Photon-counting computed tomography for paediatric congenital heart defects yields images of high diagnostic quality with low radiation doses at both 70 kV and 90 kV.

BACKGROUND: Photon-counting computed tomography (PCCT) is a new clinical method that may show better diagnostic quality at lower radiation doses than conventional CT. OBJECTIVE: To investigate the diagnostic quality and radiation dose of paediatric cardiovascular PCCT for diagnosis of congenital heart defects at 70 kV and 90 kV. MATERIALS AND METHODS: This retrospective assessment included clinical non-gated paediatric PCCT examinations for assessment of congenital heart defects. Radiation doses were recorded, and overall and specific diagnostic quality (1-4) were scored by four paediatric radiologists. Agreement, differences, and trends were assessed by percent rater agreement, intraclass correlation, Mann-Whitney tests, and Jonckheere-Terpstra tests. RESULTS: Seventy children with congenital heart defects were examined at 70 kV (n = 35; age 2 days-16 years; 63% boys) or 90 kV (n = 35; age 2 days-17 years; 51% boys). All observers gave a median score of 4 (high diagnostic quality) for both 70 kV and 90 kV, with no difference in median values between tube voltages (all P > 0.06). Agreement for overall scores was 66-94% for 70 kV and 60-77% for 90 kV. Agreement for specific scores was 80-97% for 70 kV and 83-89% for 90 kV. Size-dependent dose estimate was 0.68 mGy (0.25-2.02 mGy) for 70 kV and 1.10 mGy (0.58-2.71 mGy; P < 0.001) for 90 kV. Effective dose was 0.30 mSv (0.15-0.82 mSv) for 70 kV and 0.39 mSv (0.22-1.51 mSv; P = 0.01) for 90 kV. CONCLUSION: Paediatric cardiovascular PCCT yields images for congenital heart defects of high diagnostic quality with low radiation dose at both 70 kV and 90 kV.

Visualisation of the rectoanal inhibitory reflex with a modified contrast enema in children with suspected Hirschsprung disease.

BACKGROUND: Patients with Hirschsprung disease lack the normal rectoanal inhibitory reflex, which can be studied with anorectal manometry or US. OBJECTIVE: To see whether the rectoanal inhibitory reflex could be visualised with a modified contrast enema, thereby increasing the diagnostic accuracy of the contrast enema and reducing the number of rectal biopsies. MATERIALS AND METHODS: Fifty-nine boys and 42 girls (median age, 12 months) with suspected Hirschsprung disease were examined with a modified contrast enema, supplemented with two injections of cold, water-soluble contrast medium, to induce the reflex. Two paediatric radiologists evaluated the anonymised examinations in consensus. The contrast enema findings were correlated with the results of rectal biopsy or clinical follow-up. RESULTS: Five boys and one girl (median age, 7.5 days) were diagnosed with Hirschsprung disease. The negative predictive value of the rectoanal inhibitory reflex was 100%. A contrast enema with signs of Hirschsprung disease in combination with an absent rectoanal inhibitory reflex had the specificity of 98% and sensitivity of 100% for Hirschsprung disease. CONCLUSION: The modified contrast enema improves the radiological diagnosis of Hirschsprung disease. By demonstrating the rectoanal inhibitory reflex in children without Hirschsprung disease, we can reduce the proportion of unnecessary rectal biopsies.

Description and validation of a scoring system for tomosynthesis in pulmonary cystic fibrosis.

OBJECTIVES: To design and validate a scoring system for tomosynthesis (digital tomography) in pulmonary cystic fibrosis. METHODS: A scoring system dedicated to tomosynthesis in pulmonary cystic fibrosis was designed. Three radiologists independently scored 88 pairs of radiographs and tomosynthesis examinations of the chest in 60 patients with cystic fibrosis and 7 oncology patients. Radiographs were scored according to the Brasfield scoring system and tomosynthesis examinations were scored using the new scoring system. RESULTS: Observer agreements for the tomosynthesis score were almost perfect for the total score with square-weighted kappa >0.90, and generally substantial to almost perfect for subscores. Correlation between the tomosynthesis score and the Brasfield score was good for the three observers (Kendall's rank correlation tau 0.68, 0.77 and 0.78). Tomosynthesis was generally scored higher as a percentage of the maximum score. Observer agreements for the total score for Brasfield score were almost perfect (square-weighted kappa 0.80, 0.81 and 0.85). CONCLUSIONS: The tomosynthesis scoring system seems robust and correlates well with the Brasfield score. Compared with radiography, tomosynthesis is more sensitive to cystic fibrosis changes, especially bronchiectasis and mucus plugging, and the new tomosynthesis scoring system offers the possibility of more detailed and accurate scoring of disease severity. KEY POINTS: Tomosynthesis is more sensitive than conventional radiography for pulmonary cystic fibrosis changes. The radiation dose from chest tomosynthesis is low compared with computed tomography. Tomosynthesis may become useful in the regular follow-up of patients with cystic fibrosis.

Focus on the tumour periphery in MRI evaluation of soft tissue sarcoma: infiltrative growth signifies poor prognosis.

Purpose. Infiltrative microscopical peripheral growth of soft tissue sarcomas (STS) has been shown to be of prognostic importance and preoperative risk stratification could individualize neoadjuvant treatment. Patients and methods. We assessed peripheral tumour growth pattern on preoperative MRI from 78 STS. The findings were correlated to histopathology and to outcome. Results. The MRI-based peripheral tumour growth pattern was classified as pushing in 34 tumours, focally infiltrative in 25, and diffusely infiltrative in 19. All tumours with diffuse infiltration on MRI also showed microscopical infiltration, whereas MRI failed to identify infiltration in two-thirds of the microscopically infiltrative tumours. Diffusely infiltrative growth on MRI gave a 2.5 times increased risk of metastases (P = .01) and a 3.7 times higher risk of local recurrence (P = .02). Discussion. Based on this observation we suggest that MRI evaluation of STS should focus on the peripheral tumour growth pattern since it adds prognostic information of value for decisions on neoadjuvant therapies.