PubMed Health⌕ Search

Biomedical subjects

P Rothschild

Publications and source records attributed to P Rothschild.

9 recordsLinked to original sources
PubMed1989

Accessible magnetic resonance imaging.

The cost of magnetic resonance imaging (MRI) is driven by magnetic field strength. Misperceptions as to the impact of field strength on performance have led to systems that are more expensive than they need to be. Careful analysis of all the factors that affect diagnostic quality lead to the conclusion that field strength per se is not a strong determinant of system performance. Freed from the constraints imposed by high-field operation, it is possible to exploit a varied set of opportunities afforded by low-field operation. In addition to lower costs and easier siting, we can take advantage of shortened T1 times, higher contrast, reduced sensitivity to motion, and reduced radiofrequency power deposition. These conceptual advantages can be made to coalesce onto practical imaging systems. We describe a low-cost MRI system that utilizes a permanent magnet of open design. Careful optimization of receiving antennas and acquisition sequences permit performance levels consistent with those needed for an effective diagnostic unit. Ancillary advantages include easy access to the patient, reduced claustrophobia, quiet and comfortable operation, and absence of a missile effect. The system can be sited in 350 sq ft and consumes a modest amount of electricity. MRI equipment of this kind can widen the population base than can access this powerful and beneficial diagnostic modality.

Costs and Cost Analysis↗
PubMed1989

[New possibilities and aspects of low-field magnetic resonance tomography].

Worldwide, MRI is going up to higher field-strength. For imaging, magnets with field-strength between 0.2 and about 2.5 Tesla are installed. Below 0.2 Tesla, Low-Field-systems have been used in research-projects to optimize image quality. New developments of 0.064 Tesla Permanent-Magnet-MRI are hopeful for clinical work. Future possibilities of Low-Field-MRI are shown. The advantages of this system are good image quality by low initial start-up and operating costs as well as ease of sitting and lack of need for cryogens. The open design has excellent patient acceptance and allows to examine patients with claustrophobia feelings. It allows easier monitoring during the examination-especially children and patients with cancer or polytraumatic diseases. The introduction of more affordable MRI-systems of low-field-strength may decrease the cost of MRI to the point where it is competitive with computer tomography.

Costs and Cost Analysis↗
PubMed1988

Ultrasound breast examination of asymptomatic patients with normal but radiodense mammograms.

Of 1757 consecutive women patients examined with ultrasound (US) between 1983-1986, 796 patients were asymptomatic, had no masses on their mammograms, and were scanned with whole breast US because their breasts were radiodense on mammography. Combinations of automated and real-time hand-held equipment, ranging in frequency from 3.9 MHz to 10 MHz. were used. Of the 796 examinations, 71.5%(569) were normal, 23.5%(187) disclosed cysts, and 4.3%(40) revealed solid masses. Four masses were biopsied, yielding one malignancy, two fibroadenomas and one normal breast tissue. All but 4 of the remaining 36 asymptomatic women with solid masses had a follow-up period of at least 1 year. In the authors' opinion, this low yield of one breast cancer in 796 asymptomatic women implies that whole breast US is of little value (in terms of breast cancer detection) in breasts that are radiodense but otherwise negative on mammography.

Adolescent↗
PubMedDate not supplied

Film-screen mammography x-ray tube anodes: molybdenum versus tungsten.

Gridless screen-film mammography at 23 kVp with a W anode (inherent filtration: 0.1 mm A1, added filtration: 0.025 mm Mo) can achieve contrast identical to that achieved with gridless film-screen mammography at 27 kVp with a Mo anode (inherent filtration: 1.0 mm Be, added filtration: 0.025-mm Mo). However, W-anode film-screen mammograms obtained at 23 kVp require more radiation than Mo-anode film-screen mammograms obtained at 27 kVp. The lack of contrast of W-anode film-screen images produced at the same kVp as Mo-anode images was verified clinically and with a low contrast test object imaged over a range of densities. A step wedge test object was then used to match contrast between Mo- and W-anode gridless film-screen images at various kVp. The low contrast test object images verified the contrast equivalence of images obtained at 23 kVp for a W anode and 27 kVp for a Mo anode. A comparison of the two kVp for different anode materials was tested clinically on ten patients. The clinical and low contrast test object experiments were reviewed by three radiologists specializing in mammography.

Electrodes↗