Understanding Lymphatic Anatomy and Abnormalities at Imaging.

Lymphatic abnormalities encompass a wide range of disorders spanning solitary common cystic lymphatic malformations (LMs) to entities involving multiple organ systems such as lymphangioleiomyomatosis. Many of these disorders are rare, yet some, such as secondary lymphedema from the treatment of malignancy (radiation therapy and/or lymph node dissection), affect millions of patients worldwide. Owing to complex and variable anatomy, the lymphatics are not as well understood as other organ systems. Further complicating this is the variability in the description of lymphatic disease processes and their nomenclature in the medical literature. In recent years, medical imaging has begun to facilitate a deeper understanding of the physiology and pathologic processes that involve the lymphatic system. Radiology is playing an important and growing role in the diagnosis and treatment of many lymphatic conditions. The authors describe both normal and common variant lymphatic anatomy. Various imaging modalities including nuclear medicine lymphoscintigraphy, conventional lymphangiography, and MR lymphangiography used in the diagnosis and treatment of lymphatic disorders are highlighted. The authors discuss imaging many of the common and uncommon lymphatic disorders, including primary LMs described by the International Society for the Study of Vascular Anomalies 2018 classification system (microcystic, mixed, and macrocystic LMs; primary lymphedema). Secondary central lymphatic disorders are also detailed, including secondary lymphedema and chylous leaks, as well as lymphatic disorders not otherwise easily classified. The authors aim to provide the reader with an overview of the anatomy, pathology, imaging findings, and treatment of a wide variety of lymphatic conditions. ©RSNA, 2022.

Prenatal assessment of congenital diaphragmatic hernia at north american fetal therapy network centers: A continued plea for standardization.

INTRODUCTION: Prenatal work-up for congenital diaphragmatic hernia (CDH) is important for risk stratification, standardization, counseling, and optimal therapeutic choice. To determine current practice patterns regarding prenatal CDH work-up, including prenatal ultrasound and magnetic resonance imaging (MRI) use, and to identify areas for standardization of such evaluation between fetal centers. METHODS: A survey regarding prenatal CDH work-up was sent to each member center of the North American Fetal Therapy Network (NAFTNet) (n = 36). RESULTS: All responded. Sonographic measurement of lung-to-head ratio (LHR) was determined by all, 89% (32/36) of which routinely calculate observed-to-expected LHR. The method for measuring LHR varied: 58% (21/36) used a "trace" method, 25% (9/36) used "longest axis," and 17% (6/36) used an "antero-posterior" method. Fetal MRI was routinely used in 78% (28/36) of centers, but there was significant variability in fetal lung volume measurement. Whereas all generated a total fetal lung volume, the planes, methodology and references values varied significantly. All evaluated liver position, 71% (20/28) evaluated stomach position and 54% (15/28) quantified the degree of liver herniation. More consistency in workup was seen between centers offering fetal intervention. CONCLUSION: Prenatal CDH work-up and management differs considerably among North American fetal diagnostic centers, highlighting a need for its standardization.

Imaged-guided and muscle sparing laparoscopic anorectoplasty using real-time magnetic resonance imaging.

A challenge when repairing imperforate anus is positioning the neo-rectum into the center of the sphincter muscle complex (SMC) with limited muscle injury and scarring. Unfortunately, the path through the components of the SMC are often non-linear. We have used MRI to delineate the complex and guide the needle through the center using standard MRI-guidance (Raschbaum GR et al. J Pediatr Surg 45:220-223, 2010; Thomas TT et al. J Pediatr Surg 35:927-930, 2000). However, asynchronous scanning requires multiple, time-consuming scans to advance the needle in stepwise fashion. Asynchronous scanning also prevents visualizing the needle as it is advanced. We recently integrated software into the MRI operative suite that allows placement of the needle with real-time MRI. We report the feasibility and utility of real-time MRI-assisted laparoscopic assisted anorectoplasty (RT MRI-LAARP). Needle guidance was performed with Siemens Espree 1.5 T MRI with T1 Flash RT Sequence. After needle placement, laparoscopic mobilization, fistula takedown and pull-through was performed using the needle to guide dilation to create a tract to pull-through the neo-rectum. Charts of patients who underwent RT MRI-LAARP were reviewed. Demographics, anatomy, number of needle passes, OR duration and complications are reported. There were five children that underwent RT MRI-LAARP; one was a redo secondary to a retracted rectovestibular fistula. Operative time ranged from 187-505 min. Average hospital stay was 4.0 ± 1.0 days. There were no intraoperative complications although one patient had temporary urinary retention post-op. Muscle sparring laparoscopic anorectoplasty using real-time MRI is feasible and facilitates needle placement through the SMC.

