Carrie Ruzal-Shapiro

Ultrasonography/mri versus ct for diagnosing appendicitis

BACKGROUND: Cross-sectional imaging increases accuracy in diagnosing appendicitis. We hypothesized that a radiation-free imaging pathway of ultrasonography selectively followed by MRI would not change clinical end points compared with computed tomography (CT) for diagnosis of acute appendicitis in children. METHODS: We retrospectively reviewed children (<18 years old) who had diagnostic imaging for suspected acute appendicitis between November 2008 and October 2012. Before November 2010 CT was used as the primary imaging modality (group A); subsequently, ultrasonography was the primary imaging modality followed by MRI for equivocal findings (group B). Data collected included time from triage to imaging and treatment and results of imaging and pathology. RESULTS: Six hundred sixty-two patients had imaging for suspected appendicitis (group A = 265; group B = 397, of which 136 [51%] and 161 [41%], respectively, had positive imaging for appendicitis). Negative appendectomy rate was 2.5% for group A and 1.4% for group B. Perforation rate was similar for both groups. Time from triage to antibiotic administration and operation did not differ between groups A and B. There was higher proportion of positive imaging and appendectomies in group A and thus more negative imaging tests in group B (ultrasonography and MRI), but diagnostic accuracy of the 2 imaging pathways was similar. CONCLUSIONS: In children with suspected acute appendicitis, a radiation-free diagnostic imaging of ultrasonography selectively followed by MRI is feasible and comparable to CT, with no difference in time to antibiotic administration, time to appendectomy, negative appendectomy rate, perforation rate, or length of stay.

Value of Gadolinium-Enhanced MRI in Detection of Acute Appendicitis in Children and Adolescents

OBJECTIVE The aim of this study was to determine both the value of gadolinium-enhanced MRI in children with suspected acute appendicitis and the best sequences for detecting acute appendicitis, to thereby decrease imaging time. MATERIALS AND METHODS This was a retrospective review of pediatric patients with suspected appendicitis who had undergone MRI at our institution between 2010 and 2011 after an indeterminate ultrasound examination. MRI examinations included T1-weighted unenhanced and contrast-enhanced, T2-weighted, and balanced steady-state free precession (SSFP) sequences in axial and coronal planes. Sequences were reviewed together and individually by five radiologists who were blinded to the final diagnosis. Radiologists were asked to score their confidence of appendicitis diagnosis using a 5-point scale. The diagnostic performance of each MR sequence was obtained by comparing the mean area under the curve (AUC) using receiver operating characteristic (ROC) analysis. RESULTS A total of 49 patients with clinically suspected appendicitis were included, of whom 16 received a diagnosis of appendicitis. The mean AUCs for reviewing all sequences together, contrast-enhanced sequences alone, T2-weighted sequences alone, and balanced SSFP alone were 0.984, 0.979, 0.944, and 0.910, respectively. No significant difference was observed between reviewing all sequences together versus contrast-enhanced sequences alone (p = 0.90) and T2-weighted sequences alone (p = 0.23). A significant difference was observed between contrast-enhanced sequences and balanced SSFP (p < 0.03). CONCLUSION Gadolinium-enhanced images and T2-weighted images are most helpful in the assessment of acute appendicitis in the pediatric population. These findings have led to protocol modifications that have reduced imaging time.

Tuberculous Arthritis in Children: Diagnosis by Needle Biopsy of the Synovium

In two children ages 8 months and 4 years, tuberculous synovitis of the knee was suggested by pathologic examination of synovial tissue obtained through needle biopsy. Culture of the biopsy material was positive for Mycobacterium tuberculosis in one case. In this child, the tuberculin test was negative, in the absence of anergy, at the time the child was first evaluated, and the primary lung lesion was not identified by the radiologist.Tuberculous synovitis has not previously been recognized as part of primary tuberculosis during the early weeks when the tuberculin skin test may be negative. Magnetic resonance imaging (MRI) is a sensitive modality for demonstrating joint fluid, synovial hypertrophy, and associated osteomyelitis, if present. With the increasing frequency of cases of tuberculosis in the population, greater awareness of the risk of tuberculous arthritis in childhood is important in order to recognize this unusual presentation. If negative early on, the tuberculin skin test should be repeated after 6 weeks of arthritis. A needle biopsy of the synovium is helpful and appropriate in all children with monoarticular arthritis who have a positive tuberculin skin test.

