Intraocular penetration of liposomal amphotericin B after intravenous injection in inflamed human eyes.

PURPOSE: To determine the intraocular penetration of amphotericin B (AMPH-B) after an intravenously injection of liposomal amphotericin B (L-AMB) in inflamed human eyes. METHODS: Seven eyes of 5 patients with fungal eye diseases (endophthalmitis in 6 eyes and keratitis in 1 eye) were treated with intravenous injections of 100-250 mg/day of L-AMB. Samples of blood, corneal button, aqueous humor, and vitreous humor were collected and assessed for AMPH-B. RESULTS: The AMPH-B level in the cornea (604.0 µg/g) of the case with fungal keratitis exceeded the minimum inhibitory concentration. However, the levels in the aqueous and vitreous humors of the cases with fungal endophthalmitis were lower, e.g., 0.02 ± 0.01 µg/ml (0.09% of serum level) in the aqueous humor and 0.05 ± 0.08 µg/ml (0.17% of serum level) in the vitreous humor. CONCLUSIONS: The AMPH-B levels administered intravenously were very low in the aqueous and vitreous humors. Our findings indicate that intravenous L-AMB can be considered only for patients with mild endogenous fungal endophthalmitis, e.g., isolated chorioretinitis without vitreous extensions.

Novel practical SNR determination method for MRI using double echo with longest second echo time (DELSET).

OBJECTIVE: We devised a practical method using double echo with the longest second echo time (DELSET) for simple and accurate signal-to-noise ratio (SNR) measurement of MRIs. METHODS: The DELSET method is based on the double-echo sequence in which the first and second echo times (TE) are set, respectively, as the clinically acceptable time for the signal image and as the longest time for the noise image. The second TE needs to be at least 8 times longer than T2 (for spin-echo) or T2* (for gradient-echo) of the objective tissue. For example, second TE > 560 ms for the case of T2 = 70 ms: the real part of signal intensity theoretically reaches the same order of magnitude as the quantization limit, due to the T2 relaxation process. SNR was calculated by dividing mean signal intensity in the first echo image by signal standard deviation (SD) in the second echo image in identical regions of interest after necessary noise correction. We determined the SNRs of cylindrical phantom images with different coils [quadrature (QD) and array coils] and sequences (spin-echo and spoiled gradient-echo sequences) and compared them between the DELSET and subtraction or background methods. The ratio of the mean signal intensity and SD in the second echo image with QD coil was determined to confirm whether the signal intensity had reached noise level. RESULTS: There were no significant differences in the phantom SNRs with both coils and sequences when DELSET was compared with the other two methods (p > 0.05 for all). The ratios of mean signal intensity and SD in the second echo images with both sequences were found to be in general agreement with a theoretical value. It was possible to obtain SNR images of the phantom, brain and abdomen with the DELSET method. CONCLUSION: The DELSET method enables simple and accurate SNR quantification. This practical method is applicable to in vivo parallel imaging. Advances in knowledge: Practical SNR quantification based on the DELSET method is feasible for application in MRI systems used clinically.

An eleven-year retrospective study of endogenous bacterial endophthalmitis.

Purpose. To determine the clinical features, microbial profiles, treatment outcomes, and prognostic factors for endogenous bacterial endophthalmitis (EBE). Methods. The medical records of 27 eyes of 21 patients diagnosed with EBE for 11 years were reviewed. Collected data included age, site of infection, visual acuities (VAs), microbial profiles, and treatment regimen. Results. The mean age was 68.5 years. Gram-positive organisms accounted for 76.2%, while gram-negative ones accounted for 19.0%. Staphylococcus aureus was the most common causative organism (52.3%) of which 72.7% was methicillin-resistant S. aureus. A final VA of ≥20/40 was achieved in 44% and 20/200 or better was in 64%. Eyes with initial VA of ≥20/200 (P = 0.003) and focal involvements (P = 0.011) had significantly better final VA. Initial VA (P = 0.001) and the interval between onset of ocular symptoms and intravitreal antibiotic injection (P = 0.097) were associated with final VA in eyes receiving intravitreal antibiotics. Conclusions. EBE is generally associated with poor visual outcome; however the prognosis may depend on initial VA, extent of ocular involvement, and an interval between onset of ocular symptoms and intravitreal antibiotic injection. Early diagnosis and early intravitreal injection supplement to systemic antibiotics might lead to a relatively good visual outcome.

Intraocular penetration of intravenous micafungin in inflamed human eyes.

Eight eyes of 7 patients with fungal disease received intravenous injections of 150 to 300 mg micafungin, and samples of blood, cornea, retina-choroid, aqueous humor, and vitreous humor were collected. The micafungin levels in all collected samples exceeded the MICs; however, the levels in the vitreous and aqueous humors were lower. Our findings suggest that intravenous micafungin should be given in combination with intravitreal antifungal agents after vitrectomy in severe cases of intraocular fungal diseases.

Intraocular penetration of itraconazole in patient with fungal endophthalmitis.

The purpose of this study was to determine the penetration of itraconazole, a type of azole antifungal agent, into the aqueous humor and vitreous after repeated oral administrations. Fungal endophthalmitis developed bilaterally in a 21-year-old man who had a history of intravenous hyperalimentation following abdominal surgery. Itraconazole capsules (200 mg/day) were taken orally for 12 consecutive days. Vitrectomy was performed on the left eye 30 h after the last oral itraconazole. Samples of blood, aqueous, and vitreous were collected during the vitrectomy. The concentration of itraconazole was determined by high performance liquid chromatography. The concentration of itraconazole was 0.492 µg/mL in the plasma, 0.020 µg/mL in the vitreous, and none in the aqueous of the left eye. Although no fungal organisms were isolated from the plasma and vitreous samples from both eyes, fungal DNA was detected in the vitreous from the left eye. Our findings indicate that oral itraconazole has limited penetration in eyes with fungal endophthalmitis.