FLAIR and magnetization transfer imaging of patients with post-treatment Lyme disease syndrome.

OBJECTIVE: To determine patterns of abnormalities on cerebral MRI that may characterize subgroups of patients with post-treatment Lyme disease syndrome (PTLDS) and to help identify pathomechanisms of disease. METHODS: The authors analyzed the distribution of cerebral lesions in a cohort of 27 patients with PTLDS. A subgroup of eight patients with PTLDS was further studied using whole-brain magnetization transfer ratio measures to identify abnormalities not seen on T2-weighted images. RESULTS: Four patients had focal neurologic deficits, relapsing-remitting disease, and lesions in a distribution typical of MS. Twenty-three patients presented with nonfocal symptoms such as fatigue, subjective memory deficits, and mood disturbance. Twelve of these patients had normal MRI, including the more sensitive fluid-attenuated inversion recovery sequence, 10 had primarily punctate and subcortical lesions, and one patient had multiple periventricular lesions. CONCLUSIONS: In a portion of patients with post-treatment Lyme disease syndrome, white-matter hyperintensities tend to occur in subcortical arteriolar watershed areas and are not specific. Magnetization transfer ratio analysis did not provide evidence for structural abnormalities of the brain parenchyma in patients with nonfocal disease.

Ultrasonic characteristics of retinopathy of prematurity presenting with leukokoria.

The B-mode ultrasonic appearance of eyes afflicted with retinopathy of prematurity exhibiting leukokoria was retrospectively investigated as an aid to increase the accuracy in assessing the patient with leukokoria. B-mode sonograms were obtained employing the immersion technique (Sonometrics 150 A/B-mode instrument). Contact A-mode confirmation was made (Kretztechnik 7200 MA instrument). Prominent B-mode characteristics included echo patterns consistent with increased corneal thickness (47%), shallow anterior chamber depth (73%), malpositioned lens (64%), cataractous lens changes (64%), fibroproliferation in the anterior vitreous (63%), total retinal detachment (53%), partial retinal detachment and/or retinal fold (30%), choroidal thickening (30%), and acoustic shadowing of orbital fat (33%). Together, these features aid in the ultrasonic differentiation from other causes of leukokoria.

Five-year follow-up of helium ion therapy for uveal melanoma.

One hundred sixty-four patients with uveal melanoma were treated with helium ion irradiation prior to May 1984, and the data were analyzed in June 1989. Most uveal melanomas were large, with a mean tumor thickness of 6.5 mm; approximately 60% of the patients had tumors that extended anterior to the equator. A complete follow-up was obtained for all patients. One hundred twelve patients were alive at the time of this report; 18% of the patients developed clinical and laboratory evidence of metastases and eventually died of widespread tumor. Eighty-four percent of eyes were retained. Data were analyzed with a number of parametric and nonparametric techniques. Larger tumors and those located in close proximity to the optic nerve and fovea had a higher incidence of most complications, especially visual loss.

An ultrasonographic study of the persistence of buckle height three years after segmental sponge explants.

We studied a consecutive series of rhegmatogenous retinal detachments treated with segmental silicone sponge explants and cryotherapy, with or without drainage, approximately three years postoperatively by ultrasonography to determine the degree and persistence of the height of the buckle measuring 1.5 to 3 mm remained in all patienst examined clinically and ultrasonographically at three years or later. Five of these patients reexamined one year later demonstrated no loss of buckle height between the third and fourth postoperative years. By comparison, in a small group of patients examined early in their postoperative course (2.5 to 4 months), the buckles were only slightly higher than in the group studied at three years. Buckle height thus appeared to stabilize relatively quickly postoperatively and to persist at least three years. We believe encapsulation of the sponge by scar tissue must contribute to the long-term maintenance of buckle height.

Pupillary membrane excision and anterior vitrectomy in eyes after uveitis.

Three patients with uveitis and dense pupillary membranes, total synechial closure of the angle, and low or normal pressure, underwent membranectomy and anterior vitrectomy via a limbal approach using scissors and a vitrectomy instrument. Postoperatively all regained useful vision that has been maintained for over two years despite the persistence of angle closure in all cases and severe hypotony in two.

Monocular axial myopia associated with neonatal eyelid closure in human infants.

