Comparing 0.2 tesla with 1.5 tesla intraoperative magnetic resonance imaging analysis of setup, workflow, and efficiency

RATIONALE AND OBJECTIVES: To compare low-field with high-field intraoperative magnetic resonance imaging (MRI) in respect to setup, workflow, and efficiency. MATERIALS AND METHODS: A total of 750 patients were investigated either with a 0.2 T (March 1996-July 2001) or a 1.5 T (April 2002-August 2004) MRI system adapted for intraoperative use. RESULTS: With the low-field setup, 330 patients were examined in 65 months; with the high-field setup, 420 patients were examined in 29 months, which is a 2.8-fold increase in cases per month (14.5 versus 5.1) reflecting improved ease of use. Concerning intraoperative workflow, the time for preparation to start intraoperative imaging decreased fivefold (2 minutes instead of 10 minutes); navigation was applied more often with 57% versus 51% (240/420 versus 167/330), whereas functional data were integrated in 35% versus 39% (84/240 versus 65/167). Application of navigation updates was doubled (22% versus 11%; 53/240 versus 18/167). Image acquisition time was reduced by a factor of two, allowing a more detailed imaging protocol, whereas the image quality is clearly improved in the high-field setup, where there was no difference between the standard preoperative image quality compared with the intraoperative quality. This contributed to an increased detection of tumor remnants and extended resections in pituitary (36% versus 29%; 47/129 versus 17/59) and glioma surgery (41% versus 26%; 38/93 versus 28/106). CONCLUSION: Compared with the low-field setup, the high-field setup results not only in clearly superior image quality and increased imaging armamentarium, contributing to increased rates of detected tumor remnants, but also in a distinct improvement of intraoperative workflow. Furthermore, intraoperative high-field MRI offers various modalities beyond standard anatomic imaging, such as magnetic resonance spectroscopy, diffusion tensor imaging, and functional MRI.     

Pilot study of neuraxial imaging by ultrasound in infants and children

BACKGROUND: Ultrasonography is becoming an important adjunct in regional anesthesia. Epidural anesthesia may pose significant challenges in infants and children because of difficulties in identifying the epidural space. In addition, epidural catheters are sometimes difficult to advance. The present study was performed to evaluate an optimal ultrasound technique for direct visualization of neuraxial structures in children. METHODS: A total of 32 infants and children scheduled for minor surgery were prospectively included in a high-resolution ultrasound study. Scans were performed using either a sector or linear probe and views from a longitudinal paramedian, median and transversal angle at lumbar and thoracic levels of the spinal cord were analyzed. RESULTS: In all children investigated, the linear probe generated better images than the sector probe. Of the various scanning perspectives, the paramedian longitudinal approach offered the best views at both cord levels. Broken down by age groups, the best visibility was clearly obtained in neonates up to 3 months of age (P < 0.0001 Vs all other age groups). In older children, the quality of ultrasound decreased in an age-dependent manner. CONCLUSIONS: Paramedian longitudinal scans with linear probes are the most favorable method of imaging neuraxial anatomy at lumbar and thoracic cord levels in infants and children, with the best results in neonates up to 3 months of age. Based on these results, and using real time imaging, a practical technique for ultrasound-guided epidural anesthesia for neonates and infants at lumbar and thoracic levels of the spinal cord is planned.     

Late relapse of testicular germ cell neoplasms: a descriptive analysis of 122 cases

