Egbert U. Nitzsche

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

PurposeThe 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).MethodsFDG-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%).ResultsComplete 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%).ConclusionThe 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.

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

Abstract. 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 (6× limited disease, 12× extensive disease, 5× 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.

Non-invasive differentiation of pancreatic lesions: is analysis of FDG kinetics superior to semiquantitative uptake value analysis?

Abstract The diagnostic utility of fluorine-18 2-deoxy-D-glucose positron emission tomography (FDG PET) for the non-invasive differentiation of focal pancreatic lesions originating from cancer or chronic pancreatitis by combined visual image interpretation and semiquantitative uptake value analysis has been documented. However, in clinical routine some misdiagnosis is still observed. This is because there is potential overlap between the semiquantitative uptake values obtained for active inflammatory lesions and cancer. Therefore, this prospective study was undertaken to test the hypothesis that analysis of dynamic kinetics of focal pancreatic lesions based on FDG PET may more accurately determine the benign or malignant nature of such lesions. Thirty patients (56±17 years) were studied dynamically with FDG PET for a period of 60–90xa0min. Patients were assigned to one of four groups: control, acute pancreatitis, chronic pancreatitis or pancreatic cancer. Two observers, blinded to the clinical data, analysed the time-activity curves of FDG kinetics based on region of interest analysis. The diagnosis predicted by FDG PET was compared with the result of histological examination of the surgical specimen. Analysis of FDG kinetics revealed significant differences in the shape of the time-activity curve for controls, pancreatic cancer and inflammatory disease. Surprisingly, there was no significant difference in the time-activity curve shape for chronic pancreatitis and acute pancreatitis; this is, however, not a clinical issue. Furthermore, acquisition time (60xa0min vs 90xa0min) did not affect interpretation of the time-activity curve, so that scanning time may be regularly shortened to 60xa0min. Interobserver agreement was 1. Based on these findings, non-invasive differentiation between pancreatic cancer and chronic pancreatitis was correctly predicted in all cases, as confirmed by histology. In addition, the specificity was increased compared with that obtained from standardised uptake value analysis. Non-invasive differentiation between pancreatic cancer and chronic pancreatitis may best be achieved based on a dynamic FDG PET study including kinetic analysis. This approach yields results superior to those obtained from a semiquantitative analysis of pancreatic lesions.

Imaging and Imaging-Guided Intervention of the Parathyroid Glands

Primary hyperparathyroidism (HPTH) is often diagnosed accidentally as asymptomatic disease, when hypercalcemia and elevated PTH level are observed based upon a laboratory test. However, if a more vigorous patient’s history is taken, non-specific symptoms such as tiredness and irritation are frequently observed. In the majority of patients presenting with HPTH, cortical bone density is reduced, especially if measured at the distal radius. In about 80% of patients, a benign solitary parathyroid adenoma (PA) represents the cause of disease. Fourteen percent of patients present with multiple adenomas, in 5% hereditary forms of HPTH appear causative. In about 1% of cases, a parathyroid carcinoma is finally diagnosed.

Diagnostic Imaging of the Thyroid and Radioiodine Therapy

According to its superficial anatomic location, the thyroid gland may easily be assessed by sonography. Linear transducers with a width of 7.5–9 cm and frequencies of around 10 MHz are used. Sonography of the thyroid gland should also always be combined with a sonography of the surrounding soft tissues and of the cervical vessels. It allows the exact measurement of the thyroid volume and assessment of the parenchymal texture of the thyroid gland with identification of diffuse or focal abnormalities of the gland itself and of potential abnormalities within the surrounding structures.

Appropriate uptake period for myocardial PET imaging with 18 F-FDG after oral glucose loading

AIMnIdentification of a rationale for the appropriate uptake period for myocardial (18)F-FDG-PET imaging of patients with and without diabetes mellitus.nnnMETHODSnIn 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).nnnRESULTSnI.) 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).nnnCONCLUSIONSnIn 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.