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Right lower quadrant (RLQ) pain is a common clinical presentation in children, and accurate clinical diagnosis remains challenging given that this nonspecific presentation is associated with numerous surgical and nonsurgical conditions. The broad differential diagnosis varies by patient age and sex. Important considerations in the selection of a diagnostic imaging strategy include the sequencing, performance, and cost of tests. This article provides a comprehensive narrative review of the diagnostic imaging of RLQ pain in children and adolescents, including a discussion of the complementary roles of ultrasound, CT, and MRI; description of key imaging findings based on available evidence; and presentation of salient differential diagnoses. Subspecialized pediatric emergency medicine and surgical perspectives are also provided as further clinical insight into this common, but often challenging, scenario. Finally, the current status of imaging of RLQ pain in children and adolescents is summarized on the basis of expert consensus.

OBJECTIVE. Diagnostic reference levels were developed as guidance for radiation dose in medical imaging and, by inference, diagnostic quality. The objective of this work was to expand the concept of diagnostic reference levels to explicitly include noise of CT examinations to simultaneously target both dose and quality through corresponding reference values. MATERIALS AND METHODS. The study consisted of 2851 adult CT examinations performed with scanners from two manufacturers and two clinical protocols: abdominopelvic CT with IV contrast administration and chest CT without IV contrast administration. An institutional informatics system was used to automatically extract protocol type, patient diameter, volume CT dose index, and noise magnitude from images. The data were divided into five reference patient size ranges. Noise reference level, noise reference range, dose reference level, and dose reference range were defined for each size range. RESULTS. The data exhibited strong dependence between dose and patient size, weak dependence between noise and patient size, and different trends for different manufacturers with differing strategies for tube current modulation. The results suggest size-based reference intervals and levels for noise and dose (e.g., noise reference level and noise reference range of 11.5-12.9 HU and 11.0-14.0 HU for chest CT and 10.1-12.1 HU and 9.4-13.7 HU for abdominopelvic CT examinations) that can be targeted to improve clinical performance consistency. CONCLUSION. New reference levels and ranges, which simultaneously consider image noise and radiation dose information across wide patient populations, were defined and determined for two clinical protocols. The methods of new quantitative constraints may provide unique and useful information about the goal of managing the variability of image quality and dose in clinical CT examinations.

Objective: Imaging registries afford opportunities to study large, heterogeneous populations. The purpose of this study was to examine the American College of Radiology CT Dose Index Registry (DIR) for dose-related demographics and metrics of common pediatric body CT examinations., Materials and Methods: Single-phase CT examinations of the abdomen and pelvis and chest submitted to the DIR over a 5-year period (July 2011-June 2016) were evaluated (head CT frequency was also collected). CT examinations were stratified into five age groups, and examination frequency was determined across age and sex. Standard dose indexes (volume CT dose index, dose-length product, and size-specific dose estimate) were categorized by body part and age. Contributions to the DIR were also categorized by region and practice type., Results: Over the study period 411,655 single-phase pediatric examinations of the abdomen and pelvis, chest, and head, constituting 5.7% of the total (adult and pediatric) examinations, were submitted to the DIR. Head CT was the most common examination across all age groups. The majority of all scan types were performed for patients in the second decade of life. Dose increased for all scan types as age increased; the dose for abdominopelvic CT was the highest in each age group. Even though the DIR was queried for single-phase examinations only, as many as 32.4% of studies contained multiple irradiation events. When these additional scans were included, the volume CT dose index for each scan type increased. Among the studies in the DIR, 99.8% came from institutions within the United States. Community practices and those that specialize in pediatrics were nearly equally represented., Conclusion: The DIR provides valuable information about practice patterns and dose trends for pediatric CT and may assist in establishing diagnostic reference levels in the pediatric population.

Objective: The purpose of this study was to develop and validate an automated method to measure noise in clinical CT examinations., Materials and Methods: An automated algorithm was developed to measure noise in CT images. To assess its validity, the global noise level was compared with image noise measured using an image subtraction technique in an anthropomorphic phantom. The global noise level was further compared with image noise values from clinical patient CT images obtained by an observer study. Finally, the clinical utility of the global noise level was shown by assessing variability of image noise across scanner models for abdominopelvic CT examinations performed in 2358 patients., Results: The global noise level agreed well with the phantom-based and clinical image-based noise measurements, with an average difference of 3.4% and 4.7% from each of these measures, respectively. No significant difference was detected between the global noise level and the validation dataset in either case. It further indicated differences across scanners, with the median global noise level varying significantly between different scanner models (15-35%)., Conclusion: The global noise level provides an accurate, robust, and automated method to measure CT noise in clinical examinations for quality assurance programs. The significant difference in noise across scanner models indicates the unexploited potential to efficiently assess and subsequently improve protocol consistency. Combined with other automated characterization of imaging performance (e.g., dose monitoring), the global noise level may offer a promising platform for the standardization and optimization of CT protocols.

