Photopenic Lesions in Bone Marrow Scintigraphy Using Technetium-99m Labeled Antigranulocyte Antibody without Known Tumour

Aim: The purpose of this study was to elucidate the frequency of photopenic lesions in patients without known tumour disease by using bone marrow scintigraphy with Tc-99m labeled anti-NCA-95. Methods: Whole body immunoscintigraphy (IS) was performed in 141 consecutive patients with fever of unknown origin. The age ranged between 20 and 88 years with a mean age of 57 years. None of the patients had known tumour disease. Scans were evaluated with respect to photopenic lesions and to bone marrow distribution. Results: IS showed bone marrow defects in the axial skeleton in 16 patients (11 %). With the help of the typical scintigraphic defect pattern, the cause of the lesions was clearly identified as degenerative changes in four patients and in one patient as due to prior sternotomy. In the remaining 11 patients the origin of the defects became evident when the case history or additional imaging was consulted. The mean age of these 16 patients was 69 years ranging from 50 to 88 years. There was an age-related frequency of defects. 10% of the patients from 50 to 59 years showed defects, 60-69 years 9%, 70-79 years 30%, and 33% of the patients from 80 to 89 years had defects. IS was not hampered by tracer uptake to liver or spleen in 93 patients. Left caudal ribs were obscured in 48 patients with intense tracer uptake to the spleen. No or markedly reduced tracer uptake was found in caput humeri and caput femori in 94 and 82 patients, respectively. Patchy tracer uptake to the bone marrow of the limbs was seen in 13/62 patients showing marrow expansion in the lower limbs and 14/55 with marrow expansion in the upper limbs. The patchy pattern was asymmetric in 12 of these patients. Conclusion: The results of the present study reveal that using Tc-99m NCA-95, photopenic lesions of the bone marrow are rarely seen in patients without known malignant disease. The occurrence of benign lesions is age-related. The benign cause of the lesion was obvious from location and pattern of the lesion in about 30% of the cases. Evaluation of lesions in the upper and lower limbs may be hindered due to physiological variation of marrow distribution. Nevertheless, IS appears to be well-suited for the detection and localization of bone marrow metastases.

FDG-PET imaging for the staging and follow-up of small cell lung cancer

The staging procedures for small cell lung cancer do not differ appreciably from those for other forms of lung cancer. For practical purposes, the TNM stages are usually collapsed into a simple binary classification: limited disease and extensive disease. This study was performed to answer the question of whether fluorine-18 labelled 2-deoxy-2-D-glucose positron emission tomography (FDG-PET) imaging permits appropriate work-up (including both primary and follow-up staging) of patients presenting with small cell lung cancer, as compared with currently recommended staging procedures. Thirty-six FDG-PET examinations were performed in 30 patients with histologically proven small cell lung cancer. Twenty-four patients were examined for primary staging while four were imaged for therapy follow-up only. Two patients underwent both primary staging and up to four examinations for therapy follow-up. Static PET imaging was performed according to a standard protocol. Image reconstruction was based on an ordered subset expectation maximization algorithm including post-injection segmented attenuation correction. Results of FDG-PET were compared with those of the sum of other staging procedures. Identical results from FDG-PET and the sum of the other staging procedures were obtained in 23 of 36 examinations (6x limited disease, 12x extensive disease, 5x no evidence of disease). In contrast to the results of conventional staging, FDG-PET indicated extensive disease resulting in an up-staging in seven patients. In one patient in whom there was no evidence for tumour on conventional investigations following treatment, FDG-PET was suggestive of residual viability of the primary tumour. Furthermore, discordant results were observed in five patients with respect to lung, bone, liver and adrenal gland findings, although in these cases the results did not affect staging as limited or extensive disease. Moreover, FDG-PET appeared to be more sensitive for the detection of metastatic mediastinal and hilar lymph nodes and bone metastases. Finally, all findings considered suspicious for tumour involvement on the other staging procedures were also detected by FDG-PET. It is concluded that FDG-PET has potential for use as a simplified staging tool for small cell lung cancer.

PET scanning and patient reported dysphagia before and after chemotherapy (CT) for prediction of pathological response after CT and chemoradiotherapy (CRT) in patients with locally advanced esophageal cancer (EC): A multicenter phase ll trial of the Swiss

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Background: Only responding patients (pts) ultimately benefit from preoperative therapy for locally advanced EC. To predict response quality after CRT and detect non-responders earlier, we evaluated changes from baseline in FDG uptake by PET scans and patient reported dysphagia after two cycles of CT. Methods: Pts with resectable, locally advanced squamous cell carcinoma or adenocarcinoma of the esophagus were treated with 2 cycles of CT with docetaxel/cisplatin (DC) q3w followed by CRT (DC weekly x5 with concomitant 45 Gy RT) and surgery. PET imaging using [F]-deoxyglucose (FDG) uptake and subjective dysphagia assessment using a quality of life module specific to EC (EORTC QLQ-OES24) were performed at baseline and after the 2nd cycle of CT. 40% decrease of FDG uptake was prospectively hypothesized to be an early predictor for a pathological complete remission (tumor regression grade 1, TRG) and subtotal regression (TRG 2) after the CRT. The predictive value of improvement in dysphagia was tested by analysis of covariance with baseline dysphagia as covariate. Results: Out of included 66 pts, 56 completed preoperative therapy and surgery. Dysphagia scores (range 0–100) were available in 51 pts, mean changes were 14 (n=13), 12 (n=16) and 12 (n=22) for pts with TRG 1, 2 or >2, respectively, lacking any significance. 44 pts had two PET scans (5: centers not participating, 3: no FDG-uptake at baseline, 4: second scan too late or not done). Mean FDG-decrease was 49% (n=7), 44% (n=17), 15% (n=20) for pts with TRG 1, 2 or >2, respectively. Less than 40% reduction in FDG uptake predicted non-response (TRG>2) with sensitivity 70%, specificity 50%, negative predictive value 70% and positive predictive value 50%. FDG- uptake reduction indicated reduced risk of TRG>2 in a logistic regression model (p<0.01, 95%-CI 2–273). Conclusions: Decreased FDG uptake in sequential PET scans strongly correlates with tumor response, but is not accurate enough to early identify non- responders. Early improvement of dysphagia after 2 cycles CT did not predict TRG after CRT.

No significant financial relationships to disclose.

