%) segments showed reverse redistribution. Defects on postexercise images were seen in 95 patients (79%) of whom 9 (10%) showed no change on immediate reinjection images. In only 1 (1%) patient was the diagnosis changed from myocardial necrosis to myocardial ischemia after analysis of the 3-hr redistribution images. These data indicate that immediate postexercise reinjection of 201Tl followed by 1-hr image acquisition may be superior to 3-hr redistribution imaging in identifying viable myocardium in patients evaluated for myocardial ischemia. This protocol eliminates the need for an additional series of 3-4-hr redistribution images and offers the advantages of reduced total imaging time, improved convenience for the patient and increased patient throughput.

The ability of 99mtechnetium labelled nonspecific, polyclonal human immunoglobulin G (99mTc-IgG) scintigraphy to depict and quantify synovial inflammation was studied in 30 patients with rheumatoid arthritis (RA). All patients were injected with 350 MBq 99mTc-IgG and imaging was performed 4 h later. This resulted in excellent images of inflamed synovium. Scores for 99mTc-IgG joint scintigraphy correlated highly with scores for joint swelling and C-reactive protein levels, weakly with pain scores and not with radiographic scores of joint destruction. These results suggest that 99mTc-IgG joint scintigraphy may provide an objective test to detect synovitis and measure the activity of the disease.

There is a need for an easily prepared radiopharmaceutical agent for the detection of inflammation and infection. In a group of 14 patients with inflammatory bowel disease (IBD), the detection of actively involved intestinal segments by nonspecific human polyclonal immunoglobulin (IgG) labeled with 99mTc was compared with that of 111In granulocytes. To determine the specificity of 99mTc-IgG scintigraphy, 8 control patients without clinical indications of intestinal inflammation were examined. 99mTc-IgG was found in the left colon in 8 and in the right colon in 7 of the 8 controls 4 hours after the injection. At that time of scintigraphy only 4 IBD patients exhibited a more intense accumulation at the site of the intestinal segments with active disease. In contrast, in a randomized comparison with 111In granulocytes scintigraphy was positive in 11 patients with the latter technique. Moreover, fewer diseased segments were seen in the 4 patients with positive 99mTc-IgG scintigraphy (6 versus 12 with 111In granulocytes). In view of the low sensitivity and specificity, it is concluded that 99mTc-IgG is not suitable for the scintigraphic staging of IBD patients.

We studied the cases of eleven patients in whom a rotationplasty had been done after wide resection of the distal part of the femur. All patients had had a malignant tumor of bone, but none had the complication of edema or leakage of lymph after the rotationplasty. We made lymphoscintiscans soon after the operation in four patients and weeks or months later in all eleven patients. There was a delay in the flow of lymph in three of the four patients who were examined lymphoscintigraphically soon after the operation and there was obstruction of flow in the fourth patient, but there was evidence of a decreased rate of flow in only two of the eleven patients at the time of the later examination.

The diagnostic value of immediate post-exercise left ventricular ejection fraction (LVEF) was assessed in 161 patients at rest, during maximal exercise, and immediately post-exercise by radionuclide angiography. Fifteen patients had a second examination, giving a total of 176 radionuclide examinations. Additionally, the correlation between post-exercise LVEF and physical validity was investigated. Sixty-one patients (35%) with a recent myocardial infarction (less than 4 weeks), 66 patients (37%) with an old myocardial infarction (greater than 4 weeks), and 21 patients (12%) with valvular lesions were studied. Twenty-eight patients (16%) with an abdominal aneurysm were considered as controls based on history and a normal resting and exercise electrocardiogram (ECG). LVEF and a cumulative regional wall motion (RWM) score for three regions were obtained. LVEF post-exercise was significantly increased compared to LVEF at maximal exercise in all four diagnostic groups. Absolute LVEF values were significantly dependent on the level of exercise. We conclude that immediate post-exercise LVEF should not be used for separating patients with and without coronary artery disease.

