Inter-radiologist agreement for CT scoring of pediatric splenic injuries and effect on an established clinical practice guideline.

BACKGROUND: The American Pediatric Surgical Association (APSA) advocates for the use of a clinical practice guideline to direct management of hemodynamically stable pediatric spleen injuries. The clinical practice guideline is based on the CT score of the spleen injury according to the American Association for the Surgery of Trauma (AAST) CT scoring system. OBJECTIVE: To determine the potential effect of radiologist agreement for CT scoring of pediatric spleen injuries on an established APSA clinical practice guideline. MATERIALS AND METHODS: We retrospectively analyzed blunt splenic injuries occurring in children from January 2007 to January 2012 at a single level 1 trauma center (n = 90). Abdominal CT exams performed at clinical presentation were reviewed by four radiologists who documented the following: (1) splenic injury grade (AAST system), (2) arterial extravasation and (3) pseudoaneurysm. Inter-rater agreement for AAST injury grade was assessed using the multi-rater Fleiss kappa and Kendall coefficient of concordance. Inter-rater agreement was assessed using weighted (AAST injury grade) or prevalence-adjusted bias-adjusted (binary measures) kappa statistics; 95% confidence intervals were calculated. We evaluated the hypothetical effect of radiologist disagreement on an established APSA clinical practice guideline. RESULTS: Inter-rater agreement was good for absolute AAST injury grade (kappa: 0.64 [0.59­0.69]) and excellent for relative AAST injury grade (Kendall w: 0.90). All radiologists agreed on the AAST grade in 52% of cases. Based on an established clinical practice guideline, radiologist disagreement could have changed the decision for intensive care management in 11% (10/90) of children, changed the length of hospital stay in 44% (40/90), and changed the time to return to normal activity in 44% (40/90). CONCLUSION: Radiologist agreement when assigning splenic AAST injury grades is less than perfect, and disagreements have the potential to change management in a substantial number of pediatric patients.

Spine ultrasound imaging in the newborn.

Ultrasound of the spine in the neonate is widely used as the initial modality to evaluate spinal canal anatomy, anatomical variants, and congenital malformations. The spinal canal and its contents are best visualized in the newborn and young infant owing to incomplete ossification of the posterior vertebral elements.

Magnetic resonance imaging of pediatric pelvic masses.

Both benign and malignant pelvic masses are encountered in the pediatric population. Although ultrasonography remains the modality of choice for initial evaluation of a pediatric pelvic mass, in selected cases magnetic resonance (MR) imaging can add important diagnostic information. MR imaging has several advantages over ultrasonography and computed tomography, including superior contrast resolution and an ability to characterize abnormalities based on unique tissue characteristics. MR evaluation assists in lesion characterization, presurgical planning, and staging when a malignancy is suspected. MR imaging also offers a nonionizing imaging modality for long-term follow-up of patients undergoing therapy for malignant pelvic masses.

Another dimension to survival: predicting outcomes with fetal MRI versus prenatal ultrasound in patients with congenital diaphragmatic hernia.

PURPOSE: A major determinant of survival in patients with congenital diaphragmatic hernia (CDH) is severity of pulmonary hypoplasia. This study addresses the comparative effectiveness of prenatal methods of lung assessment in predicting mortality, extracorporeal membrane oxygenation (ECMO), and ventilator dependency. METHODS: We retrospectively reviewed all patients born with isolated CDH between 2004 and 2008. Lung-to-head ratio (LHR) and observed-to-expected LHR (OELHR) were obtained from prenatal ultrasounds. Percent-predicted lung volume (PPLV) was obtained from fetal MRI (fMRI). Postnatal data included in-hospital mortality, need for ECMO, and ventilator dependency at day-of-life 30. RESULTS: Thirty-seven patients underwent 81 prenatal ultrasounds, while 26 of this sub-cohort underwent fMRI. Gestational age during imaging study was associated with LHR (p=0.02), but not OELHR (p=0.12) or PPLV (p=0.72). PPLV, min-LHR, and min-OELHR were each associated with mortality (p=0.03, p=0.02, p=0.01), ECMO (p<0.01, p<0.01, p=0.03), and ventilator dependency (p<0.01, p<0.01, p=0.02). For each outcome, PPLV was a more discriminative measure, based on Akaike's information criterion. Using longitudinal analysis techniques for patients with multiple ultrasounds, OELHR remained associated with mortality (p=0.04), ECMO (p=0.03), and ventilator dependency (p=0.02), while LHR was associated with ECMO (p=0.01) and ventilator dependency (p=0.02) but not mortality (p=0.06). CONCLUSION: When assessing fetuses with CDH, OELHR and PPLV may be most helpful for counseling regarding postnatal outcomes.