Regional myocardial perfusion defects during exercise, as assessed by three dimensional integration of morphology and function, in relation to abnormal endothelium dependent vasoreactivity of the coronary microcirculation

OBJECTIVE

To test the hypothesis that scintigraphic regional myocardial perfusion defects during exercise in patients with normal coronary angiography may be related to abnormal endothelium dependent vasoreactivity of the corresponding myocardial territory in response to cold pressor testing.

METHODS

38 patients were classified into two groups according to the presence or absence of exercise induced scintigraphic myocardial perfusion defects. A cold pressor test was done in all patients during routine coronary angiography, followed by dynamic positron emission tomography to establish coronary blood flow mediated vasoreactivity of the epicardial coronary artery and the myocardial territories supplied by the left anterior descending, left circumflex, and right coronary arteries.

RESULTS

28 patients had regional myocardial perfusion defects while 10 had normal scintigraphic imaging. The three dimensional scintigraphic fusion image revealed 49 regional myocardial perfusion defects with a mean (SD) reversibility of the original stress defect of 20 (3)%. In patients with exercise induced regional myocardial perfusion defects, the responses of epicardial luminal area and regional myocardial blood flow (RMBF) to cold pressor testing were reduced compared with patients with normal perfusion imaging (epicardial luminal area: 5.2 (1.2) to 4.2 (0.86) mm2 v 4.7 (0.5) to 5.8 (0.5) mm2; RMBF: 0.75 (0.16) to 0.78 (0.20) ml/g/min v 0.75 (0.15) to 1.38 (0.26) ml/g/min; p < or = 0.03, respectively). In patients with regional abnormal scintigraphic perfusion, the corresponding RMBF response to cold pressor testing was more severely impaired than the mean myocardial blood flow in the remaining two vascular territories, but the difference was not significant (0.75 (0.16) to 0.78 (0.20) ml/g/min v 0.75 (0.10) to 0.87 (0.12) ml/g/min; NS). The endothelium independent increase in RMBF induced by glyceryl trinitrate did not differ between patients with exercise induced myocardial perfusion defects and those with normal perfusion images (0.75 (0.16) to 0.94 (0.09) ml/g/min v 0.75 (0.15) to 0.94 (0.09) ml/g/min; NS). There was a highly significant correlation between the endothelium dependent responses of RMBF to cold pressor testing and the severity of exercise induced scintigraphic regional myocardial perfusion defects (r = 0.95, p = 0.001).

CONCLUSIONS

Exercise induced scintigraphic regional myocardial perfusion defects in patients with angina but normal coronary angiography may be related to abnormal endothelium dependent vasoreactivity of the corresponding myocardial territory.

Validation of FDG positron emission tomography for differentiation of unknown pulmonary lesions

OBJECTIVE

The impact of the (2-(fluorine-18)-fluoro-2-2deoxy-D-glucose)-positron emission tomography ((18)F-FDG-PET) for discrimination of pulmonary lesions was evaluated in a single centre prospective study.

METHODS

In the study, 109 patients with pulmonary lesions of unknown origin verified by computed tomography were enrolled consecutively (April 1999--May 2000). They were subject to (18)F-FDG-PET diagnostics. (18)F-FDG-PET images were interpreted by two independent nuclear medicine physicians who were blinded to the results of other imaging procedures. In 87 patients, surgery was applied followed by histological investigation, which served as the gold standard. In 22 other patients, extensive tumour load or assumed benign dignity of the lesions prevented surgery.

RESULTS

Overall sensitivity of (18)F-FDG-PET in 87 resected patients was 0.86. Differentiation in malignant (n = 69) and benign lesions (n = 18) revealed sensitivities of 0.9 and 0.72, respectively. Sensitivity of (18)F-FDG-PET in inflammatory lesions was markedly lower (0.43) than in benign tumours (0.91). Standard uptake values were significantly increased in malignant tumours compared with benign lesions (9.9 and 1.6, respectively; P = 0.035). There was a clear correlation of sensitivity with tumour size with a failure rate of 27% in lesions < or = 1cm (n = 15), 10% (n = 20) in lesions between 1 and 2 cm and 12% (n = 45) above 2 cm. In primary bronchial carcinoma, a clear correlation of sensitivity was observed with regard to tumour grading (G1, three out of five; G2, 24 out of 27; G3, 26 out of 26; and G4, one out of one). Lymph node involvement was correctly suggested in 10 out of 19 (52.6%) patients. However, false positive lymph node enhancement was indicated in one out of 18 (5.5%) operated patients with benign lesions and eight out of 39 (20.5%) with bronchial carcinoma.

CONCLUSION

(18)F-FDG-PET at present does not serve as the gold standard for early detection of small and well-differentiated tumours. However, it contributes efficiently to the detection of malignancy in tumours >1cm, which are moderately or poorly differentiated. Positive lymph node imaging must not preclude surgery but requires histological proof. Discrimination of benign and malignant pulmonary tumours by (18)F-FDG-PET appears to be hampered in inflammatory lesions.

Whole-body 18F dopa PET for detection of gastrointestinal carcinoid tumors

PURPOSE

To evaluate fluorine 18 (18F) dopa positron emission tomography (PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors.

MATERIALS AND METHODS

After evaluation of the normal distribution of 18F dopa, 17 patients with histologically confirmed tumors were examined with 18F dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomography and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclear medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard.

RESULTS

Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph node metastases, and 37 organ metastases. 18F dopa PET led to 60 true-positive findings (seven primary tumors, 41 lymph node metastases, 12 organ metastases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 organ metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 67 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities: 18F dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 of 92); morphologic procedures, 73% (67 of 92). Although the morphologic procedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging.

CONCLUSION

18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.

Effect of ascorbic acid on endothelial dysfunction of epicardial coronary arteries in chronic smokers assessed by cold pressor testing

BACKGROUND

In chronic smokers there is evidence for increased formation of oxygen-derived free radicals within the vessel wall impairing endothelial function. It has been suggested that the inactivation of endothelium-derived nitric oxide by oxygen free radicals contributes to endothelial dysfunction. Hence, we tested the hypothesis that in chronic smokers the antioxidant ascorbic acid could improve abnormal endothelial function of epicardial coronary arteries.

