[Nuclear medicine imaging for diagnosis of CRPS I]. / Nuklearmedizinische Diagnostik beim CRPS I.

A three-phase bone scan, before conventional radiography shows morphological changes in CRPS 1, represents a valuable diagnostic tool thanks to the depiction of pathognomonic findings and the localisation ability in all 3 phases. It must be interpreted within the clinical context. In late or subsequent stages the lack of scintigraphic uptake seems to represent the end of the active disease process. The role of three-phase bone scintigraphy in CRPS I is to support or even confirm the diagnosis, given its various presentations. Furthermore, it enables exclusion of other diagnoses such as arthritis, benign or malignant bony lesions, or even metabolic bone diseases such as Paget's disease, particularly if an integrated SPECT/CT is added. Moreover, the earlier the diagnosis is finally established and treatment of CRPS I is initiated, the better the prognosis. Therefore, bone scintigraphy potentially has a major impact on patient management of this disorder.

Impact of [18F]FDG-PET on the primary staging of small-cell lung cancer.

PURPOSE: The purpose of this study was to evaluate the impact of [18F]fluorodeoxy-D-glucose positron emission tomography (FDG-PET) on the primary staging of patients with small-cell lung cancer (SCLC). METHODS: FDG-PET was performed in 120 consecutive patients with SCLC during primary staging. In addition, brain examinations with both FDG-PET and cranial magnetic resonance imaging (MRI) or computed tomography (CT) were performed in 91 patients. Results of FDG-PET were compared with those of conventional staging procedures. FDG-PET detected markedly increased FDG uptake in the primary tumours of all 120 patients (sensitivity 100%). RESULTS: Complete agreement between FDG-PET results and other staging procedures was observed in 75 patients. Differences occurred in 45 patients at 65 sites. In 47 sites the FDG-PET results were proven to be correct, and in ten, incorrect. In the remaining eight sites, the discrepancies could not be clarified. In 14/120 patients, FDG-PET caused a stage migration, correctly upstaging ten patients to extensive disease and downstaging three patients by not confirming metastases of the adrenal glands suspected on the basis of CT. Only 1/120 patients was incorrectly staged by FDG-PET, owing to failure to detect brain metastases. In all cases the stage migration led to a significant change in the treatment protocol. Sensitivity of FDG-PET was significantly superior to that of CT in the detection of extrathoracic lymph node involvement (100% vs 70%, specificity 98% vs 94%) and distant metastases except to the brain (98% vs 83%, specificity 92% vs 79%). However, FDG-PET was significantly less sensitive than cranial MRI/CT in the detection of brain metastases (46% vs 100%, specificity 97% vs 100%). CONCLUSION: The introduction of FDG-PET in the diagnostic evaluation of SCLC will improve the staging results and affect patient management, and may reduce the number of tests and invasive procedures.

Radioiodine therapy in hyperthyroidism: inverse correlation of pretherapeutic iodine uptake level and post-therapeutic outcome.

BACKGROUND: High iodine uptake levels are widely accepted as a condition for successful treatment with radioiodine (RAI). However, the existing data are controversial and the correlation of pretherapeutic RAI uptake level and outcome of RAI therapy has not yet been quantified. The aim of this study was to analyze the influence of RAI uptake on the outcome after RAI treatment and to estimate uptake-dependent success rates. MATERIALS AND METHODS: We retrospectively analyzed 229 patients (m = 53, f = 176; age 64 +/- 14 years) suffering from toxic adenoma, multinodular goitre or Graves' disease, respectively. Clinical status and T3, fT4 and TSH levels were assessed 3, 6, 12 and 18 months after treatment. Successful treatment was defined as loss of hyperthyroidism 18 months after radioiodine therapy. Logistic regression was used to assess the relation between the maximum iodine uptake and the rate of success and hypothyroidism, respectively, after RAI treatment. RESULTS: Overall, patients presented with pretherapeutic RAI uptake values between 17% and 100%. Eighteen months after RAI treatment, an euthyroid state was achieved in 136 patients (60%), hypothyroidism occurred in 47 patients (20%) and 46 patients (20%) remained hyperthyroid. The patients with the lowest pretherapeutic RAI uptakes showed the highest success rates. The overall success rate significantly decreased from 92% at low RAI uptakes to 57% at high uptakes (P = 0.002). This effect was found in the patients suffering from multinodular goitre as well as in the patients with Graves' disease. CONCLUSION: In contrast to the current opinion, our results provide evidence that the pretherapeutic iodine uptake level and post-therapeutic outcome are inversely correlated.

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.

