Radiation dose reduction and image quality in pediatric paranasal sinus CT: with automatic tube current modulation and iterative reconstruction technique

Our objective is to evaluate radiation dose and image quality in pediatric paranasal sinus computed tomography (CT) with automatic tube current modulation (ATCM) and sinogram-affirmed iterative reconstruction algorithm (SAFIRE). CT scans from 80 patients were divided into two groups: Group A [80 kVp, pitch 1.5, 40 mAs, the filtered back projection (FBP) algorithm] and Group B (70 kVp, pitch 3, ATCM with reference at 40 mAs, SAFIRE strengths 1-5). We have evaluated image quality and radiation dose. Group B demonstrated significantly lower volume computed tomography dose index, dose-length product, and effective dose than Group A (0.13 ± 0.03 vs. 1.57 ± 0.01 mGy, 2.27 ± 0.82 vs. 19.88 ± 2.01 mGy·cm, and 0.0081 ± 0.0017 vs. 0.079 ± 0.013 mSv, respectively; P < .001). Increasing SAFIRE strengths correlated with noise reduction and SNR enhancement. Group B's noise and SNRsoft at SAFIRE strength 5 were comparable with Group A. Images reconstructed with SAFIRE strength 5 in Group B exhibit comparable image quality with FBP in Group A.

Elongated morphology of osteoid osteoma is associated with radiofrequency ablation failure in children

OBJECTIVE

To compare the frequency of elongated morphology of osteoid osteoma (OO) in children compared to adolescents and to determine if this elongated morphology is associated with radiofrequency ablation treatment failure.

MATERIALS AND METHODS

Retrospective review of first-time CT-guided radiofrequency ablation performed for presumed OO in patients < 21 years old between 1990 and 2023. Children were considered 0 to 10 years old, and adolescents were considered 11 to 20 years old. Treatment failure was considered symptomatic recurrence requiring follow-up intervention. The largest tumor dimensions in three orthogonal planes were measured using multiplanar reformatted technology. Maximum tumor dimension, tumor volume, and eccentricity index were calculated. Elongated morphology criteria were (a) largest dimension > 10 mm and (b) eccentricity index ≥ 3. Lesion locations were recorded. Statistical analyses included the chi-square test, Fisher's exact test, nonparametric Wilcoxon rank-sum test, receiver operating characteristic analysis, and Spearman's nonparametric rank correlation.

RESULTS

Of 366 included patients (median 15 years, IQR 11-18 years, 254 male), there were 86 (23.5%) children, 280 (76.5%) adolescents, and 24 (6.6%) cases of treatment failure. Elongated morphology was more common in children (19.7%) than adolescents (8.6%) (p = 0.004) and associated with younger age (p = 0.009). Elongated morphology was associated with treatment failure in children (p = 0.045) but not adolescents (p > .99) or all patients (p = 0.17). Treatment failure was not associated with age, largest dimension, eccentricity index, volume, or location.

CONCLUSION

Elongated morphology of OO is associated with younger age and radiofrequency ablation treatment failure in children. Identifying this morphology may assist with counseling and treatment planning.

Pediatric Spinal Cord Injury: A Review

A spinal cord injury (SCI) can be a devastating condition in children, with profound implications for their overall health and quality of life. In this review, we aim to provide a concise overview of the key aspects associated with SCIs in the pediatric population. Firstly, we discuss the etiology and epidemiology of SCIs in children, highlighting the diverse range of causes. We explore the unique anatomical and physiological characteristics of the developing spinal cord that contribute to the specific challenges faced by pediatric patients. Next, we delve into the clinical presentation and diagnostic methods, emphasizing the importance of prompt and accurate diagnosis to facilitate appropriate interventions. Furthermore, we approach the multidisciplinary management of pediatric SCIs, encompassing acute medical care, surgical interventions, and ongoing supportive therapies. Finally, we explore emerging research as well as innovative therapies in the field, and we emphasize the need for continued advancements in understanding and treating SCIs in children to improve their functional independence and overall quality of life.

