Reduced frequency of sedation of young children with multisection helical CT

Effective diameter of the abdominal aorta in children

PURPOSE

Measure out of the standard interval in the aorta diameter is a clue for aortic aneurysm or hypoplasia. Pediatric studies focusing specifically on the normal diameter of the abdominal aorta (AA) were limited in the literature. Therefore, the main goal of this work was to determine changes in the effective diameter of AA in healthy children aged 1-18 years for diagnosis of vascular diseases.

METHODS

This retrospective work focused on abdominopelvic computed tomography views of 180 children (sex: 90 males / 90 females, average age: 9.50 ± 5.20 years) without any abdominopelvic disease to measure diameters of AA, common iliac artery (CIA), external iliac artery (EIA), and first lumbar vertebra (L1).

RESULTS

Vessel and vertebra diameters increased in pediatric subjects between 1 and 18 years (p < 0.001). Considering pediatric age periods, vessel diameters increased steadily, but L1 diameter showed an irregular growth pattern between age periods. All parameters were greater in males than females (p < 0.05), except from effective diameters of AA over the coeliac trunk (p = 0.084) and over the renal artery (p = 0.051). The ratios of diameters of vessels to L1 increased depending on ages between 1 and 18 years. Considering pediatric age periods, the ratios increased from infancy period to postpubescent period in irregular pattern; however, the ratios for right and left CIA, and AA over the aortic bifurcation did not alter after late childhood period. All ratios for males were similar to females (p > 0.05).

CONCLUSION

Our age-specific ratios may be beneficial for surgeons and radiologists for the diagnosis of vascular disorders such as aortic aneurysm.

Review on Pediatric Malignant Focal Liver Lesions with Imaging Evaluation: Part I

Malignant focal liver lesions (FLLs) are commonly reported in adults but rarely seen in the pediatric population. Due to the rarity, the understanding of these diseases is still very limited. In children, most malignant FLLs are congenital. It is very important to choose appropriate imaging examination concerning various factors. This paper will outline common pediatric malignant FLLs, including hepatoblastoma, hepatocellular carcinoma, and cholangiocarcinoma and discuss them against the background of the latest knowledge on comparable/similar tumors in adults. Medical imaging features are of vital importance for the non-invasive diagnosis and follow-up of treatment of FLLs in pediatric patients. The use of CEUS in pediatric patients for characterizing those FLLs that remain indeterminate on conventional B mode ultrasounds may be an effective option in the future and has great potential to be integrated into imaging algorithms without the risk of exposure to ionizing radiation.

Impact of a Faster Computed Tomography Scanner on Sedation for Pediatric Head Computed Tomography Scans in 2 Large Emergency Departments-A Retrospective Study

OBJECTIVES

Children in the emergency department (ED) often require sedation for head computed tomography (CT) to ensure adequate image quality. Image acquisition time for a head CT using a conventional single-source CT scanner is approximately 12 seconds; however, after installation in November 2017 of 2 new dual-source dual-energy CT scanners, that time decreased to 1 to 3 seconds. We hypothesized that fewer patients would require sedation using the faster CT scanners.

METHODS

We conducted a retrospective chart review of patients aged 0 to 18 years undergoing head CT at 2 pediatric EDs within 1 hospital system, 2 years before and 2 years after installation of the faster CT scanner. Patients undergoing multiple CTs or other procedures were excluded. Demographic information, diagnosis, disposition, sedatives (chloral hydrate, dexmedetomidine, etomidate, fentanyl, ketamine, midazolam, methohexital, pentobarbital, and propofol) administered before imaging, and ED length of stay were analyzed.

RESULTS

A total of 15,175 patient encounters met inclusion criteria, 7412 before and 7763 after installation of the new CT. The median age was 7 years and 44% were female. Before the new CT scanner was installed 8% required sedation, compared with 7% after (effect size, 0.0341). Midazolam was the most commonly administered sedative. Fewer patients required deep sedation using the faster CT scanner.

CONCLUSIONS

After installation of a dual-source dual-energy CT scanner, fewer patients required sedation to complete head CT in the pediatric ED. Faster image acquisition time decreased the need for deep sedation.

Improving Quality of Chest Computed Tomography for Evaluation of Pediatric Malignancies

Introduction

Atelectasis is a problem in sedated pediatric patients undergoing cross-sectional imaging, impairing the ability to accurately interpret chest computed tomography (CT) imaging for the presence of malignancy, often leading to additional maneuvers and/or repeat imaging with additional radiation exposure.

Methods

A quality improvement team established a best-practice protocol to improve the quality of thoracic CT imaging in young patients with suspected primary or metastatic pulmonary malignancy. The specific aim was to increase the percentage of chest CT scans obtained for the evaluation of pulmonary nodules with acceptable atelectasis scores (0-1) in patients aged 0-5 years with malignancy, from a baseline of 45% to a goal of 75%.

Results

A retrospective cohort consisted of 94 patients undergoing chest CT between February 2014 and January 2015 before protocol implementation. The prospective cohort included 195 patients imaged between February 2015 and April 2018. The baseline percentage of CT scans that were scored 0 or 1 on the atelectasis scale was 44.7%, which improved to 75% with protocol implementation. The mean atelectasis score improved from 1.79 (±0.14) to 0.7 (±0.09). Sedation incidence decreased substantially from 73.2% to 26.5% during the study period.

Conclusions

Using quality improvement methodology including standardization of care, the percentage of children with atelectasis scores of 0-1 undergoing cross-sectional thoracic imaging improved from 45% to 75%. Also, eliminating the need for sedation in these patients has further improved image quality, potentially allowing for optimal detection of smaller nodules, and minimizing morbidity.

Ultrafast pediatric chest computed tomography: comparison of free-breathing vs. breath-hold imaging with and without anesthesia in young children

BACKGROUND

General anesthesia (GA) or sedation has been used to obtain good-quality motion-free breath-hold chest CT scans in young children; however pulmonary atelectasis is a common and problematic accompaniment that can confound diagnostic utility. Dual-source multidetector CT permits ultrafast high-pitch sub-second examinations, minimizing motion artifact and potentially eliminating the need for a breath-hold.

OBJECTIVE

The purpose of this study was to evaluate the feasibility of free-breathing ultrafast pediatric chest CT without GA and to compare it with breath-hold and non-breath-hold CT with GA.

