Variation assessment of deformable registration in stereotactic radiosurgery.

INTRODUCTION: The regular functions of CT-MRI registration include delineation of targets and organs-at-risk (OARs) in radiosurgery planning. The question of whether deformable image registration (DIR) could be applied to stereotactic radiosurgery (SRS) in its place remains a subject of debate. METHODS: This study collected data regarding 16 patients who had undergone single-fraction SRS treatment. All lesions were located close to the brainstem. CT and MRI two image sets were registered by both rigid image registration (RIR) and DIR algorithms. The contours of the OARs were drawn individually on the rigid and deformable CT-MRI image sets by qualified radiation oncologists and dosimetrists. The evaluation metrics included volume overlapping (VO), Dice similarity coefficient (DSC), and dose. The modified demons deformable algorithm (VARIAN SmartAdapt) was used for evaluation in this study. RESULTS: The mean range of VO for OARs was 0.84 ± 0.08, and DSC was 0.82 ± 0.07. The maximum average volume difference was at normal brain (17.18 ± 14.48 cm3) and the second highest was at brainstem (2.26 cm3 ± 1.18). Pearson correlation testing showed that all DIRs' OAR volumes were linearly and significantly correlated with RIRs' volume (0.679-0.992, two tailed, P << 0.001). The 100% dose was prescribed at gross tumor volume (GTV). The average maximum percent dose difference was observed in brainstem (26.54% ± 27.027), and the average mean dose difference has found at same organ (1.6% ± 1.66). CONCLUSION: The change in image-registration method definitely produces dose variance, and is significantly more what depending on the target location. The volume size of OARs, however, was not statistical significantly correlated with dose variance.

Development of a simple computerized torsion test to quantify subjective ocular torsion.

PurposeThe double Maddox-rod test (DMRT) and Lancaster red-green test (LRGT) are the most widely used tests worldwide to assess subjective ocular torsion. However, these tests require equipment and the quantified results of ocular torsion are only provided in rough values. Here we developed a novel computerized torsion test (CTT) for individual assessment of subjective ocular torsion and validated the reliability and accuracy of the test compared with those of the DMRT and LRGT.MethodsA total of 30 patients with cyclovertical strabismus and 30 controls were recruited. The CTT was designed using Microsoft Office PowerPoint. Subjects wore red-green filter spectacles and viewed gradually tilted red and cyan lines on an LCD monitor and pressed the keyboard to go through the slides, until both lines seemed parallel. All subjects underwent the CTT, DMRT, and LRGT. Intraclass correlation coefficients and Bland-Altman plots were analyzed to assess the acceptability of the CTT compared with that of the DMRT.ResultsBoth the DMRT and CTT showed no significant test-retest differences in the strabismus and control groups. The DMRT and CTT results demonstrated an acceptable agreement. The reliability of the CTT was better than that of the DMRT. The LRGT showed low sensitivity for the detection of ocular torsion compared with the DMRT (40.0%) and CTT (39.1%).ConclusionOur results suggest that the assessment of subjective ocular torsion using the CTT based on PowerPoint software is simple, reproducible, and accurate and can be applied in clinical practice.

Incidence of toxic optic neuropathy with low-dose ethambutol.

OBJECTIVE: To investigate the incidence of ethambutol (EMB) induced optic neuropathy prescribed at a relatively low dose of ≤ 15 mg/kg/day for the treatment of tuberculosis (TB) or Mycobacterium avium complex (MAC) lung disease. DESIGN: Patients diagnosed with TB or MAC lung disease received multidrug regimens including EMB at a single institution from August 2003 to July 2009. Visual monitoring was performed at baseline and at regular follow-up. The incidence of EMB-induced visual disturbances was evaluated. RESULTS: Of the 415 patients included in the study, three (0.7%) developed toxic optic neuropathy over the 6-year period. Of the 289 patients prescribed a dose of ≤ 15 mg/kg/day EMB, only one (0.3%) developed toxic optic neuropathy. CONCLUSIONS: The incidence of EMB-induced optic neuropathy among Koreans is estimated to be 0.7%, and can be reduced with lower doses of EMB.

Association of superior oblique muscle volumes with the presence or absence of the trochlear nerve on high-resolution MR imaging in congenital superior oblique palsy.

