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Biomedical subjects

D K Li

Publications and source records attributed to D K Li.

At least 91 records · Page 5Linked to original sources
PubMed1986

Pseudo perisplenic "fluid collections": a clue to normal liver and spleen echogenic texture.

In a number of cases the ultrasound examination of the left upper quadrant showed an appearance suggesting a fluid collection around the superior and lateral aspects of the spleen. Subsequent investigations including careful real-time evaluation, computed tomography, and magnetic resonance imaging have demonstrated that the pseudo-"fluid collection" is the normal left lobe of the liver extending into the left subdiaphragmatic space to lie superior and even lateral to the spleen. The echogenicity of the normal liver was observed to be less than that of the normal spleen. The ability to simultaneously visualize both the liver and the normal spleen at the same depth and the same field of view gives a true indication of the relative echogenic consistency of the liver and the spleen, which is different from that which had been previously reported.

Adult↗
PubMed1986

Magnetic resonance imaging of the ligaments and menisci of the knee.

Although the technique is still developing and the data are preliminary, MRI will likely be the best noninvasive method for evaluating the ligaments and menisci of the knee. It can provide valuable and accurate information, especially in the acutely injured knee. The presence, extent, and exact location of cruciate ligament disruption can be visualized. This is useful in patients in whom the clinical diagnosis is uncertain and provides valuable information in preoperative planning. Equally important is the ability of MRI to provide diagnostic information about associated injuries to the collateral ligaments, capsule, menisci, articular cartilage, and subchondral bone. Proper pulse sequence selection is important. T2-weighted spin-echo sequences are best for visualizing injuries to the ligaments and menisci, and T1-weighted sequences (inversion-recovery or spin-echo with a short TR and a short TE) are more helpful in evaluating cartilaginous and bony abnormalities.

Arthroscopy↗
PubMed1985

Magnetic resonance imaging of aneurysms of the abdominal aorta.

Experience with magnetic resonance imaging (MRI) of 10 normal control patients and 13 patients with known abdominal aortic aneurysms is presented. The aorta, renal artery origins, and iliac arteries were clearly identified in all control patients. Ten out of 13 aneurysms were optimally visualized. Three cases early in the experience were poorly seen and permitted less confident measurements. Renal artery origins were identified in 12 cases and judged to be uninvolved by the aneurysm in 11. Iliac arteries were identified in 11 cases and judged to be definitely aneurysmal in three. Sonography clearly depicted all 13 aneurysms. Correlation of the actual anteroposterior (AP) and transverse diameter aneurysm measurements with both techniques was excellent. Sonography failed to identify the renal artery origins in all cases, but could infer noninvolvement in two cases. Iliac arteries were seen in eight cases and judged definitely aneurysmal in three. According to these preliminary results, both MRI and sonography provide accurate AP and transverse outer wall measurements. MRI is superior in determining the presence of renal and/or iliac involvement. The authors recommend, however, that sonography continue to be the preliminary screening method.

Aorta, Abdominal↗
PubMed1985

Pitfalls to avoid: the right paraspinal pseudotumor.

Fat in the fissure for the ligamentum teres, if abundant and sagittally oriented, will outline the right margin of the lateral segment of the left lobe of liver. This produces the appearance of a right paraspinal mass on plain abdominal radiographs. The nature of the anatomical relationships has been demonstrated using computed tomography.

Adipose Tissue↗
PubMed1984

Ultrasonic refraction by the rectus abdominis muscles: the double image artifact.

Using a real-time mechanical sector scanner in a transverse plane of section, the authors noticed that a double image of an intrauterine gestational sac or an intrauterine contraceptive device can be obtained when the transducer is passed over the midline of the abdomen. It was suggested that this is caused by refraction of the sound passing through the medial edges of both rectus abdominis muscles. The authors were able to reproduce this artifact in vitro using isolated human cadaver rectus muscles and imaging a single object in a water bath.

Abdominal Muscles↗
PubMed1982

Sonographic demonstration of air-fluid levels in abdominal abscesses.

Abdominal sonograms were obtained for three patients who had clinically suspected abscesses. There were abnormal fluid collections that, when viewed from a posterior position, demonstrated a horizontal line representing an air-fluid level. Abdominal abscesses containing air were confirmed by both horizontal beam radiography and surgery. Since ultrasound examination is frequently performed before radiography in patients thought to have abscesses, it is important to look for and recognize the sonographic appearance of an air-fluid level.

Abdomen↗
PubMed1981

Abdominal computed tomography in Whipple's disease.

The computed tomographic findings in a patient with Whipple's disease are described. Particular emphasis is placed on the extraintestinal manifestations of lymphadenopathy, which are not as familiar to radiologists and have been difficult to demonstrate with conventional radiographic techniques.

Adult↗
PubMed1980

Needle orientation for transhepatic cholangiography: CT localization of the porta hepatis.

The needle orientation recommended for transhepatic cholangiography has a consensus in the literature for the sagittal and the transverse planes. Because of differing recommendations for the needle orientation in the coronal plane, the location of the porta hepatis was analyzed in 50 patients undergoing computed tomography. The mean ratio between skin to the porta hepatis distance and AP patient diameter is 0.38. The best puncture site therefore lies anteriorly to the halfway mark at the midaxillary line by about 3 cm.

Cholangiography↗
PubMed1979

Krypton-81m: a better radiopharmaceutical for assessment of regional lung function in children.

Krypton-81m, an inert, radioactive gas with a physical half-life of 13 seconds was used to evaluate regional lung ventilation in 25 pediatric patients. The results suggest that Kr-81m has several advantages over previous methods employing xenon-133. These include: more favorable physical characteristics for imaging with present scintillation cameras; ease of performance of the examinations; improved resolution and multiple views with better detection and localization of abnormalities; and a much lower dose to the patient.

Adolescent↗
PubMedDate not supplied

MR imaging artifacts produced by dental materials.

This report evaluates a variety of dental materials with respect to MR imaging artifacts and their mechanisms of production. A 0.15-T superconducting system and an MR phantom were used in assessing imaging artifacts. Several in-vivo studies were also carried out. The dental materials were analyzed for composition and magnetic permeability and the results were compared with the artifacts produced by each material. It was found that the higher the magnetic permeability the greater the artifact produced. Magnetic permeability of a material is generally not predictable on the basis of its composition, however.

Dental Materials↗