Strategies for Managing the Risk of Mucogingival Changes During Impacted Maxillary Canine Treatment

Gingival recession is a frequent mucogingival defect in the adult population. It affects the esthetics and is related to hypersensitivity and a high risk of periodontal attachment loss. The connection between orthodontic treatment and periodontal health has been debated for a long time. A healthy periodontium can be preserved during safe orthodontic tooth movement even in patients with poor mucogingival anatomy. This article aimed to review the strategies around managing the risks of mucogingival and apical root changes owing to maxillary canine impaction, with a special focus on gingival recession and impacted maxillary canine treatment. Maxillary canines are the second most frequently impacted teeth after the third molars. They can be located in the labial or buccal aspect of the alveolar bone. If interceptive procedures fail, the next step is the challenging and time-consuming comprehensive orthodontic-surgical treatment. Determining the exact impacted canine location, its relation to the adjacent teeth and structures, the least invasive surgical approach, and the best path for traction are all a part of the standard diagnostic process. It has also been suggested that orthodontists should evaluate periodontal risks to achieve the best possible results. Clinical examination and cone beam computed tomography provide valuable information for the treatment plan that yields good results with a healthy periodontium.

Impact of iterative model reconstruction combined with dose reduction on the image quality of head and neck CTA in children

This study aimed to evaluate the imaging quality of head and neck computed tomographic angiography (CTA) in pediatric patients at a lowered radiation dose by combining an iterative model reconstruction (IMR) with low voltage scanning. Eighty-three pediatric patients were randomized into two groups as follows: Group A (n = 42), 100 kV/50 ml contrast media (CM), using filtered back projection (FBP); and Group B (n = 41), 80 kV/30 ml CM, using IMR. The enhanced CT value of the arteries, the image noise, the signal-to-noise ratio (SNR)/contrast-to-noise ratio (CNR), the image quality, the effective radiation dose (ED) and the iodine intake were compared between the two groups. The mean ED and iodine intake of group B were reduced by 69.8% and 40.0%, respectively, compared to those of group A. The mean CT values of the arteries in group B were higher than those in group A (p < 0.01), whereas the image noise of group B was lower than that of group A (p < 0.01). Group B exhibited a better image quality and a higher mean CNR/SNR than that of group A (p < 0.01). Compared to FBP, IMR in head and neck CTA enables a significant reduction in the radiation dose while preserving the diagnostic image quality. Thus, IMR, combined with low tube voltage scanning, provided an excellent solution for improving the image quality of craniocervical vessels in children.

Low-Dose CT of the Paranasal Sinuses: Minimizing X-Ray Exposure with Spectral Shaping

OBJECTIVES

Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort.

METHODS

In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192x0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 × 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures.

RESULTS

All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDI_vol 1.2 mGy vs. 4.4 mGy, p < 0.001).

CONCLUSIONS

Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure.

KEY POINTS

• Spectral optimization (tin filtration) is beneficial to low-dose parasinus CT • Tin filtration at 100 kV yields sufficient image quality for pre-operative planning • Diagnostic parasinus CT can be performed with an effective dose <0.05 mSv.

Radiation dose of cone-beam computed tomography compared to conventional radiographs in orthodontics

OBJECTIVES

The aim of this study was to determine radiation doses of different cone-beam computed tomography (CBCT) scan modes in comparison to a conventional set of orthodontic radiographs (COR) by means of phantom dosimetry.

MATERIALS AND METHODS

Thermoluminescent dosimeter (TLD) chips (3 × 1 × 1 mm) were used on an adult male tissue-equivalent phantom to record the distribution of the absorbed radiation dose. Three different scanning modes (i.e., portrait, normal landscape, and fast scan landscape) were compared to CORs [i.e., conventional lateral (LC) and posteroanterior (PA) cephalograms and digital panoramic radiograph (OPG)].

