Faculty Bibliography

BACKGROUND: Rapid and accurate diagnosis of appendicitis, particularly with respect to the presence or absence of perforation, is essential in guiding appropriate management. Although many studies have explored sonographic findings associated with acute appendicitis, few investigations discuss specific signs that can reliably differentiate perforated appendicitis from acute appendicitis prior to abscess formation. OBJECTIVE: The purpose of our study was to identify sonographic findings that improve the specificity of US in the diagnosis of perforated appendicitis. Our assessment of hepatic periportal echogenicity, detailed analysis of intraperitoneal fluid, and formulation of select constellations of sonographic findings expands upon the literature addressing this important diagnostic challenge. MATERIALS AND METHODS: We retrospectively reviewed 116 abdominal US examinations for evaluation of abdominal pain in children ages 2 to 18 years from January 2008 to September 2011 at a university hospital pediatric radiology department. The study group consisted of surgical and pathology proven acute appendicitis (n = 51) and perforated appendicitis (n = 22) US exams. US exams without a sonographic diagnosis of appendicitis (n = 43) confirmed by follow-up verbal communication were included in the study population as the control group. After de-identification, the US exams were independently reviewed on a PACS workstation by four pediatric radiologists blinded to diagnosis and all clinical information. We recorded the presence of normal or abnormal appendix, appendicolith, appendiceal wall vascularity, thick-walled bowel, dilated bowel, right lower quadrant (RLQ) echogenic fat, increased hepatic periportal echogenicity, bladder debris and abscess or loculated fluid. We also recorded the characteristics of intraperitoneal fluid, indicating the relative quantity (number of abdominal regions) and quality of the fluid (simple fluid or complex fluid). We used logistic regression for correlated data to evaluate the association of diagnosis with the presence versus absence of each US finding. We conducted multivariable analysis to identify constellations of sonographic findings that were predictive of perforated appendicitis. RESULTS: The individual US findings of abscess/loculated fluid, appendicolith, dilated bowel and increased hepatic periportal echogenicity were significantly associated with perforated appendicitis when compared with acute appendicitis (P < 0.01). The sonographic observation of increased hepatic periportal echogenicity demonstrated a statistically significant association with perforated appendicitis compared with acute appendicitis (P < 0.01). The presence of complex fluid yielded a specificity of 87.7% for perforated appendicitis compared with the acute appendicitis group. The US findings of >/=2 regions or >/=3 regions with fluid had specificity of 87.3% and 99.0%, respectively, for perforated appendicitis compared with the acute appendicitis group. Select combinations of sonographic findings yielded high specificity in the diagnosis of perforated appendicitis compared with acute appendicitis. These constellations yielded higher specificity than that of each individual finding in isolation. The constellation of dilated bowel, RLQ echogenic fat, and complex fluid had the highest specificity (99.5%) for perforated appendicitis (P < 0.01). CONCLUSION: Our study demonstrates that identification of select constellations of findings using abdominal sonography, in addition to focused US examination of the right lower quadrant, can improve sonographic diagnosis of perforated appendicitis in the pediatric population.

BACKGROUND: Shielding of the gonads is a dose-saving strategy in pediatric radiography and its use is the law in New York and the majority of other states. However, routine use of gonadal shields is controversial because of concerns that important diagnostic information can be obscured. OBJECTIVE: The purpose of this study was to assess the frequency and spatial distribution of key findings on portable neonatal abdominal radiographs. MATERIALS AND METHODS: We reviewed the 2,544 portable neonatal intensive care unit anteroposterior abdominal radiographs performed in 2010 at a university medical center, of which 962 were inadequately shielded. These 962 radiographs were reviewed by pairs of pediatric radiologists for the presence of findings in different regions, including bowel abnormalities, pneumatosis, free air, inguinal hernias, osseous abnormalities, and catheter/tube tips. RESULTS: The fewest pertinent findings were present below the level of the sacrosciatic notches (n = 181, 18.8%). Of the 853 abnormalities below the level of the iliac crests in our cohort, six were isolated to these regions, whereas others had concomitant abnormalities more superiorly. Of 35 radiographs with pneumatosis or suspected pneumatosis in the pelvis, 33 had pneumatosis in more superior regions. Suspected free air was never isolated to the pelvis. Osseous abnormalities were only present in the pelvis below the sacrosciatic notch, and 37.5% of lower extremity catheters terminated below the level of the sacrosciatic notches. CONCLUSION: Pertinent findings on neonatal intensive care unit abdominal radiographs are rarely isolated to the pelvic regions.

Purpose or Case Report: With the advent of iterative reconstruction, the opportunity for decreasing radiation dose has become increasingly viable. The purpose of our study is to develop a method for optimizing existing adolescent pediatric body CT protocols with the goal of achieving lower dose without compromising image quality using raw data based iterative reconstruction. Methods & Materials: A customized anthropomorphic abdominal CT phantom composed of "tissue-equivalent" material containing inserts simulating an enhancing renal lesion and non-enhancing renal cyst was scanned on three 128 slice CT scanners (Siemens Definition Edge, AS and FLASH). Scanning parameters included 120 kV and effective mAs from 20 to 140 by increments of 20. Each data set was reconstructed at a slice thickness of 4 mm with soft tissue algorithm (B40) and corresponding iterative reconstruction (SAFIRE, I40) with strengths 1 through 3. Attenuation and noise measurements were acquired at two contiguous slices for the non-enhancing cyst and enhancing lesion, at the same z-axis for all image sets. CTDIvol was recorded for each scan. Mean attenuation and noise values were compared between scanners and within each algorithm using ANOVA and t-test. Results: No differences in mean attenuation of the enhancing lesion were observed between reconstruction algorithms (B40: 38.8+4.7, I40[1]: 38.6+4.6, I40[2]: 38.6+4.5, I40[3]: 38.4+4.5 HU) and scanner types (Edge: 38.1+2.9, AS: 37+6, FLASH: 40.6+3.3 HU). Mean noise for the enhancing lesion and cyst were not statistically different between the scanners. Noise was signficantly lower for both renal inserts with iterative reconstruction (p<0.001) for strength 1 (10%), strength 2 (20%) and strength 3 (30%) compared to B40. Average CTDIvol for the CT scanners (Siemens Definition Edge, AS, FLASH) were 4.3+2.0, 4.3+2.0 and 4.5+2.1, respectively. Graphical representation of the data for each algorithm enabled identification of corresponding noise levels at decreasing effective mAs. For !