Developmental impact and lesion maturation of histotripsy-mediated non-invasive tissue ablation in a fetal sheep model.

Non-invasive histotripsy therapy has previously been used to achieve precise fetal tissue ablation in a sheep model. To further assess the clinical viability of the technique, this study investigated potential effects of histotripsy therapy during the remaining gestation and its local impact on fetal development. Five ewes (six lambs) at 95-107 d of gestation were treated and allowed to complete the full gestation period of 150 d. A 1-MHz focused transducer was used to treat the fetal kidney and liver with 5-µs pulses at 500-Hz repetition rates and 10- to 16-MPa peak negative pressures; ultrasound imaging provided real-time treatment guidance. The lambs were euthanized after delivery and treated organs were harvested. Samples were examined by magnetic resonance imaging and histopathologic analysis. These data were compared with results from four other ewes (four lambs) that underwent similar treatments but were sacrificed immediately after the procedure. The sheep tolerated the treatment well, and acute lesion samples displayed well-defined ablated regions characterized by the presence of fractionated tissue and hemorrhage. All fetuses that were allowed to continue gestation survived and were delivered at full term. The lambs were healthy on delivery, with no signs of external injury. A minor indentation was observed in each of the treated kidneys with minimal presence of fibrous tissue, while no discernible signs of lesions were detected in treated livers. In a sheep model, histotripsy-mediated fetal tissue ablation caused no acute or pregnancy-related complications, supporting the potential safety and effectiveness of histotripsy therapy as a tool in fetal intervention procedures.

Reevaluating the sonographic criteria for acute appendicitis in children: a review of the literature and a retrospective analysis of 246 cases.

RATIONALE AND OBJECTIVES: There has been little rigorous evaluation of the sonographic criteria for acute appendicitis in children. Our clinical experience has called the traditional diagnostic criteria into question. We set out to review the literature, evaluate the most commonly applied diagnostic criteria for acute appendicitis, and identify those criteria that best predict the presence of disease. MATERIALS AND METHODS: A critical review of the literature concerning the sonographic diagnosis of acute appendicitis was performed. Based on diagnostic criteria identified in that review, two independent, blinded pediatric radiologists retrospectively reviewed 246 right lower quadrant ultrasound examinations in which the appendix was identified with attention to commonly described diagnostic criteria for acute appendicitis. Multivariate and classification and regression tree analysis were performed to identify criteria that predict appendicitis. RESULTS: In a multivariate analysis, inflammation of the periappendiceal fat is the only finding that statistically significantly predicts acute appendicitis (OR = 68.93, P < .0001). Other criteria such as diameter, noncompressibility, hyperemia, the presence of an appendicolith, and loss of stratification of the appendiceal wall do not independently predict appendicitis. CONCLUSION: Periappendiceal fat infiltration is the most important diagnostic criterion for acute appendicitis in children. Strict application of other criteria such as diameter should be avoided.

A critical evaluation of US for the diagnosis of pediatric acute appendicitis in a real-life setting: how can we improve the diagnostic value of sonography?

BACKGROUND: We have observed that day-to-day use of US for acute appendicitis does not perform as well as described in the literature. OBJECTIVE: Review the diagnostic performance of US in acute appendicitis with attention to factors that influence performance. MATERIALS AND METHODS: Retrospective review of all sonograms for acute appendicitis in children from May 2005 to May 2010 with attention to the rate of identification of the appendix, training of personnel involved and diagnostic accuracy. RESULTS: The appendix was identified in 246/1,009 cases (24.4%), with identification increasing over time. The accuracy of US was 85-91% with 35 false-positives and 54 false-negatives. Pediatric sonographers were significantly better at identifying the appendix than non-pediatric sonographers (P < 0.0001). Increased weight was the only patient factor that influenced identification of the appendix (P = 0.006). CT use was stable over the 5 years but declined in cases where the appendix was identified by US. CONCLUSION: In day-to-day use, US does not perform as purported in the literature. We do not visualize the appendix as often as we should and false-negative and false-positive exams are too common. To improve the diagnostic performance of this modality, involvement by experienced personnel and/or additional training is needed.