METHODS AND RESULTS

Thirty-one patients (mean age 57 +/- 9 years) referred for routine diagnostic catheterization for evaluation of chest pain and without angiographically significant coronary artery stenoses were randomly assigned to one of the study groups to assess vasomotor response of epicardial coronary arteries due to cold pressor testing (CPT) before and after intravenous infusion of 3 g of ascorbic acid or 100 ml x 0.9% saline infusion. In 6 controls (mean age 55 +/- 3 years) CPT led to a similar increase in luminal area before and after ascorbic acid administration (26.5 +/- 15.0 vs. 28.4 +/- 17.7%, p = NS). In 15 chronic smokers (mean age 55 +/- 9 years), CPT induced a decrease in the luminal area of -18.5 +/- 6.3%. This flow-dependent vasoconstriction was significantly reversed to 7.7 +/- 6.2% (p < or = 0.03) vasodilation after intravenous ascorbic acid administration. In 10 chronic smokers (mean age 57 +/- 11 years) saline infusion (placebo) did not have a significant effect on CPT-induced vasoconstriction (-12.7 +/- 5.1 vs. -13.1 +/- 5.1%, p = NS). The CPT-induced increase in luminal area in chronic smokers after ascorbic acid infusion was significant compared to controls and placebo (each p < or = 0.05). Our assessment of endothelium-independent responses to nitroglycerin revealed no significant differences between the single study groups (p = NS).

CONCLUSION

In chronic smokers acute intravenous administration of ascorbic acid significantly improves CPT-induced coronary endothelium-dependent dysfunction. According to the current understanding, this effect is due to improved cellular redox imbalance and prevention of nitric oxide inactivation in the endothelium and subendothelial space.

18F-DOPA positron emission tomography for tumour detection in patients with medullary thyroid carcinoma and elevated calcitonin levels

In spite of the availability of numerous procedures, diagnostic imaging of tumour manifestations in patients with medullary thyroid carcinoma and elevated calcitonin levels is often difficult. In the present study, the new procedure of fluorine-18 dihydroxyphenylalanine positron emission tomography (18F-DOPA PET) was compared with the established functional and morphological imaging methods. After evaluation of the normal distribution of 18F-DOPA, 11 patients with medullary thyroid carcinoma were examined using 18F-DOPA PET. Results of 18F-fluorodeoxyglucose (18F-FDG) PET, somatostatin receptor scintigraphy (SRS) and morphological tomographic imaging (CT/MRI) were available for all patients. All individual procedures were evaluated without reference to prior information. Data assessment for each patient was based on cooperation between experienced radiologists and specialists in nuclear medicine, who considered all the available findings (histological results, imaging, follow-up studies). This cooperation served as the gold standard against which the results of the individual procedures were evaluated. A total of 27 tumours were studied [three primary tumours (PT)/local recurrence (LR), 16 lymph node metastases (LNM) and eight organ metastases (OM)]. 18F-DOPA PET produced 17 true-positive findings (2 PT/LR, 14 LNM, 1 OM), 18F-FDG PET 12 (2 PT/LR, 7 LNM, 3 OM), SRS 14 (2 PT/LR, 8 LNM, 4 OM) and morphological imaging 22 (3 PT/LR, 11 LNM, 8 OM). The following sensitivities were calculated with respect to total tumour manifestations: 18F-DOPA PET 63%, 18F-FDG PET 44%, SRS 52%, morphological imaging 81%. Thus, the morphological imaging procedures produce the best overall sensitivity, but the specificity for PT/LR (55%) and LNM (57%) was low. With respect to lymph node staging, the best results were obtained with 18F-DOPA PET. 18F-DOPA PET is a new functional imaging procedure for medullary thyroid carcinoma that seems to provide better results than SRS and 18F-FDG PET. Moreover, the data indicate that no single procedure provides adequate diagnostic certainty. Therefore, 18F-DOPA PET is a useful supplement to morphological diagnostic imaging, improving lymph node staging and enabling a more specific diagnosis of primary tumour and local recurrence.

[New developments in diagnosis of coronary heart disease--3D fusion image]

The interpretation of three-dimensional (3D) structures of the coronary tree and the myocardium by a clinician demands a subjective visual integration of two-dimensional (2D) images of cardiac diagnostic procedures like coronary angiography and myocardial scintigraphy. Although in the conventional analysis of 2D display scintigraphic myocardial perfusion segments are arbitrarily assigned to three major coronary artery systems, the standard myocardial perfusion distribution territories correspond with the individual pathologic-anatomic coronary tree in only 50-60% of the patients. Hence, the mental integration of both 2D images of coronary angiography and myocardial scintigraphy does not necessarily allow an accurate assignment of particular myocardial perfusion regions to the corresponding vessels. For an objective assignment of each vessel segment of the coronary tree to the corresponding myocardial regions, we have developed a 3D "fusion image" technique and applied it to patients with coronary artery disease. Cause-and-effect relationships may be more obvious with 3D data fusion and may enable an easier comparison of anatomy and physiology. Preliminary results demonstrate that our newly developed 3D fusion image is useful for accurate assignment of coronary vessel segments to the corresponding myocardial perfusion regions and suggest that it may allow the clinician a comprehensive and accurate assessment of the patient's myocardial status.

Evaluation of transmyocardial laser revascularization by following objective parameters of perfusion and ventricular function

BACKGROUND

Does transmyocardial laser revascularization (TMLR), a new surgical technique for treating patients with otherwise intractable angina pectoris, improve myocardial perfusion, metabolism, and, consequently, function?

METHODS

Patients referred for TMLR, alone or with coronary artery bypass grafting (CABG), were preoperatively evaluated clinically and by treadmill stress testing, echocardiography, ventriculography, radionuclide assessment of perfusion and metabolism, and hemodynamic assessment. Intraoperatively it was decided that some patients only required CABG. Follow-up evaluations were repeated after 6 (n = 40) and 12 months (n = 23) and compared with preoperative values.

RESULTS

CABG only was performed in 35 cases, TMLR + CABG in 17, TMLR only in 45. 1-year mortality was 11% in the TMLR, zero in the TMLR + CABG, and 11% in the CABG groups. In all groups a significantly improved CCS angina- and NYHA class was observed immediately after operation and after 6 and 12 months. In all study groups treadmill tolerance (p<0.05) improved, but regional and global function, perfusion at rest, and metabolism were not significantly changed at 6 and 12-months follow-ups. Perfusion studies under stress demonstrated an improvement only in the CABG group after 12 months (p<0.05), whereas in both TMLR groups the lasered ischemic segments remained unchanged.

