Time-harmonic magnetic resonance elastography of the normal feline brain.

Imaging of the mechanical properties of in vivo brain tissue could eventually lead to non-invasive diagnosis of hydrocephalus, Alzheimer's disease and other pathologies known to alter the intracranial environment. The purpose of this work is to (1) use time-harmonic magnetic resonance elastography (MRE) to estimate the mechanical property distribution of cerebral tissue in the normal feline brain and (2) compare the recovered properties of grey and white matter. Various in vivo and ex vivo brain tissue property measurement strategies have led to the highly variable results that have been reported in the literature. MR elastography is an imaging technique that can estimate mechanical properties of tissue non-invasively and in vivo. Data was acquired in 14 felines and elastic parameters were estimated using a globo-regional nonlinear image reconstruction algorithm. Results fell within the range of values reported in the literature and showed a mean shear modulus across the subject group of 7-8 kPa with all but one animal falling within 5-15 kPa. White matter was statistically stiffer (p<0.01) than grey matter by about 1 kPa on a per subject basis. To the best of our knowledge, the results reported represent the most extensive set of estimates in the in vivo brain which have been based on MRE acquisition of the three-dimensional displacement field coupled to volumetric shear modulus image reconstruction achieved through nonlinear parameter estimation. However, the inter-subject variation in mean shear modulus indicates the need for further study, including the possibility of applying more advanced models to estimate the relevant tissue mechanical properties from the data.

Imaging characteristics of the subdural evacuating port system, a new bedside therapy for subacute/chronic subdural hematoma.

The Subdural Evacuating Port System is a new device intended to simplify the treatment of subacute/chronic subdural hematomas. The appearance of the winged canula positioned with its tip in the diploic space overlying the subdural space should allow the radiologist to identify it correctly. Its radiographic features are described here to help the radiologist comment on appropriate placement, and avoid mistaking it for a misplaced subdural drain.

Predictors of 30-day hospital readmission after coronary artery bypass.

BACKGROUND: Risk factors for 30-day hospital readmission following coronary artery bypass grafting (CABG) have not been established. METHODS: We prospectively followed 485 consecutive patients who underwent isolated primary CABG at our institution in 1997. Patients were contacted by telephone at 30 days following operation to determine readmission status. RESULTS: The overall readmission rate was 16% (76 of 485). Female gender (25% versus 11%, p = 0.001) and diabetes (22% versus 12%, p = 0.005) were associated with significantly higher readmission rates. The relationship between female gender and readmission persisted after correcting for age and other comorbidities. Congestive heart failure trended towards a significant relationship with increased readmission rate (22% versus 14%, p = 0.09). There were no significant associations between 30-day readmission rate and age, hypertension, chronic obstructive pulmonary disease, history of myocardial infarction, peripheral vascular disease, creatinine level of > or = 1.4 mg/dL, or decreased left ventricular ejection fraction (< 40%). CONCLUSIONS: These data show that most of the classic risk factors for postoperative mortality are not necessarily associated with increased readmission. However, female gender and diabetes are associated with greater than twice the risk of 30-day readmission following CABG.

Surgical resident research in New England.

HYPOTHESIS: This study sought to determine the attitudes of general surgery residents in New England toward research and the factors that affect their research participation and productivity. DESIGN: Survey. SETTING: Eighteen of the 20 general surgery residency programs in New England. PARTICIPANTS: Four hundred fifty-nine surgical residents taking the American Board of Surgery In-Training Examination in 1999. MAIN OUTCOME MEASURES: Rationale for and amount of time spent in research and the number of publications. RESULTS: A majority of residents (61%) participated in research. Rationales for research participation included initiating an academic career (82%) and enhancing fellowship application prospects (83%). Personal debt was substantial, but had little influence on decisions regarding research. Gender was not a factor in the decision to participate in research, although women were more likely to cite a break from residency as a positive influence in their decision for doing research. Residents from larger programs (>25 residents) were more likely to participate in research, spend more time in research, and to publish an article than those from programs with fewer than 25 residents. CONCLUSIONS: Most surgical residents in New England plan to or participate in research and publish their work. Significant differences in the type, duration, and productivity of research exist between larger and smaller programs, and may reflect differing priorities among residents, or differences in the variety of research opportunities available.