[Appropriate uptake period for myocardial PET imaging with 18F-FDG after oral glucose loading]. / Optimaler Akquisitionszeitpunkt für die Herz-PET mit 18F-FDG nach oraler Glukosebelastung.

AIM: Identification of a rationale for the appropriate uptake period for myocardial (18)F-FDG-PET imaging of patients with and without diabetes mellitus. METHODS: In a subset of 27 patients, static 2D-PET examination was performed of patients with chronic coronary artery disease and known myocardial infarction. The patients fasted (at least 4 h) before examination. (18)F-FDG (330 +/- 20 MBq) was injected intravenously. The image quality was semiquantitativly determined by ROI-analysis and the myocardium-to-blood pool activity ratio (M/B) was calculated. I.) Scans 30, 60, and 90 min p. i. of 10 non-diabetic patients (60 g oral glucose loading one hour before FDG-injection, low-dose intravenous insulin bolus if necessary). II.) Scans 30, 60, and 90 min p. i. of 10 patients with known non-insulin dependent diabetes (20 g glucose, insulin bolus). III.) Scans 90 min p. i. of 7 patients with known non-insulin dependent diabetes and elevated fasting serum glucose level (140-200 mg/dl; insulin bolus, no glucose). RESULTS: I.) The M/B ratio significantly increases in nondiabetic patients with the uptake time (30 min 1.95 +/- 0.20; 60 min 2.96 +/- 0.36; 90 min 3.78 +/- 0.43). II.) In patients with non-insulin dependent diabetes the M/B ratio also significantly increases with uptake time. Compared to non-diabetic patients group II reached smaller M/B values (30 min 1.56 +/- 0.10; 60 min 2.15 +/- 0.14; 90 min 2.71 +/- 0.19). III.) In the group of patients with elevated fasting serum glucose level (who only got insulin but no glucose loading) the M/B activity ratio 90 min p. i. was clearly inferior compared with diabetic patients after oral glucose loading and insulin administration (M/B 2.71 +/- 0.19 versus 2.16 +/- 0.07). CONCLUSIONS: In static myocardial viability PET studies with (18)F-FDG an uptake time of 90 min yields image quality superior to that obtained after shorter uptake time.

Lymph node staging in extracranial head and neck cancer with FDG PET--appropriate uptake period and size-dependence of the results.

AIM: Identification of a rationale for the appropriate uptake period for static clinical extracranial head and neck PET imaging and evaluation of the diagnostic accuracy of such an optimized FDG PET approach for lymph node staging in the head and neck region. METHODS: In a subset of 5 patients, kinetic tumour studies were performed in order to identify the cellular activity plateau phase of FDG accumulation for head and neck cancer. Seventy-eight consecutive patients (11 women, 67 men; mean age +/- SD: 55 +/- 11 years; range, 36-78 years), presenting with histologically proven squamous cell carcinoma and sonographically detected lymph nodes in 86 neck sides, underwent clinically indicated FDG PET imaging. PET results were compared to those derived from histological examinations and follow-up imaging results after 6 months in order to calculate sensitivity and specificity for lymph node staging. RESULTS: FDG kinetics in head and neck cancer indicate that the cellular activity plateau of FDG accumulation is reached after an uptake period of 90 min. Using this protocol metastatic involvement of neck sides with lymph nodes less than 1 cm in diameter was correctly identified with a sensitivity of 71.4% and a specificity of 92.3%. Sensitivity increased with the lymph node diameter (1.1-1.5 cm 83.3%, 1.6-2.0 cm 100%, > 2 cm 88.9%). CONCLUSION: The appropriate uptake period for static clinical extracranial head and neck PET imaging that allows measurements in the activity plateau phase is about 90 min. FDG PET may add some significant information regarding metastatic spread into regional lymph nodes.

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.

Depressive state and regional cerebral activity in cancer patients - a preliminary study.

BACKGROUND: The aim of this study was to investigate influences of depressive states, chemotherapy and existence of remaining tumors on the regional brain activity of cancer patients. MATERIAL AND METHODS: Positron emission tomography with 18F-fluorodeoxyglucose was performed on 21 patients with various types of cancer. Their brain images were compared to 10 age- and gender-matched control data using statistical parametric mapping (SPM). The patients were subgrouped into the with and without depression based on the scores on Zung's self-rating depression scale (SDS), with and without previous chemotherapy, and with and without existence of remaining tumors. RESULTS: Significant metabolic reduction was detected in the cingulate gyrus, prefrontal, dorsolateral prefrontal, temporoparietal cortices and basal ganglia in cancer patients. These findings were close to known lesions of major depression. Intra-group comparisons showed that these hypometabolic findings were associated with the depth of depressive state. Influences of chemotherapy and remaining tumors on the cerebral cortex seemed to be weaker than that of psychological factors. CONCLUSIONS: The present pilot study suggests that frontal hypoactivity commonly seen in cancer patients is likely to be associated with depression rather than chemotherapy or remaining tumors. A brain mapping technique might be useful in evaluating neuropsychiatric problems in cancer patients.