CONCLUSIONS

TMLR significantly improves long-term clinical status and treadmill stress tolerance, but appears to have little if any effect upon regional and global function, perfusion, and metabolism.

3D assessment of myocardial perfusion parameter combined with 3D reconstructed coronary artery tree from digital coronary angiograms

In patients with coronary artery disease coronary angiography plays an important role in the clinical decision-making process. However, it has been recognized that no simple relation exists between the visually or quantitatively evaluated severity of coronary artery stenoses and its effects on regional myocardial perfusion. This paper describes for the first time the development and application of a 3D technique that visualizes and quantifies regional myocardial perfusion parameters from biplane coronary angiograms by using the impulse response analysis technique. The 3D reconstructed coronary tree is automatically superimposed on the 3D perfusion image to generate and visualize an 'integrated' 3D image. The preliminary results in patients with critical coronary artery stenoses indicate that our combined 3D fusion image provides flow information from the major coronary arteries. This 3D fusion image may provide useful information in the management of patients with coronary artery disease.

Fusion imaging: combined visualization of 3D reconstructed coronary artery tree and 3D myocardial scintigraphic image in coronary artery disease

BACKGROUND

In patients with coronary artery disease, coronary angiography is performed for assessment of epicardial coronary artery stenoses. In addition, myocardial scintigraphy is commonly used to evaluate regional myocardial perfusion. These two-dimensional (2D) imaging modalities are typically reviewed through a subjective, visual observation by a physician. Even though on the analysis of 2D display scintigraphic myocardial perfusion segments are arbitrarily assigned to three major coronary artery systems, the standard myocardial distribution territories of the coronary tree correspond only in 50-60% of patients. On the other hand, the mental integration of both 2D images of coronary angiography and myocardial scintigraphy does not allow an accurate assignment of particular myocardial perfusion regions to the corresponding vessels. To achieve an objective assignment of each vessel segment of the coronary artery tree to the corresponding myocardial regions, we have developed a 3D 'fusion image' technique and applied it to patients with coronary artery disease. The morphological data (coronary angiography) and perfusion data (myocardial scintigraphy) are displayed in a 3D format, and these two 3D data sets are merged into one 3D image.

RESULTS

Seventy-eight patients with coronary artery disease were studied with this new 3D fusion technique. Of 162 significant coronary lesions, 120 (74%) showed good coincidence with regional myocardial perfusion abnormality on 3D fusion image. No regional myocardial perfusion abnormality was found in 44 (26%) lesions. Furthermore, the 3D fusion image revealed 24 ischemic myocardial regions that could not be related to angiographically significant coronary artery lesions.

CONCLUSION

The results of this study demonstrate that our newly developed 3D fusion technique is useful for an accurate assignment of coronary vessel segments to the corresponding myocardial perfusion regions, and suggest that it may be helpful to improve the interpretative and decision-making process in the treatment of patients with coronary artery disease.

Transmyocardial laser revascularization: experimental studies in healthy porcine myocardium

BACKGROUND

Clinical studies have demonstrated a significant reduction of cardiac index shortly after transmyocardial laser revascularization in patients with low ejection fraction. We analyzed the influence of transmyocardial laser revascularization on healthy myocardium in pigs.

METHODS

Carbon dioxide channels were created in 20 pigs which were observed for 6 hours. Ten pigs received one laser channel and ten pigs two laser channels per cm2 in the left anterior descending artery region. Seven pigs served as controls. Perfusion (microspheres), function, histochemical, and histologic assessments were subsequently performed.

RESULTS

A significant deterioration of left ventricular stroke work index was observed shortly after transmyocardial laser revascularization in both laser groups (p < 0.05). After 6 hours the left ventricular stroke work index did not increase and showed significantly reduced values at rest (p < 0.05) and during stress in the laser groups (p < 0.01). Normal regional perfusion, small ischemic and necrotic areas, open laser channels in the left anterior descending artery region and significantly increased myocardial water content were observed in the laser groups (p < 0.01).

CONCLUSIONS

Carbon dioxide laser channels significantly decrease global heart function shortly after transmyocardial laser revascularization in healthy porcine myocardium. This myocardial tissue showed no recovery 6 hours postoperatively.

Photopenic lesions in bone marrow scintigraphy using technetium-99m labeled antigranulocyte antibody without known tumour

AIM

The purpose of this study was to elucidate the frequency of photopenic lesions in patients without known tumour disease by using bone marrow scintigraphy with Tc-99m labeled anti-NCA-95.

METHODS

Whole body immunoscintigraphy (IS) was performed in 141 consecutive patients with fever of unknown origin. The age ranged between 20 and 88 years with a mean age of 57 years. None of the patients had known tumour disease. Scans were evaluated with respect to photopenic lesions and to bone marrow distribution.

RESULTS

IS showed bone marrow defects in the axial skeleton in 16 patients (11%). With the help of the typical scintigraphic defect pattern, the cause of the lesions was clearly identified as degenerative changes in four patients and in one patient as due to prior sternotomy. In the remaining 11 patients the origin of the defects became evident when the case history or additional imaging was consulted. The mean age of these 16 patients was 69 years ranging from 50 to 88 years. There was an age-related frequency of defects. 10% of the patients from 50 to 59 years showed defects, 60-69 years 9%, 70-79 years 30%, and 33% of the patients from 80 to 89 years had defects. IS was not hampered by tracer uptake to liver or spleen in 93 patients. Left caudal ribs were obscured in 48 patients with intense tracer uptake to the spleen. No or markedly reduced tracer uptake was found in caput humeri and caput femori in 94 and 82 patients, respectively. Patchy tracer uptake to the bone marrow of the limbs was seen in 13/62 patients showing marrow expansion in the lower limbs and 14/55 with marrow expansion in the upper limbs. The patchy pattern was asymmetric in 12 of these patients.

CONCLUSION

The results of the present study reveal that using Tc-99m NCA-95, photopenic lesions of the bone marrow are rarely seen in patients without known malignant disease. The occurrence of benign lesions is age-related. The benign cause of the lesion was obvious from location and pattern of the lesion in about 30% of the cases. Evaluation of lesions in the upper and lower limbs may be hindered due to physiological variation of marrow distribution. Nevertheless, IS appears to be well-suited for the detection and localization of bone marrow metastases.