CT and MRI appearances and radiologic staging of pediatric renal cell carcinoma.

BACKGROUND: Renal cell carcinoma (RCC) is an uncommon but noteworthy primary pediatric renal malignancy. There is a paucity of published data regarding the CT/MRI appearances and accuracy of pretreatment radiologic staging of this form of cancer in children. OBJECTIVE: To review the various CT/MRI appearances of pediatric RCC and assess the accuracy of pretreatment radiologic staging using these imaging modalities. MATERIALS AND METHODS: Institutional Departments of Pathology and Radiology records were searched from 1995 through 2010 for children (younger than 18 years of age) with RCC. Available pretreatment contrast-enhanced abdominopelvic CT and MRI examinations were reviewed by two radiologists. Pertinent imaging findings were documented by consensus, and correlation was made between radiologic and surgicopathological TNM staging. RESULTS: Pretreatment imaging studies from 10 RCCs in nine children (four girls and five boys; mean age 12.9 years) were reviewed. The mean size of the primary tumor was 6.2 cm (range, 1.5-12.6 cm). Ninety percent of RCCs demonstrated heterogeneous postcontrast enhancement. Fifty percent of masses had associated hemorrhage, while 40% contained internal calcification. Regarding TNM staging, N staging was correct for 10 of 10 tumors, while M staging was correct for 10 of 10 tumors. Imaging correctly staged only 4 of 10 tumors with respect to T stage. Radiologic and surgicopathological overall staging were concordant for 8 of 10 tumors. CONCLUSION: Pediatric RCCs typically present as large, heterogeneous masses, and they commonly hemorrhage and contain internal calcification. Radiologic and surgicopathological overall TNM staging are frequently concordant, although radiologic T staging is often incorrect.

MR enterography of perforated acute Meckel diverticulitis.

Meckel diverticulum is the most common congenital anomaly of the small intestine that generally comes to attention due to a variety of complications, such as gastrointestinal tract bleeding, bowel obstruction or acute inflammation. These diverticula frequently are difficult to prospectively diagnose by imaging. Clinically, acute Meckel diverticulitis can be mistaken for acute appendicitis or Crohn disease. We present a 6-year-old boy with perforated acute Meckel diverticulitis that mimicked Crohn disease both clinically and by CT imaging and was definitively diagnosed using MR enterography.

Gastrointestinal tumors in children.

Although tumors arising from the spleen, pancreas, and gastrointestinal tract in the pediatric population are relatively uncommon, imaging plays an important role in diagnosis, staging, and treatment planning. Initial imaging with abdominal radiograph contributes to the evaluation for intestinal obstruction, constipation, and mass effect, and sometimes may reveal areas of calcification.

Comparison of MR enterography and histopathology in the evaluation of pediatric Crohn disease.

BACKGROUND: While MR enterography (MRE) is commonly used to identify segments of bowel affected by Crohn disease in children, there is little data to support this practice. OBJECTIVE: To assess the ability of MRE to identify segments of small bowel and colon affected by pediatric Crohn disease using histopathology as the reference standard. MATERIALS AND METHODS: Pediatric MRE examinations performed between April 2009 and December 2010 were identified. Subjects were excluded if they did not have Crohn disease, if they had Crohn disease but no correlative histopathology within 2 months of imaging, or if they had undergone prior bowel resection. Pertinent MRE and histopathology reports were reviewed, and normal and abnormal bowel segments were documented. RESULTS: Thirty-two pediatric MRE examinations were identified with correlative histopathology. MRE had an overall sensitivity of 94% for detecting the presence of Crohn disease, in general. At the bowel segmental level, MRE had a sensitivity of 66%, specificity of 90%, positive predictive value of 85% and negative predictive value of 76%. The terminal ileum was abnormal by MRE in 11 of 15 (73%) subjects lacking a diagnostic biopsy of this bowel segment. CONCLUSION: MRE successfully identifies small bowel and colon segments affected by pediatric Crohn disease.

