Determination of bone mineral density by dual x-ray absorptiometry in patients with uncemented total hip arthroplasty.

Bone remodeling is an expected sequela with total hip arthroplasty (THA). Although there are several methods of estimating bone response in THA patients from radiographs, there are no accurate and generally accepted methods for quantitative determinations in vivo. In this study, we describe an application of dual x-ray absorptiometry (DXA) for measuring bone mineral content and bone mineral density in the proximal femur following THA. DXA is a noninvasive technique with minimal radiation exposure (< 5 mrem). Various aspects of measurement error (accuracy and reliability) of this application of DXA were determined in a series of studies reported here. Accuracy error (how similar are the measured and actual values) was < 1% determined in bone phantoms of four densities. Precision error (how reproducible are the measurements) was also < 1% at all four densities in the phantoms and was only slightly elevated (0.9-1.5%) in repeated measurements of implanted cadaver femora. Precision error in vivo, determined both from multiple replicates on five patients and from duplicate scans on 30 patients, was further elevated but remained < 5%. Contributions to precision error, rotation of the leg, and interoperator variability were assessed; none was found to elevate precision error appreciably. We suggest that DXA is a feasible method for quantifying bone response following THA, and will allow discrimination of small changes (> 5%) not previously measurable.     

Monosomy 7 mosaicism in metastatic choroidal melanoma

Uveal melanoma is the most common primary intraocular malignancy in adults. Several cytogenetic studies on uveal melanoma cells have revealed that the majority of these cells harbor alterations in chromosomes 3, 6, and 8. This report describes the results of cytogenetic analysis performed on a fresh choroidal melanoma tissue sample from a patient with cerebellar metastasis. Monosomy 7 mosaicism was observed. To our knowledge, monosomy 7 has not been reported in patients with uveal melanoma. We suggest that observation of monosomy 7 may be related to an aggressive clinical behavior and unusual cerebellar metastasis in uveal melanoma. Further data are necessary to define the exact role of monosomy 7 in the pathogenesis and evolution of uveal melanoma.     

Bilateral papillomacular retinal folds and posterior microphthalmus: new features of a recently established disease

Clinical findings of a 2.5-year-old girl presenting with barely detectable horizontal nystagmus and high hypermetropia are described. Despite the normal appearing anterior segments, the child had posterior microphthalmus and bilateral papillomacular retinal folds, conforming to a recently described, rare congenital disease. The patient also had significant posterior pole excyclorotation and avascular zones at the extreme temporal periphery without ridge formation or neovascularization. These findings were not reported previously. Other remarkable features include mildly depressed photopic and scotopic electroretinogram amplitudes and a short axial length of the vitreous cavity compared to age-matched normals, measured by ultrasonography. The present case adds new elements to this relatively rare ocular developmental abnormality.     

Retinitis pigmentosa associated with peripheral sea fan neovascularization

PURPOSE: To describe a case with retinitis pigmentosa associated with sea fan type retinal neovascularization. METHODS: Complete ocular examination including fluorescein angiography was performed in a 9-year-old girl. RESULTS: Ophthalmoscopically, in addition to arteriolar narrowing and bone corpuscular pigmentation of both retinae, a vascular lesion with surrounding intraretinal exudation was noted in the upper equatorial region of the right eye. On fluorescein angiography, the lesion stained in the form of a sea fan neovascularization. CONCLUSION: Sea fan type of neovascularization can be seen in association with retinitis pigmentosa. Fluorescein angiography is important in identifying the exact nature of such a lesion.     

Subretinal pigment dispersion following transpupillary thermotherapy for choroidal melanoma

PURPOSE: To report the case of a patient who developed considerable subretinal pigment/debris dispersion following transpupillary thermotherapy (TTT). This type of tumour response is extremely rare with this relatively new therapeutic modality. METHODS: A 50-year-old man with a left juxtapapillary choroidal melanoma measuring 8 x 6 x 4.3 mm was treated with 810 nm diode laser TTT administered in two sessions. Spot size was 3 mm and the power setting was 450 mW. RESULTS: Four months after the first treatment session, a considerable amount of pigment/debris was seen to have dispersed in the subretinal space, accumulating mainly in the macular area. Over a 12-month follow-up, the tumour showed progressive shrinkage without any change in the amount or location of the shed pigment/debris. No new tumour formation, recurrence or systemic metastases were detected. CONCLUSION: Subretinal pigment/debris dispersion is an unusual complication after TTT and requires close follow-up. There has been no short-term compromise on the life or visual acuity of this patient.     

Persistent intraschisis hemorrhage simulating choroidal melanoma

BACKGROUND: Intraschisis hemorrhage of dark green color without accompanying vitreous hemorrhage is a rare complication of degenerative retinoschisis-detachment. CASE: A 37-year-old male patient with unilateral intraschisis hemorrhage closely mimicking a choroidal melanoma is described. OBSERVATIONS: Ultrasonography and intravenous fluorescein angiography suggested intraschisis hemorrhage. T(1)-weighted magnetic resonance imaging demonstrated a hyperintense lesion compared to the vitreous that did not enhance with contrast agent. Managed by observation, the color of the lesion started to change at the 6th month of follow-up. The hemorrhagic lesion regressed to half size in 40 months following the diagnosis, and disappeared in 62 months. CONCLUSION: Very rarely may an intraschisis hemorrhage secondary to degenerative retinoschisis-detachment simulate a choroidal melanoma. In our patient, careful interpretation of the conventional methods was adequate for the differential diagnosis. The unusual feature of this patient was that the hemorrhage resolved in 5 years, much slower than expected.     

Role of scintigraphy in congenital thyroid anomalies

Thyroid scintigraphy using Tc-99m pertechnetate is a frequently performed procedure in routine nuclear medicine practice. The indications for thyroid scintigraphy are investigation of hyperthyroidism, nodularity of the gland, cause of thyroid stimulating hormone elevation and localization of an ectopic thyroid gland. In the pediatric population, the most common request is for the evaluation of neonatal hypothyroidism. This imaging procedure is helpful in the identification of the underlying cause as well as in making a differential diagnosis. Early diagnosis is essential for appropriate therapy planning in this age group, and thyroid scintigraphy provides important diagnostic data. This article is written to review the scintigraphic findings in various congenital thyroid anomalies and to underline its use in the differential diagnosis.