Evaluation of positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose for the differentiation of chronic pancreatitis and pancreatic cancer

BACKGROUND

The clinical presentation of patients with pancreatic cancer may resemble the clinical picture of chronic pancreatitis. A definitive preoperative diagnosis is not always obtained in patients with a history of chronic pancreatitis despite the use of modern imaging techniques. Operative strategy therefore remains unclear before operation in these patients.

METHODS

Positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) was introduced recently into clinical oncology because of its ability to demonstrate metabolic changes associated with various disease processes. The impact of FDG-PET on the differentiation of chronic pancreatitis and pancreatic cancer was investigated. FDG-PET was performed in 48 patients with chronic pancreatitis (n = 12), acute pancreatitis (n = 3) and pancreatic cancer (n = 27), and in controls (n = 6). Histological examination was undertaken in all cases except controls. The FDG-PET results were obtained without knowledge of results of other imaging procedures. The results were then compared with those of computed tomography, ultrasonography, endoscopic retrograde cholangiopancreaticography, operative findings and histology. PET images were analysed semiquantitatively by calculating a standard uptake value (SUV) 90-120 min after application of the tracer.

RESULTS

Cut-off values were validated as follows: SUV greater than 4.0 for pancreatic cancer, SUV of 3.0-4.0 for chronic pancreatitis, and SUV of less than 3.0 for controls. Sensitivity and specificity of PET imaging were 0.96 and 1.0 for pancreatic cancer, and 1.0 and 0.97 for chronic pancreatitis. In five cases only FDG-PET led to the correct preoperative diagnosis.

CONCLUSION

The results give further evidence that FDG-PET is an important non-invasive method for the differentiation of chronic pancreatitis and pancreatic cancer. Delayed image acquisition in the glycolysis plateau phase permits improved diagnostic performance. This imaging technique is extremely helpful before operation in patients with an otherwise unclear pancreatic mass, despite its costs.

[Treatment strategies in therapy refractory angina pectoris: transmyocardial laser revascularization]

BACKGROUND

Does transmyocardial laser revascularization (TMLR) as a new surgical technique for treating patients with otherwise intractable angina pectoris improve myocardial perfusion or contractility?

METHODS

Sixty-seven patients transferred for TMLR were evaluated by clinical evaluation, treadmill stress testing, echocardiography, ventriculography, and hybrid positron emission tomography preoperatively and in patients treated with TMLR at 6 and 12 month follow up. Hemodynamic assessment and clinical evaluation were performed perioperatively.

RESULTS

In 28/67 cases (42%) CABG, in 9/67 patients (13%) CABG in combination with TMLR (combined group), and in 30/67 patients (45%) only TMLR (sole group) were performed. Perioperative mortality in the sole group was 13%, in the combined group zero, and in the CABG group 11%. In all groups a significantly improved clinical status (p < or = 0.01) 1 week postoperatively and in TMLR groups also at 6 and 12 months was observed. In the TMLR groups treadmill tolerance (p < 0.05) improved, although function, perfusion, and metabolism did not change significantly at the 6 and 12 month follow up.

CONCLUSION

TMLR significantly improves clinical status and treadmill stress tolerance, but does not change function, perfusion, and metabolism.

Early-onset Alzheimer's disease due to mutations of the presenilin-1 gene on chromosome 14: a 7-year follow-up of a patient with a mutation at codon 139

Mutations in the presenilin-1 gene (PS-1 gene) on chromosome 14 have recently been identified as a cause of familial early-onset Alzheimer's disease (EOAD). To our knowledge, only two German EOAD patients with mutations in the PS-1 gene have been identified thus far. Herein we report the case of a German EOAD patient with a family history of dementia and a missense mutation at codon 139 (M139V) of the PS-1 gene. The patient came to our clinic for the first time when he was 44 years old. During the following 7 years, his Mini-Mental State Examination (MMSE) score dropped from 24 to 0. Myocloni were an early neurological symptom that was already present during the first consultation. We could demonstrate that myoclonic activity was of cortical origin using a back-averaging method. Magnetic resonance imaging (MRI) revealed only slight changes in the early stage of the disease. Follow-up MRI studies showed progression of bitemporal ventricular enlargement and progressive frontal and temporal cortical atrophy. Although the majority of EOAD patients belong to the sporadic (non-genetic) type of AD, early-onset dementia, early myocloni and a familial history of AD should direct attention to the possibility of a genetic form of AD.

Transmyocardial laser-revascularization: experimental studies on prolonged acute regional ischemia

OBJECTIVE

This experimental study in pigs was undertaken to answer the question whether TMLR after acute myocardial infarction may improve regional myocardial perfusion, left ventricular function and diminish myocardial necrosis in the area at risk.

METHODS

Thirty open-chest anesthetized pigs were observed for 6 h, six pigs served as controls. In 24 pigs, occlusion of the left anterior descending artery (LAD) beyond the first diagonal branch was performed: seven pigs had LAD occlusion only (ischemia group), and 17 pigs were treated by TMLR (using a CO2-laser, energy: 40 J) prior to coronary occlusion; nine pigs received one laser channel (1 mm diameter) per cm2 (laser group 1) and eight pigs two channels per cm2 in the LAD territory (laser group 2). Regional myocardial blood flow by microspheres, function (franc starling curves), histochemical assessment (triphenyl tetrazolium chloride, TTC and histology), were performed.

RESULTS

The lased pigs were less prone to ventricular fibrillation (laser group 2, 38%; laser group 1, 56%; ischemic group, 100%; P < 0.05), and showed a significant smaller area of necrosis (TTC) in the area at risk (laser group 1, 23%; laser group 2, 14%; vs. ischemia group, 31%; P < 0.01). There was no significant difference between laser-treated and ischemia hearts regarding the amount of blood flow into the infarcted LAD region and the maximal left ventricular stroke work index after 6 h (P = n.s). Regional myocardial blood flow: ischemia group, 4 +/- 5 ml/100 g/min; laser group 1, 3 +/- 10 ml/100 g/min, and laser group 2, 2 +/- 10 ml/100 g/min; maximal left ventricular stroke work index: ischemia group, 1.8 mJ/g; laser group 1, 2.1 mJ/g and laser group 2, 2.1 mJ/g.

