Teresa Victoria

Current Imaging of Prenatally Diagnosed Congenital Lung Lesions

Congenital lung lesions refer to a spectrum of pulmonary developmental anomalies including, but not limited to, bronchial atresia, congenital pulmonary airway malformation (formerly known as congenital cystic adenomatoid malformation) and bronchopulmonary sequestration. These anomalies comprise about 90% of the anomalies seen in clinical practice. The advent of prenatal sonography and, more recently, fetal magnetic resonance imaging has changed our understanding and practice in the evaluation of congenital lung lesions. Postnatal imaging using low-dose computed tomography angiography (CTA) is extremely useful as it may provide information essential for differential diagnosis by allowing multiplanar reconstructions of the airway, lung parenchyma, and vasculature. The use of iodine in CTA permits the application of low-dose radiation protocols in these young patients. The purpose of this article is to emphasize the technical factors that may optimize low-dose CTA evaluation of these lesions. We also provide a description of prenatal imaging findings and helpful diagnostic clues that may be useful for the characterization of the most commonly encountered prenatally diagnosed pulmonary developmental anomalies.

Use of magnetic resonance imaging in prenatal prognosis of the fetus with isolated left congenital diaphragmatic hernia.

To investigate the prognostic value of magnetic resonance‐calculated fetal lung volumes (FLV) in fetuses with isolated left congenital diaphragmatic hernia (L‐CDH) who receive standardized prenatal and postnatal care at a single institution.

Fetal MRI-Calculated Total Lung Volumes in the Prediction of Short-Term Outcome in Giant Omphalocele: Preliminary Findings

Objective: To determine the value of fetal MRI-calculated total lung volumes (TLV) in the prediction of short-term outcome in patients with giant omphalocele (GO). Material and Methods: We reviewed all cases of GO undergoing fetal MRI after 21 weeks’ gestation and receiving postnatal care at our institution between 2003 and 2010. Observed/expected (O/E) TLV was calculated using age-matched TLV normograms [Radiology 2001;219:236–241]. Postnatal outcomes were stratified based on O/E TLV above or below 50% of expected. Results: Seventeen GO cases fulfilled the entry criteria. The mean age at fetal MRI evaluation was 25.8 ± 4.8 weeks’ gestation. The mean GO TLV (21.0 ± 13.2) was lower than age-matched population norms (p < 0.001), resulting in a mean O/E TLV of 52.3 ± 16.8%. The mean gestational age at delivery was 36.8 ± 1.6 weeks. Overall survival was 94%. Fourteen (88%) infants underwent staged reduction, and 2 underwent silver sulfadiazine treatment and delayed repair. Infants with ≤50% of predicted O/E TLV (n = 11, 65%) had lower Apgar scores at birth (p = 0.03), prolonged ventilatory support (p = 0.004), delayed oral intake (p = 0.03), and longer hospitalization (p = 0.03) compared to patients with ≥50% of expected O/E TLV. Two infants (both O/E TLV <50%) required tracheostomy placement. Conclusion: In the assessment of GO fetuses, MRI-based O/E TLV of <50% was predictive of increased postnatal morbidity.

Low-Dose Fetal CT in the Prenatal Evaluation of Skeletal Dysplasias and Other Severe Skeletal Abnormalities

OBJECTIVE Prenatal diagnosis of skeletal dysplasia is often difficult and based on findings with ultrasound, a technique with 40-60% sensitivity. The purpose of this study was to evaluate a preliminary experience in assessing severe prenatal osseous abnormalities with low-dose fetal CT. The hypothesis was that use of CT may improve the prenatal diagnosis of skeletal dysplasia beyond the available capabilities of ultrasound. MATERIALS AND METHODS Retrospective search of a radiology database (July 2008-February 2011) yielded the records of unenhanced CT examinations of patients referred because of abnormal fetal bones. The original ultrasound and CT reports as interpreted at image acquisition were independently analyzed by two radiologists blinded to the final diagnosis and to the findings of the opposing imaging modality. Blinded review of the images was also performed. Correlation was made with the postmortem and postnatal findings. RESULTS According to the reports of the studies, 5 of 21 cases were interpreted correctly with CT and incorrectly with ultrasound. In 17 cases, CT revealed additional osseous findings not in the ultrasound report. There were no cases in which ultrasound findings were correct and CT findings were incorrect. Blinded review of the images revealed that CT outperformed ultrasound (p < 0.001). There were a total of four CT errors among 218 total measures recorded and a total of 19 ultrasound errors among 218 total measures. CONCLUSION Although low-dose fetal CT should never be used as the initial diagnostic modality in cases of suspected skeletal dysplasia, it is a powerful imaging adjunct that depicts the fetal bones in exquisite detail. Use of CT of fetuses at risk of skeletal dysplasia may provide clinicians with more accurate information for counseling of families regarding neonatal morbidity and mortality.

Complex Genitourinary Abnormalities on Fetal MRI: Imaging Findings and Approach to Diagnosis

OBJECTIVE The objective of this article is to present the fetal MRI patterns of complex genitourinary abnormalities including epispadias-exstrophy complex, cloacal malformation, urogenital sinus anomaly, posterior urethral valves, and other causes that result in lower urinary tract dilatation without oligohydramnios. Relevant embryology will be reviewed, and practical points will be provided that can aid in interpretation. CONCLUSION Complex genitourinary abnormalities have recognizable imaging findings on fetal MRI. Imaging findings may be subtle; a high index of suspicion and a systematic checklist are useful for accurate diagnosis. Familiarity with fetal MRI patterns of complex genitourinary abnormalities is crucial for making more precise diagnoses that will likely impact pregnancy management, counseling, and postnatal treatment.

