Katherine Nimkin

Prospective Evaluation of MR Enterography as the Primary Imaging Modality for Pediatric Crohn Disease Assessment

OBJECTIVE The objectives of this study were prospective evaluation of MR enterographic accuracy for detecting Crohn disease imaging features in pediatric patients, compared with a CT reference standard, as well as determination of MR enterographic accuracy for detecting active bowel inflammation and fibrosis using a histologic reference standard. SUBJECTS AND METHODS The study group for this blinded prospective study included 21 pediatric subjects with known Crohn disease scheduled for clinical CT and histologic bowel sampling for symptomatic exacerbation. All subjects and their parents gave informed consent to also undergo MR enterography. CT and MR enterography examinations were independently reviewed by two radiologists and were scored for Crohn disease features. All bowel histology specimens were reviewed by a single pathologist for the presence of active mucosal inflammation and mural fibrosis, followed by correlation of imaging and histologic findings. RESULTS All 21 subjects underwent MR enterography and histologic sampling, 18 of whom also underwent CT. MR enterography had high sensitivity for detecting Crohn disease imaging features (e.g., bowel wall thickening, mesenteric inflammation, lymphadenopathy, fistula, and abscess) compared with CT, with individual sensitivity values ranging from 85.1% to 100%. Of a total of 53 abnormal bowel segments with correlation of MRI and histologic findings, MR enterography showed 86.7% accuracy (90.0% sensitivity and 82.6% specificity) for detecting active inflammation (p < 0.001). The accuracy of MR enterography for detecting mural fibrosis overall was 64.9%, compared with histology, but increased to 83.3% (p < 0.05) for detecting fibrosis without superimposed active inflammation. CONCLUSION MR enterography can substitute for CT as the first-line imaging modality in pediatric patients with Crohn disease, on the basis of its ability to detect intestinal pathologic abnormalities in both small and large bowel as well as extraintestinal disease manifestations. Additionally, MR enterography provides an accurate noninvasive assessment of Crohn disease activity and mural fibrosis and can aid in formulating treatment strategies for symptomatic patients and assessing therapy response.

Imaging of child abuse.

Skeletal imaging plays a critical role in the diagnosis of abuse. High-detail radiographs of the entire skeleton, at times supplemented with nuclear imaging, CT, US, and MR imaging, elucidate the variety of findings with this entity. The radiologists role includes careful analysis of clinical history, familiarity with typical osseous findings in abuse, and awareness of potential normal variants and pitfalls. An accurate diagnosis of abuse can then lead to appropriate measures to protect all family members at risk of serious injury.

MR imaging of benign fatty tumors in children: report of four cases and review of the literature

This study correlates the magnetic resonance imaging characteristics with the pathologic findings in rare benign fatty soft tissue tumors in four children. A review of the literature is presented. Two cases of infiltrating lipoma displayed bright signal on both T1- and T2-weighted images, similar to that observed in subcutaneous fat. Histological study revealed extensive muscle infiltration by mature fat, with some areas of total fatty replacement. The case of facial lipomatosis revealed an extensive process of fatty invasion of adjacent soft tissue and osseous deformity by mass effect of the tumor. This lesion was bright on T1- and T2-weighted images. Histopathologic examination showed widespread invasion of squamous mucosa and skeletal muscle. The single case of lipoblastoma involved the presacral region and right buttock. This lesion, although bright on both T1 and T2 weighting, was relatively hypointense to subcutaneous fat on T1. Microscopic examination revealed a well-encapsulated fatty mass made up of cells ranging from lipoblasts to mature lipocytes. In childhood, when fatty lesions are almost always benign, a morphologic characterization by magnetic resonance may be sufficient basis on which to make critical therapeutic judgements.

Distal humeral physeal injuries in child abuse: MR imaging and ultrasonography findings

Distal humeral physeal injuries, in particular, fracture-separation of the distal humeral epiphysis, can be seen in abused infants. Detection of physeal injury in an infant or toddler may indicate the possibility of unsuspected abuse, particularly when an appropriate history explaining the circumstance of the fracture is lacking. In addition, the extent of injury can be difficult to characterize on plain radiographs. Ultrasonography (US) and MR imaging (MRI) may be of value in diagnosis and may obviate the need for intraoperative arthrography. We present MRI findings in three abused children with distal humeral physeal injuries. Sonographic correlation is alos presented in one case.

The growing teratoma syndrome

Growing teratoma syndrome is defined as enlarging masses of mature teratoma following chemotherapy for malignant nonseminomatous germ-cell tumors. Typically, there is associated normalization of initially elevated serum tumor markers. We describe clinical and imaging findings in a case of growing teratoma syndrome originating from immature teratoma of the ovary in a 12-year-old girl. Familiarity with this unusual entity is important to avoid confusion with advancing malignancy.

