2-Deoxy-2-[F-18]fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose-Positron Emission Tomography Sensitivity to Serum Glucose: A Survey and Diagnostic Applications

OBJECTIVE: The positron emission tomography (PET) clinical utility of the sensitivity (gamma) of uptake (Q) to a change in plasma glucose concentration (C) is investigated. METHODS: Gamma is obtained from data as [ln(Q (2)/Q (1))] / [ln(C(2)/C(1))], using previously published intrapatient studies varying C within a single patient and some interpatient ones. It can be theoretically related to the half-saturation constant in the Michaelis-Menten quantification of competitive uptake. One of its uses is making uptake corrections for desired vs. actual C using Q(2) = Q(1) (C(2)/C(1))(gamma). RESULTS: Intrapatient studies proved to be preferable to interpatient ones, and a 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-PET survey with analyses for gamma yielded the following result: usually the gamma values of tumors and brain tissues were near -1, whereas those of other noncerebral tissues were near 0. Regarding correcting uptakes for C, instead of a universally assumed and applied gamma = -1, corrections should be for a single tissue using its known gamma. An advantageous use of gamma is predicting how C affects image contrast, including where glucose loading is sometimes preferable to fasting. CONCLUSIONS: A potentially useful quantifier of uptake sensitivity to plasma glucose has been defined and values obtained. Correcting uptakes to some standard C requires special care. gamma can help PET clinicians select fasting or loading to achieve glucose levels for optimum contrast.     

Spectrophotometric plasma iron determination from fingerpuncture specimens

A simple, sensitive, precise and reproducible micromethod for the determination of plasma iron in a 50-μl sample has been devised by modification of the ICSH reference procedure, which requires a 2-ml sample. The micromethod uses microcuvettes and substitutes ferrozine for the bathophenanthroline chromogen of the ICSH. Comparison of plasma iron values on 47 paired specimens obtained by fingerpuncture and venipuncture determined by the micro- and ICSH-methods respectively gave identical means of 15.8 μmol/l (88 μg/dl); the correlation of the two methods was r = 0.92 (p < 0.0001). The micro-method has been successfully used to measure plasma iron levels in fingerpuncture specimens collected in a field study of 429 children.     

A stroke volume-based fluid resuscitation protocol decreases vasopressor support and may increase organ yield in brain-dead donors

Brain-dead donors are frequently hypovolemic and hypotensive requiring vasopressor support. We studied a stroke volume-based fluid resuscitation and vasopressor weaning protocol prospectively on 64 hypotensive donors, with a recent control cohort of 30 hypotensive donors treated without a protocol. Stroke volume was measured every 30 minutes for 4 hours by pulse contour analysis or esophageal Doppler. A 500 mL saline fluid bolus was infused over 30 minutes and repeated if the stroke volume increased by 10%. No fluid was infused if the stroke volume did not increase by 10%. Vasopressors were weaned every 10 minutes if the mean arterial pressure was greater than 65 mm Hg. The protocol group received 1937 ± 906 mL fluid compared to 1323 ± 919 mL in the control group (P = .003). Mean time on vasopressors was decreased from 957.6 ± 586.2 to 176.3 ± 82.2 minutes (P<.001). Donors in the protocol group were more likely to donate four or more organs than donors in the control group (OR = 4.114, 95% Confidence Interval (CI) = 1.003-16.876). While more organs were transplanted per donor in the protocol group (3.39 ± 1.52) than in the control group (2.93 ± 1.44) (P = .268), the difference did not reach statistical significance. A goal-directed fluid resuscitation protocol decreased organ ischemia and may increase organs transplanted.     

Individualized pelvic physical therapy for the treatment of post-prostatectomy stress urinary incontinence and pelvic pain

International Urology and Nephrology - The rehabilitation of post-prostatectomy urinary incontinence has traditionally focused on pelvic floor strengthening exercise. The goal of this study was to...     

Case report of a de novo brainstem arteriovenous malformation in an 18-year-old male and review of the literature

De novo intracerebral arteriovenous malformations (AVMs) are exceedingly rare with only seven reported cases in the literature. Although generally considered congenital by nature, the lesions do not manifest themselves clinically until the third or fourth decades of life. However, with the advent of improved imaging modalities and more frequent surveillance, an increasing number of de novo cases are being found challenging the concept AVMs develop in the perinatal/antenatal period. Alternatively, this phenomenon could represent a distinct entity in which lesion development occurs after birth. A PubMed search of “de novo cerebral arteriovenous malformation” was performed in which seven reported cases were found. The mean age at diagnosis was 14.7 years with a mean follow-up imaging study of 5.8 years. Lesion location was supratentorial in all previously described cases. This case involves an 18-year-old male with congenital hydrocephalus and seizures diagnosed at 7 months of age. The patient underwent a ventriculoperitoneal shunt and was followed frequently by a neurologist. The last diagnostic imaging was an unremarkable MRI of the brain at age 12. Seven years later, the patient presented with an intracerebral hemorrhage. A CT angiogram demonstrated a large brainstem AVM with an intraparenchymal hemorrhage and intraventricular extension. This case is unique in that it is the first infratentorial de novo AVM. The congenital nature of AVMs is challenged with the increasingly described series of patients with previously documented normal radiographic imaging. This suggests there may be a subset of patients genetically predisposed to postnatal development of AVMs.