Fast-sequence MRI studies for surveillance imaging in pediatric hydrocephalus.

OBJECT: Surveillance imaging of the cerebral ventricles can be valuable in following up children with shunt-treated hydrocephalus. There also, however, has been recent increased awareness and concern over the potential risk associated with imaging-related radiation exposure in children. Magnetic resonance imaging represents an imaging alternative that does not use ionizing radiation; however, its practical utility has been limited due to the near-uniform requirement for sedation or general anesthesia in children. Magnetic resonance imaging without sedation is often futile because of the movement artifact produced by the nonsedated pediatric patient. Some studies have demonstrated the feasibility of using fast-sequence MRI (fsMRI), but the reported experiences are limited. The authors have incorporated fsMRI into their routine shunt surveillance imaging paradigms and report here a 5-year experience with this modality. METHODS: The authors initially started using fsMRI for routine surveillance in a single clinic in 2008 and have gradually increased their institutional utilization of this modality as experience has accumulated and protocols have been refined. Imaging sequences obtained for each child include an axial T2-weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE), coronal T2-weighted HASTE, and sagittal T2-weighted HASTE images. The authors conducted a retrospective chart and imaging review. They rated each fsMR image according to 5 visibility parameters: 1) ventricle size, 2) ventricle configuration, 3) presence or absence of transependymal flow, 4) presence or absence of motion artifact, and 5) visualization of the ventricular catheter. Each parameter was graded as 1 (present) or 0 (absent). Thus, the maximum value assigned to each scan could be 5 and the minimum value assigned to each scan could be 0. Interrater reliability between pairs of observers was calculated using the Kendall's tau-b and intraclass coefficients. RESULTS: Two hundred patients underwent fsMRI. No child required sedation. The average duration of examinations was approximately 3.37 minutes, and mean age of the patients was 5.7 years. Clinically useful images were attained in all cases. Overall quality of the fsMRI studies based on the 5 different visibility parameters showed that 169 images (84.5%) included 4 or 5 parameters (score ≥ 4) and had statistically significant excellent quality. The Kendall's tau-b for the overall fsMRI ratings was 0.82 (p = 0.002) and the intraclass coefficient was 0.87 (p < 0.0001). CONCLUSIONS: In the present cohort of 200 patients, fsMRI studies were shown to have an excellent overall quality and a statistically significant high degree of interrater reliability. Consequently, the authors propose that fsMRI is a sufficiently effective modality that eliminates the need for sedation and the use of ionizing radiation and that it should supplant CT for routine surveillance imaging in hydrocephalic patients.

Infections of pediatric cerebrospinal fluid shunts related to fundoplication and gastrostomy.

OBJECT: There is conflicting information in the literature regarding the increased risk of ventriculoperitoneal (VP) shunt infection after abdominal surgical procedures such as gastrostomy tube (GT) placement and Nissen fundoplication (NF) in the young patient. To further elucidate this potential association, the authors reviewed their institutional experience with such cases. METHODS: The authors retrospectively reviewed the records of all patients with shunted hydrocephalus who also underwent NF procedures and/or GT placements over a 9-year period. RESULTS: During this 9-year period, 3065 cerebrospinal fluid (CSF) shunts were placed and 1630 NF procedures/GT placements were performed. Ninety-six patients were identified who received both a CSF shunt and NF procedures/GT placements. Seventy-nine patients had a functioning VP shunt (without recent [< 6 months] CSF infection or shunt revision) at the time of their abdominal procedure (NF procedure or GT placement). Of this latter cohort, there were 38 males and 41 females with a mean age of 6.4 months; 12.7% of these patients developed a shunt infection and 60% of these infections were due to Staphylococcus species. CONCLUSIONS: Based on this study, an NF procedure/GT placement in a child with a VP shunt appears to carry approximately the same risk of shunt infection as a shunt placement operation. Moreover, the microbiology observed in these patients with infection did not differ significantly from the usual microorganisms responsible for VP shunt infections in infants/neonates. Finally, but not conclusively, an open NF procedure/GT placement may carry a higher infection risk than a laparoscopic-assisted NF procedure/GT placement.