Richard A. Barth

Prenatal Diagnosis of Placenta Accreta Sonography or Magnetic Resonance Imaging

Objective. The purpose of this study was to compare the accuracy of transabdominal sonography and magnetic resonance imaging (MRI) for prenatal diagnosis of placenta accreta. Methods. A historical cohort study was undertaken at 3 institutions identifying women at risk for placenta accreta who had undergone both sonography and MRI prenatally. Sonographic and MRI findings were compared with the final diagnosis as determined at delivery and by pathologic examination. Results. Thirty‐two patients who had both sonography and MRI prenatally to evaluate for placenta accreta were identified. Of these, 15 had confirmation of placenta accreta at delivery. Sonography correctly identified the presence of placenta accreta in 14 of 15 patients (93% sensitivity; 95% confidence interval [CI], 80%–100%) and the absence of placenta accreta in 12 of 17 patients (71% specificity; 95% CI, 49%–93%). Magnetic resonance imaging correctly identified the presence of placenta accreta in 12 of 15 patients (80% sensitivity; 95% CI, 60%–100%) and the absence of placenta accreta in 11 of 17 patients (65% specificity; 95% CI, 42%–88%). In 7 of 32 cases, sonography and MRI had discordant diagnoses: sonography was correct in 5 cases, and MRI was correct in 2. There was no statistical difference in sensitivity (P = .25) or specificity (P = .5) between sonography and MRI. Conclusions. Both sonography and MRI have fairly good sensitivity for prenatal diagnosis of placenta accreta; however, specificity does not appear to be as good as reported in other studies. In the case of inconclusive findings with one imaging modality, the other modality may be useful for clarifying the diagnosis.

Improved pediatric MR imaging with compressed sensing.

PURPOSE To develop a method that combines parallel imaging and compressed sensing to enable faster and/or higher spatial resolution magnetic resonance (MR) imaging and show its feasibility in a pediatric clinical setting. MATERIALS AND METHODS Institutional review board approval was obtained for this HIPAA-compliant study, and informed consent or assent was given by subjects. A pseudorandom k-space undersampling pattern was incorporated into a three-dimensional (3D) gradient-echo sequence; aliasing then has an incoherent noiselike pattern rather than the usual coherent fold-over wrapping pattern. This k-space-sampling pattern was combined with a compressed sensing nonlinear reconstruction method that exploits the assumption of sparsity of medical images to permit reconstruction from undersampled k-space data and remove the noiselike aliasing. Thirty-four patients (15 female and 19 male patients; mean age, 8.1 years; range, 0-17 years) referred for cardiovascular, abdominal, and knee MR imaging were scanned with this 3D gradient-echo sequence at high acceleration factors. Obtained k-space data were reconstructed with both a traditional parallel imaging algorithm and the nonlinear method. Both sets of images were rated for image quality, radiologist preference, and delineation of specific structures by two radiologists. Wilcoxon and symmetry tests were performed to test the hypothesis that there was no significant difference in ratings for image quality, preference, and delineation of specific structures. RESULTS Compressed sensing images were preferred more often, had significantly higher image quality ratings, and greater delineation of anatomic structures (P < .001) than did images obtained with the traditional parallel reconstruction method. CONCLUSION A combination of parallel imaging and compressed sensing is feasible in a clinical setting and may provide higher resolution and/or faster imaging, addressing the challenge of delineating anatomic structures in pediatric MR imaging.

Effectiveness of a Staged US and CT Protocol for the Diagnosis of Pediatric Appendicitis: Reducing Radiation Exposure in the Age of ALARA

PURPOSE To evaluate the effectiveness of a staged ultrasonography (US) and computed tomography (CT) imaging protocol for the accurate diagnosis of suspected appendicitis in children and the opportunity for reducing the number of CT examinations and associated radiation exposure. MATERIALS AND METHODS This retrospective study was compliant with HIPAA, and a waiver of informed consent was approved by the institutional review board. This study is a review of all imaging studies obtained in children suspected of having appendicitis between 2003 and 2008 at a suburban pediatric emergency department. A multidisciplinary staged US and CT imaging protocol for the diagnosis of appendicitis was implemented in 2003. In the staged protocol, US was performed first in patients suspected of having appendicitis; follow-up CT was recommended when US findings were equivocal. Of 1228 pediatric patients who presented to the emergency department for suspected appendicitis, 631 (287 boys, 344 girls; age range, 2 months to 18 years; median age, 10 years) were compliant with the imaging pathway. The sensitivity, specificity, negative appendectomy rate (number of appendectomies with normal pathologic findings divided by the number of surgeries performed for suspected appendicitis), missed appendicitis rate, and number of CT examinations avoided by using the staged protocol were analyzed. RESULTS The sensitivity and specificity of the staged protocol were 98.6% and 90.6%, respectively. The negative appendectomy rate was 8.1% (19 of 235 patients), and the missed appendicitis rate was less than 0.5% (one of 631 patients). CT was avoided in 333 of the 631 patients (53%) in whom the protocol was followed and in whom the US findings were definitive. CONCLUSION A staged US and CT imaging protocol in which US is performed first in children suspected of having acute appendicitis is highly accurate and offers the opportunity to substantially reduce radiation.

