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Background: Selection of the most appropriate sonographic scanning approaches for evaluation of hips can improve the method efficacy and decrease the scanning time.Objective: To determine the sonographic scanning planes that best assess the proximal femoral vascularity in asymptomatic and pathologic hips of children with Legg-Calvé-Perthes disease (LCPD) and evaluate the frequency (number of hips with evidence of perfusion) and intensity (number of color pixels per region) of color pixels representing superficial cartilaginous and deep transphyseal vascularity in different anatomic regions of pathologic and asymptomatic hips using multipositional power Doppler approaches.Materials and Methods: Seven scanning approaches (anterior-sagittal, anterior-transverse, coronal, adduction, perineal, 30 degrees and 70 degrees of abduction) were applied in 26 pathologic hips of 26 children with LCPD (age range 3-11 years) and in 25 contralateral asymptomatic hips. The color Doppler signals seen within the proximal femur were analyzed both qualitatively (overall/regional frequency) and quantitatively (intensity).Results: The coronal (P=0.009) and 30 degrees abduction (P=0.047) approaches demonstrated a higher frequency of color pixels in pathologic than in asymptomatic hips. The anterior-sagittal, 30 degrees abduction, adduction and anterior-transverse planes performed best of all approaches (P=0.02) to assess deep transphyseal perfusion. The physis demonstrated a greater intensity of color signals representing intraosseous vascularity than other regions in pathologic hips (P=0.027), as noted with the anterior-sagittal approach. There was a tendency (P=0.06) towards a greater intensity of pixels representing cartilaginous vascularity in pathologic hips' physes with the coronal approach.Conclusion: Specific sonographic scanning planes are recommended for assessment of the proximal femoral vascularity of LCPD hips. The physis is the anatomic region that presents with the greatest intensity of color signals in pathologic hips. [ABSTRACT FROM AUTHOR]

Background: Individual ultrasound (US) features have limited ability to distinguish benign from malignant thyroid nodules. Adult-based systems have been developed to integrate the sonographic features in an effort to improve diagnostic accuracy. None, however, has been validated in children, in whom the likelihood of malignancy is 2-5 times higher than adults., Objective: To assess the performance of two adult-based sonographic (US) stratification methods for assessment of thyroid nodules in children., Materials and Methods: This retrospective study comprised 124 children who underwent thyroid US. Three radiologists reviewed the US data using the American Thyroid Association (ATA) and the Thyroid Image Reporting and Data System (TI-RADS). Radiologists' accuracy and agreement was assessed. The reference standard was histopathology/cytology or 2-year follow-up of clinical outcome for nonoperative cases., Results: We assessed 71 benign and 52 malignant nodules and excluded 1 nodule. Using the ATA pattern descriptions, 80% of malignant nodules were classified as "high" 36/52 (69%) or "intermediate" 6/52 (11%) likelihood of malignancy. A total of 20/71 (28%) benign nodules were also classified within these two categories. Using the TI-RADS, malignant nodules were classified as 2, 3, 4a, 4b, 4c and 5, with rate of malignancy of 0%, 0%, 7/52 (13.5%), 7/52 (13.5%), 32/52 (61.5%) and 6/52 (11.5%), respectively. Benign nodules were also classified in the 4a (26/71; 36.6%), 4b (17/71; 24%), 4c (14/71; 19.7%) and 5 (1/71; 1.4%) categories. The positive and negative predictive values were 68.0% and 87.5% for ATA, and 71.7% and 80.0% for TI-RADS., Conclusion: We validated the use of ATA and TI-RADS methods in children and showed that they have test characteristics similar to those in adults, although neither is independently sufficient to discriminate nodules' likelihood of malignancy.

