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Biomedical subjects

D Gladstone

Publications and source records attributed to D Gladstone.

13 recordsLinked to original sources
PubMed1999

Prostate seed implant quality assessment using MR and CT image fusion.

PURPOSE: After a seed implant of the prostate, computerized tomography (CT) is ideal for determining seed distribution but soft tissue anatomy is frequently not well visualized. Magnetic resonance (MR) images soft tissue anatomy well but seed visualization is problematic. We describe a method of fusing CT and MR images to exploit the advantages of both of these modalities when assessing the quality of a prostate seed implant. METHODS AND MATERIALS: Eleven consecutive prostate seed implant patients were imaged with axial MR and CT scans. MR and CT images were fused in three dimensions using the Pinnacle 3.0 version of the ADAC treatment planning system. The urethra and bladder base were used to "line up" MR and CT image sets during image fusion. Alignment was accomplished using translation and rotation in the three ortho-normal planes. Accuracy of image fusion was evaluated by calculating the maximum deviation in millimeters between the center of the urethra on axial MR versus CT images. Implant quality was determined by comparing dosimetric results to previously set parameters. RESULTS: Image fusion was performed with a high degree of accuracy. When lining up the urethra and base of bladder, the maximum difference in axial position of the urethra between MR and CT averaged 2.5 mm (range 1.3-4.0 mm, SD 0.9 mm). By projecting CT-derived dose distributions over MR images of soft tissue structures, qualitative and quantitative evaluation of implant quality is straightforward. CONCLUSIONS: The image-fusion process we describe provides a sophisticated way of assessing the quality of a prostate seed implant. Commercial software makes the process time-efficient and available to any clinical practice with a high-quality treatment planning system. While we use MR to image soft tissue structures, the process could be used with any imaging modality that is able to visualize the prostatic urethra (e.g., ultrasound).

Brachytherapy↗
PubMed1998

Radiation-associated morbidity in patients undergoing small-field external beam irradiation for prostate cancer.

PURPOSE: To quantify complication rates after small-field external beam irradiation for adenocarcinoma of the prostate in a uniformly treated patient population with long follow-up using a simple tool designed to identify subtle treatment-related side effects; and to identify clinical and technical variables associated with increased morbidity after irradiation. METHODS AND MATERIALS: A total of 441 patients with nonmetastatic adenocarcinoma of the prostate treated at the Joint Center for Radiation Therapy between 1985 and 1989 were eligible for analysis. Gastrointestinal, genitourinary, and sexual function were assessed retrospectively using a patient self-scoring, five-grade toxicity scale. Seven clinical and 15 technical variables were recorded for each patient. The association between the clinical and technical variables and rectal, bladder, and sexual side effects was examined. The 375 patients who received small-field (<12.5 x 12.5-cm) external beam irradiation via a four-field box on a 6-MV (n = 74, or 20% of patients), 8-MV (n = 140, or 37%), or 15-MV (n = 161, or 43%) linear accelerator form the basis for the study. Ninety-one percent of patients received treatment with 1.8-2.0 Gy fractions to a delivered dose of at least 66 Gy. Follow-up was complete through 62 months in living patients, with five (1%) of the entire group lost to follow-up. RESULTS: A total of 137 of 354 evaluable patients (39%) reported rectal complications after treatment; however, 20 patients(6%) had heme-positive stools as their only symptom and 66 (19%) had mild symptoms not requiring treatment. Only 14% of the entire group required intervention. Of 356 patients, 117 (33%) evaluable for bladder complications developed genitourinary changes: In 14 patients (4%) asymptomatic hematuria occurred, 71 (20%) had mild symptoms not requiring treatment, and 32 (9%) required treatment. Of the 171 patients who were potent prior to radiation, 106 (62%) reported impotence after treatment. No statistically significant association was identified between any clinical or technical variables (including machine energy) assessed and complications. CONCLUSIONS: In this retrospective review, treatment-related bowel and bladder side effects were not identified in the majority of patients despite the use of a grading system designed to identify subtle changes. Impotence, however, was common. Although pretreatment clinical characteristics varied among patients, they could not be used to predict the subsequent development of complications. The only treatment-related characteristic that varied in this study was machine energy, which did not correlate with complications.