MATERIALS AND METHODS

Young (≤3 years old) pediatric outpatients scheduled for chest CT under GA were recruited into the study and scanned using one of three protocols: GA with intubation, lung recruitment and breath-hold; GA without breath-hold; and free-breathing CT without anesthesia. In all three protocols an ultrafast high-pitch CT technique was used. We evaluated CT images for overall image quality, presence of atelectasis and motion artifacts.

RESULTS

We included 101 scans in the study. However the GA non-breath-hold technique was discontinued after 15 scans, when it became clear that atelectasis was a major issue despite diligent attempts to mitigate it. This technique was therefore not included in statistical evaluation (86 remaining patients). Overall image quality was higher (P=0.001) and motion artifacts were fewer (P<.001) for scans using the GA with intubation and recruitment technique compared to scans in the non-GA free-breathing group. However no significant differences were observed regarding the presence of atelectasis between these groups.

CONCLUSION

We demonstrated that although overall image quality was best and motion artifact least with a GA-breath-hold intubation and recruitment technique, free-breathing ultrafast pediatric chest CT without anesthesia provides sufficient image quality for diagnostic purposes and can be successfully performed both without and with contrast agent in young infants.

Normal abdominal aorta diameter in infants, children and adolescents

BACKGROUND

The normal limits of arterial diameters must be known to diagnose pathologies such as dilatation, stenosis and hypoplasia. Thoracic aorta diameter in childhood has been measured in previous studies, but the number of studies in which normal aortic diameter is determined is very small. The aim of this study was therefore to determine the normal standard diameter of the aorta and iliac arteries in children according to gender and level.

METHODS

Pediatric abdominal computed tomography carried out for various reasons was retrospectively re-evaluated between January 2016 and February 2017. Patients were classified according to age into six groups. Vessel diameter, age, gender and vertebra diameter were evaluated.

RESULTS

Mean proximal aorta diameter was 8.84 mm for 12-36 months, 10.02 mm for 37-84 months, 12.32 mm for 85-132 months, 14.45 mm for 133-180 months, and 16.51 mm for 181-204 months. Mean distal aorta diameter was 6.67 mm for 12-36 months, 8.07 mm for 37-84 months, 10.79 mm for 85-132 months, 12.14 mm for 133-180 months, and 14.01 mm for 181-204 months. The lumen diameter of the abdominal aorta, both proximally and distally, correlated linearly with age as an independent predictor. Similarly, the lumen diameter of the right and left common iliac artery correlated linearly with age as an independent predictor. There was no statistically significant difference in vascular diameter according to gender in any age groups.

CONCLUSIONS

Optimal evaluation of aortic diameter is possible on computed tomography. Measurement outside the normal range is a sign of aneurysm or hypoplasia.

Italian guidelines on the assessment and management of pediatric head injury in the emergency department

OBJECTIVE

We aim to formulate evidence-based recommendations to assist physicians decision-making in the assessment and management of children younger than 16 years presenting to the emergency department (ED) following a blunt head trauma with no suspicion of non-accidental injury.

METHODS

These guidelines were commissioned by the Italian Society of Pediatric Emergency Medicine and include a systematic review and analysis of the literature published since 2005. Physicians with expertise and experience in the fields of pediatrics, pediatric emergency medicine, pediatric intensive care, neurosurgery and neuroradiology, as well as an experienced pediatric nurse and a parent representative were the components of the guidelines working group. Areas of direct interest included 1) initial assessment and stabilization in the ED, 2) diagnosis of clinically important traumatic brain injury in the ED, 3) management and disposition in the ED. The guidelines do not provide specific guidance on the identification and management of possible associated cervical spine injuries. Other exclusions are noted in the full text.

CONCLUSIONS

Recommendations to guide physicians practice when assessing children presenting to the ED following blunt head trauma are reported in both summary and extensive format in the guideline document.

Patient-specific organ and effective dose estimates in pediatric oncology computed tomography

PURPOSE

Estimate organ and effective doses from computed tomography scans of pediatric oncologic patients using patient-specific information.

MATERIALS AND METHODS

With IRB approval patient-specific scan parameters and patient size obtained from DICOM images and vendor-provided dose monitoring application were obtained for a cross-sectional study of 1250 pediatric patients from 0 through 20 y-olds who underwent head, chest, abdomen-pelvis, or chest-abdomen-pelvis CT scans. Patients were categorized by age. Organ doses and effective doses were estimated using VirtualDose™ CT based on patient-specific information, tube current modulation (TCM), and age-specific realistic phantoms. CTDIvol, DLP, and dose results were compared with those reported in the literature.

RESULTS

CTDIvol and DLP varied widely as patient size varied. The 75th percentiles of CTDIvol and DLP were no greater than in the literature with the exception of head scans of 16-20 y-olds and of abdomen-pelvis scans of larger patients. Eye lens dose from a head scan was up to 69 mGy. Mean organ doses agreed with other studies at maximal difference of 38% for chest and 41% for abdomen-pelvis scans. Mean effective dose was generally higher for older patients. The highest effective doses were estimated for the 16-20 y-olds as: head 3.3 mSv, chest 4.1 mSv, abdomen-pelvis 10.0 mSv, chest-abdomen-pelvis 14.0 mSv.

CONCLUSION

Patient-specific organ and effective doses have been estimated for pediatric oncologic patients from <1 through 20 y-olds. The effect of TCM was successfully accounted for in the estimates. Output parameters varied with patient size. CTDIvol and DLP results are useful for future protocol optimization.

Multidetector computed tomographic assessment of the normal diameters for the thoracic aorta and pulmonary arteries in infants and children

BACKGROUND

Knowledge of the normal size of the thoracic aorta and pulmonary arteries is important regarding the detection of the abnormal and valuable in the treatment of patients with congenital and acquired cardiovascular diseases.

PURPOSE

To determine the normal diameters of the thoracic vascular structures of pediatric participants on contrast-enhanced multidetector computer tomography (MDCT) scans.

