Quantification of DTI in the Pediatric Spinal Cord: Application to Clinical Evaluation in a Healthy Patient Population.

BACKGROUND AND PURPOSE: The purpose of the study is to characterize diffusion tensor imaging indices in the developing spinal cord, evaluating differences based on age and cord region. Describing the progression of DTI indices in the pediatric cord increases our understanding of spinal cord development. MATERIALS AND METHODS: A retrospective analysis was performed on DTI acquired in 121 pediatric patients (mean, 8.6 years; range, 0.3-18.0 years) at Monroe Carell Jr. Children's Hospital at Vanderbilt from 2017 to 2018. Diffusion-weighted images (15 directions; b = 750 s/mm2; slice thickness, 5 mm; in-plane resolution, 1.0 × 1.0 mm2) were acquired on a 3T scanner in the cervicothoracic and/or thoracolumbar cord. Manual whole-cord segmentation was performed. Images were masked and further segmented into cervical, upper thoracic, thoracolumbar, and conus regions. Analyses of covariance were performed for each DTI-derived index to investigate how age affects diffusion across cord regions, and 95% confidence intervals were calculated across age for each derived index and region. Post hoc testing was performed to analyze regional differences. RESULTS: Analyses of covariance revealed significant correlations of age with axial diffusivity, mean diffusivity, and fractional anisotropy (all, P < .001). There were also significant differences among cord regions for axial diffusivity, radial diffusivity, mean diffusivity, and fractional anisotropy (all, P < .001). CONCLUSIONS: This research demonstrates that diffusion evolves in the pediatric spinal cord during development, dependent on both cord region and the diffusion index of interest. Future research could investigate how diffusion may be affected by common pediatric spinal pathologies.

Do repeat ultrasounds affect orchiectomy rate in patients with testicular torsion treated at a pediatric institution?

INTRODUCTION: Testicular torsion is a urological emergency; as the testicular salvage rate decreases with time, prompt intervention is required to restore the blood flow. Interhospital transfers and ultrasound examinations, while clinically essential to proper treatment and diagnosis, may adversely affect outcomes by delaying surgical intervention. Patients transferred to another institution for treatment of testicular torsion may experience a further time delay by undergoing two ultrasound examinations: one at the initial admitting institution and one at the receiving institution. To the knowledge of the authors, no study has yet explored the time delays and outcomes associated with these repeat ultrasounds. OBJECTIVE: The objective was to investigate the impact of repeat ultrasound imaging on time to treatment and patient outcomes in patients with testicular torsion. STUDY DESIGN: A retrospective chart review of 133 patients, aged 0-20 years, treated at the authors' institution for testicular torsion was conducted. Neonate patients and patients who did not receive ultrasound were excluded. Demographic and clinical variables were collected from the electronic medical record. Pearson Chi-squared and t-tests were used for univariate comparisons, and multivariate logistic regression analysis was performed to measure the relationships between variables. RESULTS: Forty-nine percent of patients were primary patients, and 51% were transfer patients. Fifty-two percent of transfer patients received repeat ultrasounds. In comparison to salvaged patients, those who underwent orchiectomy experienced a greater delay between presentation at the institution and surgical intervention (229 min vs 177 min, p = 0.048). The transfer status does not appear to be related to the outcome, i.e. orchiectomy versus salvage. Patients who underwent orchiectomy were more likely than salvaged patients to have received repeat ultrasounds (p = 0.008). Repeat ultrasound patients had three times the likelihood of orchiectomy of single ultrasound patients. In a subset analysis of transfer patients, repeat ultrasound patients were more likely than single ultrasound patients to receive an orchiectomy (p = 0.03). DISCUSSION: In agreement with previous studies, patients who underwent orchiectomy were found to experience greater treatment delays and trend toward transfer. Specifically, repeat ultrasound and time between presentation and intervention appear to influence patient outcomes. The effect of repeat ultrasound on outcomes appears to be independent of the transfer status. The study was limited by its retrospective nature and small sample size. CONCLUSION: The analysis suggests that efforts to prevent repeat ultrasounds and minimize the time between presentation and intervention would improve patient outcomes. It is proposed that standardized clinical decision-making procedures, such as the TWIST scoring system, be incorporated into hospital protocols.

Interdisciplinary pain management is beneficial for refractory orchialgia in children.