Adenocarcinoma↗
PubMed1996

Analysis of prostate and seminal vesicle motion: implications for treatment planning.

PURPOSE: To quantify prostate and seminal vesicle positional changes (target motion) between treatment planning and delivery, and to identify the factors contributing to target motion. METHODS AND MATERIALS: Thirty patients with adenocarcinoma of the prostate were prospectively evaluated by analyzing two sequential planning computerized tomography (CT) scans (S1, obtained prior to treatment, and S2, obtained during the fourth week of treatment) for each patient. All anatomical volumes of interest (soft tissue and bony) were reconstructed from transverse CT images and projected onto anterior and lateral beam's-eye view projections. Positional changes between S1 and S2 were eliminated by applying a rigid body translation and rotation. Target motion was then measured by recording the positional change between S1 and S2 at the edges (right, left, superior, inferior). Potential correlation of target motion with bladder volume, rectal volume, and rectal diameter changes were evaluated by linear regression analysis. RESULTS: Neither the prostate nor seminal vesicles remained fixed with respect to bony anatomy between S1 and S2. The distribution of positional changes were generally small (< 0.5 cm), but maximum displacements of 1.5-2.2 cm did occur, particularly in the lateral view. In this study, bladder volume changes between the scans were small and did not correlate with target motion (P = 0.67). Both rectal volume and rectal diameter changes correlated with target motion for both the prostate (p = 0.004 and 0.005, respectively) and seminal vesicles (p < 0.001 and < 0.001, respectively). However, neither the initial rectal volume nor the initial rectal diameter could be used to predict subsequent target motion when evaluated either singly or as part of a multiple regression model. CONCLUSIONS: Target motion occurs during the course of treatment planning and delivery and should be considered when designing conformal radiation fields. Although the target position at the time of planning CT may differ substantially from the mean treatment position, target motion cannot be predicted by evaluating simply measured parameters from a single scan, or double scan sequence.

Adenocarcinoma↗
PubMed1994

Neurodevelopment of children exposed in utero to phenytoin and carbamazepine monotherapy.

OBJECTIVE: To compare pregnancy outcome prospectively after phenytoin and carbamazepine monotherapy with outcome in matched mother-child pairs exposed to nonteratogens to evaluate the relative fetal safety of these drugs. DESIGN: A prospective, controlled, and blinded observational study. PATIENTS: Thirty-six mother-child pairs exposed to carbamazepine monotherapy and 34 pairs exposed to phenytoin monotherapy, all prospectively studied, were compared with mother-child pairs exposed to nonteratogens. The controls were matched for maternal age, time of consultation, obstetric history, and socioeconomic status. MAIN OUTCOME MEASURE: The primary end point of interest was the children's global IQ measured by either the Bayley or the McCarthy scale according to their ages. SETTING: A teratology consultation program and two neurology services in Toronto, Ontario. RESULTS: Children exposed to phenytoin in utero had a mean (+/- SD) global IQ 10 points lower (95% confidence interval, 4.9 to 15.8 points) than their matched controls (113.4 +/- 13.1 and 103.1 +/- 25.1; P = .038). The Reynell language development scores followed a similar trend, with children exposed to phenytoin scoring significantly lower than their controls. Phenytoin-exposed children had a global IQ of 84 or less significantly more often than the control group (P < .01). Children exposed in utero to carbamazepine did not differ from their controls on any of the neurobehavioral tests. CONCLUSIONS: Our study suggests a clinically important negative effect of phenytoin on neurobehavioral development, independent of maternal or environmental factors, causing a substantial number of children to achieve a lower score than expected on cognitive tests. No similar effects could be shown after gestational use of carbamazepine.