We studied eight infants who developed unilateral axial myopia associated with neonatal eyelid closure. Clinical findings and ultrasonographic biometric measurements suggested that axial elongation of the eye may occur as a result of neonatal eyelid closure, a finding similar to that for experimental myopia produced in neonatal animals after eyelid fusion. Early treatment of eyelid occlusion in the neonate may prevent axial myopia and subsequent anisometropic amblyopia.

Glaucomatous cupping of the optic disk by ultrasonography.

B-scan ultrasonography was used to evaluate advance glaucomatous cupping of the optic disk (0.7 cup/disk ratio or greater) in one normal subject and six patients with glaucoma. The normal eye emitted a continuous echo from the posterior pole, which conformed to its mild degree of concavity. The glaucomatous eyes emitted echos from the posterior pole, demonstrating the more extreme concavity of the optic cup. Ultrasonographic evaluation of an acrylic plate containing holes of known diameter demonstrated the limits of resolution and artifacts that resulted from this examination.

Uveal melanoma necrosis after helium ion therapy.

A 71-year-old man underwent enucleation because of intractable pain ten months after receiving helium ion therapy for a uveal melanoma. There was no clinical or ultrasonographic evidence of tumor regression but histologically the tumor appeared almost entirely necrotic.

Diagnostic modalities in choroidal melanoma.

We prospectively studied 51 patients with choroidal melanomas in a masked manner to determine the accuracy of clinical, ultrasound, and fluorescein diagnosis as well as the accuracy of tumor size measurements. In patients with clear media, clinical diagnosis was the most accurate means of detecting a choroidal melanoma. There was excellent correlation between clinical, ultrasound, and pathology measurements of tumor size. In small melanomas, clinical examination was the most accurate means of measuring tumor diameter and ultrasound the most accurate method of measuring tumor height. Even with a trained ocular oncologist, there was a significant variability in tumor measurements on serial ophthalmoscopic examinations.

Correlation of visual field, treatment fields, and dose in helium ion irradiation of uveal melanoma.

We correlated predicted radiation distributions in 29 patients with uveal melanoma (treated with 5,000 to 8,000 rads of helium ion therapy) with fundus photography and visual field deficits. The tumor was entirely within the treatment region in all patients. The fraction of the predicted high-dose and low-dose regions corresponding with an absolute scotoma was fitted by a linear regression model (r2 = .721) with three independent variables: dose region, initial condition, and time since therapy. The defect in the maximum-dose region increased at an average rate of 0.270/year. This differed (P = .002) from the rate in the penumbra region: (0.104/year). The rate in the penumbra differed (P = .01) from that in the predicted low-dose region, where scotoma did not increase with time. The pattern and time course of visual field loss in the different radiation dose regions tended to support the conclusion that isodose calculations are accurate. The data were consistent with the hypothesis that visual loss secondary to irradiation results primarily from radiation vasculopathy and not from direct damage to photoreceptors or ganglion cells. Development of an absolute scotoma may require a dose in excess of 5,000 rads.

Effect of various doses of radiation for uveal melanoma on regression, visual acuity, complications, and survival.

We reviewed 284 choroidal and ciliary body melanomas treated with 50, 60, 70, or 80 gray equivalents (GyE) of helium ion radiation. Multivariate methods of data analysis were used to adjust for differences between dose groups with respect to the characteristics of patients (and their tumors). Radiation dose level did not affect survival, complications, visual outcome, or tumor regression in this model. The minimum radiation dose necessary to achieve tumor control with charged particles may be less than 50 GyE.

Ultrasonographic measurement of uveal melanoma thickness: interobserver variability.

We retrospectively reviewed ultrasonographic data on 32 uveal melanomas that had been studied both at a referral institution and at our centre within a six-week period. Generally there were good correlations between ultrasonographic measurements of tumour thickness. The mean absolute difference in ultrasound measurements of tumour thickness was 0.64 mm (range 0-2.2 mm); the mean tumour thickness was 5.2 mm (range 3.5-10.2 mm). Tumour diameter, location, the relative ultrasonographic experience with uveal melanoma, type of equipment, and tumour thickness all affected the interobserver variation of measurement.

Choroidal melanoma growth patterns.