Background: Safety concerns are increasingly raised regarding the use of gadolinium-based contrast media for MR imaging., Objective: To determine the accuracy of pre-contrast abdominal MR imaging for lesion detection and characterization in pediatric oncology patients., Materials and Methods: We included 120 children (37 boys and 83 girls; mean age 8.94 years) referred by oncology services. Twenty-five had MRI for the first time and 95 were follow-up scans. Two authors independently reviewed pre-contrast MR images to note the following information about the lesions: location, number, solid vs. cystic and likely nature. Pre- and post-contrast imaging reviewed together served as the reference standard., Results: The overall sensitivity was 88% for the first reader and 90% for the second; specificity was 94% and 91%; positive predictive value was 96% and 94%; negative predictive value was 82% and 84%; accuracy of pre-contrast imaging for lesion detection as compared to the reference standard was 90% for both readers. The difference between mean number of lesions detected on pre-contrast imaging and reference standard was not significant for either reader (reader 1, P = 0.072; reader 2, P = 0.071). There was substantial agreement (kappa values of 0.76 and 0.72 for readers 1 and 2) between pre-contrast imaging and reference standard for determining solid vs. cystic lesion and likely nature of the lesion. The addition of post-contrast imaging increased confidence of both readers significantly (P < 0.0001), but the interobserver agreement for the change in confidence was poor (kappa 0.12)., Conclusion: Pre-contrast abdominal MR imaging has high accuracy in lesion detection in pediatric oncology patients and shows substantial agreement with the reference standard for characterization of lesions. Gadolinium-based contrast media administration cannot be completely eliminated but can be avoided in many cases, with the decision made on a case-by-case basis, taking into consideration location and type of tumor.

Background: The position of the tip of a peripherally inserted central catheter (PICC) is crucial; malposition can lead to malfunction of the line or life-threatening events (e.g., arrhythmias, perforation)., Objective: To determine what factors other than arm position and accessed vein might influence the tip position of a PICC., Materials and Methods: Inclusion criteria were upper limb PICC placement, body weight <20 kg, intraoperative imaging with the arm in 0°, 45° and 90° abduction and an arm view marking the skin entry site relative to the shoulder. Evaluated variables included patient demographics, and PICC and insertion site characteristics. We measured central tip movement in rib units., Results: We included 112 children who received a PICC (42 girls/70 boys, mean age 31±13 months, mean weight 6.5±4.9 kg). The overall range of central tip movement was -1 to +4 rib units (mean +0.8±0.7 rib units). Silicone PICCs moved significantly less than polyurethane PICCs (P<0.05). PICCs placed in the cephalic vein moved significantly less than those placed in other veins (P<0.05). Patient demographics and PICC characteristics (size, number of lumens, left or right arm accessed, length of the line) did not influence the range of central tip movement of a PICC (P>0.05)., Conclusion: Silicone PICCs and PICCs inserted into the cephalic vein move less than PICCs made of polyurethane and PICCs inserted into the brachial and basilic veins. These findings might assist operators in deciding which PICC to place in children in a given clinical context.

Background: There are no studies on utility of MRI in management of pediatric adnexal masses., Objective: To determine the diagnostic and therapeutic impact of pelvic MRI in adnexal masses in children and adolescents., Materials and Methods: We included 32 females age 18 years and younger who had adnexal masses and who underwent both pelvic ultrasound (US) and MRI. A radiologist retrospectively reviewed US and MR images and created a standard radiologic report for each patient. In a prospective theoretical fashion, two pediatric gynecologists reviewed the clinical data and US report for each patient and indicated conservative versus surgical management; in surgical cases the options were laparoscopy versus laparotomy, midline versus Pfannenstiel incision, and oophorectomy versus cystectomy. Subsequently, the gynecologists were presented the MRI report and were asked to indicate their treatment options again. A binomial test was conducted to determine the effect of adding MRI findings to the management plan., Results: The addition of MRI significantly changed management in 10 of 32 patients (P=0.0322), with a change in surgical versus conservative treatment in 5, a change in laparotomy vs. laparoscopy in 2, and a change from oophorectomy to cystectomy along with change in incision in 3 cases. This was based on additional information provided by MRI regarding the nature of the mass in 8 cases and origin of the mass in 2 cases., Conclusion: Preoperative pelvic MRI findings might change the surgical management of pediatric patients with adnexal masses, so it is a valuable addition to the conventional workup in the clinical management.