RESULTS

The following radiation levels were measured: 131.7, 91, and 77 μSv in the portrait, normal landscape, and fast landscape modes, respectively. The overall effective dose for a COR was 35.81 μSv (PA: 8.90 μSv; OPG: 21.87 μSv; LC: 5.03 μSv).

DISCUSSION

Although one CBCT scan may replace all CORs, one set of CORs still entails 2-4 times less radiation than one CBCT. Depending on the scan mode, the radiation dose of a CBCT is about 3-6 times an OPG, 8-14 times a PA, and 15-26 times a lateral LC. Finally, in order to fully reconstruct cephalograms including the cranial base and other important structures, the CBCT portrait mode must be chosen, rendering the difference in radiation exposure even clearer (131.7 vs. 35.81 μSv). Shielding radiation-sensitive organs can reduce the effective dose considerably.

CONCLUSION

CBCT should not be recommended for use in all orthodontic patients as a substitute for a conventional set of radiographs. In CBCT, reducing the height of the field of view and shielding the thyroid are advisable methods and must be implemented to lower the exposure dose.

Spine Computed Tomography Radiation Dose Reduction: Protocol Refinement Based on Measurement Variation at Simulated Lower Radiation Acquisitions

STUDY DESIGN

Retrospective dose-simulation comparison.

OBJECTIVE

To determine if sufficient detail for preoperative analysis of bony anatomy can be acquired at substantially lower doses than those typically used.

SUMMARY OF BACKGROUND DATA

Computed tomography (CT) is a preoperative planning tool for spinal surgery. The pediatric population is at risk to express the harmful effects of ionizing radiation. Preoperative CT scans are presently performed at standard pediatric radiation doses not tailored for surgical planning.

METHODS

We used the validated GE Noise Injection software to retrospectively modify existing spine and chest CT scans from 10 patients to create CT images that simulated a standard dose (100%), 50% dose, and 25% dose scans. 4 orthopedic surgeons and a pediatric radiologist, blinded to dose, measured minimum medial-lateral pedicle width and maximum anterior-posterior bony length along the axis of presumed pedicle screw placement. A total of 90 axial images were generated to create our sample set. Measurements were evaluated for accuracy, precision, and consistency.

RESULTS

For any given rater, there was no clinically relevant difference between measurements at the different dose levels and no apparent degradation in precision at the different dose levels. Consistent variation was observed between raters, the likely result of individual differences in measurement approach.

CONCLUSION

Spinal CT scans done for preoperative planning can be performed at 25% of current radiation doses without a loss in surgical planning measurement accuracy or precision. These 25% dose-reduced scans would have average Computed Tomography Dose Index volume dose levels of roughly 1.0 to 2.5 mGy (depending on patient size) and size-specific dose estimates of roughly 2.5 mGy representing a substantial dose savings compared to current practice for many sites. Standardization of consistent landmarks may be useful to further improve inter-rater concordance.

The argument for operative approach to asymptomatic lung lesions

Antenatal detection of congenital pulmonary airway malformations (CPAM) has improved immeasurably from its initial application in the 1980s and probably encompasses >80% of all such lesions. Accurate diagnosis still remains less reliable and definitive diagnosis requires detailed anatomical imaging (typically with CT scan) in the post-natal period. About 10% of all lesions will present with symptoms during the neonatal period and the choice of surgical intervention is then easy. For those that remain asymptomatic then there is still a degree of controversy about elective surgical resection. This article presents the case for elective surgery within the first year of life and aims to quantify the risks of non-intervention such as abscess, empyema, recurrent pneumonia, air-leak, and pneumothorax and various types of malignancy in such cases. The current surgical approach now includes both open muscle-sparing thoracotomy and thoracoscopic resection.