MATERIAL AND METHODS

Between July 2010 and July 2014, the MDCT examinations obtained from 520 participants (age range, 0-18 years; mean age, 8.49 years ± 5.54 [standard deviation]; male:female ratio, 1.6:1) with normal cardiovascular examinations were retrospectively evaluated. Patients were divided into six groups according to their age. Diameters of the ascending aorta (AA), descending aorta (DA), main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA) were measured.

RESULTS

The diameters of the thoracic vascular structures increased with age and the statistical difference among the age groups and genders were significant. The vascular structures in male patients tended to have higher dimensions than female patients. The LPA demonstrated higher mean values than the RPA in each age group. The mean ratio PA (MPA/AA) is 0.93 ± 0.08 for pediatric participants and it is slightly higher in girls compared to boys (0.93 ± 0.07 and 0.92 ± 0.07, respectively). The level of pulmonary artery bifurcation moves caudally with increasing age with thoracal 6 vertebra being the most common for all age groups (53.3%).

CONCLUSION

We believe that the results of our study can serve as a potential reference in differentiating the normal from the abnormal size of the aorta and pulmonary arteries on chest MDCT studies in the pediatric population.

Trends in CT Request and Related Outcomes in a Pediatric Emergency Department

OBJECTIVES

To study and to establish the overall trends of computed tomography (CT) use and associated outcomes in the pediatric emergency department (PED) at Royal Hospital, Oman, from 2010 to 2014.

METHODS

The hospital electronic medical record was retrospectively searched to find children (from birth to 12 years old) who had visited the PED and the number of CT requests between 1 January 2010 and 31 December 2014. The types of CT examinations ordered were analyzed according to anatomical location and were as follows; head, abdomen/pelvis, chest, cervical spine/neck, and others.

RESULTS

There were a total of 67 244 PED visits during the study period, 569 of which received 642 CT scans. There was a remarkable rise in CT uses per 1000 visits from 7 in 2010 to 12 in 2014. There was a 56% hike in CT requests from 87 in 2010 to 175 in 2014 while the number of pediatric emergency visits rose by about 28% from 11 721 to 15 052. Although head CT scans were the most common, cervical spine CT scans had the highest rate of increase (600%) followed by the chest (112%), head (54%) and abdomen (13%). There were no significant changes in other CT scan requests. The cost of CT scans increased from $18 096 to $36 400 during the study period, which increased the average PED cost by about $2 per visit. The average time between a CT being requested and then performed was 1.24 hours.

CONCLUSIONS

CT use in the pediatric emergency department has risen significantly at a rate that markedly exceeds the growth of emergency visits. This is associated with an increase in PED costs and longer waiting times.

Benign liver tumors in pediatric patients - Review with emphasis on imaging features

Benign hepatic tumors are commonly observed in adults, but rarely reported in children. The reasons for this remain speculative and the exact data concerning the incidence of these lesions are lacking. Benign hepatic tumors represent a diverse group of epithelial and mesenchymal tumors. In pediatric patients, most benign focal liver lesions are inborn and may grow like the rest of the body. Knowledge of pediatric liver diseases and their imaging appearances is essential in order to make an appropriate differential diagnosis. Selection of the appropriate imaging test is challenging, since it depends on a number of age-related factors. This paper will discuss the most frequently encountered benign liver tumors in children (infantile hepatic hemangioendothelioma, mesenchymal hamartoma, focal nodular hyperplasia, nodular regenerative hyperplasia, and hepatocellular adenoma), as well as a comparison to the current knowledge regarding such tumors in adult patients. The current emphasis is on imaging features, which are helpful not only for the initial diagnosis, but also for pre- and post-treatment evaluation and follow-up. In addition, future perspectives of contrast-enhanced ultrasound (CEUS) in pediatric patients are highlighted, with descriptions of enhancement patterns for each lesion being discussed. The role of advanced imaging tests such as CEUS and magnetic resonance imaging, which allow for non-invasive assessment of liver tumors, is of utmost importance in pediatric patients, especially when repeated imaging tests are needed and radiation exposure should be avoided.

[Aberrant right subclavian artery in children examined at the National Institute of Cardiology Ignacio Chavez (1992-2012)]

OBJECTIVES

Congenital vascular malformations of the major arteries in the chest have been classified into 5 groups: 1) double aortic arch; 2) right aortic arch with left ligament or persistent ductus arteriosus; 3) aberrant subclavian artery; 4) aberrant left pulmonary artery, and 5) anomalous innominate artery. We reviewed the patients with aberrant right subclavian artery and their treatment.

METHODS

We studied retrospectively the records of 29 patients with aberrant right subclavian artery in childhood, from January 1992 to December 2012, analyzing the following variables: age at onset, clinical manifestations, associated cardiovascular defects, diagnosis and surgical approach method.

RESULTS

We found that most patients have an asymptomatic course, only 31% of them course with symptoms during the first year of life, with an incidental diagnosis of 35% during catheterization or other imaging studies. Patent ductus arteriosus was the most frequently associated congenital malformation, with 13%. Down's syndrome was found in 21%. The most common treatment was surgical section of the aberrant subclavian artery to release the esophagus.

CONCLUSIONS

This vascular abnormality must be suspected in those patients with dysphagia, dyspnea, chest pain during feeding or breathing difficulties. A significant number of patients are not diagnosed in time, some reach adulthood without a diagnosis. This malformation is often found in imaging studies when evaluating the aorta or in a gastroesophageal reflux study, in which the barium bolus reveals the extrinsic compression of the esophagus.

Chest CT in children: anesthesia and atelectasis

BACKGROUND

There has been an increasing tendency for anesthesiologists to be responsible for providing sedation or anesthesia during chest CT imaging in young children. Anesthesia-related atelectasis noted on chest CT imaging has proven to be a common and troublesome problem, affecting image quality and diagnostic sensitivity.

OBJECTIVE

To evaluate the safety and effectiveness of a standardized anesthesia, lung recruitment, controlled-ventilation technique developed at our institution to prevent atelectasis for chest CT imaging in young children.

MATERIALS AND METHODS

Fifty-six chest CT scans were obtained in 42 children using a research-based intubation, lung recruitment and controlled-ventilation CT scanning protocol. These studies were compared with 70 non-protocolized chest CT scans under anesthesia taken from 18 of the same children, who were tested at different times, without the specific lung recruitment and controlled-ventilation technique. Two radiology readers scored all inspiratory chest CT scans for overall CT quality and atelectasis. Detailed cardiorespiratory parameters were evaluated at baseline, and during recruitment and inspiratory imaging on 21 controlled-ventilation cases and 8 control cases.