CONCLUSIONS

This model of acute regional ischemia demonstrates that CO2-laser revascularization diminish significantly the incidence of ventricular fibrillation and necrosis in the area at risk, and does not change regional myocardial perfusion and global left ventricular function. This experiment indicates that TMLR may be an alternative in treating advanced ischemic heart disease.

Transmyocardial laser revascularization (TMLR) in patients with unstable angina and low ejection fraction

OBJECTIVE

Does perioperative use of the intraaortic balloon pump (IABP) improve the postsurgical outcome of patients presenting with endstage coronary artery disease, unstable angina and low ejection fraction transferred for transmyocardial laser revascularization (TMLR)?

METHODS

TMLR, as sole therapy combined with the perioperative use of an intraaortic balloon pump has been assessed in seven patients with endstage coronary artery disease, unstable angina and low ejection fraction (EF < 35%). Six out of seven patients had signs of congestive heart failure. These patients are compared with 23 patients with endstage coronary artery disease, stable angina and EF > 35%, who were treated with TMLR as sole therapy without the use of IABP. The creation of transmural channels was performed by a CO2-laser. All patients were evaluated by hybrid positron emission tomography (perfusion SPECT and viability PET) and ventriculography preoperatively. Echocardiography, clinical status and hemodynamic assessment by Swan Ganz catheter were performed perioperatively.

RESULTS

The perioperative mortality of this combined procedure (TMLR and IABP) was zero. Three out of seven patients had pneumonia with complete recovery. Swan Ganz catheter examinations showed deterioration of LV-function after TMLR intraoperatively and improvement after 2 h and further after 6 h on ICU (P < 0.05). In contrast, a decrease of LV-function in sole TMLR patients with an EF > 35%) has not been observed. Patients with EF < 35% needed the IABP for 2.3 days and moderate dose catecholamines for a mean of 3.0 days. The postoperative EF and resting wall motion score index (WMSI) of all analysed LV segments (evaluated by echocardiography) did not change compared to baseline (EF 31.3+/-2.6 preop. to 32.8+/-3.2 postop.; WMSI: 1.75+/-0.14 at baseline to 1.71+/-0.17 postop.). The average Canadian Angina Class at the time of discharge decreased from 4.0+/-0 (baseline) to 2.3+/-0.5 (P < 0.05) and the NYHA-Index from 3.9+/-0.3 to 2.7+/-0.5. No patient had signs of angina pectoris, whereas two patients still had signs of congestive heart failure.

CONCLUSIONS

The reported data support our concept to start IABP preoperatively in patients with reduced LV contractile reserve in order to provide cardiac support during the postoperative phase of reversible decline of LV-function induced by TMLR.

[Indications for nuclear medicine diagnosis in trauma surgery]

Skeletal scintigraphy is the most frequently utilized nuclear medicine imaging procedure in traumatology. Concerning any skeletal abnormality associated with changes in local perfusion, exudation and metabolism, it is a sensitive functional imaging procedure to detect bony disease. However, because of the varying causes of bony disease, it is characterized by a low specificity. Further, specificity may be enhanced, when patient history, clinical and lab results as well as results obtained from other diagnostic imaging procedures are combined with the result of skeletal scintigraphy. On the other hand, it is known that metabolic abnormalities of the skeleton depicted by radionuclide imaging occur much earlier than structural changes visible on X-ray imaging. Beside skeletal scintigraphy, antigranulocyte antibody or labelled leucocyte imaging may greatly assist in the detection of inflammation or infection following joint replacement surgery, respectively. Ultimatively, a combination of clinical, lab and imaging results including radionuclide imaging may represent the best approach to answer some questions asked by surgical traumatologists.

[Double isotope albumin flux measurement: diagnosis and therapeutic monitoring of acute lung injury]

PURPOSE

Acute Lung Injury (ALI) is a clinical condition which is associated with a high lethality. It is characterized by an increased pulmonary capillary permeability and non-cardiogenic pulmonary edema. This study was designed to answer the question whether double isotope albumin-flux measurement is a useful tool both for diagnosis of increased pulmonary capillary permeability and for monitoring therapeutic interventions (nitric oxide (NO) inhalation).

METHOD

In 12 patients with clinical signs of ALI, transvascular albumin-flux was measured by a double radioisotope technique before, during and after NO inhalation. 99mTc labeled albumin and 51Cr labeled autologous erythrocytes were used as tracer. The radioactivity of both radiopharmaceuticals was measured externally over the right lung by a radiation probe and simultaneously in arterial blood. For quantification of transvascular albumin-flux Normalized Index (NI) and Normalized Slope Index (NSI) were calculated. Furthermore, pulmonal vascular pressures and other physiological parameters were recorded.

RESULTS

All 12 patients showed markedly increased NSI before inhalation of NO. NSI decreased from 0.0074 +/- 0.0046 min-1 without nitric oxide to -0.0051 +/- 0.0041 min-1 during nitric oxide and increased to 0.0046 +/- 0.0111 min-1 after nitric oxide. The decrease of the NSI correlated well with decrease of venous pulmonary resistance during inhalation of NO.

CONCLUSION

Inhalation of NO reduces transvascular albumin-flux in patients with ALI. Double isotope albumin-flux measurement enables diagnosis of increased capillary permeability as well as monitoring therapeutic interventions.

Doppelisotopen-Albuminfluxmessung: Diagnose und Therapiemonitoring des Acute Lung Injury

