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Biomedical subjects

T C Mills

Publications and source records attributed to T C Mills.

6 recordsLinked to original sources
PubMed1987

Partial flip angle MR imaging.

Theoretical analysis predicts that performing magnetic resonance (MR) imaging with partial (less than 90 degrees) flip angles can reduce imaging times two- to fourfold when lesions with elevated T1 values are being examined. This time savings occurs because repetition time (TR) is reduced when imaging is performed with partial flips. Partial flip MR imaging can also improve signal-to-noise ratio (S/N) in fast body imaging. For this study, analytical tools were used to predict image contrast and S/N for short TR, partial flip sequences. Experimental implementation of the short TR, partial flip sequences that analytical work had predicted would be optimal supported the analytical predictions and demonstrated their validity. Partial flip MR imaging is applicable to reducing imaging time only when the ratio of signal differences to noise exceeds threshold values in conventional MR images. Partial flip sequences can be used to advantage in MR imaging of both the head and the body, and the observed effects are predictable through theoretical analysis.

Brain↗
PubMed1987

Hemorrhagic and nonhemorrhagic brain lesions: evaluation with 0.35-T fast MR imaging.

Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.

Adolescent↗
PubMedDate not supplied

Clinical choices for circulatory assist devices.

Approximately 1.0% of open heart surgery patients become unweanable from cardiac bypass during the surgical procedure. In addition, nearly 20% of patients accepted for cardiac transplantation die while waiting for a donor heart. Pulsatile pneumatic ventricular assist devices (VADs) provide a realistic solution to these dilemmas. Currently, there are five manufacturers who are competing for the major market share in the clinical use of these devices. Novacor, Thermetics, Thoratec, Symbion, and Abiomed all have competitive VAD systems. Because no one system is optimal for all patients, the limitations, similarities, and strengths of each system should be known to enhance the patient's outcome when using these devices. Successful use of VAD systems, either as a bridge to transplantation or to ventricular recovery, is best approached by adherence to strict patient selection. Once instituted, VAD management centers on detailed attention to anticoagulation and prompt diagnosis and treatment of various complications.

Blood Loss, Surgical↗
PubMedDate not supplied

ECMO assisted angioplasty for cardiomyopathy patients with unstable angina.

Patients who are otherwise unsuitable candidates for coronary bypass surgery or standard coronary angioplasty (PTCA) may be successfully treated with PTCA during ECMO. Five patients (3 men, 2 women), with a mean age of 57 years, are reported on here. They were not considered good candidates for standard therapy because of poor left ventricular function (mean EF, 24; range, 16 to 28%). Patients were supported by percutaneous femoral bypass using a BARD CPS machine, and underwent successful PTCA of either two vessels (three patients) or three vessels (two patients); in addition, one patient had dilatation of a stenotic aortic valve. Patients were supported with ECMO for 26 to 140 (mean 104) minutes, and required transfusion with 0 to 4 (mean 2) units of blood during or after the procedure. Complications included groin hematoma in two patients. All were discharged within 4 days of the procedure. Follow-up of the patients has been completed (4-7 mo) with no further hospitalizations for unstable angina. All patients remain in NYHA Class II or III. These data suggest that ECMO-assisted angioplasty is a safe and effective method of palliation of unstable angina associated with cardiomyopathy.

Adult↗