RESULTS

Significant differences were noted between groups for both quality and atelectasis scores with optimal scoring demonstrated in the controlled-ventilation cases where 70% were rated very good to excellent quality scans compared with only 24% of non-protocol cases. There was no or minimal atelectasis in 48% of the controlled ventilation cases compared to 51% of non-protocol cases with segmental, multisegmental or lobar atelectasis present. No significant difference in cardiorespiratory parameters was found between controlled ventilation and other chest CT cases and no procedure-related adverse events occurred.

CONCLUSION

Controlled-ventilation infant CT scanning under general anesthesia, utilizing intubation and recruitment maneuvers followed by chest CT scans, appears to be a safe and effective method to obtain reliable and reproducible high-quality, motion-free chest CT images in children.

Computed tomography: important considerations for pediatric patients

Computed tomography plays a central and increasingly important role in medical imaging. From the very beginning more than 30 years ago, computed tomography technology has continued to develop and provide a wide variety of applications for evaluation of disorders of virtually any organ system in both children and adults. The benefits are particularly evident with the newer, fast, high-resolution multidetector scanners. However, these benefits must be carefully weighed against the potential risks, which include a relatively high radiation dose. Current research efforts are directed at both further improvements in the diagnostic potential with computed tomography, as well as managing radiation dose.

Pharmacological sedation for cranial computed tomography in children after minor blunt head trauma

OBJECTIVE

Children evaluated in emergency departments for blunt head trauma (BHT) frequently undergo computed tomography (CT), with some requiring pharmacological sedation. Cranial CT sedation complications are understudied. The objective of this study was to document the frequency, type, and complications of pharmacological sedation for cranial CT in children.

METHODS

We prospectively enrolled children (younger than 18 years) with minor BHT presenting to 25 emergency departments from 2004 to 2006. Data collected included sedation agent and complications. We excluded patients with Glasgow Coma Scale scores of less than 14.

RESULTS

Of 57,030 eligible patients, 43,904 (77%) were enrolled in the parent study; 15,176 (35%) had CT scans performed or planned, and 527 (3%) received pharmacological sedation for CT. Sedated patients' characteristics were as follows: median age, 1.7 years (interquartile range, 1.1-2.5 years); male 61%; Glasgow Coma Scale score of 15, 86%; traumatic brain injury on CT, 8%. There were 488 patients (93%) who received 1 sedative. Sedation use (0%-21%) and regimen varied by site. Pentobarbital (n = 164) and chloral hydrate (n = 149) were the most frequently used agents. Sedation complications occurred in 49 patients (9%; 95% confidence interval [CI], 7%-12%): laryngospasm 1 (0.2%; 95% CI, 0%-1.1%), failed sedation 31 (6%; 95% CI, 4%-8%), vomiting 6 (1%; 95% CI, 0.4%-2%), hypotension 13 (4%; 95% CI, 2%-7%), and hypoxia 1 (0.2%; 95% CI, 0%-2%). No cases of apnea, aspiration, or reversal agent use occurred. One patient required intubation. Vomiting and failed sedation were most common with chloral hydrate.

CONCLUSIONS

Pharmacological sedation is infrequently used for children with minor BHT undergoing CT, and complications are uncommon. The variability in sedation medications and frequency suggests a need for evidence-based guidelines.

Advanced large airway CT imaging in children: evolution from axial to 4-D assessment

Continuing advances in multidetector computed tomography (MDCT) technology are revolutionizing the non-invasive evaluation of congenital and acquired large airway disorders in children. For example, the faster scanning time and increased anatomical coverage that are afforded by MDCT are especially beneficial to children. MDCT also provides high-quality multiplanar 2-dimensional (2-D), internal and external volume-rendering 3-dimensional (3-D), and dynamic 4-dimensional (4-D) imaging. These advances have enabled CT to become the primary non-invasive imaging modality of choice for the diagnosis, treatment planning, and follow-up evaluation of various large airway disorders in infants and children. It is thus essential for radiologists to be familiar with safe and effective techniques for performing MDCT and to be able to recognize the characteristic imaging appearances of large airway disorders affecting children.

Targeted MRI contrast agents for pediatric hepatobiliary disease

New options are available for the magnetic resonance imaging (MRI) assessment of pediatric hepatobiliary disease. This article describes the potential utility for MRI with contrast agents tailored for hepatobiliary imaging. MRI contrast agents that preferentially target the liver may be helpful in characterizing liver masses and bile duct abnormalities in select children. The imaging approach is noninvasive and relatively rapid to perform. It also provides anatomic and functional information and is a radiation-free alternative to other imaging strategies. This relatively new imaging procedure is placed in the context of more established imaging modalities. The pharmacokinetics, technical considerations, and potential applications of these hepatobiliary-specific contrast agents also are discussed.

Rising use of CT in child visits to the emergency department in the United States, 1995-2008

PURPOSE

To describe nationwide trends and factors associated with the use of computed tomography (CT) in children visiting emergency departments (EDs) in the United States between 1995 and 2008.

MATERIALS AND METHODS

This study was exempt from institutional review board oversight. Data from the 1995-2008 National Hospital Ambulatory Medical Care Survey were used to evaluate the number and percentage of visits associated with CT for patients younger than 18 years. A mean of 7375 visits were sampled each year. Data were subcategorized according to multiple patient and hospital characteristics. The Rao-Scott χ(2) test was performed to determine whether CT use was similar across subpopulations.

RESULTS

From 1995 to 2008, the number of pediatric ED visits that included CT examination increased from 0.33 to 1.65 million, a fivefold increase, with a compound annual growth rate of 13.2%. The percentage of visits associated with CT increased from 1.2% to 5.9%, a 4.8-fold increase, with a compound annual growth rate of 12.8%. The number of visits associated with CT at pediatric-focused and non-pediatric-focused EDs increased from 14,895 and 316,133, respectively, in 1995 to 212,716 and 1,438,413, respectively, in 2008. By the end of the study period, top chief complaints among those undergoing CT included head injury, abdominal pain, and headache.