Mutant frequencies were measured in T-lymphocytes of patients undergoing radionuclide angiography with erythrocytes labeled in vivo with technetium-99m. Blood from 13 patients was sampled before and after (8-120 days) an injection with 750 MBq technetium-99m. Frequencies of HPRT- mutants were measured with the T-cell cloning method. Results indicated that the mean frequency of mutants after treatment was significantly below that measured before exposure. Thus, in contrast to published data, our results do not support the conclusion that radionuclide angiography with technetium-99m induces HPRT- mutations. Further analysis of our data indicated that the decrease in mutant frequency after exposure can be accounted for by an effect of cloning efficiency.

Serum concentrations of IgG may influence Fc receptor-mediated clearance of immune complexes. For instance, when 123I-labeled aggregates of human IgG (123I-AIgG), used as a model for soluble immune complexes, are administered to patients with systemic lupus erythematosus (SLE), there is an inverse correlation between the serum concentrations of IgG and the clearance and volume of distribution in steady state (Vss) of 123I-AIgG. To answer the question whether IgG has a direct effect on the clearance of immune complexes, we measured the elimination of 123I-AIgG in eight patients with hypogammaglobulinemia, before and after substitution with intravenous gammaglobulin (IVIG). As expected, raising IgG concentrations in these patients (by 6 g/l) caused a significant decrease of the Vss of 123I-AIgG. However, clearance of 123I-AIgG remained unchanged by IVIG. Thus, the results of this study offer no experimental evidence that raising concentrations of IgG influences the clearance of soluble immune complexes.

The estimation error due to variations in soft-tissue baseline in lumbar bone mineral content (BMC) measured by dual-photon absorptiometry (DPA) was calculated with a new method of automatic baseline subtraction. In water phantom measurements, the s.d. of the soft-tissue (ST) baseline matched closely (r = 0.98) to the random error, calculated using 44 keV and 100 keV count rates and the directly determined baseline variations. In 21 volunteers and in 70 patients with osteoporosis, the ST variations were larger than the expected random error, revealing a source of error related to the inhomogeneity of soft tissue. The estimation error in BMC caused by ST variations was 0.7% in healthy subjects (mean BMC 40.5 gHA) and 1.5% in patients (mean BMC = 26.4 gHA). These results indicate that ST-related errors are an important limit to the precision of lumbar DPA measurements.

While studying the uptake of iodine-123-metaiodobenzylguanidine ([123I]MIBG) in chemodectomas, we coincidentally detected catecholamine secreting tumors in 5 out of 14 patients. In three of these cases, a norepinephrine secreting abdominal paraganglioma was subsequently removed. One patient had a norepinephrine secreting chemodectoma and one had a dopamine secreting chemodectoma. Prior to [123I]MIBG imaging and urinary catecholamine measurements, endocrine activity was suspected in only one of these five patients. Apart from these five cases, two other patients showed elevated catecholamine secretion and abnormal abdominal [123I]MIBG concentrations. However, these two patients were not surgically explored, because of normal computed tomography (CT) and magnetic resonance (MRI) studies. We suspect that catecholamine-secreting tumors are more common in patients with chemodectomas than is assumed in the literature, and we therefore recommend urinary catecholamine screening for all patients with chemodectomas. In case of elevated catecholamine secretion, MIBG scintigraphy is indicated.