Carbamazepine↗
PubMed1994

St. Jude Medical prosthesis in children.

From December 1980 through April 1992, 20 children 2 to 18 years of age underwent valve replacement with the St. Jude Medical prosthesis. Nine children underwent aortic valve replacement, eight underwent mitral valve replacement, and the three children with corrected transposition underwent left-sided tricuspid valve replacement. Of the 20 patients, 17 underwent 23 previous procedures. All but five patients received adequate adult-sized prostheses. There was one hospital death (5%). All hospital survivors received maintenance doses of sodium warfarin. Follow-up was 100% complete with a total of 106 patient-years. There were no late deaths and no thromboembolic or anticoagulant-related bleeding. None of the patients had prosthetic valve endocarditis or a periprosthetic leak. Reoperation was not required in any patient. The great majority of the children (16 of 19) were in New York Heart Association functional class I, two were in class II, and one with complex congenital heart disease was in class III at the time this article was written. This study illustrates the excellent results of cardiac valve replacement with the St. Jude Medical prosthesis in children and confirms the safety of sodium warfarin in this age group.

Adolescent↗
PubMed1994

The St. Jude Medical prosthesis. A thirteen-year experience.

From May 1979 until July 1992, 1184 patients, 2 to 86 years of age (median = 59 years), received 1367 St. Jude Medical prostheses (578 aortic, 440 mitral, 3 tricuspid, and 170 multiple). Overall early mortality was 4% with 2.4%, 4.3%, and 8.2% after aortic, mitral and multiple valve replacement, respectively. Follow-up was 100% complete (4936 patient-years). Actuarial survival at 10 years (including both early and late deaths) was 71% +/- 4.1% after aortic valve replacement, 58.8% +/- 5.1% after mitral valve replacement, and 58.9% +/- 9.6% after multiple valve replacement. Multivariate analysis identified age, previous operations, diabetes mellitus, extent of coronary artery disease, preoperative New York Heart Association class, and additional procedures as independent prognostic factors for overall survival. All patients including 20 children (2 to 18 years of age) received sodium warfarin. The linearized risk per 100 patient-years for all embolic events (major and minor) was 2.4, 4.4, and 5.0 after aortic, mitral, and multiple valve replacement, respectively; when only major events were considered, the linearized risks were 0.33, 1.17, 1.54, respectively. Freedom from major systemic embolism at 10 years was 96% +/- 2% after aortic valve replacement, 88% +/- 4% after mitral valve replacement, and 89% +/- 3% after multiple valve replacement. Five patients had valve thrombosis, four of whom definitely received inadequate anticoagulation therapy. Ninety-seven patients had 107 episodes of anticoagulant-related hemorrhage (2.2/100 patient-years) accounting for 17 late deaths; 14 of the deaths involved an international normalized ratio in excess of 3.5. To reduce the rate of thromboembolism without increasing the rate of anticoagulant-related hemorrhage, we propose that the international normalized ratio should be kept between 2.5 and 3.0. No recorded structural failure or significant hemolysis was found in the absence of periprosthetic leak. This experience encourages us to continue using the St. Jude Medical prosthesis.

Actuarial Analysis↗
PubMed1992

The perception of teratogenic risk of cocaine.