Calculating Observed-to-Expected Total Fetal Lung Volume in CDH Fetuses in Twin Gestation: Is There a Better Way?

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a potentially lethal birth defect, and identifying prenatal predictors of outcome is important. Observed-to-expected total fetal lung volume (o/e TFLV) has been shown to be a predictor of severity and useful in risk stratification but is variable due to different TFLV formulas. OBJECTIVES: To calculate o/e TFLV for CDH patients part of a twin gestation using the unaffected sibling as an internal control and comparing these values to those calculated using published formulas for TFLV. METHODS: Seven twin gestations with one fetus affected by CDH were identified between 2006 and 2017. The lung volume for each twin was calculated using magnetic resonance imaging (MRI), and o/e TFLV was calculated using the unaffected twin's TFLV. This percentage was then compared to the o/e TFLV calculated using published formulas. RESULTS: Lung volumes in the unaffected twins were within normal ranges at the lower end of the spectrum. No single TFLV formula was found to correlate perfectly. Intraclass correlation coefficient estimate was most consistent for o/e TFLV calculated with the Meyers formula and supported by Bland-Altman plots. CONCLUSIONS: O/e TFLV measured in CDH/non-CDH twin gestations using the unaffected sibling demonstrated agreement with o/e TFLV calculated using the Meyers formula. We urge the fetal community to standardize the method, use, and interpretation of fetal MRI in the prenatal evaluation of CDH.

Early Delivery of Sacrococcygeal Teratoma with Intraspinal Extension.

Sacrococcygeal teratoma (SCT) with intraspinal extension is rare. There is a risk of paraplegia associated with prolonged spinal cord compression. We present the case of an infant with a prenatal diagnosis of an SCT with a large intraspinal component that was causing compression of the lower spinal cord. Ultrasound at 33 weeks showed bilateral lower extremity and foot movement without hydrops or cardiac failure. Multidisciplinary decision was made to administer betamethasone and proceed with Cesarean delivery at 34 weeks. A vigorous live-born female was delivered and a multilevel laminectomy was performed at day of life 4. The pelvic resection was performed at 4 months. Pathology revealed mature teratoma. She had an uncomplicated postoperative course, is ambulatory, continent of stool, and has no evidence of recurrence. We conclude that intraspinal extension of SCT should be evaluated prenatally with ultrasound and fetal MRI. If there is concern for spinal cord compression, early delivery and urgent decompressive laminectomy may diminish the neurologic sequelae of prolonged spinal cord compression. Since these cases are rare, risks of prematurity need to be weighed against the neurologic risks. These infants should be treated with a multidisciplinary approach.

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.

Functional Outcomes of Patients Who Underwent Anorectal Malformation Repair Using MRI Guidance.

BACKGROUND: Despite the initiation of minimally invasive laparoscopic techniques, the majority of patients who undergo anorectal malformation repair still experience functional bowel issues in childhood, including constipation and fecal incontinence. In this study, we evaluate the functional outcomes of a procedure in which magnetic resonance imaging guidance is used during initial laparoscopic repair to better locate the epicenter of the sphincter muscle complex and pelvic floor with the goal of more accurate placement of the neoanus and improved functional outcomes. METHODS: A retrospective chart review evaluated demographic, operative, and outcome details for patients who underwent this procedure. A telephone survey was employed to determine levels of social continence using the validated Baylor Continence Scale and to determine what type of bowel management is used. RESULTS: Twenty-six patients were included. Median age at operation was 7 months, and median age at follow-up was 4 years old, with a range of 1-9. Bowel management regimen results revealed that 19 % (n = 5) use no bowel management regimen, 58 % (n = 15) use laxatives only, and 23 % (n = 6) use enemas. Enema use was not associated with different spine or sacral anomalies (p = 0.77). Fifteen patients (58 %) answered the Baylor Continence Scale questions and had a median score of 14. No difference was found in scores when accounting for lesion level (p = 0.43), quality of needle placement (p = 0.46), or quality of sphincter muscles (p = 0.75). CONCLUSIONS: Using MRI guidance in the repair of anorectal malformations shows promise in both the qualitative and quantitative functional outcomes of this complex patient population. LEVEL OF EVIDENCE: Level III.

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.

Diffuse uterine leiomyomatosis in a child.

Leiomyomas are the most common benign uterine tumor; however, this entity is relatively uncommon in the pediatric population. Although leiomyomas most commonly present as solitary uterine masses, unusual patterns of growth have been described including diffuse leiomyomatosis. In this condition, the myometrium of the uterus is symmetrically expanded by innumerable confluent leiomyomas; this pattern of growth is quite uncommon and has never been reported in a pediatric patient. This case report illustrates the imaging appearance of diffuse uterine leiomyomatosis in an otherwise healthy 16-year-old girl.