CONCLUSION

Use of CT in children who visit the ED has increased substantially and occurs primarily at non-pediatric-focused facilities. This underscores the need for special attention to this vulnerable population to ensure that imaging is appropriately ordered, performed, and interpreted.

Retroperitoneal neoplasms within the perirenal space in infants and children: differentiation of renal and non-renal origin in enhanced CT images

PURPOSE

To retrospectively demonstrate the specific CT findings of retroperitoneal neoplasms to diagnosis and differential diagnosis renal and non-renal tumors within the perirenal space in infants and children.

MATERIALS AND METHODS

We retrospectively reviewed the clinical data and CT images of 42 consecutive patients with surgically and pathologically proven retroperitoneal neoplasms within the perirenal space. The patients were divided into renal tumors group (n=16) and non-renal tumors group (n=26). The former included nephroblastoma (n=15) and renal lymphoma (n=1), while the latter included neuroblastoma (n=12), retroperitoneal teratoma (n=6), adrenal ganglioneuroma (n=4), retroperitoneal lymphoma (n=2), ectopic pheochromocytoma (n=1) and adrenal cortical carcinoma (n=1). The clinical information of these patients and the major CT imaging findings which were related to lesion localization in the two groups were compared and statistically analyzed using Pearson Chi-Square Test and Risk Estimate.

RESULTS

The mean diameter of tumors was 9.82±6.13 cm (n=42 range: 2.3-3 2cm). The demographic data and chief clinical symptoms between the renal tumor group and the non-renal tumor group showed no statistically significant differences (P>0.05). 30.8% (8/26) of non-renal tumor patients presented elevated urinary vanillylmandelic acid (VMA) level, while no patient showed elevated VMA in renal tumor group (P<0.05). Some CT imaging signs of the renal tumors including "crescent sign" (odds ratio, OR=52), "beak sign" (OR=84), "embedded organ sign" (OR=84), and "prominent feeding artery sign" (OR=36) showed significantly higher incidence when compared to the non-renal tumors (P<0.001). The sign of "renal displacement and renal axis rotation" (OR=0.059) was seen in 23 of 26 (88.5%) non-renal tumors, but in only 5 of 16 (31.3%) renal tumors (P<0.001). The sign of "extra-renal central plane of tumor" (OR=0.038) was displayed in 24 of 26 (92.3%) non-renal tumors, but in only 5 of 16 (31.3%) renal tumors (P<0.001). The CT findings such as "pseudocapsule" (OR=38.5), "necrosis and cystic change" (OR=11.2), "vascularity" (OR=16.867), "distant metastasis" (OR=5.96), and "inferior vena cava tumor thrombus" which were thought to be characteristic of renal tumors were observed with significant higher incidence in renal tumors group than in the non-renal tumors group (P<0.05); while CT signs of "irregular mass" (OR=0.045) and "intratumoral calcifications" (OR=0.065) were observed with lower incidence in renal tumors group than in the non-renal tumors group (P<0.05).

CONCLUSION

The "crescent sign", "beak sign", "embedded kidney sign" and "renal arteries feeding" are the most specific CT signs suggestive of renal tumors and distinguish them from non-renal origin tumors within the perirenal space. Other CT signs, such as "pseudocapsule", "hypervascular tumors" and "Inferior vena cava tumor thrombus", when present, tumors of renal origin are strongly suggested. On the other hand, CT signs of "irregular mass", "intratumoral calcifications", and associated elevated urinary vanillylmandelic acid strongly suggest the non-renal tumors.

Etomidate versus pentobarbital for computed tomography sedations: report from the Pediatric Sedation Research Consortium

OBJECTIVE

To compare efficacy, sedation duration, and adverse events after administration of etomidate or pentobarbital for diagnostic computed tomography (CT) scans.

METHODS

A cohort of children sedated for CT scans between July 2004 and October 2005 was identified from a prospectively generated Pediatric Sedation Research Consortium database. The 24 Pediatric Sedation Research Consortium institutions prospectively record consecutive sedation data and adverse events on a Web-based tool. This study included all patients of American Society for Anesthesiologists (ASA) class I or II, between 6 months and 6 years old, sedated with etomidate or with intravenous pentobarbital with or without midazolam. Outcomes included sedation efficacy, duration (time from drug administration until cessation of monitoring), and complication rate.

RESULTS

Of 3397 pediatric sedations for CT scans, 2587 met age and ASA criteria. Etomidate was administered by pediatric emergency physicians as the sole sedative for 446 sedation service cases; pentobarbital with or without midazolam was used in 396 sedations by a variety of providers. Sedation was "not ideal" for 11 pentobarbital sedations and 1 etomidate sedation. Median etomidate dose was 0.33 mg/kg (intraquartile rank, 0.30-0.44 mg/kg); median pentobarbital dose was 4 mg/kg (intraquartile rank, 3.2-4.8 mg/kg). Mean etomidate sedation (34 minutes; 95% confidence interval [CI], 32-36 minutes) was shorter than pentobarbital (144 minutes; 95% CI, 139-150 minutes). Etomidate patients were younger (24 vs. 29 months), whereas pentobarbital patients were more often of ASA class II (52% vs. 34%), both P < 0.001. Adverse events were more common with pentobarbital (4.5% vs. 0.9%; relative risk, 3.38%; 95% CI, 1.28%-9.45%). One etomidate and 2 pentobarbital patients experienced apnea.

CONCLUSIONS

Etomidate as given by emergency physicians was more effective and efficient than pentobarbital, with rare adverse events.

Informing parents about CT radiation exposure in children: it's OK to tell them

OBJECTIVE

The purpose of our study was to determine how parents' understanding of and willingness to allow their children to undergo CT change after receiving information regarding radiation dose and risk.

MATERIALS AND METHODS

One hundred parents of children undergoing nonemergent CT studies at a tertiary-care children's hospital were surveyed before and after reading an informational handout describing radiation risk. Parental knowledge of whether CT uses radiation or increases lifetime risk of cancer was assessed, as was willingness to permit their child to undergo both a CT examination that their child's doctor recommended and one for which their doctor thought observation might be equally effective.