Background: Dual-energy absorptiometry (DXA) is the current reference standard for assessing pediatric osteoporosis; however due to its areal nature, it has limitations. Thus, quantitative ultrasound (QUS), a modality free of ionizing radiation, has been proposed as a potential surrogate for DXA., Objective: To semi-quantitatively assess the diagnostic accuracy of QUS for evaluating pediatric osteoporosis according to the U.S. Preventive Services Task Force guidelines., Materials and Methods: We retrieved articles on the diagnostic accuracy of quantitative US for assessing abnormal bone quality or quantity in patients of mean age ≤19 years from MEDLINE, EMBASE and Cochrane Library CCTR databases. Evidences were analyzed for reliability, construct and criterion validity, and responsiveness of quantitative US, according to the following questions: (1) How reliable is the acquisition of QUS measurements? (2) Is QUS diagnostically accurate to characterize bone strength and quality in osteoporotic children? (3) Is QUS sensitive to detect changes in bone status over time? (4) Is QUS able to predict future skeletal fractures/degeneration? Three reviewers independently evaluated the quality of reporting and methodological quality using the Standards for Reporting of Diagnostic Accuracy (STARD) and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tools., Results: Out of 262 retrieved references (215 unique), we included 28 studies (1,963 patients; 807 reported boys and 761 girls, others unspecified; reported mean age, 0-19 years). The mean quality of reporting score was "excellent" in 24/28 (86%) studies; 11/28 (39%) studies had "adequate" research design quality., Conclusion: There is no evidence of the diagnostic value of QUS at the present time despite the overall excellent and adequate research design quality of primary studies. Although QUS can produce reliable measurements, insufficient evidence has been reported to support other clinimetric properties of this technique.

Background: Radiologic insertion of a gastrostomy or gastrojejunostomy tube is a common procedure in children. Glucagon is used to create gastric hypotonia, permitting gastric distension and facilitating percutaneous puncture. Glucagon can cause hyperglycaemia and potentially rebound hypoglycaemia. The safety of glucagon and incidence of hypoglycaemia has not been studied following gastrostomy or gastrojejunostomy tube insertion., Objective: To determine variations in blood glucose in children post gastrostomy or gastrojejunostomy tube insertion. Secondarily, to determine the frequency of hypoglycaemia and hyperglycaemia in children who did or did not receive glucagon., Materials and Methods: This is a retrospective observational study of 210 children undergoing percutaneous gastrostomy or gastrojejunostomy tube insertion over a 2-year period. We studied the children's clinical and laboratory parameters. Abnormal blood glucose levels were defined according to age-established norms. We used descriptive statistics and ANOVA., Results: We analysed 210 children with recorded blood glucose levels. More than 50% of the children were less than the third percentile for weight. In the glucagon group (n = 187) hyperglycaemia occurred in 82.3% and hypoglycaemia in 2.7% (n = 5). In the no glucagon group (n = 23), hyperglycaemia occurred in 43.5% and there were no cases of hypoglycaemia. The peak blood glucose occurred within 2 h, with normalization by 6 h post-procedure. Five children became hypoglycaemic, all received glucagon; 4/5 had weights <3rd percentile. Logistic regression analysis revealed no factors significantly associated with hypoglycaemia., Conclusion: Greatest blood glucose variability occurs between 1 h and 3 h post-procedure. Hyperglycaemia is common and more severe with glucagon, and hypoglycaemia rarely occurs. These findings have assisted in developing clinical guidelines for post-percutaneous gastrostomy/gastrojejunostomy tube insertion.

Background: Recent advances in hemophilia prophylaxis have raised the need for accurate noninvasive methods for assessment of early cartilage damage in maturing joints to guide initiation of prophylaxis. Such methods can either be semiquantitative or quantitative. Whereas semiquantitative scores are less time-consuming to be performed than quantitative methods, they are prone to subjective interpretation., Objective: To test the feasibility of a manual segmentation and a quantitative methodology for cross-sectional evaluation of articular cartilage status in growing ankles of children with blood-induced arthritis, as compared with a semiquantitative scoring system and clinical-radiographic constructs., Materials and Methods: Twelve boys, 11 with hemophilia (A, n = 9; B, n = 2) and 1 with von Willebrand disease (median age: 13; range: 6-17), underwent physical examination and MRI at 1.5 T. Two radiologists semiquantitatively scored the MRIs for cartilage pathology (surface erosions, cartilage loss) with blinding to clinical information. An experienced operator applied a validated quantitative 3-D MRI method to determine the percentage area of denuded bone (dAB) and the cartilage thickness (ThCtAB) in the joints' MRIs. Quantitative and semiquantitative MRI methods and clinical-radiographic constructs (Hemophilia Joint Health Score [HJHS], Pettersson radiograph scores) were compared., Results: Moderate correlations were noted between erosions and dAB (r = 0.62, P = 0.03) in the talus but not in the distal tibia (P > 0.05). Whereas substantial to high correlations (r range: 0.70-0.94, P < 0.05) were observed between erosions, cartilage loss, HJHS and Pettersson scores both at the distal tibia and talus levels, moderate/borderline substantial (r range: 0.55-0.61, P < 0.05) correlations were noted between dAB/ThCtAB and clinical-radiographic constructs., Conclusion: Whereas the semiquantitative method of assessing cartilage status is closely associated with clinical-radiographic scores in cross-sectional studies of blood-induced arthropathy, quantitative measures provide independent information and are therefore less applicable for that research design.

