Biomedical subjects

D I Thickman

Publications and source records attributed to D I Thickman.

6 recordsLinked to original sources

PubMed1987

MR evaluation of uterine anomalies.

The MR features of uterine anomalies were analyzed in eight women. Scans were done on a 1.5-T magnet with T1-weighted (TR 600 msec, TE 25 msec) and T2-weighted (TR 2000-2500 msec, TE 35-80 msec) spin-echo images obtained in several planes. The anomalies consisted of bicornuate uterus (three cases), septate uterus (one case), bicornuate uterus with septation (two cases), unicornuate uterus (one case), and uterus didelphys with vaginal septum (one case). These diagnoses were confirmed by hysterosalpingography with laparoscopy (five cases), dilation and curettage with laparoscopy (one case), or cesarean section (two cases). In six of the eight cases, MR correctly identified and accurately classified the type of anomaly. In the other two cases, the MR diagnosis was a bicornuate uterus with septation. One case proved to be a uterus didelphys with vaginal septum, and the other a bicornuate uterus without septation. The study shows that MR is a valuable tool for the diagnosis of uterine anomalies.

Female↗

PubMed1983

Nuclear magnetic resonance characteristics of fresh and fixed tissue: the effect of elapsed time.

The nuclear magnetic resonance relaxation times T1 and T2 of liver and spleen from freshly euthanized rats were measured over 48 hours for samples treated with normal saline, fixed with 70% ethanol, neutral buffered formalin, or 10% formalin, or left untreated. The initial values of T1 and T2 for both tissues agreed with previous determinations. For untreated tissues of both liver and spleen, T1 was stable for 6 hours and T2 was stable for 48 hours. For fixed tissues, T1 was stable for 0.5 hours, but T2 changed in 0.5 hours.

Animals↗

PubMed1983

Effect of display format on detectability.

The effects of black-echo (black dots on white background) and white-echo (white dots on black background) display formats on detectability of a wire embedded in an echogenic test object were compared. Trained observers were asked to note the presence or absence of the wire on a randomized series of 528 B scans (264 black-echo and 264 white-echo images), half of which contained a wire. The scans not containing a wire were used as controls. The specificity of the white-echo display (75 per cent) exceeded that of the black-echo display (54 per cent), with statistical significance at the 99 per cent confidence level. There was no measurable difference in sensitivity. These results are explained in terms of principles of visual physiology.

Ultrasonography↗

PubMed1983

Clinical manifestations of the comet tail artifact.

The comet tail artifact appears as a dense tapering trail of echoes just distal to a strongly reflecting structure. This reverberation type of artifact occurs when there is a marked difference in acoustic impedances between an object and its surround. This paper presents a spectrum of comet tail artifacts seen in clinical practice and discusses their usefulness in decision making.

Foreign Bodies↗

PubMedDate not supplied

MR imaging of fetal brain.

Magnetic resonance (MR) imaging was used to evaluate normal fetal intracranial anatomy in axial, coronal, and sagittal planes. The T1 and T2 weighted images (WI) of aborted fetuses of varying gestational ages were correlated with anatomic sections. In the premature fetus three distinct intensity zones were seen on MR that were not visualized on gross specimens. Unmyelinated white matter displays low intensity on T1 W1 and high intensity on T2 W1. Maturational changes of the brain were observed with advancing fetal age.

Brain↗

PubMedDate not supplied

The comet tail artifact.

A description and explanation of an unexpected echographic appearance in a patient who had sustained an abdominal shotgun wound is presented. In the B-scans, a trail of dense continuous echoes, simulating a comet tail, is seen distal to each lead pellet. This comet tail appearance is shown to be a type of reverberation artifact. The effect of object size, shape, composition, and orientation on the appearance of this artifact is demonstrated.

Animals↗