Objective: The goal of this study was to implement an evidence-based teamwork system to improve communication and teamwork skills among health care professionals (TeamSTEPPS) into an academic interventional ultrasound program and to assess safety and team-work climate across team members both before and after implementation., Materials and Methods: Members of a change team (including master trainers) selected specific tools available within TeamSTEPPS to implement into an academic interventional ultrasound service. Tools selected were based on preimplementation survey data obtained from team members (n = 64: 11 attending faculty physicians, 12 clinical abdominal imaging fellows or residents, 17 sonographers, 19 nurses, and five technologist aides or administrative personnel). The survey included teamwork climate and safety climate domains from the Safety Attitudes Questionnaire. Four months after implementation, respondents were resurveyed and post-implementation data were collected., Results: Teamwork climate scores improved from a mean of 67.9 (SD, 12.8) before implementation to a mean of 87.8 (SD, 14.1) after implementation (t = -7.6; p < 0.001). Safety climate scores improved from a mean of 76.5 (SD, 12.8) before implementation to a mean of 88.3 (SD, 13.4) after implementation (t = -4.6; p < 0.001). In particular, teamwork items about "input being well received" and "speaking up" were the most responsive to the intervention., Conclusion: The implementation of TeamSTEPPS tools was associated with statistically significant improvements in safety and teamwork metrics in an academic interventional ultrasound practice. The most notable improvements were seen in communication among team members and role clarification. We think that this model, which has been successfully implemented in many nonradiologic areas in medical care, is also applicable in imaging practice.

Objective: There are limited data available on the use of i.v. contrast media for CT studies in the pediatric population. The purpose of this study is to determine the practice patterns of i.v. contrast media usage for pediatric CT by members of the Society for Pediatric Radiology (SPR)., Materials and Methods: SPR members were surveyed regarding the use of i.v. contrast media for pediatric CT studies. Questions pertained to information required before administering i.v. contrast media, types of central catheters for injecting i.v. contrast media, injection rates based on angiocatheter size and study type, and management of i.v. contrast media extravasation., Results: The response rate of 6% (88/1545) represented practice patterns of 26% (401/1545) of the SPR membership. Most respondents thought the following clinical information was mandatory before i.v. contrast media administration: allergy to i.v. contrast media (97%), renal insufficiency (97%), current metformin use (72%), significant allergies (61%), diabetes (54%), and asthma (52%). Most administered i.v. contrast media through nonimplanted central venous catheters (78%), implanted venous ports (78%), and peripherally inserted central catheters (72%). The most common maximum i.v. contrast media injection rates were 5.0 mL/s or greater for a 16-gauge angiocatheter, 4.0 mL/s for an 18-gauge angiocatheter, 3.0 mL/s for a 20-gauge angiocatheter, and 2.0 mL/s for a 22-gauge angiocatheter. For soft-tissue extravasation of i.v. contrast media, 95% elevate the affected extremity, 76% use ice, and 45% use heat., Conclusion: The results of this survey illustrate the collective opinion of a subset of SPR members relating to the use of i.v. contrast media in pediatric CT, providing guidelines for clinical histories needed before i.v. contrast media, maximum i.v. contrast injection rates for standard angiocatheters, contrast media injection rates for specific CT studies, and management of i.v. contrast media soft-tissue extravasation.

Objective: The purpose of this study was to measure the organ doses and estimate the effective dose for the standard brain perfusion CT protocol and erroneous protocols., Materials and Methods: An anthropomorphic phantom with metal oxide semiconductor field effect transistor (MOSFET) detectors was scanned on a 64-MDCT scanner. Protocol 1 used a standard brain perfusion protocol with 80 kVp and fixed tube current of 200 mA. Protocol 2 used 120 kVp and fixed tube current of 200 mA. Protocol 3 used 120 kVp with automatic tube current modulation (noise index, 2.4; minimum, 100 mA; maximum, 520 mA)., Results: Compared with protocol 1, the effective dose was 2.8 times higher with protocol 2 and 7.8 times higher with protocol 3. For all protocols, the peak dose was highest in the skin, followed by the brain and calvarial marrow. Compared with protocol 1, the peak skin dose was 2.6 times higher with protocol 2 and 6.7 times higher with protocol 3. The peak skin dose for protocol 3 exceeded 3 Gy. The ocular lens received significant scatter radiation: 177 mGy for protocol 2 and 435 mGy for protocol 3, which were 4.6 and 11.3 times the dose for protocol 1, respectively., Conclusion: Compared with the standard protocol, erroneous protocols of increasing the tube potential from 80 kVp to 120 kVp will lead to a three- to fivefold increase in organ doses, and concurrent use of high peak kilovoltage with incorrectly programmed tube current modulation can increase dose to organs by 7- to 11-fold. Tube current modulation with a low noise index can lead to doses to the skin and ocular lens that are close to thresholds for tissue reactions.

