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Biomedical subjects

L C Chiu

Publications and source records attributed to L C Chiu.

At least 19 recordsLinked to original sources
PubMed1992

Multiplanar gradient recalled images of the knee: comparison of different flip angles and echo times.

To determine the most appropriate combination of echo time (TE) and flip angle in gradient echo images of the knee, the authors used different TEs (10, 20 and 30 msec) and flip angles (10, 30, 50, 70, 90, 120 and 150 degrees) to perform a systematic study of MRI on 10 volunteer knees. Contrast-to-noise ratios of cartilage-fat, fluid-cartilage, fluid-fat and fluid-ligament were calculated and compared. Images with a 30-degree flip angle combined with 20 msec of TE were found to have the best contrast-to-noise ratios in both objective data analysis and subjective observation. Hyaline cartilage of the knee was hyperintense and was well delineated on this pulse sequence, appearing distinct in contrast to the intra-articular fluid. It is concluded that this T2-weighted gradient echo pulse sequence is an alternative to conventional spin echo T2-weighted imaging of the knee.

Echo-Planar Imaging↗
PubMed1989

Nuclear magnetic resonance study of obsessive-compulsive disorder.

Magnetic resonance imaging (MRI) of the brains of 32 patients who met the DSM-III criteria for obsessive-compulsive disorder and of 14 normal subjects frequently revealed abnormalities, but none was specific to obsessive-compulsive disorder. Spin-lattice relaxation time (T1) for right frontal white matter was prolonged in the patients compared to the control subjects, and the patients had greater right-minus-left T1 differences for frontal white matter. Right-minus-left T1 differences in the orbital frontal cortex were strongly correlated with symptom severity in the unmedicated patients and in the patients with family histories of obsessive-compulsive disorder.

Adult↗
PubMed1989

Pott's disease. A resurgent challenge to the thoracic surgeon.

Nineteen patients were treated at the Los Angeles County Harbor/UCLA Medical Center between 1971 and 1986 for tuberculosis of the spine. Fourteen were immigrants, a high-risk group. A high index of suspicion is required for Pott's disease, which occurs in fewer than 1 percent of patients with tuberculosis, often presents with nonspecific symptoms, and may result in permanent deformity or neurologic impairment. CT scan, the most useful diagnostic test, showed abnormal results in 11 of 11 patients. MRI, a newer modality, may provide even more information. Eight patients required operation in addition to antimicrobial therapy. Four had lesions between T3 and T10, where the spinal canal is narrow, of whom three (75 percent had neurologic involvement. All four underwent anterior approach (thoracotomy) for decompression, debridement, and spinal fusion. Fifteen had lesions between T11 and S2. Three (20 percent) had neurologic involvement but responded to medical treatment alone. Four underwent drainage of abscess or spinal fusion for deformity. Combined surgical and medical treatment gave excellent results in this series.

Adolescent↗
PubMed1987

Superior vena cava obstruction: a venographic classification.

Analysis of venacavograms in 27 patients with superior vena caval obstruction revealed the following four patterns of venous collateral return: type I, partial obstruction (up to 90% stenosis) of the superior vena cava with patency of the azygos vein; type II, near-complete to complete obstruction (90-100%) of the superior vena cava with patency and antegrade flow through the azygos vein and into the right atrium; type III, near-complete to complete obstruction (90-100%) of the superior vena cava with reversal of azygos blood flow; type IV, complete obstruction of the superior vena cava and one or more of the major caval tributaries, including the azygos system. These patterns correlate well with the patients' clinical courses and can be used to identify patients who are at risk of developing cerebral and airway compromise and therefore would benefit from superior vena cava bypass surgery.

Adult↗
PubMed1978

Comparison of radionuclide and computed tomography scanning in non-neoplastic intracranial disease.

In this comparison of computed tomography (CT) and radionuclide scanning (RN) in non-neoplastic disease, the CT and RN patterns in vascular occlusive disease, vascular anomalies, cerebral hemorrhage, cerebral infections, and trauma are described in detail. A retrospective evaluation of CT and RN findings in 514 patients provides a basis for determining which modality is more sensitive in a given disease entity. Illustrative cases demonstrate pertinent findings in both CT and RN scanning in the aforementioned disease categories.

Brain↗
PubMed1978

Computed tomography of the pelvis.

The computed tomography scan has revealed the location and size of abnormal pelvic masses as an adjunct to other diagnostic studies. We have extended its usefulness by air distension of the bladder, which accommodates to adjacent structures and, therby, highlights abnormalities in its own wall and in other organs. The patients are prepared according to a simple routine. As we attempt further economy and efficiency the cost of each study becomes justified by the information gained.

Adenocarcinoma↗