Pediatric CT dose reduction for suspected appendicitis: a practice quality improvement project using artificial gaussian noise--part 2, clinical outcomes

OBJECTIVE. The purpose of this study was to determine the effect of a nominal 50% reduction in median absorbed radiation dose on sensitivity, specificity, and negative appendectomy rate of CT for acute appendicitis in children. MATERIALS AND METHODS. On the basis of a departmental practice quality improvement initiative using computer-generated gaussian noise for CT dose reduction, we applied a nominal dose reduction of 50% to abdominal CT techniques used for bowel imaging. This retrospective study consisted of 494 children who underwent a CT for suspected acute appendicitis before (n = 244; mean age, 133 months) and after (n = 250; mean age, 145 months) the nominal 50% dose reduction. Test performance characteristics of CT for acute appendicitis and impact on the negative appendectomy rate were compared for both time periods. Primary analyses were performed with histologic diagnosis as the outcome standard. Volume CT dose index and dose-length product were recorded from dose reports and size-specific dose estimates were calculated. RESULTS. The nominal 50% dose reduction resulted in an actual 39% decrease in median absorbed radiation dose. Sensitivity of CT for diagnosis of acute appendicitis was 98% (95% CI, 91-100%) versus 97% (91-100%), and specificity was 93% (88-96%) versus 94% (90-97%) before and after dose reduction, respectively. The negative appendectomy rate was 4.5% (0.8-10.25%) before dose reduction and 4.0% (0.4-7.6%) after dose reduction. CONCLUSION. The negative appendectomy rate and performance characteristics of the CT-based diagnosis of acute appendicitis were not affected by a 39% reduction in median absorbed radiation dose.

Seventy kilovolt ultra-low dose CT of the paranasal sinus: first clinical results

AIM

To evaluate the diagnostic image quality and radiation dose of low-dose 70 kV computed tomography (CT) of the paranasal sinus in comparison to 100 and 120 kV CT.

MATERIALS AND METHODS

CT of the paranasal sinus was performed in 127 patients divided into three groups using different tube voltages and currents (70 kV/75 mAs, ultra-low dose protocol, n = 44; 100 kV/40 mAs, standard low-dose protocol, n = 42; 120 kV/40 mAs, standard protocol, n = 41). CT dose index (CTDIvol), dose-length product (DLP), attenuation, image noise and signal-to-noise ratio (SNR) were compared between the groups using Wilcoxon-Mann-Whitney U-test. Subjective diagnostic image quality was compared by using a five-point scale (1 = non-diagnostic, 5 = excellent, read by two readers in consensus) and Cohen's weighted kappa analysis for interobserver agreement.

RESULTS

Radiation dose was significantly lower with 70 kV acquisition than 100 and 120 kV (DLP: 31 versus 52 versus 82 mGy·cm; CTDI 2.33 versus 3.95 versus 6.31 mGy, all p < 0.05). Mean SNR (70 kV: 0.37; 100 kV: 0.21; 120 kV: 0.13; p < 0.05) and organ attenuation increased significantly with lower voltages. All examinations showed diagnostic image quality. Subjective diagnostic image quality was higher with standard protocols than the 70 kV protocol (120 kV: 5.0; 100 kV: 4.5; 70 kV: 3.5, p < 0.05) without significant differences with substantial interobserver agreement (κ > 0.59).

CONCLUSION

The ultra-low dose (70 kV) CT imaging of the paranasal sinus allowed for significant dose reduction by 61% and an increased attenuation of organ structures in comparison to standard acquisition while maintaining diagnostic image quality with a slight reduction in subjective image quality.