Objective: The purpose of this study was to compare CT with conventional and simulated reduced-tube current in the evaluation for acute appendicitis in children., Materials and Methods: Validated noise-addition (tube current-reduction) software was used to create 50% and 75% tube current reductions in 60 CT examinations performed for suspected appendicitis, resulting in 180 image sets. Three blinded pediatric radiologists scored the randomized studies for the following factors: presence of the normal appendix or appendicitis (5-point scale; 1=definitely absent and 5=definitely present), presence of alternate diagnoses, and overall image quality (1=nondiagnostic and 5=excellent). Truth was defined by the interpretation of the conventional examination., Results: For conventional examinations, the total number of reviews (60 cases×3 readers=180) in which the normal appendix was identified was 120 of 180 (66.7%), compared with 108 of 180 (60%) in the 50% (p=0.19) and 91 of 180 (50.6%) in the 75% (p=0.002) tube current-reduction groups. Appendicitis was identified in a total of 39 of 180 (21.7%), 38 of 180 (21.1%), and 37 of 180 (20.6%) examinations, respectively (p>0.05). This translates to sensitivities of 97% and 95% for the 50% and 75% tube current-reduction groups, respectively. Alternate diagnoses were detected in 14%, 16%, and 13% of scans, respectively. Compared with conventional-tube current examinations, reader confidence and assessment of image quality were significantly decreased for both tube current-reduction groups., Conclusion: Simulated tube current-reduction technology provides for systematic evaluation of diagnostic thresholds. Application of this technology in the setting of suspected appendicitis shows that tube current can be reduced by at least 50% without significantly affecting diagnostic quality, despite a decrease in reader confidence and assessment of image quality.

Objective: The purpose of this study is to determine patient dose estimates for clinical pediatric cardiac-gated CT angiography (CTA) protocols on a 320-MDCT volume scanner., Materials and Methods: Organ doses were measured using 20 metal oxide semiconductor field effect transistor (MOSFET) dosimeters. Radiation dose was estimated for volumetrically acquired clinical pediatric prospectively and retrospectively ECG-gated cardiac CTA protocols in 5-year-old and 1-year-old anthropomorphic phantoms on a 320-MDCT scanner. Simulated heart rates of 60 beats/min (5-year-old phantom) and 120 beats/min (1- and 5-year-old phantoms) were used. Effective doses (EDs) were calculated using average measured organ doses and International Commission on Radiological Protection 103 tissue-weighting factors. Dose-length product (DLP) was recorded for each examination and was used to develop dose conversion factors for pediatric cardiac examinations acquired with volume scan mode. DLP was also used to estimate ED according to recently published dose conversion factors for pediatric helical chest examinations. Repeated measures and paired Student t test analyses were performed., Results: For the 5-year-old phantom, at 60 beats/min, EDs ranged from 1.2 mSv for a prospectively gated examination to 4.5 mSv for a retrospectively gated examination. For the 5-year-old phantom, at 120 beats/min, EDs ranged from 3.0 mSv for a prospectively gated examination to 4.9 mSv for a retrospectively gated examination. For the 1-year-old phantom, at 120 beats/min, EDs ranged from 2.7 mSv for a prospectively gated examination to 4.5 mSv for a retrospectively gated examination., Conclusion: EDs for 320-MDCT volumetrically acquired ECG-gated pediatric cardiac CTA are lower than those published for conventional 16- and 64-MDCT scanners.

Objective: Concern about the radiation-related risks associated with medical imaging is currently a hot topic in both the scientific and lay press as well as gaining a growing awareness from regulatory and legislative organizations. As a result, there is a growing debate about whether or not we should obtain informed consent from patients--in particular, children and their parents--for examinations that expose patients to radiation. In this article, we will discuss the difficulties and challenges of informed decision making and obtaining consent for radiologic examinations., Conclusion: We provide our perspectives about the issue of whether informed consent should be required for diagnostic imaging procedures in children, although many of the points also apply to the adult population, and we discuss the dilemmas related to the process of designing and obtaining informed consent for radiologic procedures.

Objective: Diagnostic imaging performed during pregnancy, particularly if it involves the use of ionizing radiation, can be a source of great anxiety for both health care providers and patients. Especially with the growing public awareness of the increasing radiation from medical imaging, including CT, it is important to have a contemporary policy for imaging evaluation in the pregnant or potentially pregnant patient. Implementation of such policies and guidelines would be useful for those developing or modifying policies for imaging pregnant or potentially pregnant patients; those developing regional or national guidelines or recommendations (i.e., professional specialty societies, including emergency medicine, radiology, and obstetrics and gynecology); and groups such as National Council on Radiation Protection, advocacy groups, and individuals writing research grants or articles., Conclusion: To this end, a compendium of resources representing national organization guidelines would be useful. The purpose of this study is to review available resources for pertinent recommendations that can be used to develop or update policies for imaging during pregnancy, as well as to serve as a reference document for preparing reports, scientific articles, or other documents by individuals or organizations, including regulatory agencies.

