Two magnetization transfer (MT) contrast effects, a T2-like effect and the improved contrast observed when gadolinium is used with MT, are combined in a single sequence. Forty patients (22 males:18 females; mean age, 45 years (23-87)) with suspected intracranial pathology underwent MRI on a 1.5 Tesla system. Of 46 lesions; seven were ischemic, five infective, seven neoplastic, four hemorrhagic, four multiple sclerosis, seven human immunodeficiency virus (HIV) leukoencephalopathy, nine normal/miscellaneous, and three gliosis. A conventional spin-echo sequence (TR 900 TE 15) was used with on-resonance binomial MT pulses. The sequence was performed postgadolinium +/- MT. The signal intensity ratios +/- MT were: white matter, 0.62 +/- 0.03; gray matter, 0.75 +/- 0.04; ischemia, edema, and demyelination, 0.75 (0.57-0.86); and gadolinium/methemoglobin, 0.85 (0.81-0.98). Areas which exhibited MT had T2-like contrast and those that did not maintained expected contrast for the given parameters. The result was a combination of T2-like contrast, gadolinium enhancement, and dark cerebrospinal fluid (CSF) providing both increased sensitivity to lesions which exhibited both contrast features and improved delineation of periventricular lesions. Furthermore, the differential signal between T2-like contrast of edema and gadolinium enhancement in neoplastic or infective lesions was maintained.

Adult↗

PubMedDate not supplied

Pulse sequence optimization for T2-weighted MR imaging of the brain.

The authors implemented bipolar velocity compensated pulse techniques for T2-weighted MR imaging of the brain. Signal-to-noise (S/N) and image quality was compared for pulse sequences with standard and optimized RF pulses, low and regular bandwidth versions and cardiac triggering. Images from bipolar velocity compensated sequences allowed better visualization of vessels and basilar cisterns and improved image quality relative to standard sequences without velocity compensation. The implementation of optimized RF pulses with bipolar sequences resulted in further improvement in image quality. Single echo sequences consistently had improved image quality and signal-to-noise relative to the second echo of a double echo sequence. Low bandwidth bipolar sequences with extended sampling period had 30% higher S/N, but at the cost of slight loss in edge definition. The highest image quality was obtained with the bipolar, optimized RF, single echo sequence. Using this technique contiguous high quality image slices could be obtained with velocity compensation. The addition of cardiac triggering to bipolar sequences resulted in slight improvement in image quality, but this difference was marginal and probably rarely necessary for MR imaging of the brain.

Brain↗

PubMedDate not supplied

Selective population inversion in NMR.

Population inversion of a selected region of a spectrum is a concept which has wide application in both NMR spectroscopy and imaging. While inversion of population at any one frequency is a trivial matter, ensuring an accurate inversion over a specified bandwidth, with negligible perturbation of the magnetization outside that bandwidth, is a major problem. However, by using as a driving function a complex radiofrequency (r.f.) pulse with an envelope of the form (sech beta t)1+5i where 1/beta is the temporal width and t is time, we have found that above a critical r.f. power threshold, magnetization is accurately inverted over a very sharply defined bandwidth, while outside that region, magnetization is returned to its initial position, and population is unaffected. Within the broad limits imposed by our equipment, we have also discovered that the phenomenon is independent of the incident r.f. power.

Magnetic Resonance Spectroscopy↗

PubMedDate not supplied

Incident review management: a systemic approach to performance improvements.

Incident reporting has emerged as a cornerstone of sound quality improvement programs. Sentinel events, "a serious and undesirable occurrence involving the loss of life, limb, or function of an individual served" (Joint Commission on Accreditation of Healthcare Organizations, 1996), is a mandated indicator for Joint Commission standards of accreditation for audited healthcare facilities. Properly investigated and documented individual incidents can lead to systemic improvements, which may enhance the quality of client care and the integrity of the healthcare facility. This article proposes a systemic approach to the incident review (IR) process in long-term healthcare facilities. This comprehensive approach incorporates identification, investigation, and management of the IR process from the inception of a problem to the continued follow-up to ensure that improvement plans are effectively implemented.

Communication↗

PubMedDate not supplied

Challenges to effective incident review management: administrative and clinical factors.

Incident review (IR) is a process for achieving a better understanding of problems related to the health and safety of clients and the integrity of healthcare facilities. The IR process ensures that the quality and the performance of care in a facility continue to be maintained and improved over time. Because of the practical realities of administrative and clinical care issues, the process of implementing IR and related interventions is often challenging. This paper examines the IR process and the barriers that affect and impede it.

Documentation↗