Paediatric CT optimisation utilising Catphan® 600 and age-specific anthropomorphic phantoms

The purpose of the study is to perform phantom-based optimisation of paediatric computed tomography (CT) protocols and quantify the impact upon radiation dose and image noise levels. The study involved three Portuguese paediatric centres. Currently employed scanning protocols for head and chest examinations and combinations of exposure parameters were applied to a Catphan(®)600 phantom to review the CT dose impact. Contrast-noise ratio (CNR) was quantified using Radia Diagnostic(®) tool. Imaging parameters, returning similar CNRs (<1) and dose savings were applied to three paediatric anthropomorphic phantoms. OsiriX software based on standard deviation pixel values facilitated image noise analysis. Currently employed protocols and age categorisation varied between centres. Manipulation of exposure parameters facilitated mean dose reductions of 33 and 28 % for paediatric head and chest CT examinations, respectively. The majority of the optimised CT examinations resulted in image noise similar to currently employed protocols. Dose reductions of up to 33 % were achieved with image quality maintained.

Usefulness of a lead shielding device for reducing the radiation dose to tissues outside the primary beams during CT

PURPOSE

This study was done to investigate the efficacy of a lead shield in protecting the tissues outside the primary beams, such as the breast and thyroid, by measurement of the entrance skin dose during CT of the brain, neck, abdomen, and lumbar spine.

MATERIALS AND METHODS

Institutional Review Board approval was obtained. This study included 150 patients (male:female 25:125, age range 15-45 years). In females, brain, lumbar spine, and abdominal CT scans, pre-/post-contrast neck CT scans, and post-contrast liver dynamic CT scans were performed. In males, brain CT scans only were performed. Breast shielding was performed in all females, and thyroid shielding was conducted in patients with brain CT. During all CT studies, the left breast or left thyroid was shielded using a lead shield, and the contralateral side was left unshielded. Thus, each breast or thyroid measurement had its own control for the same demographic data. The efficacy of the shielding of both breasts and thyroids during CT was assessed.

RESULTS

During brain, abdominal, lumbar, pre-/post-contrast neck, and post-contrast liver dynamic CT, 33.5, 26.0, 17.4, 26.5, and 16.2 % of the breast skin dose were reduced, respectively. During brain CT, the thyroid skin dose was reduced by 17.9 % (females) and 20.6 % (males). There were statistically significant differences in the skin doses of shielded organs (p < 0.05). Breast shielding during neck and liver dynamic CT was the most effective compared with breast or thyroid shielding during other CT scans.

CONCLUSIONS

We recommend breast shielding during neck and liver dynamic CT in young female patients to avoid unnecessary radiation exposure.

Model-based iterative reconstruction: effect on patient radiation dose and image quality in pediatric body CT

PURPOSE

To retrospectively compare image quality and radiation dose between a reduced-dose computed tomographic (CT) protocol that uses model-based iterative reconstruction (MBIR) and a standard-dose CT protocol that uses 30% adaptive statistical iterative reconstruction (ASIR) with filtered back projection.

MATERIALS AND METHODS

Institutional review board approval was obtained. Clinical CT images of the chest, abdomen, and pelvis obtained with a reduced-dose protocol were identified. Images were reconstructed with two algorithms: MBIR and 100% ASIR. All subjects had undergone standard-dose CT within the prior year, and the images were reconstructed with 30% ASIR. Reduced- and standard-dose images were evaluated objectively and subjectively. Reduced-dose images were evaluated for lesion detectability. Spatial resolution was assessed in a phantom. Radiation dose was estimated by using volumetric CT dose index (CTDI(vol)) and calculated size-specific dose estimates (SSDE). A combination of descriptive statistics, analysis of variance, and t tests was used for statistical analysis.

RESULTS

In the 25 patients who underwent the reduced-dose protocol, mean decrease in CTDI(vol) was 46% (range, 19%-65%) and mean decrease in SSDE was 44% (range, 19%-64%). Reduced-dose MBIR images had less noise (P > .004). Spatial resolution was superior for reduced-dose MBIR images. Reduced-dose MBIR images were equivalent to standard-dose images for lungs and soft tissues (P > .05) but were inferior for bones (P = .004). Reduced-dose 100% ASIR images were inferior for soft tissues (P < .002), lungs (P < .001), and bones (P < .001). By using the same reduced-dose acquisition, lesion detectability was better (38% [32 of 84 rated lesions]) or the same (62% [52 of 84 rated lesions]) with MBIR as compared with 100% ASIR.

