Small blue round cell tumor: an unusual case presentation in the foot

Small blue round cell tumors of childhood rarely present in the foot or ankle. The following is a case presentation of an 18-year-old male with a large soft-tissue mass of the foot with associated lung metastasis. A definitive diagnosis could not be fully made, even with immunohistochemical and genetic testing. Diagnosis favored poorly differentiated synovial sarcoma.     

Helical CT of the body: are settings adjusted for pediatric patients?

OBJECTIVE: Our objective was to determine whether adjustments related to patient age are made in the scanning parameters that are determinants of radiation dose for helical CT of pediatric patients. SUBJECTS AND METHODS: This prospective investigation included all body (chest and abdomen) helical CT examinations (n = 58) of neonates, infants, and children (n = 32) referred from outside institutions for whom radiologic consultation was requested. Information recorded included tube current, kilovoltage, collimation, and pitch. Examinations were arbitrarily grouped on the basis of the individual's age: group A, 0-4 years; group B, 5-8 years; group C, 9-12 years; and group D, 13-16 years old. RESULTS: Thirty-one percent (18/58) of the CT examinations were of the chest and 69% (40/58) were of the abdomen. Sixteen percent (9/58) of the CT examinations were combined chest and abdomen. In 22% (2/9) of these combined examinations, tube current was adjusted between the chest and abdomen CT; in one (11%) of these examinations, the tube current was higher for the chest than for the abdomen portion of the CT examination. The mean tube current setting for chest was 213 mA and was 206 mA for the abdomen, with no evident adjustment in tube current based on the age of the patient. Fifty-six percent of the examinations of neonates, infants, or children 8 years old or younger were performed at a collimation of greater than 5 mm and 53% of these examinations were performed using a pitch of 1.0. CONCLUSION: Pediatric helical CT parameters are not adjusted on the basis of the examination type or the age of the child. In particular, these results suggest that pediatric patients may be exposed to an unnecessarily high radiation dose during body CT.     

Helical CT of the body: a survey of techniques used for pediatric patients

OBJECTIVE: Our purpose was to assess the current practice of helical CT of the body in pediatric patients through a survey of members of the Society for Pediatric Radiology. MATERIALS AND METHODS: The survey consisted of 53 questions addressing demographics; oral and IV contrast media administration; and age-based (age groups, 0-4, 5-8, 9-12, and 13-16 years) scanning parameters, including tube current, kilovoltage, slice thickness, and pitch. Respondents accessed the Web-based survey via a uniform resource locator link included in an e-mail to the members of the Society for Pediatric Radiology automatically sent every week for three weeks. Survey results were automatically tabulated. RESULTS: Most (83%) respondents were based in children's or university hospitals at the time of the survey. Virtually all (99%) used nonionic IV contrast material. For body scanning, 21-32% used less than 2.0 mL/kg of body weight; we found the percentage of respondents who used power injection to be approximately equal to the percentage of those who used manual injection (47%). Age-based adjustments are made; however, 11-26% of CT examinations of children younger than 9 years are performed using more than 150 mA. A notable finding was that 20-25% of respondents did not know specific parameters used for their examinations. CONCLUSION: Although pediatric radiologists do practice age-adjusted helical CT, variable scanning techniques are used, potentially delivering high doses of radiation. Information on current practices in helical CT of the body in children can serve as a foundation for future recommendations and investigations into helical CT in pediatric patients.     

MR features of soft-tissue abnormalities due to acute marrow infarction in five children with sickle cell disease.

OBJECTIVE: The purpose of this investigation was to illustrate a variety of soft-tissue abnormalities on MR imaging encountered in connection with acute marrow infarction in children with sickle cell disease. CONCLUSION: Extraosseous abnormalities on MR imaging preclude differentiation of acute marrow infarction from osteomyelitis in children with sickle cell disease.     

Comparison of radiation dose estimates, image noise, and scan duration in pediatric body imaging for volumetric and helical modes on 320-detector CT and helical mode on 64-detector CT

Background

Advanced multidetector CT systems facilitate volumetric image acquisition, which offers theoretic dose savings over helical acquisition with shorter scan times.

Objective

Compare effective dose (ED), scan duration and image noise using 320- and 64-detector CT scanners in various acquisition modes for clinical chest, abdomen and pelvis protocols.

Materials and methods

ED and scan durations were determined for 64-detector helical, 160-detector helical and volume modes under chest, abdomen and pelvis protocols on 320-detector CT with adaptive collimation and 64-detector helical mode on 64-detector CT without adaptive collimation in a phantom representing a 5-year-old child. Noise was measured as standard deviation of Hounsfield units.

Results

Compared to 64-detector helical CT, all acquisition modes on 320-detector CT resulted in lower ED and scan durations. Dose savings were greater for chest (27–46%) than abdomen/pelvis (18–28%) and chest/abdomen/pelvis imaging (8–14%). Noise was similar across scanning modes, although some protocols on 320-detector CT produced slightly higher noise.

Conclusion

Dose savings can be achieved for chest, abdomen/pelvis and chest/abdomen/pelvis examinations on 320-detector CT compared to helical acquisition on 64-detector CT, with shorter scan durations. Although noise differences between some modes reached statistical significance, this is of doubtful diagnostic significance and will be studied further in a clinical setting.     

Minimizing radiation dose for pediatric body applications of single-detector helical CT: strategies at a large Children's Hospital

Adjustments of the standard helical CT protocols for adults can result in reduced radiation dose when imaging children. It is the radiologist's responsibility to critically evaluate the CT techniques used at their institution. Adjustments to CT protocols should be made to choose the appropriate mA and pitch when imaging children.