While there has been a substantial increase in recreational use of cocaine by young adults, conclusive evidence for cocaine teratogenicity in humans is lacking, and even those believing the drug is teratogenic agree that the rates are quite small. While counseling pregnant women on their teratogenic risk, it was our impression that there is an unrealistically high perception of reproductive risk of cocaine. We wished to quantify the perception of teratogenic risk of cocaine by the public, physicians, and by pregnant women who were counseled following gestational exposure to the drug. Women taking cocaine during the first trimester of pregnancy (n = 54), controls with post secondary education (n = 30), and physicians (n = 30) were asked, using a visual analogue scale, to quantify the teratogenic risk of cocaine and the tendency to terminate/continue the pregnancy after first trimester exposure; in the case of the "public" and physicians this was a hypothetical question. Both physicians and the controls perceived cocaine to be teratogenic (13.4 +/- 11% risk of major malformations by physicians, and 56.5 +/- 22.8% by the "public"). The controls believed cocaine to be as hazardous as thalidomide (57.2 +/- 25.6% risk for thalidomide). Asked whether they would wish to terminate such pregnancy in their family, most physicians (56%) and the controls (70%) had a greater than 50% tendency to terminate.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1988

The clinical significance of elevated CSF and plasma histamine in cerebral aneurysm surgery utilizing cardiopulmonary bypass with total circulatory arrest.

Recently there has been a renewed interest in the neurosurgical treatment of large cerebral aneurysms and AV malformations utilising cardiopulmonary bypass (CPB) and total circulatory arrest (TCA). However, the differing tolerance limits of coagulation and bleeding, pH control and fluid constraint are difficult to reconcile. Although clinical assessment, electro encephalogram (EEG) and intracranial pressure-monitoring assist in identification of cerebral damage, CPB and TCA inflict their own penalties with resultant uncertainty in post-operative neurological evaluation, and producing difficulties in interpretation and management. Additionally, an unanswered question is, to what extent the known cardiac and cerebral effects of circulating histamine might influence the post-circulatory arrest recovery in these patients, and whether this would further compromise the neurological result. We report our experience of 9 such cases who underwent this procedure, and were able to achieve a satisfactory neurological result in 7 patients with differing lesions. During the operation both CSF (from the open cranium) and blood (from the right internal jugular vein) were sampled at intervals for subsequent plasma histamine estimation. Despite markedly elevated histamine levels during CPB and TCA, this was not associated with an unfavourable neurological outcome. These early findings have given us encouragement to the useful role of CPB and TCA in these complex neurosurgical presentations, and raise interesting questions about the clinical importance of histamine-evoked cerebral ischaemia that has been demonstrated in experimental models.

Adult↗
PubMed1988

Corneo-scleral rim cultures: donor contamination a case of fungal endophthalmitis transmitted by K-Sol stored cornea.

This retrospective study of 549 corneo-scleral rim cultures shows that gentamicin, used in MK and K-Sol medium storage at 4 degrees C, has decreased donor contamination from 43% in whole-globe storage to 13%, but failed to eliminate coagulase negative staphylococci (37%), streptococci (28%) and fungi (28%). Donor-to-host transmitted staphylococcal and streptococcal endophthalmitis have been reported previously. We present the first documented case of donor-to-recipient transmitted fungal endophthalmitis following corneal transplantation using corneas stored in MK or K-Sol solution at 4 degrees C; Candida albicans was isolated. Recommendations are made to assess critically the true incidence of donor fungal contamination and the necessity of adding anti-mycotic agents to preservation medium for 4 degrees C storage. In the absence of ideal antimicrobial cover for corneal preservation solutions, stringent prophylactic measures to reduce contamination and continued monitoring of corneo-scleral rim cultures are warranted, if the poor visual consequences of donor-to-host transmitted endophthalmitis are to be avoided.

Adolescent↗
PubMed1988

Massive pulmonary embolism; the place for embolectomy.

Untreated massive pulmonary embolism is associated with a high mortality. Pulmonary embolectomy has been largely superceded by thrombolytic therapy, but there are cases in which pulmonary embolectomy remains the treatment of choice. We present three case reports and discuss the merits of the various treatments available for massive pulmonary embolism. The primary treatment of massive pulmonary embolism should be thrombolytic therapy, but for patients who are at risk of haemorrhage following surgery, who are in cardiogenic shock despite medical treatment, or fail to improve following cardiac arrest, then pulmonary embolectomy remains the treatment of choice.

Aged↗