BACKGROUND AND PURPOSE: Congenital superior oblique palsy is known to relate to trochlear nerve absence and a variable degree of superior oblique muscle hypoplasia. The purpose of this study was to determine whether superior oblique muscle volume predicts trochlear nerve absence in congenital superior oblique palsy. MATERIALS AND METHODS: A retrospective study of high-resolution MR imaging to evaluate the presence of the trochlear nerve and to measure superior oblique muscle areas and volumes with the image analysis tools of a PACS was performed in 128 consecutive patients with unilateral congenital superior oblique palsy and 34 age-matched healthy controls. RESULTS: Of the 128 patients with congenital superior oblique palsy, 88 had an ipsilateral trochlear nerve absence (absent group) and 40 had both trochlear nerves (present group). In patients with congenital superior oblique palsy, the paretic side superior oblique muscle volume was significantly smaller compared with the normal side only in the absent group (P < .001). The left and right side superior oblique muscle volumes were not significantly different in controls (P = .750), and the paretic and normal side superior oblique muscle volumes were not significantly different in the present group (P = .536). The cutoff value of the paretic/normal side superior oblique muscle volume ratio for diagnosing trochlear nerve absence was ≤0.75 (sensitivity 98.9%, specificity 95.0%) in patients with congenital superior oblique palsy. CONCLUSIONS: The ratio of paretic/normal side superior oblique muscle area and volume has an excellent predictability in diagnosing trochlear nerve absence in congenital superior oblique palsy.

MR imaging of congenital or developmental neuropathic strabismus: common and uncommon findings.

BACKGROUND AND PURPOSE: High-resolution MR imaging enables direct imaging of the ocular motor nerves. The aim of this study was to assess the various causes of congenital or developmental neuropathic strabismus by using high-resolution MR imaging. MATERIALS AND METHODS: High-resolution MR imaging was performed to evaluate the ocular motor nerves (CNIII, CNIV, CNVI) in 247 consecutive patients with suspected congenital or developmental neuropathic strabismus. These MR images, along with those obtained from conventional MR imaging of the brain and the orbit, were evaluated. RESULTS: MR imaging abnormalities were found in 112 patients: ocular motor nerve abnormalities in 98 patients (88%), orbital abnormalities in 9 patients (8%), and brain abnormalities in 5 patients (4%). Ocular motor nerve abnormalities were CNIV aplasia (63%), CNVI aplasia or hypoplasia (21%), CNIII aplasia or hypoplasia (3%), and combined CNIII aplasia and CNVI hypoplasia (1%). Orbital abnormalities were EOM hypoplasia (7%), EOM hypertrophy (1%), and fibrotic mass (1%). Brain abnormalities were periventricular leukomalacia (4%) and periventricular heterotopia (1%). CONCLUSIONS: Various MR imaging abnormalities were associated with congenital and developmental neuropathic strabismus. The most common abnormality was CNIV aplasia.

High-resolution 3D MR imaging of the trochlear nerve.

BACKGROUND AND PURPOSE: The cisternal segment of the trochlear nerve is difficult to identify reliably by routine MR imaging. We investigated the visibility and anatomic features of the trochlear nerve by using high-resolution 3D-bTFE imaging in healthy subjects. MATERIALS AND METHODS: This study was conducted with 32 healthy subjects without ocular movement disorders. For us to visualize the cisternal segment of the trochlear nerve, all subjects underwent 3D-bTFE imaging at 3T with 2 different resolutions: conventional resolution (voxel size, 0.67 x 0.45 x 1.4 mm) and high resolution (voxel size, 0.3 x 0.3 x 0.25 mm). Visibility of the trochlear nerve was graded with the use of a qualitative scale of certainty as follows: definite, probable, and indeterminate. The diameter of the trochlear nerve was measured. RESULTS: On conventional-resolution images, the visibility of the trochlear nerve was definite in 3 nerves, probable in 12 nerves, and indeterminate in 49 nerves. On high-resolution images, visibility was definite in 63 nerves and probable in 1 nerve. The mean diameter of the trochlear nerve was 0.54 mm (range, 0.35-0.96 mm). CONCLUSIONS: The trochlear nerve was visualized 100% of the time on high-resolution imaging with a voxel smaller than the nerve diameter. High-resolution imaging should have an important role in investigating the pathogenic mechanism of neuropathic strabismus, such as congenital superior oblique palsy.

