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Biomedical subjects

B G Haik

Publications and source records attributed to B G Haik.

80 records · Page 5Linked to original sources
PubMedDate not supplied

Intraocular hemorrhage and mimicking lesions: role of gradient-echo and contrast-enhanced MRI.

Intraocular hemorrhage and mimicking lesions on precontrast spin-echo magnetic resonance images were examined with contrast material and/or gradient-echo pulse sequence. Twenty-two melanomas, nine retinoblastomas, four hemorrhages, one metastasis, and one toxocara endophthalmitis were examined. With contrast material, all tumors demonstrated enhancement, whereas hemorrhage did not. Retinoblastomas demonstrated a heterogeneous enhancement pattern. Computed tomography demonstrated corresponding intratumoral calcifications at the areas of no enhancement. Gradient-echo images demonstrated a heterogeneous pattern in the majority of the lesions compared to spin-echo images. However, relatively characteristic small round areas of signal drop-off representing calcification were observed in about half of the retinoblastomas.

Animals↗
PubMedDate not supplied

Chemotherapy for eye cancer.

Chemotherapy has been used to treat a multitude of eye cancers. We attempted to review the role of chemotherapy in the treatment of ocular, adnexal, and orbital malignancies by conducting an extensive search of the medical literature. Unfortunately, the published reports typically contain few patients with limited follow-up, precluding definitive recommendations. For most eye cancers, multicenter trials will offer the potential to gather the numbers of patients required to determine the clinical utility of chemotherapy.

Antineoplastic Agents↗
PubMedDate not supplied

Regression of uveal malignant melanomas following cobalt-60 plaque. Correlates between acoustic spectrum analysis and tumor regression.

Parameters derived from computer analysis of digital radio-frequency (rf) ultrasound scan data of untreated uveal malignant melanomas were examined for correlations with tumor regression following cobalt-60 plaque. Parameters included tumor height, normalized power spectrum and acoustic tissue type (ATT). Acoustic tissue type was based upon discriminant analysis of tumor power spectra, with spectra of tumors of known pathology serving as a model. Results showed ATT to be correlated with tumor regression during the first 18 months following treatment. Tumors with ATT associated with spindle cell malignant melanoma showed over twice the percentage reduction in height as those with ATT associated with mixed/epithelioid melanomas. Pre-treatment height was only weakly correlated with regression. Additionally, significant spectral changes were observed following treatment. Ultrasonic spectrum analysis thus provides a noninvasive tool for classification, prediction and monitoring of tumor response to cobalt-60 plaque.

Cobalt Radioisotopes↗
PubMedDate not supplied

Retinoblastoma: correlation between age at diagnosis and survival.

Life tables analyses were performed from the records of 1147 patients seen between 1958 and 1983 to determine correlation between age at diagnosis and survival from metastatic retinoblastoma. No difference was noted overall in survival from metastatic retinoblastoma for unilateral vs. bilateral, male vs female, or family history vs negative family history. Survival rate of 21 of 40 patients diagnosed after age 7 and receiving no treatment was 96%. Two patients in this group did develop metastasis: one because of late diagnosis and one because treatment was refused. One patient with an "arrested retinoblastoma" showed growth in his third decade, necessitating treatment. Survival was poorest in patients diagnosed between ages two and seven years where mortality was 19% from metastatic retinoblastoma. Patients diagnosed between birth and two years had an intermediate survival of 95%. Because of second nonocular tumors, survival of the patient with unilateral retinoblastoma was significantly better than that of the bilaterally affected child.

Actuarial Analysis↗
PubMedDate not supplied

MR imaging of malignant uveal melanoma: role of pulse sequence and contrast agent.

To determine the most sensitive pulse sequence and to clarify the role of each pulse sequence in the MR diagnosis of uveal malignant melanoma, noncontrast T1- and T2-weighted, and postcontrast T1-weighted, spin-echo images were compared blindly and independently by two experienced observers. Thirty uveal malignant melanomas, preselected by ophthalmoscopy and sonography for size greater than 2 mm, were examined with a 1.5-T superconducting MR unit with an orbital surface coil. Fifteen tumor studies were done after the patient was injected with gadopentetate dimeglumine. Postcontrast T1-weighted images were the most sensitive in detecting melanomas, demonstrating tumors 2 mm in height accurately on axial planes and 1.6 mm in height on combined orthogonal planes. The contrast-to-noise ratio between melanoma and vitreous fluid was greatest on postcontrast T1-weighted images (average, 72.1), followed by noncontrast T1-weighted images (average, 32.9), and then by T2-weighted images (average, -21.2). Postcontrast T1-weighted images also proved useful in differentiating melanomas from subretinal fluid collections when combined with noncontrast images. We conclude that postcontrast T1-weighted images are most helpful in detecting small uveal melanomas and in differentiating melanomas from subretinal fluid collections.

Contrast Media↗
PubMedDate not supplied

Identification of intraocular tumors by specular microscopy.

Five patients with confirmed diagnoses of intraocular tumors and anterior chamber extension were examined with a wide-field specular microscope. Uniquely shaped dark areas seen on the endothelial surface could be readily distinguished from inflammatory cells by their size and shape. These structures were often associated with a surrounding bright reflection similar to that produced by pigment. The cellular morphology provided by specular microscopy offers the potential for differentiating neoplastic from inflammatory processes in the anterior chamber.

Evaluation Studies as Topic↗