Urolithiasis in a children’s hospital: 1985–1990

We performed a retrospective study of patients who had urinary tract stones and were seen at our hospital from 1985–1990. The study was intended to determine the prevalence of urolithiasis and optimal approaches to imaging. Clinical data and imaging studies of 87 patients were reviewed. The mean age was 15.7 years with a range of 3 months to 44 years. Fifty-four percent of patients were male. Most patients had a known predisposing cause for urolithiasis; patients with myelodysplasia and structural urologic problems predominated. Plain films were performed in 77 patients; 57% showed stones. Ultrasonograms were performed in 71 patients; 77% showed stones. Excretory urograms (EU) were performed in 49 patients; 84% showed either stones or their effect on the urinary tract. Computed tomographic (CT) scan was performed in 25 patients; all showed stones.

Imaging of child abuse

Diagnostic imaging plays a fundamental role in the evaluation of suspected physical abuse. Judicious application of modern imaging techniques to cases of suspected abuse aids in early and accurate diagnosis, leading to appropriate measures to protect all family members at risk of serious injury.

The Tailored Low Dose Fluoroscopic Voiding Cystogram for Familial Reflux Screening

PURPOSE Radionuclide voiding cystography is generally advocated as a screening study to detect familial reflux. We assessed the efficacy of tailored low dose fluoroscopic voiding cystography for this purpose. MATERIALS AND METHODS We evaluated 10 boys and 10 girls 9 months to 10 years old (mean age 5 years) who were siblings of patients known to have reflux. The technique used a low dose fluoroscopic system. A tailored voiding cystographic protocol was designed to minimize gonadal radiation dose. RESULTS Absence of reflux was confirmed in 10 patients. Mean fluoroscopy time was 19 seconds (range 14 to 22), resulting in mean gonadal radiation exposure of less than 1.5 mrad., which is comparable to the lowest reported doses with the radionuclide technique. After reflux was demonstrated in 10 patients the study was immediately converted to a standard fluoroscopic imaging technique to define lower tract anatomy and quantitate reflux, avoiding a second study. CONCLUSIONS Tailored low dose fluoroscopic voiding cystography appears to be a practical approach for the assessment of familial reflux.

Dose reduction in pediatric abdominal CT: use of iterative reconstruction techniques across different CT platforms

Dose reduction in children undergoing CT scanning is an important priority for the radiology community and public at large. Drawbacks of radiation reduction are increased image noise and artifacts, which can affect image interpretation. Iterative reconstruction techniques have been developed to reduce noise and artifacts from reduced-dose CT examinations, although reconstruction algorithm, magnitude of dose reduction and effects on image quality vary. We review the reconstruction principles, radiation dose potential and effects on image quality of several iterative reconstruction techniques commonly used in clinical settings, including 3-D adaptive iterative dose reduction (AIDR-3D), adaptive statistical iterative reconstruction (ASIR), iDose, sinogram-affirmed iterative reconstruction (SAFIRE) and model-based iterative reconstruction (MBIR). We also discuss clinical applications of iterative reconstruction techniques in pediatric abdominal CT.

Cine Magnetic Resonance Imaging With Simultaneous Audio to Evaluate Pediatric Velopharyngeal Insufficiency

OBJECTIVE To develop a protocol linking cine magnetic resonance (MR) imaging to simultaneously acquired audio recordings of specific phonatory tasks to evaluate velopharyngeal insufficiency (VPI) in children. DESIGN Institutional review board-approved development and application of a novel dynamic cine MR imaging protocol linked to simultaneously recorded audio. SETTING A tertiary care multidisciplinary pediatric airway center. PARTICIPANTS Three healthy adult volunteers and 5 pediatric volunteers (age range, 9.3-18.9 years; mean age, 12.4 years) from the multidisciplinary pediatric airway center with VPI who previously had undergone nasopharyngoscopy, videofluoroscopy, or both. INTERVENTIONS Cine MR imaging with simultaneously acquired audio files was performed in 3 adult volunteers to optimize the protocol and then in 5 pediatric volunteers meeting the inclusion criteria. MAIN OUTCOME MEASURES High-resolution cine MR images with clear intelligible audio recordings of specific phonatory tasks. RESULTS Using 3 healthy adult volunteers, a cine MR imaging VPI protocol was developed that links simultaneously acquired cine MR images to audio recordings of specific validated phonatory tasks. Five school-aged children with VPI from our multidisciplinary pediatric airway center were then enrolled and underwent cine MR imaging using this protocol. The cine MR images and audio recordings acquired were of sufficient diagnostic quality to evaluate VPI closure patterns in school-aged children with VPI. CONCLUSION Cine MR imaging linked to audio is a quick, safe, and well-tolerated dynamic diagnostic imaging tool that may eventually have the potential to guide more precisely the selection and application of surgical techniques for VPI.