RESULTS

Of the 100 parents who were surveyed, 66% believed CT uses radiation before reading the handout, versus 99% afterward (p < 0.01). Before reading the handout, 13% believed CT increases the lifetime risk of cancer, versus 86% afterward (p < 0.01). After reading the handout, parents became less willing to have their child undergo CT given a hypothetic situation in which their doctor believed that either CT or observation would be equally effective (p < 0.01), but their willingness to have their child undergo CT recommended by their doctor did not significantly change. After reading the handout, 62% of parents reported no change in level of concern. No parent refused or requested to defer CT after reading the handout.

CONCLUSION

A brief informational handout can improve parental understanding of the potential increased risk of cancer related to pediatric CT without causing parents to refuse studies recommended by the referring physician.

Paediatric anaesthesia outside the operating room

Anaesthesiologists are regularly consulted to provide anaesthesia for children in settings other than an operating room. Current debate focuses on the appropriateness of the presence of an anaesthesiologist versus a non-anaesthesiologist. There is mounting evidence that the presence of an anaesthesiologist is safer. We will review the recent literature concerning paediatric anaesthesia outside the operating room and offer recommendations that may impact on efficacy and safety.

Low dose of rectal thiopental sodium for pediatric sedation in spiral computed tomography study

BACKGROUND

The aim of this study was to determine the effectiveness of reduced new dose in rectal sedation by thiopental sodium for computed tomography (CT) diagnostic imaging.

METHODS

A total of 90 children (mean age, 24.21 month +/- 13.63 [standard deviation]) underwent spiral CT study after rectal administration of thiopental sodium injection solution. The new dose ranged from 15 to 25 mg/kg with a total dose of 350 mg. The percentage of success and adverse reaction were evaluated.

RESULTS

Sedation was successful in 98% of infants and children with an average time of 8.04 min +/- 6.87 (standard deviation). One of the cases found desaturation, two experienced vomiting, 14 found rectal defecation, and two experienced hyperactivity. No prolonged sedation was observed.

CONCLUSION

Rectal administration of thiopental sodium for pediatric CT imaging is safe and effective even for hyperextend position by new reduced dose of the drug. This procedure could be easily done in the CT department under supervision of the radiologist.

Tracheobronchial Anomalies and Stenoses: Detection with Low-Dose Multidetector CT with Virtual Tracheobronchoscopy—Comparison with Flexible Tracheobronchoscopy

PURPOSE

To prospectively assess the sensitivity and specificity of low-dose multidetector computed tomography (CT) with virtual tracheobronchoscopy (VT) for evaluation of suspected airway stenoses and/or abnormalities by using flexible tracheobronchoscopy (FT) as the reference standard.

MATERIALS AND METHODS

The study was approved by the local ethics committee; parental consent was obtained. Forty-five patients with clinically and/or radiographically suspected tracheobronchial stenosis and/or anomaly underwent FT and contrast material-enhanced single-phase multidetector CT with VT. CT was performed with an age- and weight-adjusted low-dose protocol: 120 or 80 kV; 120 or 60 mA; collimation, 1.5 or 0.75 mm; gantry rotation, 0.5 second. Mean effective dose was calculated for all examinations. Postprocessing was performed with surface rendering of VT images and multiplanar reformations. CT images were analyzed in consensus by two radiologists who were blinded to FT results. Statistical analysis was performed with 2 x 2 contingency tables; 95% confidence intervals (CIs) were calculated with the Blyth-Still-Casella procedure.

RESULTS

Mean patient age was 4.4 years (range, 2 months to 16 years; 53% male patients). Tracheobronchial narrowing and/or abnormality were depicted at FT in 38 of 45 patients. In 33 of 38 patients, multidetector CT with VT depicted a tracheobronchial narrowing and/or anomaly. In 10 of 38 patients, tracheobronchial stenosis was induced by vascular anomalies. Five patients with normal findings at multidetector CT with VT had tracheobronchomalacia with inspiratory airway stenosis at FT. Sensitivity and specificity of CT with VT were 86.8% (95% CI: 73.3%, 94.7%) and 85.7% (95% CI: 44.6%, 99.3%), respectively. Positive and negative predictive values were 97.1% (95% CI: 84.9%, 99.9%) and 54.5% (95% CI: 25.0%, 80.0%), respectively. Overall accuracy was 86.7% (95% CI: 74.3%, 94.0%). Mean effective dose was 1.1 mSv (range, 0.5-1.8 mSv).

CONCLUSION

Multidetector CT with VT with a low-dose protocol had high sensitivity and specificity for depiction of tracheobronchial narrowings and/or anomalies. However, tracheal narrowing due to tracheobronchomalacia was difficult to diagnose at single-phase multidetector CT with VT.

3D multidetector CT angiographic evaluation of extralobar pulmonary sequestration with anomalous venous drainage into the left internal mammary vein in a paediatric patient

Pulmonary sequestration is a congenital lung malformation, defined by dysplastic and non-functioning lung tissue lacking normal tracheobronchial connections and accompanied by an anomalous systemic blood supply. Recognition of anomalous arteries and veins in pulmonary sequestration is paramount to making the correct diagnosis. In contrast to intralobar pulmonary sequestration, where anomalous venous drainage is usually into the pulmonary venous system, the pattern of anomalous venous drainage is more varied in extralobar pulmonary sequestration. To the best of our knowledge, anomalous venous drainage to the internal mammary vein in extralobar sequestrations has not been reported. We report an anomalous venous drainage into the internal mammary vein in an extralobar sequestration which was evaluated with 3D multidetector CT angiography.

The utilization of pediatric computed tomography in a large Israeli Health Maintenance Organization

BACKGROUND

Concern has been raised about the potential risks related to radiation exposure from CT scans, particularly among children. However, to date, there are few data available describing the magnitude of pediatric CT utilization.

OBJECTIVE

The aim of the study was to explore patterns of CT use in pediatric patients, with respect to time, use of multiple scans, body regions imaged, and medical diagnoses.

MATERIALS AND METHODS

Records of 22,223 scans performed on 18,075 people aged < or =18 years over the period 1999-2003, including diagnoses recorded within 21 days after the examination, were obtained from a large Israeli Health Maintenance Organization (1,600,000 members).