Contemporary pediatric gynecologic imaging.

Ultrasound is the primary screening modality for the evaluation of pediatric gynecologic maladies. Magnetic resonance imaging (MRI) is used progressively more in this field, particularly for the evaluation of complex pelvic masses and congenital anomalies. However, ultrasound remains the preferred modality due to the excellent visualization, the dynamic nature of the examination modality, lack of ionizing radiation and sedation risks, and comparatively lower cost. MRI is generally a second-line examination and is preferred over computed tomography as it does not involve the use of ionizing radiation. Additionally, visualization of the female reproductive system anatomy with MRI is superior to computed tomography, the latter being reserved generally for tumor staging. Fluoroscopic examinations and abdominal radiographs can provide additional information that may support a diagnosis.

Comparison Between 1.5-T and 3-T MRI for Fetal Imaging: Is There an Advantage to Imaging With a Higher Field Strength?

OBJECTIVE Fetal MRI at 3 T is emerging as a promising modality for evaluating fetal anatomy. The objective of this study was to compare the quality of images obtained with commonly used fetal imaging sequences at 1.5 T and 3 T. We hypothesized that the visualization and anatomic detail of fetal structures would be better at 3 T than at 1.5 T. MATERIALS AND METHODS A retrospective search of the radiology department database at our institution identified 58 fetal MRI examinations performed at 3 T to evaluate body abnormalities during the period from July 2012 to February 2014. A blind comparison was conducted between these examinations and 58 1.5-T MRI examinations of age-matched fetuses undergoing evaluation for similar abnormalities during the same period. The anatomic structures analyzed included the bowel, liver, kidney, airway, cartilage, and spine. Scores for the depiction of anatomic structures ranged from 0 to 4, with 4 denoting the best depiction. RESULTS Fetal imaging at 3 T was associated with higher imaging scores in the evaluation of the cartilage and spine when single-shot turbo spin-echo (SSTSE) and steady-state free precession (SSFP) sequences were used and in the assessment of most structures (e.g., bowel, liver, kidney, cartilage, and spine) when SSFP sequences were used. The mean scores for all structures evaluated with the use of SSTSE sequences were higher when MRI was performed at 3 T than at 1.5 T; similar findings were noted when SSFP sequences were used. Evaluation of imaging scores with regard to gestational age showed that scores improved with increasing gestational age on 1.5-T MRI but not on 3-T MRI. Overall, more imaging artifacts were found when imaging was performed at 3 T than at 1.5 T. CONCLUSION An overall advantage to performing fetal imaging at 3 T was made evident by the higher imaging scores obtained with 3-T MRI versus 1.5-T MRI when different fetal anatomic structures were evaluated. These higher scores were predominantly associated with use of SSFP sequences. The findings of this study and future advancements in MRI software and 3-T protocols may allow optimal visualization and examination of fetal pathologic abnormalities, thus better identifying fetal and maternal needs both prenatally and postnatally.

Use of ultrasound and MRI for evaluation of lung volumes in fetuses with isolated left congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is an anomaly that results in lung hypoplasia and pulmonary hypertension. The lungs of the CDH fetus have an abnormal architecture, with fewer bronchial branches and decreased number of arteries and veins, factors which result in pulmonary compromise postnatally. The goal of this review is to evaluate prenatal prognostic factors in the fetus with isolated left CDH, with particular emphasis on fetal MRI. These imaging indicators may be used to provide health professionals and the parents with the most accurate information about fetal prognosis.

Low-dose fetal CT for evaluation of severe congenital skeletal anomalies: preliminary experience

Congenital skeletal abnormalities compose a heterogeneous and complex group of conditions that affect bone growth and development and result in various anomalies in shape and size of the skeleton. Prenatal sonographic diagnosis of these anomalies is challenging because of the relative rarity of each skeletal dysplasia, the multitude of differential diagnoses encountered when the bony abnormalities are identified, lack of precise molecular diagnosis and the fact that many of these disorders have overlapping features and marked phenotypic variability. The following review is a preliminary summary of our experience at the Children’s Hospital of Philadelphia (CHOP) using low-dose fetal CT in the evaluation of severe fetal osseous abnormalities.

Fetal MRI of clubfoot associated with myelomeningocele

BackgroundThe sensitivity and specificity of evaluating clubfoot deformity by MR in high-risk fetuses is currently unknown.ObjectiveTo correlate fetal MRI with US in the assessment of clubfoot and to identify the MRI features most characteristic of clubfoot.Materials and methodsWith IRB approval and informed consent, the presence of fetal clubfoot was prospectively evaluated in mothers referred for MRI for a fetus with myelomeningocele. Two radiologists blind to the US results independently reviewed the MRI for the presence of clubfoot. MRI results were compared with US results obtained the same day and birth outcomes.ResultsOf 20 patients enrolled, there were 13 clubfeet. Interobserver agreement for the presence of clubfoot was 100%. The sensitivity of the MRI exam was 100% and the specificity 85.2%. A dedicated sagittal imaging plane through the ankle region allowed the most confident diagnosis; medial deviation of the foot relative to the leg was seen in all 13 fetuses with clubfoot.ConclusionThe correlation of fetal MRI with US in the evaluation of clubfoot yields a sensitivity of 100% and specificity of 85.2%. The sagittal plane provided the most useful information.