Background: Blood-oxygen-level-dependent (BOLD) MRI has the potential to identify regions of early hypoxic and vascular joint changes in inflammatory arthritis. There is no standard protocol for analysis of BOLD MRI measurements in musculoskeletal disorders., Objective: To optimize the following BOLD MRI reading parameters: (1) statistical threshold values (low, r > 0.01 versus high, r > 0.2); (2) summary measures of BOLD contrast (percentage of activated voxels [PT%] versus percentage signal difference between on-and-off signal intensities [diff&#95;on&#95;off]); and (3) direction of BOLD response (positive, negative and positive + negative)., Materials and Methods: Using BOLD MRI protocols at 1.5 T, arthritic (n = 21) and contralateral (n = 21) knees of 21 juvenile rabbits were imaged at baseline and on days 1, 14 and 28 after a unilateral intra-articular injection of carrageenan. Nine non-injected rabbits served as external control knees (n = 18). By comparing arthritic to contralateral knees, receiver operating characteristic curves were used to determine diagnostic accuracy., Results: Using diff&#95;on&#95;off and positive + negative responses, a threshold of r > 0.01 was more accurate than r > 0.2 (P = 0.03 at day 28). Comparison of summary measures yielded no statistically significant difference (P > 0.05). Although positive + negative (AUC = 0.86 at day 28) and negative responses (AUC = 0.90 at day 28) for PT% were the most diagnostically accurate, positive + negative responses for diff&#95;on&#95;off (AUC = 0.78 at day 28) also had acceptable accuracy., Conclusions: The most clinically relevant reading parameters included a lower threshold of r > 0.01 and a positive + negative BOLD response. We propose that diff&#95;on&#95;off is a more clinically relevant summary measure of BOLD MRI, while PT% can be used as an ancillary measure.

Background: No study reported in the literature comprehensively compares findings on neonatal abdominal radiographs with sonography., Objective: To compare the findings on abdominal radiographs and sonograms in infants in intensive care, to better understand how the various intestinal gas patterns on radiographs relate to the spectrum of appearances on sonography and, second, to evaluate the ability of sonography to differentiate necrotizing enterocolitis from other intestinal pathology., Materials and Methods: We prospectively evaluated sonograms and radiographs, blinded to the other modality and to clinical information. Patients' charts were reviewed by a third blinded reader and used as a reference standard for diagnosis. We made associations between sonographic findings, radiographic intestinal gas patterns and clinical diagnoses., Results: We included 75 infants with gestational ages between 23 weeks and 41 weeks. Sonographic abnormalities were present in infants with all radiographic intestinal gas patterns, including normal patterns. We only saw absent intestinal perfusion and fluid collections on sonography (suggesting intestinal necrosis and sealed perforation) in infants with intestinal dilatation with elongation on radiographs. Separation of intestinal loops on radiographs was most commonly caused by reasons other than intestinal wall thickening. Increased intestinal echogenicity or free fluid with echoes on sonography correlated with a diagnosis of necrotizing enterocolitis, whereas anechoic free fluid correlated with absence of necrotizing enterocolitis., Conclusion: Sonography is complementary to radiographs in infants with suspected intestinal pathology, with a spectrum of appearances seen on each modality. Some sonographic findings either strongly suggest necrotizing enterocolitis or supply evidence against this diagnosis.