RESULTS

The highest annual CT examination rate (per 1,000) was recorded in 2001 (10.1) compared to 7.0 and 6.3 in 1999 and 2003, respectively. The lowest rate (three scans per 1,000) was found for 3-year-old children, with increasing rates with age. The head was the most frequently scanned region, both in young children (78%) and adolescents (39%). Symptoms of ill-defined conditions and injuries were documented in 22% and 10% of all scans, respectively.

CONCLUSIONS

Although the results suggest that children comprise only 3% of all patients undergoing CT, this important modality must be carefully used because of their increased radiosensitivity, higher effective radiation doses, and longer life expectancy.

Usefulness of Multidetector Computed Tomography for the Initial Assessment of Blunt Abdominal Trauma Patients

BACKGROUND

The prompt detection and accurate localization of abdominal injuries are difficult. Some diagnostic modalities, including laboratory tests, ultrasound, and diagnostic peritoneal lavage (DPL) were used to evaluate patients with blunt abdominal trauma, with various advantages and pitfalls. We aimed to evaluate the risk and benefit of using multidetector computed tomography (MDCT) as an initial assessment tool for proper diagnosis and treatment planning of patients with blunt abdominal trauma.

METHODS

Two hundred fifty-two patients with blunt abdominal trauma were prospectively enrolled. Multidetector computed tomography was performed during resuscitation. The risk and benefit of using MDCT in the diagnosis and planning of treatment were analyzed.

RESULTS

The time required for a MDCT examination averaged 10.2 minutes. Of the studies done, 224 revealed abdominal injuries. Of those, 34 were performed in patients with unstable hemodynamic status without adverse effect. Prompt diagnosis and proper treatment were given according to the MDCT findings. A total of 43 (17.1%) MDCTs showed contrast extravasation. Active bleeding was confirmed in all and treated with transarterial embolization (30) or surgery (13). Another 58 patients sustained bowel, mesenteric, or pancreatic injuries (BMPI) necessitating laparotomy. The sensitivity, specificity, and accuracy of MDCT in identifying patients with active bleeding or BMPI were all 100%.

CONCLUSIONS

Multidetector computed tomography was useful as a second line initial assessment tool to identify injuries and determine treatment planning in blunt abdominal trauma patients. No increased risk was found if the facility is readily available, the protocol is well designed, and the patient is well prepared.

Appendicitis in Children: Low-Dose CT with a Phantom-based Simulation Technique—Initial Observations

PURPOSE

To retrospectively determine the accuracy of low-dose (20-mAs) computed tomography (CT) in the diagnosis of acute appendicitis in children by using a technique that enables the simulation of human CT scans acquired at a lower tube current given the image acquired at a standard dose.

MATERIALS AND METHODS

Institutional review board approval was obtained, informed consent was not required, and the study was HIPAA compliant. The authors reviewed 100 standard-dose pediatric abdominal-pelvic CT scans (50 positive and 50 negative scans) obtained in 100 patients and corresponding simulated low-dose (20-mAs) scans. The standard-dose scans were obtained for evaluation in patients suspected of having appendicitis. Scans were reviewed in randomized order by four experienced pediatric radiologists. The patients with positive findings included 21 girls (mean age, 9.2 years) and 29 boys (mean age, 8.4 years). The patients with negative findings included 28 girls (mean age, 9.2 years) and 22 boys (mean age, 8.4 years). Simulation was achieved by adding noise patterns from repeated 20-mAs scans of a pediatric pelvis phantom to the original scans obtained with a standard tube current. Observers recorded their confidence in the diagnosis of appendicitis by using a six-point scale. Dose-related changes were analyzed with generalized estimating equations and the nonparametric sign test.

RESULTS

There was a statistically significant (P < .001, sign test) decrease in both sensitivity and accuracy with a lower tube current, from 91.5% with the original tube current to 77% with the lower tube current. A low dose was the only statistically significant (P < .001) risk factor for a false-negative result. The specificity was unchanged at 94% for both the images obtained with the original tube current and the simulated low-dose images. The overall accuracy decreased from 92% with the original dose to 86% with the low dose.

CONCLUSION

Preliminary findings indicate that it is feasible to optimize the CT dose used to evaluate appendicitis in children by using phantom-based computer simulations.

Advances in paediatric tumour imaging

There have been a number of major advances in imaging technology in recent years. Here we discuss in detail multislice CT and PET, since these are the two modalities generating the most interest in cancer imaging, but which also have the potential for significantly increasing the radiation burden in the paediatric population. In addition, we focus on the implications of the new Response Evaluation Criteria In Solid Tumours (RECIST) guidelines, which describe a significant new method of tumour size measurement.

Sedation for pediatric CT scanning: is radiology becoming a drug-free zone?

INTRODUCTION

Cooperation for a diagnostic study is a frequent indication for pediatric procedural sedation. This study examines the continued need for sedation in the era of fast helical computerized tomography (CT) scanners.

METHODS

Medical records of children younger than 72 months undergoing CT scans were systematically reviewed to identify the use of procedural sedation to complete their diagnostic studies. Statistical analysis was through ANOVA and regression modeling.

RESULTS

A total of 104 patients underwent 122 CT studies. Requests originated from 3 sources: 59.8% ED (n = 73), 38.5% Neonatal Intensive Care Unit (n = 47), and 1.6% Pediatric Ward (n = 2). Studies performed included: 79.5% head/facial (n = 97), 15.6% abdomen/pelvis (n = 19), and 5.9% other (n = 6). The mean ages of all study patients was 23.4 (+/-2.4) months with a median of 14 months. Only 8.6% patients (n = 9) received any sedation. The mean age of sedated patients was 18.8 (+/-2.7) months with a median of 21 months. With the exception of one 4-month-old, all other sedated children were between 12 and 30 months. Sedative use occurred in 36.4% of patients in this age group, which was significantly greater than the remainder of the study group (OR 56.5, 95% CI 9-1091, P < 0.001) Sedative agents used included: diphenhydramine (4), pentobarbital (1), propofol (1), ketamine (1), midazolam (1), diphenhydramine/pentobarbital (1).

CONCLUSIONS

Procedural sedation is infrequently used in infants and young children undergoing helical CT studies.