PURPOSE: The problem of late relapse of testicular germ cell tumor (GCT) is poorly understood. No more than approximately 300 cases have been reported to date. It appears that late relapse (L/R) of GCT involves a more aggressive biology than virginal GCT. In the present study we increased the understanding of L/R by analyzing these events in a large patient sample. MATERIALS AND METHODS: Late relapse was defined as recurrence of disease more than 2 years after completion of primary treatment. A total of 122 patients (50 with pure seminoma and 72 with nonseminoma) were retrospectively studied. Several parameters were analyzed including age, clinical stage, treatment at primary presentation, occurrence of prior early relapse, interval to L/R, tumor markers, site of relapse, and mode and outcome of L/R treatment. Possible effects of various clinical parameters on treatment results were studied by multivariate statistical analysis. RESULTS: Median age at first presentation was 34 years and 26.5 years in patients with seminoma and nonseminoma, respectively. The intervals to L/R were 42 months (range 25 to 276) in seminoma and 64.5 months (range 28 to 216) in nonseminoma. A total of 75% of nonseminomas but only 20% of seminomas had disseminated disease at first presentation, while 51 patients with nonseminoma had initially received chemotherapy. alpha-Fetoprotein was increased in 45 patients (of 59 eligible) with nonseminoma at L/R, human chorionic gonadotropin in 12 cases. alpha-Fetoprotein levels greater than 100 U/l indicated poor prognosis. Topographically relapses were mainly confined to lymph nodes of the abdomen, chest and neck. Of 72 patients with nonseminoma cure failed in 37 in contrast to only 6 patients with seminoma (of 48 eligible). Inclusion of surgery increased the chance of cure (RR 4.0, 95% confidence interval 0.9-18.5). CONCLUSIONS: Late relapses of GCT are biologically and clinically distinct from virginal GCT. These events occur in nonseminoma and seminoma, but clinical features are quite different in the 2 groups. Increase of alpha-fetoprotein is typical in late relapsing nonseminoma and levels of more than 100 U/l appear to indicate poor prognosis. Anatomically L/R presents as lymphadenopathy of abdomen, chest or neck. Treatment should include surgery in nonseminoma. Seminomas and otherwise chemotherapy naive cases might respond to chemotherapy only. Particular risk groups for late relapse are nonseminoma with prior early relapse, patients receiving chemotherapy for disseminated disease at first presentation and those with pure teratoma. These latter subgroups should be followed with annual health examinations for at least 10 years.     

Resuscitation-induced gut edema and intestinal dysfunction

BACKGROUND: Mesenteric venous hypertension and subsequent gut edema play a pivotal role in the development of intra-abdominal hypertension. Although gut edema is one cause of intra-abdominal hypertension, its impact on gut function is unknown. The purpose of this study was to create a model of acute hydrostatic gut edema and to evaluate its effect on gut motility and barrier function. METHODS: The first study, group A, evaluated the effect of gut edema on transit over time using 20 mL/kg 0.9% saline. The second study, group B, focused on the 12-hour time period using 80 mL/kg 0.9% saline. Rats were randomized to superior mesenteric vein partial occlusion (venous hypertension) or sham surgery. At 6, 12, and 24 hours, group A underwent intestinal transit and tissue water weight measurements. At 12 hours, group B underwent tissue water, transit, ileal permeability and resistance, lactate and myeloperoxidase activity, and mucosal injury measurements. RESULTS: Venous hypertension with fluid resuscitation caused acute hydrostatic gut edema, delayed intestinal transit, increased mucosal permeability to macromolecules, and decreased tissue resistance over time. Mucosal injury was minimal in mesenteric venous hypertension. CONCLUSION: Acute mesenteric venous hypertension and resuscitation-induced gut edema, in the absence of ischemia/reperfusion injury, is associated with delayed intestinal transit and altered gut barrier function.     

A prospective analysis of the time to normalization of serum androgens following 6 months of androgen deprivation therapy in patients on a randomized phase III clinical trial using limited hormonal therapy