Background: The two most commonly performed magnetic resonance cholangiopancreatography (MRCP) sequences, 3-D fast spin-echo (3-D FSE) and single-shot fast spin-echo radial slabs (radial slabs), have not been compared in children., Objective: The purpose of this study was to compare 3-D FSE and radial slabs MRCP sequences on a 3-T scanner to determine their ability to show various segments of pancreaticobiliary tree and presence of artifacts in children., Materials and Methods: We reviewed 79 consecutive MRCPs performed in 74 children on a 3-T scanner. We noted visibility of major ducts on 3-D FSE and radial slabs. We noted the order of branching of ducts in the right and left hepatic ducts and the degree of visibility of the pancreatic duct. Statistical analysis was performed using McNemar and signed rank tests., Results: There was no significant difference in the visibility of major bile ducts and the order of branching in the right hepatic lobe between sequences. A higher order of branching in the left lobe was seen on radial slabs than 3-D FSE (mean order of branching 2.82 versus 2.27; P-value = 0.0002). The visibility of pancreatic duct was better on radial slabs as compared to 3-D FSE (mean value of 1.53 vs. 0.90; P-value < 0.0001). 3-D FSE sequence was artifact-free in 25/79 (31.6%) MRCP exams as compared to radial slabs, which were artifact-free in 18/79 (22.8%) MRCP exams (P-value = 0.0001)., Conclusion: There is no significant difference in the visibility of major bile ducts between 3-D FSE and radial slab MRCP sequences at 3-T in children. However, radial slab MRCP shows a higher order of branching in the left hepatic lobe and superior visibility of the pancreatic duct than 3-D FSE.

Background: Color Doppler US (CDUS) has been used for evaluation of cerebral venous sinuses in neonates. However, there is very limited information available regarding the appearance of superficial and deep normal cerebral venous sinuses using CDUS and the specificity of the technique to rule out disease., Objective: To determine the specificity, inter-modality and inter-reader agreement of color Doppler US (CDUS). To evaluate normal cerebral venous sinuses in neonates in comparison to MR venography (MRV)., Materials and Methods: Newborns undergoing a clinically indicated brain MRI were prospectively evaluated. All underwent a dedicated CDUS of the cerebral venous sinuses within 10 h (mean, 3.5 h, range, and 2-7.6 h) of the MRI study using a standard protocol., Results: Fifty consecutive neonates participated in the study (30 males [60%]; 25-41 weeks old; mean, 37 weeks). The mean time interval between the date of birth and the CDUS study was 19.1 days. No cases showed evidence of thrombosis. Overall agreement for US reading was 97% (range, 82-100%), for MRV reading, 99% (range, 96-100%) and for intermodality, 100% (range, 96-100%). Excellent US-MRI agreement was noted for superior sagittal sinus, cerebral veins, straight sinus, torcular Herophili, sigmoid sinus, superior jugular veins (94-98%) and transverse sinuses (82-86%). In 10 cases (20%), MRV showed flow gaps whereas normal flow was demonstrated with US. Visualization of the inferior sagittal sinus was limited with both imaging techniques., Conclusion: Excellent reading agreement was noted for US, MRV and intermodality. CDUS is highly specific to rule out cerebral venous thrombosis in neonates and holds potential for clinical application as part of clinical-laboratory-imaging algorithms of pre/post-test probabilities of disease.

Background: Because of the ability of blood-oxygen-level-dependent (BOLD) MRI to assess blood oxygenation changes within the microvasculature, this technique holds potential for evaluating early perisynovial changes in inflammatory arthritis., Objective: To evaluate the feasibility of BOLD MRI to detect interval perisynovial changes in knees of rabbits with inflammatory arthritis., Materials and Methods: Rabbit knees were injected with albumin (n=9) or saline (n=6) intra-articularly, or were not injected (control knees, n=9). Except for two rabbits (albumin-injected, n=2 knees; saline-injected, n=2 knees) that unexpectedly died on days 7 and 21 of the experiment, respectively, all other animals were scanned with BOLD MRI on days 0, 1, 7, 14, 21 and 28 after induction of arthritis. T2*-weighted gradient-echo MRI was performed during alternate 30 s of normoxia/hyperoxia. BOLD MRI measurements were compared with clinical, laboratory and histological markers., Results: Percentage of activated voxels was significantly greater in albumin-injected knees than in contralateral saline-injected knees (P=0.04). For albumin-injected knees (P<0.05) and among different categories of knees (P=0.009), the percentage of activated BOLD voxels varied over time. A quadratic curve for on-and-off BOLD difference was delineated for albumin- and saline-injected knees over time (albumin-injected, P=0.047; saline-injected, P=0.009). A trend toward a significant difference in synovial histological scores between albumin-injected and saline-injected knees was noted only for acute scores (P=0.07)., Conclusion: As a proof of concept, BOLD MRI can depict perisynovial changes during progression of experimental arthritis.