Expanding upon the unilateral hyperlucent hemithorax in children.

Unilateral hyperlucent hemithorax is a common pediatric chest radiographic finding that may also be seen at computed tomography. It may result from congenital or acquired conditions involving the pulmonary parenchyma, airway, pulmonary vasculature, pleural space, and chest wall, as well as from technical factors such as patient rotation. Unilateral hyperlucent hemithorax has a broad differential diagnosis that includes unilateral emphysematous or bullous disease, pneumatocele, foreign body aspiration, Swyer-James syndrome, congenital lobar emphysema, endobronchial mass, unilateral pulmonary agenesis, proximal interruption of the pulmonary artery, scimitar syndrome, diaphragmatic hernia, and Poland syndrome. Although certain causes of unilateral hyperlucent hemithorax are clinically significant and potentially life threatening, others are of minimal or no clinical significance. When evaluating a patient with this finding, it is important to establish whether the apparent unilateral hyperlucent hemithorax is truly too lucent (hypoattenuating) or if the contralateral hemithorax is too opaque (hyperattenuating). It is imperative that radiologists be aware of the various causes of unilateral hyperlucent hemithorax so that they may diagnose the underlying condition and appropriately guide patient management.

MR enterography of ileocolovesicular fistula in pediatric Crohn disease.

Crohn disease, a form of chronic inflammatory bowel disease is characterized by discontinuous inflammatory lesions of the gastrointestinal tract, has a variety of behavioral patterns, including penetrating or fistulous disease. While magnetic resonance enterography (MRE) excellently depicts inflamed bowel segments, it can also be used to assess for a variety of Crohn-disease-related extraintestinal complications, including fistulae. We present the MRE findings of a complex ileocolovesicular fistula in a 14-year-old boy with Crohn disease, where the fistulous tract to the urinary bladder was best delineated on precontrast T1-W imaging because of the presence of fecal material.

Breast fibroadenomas in the pediatric population: common and uncommon sonographic findings.

BACKGROUND: Sonography is usually requested to evaluate palpable pediatric breast lumps, and solid masses are almost always fibroadenomas. Lack of familiarity with the findings of fibroadenomas can lead to diagnostic uncertainty and sometimes unnecessary biopsy and excision. We sought to review the spectrum of sonographic findings in our cases of pathology proven pediatric fibroadenomas. OBJECTIVE: The purpose of this retrospective study was to describe the sonographic appearances of pathologically proven pediatric breast fibroadenomas. MATERIALS AND METHODS: A query of the Department of Radiology database at our institution was performed for all patients younger than 19 years who underwent breast US from January 2001 to June 2009. A total of 332 patients were identified: 282 girls (85%) and 50 boys (15%). Ninety-one girls and no boys had a solid breast mass based on US findings. Forty-three children had a total of 49 pathologically proven breast masses with the diagnoses of fibroadenoma (44), hamartoma (1), non-Hodgkin lymphoma (1), tubular adenoma (1), pseudoangiomatous stromal hyperplasia (1) and lactation changes (1). Reviews of medical records, histological results and sonographic examinations of all pathology-proven fibroadenomas were performed. US findings were characterized according to location, multiplicity, size, shape, echogenicity and homogeneity, definition of margins, posterior acoustic features and Doppler vascularity. RESULTS: The vast majority of solid breast masses in girls are histologically benign. Fibroadenomas accounted for 91% of the pathologically proven solid breast masses. Common findings on US imaging are an oval shape, hypoechoic echo pattern, posterior acoustic enhancement and internal Doppler signal. Lobulations were found in 57% of the masses. Less common findings are absent internal vascular flow and complex echo pattern, while isoechoic echo pattern, posterior shadowing and angular margins are rare or unusual. CONCLUSION: Fibroadenomas represent the most common solid mass in the breasts of girls. Sonographic appearances are usually characteristic and do not significantly differ from those found in adults. The radiologist must be aware of common and uncommon sonographic appearances of fibroadenomas in the pediatric age group and should be cautious when recommending histological confirmation based on imaging findings, as breast malignancy is extremely rare.