Prevalence of abnormal cases in an image bank affects the learning of radiograph interpretation

Medical Education 2012: 46: 289–298

New automated fluoroscopic systems for pediatric applications

Pediatric patients are at higher risk to the adverse effects from exposure to ionizing radiation than adults. The smaller sizes of the anatomy and the reduced X‐ray attenuation of the tissues provide special challenges. The goal of this effort is to investigate strategies for pediatric fluoroscopy in order to minimize the radiation exposure to these individuals, while maintaining effective diagnostic image quality. Modern fluoroscopy systems are often entirely automated and computer controlled. In this paper, various selectable and automated modes are examined to determine the influence of the fluoroscopy parameters upon the patient radiation exposures and image quality. These parameters include variable X‐ray beam filters, automatic brightness control programs, starting kilovolt peak levels, fluoroscopic pulse rates, and other factors. Typical values of radiation exposure rates have been measured for a range of phantom thicknesses from 5 cm to 20 cm of acrylic. Other factors that have been assessed include spatial resolution, low‐contrast discrimination, and temporal resolution. The selection menu for various procedures is based upon the examination type, anatomical region, and patient size. For pediatric patients, the automated system can employ additional filtration, special automatic brightness control curves, pulsed fluoroscopy, and other features to reduce the patient radiation exposures without significantly compromising the image quality. The benefits gained from an optimal selection of automated programs and settings for fluoroscopy include ease of operation, better image quality, and lower patient radiation exposures. PACS numbers: 87.59.‐e, 87.62.+n

The diagnosis of abdominal neuroblastoma: relative roles of ultrasonography, CT, and MRI.

Abdominal neuroblastoma is reviewed in terms of its diagnosis, including in utero, at birth, and through infancy into childhood. Age at diagnosis remains the best predictor of survival, with infants under 1 year of age having almost 100% cure. Ultrasonography and magnetic resonance imaging (MRI) are the recommended diagnostic modalities to stage the abdominal primary, although computed tomography (CT) (including myelography) is still widely and efficiently used. Examples are given of each stage.

Test characteristics of the 3-view abdominal radiograph series in the diagnosis of intussusception.

Objectives: To determine the test characteristics of the 3-view abdominal radiograph series to exclude intussusception in children presenting to the pediatric emergency department. Methods: We performed a single-center retrospective review of children for whom supine, prone, and lateral decubitus abdominal radiographs were performed as part of our standard diagnostic evaluation for intussusception. A pediatric radiologist masked to the patients clinical data and outcome reviewed all radiographs. The criterion evaluated was whether air was visualized in the ascending colon on each of the 3 radiograph views. We determined the presence or absence of intussusception hierarchically by definitive radiological study report, surgical operative note, or clinical outcome. Results: We analyzed 179 patients, of whom 27 (15.1%) were diagnosed with intussusception. The test characteristics of the 3-view radiograph series in the diagnosis of intussusception when all 3 views had air in the ascending colon were sensitivity of 100% (95% confidence interval [CI] 87-100), specificity of 18.4% (95% CI, 12.3-24.6), likelihood ratio for a negative test of 0 (95% CI, 0.01-1.53), and negative predictive value (NPV) of 100% (lower bound 95% CI, 98%). When at least 2 views had air in the ascending colon, the test characteristics were sensitivity of 96.3% (95% CI, 89.2-100), specificity of 41.4% (95% CI, 33.6-49.3), likelihood ratio for a negative test of 0.09 (0.01-0.62), and NPV of 98.4 (95% CI, 95.2-100). Conclusions: Using specific criteria, the presence of air in the ascending colon on 2 or 3 abdominal radiograph views has the potential to substantially decrease the likelihood of or exclude intussusception.