Objective: The objective of our study was to determine the rate of pulmonary embolism (PE) on pulmonary CT angiography (CTA) in children and adolescents visiting adult-centered community hospitals. We also investigated alternative diagnoses that may account for presenting symptoms., Materials and Methods: We identified consecutive children and adolescents (age ≤ 19 years) who underwent pulmonary CTA during a 12- and 24-month period, respectively, at two community hospitals. Staff radiologists' clinical interpretations of pulmonary CTA studies were compared with interpretations performed by a blinded, subspecialty-trained thoracic radiologist, with a third tie-breaking interpretation performed in cases of discrepancy. A systematic review of pulmonary CTA studies for possible alternative diagnoses was completed. Diagnostic rates of PE on pulmonary CTA studies in adults at these hospitals were also reviewed for comparison., Results: The study population consisted of 130 individuals (32 boys and 98 girls; median age, 18 years; age range, 11-19 years) who underwent 137 examinations, 11 as inpatients and 126 as outpatients. CTA studies were positive for PE in six patients (4.6%). CTA showed an important alternative diagnosis, such as pulmonary consolidation, in 27 patients (21%). By comparison, pulmonary CTA studies in adults at these two hospitals yielded a 16% positive rate for PE., Conclusion: The prevalence of PE in young ambulatory patients with clinically suspected PE at adult-centered community hospitals is substantially lower than in adults. Alternative diagnoses, such as pulmonary consolidation and pneumothorax, are discovered more frequently than PE on pulmonary CTA studies. Pulmonary CTA should be used with discretion in adolescents, especially when radiography may provide the necessary diagnosis.

Objective: The objective of our study was to measure absorbed doses and calculate effective dose (ED) from cone beam CT (CBCT) with metal oxide semiconductor field effect transistor (MOSFET) detectors in an anthropomorphic phantom and to estimate the risk of cancer incidence for CBCT., Materials and Methods: Abdominal CBCT was performed in an anthropomorphic phantom of a 5-year-old child using the On-Board Imager with arbitrarily designated standard-dose (125 kVp, 80 mA, 25 milliseconds) and low-dose (125 kVp, 40 mA, 10 milliseconds) modes. The full-fan mode was used, and 20 MOSFET dosimeters were used to measure the absorbed doses in various organs. We calculated the ED, the lifetime attributable risk (LAR) for cancer incidence, and relative risk (RR) of cancer induction from a single scan for both standard- and low-dose modes in 5-year-old children., Results: The highest absorbed doses were found in the skin, ascending colon, and stomach. The mean ED was 37.8+/-0.7 (SD) mSv for the standard-dose mode and 8.1+/-0.2 mSv for the low-dose mode. The LAR of cancer incidence ranged from 23 to 144 cases per 100,000 exposed persons for the standard-dose mode and from five to 31 cases per 100,000 exposed persons for the low-dose mode. The RR of cancer incidence ranged from 1.003 to 1.054 for the standard-dose mode and from 1.001 to 1.012 for the low-dose mode., Conclusion: The ED from pediatric CBCT using the standard-dose mode was considerably higher than that of MDCT, whereas the ED for CBCT using the low-dose mode was comparable to that of abdominal MDCT. For abdominal CBCT in the pediatric phantom, the highest LARs were for colon and bladder cancers and the highest RRs were for stomach and liver cancers.

Objective: Medical physicists currently use two standardized phantoms to estimate CT patient radiation dose. This "one-size-fits-all" adult model results in underestimates of displayed pediatric CT radiation dose on the console of current CT scanners. The purpose of this article is to discuss the Alliance for Radiation Safety in Pediatric Imaging Vendor Summit., Conclusion: Stakeholders were invited to discuss the development of better estimates of pediatric patient radiation dose. These stakeholders agreed to partner to improve CT radiation dose estimates for children.

Objective: The purpose of this study was to compare the diagnostic capabilities of standard- and reduced-dose CT in the detection of nephroureterolithiasis in children., Materials and Methods: Forty-five patients 20 years old or younger divided into two groups weighing 50 kg or less and more than 50 kg underwent unenhanced 16-MDCT in the evaluation of acute flank pain. An investigational computer-simulated tube current reduction tool was used to produce additional 80- and 40-mA examination sets (total number of image sets=135). Three independent blinded readers ranked random images for stones (confidence scale, 1-5, least to most), hydronephrosis, noise-based image quality, and presence of nonrenal lesions., Results: Compared with the standard tube current used for the original CT scans, there was no significant reduction (p=0.37) in detection of renal stones at the 80-mA setting (mean dose reduction, 67%; range, 43-81%); and at the 40-mA setting (mean dose reduction, 82%; range, 72-90%), the detection rate was significantly lower (p=0.05). At the 40-mA setting, there was no significant difference among the children weighing 50 kg or less (p=0.4). Detection of ureteral stones and hydronephrosis was not significantly different at 80 and 40 mA; however, disease frequency was low, and no definite conclusion can be made., Conclusion: Simulated dose reduction is a useful tool for determining diagnostic thresholds for MDCT detection of renal stones in children. Use of the 80-mA setting for all children and 40 mA for children weighing 50 kg or less does not significantly affect the diagnosis of pediatric renal stones.