Indium-111 autologous leucocyte scanning is a non-invasive and reliable technique for the detection of abdominal abscesses. In the past decade several papers have been published concerning the use of this technique in the assessment of inflammatory bowel disease (IBD) with variable results. We conducted a prospective study of 62 patients with IBD attending the Leiden University Hospital, to assess the diagnostic value of indium-111 tropolonate autologous granulocyte scanning. Fifty-one patients had Crohn's disease (CD) (30 with involvement of the small bowel, 18 the colon only, and 3 patients had both localizations), and 11 had ulcerative colitis (UC). Twenty-one of 26 patients with evidence of active disease of the small intestine had a true-positive scan (sensitivity, 80%). However, accurate assessment of localization and extent of disease were often difficult. The other five patients had a false-negative scan. Seven patients had a true-negative scan. No false-positive scans were found. Thus, the diagnostic accuracy for small-intestinal Crohn's disease was 85%. In contrast, of 32 patients with colonic disease (CD and UC), 26 had a true-positive scan corresponding in localization and extent with standard investigations, 3 patients had a false-negative scan (sensitivity, 90%), and 3 had a true-negative scan (diagnostic accuracy, 91%). The patients' acceptability of this procedure was definitely superior to that for radiology and endoscopy. In conclusion, this technique has a definite place in evaluating localization and extent of active colonic disease and in severely ill patients in whom invasive techniques are contraindicated.(ABSTRACT TRUNCATED AT 250 WORDS)

Following a report on the use of Tc-99m-diethylenetriamine pentaacetic acid (Tc-99m-DTPA) for detection of malignant breast tumors we compared this method with other diagnostic aids such as mammography and cytology. Among 160 women referred to our department for diagnosis, 166 examinations were performed (six patients had bilateral lesions); the final diagnosis of the breast lesion was established as malignant in 62 cases and benign in 104 cases. The scintigraphic image was reported malignant if an area of focal uptake observed on the scan 30 minutes after injection of the tracer persisted or became more intense on the 2-hour scintigram. All other uptake patterns were considered benign. For this examination we obtained a sensitivity of 75% and a specificity of 91%. For mammography, sensitivity was 90% and specificity was 82%. The lower false-positive results of scintigraphy may serve to confirm the benignancy of doubtful mammographic findings, for when both examinations suggest a benign lesion, the combined imaging procedure is a useful means of excluding cancer (sensitivity 96%, predictive value 98%). It is concluded that in all other cases Tc-99m-DTPA breast scintigraphy is of limited value.

Gallbladder concentration of 131I-iodocholesterol was observed in a patient studied for localization of adrenal activity. Misinterpretation of gallbladder activity as right adrenal function is possible if a lateral view is not obtained. The exposure of gallbladder mucosa may occasionally be far higher than the remainder of the biliary tract.

A prospective pilot study on immunoscintigraphy with monoclonal antibody fragments against cutaneous melanoma (MoAb 225.28S) was performed in 17 patients with a clinical diagnosis of choroidal melanoma. Monoclonal antibodies against melanoma associated antigen were labelled with 740 mBq (20 MCi) of the radionuclide 99mTc and injected intravenously. Images were made with a gamma camera 6 hours after injection. With a double pinhole collimator radioactivity was counted thrice in both eyes 6 hours after injection. In 6 out of 17 patients (35.3%) the melanoma could be imaged with the gamma camera. With the double pinhole collimator a significantly higher activity was measured in the melanomatous eye in 13 out of 17 patients (76.5%). In four patients a false negative result was obtained. Considering these results immunoscintigraphy may be valuable in ocular melanoma diagnostics but its specific value still has to be assessed.

A right-sided position of the heart in the chest in situs solitus is an abnormal feature easily discernible from a plain chest radiograph. This cardiac malposition may be due to cardiac displacement (dextroposition), which is usually a feature of lung disease, or a structural abnormality of the heart (dextrocardia). Because each condition has different clinical pathologic implications, it is important to distinguish them. Chest films, however, often provide no conclusive information. We performed radionuclide angiocardiography (RNA) in six adults with a cardiac malposition in situs solitus. It was found that morphologic data obtained from the serial images may distinguish dextroposition from dextrocardia. In addition, these images permitted us to diagnose congenitally corrected transposition, a cardiac anomaly which occurs with increased frequency in situs solitus with dextrocardia. Quantitative shunt detection performed during this procedure is helpful in the differential diagnosis of dextroposition and able to distinguish uncomplicated dextrocardia from dextrocardia associated with other cardiac abnormalities. RNA therefore is a valuable and easily performed method in the analysis of cardiac malpositions in adults.