Background: Studies have reported that thoracic CT may provide greater sensitivity compared with radiography in detection of pediatric rib fractures and fracture healing. The additional sensitivity afforded by thoracic CT may have medicolegal implications where abuse is suspected., Objective: To determine the additional value of postmortem thoracic CT compared with radiography in detecting pediatric rib fractures, and fracture healing, using autopsy findings as a gold standard., Materials and Methods: We retrospectively reviewed 56 coroner's cases with postmortem radiography and CT thoracic survey. All studies underwent primary interpretation by one or two radiologists. The study radiologist independently reviewed all images from 13 patients with positive findings on radiography, CT or autopsy. Sensitivity and specificity between observers and imaging modalities were compared., Results: Primary interpretation: Fractures were recognized on radiography in 5/12 patients who had fractures found at autopsy, and on CT in 8/12 patients. In total, 29% (24/83) of fractures were reported on radiography, and 51% (52/101) of fractures were reported on CT. Study radiologist: Fractures were recognized on radiography in 7/12 patients who had fractures found at autopsy, and on CT in 11/12 patients. In total, 46% (38/83) of fractures were reported on radiography, and 85% (86/101) of fractures were reported on CT., Conclusion: Postmortem thoracic CT provides greater sensitivity than radiography in detecting pediatric rib fractures, most notably in anterior and posterior fractures. However, the degree of improvement in sensitivity provided by CT might depend on observer experience.

Background: Incidental thyroid abnormalities detected on US examinations in children have not been well documented., Objective: To determine prevalence of incidental thyroid abnormalities depicted by US in children and to describe the spectrum of appearances., Materials and Methods: Retrospective analysis of clinical and US findings in children who had neck US from January 2006 to December 2007., Results: Of 1,228 neck US exams, thyroid was depicted in 287 children (mean age = 6.2 years). Incidental thyroid abnormalities were detected in 52 (18%) (mean age = 8.1 years). In 35 there were small (<4 mm), well-defined cysts, some with a hyperechoic punctate focus. In nine there were hypoechoic, solid nodules with smooth, straighter margins with echogenicity similar to thymus, suggesting intrathyroid ectopic thymus (mean age = 2.5 years). In three others there were tiny hyperechoic foci without nodules. Other abnormalities included hypoechoic target-like lesions (n = 2), isoechoic nodule (n = 1), multiple hypoechoic foci (n = 1) and non-visualized thyroid lobe resulting from adjacent abscess (n = 1). None of the children developed thyroid dysfunction or malignancy., Conclusion: There is a spectrum of incidental thyroid abnormalities in children. These US findings should be interpreted cautiously, avoiding unnecessary referrals and investigations. Intrathyroid ectopic thymus is more common than previously thought, occurs much more frequently in younger boys and should be considered if the lesion has US characteristics of thymus.

Background: Head US, the cornerstone neuroimaging modality in neonates, is believed to be less sensitive than MRI for detecting hypoxic ischemic injury (HII). Most reports comparing these modalities are retrospective and have a long interval between the exams., Objective: To prospectively characterize the range of abnormalities found in US examinations performed within 2 h of brain MRI in encephalopathic neonates., Materials and Methods: A total of 76 consecutive exams met our inclusion criteria. Diagnostic performance of the US images was prospectively compared with MRI., Results: MRI was considered positive for HII in 53 neonates. Of the remaining 23, MRI was negative for HII in 9, showed white matter abnormalities unrelated to HII in 8, and was inconclusive in 6. Of the 70 neonates with conclusive examinations, the US exam was regarded as positive in 67. Diagnostic accuracy of US was 95.7%., Conclusion: Our study demonstrates that US should still be regarded as a screening test in neonates. US is more sensitive for the detection of injury than previously reported, and more attention should be paid to proper US technique. MRI shows disease more extensively and should be accomplished as early as possible.