Objective: The purpose of this study was to evaluate how pediatric body MDCT scanning parameters (i.e., the principal determinants of radiation dose) have changed since a prior survey conducted in 2001., Materials and Methods: The survey used in this study consisted of 27 questions addressing practice setting; equipment; and scanning parameters including kilovoltage, tube current, and pitch. Members of the Society for Pediatric Radiology (SPR) received an email with a link to the Web-based survey. Respondents were asked to complete only one survey to represent their practice and indicate the number of pediatric radiologists their response represented., Results: Sixty-one responses representing 337 pediatric radiologists were received. Eighty-four percent of respondents practice in a university or children's hospital. No respondents reported using a peak kilovoltage setting of higher than 120 kVp for routine chest or abdomen scans. Those using 110 kVp or less increased from 4% to 48% for chest CT and from 1% to 32% for abdominal CT (p < 0.001). Weight-based adjustments in tube current are used by 98% of respondents. Tube current tends to increase with a patient's age or weight, with most pediatric body imaging examinations being performed with a tube current of less than 150 mA. The mean tube current used across all age groups decreased between 31 and 61 mA (p < 0.001), with the largest percentage decreases in patients in the 0-4 years age group., Conclusion: Since 2001, the peak kilovoltage and tube current settings, two principal parameters determining radiation dose, used by SPR members have decreased significantly for pediatric body MDCT. It is a reasonable assumption that these changes are due to efforts to increase awareness about the risks of radiation.

Objective: The purpose of our study was to assess the effect on radiation dose and image noise during pediatric chest 16-MDCT using automatic tube current modulation and bismuth breast shields., Materials and Methods: Age-based chest 16-MDCT was performed on an anthropomorphic phantom representing a 5-year-old child. Two scans were obtained in each of four sequences: first, without a shield; second, with a 2-ply bismuth shield; third, using automatic tube current modulation with a scout image obtained after placement of the shield; and fourth, using automatic tube current modulation with a scout image obtained before placement of the shield. Metal oxide semiconductor field effect transistor technology was used to measure the radiation dose in 20 organ locations. Effective dose was estimated using the console dose-length product. Noise was measured by recording the SD of Hounsfield units in identical regions of interest., Results: The bismuth breast shield reduced the dose to the breast by 26%. Shielding and automatic tube current modulation reduced the breast dose by 52%. Multiple organ doses were lowest when the shield was placed after the scout radiograph had been obtained. When the shield was placed after the scout image was obtained, the mean noise in the range of shielding increased from 11.4 to 13.1 H (superior mediastinum) and from 10.0 to 12.8 H (heart) (p < 0.01). Increased noise, however, was near the target noise index (measured in SD of Hounsfield units) of 12.0 H (SD). Using automatic tube current modulation, the effective dose was reduced by 35% when the shield was placed after the scout and by 20% when the shield was present in the scout., Conclusion: The greatest dose reduction is achieved by placing the shield after obtaining the scout image to avoid Auto mA compensation due to density of shield. With this technique, image noise increased but remained close to the target noise index.

Objective: Our purpose was to prospectively compare the reader compatibility and acceptability of a range of reduced-dose 16-MDCT images with standard-dose 16-MDCT images for the detection of nephroureterolithiasis using a dose reduction simulation technique., Subjects and Methods: The study was HIPAA compliant and institutional review board approved. Fifty consecutive patients with suspected nephrolithiasis were recruited to undergo conventional renal stone unenhanced 16-MDCT with at least 160 mA. Noise was then artificially introduced to simulate levels of 70, 100, and 130 mA. Three blinded independent readers interpreted the original and simulated-dose scans for the location and number of renal and ureteral calculi and secondary signs of obstruction using a 5-point confidence scale., Results: Reader acceptability of scans was inversely related to noise. There was no significant reduction in readers' confidence in detection or exclusion of renal collecting system calculi with simulated reduction of mA of 70, 100, and 130 compared with the standard-dose study. However, for ureteral calcifications, there was a decrease in confidence for the detection or exclusion of ureterolithiasis at an mA of 70 (35 mAs)., Conclusion: An mA as low as 70 (35 mAs) is acceptable for evaluation of nephrolithiasis. However, the evaluation of ureterolithiasis is compromised with an mA of 70.