Non-union of pediatric fibula fractures: Easy to overlook, painful to ignore

Fracture non-union in the pediatric population may span the age range from childhood to adolescence. Fracture non-union in children and adolescents is often due to an underlying cause such as affliction with neurofibromatosis or osteogenesis imperfecta. Although less commonly seen, non-union may occur in the otherwise healthy pediatric population. We report three cases of fracture non-union of the distal end of the fibula in the pediatric age group. All three were characterized by persistent local pain and tenderness following injury with radiographic evidence of fracture non-union. All three had undergone conservative treatment with extended periods of immobilization. Following surgery, all three had marked improvement of their local symptomatology. One patients course was complicated by reflex sympathetic dystrophy syndrome. In two patients, resection of the un-united fragment at the distal fibula resulted in marked relief from pain without any increase in ankle instability. We postulate that the fracture non-union resulted in a fibrotic reaction that was so extensive that ankle stability was maintained even after removal of the fracture fragment.

Estimating Effective Dose of Radiation From Pediatric Cardiac CT Angiography Using a 64-MDCT Scanner: New Conversion Factors Relating Dose-Length Product to Effective Dose

OBJECTIVE The purpose of this study is to determine the conversion factors that enable accurate estimation of the effective dose (ED) used for cardiac 64-MDCT angiography performed for children. MATERIALS AND METHODS Anthropomorphic phantoms representative of 1- and 10-year-old children, with 50 metal oxide semiconductor field-effect transistor dosimeters placed in organs, underwent scanning performed using a 64-MDCT scanner with different routine clinical cardiac scan modes and x-ray tube potentials. Organ doses were used to calculate the ED on the basis of weighting factors published in 1991 in International Commission on Radiological Protection (ICRP) publication 60 and in 2007 in ICRP publication 103. The EDs and the scanner-reported dose-length products were used to determine conversion factors for each scan mode. The effect of infant heart rate on the ED and the conversion factors was also assessed. RESULTS The mean conversion factors calculated using the current definition of ED that appeared in ICRP publication 103 were as follows: 0.099 mSv · mGy-1 · cm-1, for the 1-year-old phantom, and 0.049 mSv · mGy-1 · cm-1, for the 10-year-old phantom. These conversion factors were a mean of 37% higher than the corresponding conversion factors calculated using the older definition of ED that appeared in ICRP publication 60. Varying the heart rate did not influence the ED or the conversion factors. CONCLUSION Conversion factors determined using the definition of ED in ICRP publication 103 and cardiac, rather than chest, scan coverage suggest that the radiation doses that children receive from cardiac CT performed using a contemporary 64-MDCT scanner are higher than the radiation doses previously reported when older chest conversion factors were used. Additional up-to-date pediatric cardiac CT conversion factors are required for use with other contemporary CT scanners and patients of different age ranges.

Accuracy of plain radiographs to exclude the diagnosis of intussusception.

Objectives To prospectively determine the test characteristics of the 3-view abdominal radiograph to decrease the likelihood of ileocolic intussusception. Methods We conducted a prospective cross-sectional study of children aged 3 months to 3 years suspected of having intussusception at a children’s hospital emergency department. Clinicians obtained supine, prone, and left lateral decubitus radiographs. We determined the presence or absence of intussusception by air enema, ultrasound, operative report, or clinical follow-up. A masked pediatric radiologist reviewed all radiographs. The criteria evaluated were whether air was visualized in the ascending colon on each view and in the transverse colon on the supine view. Results Nineteen (14.8%) of 128 patients had intussusception. Using air in the ascending colon on all 3 views as the diagnostic criteria, the test characteristics of the 3-view radiograph were sensitivity, 100% (95% confidence interval [CI], 79.1–100); specificity, 17.4% (95% CI, 11.1–26.1); negative predictive value, 100% (95% CI, 79.1–100); and likelihood ratio of a negative test, 0. When 2 or more of 3 views had air in the ascending colon, sensitivity decreased to 89.5% (95% CI, 75.7–100) and specificity improved to 45.0% (95% CI, 35.6–54.3). Air in the transverse colon had moderate sensitivity, 84.2% (95% CI, 67.8–100), but further improved specificity, 63.3% (95% CI, 54.2–72.4). Conclusions The presence of air in the ascending colon on the 3-view abdominal radiograph can decrease the likelihood of or exclude intussusception. When clinical suspicion is low, the presence of specific criterion on a 3-view abdominal radiograph series may obviate the need for further studies.