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Purpose: To compare the accuracies of computed tomography (CT), magnetic resonance (MR) imaging, and bone scintigraphy in staging disease in patients with neuroblastoma., Materials and Methods: Ninety-six children with newly diagnosed neuroblastoma were enrolled in a multicenter prospective cohort study. CT, MR, and bone scintigraphy were used to evaluate tumor stage. Sensitivity and specificity values and receiver operating characteristic (ROC) curve analyses were used to compare the accuracy of CT, MR, and scintigraphy for tumor staging., Results: Eighty-eight patients were eligible for staging analysis, and 45 patients who underwent surgery at initial diagnosis were eligible for analysis of local tumor extent. CT and MR had sensitivities of 43% and 83%, respectively (P <.01), and specificities of 97% and 88%, respectively (P >.05), for detection of stage 4 disease. Areas under the ROC curves for CT and MR were 0.81 and 0.85, respectively (P =.06); that for scintigraphy was 0.83. Addition of scintigraphy to both CT and MR increased the areas under the ROC curves to 0.90 and 0.88, respectively. Accuracy of CT and MR for staging disease confined to the chest or abdomen (stages 1, 2, and 3) was poor., Conclusion: MR alone and CT and MR combined with bone scintigraphy enable the accurate detection of stage 4 disease. Both CT and MR perform poorly for local tumor staging.

Purpose: To improve the accuracy of ventricular volume estimates and effective temporal resolution in fast cardiac acquisitions., Materials and Methods: Data sets at intermediate temporal phases were generated by means of sharing of views from two temporally adjacent data sets. A simulated model was used, and studies with patients and volunteers were conducted. View sharing was implemented in both fast gradient-echo and fast phase-contrast cine acquisitions; breath holding was used when possible., Results: Uniform repetition time (TR) radio-frequency (RF) excitation allowed a better assessment of the end-diastolic ventricular volume. In addition, view sharing provided a better estimate of end-systolic ventricular volume in cases in which rapid changes in volume occurred at or about the temporal boundary of the source images. View sharing also provided a much smoother representation of dynamic cardiac motion when viewed in a cine loop., Conclusion: View sharing and uniform TR RF excitation improve the accuracy of end-systolic and end-diastolic ventricular volume measurements by improving the effective temporal resolution.

Purpose: To assess the uptake of 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) in common and uncommon tumors in children and to develop a method for performing positron emission tomography (PET) studies in children with malignant neoplasms., Materials and Methods: Twenty-two pediatric patients with known or suspected malignancies (27 scans) underwent FDG PET. Tumor uptake of FDG was measured on PET scans., Results: Tumor uptake of FDG was detected in 17 of 21 patients with malignant disease. Neuroblastomas and their metastases (including those that did not absorb metaiodobenzylguanidine) intensely accumulated FDG. In a patient with Ewing sarcoma, FDG PET showed two foci of metastatic disease not evident on bone scans. In two patients, PET showed that large areas of the tumor were necrotic., Conclusion: FDG PET is feasible, is useful in the study of tumors in children, and may provide unique, clinically important information.

Purpose: To determine whether a lower radiation dose technique can be used for computed tomography (CT) of the pediatric pelvis without significant loss of diagnostic image quality., Materials and Methods: Thirty-six pediatric patients underwent CT at 80 mAs (experimental group), and 42 underwent CT at 240 mAs (control group). Anatomic details, image quality, and the degree of confidence in reaching a diagnosis were graded on a scale of 1 (poor) to 4 (excellent)., Results: The difference in perceived image quality between the experimental and control groups was not statistically significant. The mean scores for scans evaluated by the first reader were 3.88 for the experimental group and 3.92 for the control group (P = .2804). The mean scores for the second reader were 3.78 and 3.77 for the experimental and control groups, respectively (P = .8131)., Conclusion: A substantial dose reduction can be achieved if pelvic CT is performed at 80 mAs, without a recognizable deterioration of diagnostic image quality.

A fast gradient-recalled-echo sequence with cardiac-triggered segmented acquisition (fastcard) was compared with a standard T1-weighted spin-echo sequence with cardiac gating and respiratory compensation in the evaluation of pediatric patients with thoracic cardiovascular anomalies. Twenty patients aged 1 week to 24 years (median age, 9 months) with various abnormalities underwent magnetic resonance (MR) imaging. In 18 patients, MR imaging was performed with both gated spin-echo and fastcard. Two observers rated the clinical utility of each sequence. Fastcard images were superior to spin-echo images in 10 patients, equivalent in seven, and inferior in one. Two additional patients with suspected pulmonary vascular lesions were accurately evaluated with the fastcard technique. The fastcard technique provides superior demonstration of thoracic cardiovascular structures and turbulent flow and enables imaging in multiple phases of the cardiac cycle.