Fast pediatric 3D free-breathing abdominal dynamic contrast enhanced MRI with high spatiotemporal resolution.

To develop a method for fast pediatric 3D free‐breathing abdominal dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) and investigate its clinical feasibility.

Clinical performance of contrast enhanced abdominal pediatric MRI with fast combined parallel imaging compressed sensing reconstruction

To deploy clinically, a combined parallel imaging compressed sensing method with coil compression that achieves a rapid image reconstruction, and assess its clinical performance in contrast‐enhanced abdominal pediatric MRI.

Prenatal diagnosis of autosomal recessive polycystic kidneydisease: Variable outcome within one family

Autosomal recessive polycystic kidney disease is frequently diagnosed in utero by obstetric ultrasonography. We report a case in which there were varying outcomes of this disorder in three affected fetuses in a family. Recognition of variable expression within one family is important when parents are considering termination of a pregnancy with an affected fetus.

MR assessment of normal fetal lung volumes: A literature review

OBJECTIVE Fetal lung volume can be assessed from MR images by planimetric measurement and comparison with normal values. We review 10 MRI articles that report normal fetal lung volumes based on gestational age to assess reproducibility and application of data. CONCLUSION The articles were analyzed for differences in methodology and disparities in reported normal lung volumes by gestational age. Overall, there is substantial variability among studies regarding reported normal fetal lung volumes as measured on MRI.

MR imaging in cases of antenatal suspected appendicitis - a meta-analysis

Objective. Appendicitis is the most common surgical emergency in pregnancy. Acute appendicitis is often difficult to diagnose clinically, and concerns regarding antenatal CT imaging limit its use resulting in high false negative rates at laparotomy. MRI has recently been reported as a reasonable alternative to CT imaging in cases of suspected appendicitis. Our objective was to perform a meta-analysis of recently published data regarding the utility of MR imaging in cases of antenatal suspected acute appendicitis. Methods. We searched the PubMed database using keywords ‘MRI’, ‘appendicitis’, and ‘pregnancy’. Five case series describing the role of MRI in cases of antenatal appendicitis were included. The sensitivity, specificity, positive, and negative predictive values were calculated. Results. Two hundred twenty-nine patients were included in the study. In the first analysis in which non-diagnostic scans were excluded, the sensitivity, specificity, positive and negative predictive values of MRI for diagnosing appendicitis were 95.0%, 99.9%, 90.4%, and 99.5%, respectively. In the second analysis, which included non-diagnostic scans, the sensitivity, specificity, positive and negative predictive values were 90.5%, 98.6%, 86.3%, and 99.0%, respectively Conclusions. MR imaging may be useful in cases of suspected antenatal appendicitis. Data are still limited and larger prospective studies are necessary to confirm this finding.

Lateral meningocele syndrome: Vertical transmission and expansion of the phenotype

Lateral meningoceles were first described by Lehman et al. [(1977); J Pediatr 90: 49–54] in a patient with other skeletal findings and distinctive craniofacial features. Subsequently, six more patients with the so‐called lateral meningocele syndrome (LMS) have been reported. We describe the findings in three new cases and expand the phenotype. The existence of an affected mother and daughter supports the hypothesis that LMS is a dominant disorder affecting primarily the connective tissue.

Magnetic resonance imaging in the prenatal diagnosis of congenital diarrhea

Congenital diarrhea is very rare, and postnatal diagnosis is often made once the condition has caused potentially lethal fluid loss and electrolyte disorders. Prenatal detection is important to improve the immediate neonatal prognosis. We aimed to describe the prenatal ultrasound and magnetic resonance (MRI) imaging findings in fetuses with congenital diarrhea.