Background: Parallel imaging provides faster scanning at the cost of reduced signal-to-noise ratio (SNR) and increased artifacts., Objective: To compare the diagnostic performance of two parallel MRI protocols (PPs) for assessment of pathologic knees using an 8-channel knee coil (reference standard, conventional protocol [CP]) and to characterize the SNR losses associated with parallel imaging., Materials and Methods: Two radiologists blindly interpreted 1.5 Tesla knee MRI images in 21 children (mean 13 years, range 9-18 years) with clinical indications for an MRI scan. Sagittal proton density, T2-W fat-saturated FSE, axial T2-W fat-saturated FSE, and coronal T1-W (NEX of 1,1,1) images were obtained with both CP and PP. Images were read for soft tissue and osteochondral findings., Results: There was a 75% decrease in acquisition time using PP in comparison to CP. The CP and PP protocols fell within excellent or upper limits of substantial agreement: CP, kappa coefficient, 0.81 (95% CIs, 0.73-0.89); PP, 0.80-0.81 (0.73-0.89). The sensitivity of the two PPs was similar for assessment of soft (0.98-1.00) and osteochondral (0.89-0.94) tissues. Phantom data indicated an SNR of 1.67, 1.6, and 1.51 (axial, sagittal and coronal planes) between CP and PP scans., Conclusion: Parallel MRI provides a reliable assessment for pediatric knees in a significantly reduced scan time without affecting the diagnostic performance of MRI.

Background: Improvement in resolution and use of high-frequency transducers in US has enabled visualization of previously unreported changes in medullary pyramid echogenicity in children with obstructive hydronephrosis., Objective: To determine whether these unreported changes in echogenicity and morphology of the renal pyramids in ureteropelvic junction (UPJ) obstruction correlate with differential renal function (DRF) of the kidney as determined by technetium-99m mercaptoacetyltriglycine ((99m)Tc-MAG3) scan., Materials and Methods: Renal sonograms in 60 children with UPJ obstruction were retrospectively reviewed. Children were divided into three groups based on the echogenicity of the pyramids: (1) normal echogenicity of the pyramids, (2) increased echogenicity of the pyramids with maintained corticomedullary differentiation (CMD), and (3) loss of CMD. DRF, as determined by (99m)Tc-MAG3 scan, of the obstructed kidney of > or =45% was considered normal and of < or =44% was considered abnormal based on a published study correlating histological changes with DRF. Fisher's exact test was performed for assessing the association between DRF and altered echogenicity of the pyramids., Results: In group 1, which consisted of 13 patients with normal pyramids on US, DRF was normal in 11 and abnormal in two. In group 2, which consisted of 33 patients with echogenic pyramids and preserved CMD, DRF was normal in 15 and abnormal in 18. In group 3, which consisted of 14 patients with complete loss of CMD, DRF was normal in 2 and abnormal in 12. There was a strong correlation between abnormal pyramids and DRF (P=0.0009). The risk ratio (RR) of DRF becoming abnormal for those kidneys with abnormal echogenicity of the pyramids with preserved CMD (group 2) compared to normal pyramid echogenicity (group 1) was 1.56 (95% CI 1.088-2.236). The RR of DRF becoming abnormal for those kidneys with loss of CMD (group 3) compared to normal pyramid echogenicity (group 1) was 5.571 (95% CI 1.530-20.294)., Conclusion: We observed that in obstructed kidneys the echogenicity of the pyramids may be abnormal. Increased echogenicity of the pyramids correlated weakly with abnormal DRF and does not necessarily indicate poor renal function. However, loss of CMD strongly correlated with poor renal function.

Background: Even when histologic findings are highly suggestive of primary sclerosing cholangitis (PSC), cholangiographic correlation is required for the diagnosis. The present gold standard, endoscopic retrograde cholangiopancreatography (ERCP), is invasive and associated with complications., Objective: To evaluate the usefulness of magnetic resonance cholangiopancreatography (MRCP) in diagnosing PSC in children., Materials and Methods: MRCP studies were retrospectively reviewed in 20 children with clinical suspicion of PSC and who had undergone liver biopsy. MRCP studies were considered positive or negative for PSC depending on the presence or absence of dilatation, irregularity, multifocal strictures and beading of the bile ducts., Results: Twenty children (14 boys, 6 girls) with an average age of 13 years qualified for the study. Of 19 diagnostic MRCP studies, 16 were called positive and 3 were called negative. An overall diagnosis of PSC-positive was assigned to all 19 patients based on clinical and laboratory findings, biopsy results and cholangiographic data. Based on this overall diagnosis, MRCP was 84% sensitive and accurate to diagnose PSC in children., Conclusion: MRCP can be a valuable tool in diagnosing pediatric PSC that can demonstrate major intra- and extrahepatic ducts in most cases. An unequivocally positive MRCP study should not be followed by ERCP for diagnosing PSC in children.