Objective: The purpose of our study was to compare organ and effective doses for small-bowel follow-through (SBFT) and abdominopelvic MDCT in adults with Crohn's disease, to retrospectively evaluate the number of radiographic examinations performed for Crohn's disease indications, and to identify those patients undergoing serial examinations to better delineate the use of radiology in the diagnosis and clinical management of Crohn's disease., Materials and Methods: Using an anthropomorphic phantom and metal-oxide semiconductor field-effect transistor (MOSFET) dosimeters, specific organ doses were measured for 5 minutes of continuous fluoroscopy (kVp, 120; mA, 0.6) of each of the following: right lower quadrant, central abdomen, and pelvis. Effective doses were determined based on International Commission on Radiological Protection (ICRP) 60 weighting factors. Organ and effective doses were determined for abdominal and pelvic 16-MDCT: detector configuration, 16 x 0.625 mm; pitch, 1.75; 17.5 mm per rotation; rotation time, 0.5 second; 140 kVp; 340 mA. Electronic records were reviewed to determine the number of patients imaged for Crohn's disease indications and the number of studies per patient., Results: The highest fluoroscopic organ doses were as follows: in the right lower quadrant, right kidney (0.78 cGy) and marrow (0.66 cGy); in the central abdomen, kidneys (1.5 and 1.6 cGy) and marrow (0.76 cGy); and in the pelvis, marrow (0.67-0.95 cGy). Effective doses for the right lower quadrant, central abdomen, and pelvis were 1.37, 2.02, and 3.83 mSv, respectively. For MDCT, the highest organ doses were to the liver (2.95-3.33 cGy). The effective dose for abdominopelvic MDCT was 16.1 mSv. Three hundred seventy-three patients underwent imaging for Crohn's disease. The average number of SBFT and CT examinations was 1.8 and 2.3, respectively. Thirty-four (9%) of 373 patients underwent more than five CT examinations and 11 (3%) had more than 10., Conclusion: Organ and effective doses are up to five times higher with MDCT than with SBFT. Crohn's disease is more frequently imaged with CT. For a subset of patients who undergo numerous CT examinations, efforts should be made to minimize the number of CT examinations, decrease the CT dose, or consider MR enterography.

Objective: The purpose of our study was to determine a dose range for cardiac-gated CT angiography (CTA) in children., Materials and Methods: ECG-gated cardiac CTA simulating scanning of the heart was performed on an anthropomorphic phantom of a 5-year-old child on a 16-MDCT scanner using variable parameters (small field of view; 16 x 0.625 mm configuration; 0.5-second gantry cycle time; 0.275 pitch; 120 kVp at 110, 220, and 330 mA; and 80 kVp at 385 mA). Metal oxide semiconductor field effect transistor (MOSFET) technology measured 20 organ doses. Effective dose calculated using the dose-length product (DLP) was compared with effective dose determined from measured absorbed organ doses., Results: Highest organ doses included breast (3.5-12.6 cGy), lung (3.3-12.1 cGy), and bone marrow (1.7-7.6 cGy). The 80 kVp/385 mA examination produced lower radiation doses to all organs than the 120 kVp/220 mA examination. MOSFET effective doses (+/- SD) were as follows: 110 mA: 7.4 mSv (+/- 0.6 mSv), 220 mA: 17.2 mSv (+/- 0.3 mSv), 330 mA: 25.7 mSv (+/- 0.3 mSv), 80 kVp/385 mA: 10.6 mSv (+/- 0.2 mSv). DLP effective doses for diagnostic runs were as follows: 110 mA: 8.7 mSv, 220 mA: 19 mSv, 330 mA: 28 mSv, 80 kVp/385 mA: 12 mSv. DLP effective doses exceeded MOSFET effective doses by 9.7-17.2%., Conclusion: Radiation doses for a 5-year-old during cardiac-gated CTA vary greatly depending on parameters. Organ doses can be high; the effective dose may reach 28.4 mSv. Further work, including determination of size-appropriate mA and image quality, is important before routine use of this technique in children.

Objective: The purpose of our study was to measure radiation dose to the orbit during pediatric cranial CT with and without bismuth shielding using a novel dosimetry system. Cranial CT was performed on a pediatric anthropomorphic phantom, with and without bismuth eye shields. A solid-state metal oxide semiconductor field effect transistor (MOSFET) dosimeter was used to obtain real-time dose measurements., Conclusion: Bismuth shielding reduced radiation dose to the eye by up to 42%; shield artifact fell outside the diagnostic area of interest.

Objective: The purposes of this study were to apply near-real-time dose-measurement technology with metal oxide semiconductor field effect transistors (MOSFETs) to the assessment of organ dose during CT and to validate the method in comparison with the thermoluminescent dosimeter (TLD) method., Materials and Methods: Dosimetry measurements were performed in two ways, one with TLDs and the other with MOSFETs. Twenty organ locations were selected in an adult anthropomorphic female phantom. High-sensitivity MOSFET dosimeters were used. For the reference standard, TLDs were placed in the same organ locations as the MOSFETs. Both MOSFET and TLD detectors were calibrated with an X-ray beam equivalent in quality to that of a commercial CT scanner (half-value layer, approximately 7 mm Al at 120 kVp). Organ dose was determined with a scan protocol for pulmonary embolus studies on a 4-MDCT scanner., Results: Measurements for selected organ doses and the percentage difference for TLDs and MOSFETs, respectively, were as follows: thyroid (0.34 cGy, 0.31 cGy, -8%), middle lobe of lung (2.4 cGy, 3.0 cGy, +26%), bone marrow of thoracic spine (2.2 cGy, 2.5 cGy, +11%), stomach (1.0 cGy, 0.93 cGy, -6%), liver (2.5 cGy, 2.6 cGy, +6%), and left breast (3.0 cGy, 2.9 cGy, -1%). Bland-Altman analysis showed that the MOSFET results agreed with the TLD results (bias, 0.042)., Conclusion: We found good agreement between the results with the MOSFET and TLD methods. Near-real-time CT organ dose assessment not previously feasible with TLDs was achieved with MOSFETs. MOSFET technology can be used for protocol development in the rapidly changing MDCT scanner environment, in which organ dose data are extremely limited.