Comparison of retinal nerve fibre layers between 11778 and 14484 mutations in Leber's hereditary optic neuropathy.

PURPOSE: To compare retinal nerve fibre layer (RNFL) thickness changes between mitochondrial DNA (mtDNA) mutations at nucleotides 11778 and 14484 in Leber's hereditary optic neuropathy (LHON) using optical coherence tomography (OCT). METHODS: Thirty LHON patients with mtDNA mutations at nucleotides 11778 or 14484 underwent full ophthalmologic examinations including Stratus OCT. Patients were divided into four groups according to disease duration (early 6 months) and mtDNA mutation type (11778 and 14484), and their RNFL thicknesses were compared. RESULTS: Average RNFL thickness in the early 11778 group was significantly greater than that in the early 14484 group (P=0.04). Average RNFL thickness in the late 11778 group was significantly less than that in the late 14484 group (P=0.02). Quadrant analysis of the superior, nasal, and inferior quadrant RNFL thickness in the late 11778 group showed more severe RNFL atrophy than in the late 14484 group (P=0.023, 0.015, 0.003, respectively). CONCLUSIONS: RNFL thickness was significantly increased in the early stage and decreased in the late stage in the 11778 group than in the 14484 group.

Prismatic correction of residual esotropia of 20 prism dioptres or less after full hypermetropic correction.

PURPOSE: To assess the efficacy of prismatic correction of residual esotropia

Refractive errors and strabismus in Asian patients with Down syndrome.

PURPOSE: The purpose of this study was to investigate the prevalence and patterns of refractive errors and strabismus in Asian patients with Down syndrome, as they relate to age.MethodsA total of 261 Korean patients with Down syndrome were examined between March 1999 and May 2007. Eighty-nine patients were excluded from the study. The remaining 172 patients were divided into four age groups (<3 years, 3-<6 years, 6-<9 years, and >or=9 years). Full ophthalmologic examinations and strabismus assessments were performed. Refractive errors were defined as follows: myopia >or=-1.00 D, hyperopia >or=+1.00 D, astigmatism >or=+/-1.00 D, and anisometropia as a refractive difference between the two eyes >or=1.00 D. RESULTS: Hyperopia (46.5%) was slightly more common than myopia (40.1%). The prevalence of myopia increased with age, whereas that of hyperopia decreased. Astigmatism was found in 66.8% of patients, and astigmatism >or=2 D was found in 16.8% of patients. Anisometropia was identified in 29.7% of patients, and the incidence of anisometropia correlated significantly with age as well as with astigmatism. Esotropia (22.1%) was twice as common as exotropia (10.5%). The prevalence of esotropia increased with age, but that of exotropia decreased. Fifty patients were found to have nystagmus (29.1%). CONCLUSIONS: In Asian patients with Down syndrome, esotropia was more common than exotropia and hyperopia was more common than myopia. The prevalence of exotropia and astigmatism was much higher in this study than has been previously reported.

The incidence of asystole in patients undergoing strabismus surgery.

PURPOSE: To investigate the incidence of asystole during strabismus surgery. DESIGN: Retrospective, noncomparative interventional case series. METHODS: Six months to 80 years of age of 3628 consecutive patients who underwent strabismus surgery from October 1994 to May 2007 were enrolled. RESULTS: Four patients (0.11%) under general anaesthesia showed asystole during strabismus surgery. All four were adults of 28, 32, 50, and 53 years of age. Two patients had hypertension and three had preoperative electrocardiographic abnormalities. Three patients had previously undergone uneventful strabismus surgery. CONCLUSIONS: Asystole is likely to be encountered during strabismus surgery with an incidence of ca. 0.11%.

Emergence of diplopia and oscillopsia due to Heimann-Bielschowsky phenomenon after cataract surgery.

The Heimann-Bielschowsky phenomenon (HBP) refers to coarse vertical oscillation of the eye with impaired vision. The ocular movements are strictly monocular, occurring only in the eye with amblyopia. The vertical oscillation is of equal velocity in both vertical directions, or may sometimes be greater in the downward than upward direction. HBP develops several years after loss of vision. It can be differentiated from dissociated nystagmus in spasmus nutans, congenital nystagmus and internuclear ophthalmoplegia based on the strict unilaterality, vertical direction and low frequency. Previously, only a few reports described the development of oscillopsia due to HBP after cataract surgery, which resolved spontaneously or responded to gabapentin. However, visual impairments due to diplopia or oscillopsia from HBP after cataract surgery have received little attention. We report a man who developed persistent vertical diplopia and oscillopsia due to HBP after a cataract operation, which markedly impaired his vision.

