Quantitative diffusion-weighted magnetic resonance imaging assessment of chemotherapy treatment response of pediatric osteosarcoma and Ewing sarcoma malignant bone tumors.

OBJECTIVE: Assessment of tumor response to chemotherapy is essential in managing malignant pediatric bone tumors prior to resection. SUBJECTS AND METHODS: Pre-chemotherapy and post-chemotherapy osteosarcoma and Ewing sarcoma cases (n=18) were analyzed with apparent diffusion coefficient (ADC) values measured by two readers. RESULTS: Treated tumors demonstrated significantly greater ADC values compared to untreated tumors (p<0.001). Intraclass correlation coefficients ranged between 0.858 and 0.935. No significant tumor volume differences were observed. Regression analysis demonstrated average ADC as the best predictor of treatment. CONCLUSIONS: Our study suggests that ADC values may be useful for evaluating chemotherapeutic response of malignant pediatric bone tumors.

Imaging of physeal bars in children.

The growth plate, also known as the physis or epiphyseal plate, is essential for longitudinal growth of bones in the immature skeleton. A variety of insults to the growth plate from trauma to infection to idiopathic causes can lead to physeal bar formation, an interruption in normal growth plate cartilage, where a bony or fibrous bridge develops between the metaphysis and epiphysis. This bridge restricts subsequent bone growth, leading to limb shortening and/or angular deformities. Early recognition of the presence of a physeal bar can help direct appropriate surgical management to restore linear growth of the bone.

Aortic and hepatic contrast enhancement with abdominal 64-MDCT in pediatric patients: effect of body weight and iodine dose.

OBJECTIVE: The purpose of our study was to retrospectively evaluate the effect of body weight and iodine dose on aortic and hepatic contrast enhancement in pediatric patients who underwent 64-MDCT of the abdomen and pelvis. MATERIALS AND METHODS: Eighty-seven consecutive pediatric patients (50 boys and 37 girls; median age, 12.1 years; age range, 3.8-17.6 years) underwent standard abdominopelvic CT with a 64-MDCT scanner. Contrast medium (350 mg I/mL) was injected using a power injector at 2 mL/s followed by 15-20 mL of saline flush. According to our CT protocol, the volume of administered contrast medium was approximately 1.8 mL/kg of body weight, up to the maximum volume of 80 mL. CT scanning was initiated 60 seconds after the start of the contrast medium injection. CT attenuations of the aorta and liver were measured. For each patient, the injected contrast medium iodine mass per body weight index (g I/kg) (hereafter, iodine mass body index) was calculated. Linear regression analysis was performed between iodine mass body index and aortic and hepatic attenuations. RESULTS: A wide range of patient weights (19-82 kg; mean, 48.6 kg [95% CI, 45.3-51.9 kg]) and contrast volumes (30-80 mL; median, 80.0 mL) were observed. The median attenuations were 149.0 HU (141.0-160.0 HU) for the aorta and 113.5 HU (109.5-120.0 HU) for the liver. Moderately high correlations were observed between iodine mass body index and aortic (Spearman's rho [r(s)] = 0.60 [0.45-0.72]; p < 0.001) and hepatic (r(s) = 0.60 [0.42-0.70]; p < 0.001) attenuations. The regression formulae for aortic attenuation (58.4 + 176.3 x iodine mass body index [p < 0.001]) and hepatic attenuation (58.7 + 108.5 x iodine mass body index [p < 0.001]) indicate that 1.5 and 1.8 mL/kg (350 mg I/mL) of contrast media are required to achieve 116 and 127 HU, respectively, of contrast-enhanced attenuation in the liver. CONCLUSION: In our study, using abdominal 64-MDCT in pediatric patients, we found that approximately 1.5 mL/kg, or 0.525 g I/kg, yields 116 HU of hepatic attenuation or 50-55 HU of hepatic enhancement.

Digital mammography: a review of technical development and clinical applications.

For detecting and diagnosing breast cancer at its earliest stage, mammography is the most sensitive technique currently available and is therefore the method of choice. Screen-film mammography has been used successfully as a screening test for breast cancer for > 2 decades. However, conventional mammography has substantial limitations and, therefore, digital mammography systems have been developed to improve image quality and overcome the limitations of screen-film technique limitations. Herein we discuss the differences between screen-film and digital mammography systems and the processes related to digital mammography that differ from conventional mammography, including detector technology, digital image formation, image processing, image display, and image archival. Finally, we review the results from currently available clinical trials regarding the performance of digital mammography and discuss clinical implications such as cost-effectiveness.