Objective: The objective of our study was to determine the radiation dose to the female breast from current 16-MDCT body examinations., Materials and Methods: Metal oxide semiconductor field effect transistor (MOSFET) detectors were placed in four quadrants of the breast of a female-configured anthropomorphic phantom to determine radiation dose to the breast. Imaging was performed on a 16-MDCT scanner (LightSpeed, GE Healthcare) using current clinical protocols designed to assess pulmonary embolus (PE) (140 kVp, 380 mA, 0.8-sec rotation, 16 x 1.25 mm collimation), appendicitis (140 kVp, 340 mA, 0.5-sec rotation, 16 x 0.625 mm collimation), and renal calculus (140 kVp, 160 mA, 0.5-sec rotation, 16 x 0.625 mm collimation)., Results: Radiation dose to the breast ranged from 4 to 6 cGy for the PE protocol and up to 1-2 cGy in the inferior aspect of the right breast and lateral aspect of the left breast for the appendicitis protocol. The renal calculus protocol yielded less than 150 microGy absorbed breast dose., Conclusion: Current clinical chest and abdomen protocols result in vairable radiation doses to the breast. The magnitude of exposure may have implications for imaging strategies.

Objective: The purpose of our study was to determine radiation dose to the fetus at early gestation when contemporary MDCT scanners are used for common clinical indications., Materials and Methods: Anthropomorphic phantoms were constructed to reflect a pregnant woman. Thermoluminescence dosimeters (TLDs) and metal oxide semiconductor field effect transistor (MOSFET) detectors were placed in appropriate locations to determine real-time radiation exposure to the fetus at 0 and 3 months' gestation. Imaging was performed on a 16-MDCT scanner using current institutional CT protocols: renal stone (140 kVp, 160 mA, rotation time of 0.5 sec, 16 x 0.625 mm), appendix (140 kVp, 340 mA, rotation time of 0.5 sec, 16 x 0.625 mm), and pulmonary embolus (140 kVp, 380 mA, rotation time of 0.8 sec, 16 x 1.25 mm)., Results: The radiation dose to the fetus at 0 and 3 months, respectively, was as follows: renal stone protocol, 0.8-1.2 and 0.4-0.7 cGy; appendix protocol, 1.52-1.68 and 2-4 cGy; and pulmonary embolus protocol, 0.024-0.047 and 0.061-0.066 cGy., Conclusion: Radiation doses to the fetus from institutional MDCT protocols that may be used during pregnancy (for pulmonary embolus, appendicitis, and renal colic) are below the level thought to induce neurologic detriment to the fetus. Imaging the mother for appendicitis theoretically may double the fetal risk for developing a childhood cancer. Radiation doses to the fetus from pulmonary embolus chest CT angiography are of the same magnitude as ventilation-perfusion (V/Q) scanning.

Objective: The purpose of this study was to evaluate the CT appearance, management, and temporal course of persistent pulmonary interstitial emphysema in neonates., Materials and Methods: Criteria for inclusion in the study group included neonates with a history of prematurity who required ventilation for lung disease, development of hyperexpanded radiolucent lung lesions after typical radiographic findings of pulmonary interstitial emphysema, and CT documentation of lung abnormalities. Radiographs and CT scans were reviewed for the anatomic distribution, appearance, and presence of classic lines or dots within a radiolucent mass. We compared the management (surgical vs nonsurgical) and the temporal course in nonsurgical cases for patients in the United States and patients outside the United States., Results: From seven institutions, we identified 17 patients who had persistent pulmonary interstitial emphysema with CT documentation. On CT, all lesions consisted of hyperexpanded cystic radiolucencies. Distribution was single-lobe in nine patients (left upper lobe, n = 5; left lower lobe, n = 3; right middle lobe, n = 1), multilobar in eight patients, and bilateral in six patients. Fourteen patients (82%) showed the characteristic line-and-dot pattern. All patients were initially treated conservatively; nine eventually underwent surgical resection with confirmation at pathology. Of 10 patients who underwent nonsurgical treatment for at least 1 year, lesions resolved in four patients, decreased in size in three asymptomatic patients, and enlarged in three patients, with eventual resection in two. Surgical resection was performed in 89% (8/9) of patients treated in the United States and in 13% (1/8) of patients treated outside the United States., Conclusion: Our study found that 82% of patients with persistent pulmonary interstitial emphysema had characteristic CT findings (central lines and dots surrounded by radiolucency). Although most patients in this series eventually underwent surgical resection, initial treatment can be conservative. The decision to perform surgery may have reflected the local medical culture.