A hybrid fat-suppression sequence in magnetic resonance (MR) imaging was used to evaluate inflammatory muscle disorders in seven children: five patients with dermatomyositis, one patient with vasculitis, and one patient with viral myositis. Fat-suppressed multisection axial images obtained with the same repetition and echo times as those used to obtain standard spin-echo (SE) images enabled direct comparison of images, with little variation of T1 and T2 weighting. In six patients, the contrast on images obtained with T2 fat suppression was 15%-20% greater than contrast on conventional T2-weighted SE images. In all seven patients, the subjective judgment was that T2-weighted fat-suppression sequences improved visualization of muscle abnormalities. It is concluded that T2 fat suppression is useful in evaluation of inflammatory muscle disorders in children because it increases contrast and eliminates fat as a cause of muscle abnormality.

Concentric reduction of a dislocated hip can be evaluated by anteroposterior views or linear tomography. Anterior relationships, however, may be difficult to evaluate from a frontal radiograph despite good visibility. Computed tomography (CT), because of its cross-sectional imaging capabilities, is superior in demonstrating these relationships. The CT appearance of two types of dislocations (posterior and lateral) is described. A posterior dislocation should be suspected if the femoral metaphysis approximates the acetabulum, a mass projects behind the ischium, or the fat plane anterior to the gluteus maximus is deformed or displaced posteriorly.

The distance between the midpoint of the distal radial epiphyseal growth plate and the proximal end of the third metacarpal offers a useful measure for determining wrist size. Standards of this distance as compared to intermetacarpal width and second metacarpal length are presented. These measures (or ratios) should be useful in evaluating patients with juvenile rheumatoid arthritis and a number of congenital malformation syndromes, particularly when the carpals are still not fully ossified. Shortening of the carpus occurs in multiple epiphyseal dysplasia, the otopalatodigital syndromes, Turner syndrome, arthrogryposis, and in juvenile rheumatoid arthritis. A relatively large carpus is present in achondroplasia.

The presence of gastrointestinal (GI) tract hemangiomatosis was demonstrated by computed tomography in two children who presented with lower GI tract bleeding. Marked vascular enhancement of the bowel during rapid intravenous administration of contrast material and dynamic scanning is characteristic, similar to that seen with hemangiomas elsewhere in the body. Barium examinations demonstrate submucosal lesions within the bowel and are useful to approximate the length of bowel involvement.

Twelve children (aged 4-15 years) with suspected coarctation of the aorta or restenosis of the aorta after previous coarctation repair were considered for balloon angioplasty. Gated magnetic resonance (MR) imaging and cineangiography of the aorta were performed before angioplasty in all 12 children. In six of the nine children treated with angioplasty, MR imaging was performed between 1 day and 4 months later. Correlation with cineangiography showed that MR imaging accurately delineated the site and characteristics of the coarctation before balloon angioplasty. After balloon dilation, MR demonstrated a significant increase in the diameter of the aorta at the coarctation site in four patients and no change in two patients. No complications such as aneurysm formation, dissection, or hematoma were detected as a result of balloon angioplasty in the follow-up MR studies. A decrease in the number and size of collateral vessels was identified in successfully treated patients. MR was useful in identifying patients who were unlikely to benefit from angioplasty, determining the appropriate balloon size for angioplasty, and noninvasively monitoring patients who underwent angioplasty.

The variation in kidney length between the 1-minute radiograph (centered over the kidney) and the 5-minute study (centered over the mid-abdomen) was evaluated on 100 random excretory urograms. When both kidneys were measurable, the change in kidney size was discordant in 40%. Most such changes are due to changes in geometry, differences in centering, or changes in the angle of the kidney with respiration. These alterations are of much greater magnitude than the reported swelling of the kidney due to contrast medium. Since there is practically no relation between the time of injection and changes in renal image size, it makes no difference whether the 1-minute or 5-minute radiograph is selected for measurement.

An osseous projection from the midportion of the metaphysis of the distal phalanges of the digits was seen in 79% of untreated children with primary hypothyroidism. There is a significant difference (p less than .0005) in the incidence of this projection between children with primary hypothyroidism and those with idiopathic hypopituitarism or psychosocial dwarfism. The presence of this projection together with delayed skeletal should suggest primary hypothyroidism.