Digital filtering of the bladder in SPECT bone studies of the pelvis

A data processing technique for the removal of bladder activity from single photon emission computed tomographic bone studies of the pelvis has been developed. The method involves the replacement of count values in the bladder on all projection views by data which are representative of the activity in surrounding structures. Reconstruction is then performed using the amended set of projection views. The method was tested by examining a group of 13 patients referred for investigation of avascular necrosis of the femoral head. Significant improvements in image quality were observed, particularly with respect to the level of artifact production, which increased the number of cases in which a confident and correct diagnosis was made.     

Comparison of the forearm and calf blood flow response to thermal stress during dynamic exercise.

To examine the hypothesis that the skin blood flow response to body heating is not uniform over the entire body surface, we compared forearm (FBF) and calf (CBF) blood flow responses to an increase in core temperature (esophageal temperature, Tes) during dynamic exercise. We studied 13 physically active men during semi-recumbent one leg exercise and/or intermittent supine cycle exercise at 35 degrees C. During 30 min of one leg exercise, Tes, FBF, and CBF in the nonactive leg increased from 36.94 +/- 0.09 degrees C, 5.7 +/- 1.2, and 5.6 +/- 0.6 ml.(min.100 ml)-1 at rest to 37.97 +/- 0.10 degrees C, 27.0 +/- 2.4, and 11.1 +/- 0.8 ml.(min.100 ml)-1, respectively. The increase in blood flow per unit increase in Tes was much less in the calf than in the forearm. The ratio of the peak to resting blood flow averaged 6.5 in the forearm and 2.5 in the calf. During 60 min of intermittent supine two leg exercise, Tes, FBF, and CBF increased from 36.96 +/- 0.06 degrees C, 7.9 +/- 1.5, and 5.6 +/- 0.7 ml.(min.100 ml)-1 at rest to 37.91 +/- 0.07 degrees C, 23.6 +/- 3.0, and 11.4 +/- 1.9 ml.(min.100 ml)-1, respectively. Skin blood flow (SkBF) in the forearm and calf was estimated by using a simple cylindrical model, assuming skin thickness and resting muscle blood flow to be 0.2 cm and 2 ml.(min.100 ml)-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prediction of malignant potential in reflux disease

There is interest in noninvasive means of identifying reflux patients at increased risk of developing Barrett's esophagus and adenocarcinoma. In this issue, Gough et al. studied the prevalence of polymorphisms of cytokine genes in patients with uncomplicated esophagitis versus Barrett's/esophageal adenocarcinoma. They reported a difference between the groups with respect to the interleukin-1 receptor antagonist and interleukin-10 genes. However, the number of comparisons carried out mean that the association is not statistically significant and further studies will be required to confirm/refute the association. The genetic markers reported would unfortunately be of little value in predicting individual risk of esophageal adenocarcinoma as they are weak predictors and relatively rare within the esophagitis population. The findings of this study demonstrate the general principle that polymorphisms of individual genes are of limited value in identifying patients at risk of sporadic-types of cancer such as most cases of esophageal adenocarcinoma.     

Minimum 6-year outcomes for interstitial cystitis treated with sacral neuromodulation

Introduction and hypothesis  

Interstitial cystitis is a multifaceted medical condition consisting of pelvic pain, urgency, and frequency. Can sacral neuromodulation be successfully utilized for the medium term of ≥6 years in interstitial cystitis patients for whom standard drug therapies have failed?     

The Clinical Research Tool: A High-Performance Microdialysis-Based System for Reliably Measuring Interstitial Fluid Glucose Concentration

Background

A novel microdialysis-based continuous glucose monitoring system, the so-called Clinical Research Tool (CRT), is presented. The CRT was designed exclusively for investigational use to offer high analytical accuracy and reliability. The CRT was built to avoid signal artifacts due to catheter clogging, flow obstruction by air bubbles, and flow variation caused by inconstant pumping. For differentiation between physiological events and system artifacts, the sensor current, counter electrode and polarization voltage, battery voltage, sensor temperature, and flow rate are recorded at a rate of 1 Hz.

Method

In vitro characterization with buffered glucose solutions (c_glucose = 0 - 26 × 10^-3 mol liter^-1) over 120 h yielded a mean absolute relative error (MARE) of 2.9 ± 0.9% and a recorded mean flow rate of 330 ± 48 nl/min with periodic flow rate variation amounting to 24 ± 7%. The first 120 h in vivo testing was conducted with five type 1 diabetes subjects wearing two systems each. A mean flow rate of 350 ± 59 nl/min and a periodic variation of 22 ± 6% were recorded.

Results

Utilizing 3 blood glucose measurements per day and a physical lag time of 1980 s, retrospective calibration of the 10 in vivo experiments yielded a MARE value of 12.4 ± 5.7. Clarke error grid analysis resulted in 81.0%, 16.6%, 0.8%, 1.6%, and 0% in regions A, B, C, D, and E, respectively.

Conclusion

The CRT demonstrates exceptional reliability of system operation and very good measurement performance. The ability to differentiate between artifacts and physiological effects suggests the use of the CRT as a reference tool in clinical investigations.