PURPOSE: Patients with prostate cancer are treated with neoadjuvant, adjuvant and intermittent therapy with gonadotropin-releasing hormone agonists (GnRH-A). While these are largely successful in decreasing testosterone (T) and dihydroxytestosterone (DHT) to castrate levels, discontinuation of such therapy often results in continued suppression of androgens for variable periods of time. We present the largest published series of patients evaluating the timing of T and DHT increase after cessation of GnRH therapy. MATERIALS AND METHODS: Serial T and DHT measurements were prospectively obtained every 3 months while on GnRH-A then monthly upon discontinuation of GnRH-A. Analysis of time from the second 3-month GnRH-A administration to T and DHT increase was undertaken. RESULTS: A total of 80 evaluable patients had a median time to T 50 ng/dl or greater of 12.9 weeks and a median time to T normalization (212 ng/dl or greater) of 16.6 weeks. Low baseline T was associated with a prolonged time to T 212 ng/dl or greater (p = 0.0086) and a similar trend was seen in patients older than 66 years (p = 0.08). There were 62 evaluable patients with a median of 14.9 weeks to DHT 150 pg/ml or greater. There was no association with Gleason score at diagnosis, on study prostate specific antigen, type of prior definitive therapy, or any prior hormonal therapy and time to increase in circulating androgens. CONCLUSIONS: After 6 months of GnRH-A therapy in these patients, DHT and T levels did not return to normal for a median of 14.9 and 16.6 weeks, respectively.     

Cholinergic and purinergic responses in isolated human detrusor in relation to age

PURPOSE: We investigated whether the contractility of isolated human detrusor muscle, responsiveness to commonly used spasmolytic drugs, and expression of selected muscarinic and purinergic (P2X) receptor subtypes (M2, M3, P2X1 and P2X3) change with age. MATERIALS AND METHODS: Tissues were taken from 63 patients 37 to 84 years old undergoing radical cystectomy. Specimens from 49 patients were used for contractility studies and those from 50 were used for mRNA analysis. RESULTS: Propiverine, oxybutynin, tolterodine and atropine decreased contractions evoked by electric field stimulation to different degrees. However, neither the efficacy nor potency of the drugs showed age related changes. Since human detrusor muscle shows atropine resistant noncholinergic responses, we also studied the putative age dependence of concentration-response curves to the muscarinic agonist carbachol, and the purinergic agonists adenosine triphosphate (ATP) and alpha-beta-methylene-ATP. Sensitivity to alpha-beta-methylene-ATP increased with age, while the efficacy and potency of spasmolytic drugs did not depend on age. In addition, mRNA detected for M2, M3, P2X1 and P2X3 receptors did not change with age. CONCLUSIONS: Our results do not provide evidence for age related contractile deterioration in human detrusor muscle strips, nor do they suggest that responses to anticholinergic spasmolytic drugs change substantially with age.     

Preteen attitudes about smoking and parental factors associated with favorable attitudes

PURPOSE: To describe youth smoking-related attitudes and evaluate the effects of parental factors on child adoption of positive attitudes about smoking. DESIGN: This study used baseline and 20-month data from a family-based smoking-prevention study (82.9% completed both surveys). SETTING: Telephone recruitment from two health maintenance organizations. SUBJECTS: Children aged 10 to 12 years and one parent of each child (n=418 families) were randomly assigned to a frequent assessment cohort (12.5% of participants). Intervention. Families received a mailed smoking-prevention packet (parent handbook, videotape about youth smoking, comic book, pen, and stickers), outreach telephone counselor calls to the parent, a newsletter, and medical record prompts for providers to deliver smoking-prevention messages to parents and children. MEASURES: Demographics, tobacco status, attitudes about smoking (Teenage Attitudes and Practices Survey), family discussions about tobacco, family cohesiveness (family support and togetherness), parent involvement, parent monitoring, and parenting confidence. Results. One-third of the children endorsed beliefs that they could smoke without becoming addicted, and 8% to 10% endorsed beliefs on the benefits of smoking. Children's positive attitudes about smoking were associated with lower family cohesiveness (p = .01). Parental use of tobacco was the only significant predictor of children's positive attitudes about tobacco at 20 months (p = .03). CONCLUSIONS: Children as young as 10 years underestimate addictive properties of smoking, which may place them at risk for future smoking. Parental use of tobacco and family cohesiveness are important factors in the formulation of preteen attitudes about smoking.