Technique of Pediatric Thoracic CT Angiography

CT angiography is now an accepted application of contemporary multidetector row CT. Faster scanning, thinner slices, and improvement in intravenous contrast enhancement are benefits that have offered unique opportunities for pediatric thoracic angiographic evaluation, and often obviate routine angiography. Pediatric CT angiography can be challenging but adherence to a relatively straightforward step-by-step method, emphasizing patient preparation and technical familiarity, can result in excellent examinations even in the smallest infants and most complex clinical scenarios.

Imaging Evaluation of Chest Wall Disorders in Children

This article discusses the imaging evaluation of chest wall disorders in children.

Pediatric abdominal applications of multidetector-row CT

The introduction of multidetector technology of computed tomography (CT) into clinical practice has increased using CT as modality of choice for most body parts. In spite of some disadvantages of CT such as radiation exposure and using iodinated contrast medium, some facilities gathered by multidetector computed tomography (MDCT) such as faster scanning time and high-resolution imaging technique have improved pediatric CT applications. Less using intravenous and oral contrast medium, less sedation rate, decreased radiation exposure are very practical advantages of MDCT in abdominal imaging of pediatric population. In this review, technical details of these advantages of MDCT for pediatric population and some examples of improved imaging and diagnostic capabilities arising from MDCT for pediatric abdominal applications will be presented.

Pediatric thoracic CT angiography

One of the principal benefits of contemporary multidetector row computed tomography (MDCT) has been the ability to obtain high-quality data sets for evaluation of the cardiovascular system. The benefits of the greater number of detector rows and submillimeter image thicknesses were quickly recognized and are especially advantageous in children. For example, since imaging is performed so quickly, issues with motion are minimized. This is a substantial benefit of CTA compared with MR imaging, the traditional noninvasive cross sectional modality for pediatric cardiovascular imaging. This, together with faster and more powerful computers, including improved transfer and storage capabilities, offers improved depiction of the heart, great vessels, other vasculature, and adjacent intrathoracic structures in a fashion that is well accepted by clinical colleagues. In order to be successful, however, one must have an understanding of the technology and often unique technical considerations in infants and children. With this familiarity, excellent cardiovascular examinations can be performed even in the most challenging case.

Strategies for formulating appropriate MDCT techniques when imaging the chest, abdomen, and pelvis in pediatric patients

OBJECTIVE

Our aim was to formulate appropriate MDCT chest and abdominopelvic CT scan protocols for pediatric patients.

MATERIALS AND METHODS

Surface radiation dose measurements from a set of anthropomorphic phantoms (nominal 1 year old, 5 year old, and 10 year old) and an adult phantom were compared with standard CT dose index measurements. Image-noise values on axial 5-mm-thick anthropomorphic phantom images were obtained as a measure of image quality.

RESULTS

Peripheral CT dose index values obtained with the standard 16-cm acrylic phantom were within approximately 10% of the CT surface dose measurements for the pediatric anthropomorphic phantoms for both chest and abdominopelvic scan protocols. The noise value for the adult phantom image acquired using a typical clinical CT technique was identified, and targeting this level of noise for pediatric CT examinations resulted in a decrease in dose of 60-90%. Initially, 80 kVp was selected for use with very small children; however, beam-hardening artifacts were severe enough to cause us to abandon this option. Current pediatric protocols at M. D. Anderson Cancer Center rely on 100- and 120-kVp settings. The display field-of-view parameter can be used as a surrogate for patient size to develop clinical pediatric CT protocol charts.

CONCLUSION

CT dose index measurements obtained using the 16-cm standard acrylic phantom are sufficiently accurate for estimating chest and abdominopelvic CT entrance exposures for pediatric patients of the same approximate size as the anthropomorphic phantoms used in this study. Image-noise measurements can be used to adjust chest and abdominopelvic CT techniques for pediatric populations, resulting in a decrease in measured entrance dose by 60-90%.

MDCT Evaluation of Thoracic Aortic Anomalies in Pediatric Patients and Young Adults:Comparison of Axial, Multiplanar, and 3D Images

OBJECTIVE

The objective of our study was to compare accuracies of axial, multiplanar, and 3D volume-rendered images in the diagnosis of thoracic aortic anomalies in pediatric patients and young adults.

MATERIALS AND METHODS

Fourteen patients, 17 days to 20 years old, with thoracic aortic anomalies underwent MDCT using axial, multiplanar, and 3D volume-rendering imaging. All images were reviewed by three radiologists for position of the aortic arch, coarctation, vascular compression of the airway, collateral vessel formation, and aortopulmonary shunts (patent ductus arteriosus). Final diagnosis was determined by echocardiography, conventional angiography, bronchoscopy, or surgery. Diagnostic accuracy, sensitivity, and interobserver agreement were evaluated.

RESULTS

Average accuracies (average of the three observers for a correct diagnosis) were greater than or equal to 96% for diagnoses of aortic position and airway narrowing on all image types. For the diagnosis of coarctation, average sensitivities (average of the three observers for a true diagnosis) were 73% for axial, 100% for multiplanar, and 100% for 3D volume-rendered images. For the diagnosis of patent ductus arteriosus, average sensitivities were 78% for axial, 94% for multiplanar, and 89% for 3D volume-rendered images. No patients in this study had collateral vessel formation. For the diagnosis of absence of collateral vessel formation, average sensitivities were 100% for axial, 100% for multiplanar, and 100% for 3D volume-rendered images. There were no significant statistical differences in diagnostic performances, agreement with truth, or confidence scores among observers or imaging formats (p > 0.05).

CONCLUSION

Axial, multiplanar, and 3D volume-rendered images serve equally well as methods for assessing the side of the aorta to diagnose anomalies. For evaluation of coarctation and patent ductus arteriosus, multiplanar and 3D volume-rendered images perform slightly better than axial images.

Impact of multislice CT on imaging of acute abdominal disease

The increased speed, greater coverage, and thinner slices of MSCT are exciting developments in radiology, and these feature should only improve with newer generation multislice scanners. The impact of this technology on abdominal imaging has just begun.

[Low dose multislice CT in the pediatric patient]

In the past years, multislice CT (MS-CT) has become an important diagnostic modality for the radiological evaluation of the thorax in children and adolescents. However, the higher stochastic radiation risks in pediatric patients, as compared to adults, necessitate a prudent use of MS-CT. This article presents an overview of the benefits of multislice CT and a variety of possibilities for radiation reduction in pediatric patients of different ages.