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.

Objective: The purpose of our study was to evaluate the amount of radiation dose reduction and its effect on image quality when using an in-plane bismuth breast shield for multidetector CT (MDCT) of the chest and abdomen in female pediatric patients., Subjects and Methods: Fifty consecutive MDCT examinations (chest, 29; abdomen, 21) of female pediatric patients (mean age, 9 years; range, 2 months-18 years) were performed with a 2-ply (1.7 g of bismuth per square centimeter) bismuth shield (three sizes to accommodate patients of varying sizes) overlying the patient's breasts. MDCT images were evaluated for a perceptible difference in image quality in the lungs at the anatomic level under the shield as compared with nonshielded lung and whether the images were of diagnostic quality. In addition, 2-mm regions of interest were placed in the peripheral anterior and posterior portions of each lung in shielded and nonshielded areas, and noise (standard deviation in Hounsfield units) was measured in the regions. Differences among the regions in noise were compared for shielded versus nonshielded areas (paired t test). To measure differences in actual dose, we also evaluated the breast shield with an infant anthropomorphic phantom using thermoluminescent detectors in the breast tissue. The phantom was imaged with and without the breast shield using identical MDCT parameters., Results: All MDCT scans of patients were of diagnostic quality with no perceptible difference in image quality in shielded versus nonshielded lung. We found no statistically significant difference in noise between the shielded and nonshielded lung regions of interest (shielded: mean noise, 17.3 H; nonshielded: mean noise, 18.8 H; p = 0.5180). Phantom measurements revealed a 29% reduction in radiation dose to the breast when a medium-dose MDCT protocol was used., Conclusion: Bismuth in-plane breast shielding for pediatric MDCT decreased radiation dose to the breast without qualitative or quantitative changes in image quality.

Objective: Limiting CT radiation dose is especially critical when imaging children. The purpose of our study was to modify and test an accurate and safe tool for evaluating systematic dose reduction for abdominal multidetector CT (MDCT) in pediatric patients., Materials and Methods: After validating the computer-simulation technique with a water phantom, we subjected the original digital scanning data for 26 contrast-enhanced abdominal MDCT scans (120 mA) obtained in infants and children (age range, 1 month-9 years; mean age, 3.1 years) to simulated tube current reduction (100, 80, 60, and 40 mA) by adding noise. this procedure created four additional examinations per child that were identical to the originals except for image noise. The 130 examinations were scored randomly, independently, and without prior knowledge of the children's diagnoses by three radiologists for depiction of high-visibility structures, such as adrenal glands and fat in the intrahepatic falciform ligament, and low-visibility structures, such as the extrahepatic hepatic artery, small intrahepatic vessels, and common bile duct. Aligned rank and Wilcoxon's signed rank tests were used for statistical analyses., Results: Simulated tube current reduction significantly affected the detection of low-visibility structures (p < 0.001). Reduced detection in low-visibility structures was evident at a level less than or equal to 80 mA. No loss of detection in high-visibility structures was found at any tube current level (p > 0.5)., Conclusion: The results of this computer simulation suggest that accurate abdominal MDCT can be performed in pediatric patients using substantially reduced radiation, depending on the indication for imaging. (In our case, the reduction was between 33% and 67%, depending on whether a high-visibility or low-visibility structure was being assessed.) This simulation technology can be applied to MDCT of other organ systems for systematic evaluation of radiation dose reduction.

Objective: CT technique should be adjusted while scanning infants and children. One format that has proven successful in simplifying pediatric care and reducing medical error is the size-based, color-coded Broselow-Luten pediatric system. This color-coded system can serve as a format for CT protocols. The purpose of this investigation was to compare variation (or error) occurrence and technologist preference for conventional and color-coded formats for pediatric multidetector body CT protocols., Materials and Methods: Multidetector CT examinations were set up using either a conventional or a color-coded format for a period of 6 weeks each. Variations (errors) from protocol parameters (including tube current, detector configuration, table speed, and IV contrast media dose) were tabulated. Qualitative assessment consisted of a survey of CT technologists (n = 20) for preference in six areas related to ease of use and clarity of the formats., Results: There were 44 CT examinations (n = 30 infants and children) in the conventional group and 55 CT examinations (n = 31 infants and children) in the color-coded protocol format group. Overall, the number of errors was significantly less in the color-coded group (p < 0.01), with a significantly lower error percentage in individual parameters affecting radiation dose, including tube current, detector configuration, and table speed (p < 0.05). In all areas, the color-coded format was preferred over the conventional format (p < 0.0003)., Conclusion: Color-coded CT formatting is an extension of a clinical color-coded system. This system provides an easy, expeditious, consistent, and preferable format for general pediatric body CT protocols. Most importantly, the color-coded system can reduce variations (errors) in the radiology department.