Thirty patients with choroidal melanoma in whom tumour thickness was found to increase on serial examination were retrospectively studied. Often when tumours started to increase in thickness, after a period of relative quiescence, the growth rate was relatively rapid. Increased tumour thickness was associated with increased tumour growth. During the phase of active tumour growth the height of the lesion tended to increase more than exponentially. Possible inadvertent biases in the selection of the patients studied prohibit wide-ranging conclusions from these data.

N-3-pyridylmethyl-N'-p-nitrophenylurea ocular toxicity in man and rabbits.

Ingestion of the rat poison N-3-pyridylmethyl-N'-p-nitrophenylurea (PNU) produced ocular toxicity in three humans and in an animal model, the Dutch Belted rabbit. The electroretinogram b wave was especially susceptible to the effects of the rodenticide, and the target tissue appeared to be the retinal pigment epithelium. Injection of PNU itself did not produce ocular toxicity. The poison had to be administered orally. Gentamicin administered orally with PNU prevented the ocular toxicity. Presumably this antibiotic killed those gastrointestinal bacteria responsible for PNU's metabolism into an ocular toxin. L-tryptophan, a known antidote for the lethal effects of PNU, was an antidote for the ocular toxicity when administered orally but not when administered parenterally.

Diffuse melanoma of the choroid.

An 81-year-old woman with good vision was followed up with the diagnosis of a minimally active melanoma. This tumour was eventually found to be a diffuse melanoma with extraocular extension. Diffuse melanomas of the uvea are difficult to diagnose, have frequent and early extrascleral extension, and have a poorer prognosis than most melanomas of the uveal tract.

Uveal melanoma with opaque media: absence of definitive diagnosis before enucleation.

It is often difficult to make a correct diagnosis of a uveal melanoma in an eye with opaque media. A patient with a blind, painful eye and opaque media was evaluated clinically and with computed axial tomography and ultrasonography. We were unable to establish the definitive diagnosis of a uveal melanoma until the eye was examined histologically. Necrotic melanomas usually present with inflammatory signs, may produce opaque media and can be difficult to diagnose with clinical and imaging studies.

Contrast-enhanced MRI lesions during treatment with interferonbeta-1b predict increase in T1 black hole volume in patients with relapsing-remitting multiple sclerosis.

T1 black holes (BH) have been found to represent focal areas of substantial central nervous system tissue damage in multiple sclerosis (MS) patients. We examined the development of T1 BH over a three-year period of treatment with interferon (IFN)beta-1b in a group of 20 patients with relapsing-remitting MS. The number of contrast-enhancing lesions (CEL) after one year of treatment predicted a change in the T1 BH volume in the following two years. In patients without CEL, the T1 BH volume remained stable, whereas it increased in patients with CEL. The occurrence of CEL in patients treated with IFNbeta may indicate a heightened risk of accumulating T1 BH.

Interferon-beta-1b effects on re-enhancing lesions in patients with multiple sclerosis.

Interferon-beta (IFNbeta) reduces the number and load of new contrast-enhancing lesions (CELs) in patients with multiple sclerosis (MS). However, the ability of IFNbeta to reduce lesion sizes and re-enhancements of pre-existing CELs has not been examined extensively. Activity of contrast re-enhancing lesions (Re-CELs) and contrast single-enhancing lesions (S-CELs) were monitored in ten patients with relapsing-remitting (RR) MS. These patients underwent monthly post-contrast magnetic resonance imaging (MRIs) for an 18-month natural history phase and an 18-month therapy phase with subcutaneous IFNbeta-1b, totaling 37 images per patient. The activity was analysed using the first image as a baseline and registering subsequent active monthly images to the baseline. There was a 76.4% reduction in the number of CELs with IFNbeta therapy. The decrease was greater (P = 0.003) for S-CELs (82.3%) than for Re-CELs (57.4%). S-CELs showed no changes in durations of enhancement and maximal lesion sizes with treatment. Exclusively for Re-CELs, IFNbeta-1b significantly decreased maximal lesion sizes, total number of enhancement periods and total months of enhancement. Thus, IFNbeta appears to be effective in reducing the degree of severity of inflammation among Re-CELs, as reflected by their reduced maximal lesion sizes and durations of enhancement.