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.

Radiopeptide transmitted internal irradiation of non-iodophil thyroid cancer and conventionally untreatable medullary thyroid cancer using.

AIM: Differentiated thyroid carcinomas (DTC) and medullary thyroid carcinomas (MTC) overexpress somatostatin receptor subtypes (sstr). The aim of this pilot study was to evaluate the tumour response of thyroid carcinomas to targeted irradiation with the radiolabelled somatostatin analogue [90Y]-1,4,7,10-tetra-azacyclododecan-4,7,10-tricarboxy-methyl-1-yl-acetyl-D-Phe1-Tyr3-octreotide ([90Y]-DOTA-D-Phe1-Tyr3-octreotide, or 90Y-DOTATOC) which has a high affinity to subtype 2 and a low affinity to subtype 5. It shows no affinity to sstr1, sstr3 and sstr4. PATIENTS AND METHODS: Twenty patients (mean age 58 years; 50% female, 50% male) with thyroid cancer were included (medullary thyroid cancer (MTC), 12 patients; differentiated thyroid cancer (DTC), seven patients; papillar carcinoma (PC), four patients; follicular carcinoma (FC), three patients; anaplastic carcinoma (AC), one patient). All patients had been therapy resistant and had progressive disease before 90Y-DOTATOC therapy. The dose applied was between totals of 1700 MBq x m(-2) to 7400 MBq x m(-2) 90Y-DOTATOC, administered in one to four injections at intervals of 6 weeks. In the case of tumour progression under therapy, treatment was terminated. RESULTS: The overall antitumour effect (objective response and stable disease) was 35%; in MTC 42%, in DTC 29%, and in AC 0%. The objective overall response rate was 0%. A stable disease was achieved in 35% (7/20), and progressive disease was found in 65% (13/20). The median time to progression was 8 months, with a median follow-up of 15 months. The treatment was very well tolerated. There were no grade III/IV haematological or renal toxicities. CONCLUSION: Targeted radiotherapy using 90Y-DOTATOC is able to stop tumour progression in a small number of patients and therefore may be an alternative treatment option for resistant disease. More significant tumour responses in thyroid and medullary thyroid cancer may be obtained by using radiopeptides with pan-somatostatin characteristics.

Increased metabolic activity in the thymus gland studied with 18F-FDG PET: age dependency and frequency after chemotherapy.

UNLABELLED: This study was designed to evaluate the age dependency of 18F-FDG uptake in the thymus and the frequency of PET confirmation of thymus hyperplasia after chemotherapy in cancer patients. METHODS: Whole-body FDG PET recordings of 168 patients were retrospectively examined for a retrosternal lesion in the anterior mediastinum that was attributable to the thymus. The patients were assigned to the following four groups: children with malignant lesions before the first therapy (group Ia; n = 15; mean age +/- SD, 11.9 +/- 3.7 y), children with malignant disease after chemotherapy (group Ib; n = 12; mean age, 10.3 +/- 5.0 y), adults with histologically confirmed malignant lymphoma before the first therapy (group IIa; n = 37; mean age, 43.9 +/- 16.7 y), and adult lymphoma patients 3 wk to 4 mo after chemotherapy (group IIb; n = 104; mean age, 40.9 +/- 14.6 y). RESULTS: Increased FDG accumulation in the thymus was seen in 11 patients (73%) of group Ia and 9 patients (75%) of group Ib. Thymus hyperplasia was found in 5 patients (5%) of group IIb. The eldest of these 5 patients was 25 y old. No increased FDG accumulation in the thymus was observed in any of the group IIa patients. In cases of visible FDG uptake in the thymus, standardized uptake values did not exceed 4. CONCLUSION: FDG accumulation in the thymus is a common finding in children and can occasionally be observed in young adults after chemotherapy. Knowledge of the characteristics of a typical retrosternal lesion in conjunction with the clinical history allows avoidance of diagnostic uncertainty and unnecessary procedures.

Radioisotope albumin flux measurement of microvascular lung permeability: an independent parameter in acute respiratory failure?

