Optimizing image quality for pediatric torso computed tomography: the use of advanced iterative reconstruction and wide-detector scanning techniques.

OBJECTIVES: To compare radiation exposure and image quality in children undergoing torso helical acquisition computed tomography (CT) using filtered back projection (FBP) or adaptive iterative dose reduction (AIDR) 3D reconstruction algorithms. A secondary purpose is to compare radiation exposure and image quality in children undergoing torso CT acquired with helical or wide-detector techniques reconstructed with AIDR 3D. METHODS: The study was approved by the institutional review board. Phase 1 included 200 helical torso CT studies: 100 using FBP and 100 using AIDR 3D. The size-specific dose estimate (SSDE) was calculated for each study. Region of interest (ROI) noise measurements were recorded in the thorax, abdomen, and pelvis for each study. Unpaired t tests compared SSDE and image noise for each group. Phase 2 included 100 wide-detector CT torso studies using AIDR 3D. Size-specific dose estimate and ROI noise measurements were calculated. Unpaired t tests compared helical and wide-detector SSDE and ROI. Additional t tests looked for age- and weight-specific differences in the helical and wide-detector groups. RESULTS: Phase 1: AIDR 3D showed significant reduction in SSDE (P = 0.0001) and significant improvement in image quality. Phase 2: no significant difference in SSDE was observed. Children younger than 6 years had a significant reduction in SSDE with wide-detector technique (P = 0.0445) with no loss in image quality. CONCLUSIONS: Adaptive iterative dose reduction 3D produces significant reduction in radiation dose without degradation to image quality compared with FBP. Significant dose reduction without loss of image quality can also be obtained in younger, smaller children using wide-detector technique.

Osteomyelitis of the Rib in a Child With Indolent Symptoms.

We describe a case of osteomyelitis of the rib caused by methicillin-susceptible Staphylococcus aureus. The patient presented with a subtle, indolent course leading to a suspected 2-year delay in diagnosis. This case highlights that the diagnosis of rib osteomyelitis, which can readily mimic other diagnoses, such as costochondritis, intraabdominal infections, pneumonia, or malignancies warrants a high index of suspicion. Albeit rare, pediatricians should be aware of the possibility of rib osteomyelitis in healthy children to help ensure a prompt diagnosis and appropriate, timely management.

Development and implementation of a systems-based practice project requirement for radiology residents.

RATIONALE AND OBJECTIVES: Radiology residents must now participate in a learning activity that involves identification and analysis of system errors and implementation of potential solutions. Evidence of participation must be documented in the resident's learning portfolio. MATERIALS AND METHODS: An activity based on adult learning principles was designed for residents to increase their knowledge of health care systems and problems; gain experience in writing a proposal, conducting an investigation, and reporting results; organize and present information in a supportive environment; and document participation in their portfolio. Postgraduate year 2 residents identify a systems problem. A written proposal is required and must include a "plan" that includes a hypothesis, a methods section that explains what they will "do" as an intervention, a "study" that involves collection and analysis of relevant data, and a systems change or "act." Proposals approved by the program director are presented to the radiology department. Residents complete projects, evaluate their effectiveness, and present their results by spring of postgraduate year 3. RESULTS: Goals, objectives, and guidelines were written. Assessment tools were identified. From 2006 to 2008, nine projects were proposed and conducted by 12 residents. Local and national systems issues were selected, and interventions involved residents, faculty, and medical students. A timeline was imposed to promote sustained effort. CONCLUSION: Opportunities of daily work can be used to teach and learn systems-based practice concepts. Residents can use the scientific method to test effects of change on health care systems. Relevant and practical projects enable residents to learn while improving their clinical and learning environments.

Imaging of articular disorders in children.

This article reviews aspects of arthritis imaging that are specific to children. The pediatric skeleton is unique and responds in characteristic ways to articular inflammation. Epiphyseal and physeal cartilage are affected by joint diseases, and disturbances of growth and maturation are sometimes the cardinal manifestations of arthritis. The target joints of pediatric articular diseases differ considerably from those of diseases in adults. Imaging techniques should be tailored to the children being studied.

Pontine tegmental cap dysplasia with a 2q13 microdeletion involving the NPHP1 gene: insights into malformations of the mid-hindbrain.

The case of a young man with multiple brain and somatic anomalies that presented diagnostic difficulties, is discussed in this report. A majority of his features were suggestive of Joubert syndrome--although it was felt that he did not fully meet diagnostic criteria. The subsequent evaluations included a magnetic resonance image of the brain, that was found to be consistent with pontine tegmental cap dysplasia. Chromosomal microarray studies showed a 2q13 deletion. A gene associated with Joubert syndrome, NPHP1, is within this region. This case highlights several important aspects of the diagnosis and nosology of malformations of the mid-hind brain.

Gadolinium-enhanced magnetic resonance angiography in neonates and infants suspected of caval or aortic thrombosis.

BACKGROUND: Gadolinium-enhanced magnetic resonance angiography (MRA)is a well-established technique in older children and adults. No studies have focused on its use in neonates and small infants. OBJECTIVE: Our objective was to study the use of gadolinium-enhanced MRA in neonates and infants suspected of caval or aortic thrombosis. MATERIALS AND METHODS: Gadolinium-enhanced MR angiography was performed on seven neonates and small infants for the evaluation of caval or aortic thrombosis. Gadolinium-DTPA at a dose of 0.3 mmol/kg (minimum dose 1 ml) was injected using a power injector (0.2 ml/s). Contrast-enhanced MRA was performed using a 3-D, fast, radiofrequency spoiled gradient-echo sequence (TR/TE: 4.8/1.1, flip angle 45 degrees , matrix 256 x 128, slice thickness 2.6 mm interpolated to 1.3 mm, FOV variable, NEX=1.0). RESULTS: Diagnostic-quality angiograms were obtained in all seven neonates. Superior vena cava thrombosis was identified in two neonates, and abdominal aortic thrombosis was present in one neonate. CONCLUSION: It is practical to perform gadolinium-enhanced MRA in neonates weighing as little as 600 g for the detection of caval or aortic thrombosis.