Incidental diagnosis of a PSA-negative prostate cancer by 18FDG PET/CT in a patient with hypopharyngeal cancer.

Diagnosis of prostate cancer (PC) still remains critical as non-invasive screening with prostate specific-antigen (PSA) lacks to indicate malignancy of the prostate in some cases. Recent research has shown that clinically meaningful PC can develop in patients with a PSA value <4 ng/ml, frequently defined as upper limit of normal serum PSA levels. Furthermore, both morphological (computed tomography (CT), magnetic resonance imaging, transrectal ultrasound) and functional imaging with (18)fluorodeoxyglucose positron emission tomography (FDG-PET) are associated with several limitations for primary diagnosis of PC. We report a case of an incidentally diagnosed PSA-negative PC by (18)FDG PET/CT in a patient with a previous diagnosis of a hypopharyngeal cancer.

(18)F-FDG PET and conventional imaging for assessment of Hodgkin's disease and non Hodgkin's lymphoma. An analysis of 193 patient studies.

UNLABELLED: The AIM of this study was to assess the diagnostic value of FDG-PET and conventional imaging (CI) in a large series of patient with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) at three time points during their course of disease. PATIENTS, METHODS: 169 consecutive lymphoma patients (69 HD; 100 NHL) were included. 193 FDG-PET studies were performed for staging at baseline in 42 cases, for post-therapeutic monitoring in 103, and for diagnosis of recurrence in 48 cases. Performance indices of sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and accuracy of metabolic FDG-PET and morphological CI were calculated. Differences in staging and diagnosis of residual or recurrent lymphoma were compared. RESULTS: FDG-PET changed staging in 36% of cases for staging at baseline, in 52% of cases for monitoring response to treatment, and in 29% for diagnosis of recurrence. FDG-PET staging results were confirmed in 80% for staging at baseline, in 74% for monitoring response to treatment, and in 50% for diagnosis of recurrence. FDGPET and CI differed significantly at monitoring response to treatment for sensitivity (0.91 versus 0.69; p < 0.02), specificity (0.90 versus 0.38; p < 0.00001), PPV (0.77 versus 0.42; p < 0.001), and accuracy (0.83 versus 0.55; p < 0.02). CONCLUSION: FDG-PET should be considered as the diagnostic modality of choice for post-therapeutic assessment of lymphoma patients and may be a reliable alternative to CI for staging at baseline and diagnosis of recurrence.

Dopamine transporter SPECT in patients with mitochondrial disorders.

BACKGROUND: Mitochondrial disorders may affect basal ganglia function. In addition, decreased activity of complex I of the mitochondrial electron transport chain has been linked to the pathogenesis of dopaminergic cell loss in Parkinson's disease. Objective : To investigate the dopaminergic system in patients with known mitochondrial disorders and complex I deficiency. METHODS: Dopamine transporter density was studied in 10 female patients with mitochondrial complex I deficiency by (123)I-FP-CIT (N-beta-fluoropropyl-2beta-carbomethyl-3beta-(4-iodophenyl)-nortropane) SPECT. RESULTS: No differences in (123)I-FP-CIT striatal binding ratios were observed and no correlation of the degree of complex I deficiency and striatal binding ratios could be detected. CONCLUSIONS: These data argue against the possibility that mitochondrial complex I deficiency by itself is sufficient to elicit dopaminergic cell loss.

Neuroimaging and 5-HT2C receptor polymorphism: a HMPAO-SPECT study in healthy male probands using mCPP-challenge of the 5-HT2C receptor.

BACKGROUND: The human 5-HT (2C) receptor gene has been localized on the X chromosome and is expressed in two genetic variants. Whereas previous investigations have suggested that the 5-HT (2C) receptor gene polymorphism is critically involved in the pathogenesis of affective and eating disorders, as yet the functional consequences being associated with the rare serine variant of the 5-HT (2C) receptor in humans are unclear. METHODS: We explored by HMPAO-SPECT if a challenge with the serotonin agonist mCPP, that interacts mainly with the 5-HT (2C) receptor, provokes different patterns of regional cerebral bloodflow (rCBF) as a function of the genetic variant of the receptor. Thus we studied its action in 16 healthy male volunteers carrying the common 5-HT (2C)-cys-23 receptor gene and 16 healthy male volunteers carrying the less frequent 5-HT (2C)-ser-23 receptor gene. RESULTS: We found significant differences in rCBF between the two genotypes after mCPP infusion compared to placebo: In the cysteine group rCBF was increased in the left medial prefrontal cortex and decreased in the left anterior cingulate and right medio-temporal cortex, whereas the serine group showed an increase of rCBF in the left medio- and superior-temporal cortex and in cerebellum and a reduced rCBF in the right medial prefrontal cortex. In addition, there was a significant disordinal interaction of the genotype factors and challenge with an increase of rCBF in the serine group and a decrease in the cysteine group in the left motor cortex and calcarine cortex. Additionally, a decrease of rCBF in the serine-group and a simultaneous increase in the cysteine group was found in the right anterior and the left posterior cingulate cortex. CONCLUSION: These findings suggest that differences in the 5-HT (2C) receptor gene polymorphism has functional consequences due to a different responsiveness of the expressed 5-HT (2C) receptor variants.