Ziel: Acute Lung Injury (ALI) ist ein Krankheitsbild mit hoher Letalität, das durch eine erhöhte pulmonale Kapillarpermeabilität mit einem nichtkardialen Lungenödem gekennzeichnet ist. In der vorliegenden Studie sollte überprüft werden, ob die Doppelisotopen-Albuminfluxmessung sich neben der Diagnostik einer erhöhten pulmonalen Kapillarpermeabilität auch zum Monitoring therapeutischer Interventionen (Stickstoffmonoxid (NO)-lnhalation) eignet. Methoden: Bei 12 Patienten mit ALI wurde der transvaskuläre Albuminflux vor, während und nach NO-Inhalation mittels Doppelisotopenmethode bestimmt. Als Tracer dienten 99mTc markiertes Albumin und 51Cr markierte autologe Erythrozyten. Die Aktivität beider Radiopharmazeutika wurde simultan über der Lunge mit einem Sondenmeßgerät und im arteriellen Blut ermittelt. Zur Quantifizierung des transvaskulären Albuminfluxes wurden der Normalized Index (Nl) und Normalized Slope Index (NSI) errechnet. Darüber hinaus wurden die pulmonalen Gefäßdrücke und weitere physiologische Parameter bestimmt. Ergebnisse: Alle 12 Patienten wiesen, als Ausdruck einer schweren Permeabilitätsstörung vor der NO-Inhalation deutlich erhöhte NSI auf. Während der NO-Inhalation fiel der NSI von durchschnittlich 0,0074 ± 0,0046 min-1 auf -0,0051 ± 0,0041 min-1. Nach Beendigung der NO Gabe stieg der NSI erneut auf durchschnittlich 0,0046 ± 0,0111 min-1 an. Der NSI Abfall zeigte eine gute Korrelation zum NO-induzierten Abfall des pulmonal-venösen Gefäßwiderstandes. Schlußfolgerung: Unter NO Inhalation kommt es zu einer Reduzierung des transvaskulären Albuminfluxes. Die Doppelisotopen-Albuminflux-messung eignet sich sowohl zur Diagnostik als auch zum Therapiemonitoring bei ALI-Patienten.

Effect of short-term cardiovascular conditioning and low-fat diet on myocardial blood flow and flow reserve

BACKGROUND

Cardiovascular conditioning reduces resting myocardial oxygen demand by lowering systolic blood pressure and heart rate. Lower myocardial oxygen demand at rest would be expected to be associated with a decrease in resting myocardial blood flow and, consequently, an increase in myocardial flow reserve as the ratio of hyperemic to resting blood flow. However, the effect of controlled exercise together with a low-lipid diet on myocardial blood flow and flow reserve has not been examined in humans.

METHODS AND RESULTS

Myocardial blood flow at rest and after dipyridamole-induced hyperemia (0.56 mg/kg i.v.) was quantified with [13N]ammonia and positron emission tomography in 13 volunteers before and upon completion of a 6-week program of cardiovascular conditioning and a low-fat diet. Exercise capacity and serum lipid profiles were also assessed at the start and finish of the program. Eight normal volunteers of similar age not participating in the conditioning program served as a control group. Cardiovascular conditioning lowered the resting rate-pressure product (8859 +/- 2128 versus 7450 +/- 1496, P < .001), serum cholesterol (217 +/- 36 versus 181 +/- 26 mg/dL), LDL cholesterol (140 +/- 32 versus 114 +/- 24 mg/dL), and triglycerides (145 +/- 53 versus 116 +/- 33 mg/dL, all P < .05). Exercise tolerance (metabolic equivalent of the task, METs) improved significantly from 10.0 +/- 3.0 to 14.4 +/- 3.6 (P < .01). Resting blood flow decreased (0.78 +/- 0.18 versus 0.69 +/- 0.14 mL.g-1.min-1, P < .05), whereas hyperemic blood flow increased (2.06 +/- 0.35 versus 2.25 +/- 0.40 mL.g-1.min-1, P < .05), resulting in an improved myocardial flow reserve (2.82 +/- 1.07 versus 3.39 +/- 0.91, P < .05). Overall, the myocardial flow reserve was significantly related to exercise performance (METs). In the control group, no changes in resting rate-pressure product, serum cholesterol levels, exercise performance, resting or hyperemic myocardial blood flow, or flow reserve were observed.

CONCLUSIONS

Short-term cardiovascular conditioning together with a low-fat diet results in an improved myocardial flow reserve by lowering resting blood flow and increasing coronary vasodilatory capacity. These changes are associated with an improved exercise capacity and may offer a protective effect in patients with coronary artery disease.

Improved dose concept for radioiodine therapy of multifocal and disseminated functional thyroid autonomy

The present study analyzes the improvement of the outcome of radioidine therapy in non-immunogenic hyperthyroidism by adapting the target dose to the 99mTc-pertechnetate thyroid uptake under suppression (TcTUs) prior to radioiodine therapy. The TcTUs is a substitute for the non-suppressible iodine turnover. The 89 patients presented with a basal thyrotropin level of < 0.1 mU/l, normal values for free triiodothyronine and thyroxine and with multifocal or disseminated thyroid autonomy. These terms describe the scintigraphic distribution pattern of autonomous iodine turnover. Thirty-two patients had a TcTUs between 1.6 and 3.2% (group A) and 57 had a TcTUs > 3.2% (group B). Fifty-five patients (three of group A and 52 of group B) were treated previously for overt hyperthyroidism with antithyroid drugs. Target doses of 150 and 200 Gy were used in both groups and 300 Gy in group B only. Six months after radioiodine therapy, a basal TSH level of > or = 0.5 mU/l as criterion of therapy success was observed in 94% of group A and in 54% of group B. Further differentiation of group B shows an increasing success rate with the target dose used: 45% after 150 Gy, 50% after 200 Gy and 90% after 300 Gy. In patients with a basal TSH level of < 0.5 mU/l after radioiodine therapy, the TcTUs was evaluated again.(ABSTRACT TRUNCATED AT 250 WORDS)

Positron emission tomography: a new method for determination of renal function

Positron emission tomography (PET) is a newly evolving diagnostic modality that has been widely used in many facets of clinical medicine, but whose use in the diagnosis and management of disorders of the kidney has not been previously described. Employing the radiotracer N-13 ammonia, flow-dependent extraction of this compound after intravenous injection was used to measure renal blood flow (RBF) in a swine model (N = 10). A mean baseline value of 3.16 ml./min./gm. kidney was obtained with this method, in close agreement with values previously reported using established invasive techniques. Four conditions known to affect RBF were also studied to determine the ability of PET to detect changes in RBF. Kidneys were subjected to varying durations of warm ischemia, demonstrating a progressive decrease in RBF with increasing ischemic insult, with return to normal significantly impaired in animals exposed to the greatest degree of ischemia (180 minutes versus 150 or 120 minutes ischemia). Cross-transplant between animals produced acute allograft rejection and a corresponding marked decrease in RBF that failed to normalize. After unilateral nephrectomy, RBF increased two-fold in the remaining kidney by 7 days (R = 0.79), as predicted for compensatory renal hypertrophy. Lastly, there was an inverse, linear relationship between toxic cyclosporine level and RBF (R = 0.68), indicative of vascular-mediated cyclosporine nephrotoxicity. Positron emission tomography is safe and efficient, and yields an accurate measurement of RBF in several important physiologic states. The development of PET as a quantitative measure of renal function is promising.