CONCLUSION

CT performed with a reduced-dose protocol and MBIR is feasible in the pediatric population, and it maintains diagnostic quality.

The establishment of computed tomography diagnostic reference levels in Portugal

The aims of this study were to investigate the frequency of Portuguese computed tomography (CT) examinations, identify protocol application and establish diagnostic reference levels (DRLs). CT departments (n=211) were surveyed nationally (June 2011-January 2012) and CT protocol information and dose data were collected, as were retrospective age-categorised paediatric CT data from three national paediatric centres. The proposed national CT DRLs (CTDIvol) for adults were 75, 18, 14, 18, 17, 36, 22, 27 and 16 mGy for head, neck, chest, abdomen, pelvis, cervical, dorsal, lumbar and joints, respectively. The levels for paediatric head and chest examinations were as follows: 48 and 2 mGy (newborns), 50 and 6 mGy (5 y olds), 70 and 6 mGy (10 y olds) and 72 and 7 mGy (15 y olds). A limited number of current paediatric protocols aligned to recommended international age categorisations. Portuguese DRLs were generally higher than European recommendations, suggesting potential for optimisation. The need for greater standardisation of age-categorised paediatric protocols was identified.

Pediatric Hodgkin lymphoma: are we over-scanning our patients?

Despite the favorable outcome of most pediatric patients with Hodgkin lymphoma (HL), there is rising concern about risks of carcinogenesis from both diagnostic and therapeutic radiation exposure for patients treated on study protocols. Although previous studies have investigated radiation exposure during treatment, radiation from post-treatment surveillance imaging may also increase the likelihood of secondary malignancies. All diagnostic imaging examinations involving ionizing radiation exposure performed for surveillance following completion of therapy were recorded for 99 consecutive pediatric patients diagnosed with HL from 2000 to 2010. Cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. In the first 2 years following completion of therapy, patients in remission received a median of 11 examinations (range 0-26). Only 13 of 99 patients relapsed, 11 within 5 months of treatment completion. No relapse was detected by 1- or 2-view chest radiographs (n = 38 and 296, respectively), abdomen/pelvis computed tomography (CT) scans (n = 211), or positron emission tomography (PET) scans alone (n = 11). However, 10/391 (2.6%) of chest CT scans, 4/364 (1.1%) of neck CT scans, and 3/47 (6.4%) of PET/CT scans detected relapsed disease. Thus, only 17 scans (1.3%) detected relapse in a total of 1358 scans. Mean radiation dosages were 31.97 mSv for Stage 1, 37.76 mSv for Stage 2, 48.08 mSv for Stage 3, and 51.35 mSv for Stage 4 HL. Approximately 1% of surveillance imaging examinations identified relapsed disease. Given the very low rate of relapse detection by surveillance imaging stipulated by current protocols for pediatric HL patients, the financial burden of the tests themselves, the high cure rate, and risks of second malignancy from ionizing radiation exposure, modification of the surveillance strategy is recommended.

Multi-detector CT in the paediatric urinary tract

The use of paediatric multi-slice CT (MSCT) is rapidly increasing worldwide. As technology advances its application in paediatric care is constantly expanding with an increasing need for radiation dose control and appropriate utilization. Recommendations on how and when to use CT for assessment of the paediatric urinary tract appear to be an important issue. Therefore the European Society of Paediatric Radiology (ESPR) uroradiology task force and European Society of Urogenital Radiology (ESUR) paediatric working groups created a proposal for performing renal CT in children that has recently been published. The objective of this paper is to discuss paediatric urinary tract CT (uro-CT) in more detail and depth. The specific aim is not only to offer general recommendations on clinical indications and optimization processes of paediatric CT examination, but also to address various childhood characteristics and phenomena that facilitate understanding the different approach and use of uro-CT in children compared to adults. According to ALARA principles, paediatric uro-CT should only be considered for selected indications provided high-level comprehensive US is not conclusive and alternative non-ionizing techniques such as MR are not available or appropriate. Optimization of paediatric uro-CT protocols (considering lower age-adapted kV and mAs) is mandatory, and the number of phases and acquisition series should be kept as few as possible.