INTRODUCTION: Idiopathic testicular/groin pain can be a difficult entity for children, their families, and caregivers. The role of interdisciplinary pain management has previously been demonstrated in treating chronic orchialgia at the present pediatric pain clinic. OBJECTIVE: To evaluate the role of interdisciplinary pain management in managing refractory orchialgia. It was hypothesized that children with refractory orchialgia might respond well. Interdisciplinary care was defined as that which crosses two medical disciplines such as a surgical specialty and specialist in analgesia. SUBJECTS AND METHODS: Pediatric patients were identified who were: ≥ 10 years old; evaluated in the pediatric urology clinic between 2002 and 2012; were diagnosed wtih ICD code 608.9 or had the diagnosis of male genital disorder NOS. Children were included if they presented with orchialgia without an identifiable cause and failed conservative management (rest, scrotal support, Sitz bath, timed voiding, constipation avoidance) including conventional anti-nociceptive analgesics (acetaminophen, non-steroidal anti-inflammatory drugs, opioids). Patient electronic medical records were reviewed retrospectively. RESULTS: Twenty-two children met inclusion criteria. Mean age was 13.7 years (range 10-17). Nearly half (45%) of the children had chronic medical conditions such as asthma, allergies, and obesity. Twenty-one of the 22 children were referred to the pediatric pain clinic; 15 were evaluated, and one refused treatment. All children evaluated in the pediatric pain clinic were initially offered an empiric anti-neuropathic anti-convulsant (i.e. gabapentin) and/or an anti-depressant (i.e. amitriptyline) before being offered a nerve block. Of the 14 children accepting treatment in the pediatric pain clinic, six were treated solely with an empiric anti-neuropathic anti-convulsant and/or anti-depressant; eight received medications followed by nerve block (seven ilioinguinal-iliohypogastric blocks, one spinal and ilioinguinal-iliohypogastric block) (see Fig. 1). A total of eight of the 14 children (57%) treated by the pain clinic had resolution of pain, with 50% of those treated with medications alone (three out of six children) responding (two responding to gabapentin and a tricyclic antidepressant, one to gabapentin alone); and five out of eight (63%) treated with medications and then nerve block (ilioinguinal-iliohypogastric block) responding. Of the eight children undergoing nerve block, five required more than one block. The time between each block ranged from 4 to 22.6 weeks. Response to nerve block required an average of 1.4 procedures (range 1-2); mean follow-up after nerve block was 2.4 months (range 0.1-4.8). DISCUSSION: Children with refractory orchialgia often have comorbidities that suggest a multidisciplinary approach would be useful for treating them. The present study found that the majority of children with refractory orchialgia treated in the pediatric pain clinic responded to management. Major limitations, however, included small cohort size and short follow-up, particularly in those children undergoing nerve block. There was also no objective assessment of pain improvement or improvement in quality of life, which could be rectified with a prospective study. CONCLUSION: Collaboration and early referral for interdisciplinary pain management as one of these multidisciplinary approaches may help to coordinate care and ease patient suffering.

Can magnetic resonance spectroscopy predict neurodevelopmental outcome in very low birth weight preterm infants?

OBJECTIVE: To determine if metabolite ratios at near-term age predict outcome in very low birth weight preterm infants at 18 to 24 months adjusted age. STUDY DESIGN: Thirty-six infants (birth weight

1H spectroscopy without solvent suppression: characterization of signal modulations at short echo times.

While most proton ((1)H) spectra acquired in vivo utilize selective suppression of the solvent signal for more sensitive detection of signals from the dilute metabolites, recent reports have demonstrated the feasibility and advantages of collecting in vivo data without solvent attenuation. When these acquisitions are performed at short echo times, the presence of frequency modulations of the water resonance may become an obstacle to the identification and quantitation of metabolite resonances. The present report addresses the characteristics, origin, and elimination of these sidebands. Sideband amplitudes were measured as a function of delay time between gradient pulse and data collection, as a function of gradient pulse amplitude, and as a function of spatial location of the sample for each of the three orthogonal gradient sets. Acoustic acquisitions were performed to demonstrate the correlation between mechanical vibration resonances and the frequencies of MR sidebands. A mathematical framework is developed and compared with the experimental results. This derivation is based on the theory that these frequency modulations are induced by magnetic field fluctuations generated by the transient oscillations of gradient coils.

Water modeled signal removal and data quantification in localized MR spectroscopy using a time-scale postacquistion method.

We have previously shown the continuous wavelet transform (CWT), a signal-processing tool, which is based upon an iterative algorithm using a lorentzian signal model, to be useful as a postacquisition water suppression technique. To further exploit this tool we show its usefulness in accurately quantifying the signal metabolites after water removal. However, due to the static field inhomogeneities, eddy currents, and "radiation damping," the water signal and the metabolites may no longer have a lorentzian lineshape. Therefore, another signal model must be used. As the CWT is a flexible method, we have developed a new algorithm using a gaussian model and found that it fits the signal components, especially the water resonance, better than the lorentzian model in most cases. A new framework, which uses the two models, is proposed. The framework iteratively extracts each resonance, starting by the water peak, from the raw signal and adjusts its envelope to both the lorentzian and the gaussian models. The model giving the best fit is selected. As a consequence, the small signals originating from metabolites when selecting, removing, and quantifying the dominant water resonance from the raw time domain signal are preserved and an accurate estimation of their concentrations is obtained. This is demonstrated by analyzing (1H) magnetic resonance spectroscopy unsuppressed water data collected from a phantom with known concentrations at two different field strengths and data collected from normal volunteers using two different localization methods.