Dosisreduzierte 16-Schicht-Multidetektor-Spiralcomputertomographie bei Säuglingen und Kleinkindern mit bronchoskopischem Verdacht auf vaskulär bedingte Trachealstenosen - erste klinische Ergebnisse

Low Tube Voltage Chest Computed Tomography With Enhancement Using Low-Concentration Iodinated Contrast Media: Comparison of 240 mg/mL Versus 300 mg/mL Iodinated Contrast Media

Purpose: To evaluate the image quality of low voltage chest computed tomography with enhancement (CECT) using low-concentration-iodine contrast media (LCCM). Method: From 9 December to 19 December 2019, three different protocols were used for 263 patients undergoing chest CECT. Chest CECT was done using routine (300 mgI/ml contrast media with 100 kVp) protocol (group 1), LCCM (240 mgI/ml contrast media)-100 kVp protocol (group 2) and LCCM-80 kVp protocol (group 3) in 91, 97 and 75 patients, respectively. The overall diagnostic acceptability, anatomical depiction, noise and contrast-related artifacts were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and figure of merit (FOM) in the aorta and the main pulmonary trunk were measured. Results: The overall diagnostic acceptability scores were not significantly different between groups 1 and 2 (P = .261); group 3 demonstrated significantly lower overall diagnostic acceptability score compared with group 1 (P = .011) or group 2 (P < .001). However, in CECT with iterative reconstruction (IR), the overall diagnostic acceptability scores did not show significant difference among 3 groups. Group 3 showed significantly lower effective radiation dose compared with group 1 (2.33 vs 1.22 mSv, P < .001) or group 2 (2.28 vs .22 mSv, P < .001). Conclusions: In 100 kVp chest CECT, the image quality of using 240 mg/mL iodinated contrast media is comparable to that using 300 mg/mL iodine contrast media, regardless of application of IR; with IR, chest CECT using 80 kVp and 240 mg/mL iodinated contrast media results in acceptable image quality and lower radiation dose.

Tracheobronchomalacia in infants: the use of non-breath held 3D CT bronchoscopy

OBJECTIVE

To evaluate the use of a non-breath held 3D-CT-bronchoscopy in detecting tracheobronchomalacia in infants.

METHODS

The study was based on 17 infants who received both bronchoscopy and 3D-CT-bronchoscopy within 1 week at our institution. 3D-CT-bronchoscopy consisted of an axial-enhanced-chest-scan and a 3D-volume-external rendering (VR) image of the airways and was scanned with a consciously sedated non-breath held protocol, using a 64-channel-multidetecter-CT scanner. VR images were classified by two radiologists as normal, luminal narrowing or complete obliteration. All patients were confirmed with bronchoscopy and the sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) was calculated.

RESULTS

Ten (M:F¼7:3, mean 1 month) out of 17 infants were confirmed of tracheobronchomalacia. The sensitivity was <75% in detecting laryngomalacia, tracheomalacia and bronchomalacia. However, the specificity and NPV were higher than 75% for laryngomalacia, tracheomalacia and bronchomalacia and the PPV was 100% in laryngomalacia and tracheomalacia. False-positive cases included secretion plugging, extrinsic compression and foreign body, which were distinguishable in axial scans. The effective radiation dose was 0.73_0.49mSv.

CONCLUSION

A volume rendering image of the airways can be used to evaluate tracheobronchomalacia and stenosis in infants. Although, non-breath held MDCT is not recommended for screening airway lesions, narrowing of the larynx, and trachea and patency of the bronchus are reliable findings.

Paediatrician awareness of radiation dose and inherent risks in chest imaging studies--a questionnaire study

OBJECTIVE

To assess paediatricians' knowledge regarding radiation exposure of chest imaging.

MATERIALS AND METHODS

German paediatricians were surveyed using a questionnaire. Participants were asked to estimate effective dose (ED) of radiographs (CR) and computed tomography (CT). Further questions included dose-saving of paediatric CT-protocols, ALARA principle, and awareness of the link between radiation and cancer development. Length and type of occupation and amount of ordered procedures were evaluated.

RESULTS

137 paediatricians participated with 59% and 39% correctly estimating ED of an adult (0.01-0.1mSv) and newborn CR (0.01-0.1mSv), respectively. ED of an adult chest CT (1-10mSv) was underestimated by 28%, whereas ED of cardiac CT (10-100mSv) was underestimated by 54%. 35% of participants correctly estimated ED of a chest CT in an infant (10-100mSv) which was underestimated by 56%. Neither length nor type of occupation showed significant impact on dose estimations. 14% of paediatricians stated that MRI causes radiation, whereas 4% correctly estimated the potential of paediatric CT-protocols. 15% were familiar with the ALARA principle and 26% were aware of a publication concerning radiation and malignancy.

CONCLUSION

Paediatricians demonstrated an increased level of awareness compared to previous surveys. However, estimation of ED of CT remained difficult. Increased information transfer and education seem pressing in the light of increasing radiological examinations.