18 F-FDG is in widespread use in cancer imaging but has limited utility in staging and monitoring of prostate cancer. 1-11 CLabeled acetate, a substrate for the citric acid cycle, is superior. The kinetics of prostate tumors were investigated. Methods: Ten patients with primary prostate cancer, 10 with recurrent tumor, and 2 men with benign prostate hypertrophy were studied. After administration of 5.5 MBq/kg 1-11 C-acetate, dynamic PET of the pelvis was acquired for 20 min. Images were reconstructed with iterative algorithms, and corrections for attenuation and scatter were applied. Factor analysis produced factor images, representing iliac vessels and the prostate from which blood-input and tissue-output functions were derived with simple thresholding techniques. Five different kinetic models were applied to the dynamic data to estimate the rate constants. Results: The standard 3-compartment, 2-tissue model was able to describe 1-11 C-acetate kinetics of the prostate. The model could be reduced to 3 parameters by setting the tissue blood fraction and release from the second tissue compartment (k 4 ) to zero. Correction for metabolites appeared to be necessary. This reduced model performed marginally better than a 2-compartment model. A significant correlation was found between the influx rate constant (K) and acetate uptake (standardized uptake value) for primary tumors (r 5 0.91), whereas there was no correlation for recurrent tumors (r 5 20.17). Patlak graphical analysis provided accurate parameter estimates. Conclusion: A 3-compartment, 3-parameter model is able to describe adequately the acetate kinetics in prostate cancer. Significant differences between primary and recurrent cancer were found for transport k 1 , influx K, distribution volume V d , as well as early (6-10 min) and late (15-20 min) 1-11 C-acetate uptake.

We sought to identify magnetic resonance-(MR)-imaged structures associated with declarative memory in a community-dwelling sample of elderly Mexican-American individuals with a spectrum of cognitive decline. Measured structures were the hemispheric volumes of the hippocampus (HC), parahippocampal gyrus, and remaining temporal lobes, as well as severity of white matter signal hyperintensities (WMH). Participants were an imaged subsample from the Sacramento Area Latino Study of Aging (SALSA), N 5 122. Individuals were categorized as normal, memory impaired (MI), cognitively impaired non-demented (CIND), or demented. We show that WMH was the strongest structural predictor for performance on a delayed free-recall task (episodic memory) in the entire sample. The association of WMH with delayed recall was most prominent in elderly normals and mildly cognitively impaired individuals with no dementia or impairment of daily function. However, the left HC was associated with verbal delayed recall only in people with dementia. The right HC volume predicted nonverbal semantic-memory performance. We conclude that WMH are an important pathological substrate that affects certain memory functions in normal individuals and those with mild memory loss and discuss how tasks associated with WMH may rely upon frontal lobe function. (JINS, 2004, 10, 371-381.)

Objective To compare values of urodynamic measurements of cats with idiopathic cystitis (IC) with previously published data for healthy female cats. Animals 11 female cats with IC. Procedures 2 sequential cystometrograms and 2 urethral pressure profiles were obtained for each cat. All tracings were evaluated for evidence of overactive urinary bladder (OAB). Maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP), and functional profile length were recorded. Results Only 3 cats had obvious micturition events. None of the 11 cats had evidence of OAB. Although not significant, threshold pressure was lower in cats with IC than in healthy cats (mean ± SD, 89.0 ± 12.0 cm H2O vs 75.7 ± 16.3 cm H2O, respectively); however, the total volume infused was significantly lower in cats with IC (4.8 ± 2.1 mL/kg vs 8.3 ± 3.2 mL/kg). The MUCP was significantly higher in cats with IC than in healthy cats (158.0 ± 47.7 cm H2O vs 88.9 ± 23.9 cm H2O, respectively). The MUP was also significantly higher in all portions of the urethra in cats with IC. Conclusions and Clinical Relevance No evidence of OAB was identified in any cat evaluated; therefore, medications used to target this abnormality did not appear justified. The high MUCP in cats with IC suggested that α1-adrenoceptor antagonists or skeletal muscle relaxants may be useful in this disease, and if these data were applicable to male cats, then α1-adrenoceptor antagonism may help prevent recurrent obstructive IC. Further studies are indicated to determine the effects, if any, these drugs might have in cats with IC.

No abstract