Ultra-low dose dual-source high-pitch computed tomography of the paranasal sinus: diagnostic sensitivity and radiation dose

BACKGROUND

Today's gold standard for diagnostic imaging of inflammatory diseases of the paranasal sinus is computed tomography (CT).

PURPOSE

To evaluate diagnostic sensitivity and radiation dose of an ultra-low dose dual-source CT technique.

MATERIAL AND METHODS

Paranasal sinuses of 14 cadaveric heads were independently evaluated by two readers using a modern dual-source CT with lowest reasonable dosage in high-pitch mode (100 kV, 10 mAs, collimation 0.6 mm, pitch value 3.0). Additionally the head part of an anthropomorphic Alderson-Rando phantom was equipped with thermoluminiscent detectors to measure radiation exposure to the eye lenses and thyroid gland.

RESULTS

Diagnostic accuracy regarding sinusoidal fluid, nasal septum deviation, and mucosal swelling was 100%. Mastoid fluid was detected in 76% and 92%, respectively. In the phantom study, average measured eye lens dosage was 0.64 mGy; radiation exposure of the thyroid gland was 0.085 mGy.

CONCLUSION

Regarding evaluation of inflammatory diseases of the paranasal sinus this study indicates sufficient accuracy of the proposed CT protocol at a very low dosage level.

Reduction of radiation exposure in pediatric patients with trauma: cephalic stabilization improves adequacy of lateral cervical spine radiographs

INTRODUCTION

Plain radiographs continue to play a role in cervical spine clearance. Inadequate radiographs commonly necessitate repeat x-rays or computed tomography imaging (10 × radiation dose). We have used the technique of cephalic stabilization (CS) to improve the results of plain radiographs. Cephalic stabilization lateral radiographs are obtained, with one assistant applying traction to the arms while another placing fingers in the patient's ears and stabilizing the head. This study tests the hypothesis that CS improves visualization of the cervicothoracic junction during lateral cervical spine radiographs.

METHODS

A 2-year review of institutional pediatric trauma registry identified 46 patients with CS, matched 1:3 with controls. Randomized lateral radiographs were evaluated independently by 2 pediatric radiologists to determine adequate visualization of the craniocervical and cervicothoracic junctions. Reviewers were blinded to CS through image cropping.

RESULTS

The proportion of adequate visualization of the cervicothoracic junction was 0.85 for cases with stabilization and 0.60 for controls. Odds of obtaining adequate visualization with stabilization are 3.8 times those without stabilization (P = .001) and were even greater for patients younger than 13 years.

CONCLUSIONS

Cephalic stabilization improves visualization of the cervicothoracic junction in lateral cervical spine radiographs and can reduce radiation exposure in patients who would otherwise require further imaging.

Long term respiratory outcomes of congenital thoracic malformations

The advent of universal antenatal ultrasonography in many countries has revealed the full spectrum of congenital thoracic malformations (CTMs) and presented clinicians with a number of practical dilemmas to do with diagnosis and management. We present a review of the most common forms of CTMs, including congenital cystic adenomatoid malformation, bronchopulmonary sequestration, and lobar and segmental emphysema.

Pulmonary embolism in pediatric patients survey of CT pulmonary angiography practices and policies

RATIONALE AND OBJECTIVES

To determine the current policies and practices of Society for Pediatric Radiology (SPR) members regarding the evaluation of pediatric patients with suspected pulmonary embolism (PE) with an emphasis on use of computed tomography pulmonary angiography (CTPA).