Background: There is little in the literature regarding the use of gray-scale and Doppler sonography of the bowel in necrotizing enterocolitis (NEC) and how findings depicted by this modality might assist in predicting outcome and influence management., Objective: To correlate sonographic findings with outcome in NEC., Materials and Methods: This was a retrospective analysis of clinical and abdominal ultrasonography (AUS) findings in NEC from January 2003 to December 2005. AUS findings were evaluated for portal venous gas, free gas, peritoneal fluid, bowel wall thickness, echogenicity, perfusion and intramural gas. Patients were categorized into two groups, according to their outcome., Results: A total of 40 infants were identified who had AUS for NEC prior to any surgical intervention. Group A comprised 18 neonates treated medically and recovered fully, and group B comprised 22 neonates who required surgery or died. Free gas (six patients) and focal fluid collections (three patients) were only found in group B. Increased bowel wall echogenicity, absent bowel perfusion, portal venous gas, bowel wall thinning, bowel wall thickening, free fluid with echoes and intramural gas were seen in both groups, but more frequently in group B. Anechoic free fluid was seen more frequently in group A. Increased bowel perfusion was seen equally in both groups., Conclusion: An adverse outcome was associated with the sonographic findings of free gas, focal fluid collections or three or more of the following: increased bowel wall echogenicity, absent bowel perfusion, portal venous gas, bowel wall thinning, bowel wall thickening, free fluid with echoes and intramural gas. Sonographic findings are useful in predicting outcome and therefore might help guide management.

Background: Objective quantification is critical for assessment of functional sonography in inflammatory arthritis. To create a microbubble contrast-enhanced image of vessels that lie below the resolution of a standard US system, a technique is required that detects preferentially the contrast agent echo, rejecting that from background tissue: harmonic imaging., Objectives: To investigate the ability of contrast-enhanced triggered harmonic sonography (CETHS) to evaluate periarticular hemodynamic changes over the course of experimental arthritis and to discriminate presence and absence of arthritis based on measurement values obtained at specific time-points., Materials and Methods: Arthritis was induced in rabbits knees by intra-articular injection of serum bovine albumin, which acted as an antigen. A total of 11 rabbits (8 with unilateral arthritis and 3 control animals) were imaged at 0, 1, 7, 14, 21 and 28 days of antigen-induced arthritis and euthanized at 28 days. A continuous infusion protocol was performed (triggering times 30.0, 20.0, 10.0, 5.0, 2.0, 1.0, and 0.5 s). Hemodynamic indices of synovial microvasculature (vascular volume, mean velocity and flow rate) were obtained and compared with clinical, laboratory, and histological surrogate markers., Results: Although interval CETHS changes were noted for flow rate (P=0.007) and vascular volume (P=0.003) ratios in albumin-injected knees, no significant differences in ratios were identified over time between albumin-injected and non-injected knees for flow rate (P=0.52), vascular volume (P=0.23) and mean velocity (P=0.19). Flow rate most accurately differentiated between presence and absence of arthritis according to clinical measurements in early (day 1) arthritis, and mean velocity in mid-term arthritis (day 14; both P=0.02)., Conclusion: Although the measurement properties of CETHS indices were poor in the evaluation of hemodynamic differences over time in albumin-injected knees compared with non-injected knees, they enabled discrimination between presence and absence of arthritis at specific time-points in different stages.

Background: There is increasing awareness among pediatric radiologists of the potential risks associated with ionizing radiation in medical imaging. However, it is not known whether there has been a corresponding increase in awareness among pediatricians., Objective: To establish the level of awareness among pediatricians of the recent publicity on radiation risks in children, knowledge of the relative doses of radiological investigations, current practice regarding parent/patient discussions, and the sources of educational input., Materials and Methods: Multiple-choice survey., Results: Of 220 respondents, 105 (48%) were aware of the 2001 American Journal of Roentgenology articles on pediatric CT and radiation, though only 6% were correct in their estimate of the quoted lifetime excess cancer risk associated with radiation doses equivalent to pediatric CT. A sustained or transient increase in parent questioning regarding radiation doses had been noticed by 31%. When estimating the effective doses of various pediatric radiological investigations in chest radiograph (CXR) equivalents, 87% of all responses (and 94% of CT estimates) were underestimates. Only 15% of respondents were familiar with the ALARA principle. Only 14% of pediatricians recalled any relevant formal teaching during their specialty training. The survey response rate was 40%., Conclusion: Awareness of radiation protection issues among pediatricians is generally low, with widespread underestimation of relative doses and risks.