Intraoperative extraocular Indocyanine Green (IE-ICG) dye test: a new method of detecting a peeled internal limiting membrane.

AIMS: To develop an intraoperative, extraocular Indocyanine Green dye staining test (IE-ICG) for the differentiation of a peeled ILM from a thin epiretinal membrane, and to evaluate its efficacy. METHODS: This was a consecutive observational case and laboratory observational series. We performed ILM peeling in patients with an idiopathic macular hole (MH, n = 10) and diabetic macular oedema (DME, n = 10) without vital dye staining such as ICG or Trypan Blue. We also performed membrane peeling in patients with an idiopathic epiretinal membrane (ERM, n = 10). Then, the peeled membranes were stained with ICG (1.25 mg/ml) beyond the operation field and examined under a light microscope. After this examination, membranes were fixed with glutaraldehyde, and an electron microscope was used to confirm whether they were ILMs or thin ERM. The concordance rates between surgeon's intraoperative impression of membranes (SI), IE-ICG results (IT) and histological findings (HF) of peeled membranes were evaluated to reveal the efficacy of IE-ICG. RESULTS: The ILMs were homogenously stained with ICG dye (positive IE-ICG), and the ERMs were not stained at all by ICG dye (negative IE-ICG). The concordance rate between IT and HF was 100% in all three groups of patients. However, concordance rates between SI and IT were 100% in MH, 80% in DME and 50% in ERM, respectively. The surgeon's impression of the membrane is inaccurate, especially in patients with idiopathic epiretinal membrane. CONCLUSION: Considering the cost, difficulties of tissue preparation, and the time-consuming process of histological confirmation of an ILM, IE-ICG may be a useful alternative for the differentiation of a peeled ILM and a thin ERM.

Optical coherence tomography in a patient with tobacco-alcohol amblyopia.

AIM: To report optical coherence tomography (OCT) finding in a patient with tobacco-alcohol amblyopia. METHODS: A 45-year-old man presented with a gradual decrease in vision over 4 years. He had smoked a half to one pack of cigarettes per day and had consumed 350 cc of gin per day for 30 years. A detailed ophthalmologic examination was performed. RESULTS: His corrected visual acuities were 20/800 OD and 20/200 OS. A Goldmann visual field examination showed ceco-central scotomas in both eyes. OCT using a peripapillary Fast RNFL (retinal nerve fiber layer) programme showed a small decrease in the RNFL thickness of the superotemporal quadrant in the normative diagram of the right eye in spite of a markedly increased RNFL thickness in both eyes. CONCLUSION: During the phase of visual loss in a patient with tobacco-alcohol amblyopia, visual loss may precede optic disc changes as detected by OCT.

Clinical features and natural history of acquired third, fourth, and sixth cranial nerve palsy.

PURPOSE: Clinical features of acquired third, fourth, and sixth cranial nerve palsy showed variation among previous studies. Evaluation of natural course with objective criteria will establish accurate recovery rates and important factors for recovery. METHODS: Retrospective chart review was performed on 206 patients who visited a neuro-ophthalmic department with acquired third, fourth, and sixth nerve palsy. Aetiology and results of ocular exam on each visit were reviewed, and multivariate logistic regression analysis was performed to identify independent factors affecting recovery. RESULTS: The sixth cranial nerve was affected most frequently (n=108, 52.4%) and vascular disease (n=64, 31.1%) was the most common aetiology. Recovery was evaluated with change of deviation angle for 108 patients, who were first examined within a month of onset and followed up for at least 6 months. Ninety-two (85.2%) patients showed overall (at least partial) recovery and 73 (67.6%) showed complete recovery. In univariate analysis, initial deviation angle was found to be only significant factor associated with complete recovery (P=0.007) and most patients who experienced successful management of treatable underlying disease showed recovery. CONCLUSIONS: With objective criteria based on deviation angle, overall recovery rate from the third, fourth, and sixth nerve palsy was 85.2%. Patients who had smaller initial eyeball deviation or successful management of treatable underlying disease had a high chance of recovery.

Unilateral recession-resection in children with exotropia of the convergence insufficiency type.