MATERIALS AND METHODS

Institutional review board exemption was granted for this study. Surveys were mailed electronically to the 1575 members of the SPR representing 416 institutions. Information gathered included the existence of written policies, the imaging study of choice for suspected PE, routine acquisition of chest radiographs before CTPA, currently used CTPA techniques, modifications of protocols for radiation dose reduction, typical DLP (dose-length-product) for CTPA, and estimated annual frequency of performing CTPA for evaluating PE in children. Survey items pertaining to policies and practices were compared between practice settings and populations using chi-square analysis.

RESULTS

One hundred and sixty members representing 118 institutions responded, which resulted in a response rate of 28% (118/416), on an institutional basis. Of these 118 respondents, 104 (88%) perform CTPA in children with clinical suspicion of PE. Of the 104 respondents who perform CTPA, 26 (25%) have a written policy for CTPA, 93 (89%) perform CTPA as the first study choice, and 67 (64%) routinely obtain chest radiographs before CTPA. The most commonly used CTPA techniques in children with clinical suspicion of PE include intravenous contrast amount of 2 mL/kg, mechanical injection of intravenous contrast, and tailored bolus tracking method for CTPA scan initiation by observing the Hounsfield units of contrast in the central pulmonary artery on the monitoring scan. Sixty respondents (58%) modify CTPA imaging protocols for evaluating PE in children in order to decrease radiation dose. The two most common modifications for radiation dose reduction were reduced mAs in 41 (68%) and automatic exposure control in 38 (63%). The majority of respondents (88%) did not know the typical DLP for a 20-kg child during CTPA study performed to evaluate for PE. A significantly greater percentage of radiation dose-reduction techniques are performed within academic institutions compared with private institutions (P = .03).

CONCLUSION

Most survey respondents perform CTPA as the study of choice for evaluating PE in children, but there is considerable variability in their policies and practices. Respondents from academic medical centers are more likely to employ radiation dose-reduction techniques for CTPA than those in private practice settings.

Low-dose computed tomography of the paranasal sinus and facial skull using a high-pitch dual-source system--first clinical results

OBJECTIVE

Computed tomography (CT) of the paranasal sinus is the standard diagnostic tool for a wide range of indications in mostly younger patients. This study aims to assess the image quality of CT of the sinus by using a high-pitch dual-source technique with special regard to the radiation dose.

METHODS

Examinations were performed on a second-generation dual-source CT with a pitch factor of 3.0 (dual-source mode). Images were compared with those with a pitch factor of 0.9 on the same system (single-source mode) and with those of 16-slice CT. Image quality was evaluated by four blinded readers using a 5-point scale (1=poor, 5=excellent). Comparison of the dose length product (DLP) was used to estimate radiation exposure.

RESULTS

Seventy-three consecutive patients underwent imaging with the proposed CT protocols. The viewers rated the image quality of the dual-source image sets as nearly as good (3.62) as the single-source images on the same device (4.18) and those on 16-slice CT (3.7). DLP was cut to half of the dose [51 mGycm vs. 97.8 mGycm vs. 116.9 mGycm (p<0.01)].

CONCLUSIONS

Using the proposed dual-source mode when examining the paranasal sinus, diagnostic image quality can be achieved while drastically lowering the patient's radiation exposure.

Multidetector CT in children: current concepts and dose reduction strategies

The recent technical development of multidetector CT (MDCT) has contributed to a substantial increase in its diagnostic applications and accuracy in children. A major drawback of MDCT is the use of ionising radiation with the risk of inducing secondary cancer. Therefore, justification and optimisation of paediatric MDCT is of great importance in order to minimise these risks ("as low as reasonably achievable" principle). This review will focus on all technical and non-technical aspects relevant for paediatric MDCT optimisation and includes guidelines for radiation dose level-based CT protocols.