Purpose or Case Report: Distinguishing perforated from non-perforated appendicitis in children, a known limitation of ultrasound, may alter surgical management. We evaluated the diagnostic utility of select groups of sonographic findings for diagnosis of perforated appendicitis. Methods & Materials: With IRB approval, we retrospectively reviewed 116 abdominal ultrasound (US) exams obtained for evaluation of abdominal pain in children aged 2-18 years from 1/2008 to 9/2011 at a university hospital pediatric radiology department. The study group consisted of surgical and pathology proven acute appendicitis (n=51) and perforated appendicitis (n=22) US exams. Negative US exams for appendicitis (n=43) confirmed by follow up verbal communication comprised the control group. The de-identified US exams were independently reviewed on PACS workstations by four experienced pediatric radiologists blinded to diagnosis and clinical information. The radiologists recorded the presence of dilated bowel, right lower quadrant (RLQ) echogenic fat, increased hepatic periportal echogenicity, and intraperitoneal fluid, indicating quantity (number of abdominal quadrants) and quality of the fluid (simple or complex). Logistic regression for correlated data was used to evaluate the association of diagnosis with the presence versus absence of each US finding in addition to selected groups of US findings. Results: The select groups of findings included increased hepatic periportal echogenicity, echogenic fat, and complex fluid yielding a specificity of 95.0%for perforated appendicitis; increased hepatic periportal echogenicity and 2+ quadrants of fluid yielding a specificity of 96.1%; increased hepatic periportal echogenicity and dilated bowel with a specificity of 98.0%; and dilated bowel, echogenic fat and complex fluid with a specificity of 99.5%. The above constellations of sonographic findings yielded higher specificities than that of each of the following individual findings in isolation: presence of complex fluid (9!

PURPOSE: To assess the efficacy and accuracy of ultrasonography (US) and selective computed tomography (CT) in the diagnosis of acute appendicitis in children. METHODS: A retrospective review of all ultrasound evaluations for appendicitis from July 1, 2003, to June 30, 2010, was conducted at two urban pediatric centers. Beginning in 2003, a multi-disciplinary diagnostic protocol was implemented to reduce radiation exposure employing US as the initial imaging modality followed by CT for non-diagnostic US studies in patients with an equivocal clinical presentation. The imaging, operative findings, and pathology of 802 patients (365 females, 437 males, age less than 18years) with suspected appendicitis were reviewed. The sensitivity, specificity, predictive value, and negative appendectomy rate of the protocol were analyzed. A telephone survey was conducted of patients discharged without a diagnosis of appendicitis to evaluate the missed appendicitis rate. RESULTS: Of the 601 pediatric appendectomies performed, a total of 275 (46%) were diagnosed by protocol. The selective protocol had a sensitivity of 94.2%, specificity of 97.5%, positive predictive value of 95.2%, and negative predictive value of 97.0%. The negative appendectomy rate was 1.82%, and the missed appendicitis rate was 0%. No patient discharged after only ultrasound evaluation without undergoing surgery reported missed appendicitis on the survey (41.7% response rate). Protocol use increased from 6.7% to 88.3%. US was the sole imaging modality in 630 of all 802 patients (78.6%). CONCLUSIONS: US followed by selective CT for the diagnosis of acute appendicitis is useful and accurate. This has important implications in the reduction of childhood radiation exposure.

BACKGROUND: In accordance with ALARA, minimizing radiation exposure associated with voiding cystourethrograms (VCUG) is of critical importance. Advances in fluoroscopic technology might help achieve this goal. OBJECTIVE: To determine the efficacy of fluoroscopic image capture compared to conventional digital radiographic spot (DRS) images in voiding cystourethrograms (VCUG) for the evaluation of vesicoureteral reflux (VUR) in children. MATERIALS AND METHODS: The study was a retrospective review of 65 VCUG examinations (130 kidney/ureter units). Each examination consisted of fluoroscopically captured spot (FCS) images and the corresponding DRS images. Each set of images was evaluated by three pediatric radiologists for the diagnosis of VUR for a total of 390 kidney/ureter units reviewed. Using the DRS image set as the reference standard, the efficacy of the FCS images for diagnosing reflux was determined. RESULTS: The diagnostic accuracy of the FCS images in terms of the binary characterization of reflux as negative or positive was 97.2% (379/390). The sensitivity of the FCS images was 92.6% (88/95); the specificity of the FCS images was 98.6% (291/295). CONCLUSION: Fluoroscopically captured images are adequate in documenting absence of VUR on VCUG examinations, obviating the need for radiographic spot images and resulting in reduction in radiation exposure

Concomitant hereditary spherocytosis and sickle cell trait, although extremely rare, could potentially lead to splenic sequestration or infarction. We report here the first case of splenic infarction in a child with hereditary spherocytosis and sickle cell trait while flying on a commercial aircraft. The presence of hypoxia, hemoconcentrated erythrocytes, and sickle hemoglobin created the perfect environment for clinical sequelae