Detection and quantification of chronic cerebrovascular disease: comparison of MR imaging, SPECT, and CT

Twenty patients with angiographically proved occlusion of the internal carotid artery (ICA) (19 unilateral, one bilateral) were studied with magnetic resonance (MR) imaging, iodine-123 iodoamphetamine (IMP) single photon emission computed tomography (SPECT), xenon-133 SPECT, and computed tomography (CT). All patients had a history of stroke or prolonged reversible ischemic neurologic deficit for more than 4 weeks. By regions of interest, T1, T2, regional cerebral blood flow (rCBF), and the number and size of the lesions were determined. The data were expressed as interhemispheric ratios (diseased/nondiseased). The highest ratios obtained were for MR imaging (T1, 2.60 +/- 0.42; T2, 1.61 +/- 0.22 [mean +/- standard deviation]) followed by Xe-133 SPECT (0.58 +/- 0.13) and IMP SPECT (0.56 +/- 0.13). Correlation coefficients for MR imaging (1/T1, 1/T2) and IMP SPECT were below .21. The lesion size was greatest on IMP SPECT images, intermediate on MR images, and least on CT scans. However, MR imaging was superior in detection of pathologic areas (detection rates: MR, 100%; IMP SPECT, 91%; CT, 79%). Relaxation times do not correlate with rCBF.     

Benign thymic enlargement in adults after chemotherapy: CT demonstration

Serial computed tomographic (CT) scans of 200 patients with malignant testicular teratomas were reviewed. Of the 200 patients, 120 were treated with chemotherapy for metastatic disease; 80 patients with no evidence of metastases (stage I disease) received no treatment and served as a control group. CT was performed at regular intervals for ongoing follow-up in both groups. Thymic enlargement occurred 3-14 months after initiation of treatment in 14 of the 120 patients (11.6%) who received chemotherapy but in only one patient in the control group. Histologic examination in one patient who received chemotherapy revealed that the thymic enlargement represented true hyperplasia. Thirteen of the 14 patients (93%) with thymic enlargement after chemotherapy were well and disease free on mean follow-up of 45 months, compared with 78% of the group that did not show thymic enlargement after chemotherapy (P less than .02). Rebound thymic hyperplasia in adults after chemotherapy for metastatic testicular teratoma may be a good prognostic feature and should be considered when an anterior mediastinal mass develops after chemotherapy for metastatic malignancy.     

Venous clots: evaluation with MR imaging

In vitro and in vivo studies were performed to determine the proton relaxation and imaging characteristics of static blood and acute and organized clot in canine jugular veins. In vivo, it was found that two inversion recovery sequences using a short inversion time (100 msec) demonstrated better differentiation of signal intensity of intravascular clot from surrounding soft tissues than did standard T1- and T2-weighted sequences. In vitro, quantitative measurements showed marked reduction of both T1 and T2 relaxation time of acute clot compared with stagnant blood. In addition, the T1 relaxation time, and to a lesser extent the T2 relaxation time, shortened as the clot aged, indicating a potential role for magnetic resonance imaging in determining the age of venous thrombi.     

A STUDY OF THE APPROPRIATENESS OF ANTIBIOTIC USE IN THE MEDICAL WARDS OF A TERTIARY TEACHING HOSPITAL IN MALAYSIA

A prospective study was conducted to determine the proportion of patients who received an antibiotic within 12 hours of admission to the medical wards. During the four-week study, 234 patients were admitted to medical wards from casualty; 68 patients (29%) received an antibiotic. The survey indicated that antibiotics were inappropriate in 22–65% of those treated. This study also shows that as many as 67% of patients who received intravenous antibiotics could have been equally well treated with oral preparations.     

Multimorbidity and Evidence Generation

Most people with a chronic disease actually have more than one, a condition known as multimorbidity. Despite this, the evidence base to prevent adverse disease outcomes has taken a disease-specific approach. Drawing on a conference, Improving Guidelines for Multimorbid Patients, the goal of this paper is to identify challenges to the generation of evidence to support the care of people with multimorbidity and to make recommendations for improvement. We identified three broad categories of challenges: 1) challenges to defining and measuring multimorbidity; 2) challenges related to the effects of multimorbidity on study design, implementation and analysis; and 3) challenges inherent in studying heterogeneity of treatment effects in patients with differing comorbid conditions. We propose a set of recommendations for consideration by investigators and others (reviewers, editors, funding agencies, policymaking organizations) involved in the creation of evidence for this common type of person that address each of these challenges. The recommendations reflect a general approach that emphasizes broader inclusion (recruitment and retention) of patients with multimorbidity, coupled with more rigorous efforts to measure comorbidity and comorbidity burden and the influence of multimorbidity on outcomes and the effects of therapy. More rigorous examination of heterogeneity of treatment effects requires careful attention to prioritizing the most important comorbid-related questions, and also requires studies that provide greater statistical power than conventional trials have provided. Relatively modest changes in the orientation of current research along these lines can be helpful in pointing to and partially addressing selected knowledge gaps. However, producing a robust evidence base to support patient-centered decision making in complex individuals with multimorbidity, exposed to many different combinations of potentially interacting factors that can modify the risks and benefits of therapies, is likely to require a clinical research enterprise fundamentally restructured to be more fully integrated with routine clinical practice.     

Polymorphonuclear leukocyte heterogeneity in neonates and adults

We have used a mouse monoclonal antibody (31D8) to determine whether differences in neutrophil (PMN) subpopulations might help explain decreased PMN chemotaxis in neonates compared with that of adults. 31D8 has been shown to bind heterogeneously to adult PMNs. Approximately 80% of the PMNs that strongly bind 31D8 (31D8 "bright") are the same cells that depolarize and migrate chemotactically when stimulated with the chemoattractant N-formyl-methionylleucylphenylalanine, while the 20% that weakly bind 31D8 fail to similarly respond. All neonatal PMNs bound 31D8 heterogeneously. There was a smaller population of 31D8 "bright" cells in neonates at birth (76% +/- 6%, n = 45) compared with that of neonates at three to 15 days of age (82% +/- 5%, n = 10, P less than 0.002) and both were smaller than that of adults (88% +/- 4%, n = 45, P less than 0.001 and P less than 0.001). Neonatal cord PMNs, which traversed a micropore filter in a modified Boyden chemotaxis chamber in the presence of a chemoattractant, had an increased percentage of 31D8 "bright" cells (89% +/- 7%) than did PMNs which remained above the filter (82% +/- 7%, n = 10, P = 0.034). PMN chemotaxis was less in neonates at birth (32.7 +/- 4.5 micron) than at three to six days of age (36.8 +/- 11.3 micron) and both were decreased compared with that of adults (69.1 +/- 12.4 micron, P less than 0.001 and P less than 0.001). These findings indicate that decreased PMN chemotaxis in neonates may be due in part to a smaller PMN subpopulation of highly motile cells.