PURPOSE: The surgical success rates for intermittent exotropia of the convergence insufficiency type have been reported to be variable, and most were studied retrospectively in adults. The purpose of this study was to evaluate prospectively the long-term surgical results of unilateral lateral rectus (LR) muscle recession and medial rectus (MR) muscle resection in children with intermittent exotropia of the convergence insufficiency type. METHODS: A total of 14 children with intermittent exotropia greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. The amounts of resection and recession were based on near and distance deviation, respectively. Minimum follow-up was 1 year (mean 26.6 months; range, 12-68 months) after surgery. The paired t-test was used to compare preoperative and postoperative measurements of the angle of deviation at distance and near, near-distance difference. RESULTS: Significant postoperative reduction was achieved in terms of mean distance exodeviation, from 22.5 PD to 9.1 PD (P=0.000), and mean near exodeviation from 33.8 PD to 13.6 PD (P=0.000). Mean near-distance difference reduced from 11.3 PD preoperatively to 4.6 PD postoperatively (P=0.000). Fresnel prism was used temporarily to treat postoperative esotropia in only one patient for postoperative 6 months. CONCLUSIONS: Unilateral surgery biased to MR strengthening more than LR weakening in children with intermittent exotropia of the convergence insufficiency type, was found to successfully reduce both distance and near deviation and to collapse near-distance differences with a low risk of long-term postoperative esotropia.

Berberine induces apoptosis through a mitochondria/caspases pathway in human hepatoma cells.

Berberine, a main component of Coptidis Rhizoma, is a plant alkaloid with a long history of medicinal use in Chinese medicine. Berberine has indicated significant antimicrobial activity against a variety of organisms including bacteria, viruses, fungi. The mechanism by which berberine initiates apoptosis remains poorly understood. In the present study, we demonstrated that berberine exhibited significant cytotoxicity in hepatoma HepG2 cells but is ineffective in Chang liver cells. Herein we investigated cytotoxicity mechanism of berberine in HepG2 cells. The results showed that HepG2 cells underwent internucleosomal DNA fragmentation after 24-h treatment with berberine (50 microM). Moreover, berberine induced the activation of caspase-8 and -3, and caused the cleavage of poly ADP-ribose polymerase (PARP) and the cytochrome c release, whereas the expression of Bid and anti-apoptosis factor Bcl-XL were decreased markedly. The loss of mitochondrial membrane potential (Delta psim) at 24 h and activation of Fas at 12 h were also seen in the berberine-treated HepG2 cells. These findings supported the fact that the inhibitors of caspases, DEVD-FMK, IETD-FMK and VAD-FMK, prevented apoptosis and restored the expression of Bcl-XL, Bcl-2 and Bid. These results indicated that the potential of anti-hepatoma activity of berberine may be mediated through a caspases-mitochondria-dependent pathway.

The long-term result of slanted medial rectus resection in exotropia of the convergence insufficiency type.

PURPOSE: To evaluate the long-term results of slanted medial rectus (MR) resection for intermittent exotropia (X(T)) of the convergence insufficiency type. METHODS: In all, 10 patients with an X(T) greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. Patients received slanted bilateral MR resection. The upper edge of the MR was resected according to the distance exodeviation and the lower edge of the MR was resected according to near exodeviation. The postoperative follow-up period was between 6 and 62 months with a mean of 38.9 months. The paired t-test was used to compare: mean distance angle of deviation preoperatively and postoperatively; mean near angle of deviation preoperatively and postoperatively; and mean near-distance exodeviation difference preoperatively and postoperatively. RESULTS: Bilateral slanted MR resections reduced mean exodeviation at distance from 23.0+/-7.2 to 16.3+/-5.4 PD (P=0.03); mean exodeviation at near from 34.3+/-7.7 to 24.6+/-6.9 PD (P=0.01); and mean near-distance difference from 11.4+/-2.6 to 8.3+/-3.5 PD (P=0.04). At the final follow-up examination, all patients demonstrated an exodeviation of 10 PD or more at distance and near, and the exodeviation difference between distance and near deviation was within 10 PD in five of the 10 patients. Three patients had an esodeviation at distance after surgery, but all resolved within 4 weeks. CONCLUSIONS: Bilateral slanted MR resections in patients with X(T) of the convergence insufficiency type resulted in undercorrection in all patients.