Test-Retest and Interreader Reproducibility of Semiautomated Atlas-Based Analysis of Diffusion Tensor Imaging Data in Acute Cervical Spine Trauma in Adult Patients

BACKGROUND AND PURPOSE

DTI is a tool for microstructural spinal cord injury evaluation. This study evaluated the reproducibility of a semiautomated segmentation algorithm of spinal cord DTI.

MATERIALS AND METHODS

Forty-two consecutive patients undergoing acute trauma cervical spine MR imaging underwent 2 axial DTI scans in addition to their clinical scan. The datasets were put through a semiautomated probabilistic segmentation algorithm that selected white matter, gray matter, and 24 individual white matter tracts. Regional and white matter tract volume, fractional anisotropy, and mean diffusivity values were calculated. Two readers performed the nonautomated steps to evaluate interreader reproducibility. The coefficient of variation and intraclass correlation coefficient were used to assess test-retest and interreader reproducibility.

RESULTS

Of 42 patients, 30 had useable data. Test-retest reproducibility of fractional anisotropy was high for white matter as a whole (coefficient of variation, 3.8%; intraclass correlation coefficient, 0.93). Test-retest coefficient-of-variation ranged from 8.0%-18.2% and intraclass correlation coefficients from 0.47-0.80 across individual white matter tracts. Mean diffusivity metrics also had high test-retest reproducibility (white matter: coefficient-of-variation, 5.6%; intraclass correlation coefficient, 0.86) with coefficients of variation from 11.6%-18.3% and intraclass correlation coefficients from 0.57-0.74 across individual tracts, with better agreement for larger tracts. The coefficients of variation of fractional anisotropy and mean diffusivity both had significant negative relationships with white matter volume (26%-27% decrease for each doubling of white matter volume, P < .01).

CONCLUSIONS

DTI spinal cord segmentation is reproducible in the setting of acute spine trauma, specifically for larger white matter tracts and total white or gray matter.

Hearing loss and otitis media in velo-cardio-facial syndrome

There is an increased prevalence of otitis media and associated hearing loss in patients with isolated cleft or submucous cleft palates, palatal abnormalities which are well known components of velo-cardio-facial syndrome (VCFS). The records of 166 VCFS patients were reviewed for the purpose of documenting the prevalence of middle ear disease and associated conductive hearing loss in patients with VCFS. Patients were divided according to age, type of palatal abnormality and presence or absence of chromosomal deletion using fluorescence hybridization test. Results indicated that the prevalence of middle ear disease in patients with VCFS was 47% and the prevalence of hearing loss was 44%, the majority of which was conductive and due to middle ear disease (74%) and 11% of which was sensorineural. There was no statistical difference between groups using the chi2-test with regard to age, type of palatal abnormality and presence of chromosomal deletion. The prevalence of conductive hearing loss secondary to middle ear disease in VCFS is comparable to the prevalence found in isolated cases of cleft palate.

The effect of antiglaucoma drugs on rabbit aqueous humor proteins determined by gel electrophoresis

Previous studies indicate that there may be differences in the protein composition of the aqueous humor in normal and glaucomatous human eyes. These differences in protein composition and concentration may be due to the topical antiglaucoma medications used to treat glaucoma. These differences should be distinguished from any possible protein composition changes due to glaucoma. In order to study the effects of topical antiglaucoma medications on aqueous humor protein composition, we analyzed the aqueous humor of rabbit eyes topically treated with various antiglaucoma medications (timolol, pilocarpine, and dipivefrin). One eye of each rabbit was treated with the experimental drug, and the fellow eye was treated with saline solution (control). Thirty-six aqueous humor samples from 18 rabbits were obtained after 24 hours and 36 samples were obtained from 18 additional rabbits after 7 days of topical drug treatment. The protein composition of the aqueous humor samples was analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Significant protein differences in aqueous humor samples were found between the eyes treated with timolol and the control eyes, whereas no significant differences were found between the eyes treated with pilocarpine or dipivefrin and the controls. These protein differences ranged from 14,000 to 18,000 daltons in molecular weight.

Tau immunoreactivity associated with aluminum maltolate-induced neurofibrillary degeneration in rabbits

Intracisternal administration of aluminum maltolate to rabbits produces a marked argyrophilic neurofibrillary degeneration (NFD) which is also immunoreactive for both phosphorylated and non-phosphorylated microtubule associated protein tau. Using tissue fixation in PBF, the monoclonal antibodies Tau-2 and AT8 stain the NFD. Dephosphorylation markedly reduces the positivity of AT8. Using PLP-fixed tissue, monoclonal antibody Tau-1 also immunostains aluminum-induced NFD.

The quantitative measurement of spasticity: effect of cutaneous electrical stimulation

The goal of this research was to determine if cutaneous electrotherapy would temporarily reduce muscle spasticity. Five traumatically brain injured (TBI) and five spinal cord injured (SCI) subjects, all with clinically evident spasticity, received surface electrical stimulation over the tibialis anterior muscle. Using the Spasticity Measurement System, stiffness around the ankle was measured before, immediately after, and 24 hours after treatment. With stimulation, ipsilateral ankle viscoelastic stiffness immediately decreased in 9 of 10 subjects and remained significantly depressed for up to 24 hours. Contralateral ankle spasticity did not significantly change. Using the same subjects under sham conditions, no significant decrements in spasticity occurred. In a subjective survey, only SCI participants reported functionally evident spasticity reductions. Also within this subgroup, efficacy of treatment was directly proportional to the severity of pre-stimulation clonus. We conclude that (1) cutaneous electrotherapy transiently decreases both TBI and SCI related spasticity and (2) pre-stimulation clonus may function as a clinical indicator of SCI patients most likely to benefit from this process.

The effects of malnutrition on the motor, perceptual, and cognitive functions of Filipino children

The motor, perceptual, and cognitive abilities of 99 Filipino children, aged 4-6 years with a documented history of malnutrition from a nutritionally depressed area of Manila were determined using the Revised Manila Motor-Perceptual Screening Test. They were classified into four groups of: (1) normal; (2) acutely malnourished; (3) stunted but not malnourished; and (4) chronically malnourished using the Waterlow classification. Thirty-one normal children of comparable ages and background from a nationwide pool were similarly tested and served as the control group. Motor (p = 0.001) and perceptual skill (p less than 0.03 to less than 0.001) scores were significantly lower than in their normal counterparts, especially in the chronically malnourished children. Cognitive abilities were not evidently affected by malnutrition.