In the present study, we tested mononuclear phagocyte system function in nine healthy controls and 15 SLE patients with complement activating 123I-labelled aggregates of human IgG (AIgG). Clearance half-time of AIgG was 26 +/- 8 min in controls, compared to 58 +/- 27 min in patients (P less than 0.005). Binding of AIgG to erythrocytes was significantly lower in patients, 9.3 +/- 8.1 vs 24 +/- 20% (P less than 0.05). The increase of C3a-levels in plasma was significantly lower in patients than in controls (P less than 0.05 at 3 and 8 min), suggesting less complement activation. Liver and spleen uptake of 123I-AIgG was measured with a gamma camera and expressed as liver/spleen uptake ratios. In patients, the liver/spleen uptake ratios were significantly higher than in controls at 15 min, 3.8 +/- 2.0 vs 2.31 +/- 0.7 (P less than 0.05), due to less splenic uptake of AIgG. Correlations between clearance half-time or liver/spleen uptake ratios and immune complex levels or disease activity were not found. This study indicates that clearance of soluble AIgG is abnormal in patients with SLE, due to decreased splenic uptake of AIgG.

Bone scintigraphy with Tc-99m HEDP was performed in 30 patients on maintenance hemodialysis, and the results of quantitative analysis were compared with those of a normal group. To permit this comparison, elevated background activity due to the absence of renal radiotracer excretion was reduced by hemodialysis to levels found in the normals. Histologic proof of renal osteodystrophy had been obtained in all patients. The incidence of radiographic abnormalities was 46%, whereas abnormal scans were found in 25 patients (83%); skeletal lesions were also more pronounced and detected earlier. However, even when the scans appeared normal, the quantitative analysis showed increased skeletal activity in all patients. The total skeletal activity proved to be a good index of the severity of renal osteodystrophy and appeared dependent on both osteomalacia and hyperparathyroidism. These findings show that bone scintigraphy is a sensitive method to detect skeletal involvement in renal osteodystrophy.

In 25 patients and 11 follow-up studies the clinical usefulness of bone marrow scanning with 111In-chloride in aplastic anaemia is evaluated. Semi-quantitative scanning of bone marrow scan results and the presence of bone marrow extension have proven to be helpful in monitoring the disease and determining aetiological factors. This study shows that 111In-chloride is able to demonstrate regional difference in the bone marrow status of the patient suffering from aplastic anaemia, thereby offering a useful alternative for iron radionuclides.

The accuracy of scintigraphy in focal liver disease was evaluated by comparing the scintigraphic and autopsy findings in 59 patients. The interval between scintigraphy and autopsy was not more than a few weeks. The overall agreement rate was 49 in 59 (83%), with four out of 26 (15%) false positive and six out of 33 (18%) false negative reports. Defects smaller than 2 1/2 cm were the principal source of false negative reports. The accuracy of interpretation in cases with liver weights up to 2000 g was significantly (P less than 0.025) lower than for higher weights. Detection of a single focal lesion by scintigraphy was found to be unreliable (only two out of 13 correct). Estimation of spleen weights by scintigraphy was disappointing. Liver weight estimates were somewhat more satisfactory.

5 consecutive patients with osteoid osteoma were examined with bone scintigraphy and 67Ga scintigraphy. In 2 cases a 'three-phase' bone scintigraphy was performed. Scintigraphic features included obvious 67Ga uptake and diffusely increased accumulation on blood pool images. Thus, osteoid osteoma may possess the same scintigraphic characteristics as osteomyelitis.

To study the role of the spleen in the elimination of immune complexes we examined mononuclear phagocyte system function in eight healthy controls and eight splenectomized patients, with soluble 123I-labelled aggregates of human immunoglobulin G (AIgG). No differences were found between the two groups in elimination and degradation of AIgG. The loss of splenic function was compensated for by increased uptake of AIgG by the liver. With the dose of 123I-AIgG used in this study (10 micrograms/kg body weight), significant generation of C3a was observed. No correlation was found between erythrocyte CR1 number and the fraction of aggregates that bound to erythrocytes.