AIM: To evaluate the extent to which single measurements of microvascular lung permeability may be relevant as an additional parameter in a heterogenous clinical patient collective with Acute Lung Injury (ALI) and Acute Respiratory Distress Syndrome (ARDS). METHODS: In 36 patients with pneumonia (13), non pneumogenic sepsis (9) or trauma (14) meeting the consensus conference criteria of ALI or ARDS double-isotope protein flux measurements (51Cr erythrocytes as intravascular tracer, Tc-99m human albumin as diffusible tracer) of microvascular lung permeability were performed using the Normalized Slope Index (NSI). The examination was to determine whether there is a relationship between the clinical diagnosis of ALI/ARDS, impaired permeability and clinical parameters, that is the underlying disease, oxygenation, duration of mechanical ventilation and mean pulmonary-artery pressure (PAP). RESULTS: At the time of study, 25 patients presented with increased permeability (NSI > 1 x 10(-3) min-1) indicating on exudative stage of disease, and 11 patients with normal permeability. The permeability impairment correlated with the underlying disease (p > 0.05). With respect to survival, there was a negative correlation to PAP (p < 0.01). Apart from that no correlations between the individual parameters were found. Especially no correlation was found between permeability impairment and oxygenation, duration of disease or PAP. CONCLUSION: In ALI and ARDS, pulmonary capillary permeability is a diagnostic parameter which is independent from clinical variables. Permeability measurement makes a stage classification (exudative versus non exudative phase) of ALI/ARDS possible based on a measurable pathophysiological correlate.

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.

Exaggerated muscle mechanoreflex control of reflex renal vasoconstriction in heart failure.

In heart failure (HF) patients, reflex renal vasoconstriction during exercise is exaggerated. We hypothesized that muscle mechanoreceptor control of renal vasoconstriction is exaggerated in HF. Nineteen HF patients and nineteen controls were enrolled in two exercise protocols: 1) low-level rhythmic handgrip (mechanoreceptors and central command) and 2) involuntary biceps contractions (mechanoreceptors). Renal cortical blood flow was measured by positron emission tomography, and renal cortical vascular resistance (RCVR) was calculated. During rhythmic handgrip, peak RCVR was greater in HF patients compared with controls (37 +/- 1 vs. 27 +/- 1 units; P < 0.01). Change in (Delta) RCVR tended to be greater as well but did not reach statistical significance (10 +/- 1 vs. 7 +/- 0.9 units; P = 0.13). RCVR was returned to baseline at 2-3 min postexercise in controls but remained significantly elevated in HF patients. During involuntary muscle contractions, peak RCVR was greater in HF patients compared with controls (36 +/- 0.7 vs. 24 +/- 0.5 units; P < 0.0001). The Delta RCVR was also significantly greater in HF patients compared with controls (6 +/- 1 vs. 4 +/- 0.6 units; P = 0.05). The data suggest that reflex renal vasoconstriction is exaggerated in both magnitude and duration during dynamic exercise in HF patients. Given that the exaggerated response was elicited in both the presence and absence of central command, it is clear that intact muscle mechanoreceptor sensitivity contributes to this augmented reflex renal vasoconstriction.

Limbic encephalitis investigated by 18FDG-PET and 3D MRI.

Two patients with clinically probable or possible limbic encephalitis (LE) are reported, both cases with typical findings in clinical symptoms (severe neuropsychological deficits and complex partial seizures) and in routine magnetic resonance imaging (MRI) (hyperintense mesiotemporal lesions). Underlying malignancy was identified (rectal carcinoma) in one case but could not be detected in the other patient. The 2 patients were investigated by cerebral 18F-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) and 3-dimensional (3D) MRI, and abnormalities in metabolic activity were mapped using coregistration of spatially normalized PET and MRI. Highly significant focal hypermetabolism in bilateral hippocampal areas was found in both cases. The authors' findings support FDG-PET coregistered to 3D MRI as a potentially valuable additional tool in the imaging diagnostics of LE. Results are discussed with respect to the clinical symptoms and previously reported imaging findings in the disease.

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.

[Nuclear medicine diagnosis of kidney function in unilateral urinary tract dilatation in childhood]. / Nuklearmedizinische Nierenfunktionsdiagnostik bei unilateraler Harntraktdilatation im Kindesalter.

Ultrasound accurately detects hydronephrosis in infants and children, while nuclear medicine techniques quantify relative renal function in addition to characterize the urodynamic relevance of hydronephrosis. Because ultrasound fails to estimate the potential reduction of relative kidney function with more severe hydronephrosis and moreover, renal function is not necessarily affected by hydronephrosis, renal scintigraphy is indicated to assess the functional status of hydronephrotic kidneys for both, split renal function and postrenal urine drainage without and, if necessary, with furosemide intervention.

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.