Cancer detection with whole-body PET using 2-[18F]fluoro-2-deoxy-D-glucose

OBJECTIVE

This study was done to determine the feasibility and potential utility of whole-body PET using the glucose analogue 2-[18F]fluoro-2-deoxy-D-glucose (FDG) for the detection of primary malignancies and metastatic lesions.

MATERIALS AND METHODS

This was a prospective, nonrandomized study of whole-body FDG-PET imaging carried out at a large university teaching hospital in Los Angeles, CA, U.S.A. The study group consisted of all patients referred for PET imaging (87) with a suspected diagnosis of primary or recurrent malignancy and who had eventual histological confirmation of their lesions.

RESULTS

In the 87 patients, whole-body PET studies were positive (presence of focal FDG uptake relative to surrounding tissues uptake) in 61 of 70 patients (87%) with subsequent biopsy-confirmed primary or recurrent malignant lesions, including carcinomas of breast, lung, ovary, prostate, colon, urinary bladder, and gallbladder origin, as well as malignant melanoma, carcinoid, osteosarcoma, lymphoma, and spinal cord astrocytoma. The PET images revealed no focal hypermetabolism at the known site of tumor in patients with primary prostate carcinoma (two), microscopic ovarian carcinoma (two), breast carcinoma (one), low-grade carcinoid tumors (two), and one patient with recurrent microscopic osteogenic sarcoma. The PET studies detected the primary lesion in 15 of 17 patients with breast carcinoma and in 6 of 6 patients with primary lung carcinoma. Of the 17 patients with benign biopsies, 13 patients had FDG-PET studies without focal areas of uptake.

CONCLUSION

Because of the high glycolytic rate of malignant tissue, the whole-body FDG-PET technique has promise in the detection of a wide variety of both primary and metastatic malignancies. The presence of FDG uptake in benign inflammatory conditions may limit the specificity of the technique. The sensitivity for the detection of malignant lesions was 87% and the positive predictive value was 94%. The whole-body FDG-PET method is promising both in determining the nature of a localized lesion and in defining the systemic extent of malignant disease.

Quantification of glucose utilization in liver metastases: parametric imaging of FDG uptake with PET

Positron emission tomography (PET) fluorodeoxyglucose (FDG) studies are useful for identifying foci of increased FDG uptake in liver metastases, because of the high glycolytic rate of malignancies, as well as for monitoring changes in tumor glucose metabolism during treatment. We performed 15 kinetic PET FDG studies in four patients with metastatic liver disease. We produced parametric images of glucose metabolism in terms of the rate constant K (ml/min/g) for net phosphorylation of FDG. Tumor K values, estimated with nonlinear regression, correlated well with K values estimated with Patlak graphical analysis (r = 0.96), validating the assumption of low k4* values in liver metastases and supporting the use of pixel by pixel Patlak plot analysis of the data to generate parametric images. In normal liver, high levels of glucose-6-phosphatase produce much higher values of k4* than in liver metastases. Uncorrected Patlak graphical analysis underestimates K in normal liver, but this further increases the contrast between tumor and liver and facilitates both tumor detection and quantification. The technique is computationally feasible and is well suited for serial evaluations of tumor metabolism during treatment.

[RARE-MR urography: a rapid MR tomographic imaging procedure for the diagnosis of urinary tract malformations in childhood]

RARE-MR urography (so called "water-pictures") is a fast MR imaging technique that selectively depicts fluid without contrast application. Acquisition time is 6.4 s per slice with 1 excitation, or 23 s per slice with 2 averages respectively. From Sept. 1989 to April 1990 24 children with anomalies of the urinary tract have been examined each by RARE MR urography and one T1-weighted spin-echo sequence. Independent of excretory function, the technique can show dilated calices and renal pelvis, pelviureteric obstruction, renal duplication, and megaureter. However, it cannot distinguish between vesicoureteric reflux and obstructive megaureter. Our first results suggest that RARE MR urography combined with ultrasound, reflux cystography and isotope nephrography, can replace excretory urography in certain circumstances--or at least postpone it to the preoperative phase.

[Captopril-renal function scintigraphy in the clarification of arterial hypertension]

Renal artery stenosis (RAS) is a rare cause of hypertension. Radiological tests can disclose the morphological changes, but not their functional effect on renal function and perfusion. Normalization of the blood pressure can be achieved by intervention (operation, percutaneous transluminal renal angiography; PTRA), in cases of prolonged RAS-induced hypertension long-term preservation of the organ function is most important. The purpose of this study was the validation of captopril renography as a screening test for hypertension secondary to RAS prior to PTRA. Captopril renography with 99mTc-MAG 3 has a high sensitivity (94%) and acceptable specificity (88%) for the screening of hypertensive patients. The positive predictive value is 74% and the negative predictive value 98%, compared with the "gold standard" of angiography.

RARE-MR-urography in the diagnosis of upper urinary tract abnormalities in children

RARE-MR-urography (Rapid Acquisition with Relaxation Enhancement) is a fast MR imaging technique (6.4 s/acquisition) that selectively depicts fluid by heavy T2-weighting. From 9/1989 to 11/1990, RARE-MR urograms were prospectively evaluated in the diagnosis of upper urinary tract abnormalities in 55 children. The method is performed in several planes and combined with a coronal, T1-weighted spin-echo sequence. Forty out of 42 kidneys with dilated renal pelvis, and 21 out of 24 dilated ureters were identified, only the mildly dilated ones were missed. Even in non-functioning kidneys the urinary tract was clearly depicted by RARE-MR-urography. However, no differentiation could be made with this technique between vesicoureteral reflux and non-refluxing dilatation of ureter and/or renal pelvis. All 19 pelviureteric obstructions and all eight renal duplications with a dilated segment were identified. RARE-MR-urography is a new tool for diagnosing urinary tract abnormalities in children without having to employ ionizing radiation, contrast media, or general anesthesia. A dilated urinary tract can be shown in one image displaying the entire urinary system, similar to excretory urography. The technique is presently not able to provide the information of voiding cystourethrography or renal scintigraphy, nor is it as easy to perform as ultrasound. However, in certain cases it may replace excretory urography.