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.

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.

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.

Case Report: A Relatively Mild Presentation of Unilateral Congenital Pulmonary Lymphangiectasia.

Pulmonary lymphangiectasia (PL) is a rare congenital disorder of pulmonary lymphatic development. Although it was traditionally a fatal disorder of infancy, some cases in later childhood have been reported, suggesting a spectrum of severity. We present an unusual case of unilateral, congenital pulmonary lymphangiectasia. Our patient presented with neonatal respiratory distress, a chronic wet cough and recurrent episodes of bronchitis. Chest CT revealed thickening of the interlobular septae of the right lung. A lung biopsy confirmed the diagnosis of lymphangiectasia. His clinical course is characterized by chronic coughing and recurrent bronchitis but normal growth and development. This case illustrates a relatively mild presentation of unilateral PL, which, along with other reports, suggests variability in the presentation and severity of this disorder. In the absence of imaging and histological examination, mild presentations may go undiagnosed.

Ultrasound-guided pediatric inguinal hernia repair.

PURPOSE: Inguinal hernias are amongst the most common surgical conditions in children. Typically, these repairs are performed through an open or laparoscopic approach, using a high ligation of the hernia sac. The use of ultrasound has been described in identifying and evaluating hernia contents in children. Our goal was to determine if ultrasound guidance could be used to perform a high ligation of the hernia sac in pediatric patients. METHODS: Following IRB approval, a retrospective review of all female patients at a single center undergoing ultrasound guided inguinal hernia repair between 2017 and 2018 was performed. Pre-operative characteristics, intra-operative outcomes, and post-operative outcomes were all evaluated. Laparoscopy was used to evaluate the repair and evaluate for a contralateral hernia. Male patients did not undergo ultrasound inguinal hernia repair to avoid damage to the vas deferens and vessels. RESULTS: A total of 10 patients with 13 hernias total were found during the study period. A total of one patient was converted to a laparoscopic repair. No patients were found to have an inappropriate repair or a missed contralateral hernia, and there were no vascular injuries or injuries to surrounding structures. No patients had a hernia recurrence during the study period. CONCLUSION: This study demonstrates the safety and feasibility of ultrasound guided inguinal hernia repairs in female pediatric patients. Further study is needed to compare these repairs to existing techniques, evaluate for recurrences over time, and evaluate if these repairs can be performed without general anesthetic in some patients.

Conjoined twins: an obstetrician's guide to prenatal care and delivery management.

OBJECTIVE: Obstetricians infrequently encounter conjoined twins. Much of the clinical care literature focuses on postnatal management from a neonatology and pediatric surgery perspective; guidance on obstetrical management is limited. We outline steps for prenatal evaluation, obstetrical care, and delivery planning. STUDY DESIGN: Experiences with two cases of conjoined twins. RESULTS: We identified several points throughout the planning, delivery, and postnatal process that are important to highlight for optimizing clinical outcome, patient safety, and parental satisfaction. CONCLUSION: After diagnosis, patients should be referred to a center experienced in the management of conjoined twins. Specialists in fields including maternal fetal medicine, pediatric surgery, neonatology, and radiology play a vital role in the management of these patients. Early referral allows for timely family counseling and decision-making. Prenatal evaluation beyond the first trimester should include a detailed ultrasound, fetal echocardiogram, and fetal MRI. 3D printed life-sized models can improve delivery planning and patient understanding.

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.

Discordant prenatal ultrasound and fetal MRI in CDH: wherein lies the truth?

PURPOSE: Prenatal risk assessment of congenital diaphragmatic hernia (CDH) relies on prenatal ultrasound (U/S) and fetal magnetic resonance imaging (MRI). When the modalities differ in prognosis, it is unclear which is more reliable. METHODS: Retrospective chart review identified cases of prenatally diagnosed CDH from 4/2010-6/2018 meeting inclusion criteria. Demographic, radiologic, and postnatal outcomes data were collected. Ultrasound- versus MRI-based prognosis (mild, moderate, and severe) was compared with clinical outcomes. Kappa measures compared congruency in disease severity scaling between imaging modalities, while logistic regression and receiver operating characteristics curves compared the ability of each modality to predict outcomes. RESULTS: Forty-two patients met criteria. Both U/S- and MRI-based prognosis categories differentiated for survival. MRI categories differentiated for ECMO use, surgical repair, and defect type. O/e TFLV better discriminated for survivors and defect type than o/e LHR. Seventeen (40.5%) had discordant prenatal prognostic categories. In 13/17 (76.5%), o/e TFLV predicted higher severity when compared to o/e LHR, but sample size was insufficient to compare accuracy in cases of discordance. CONCLUSIONS: Clinical outcomes suggest fetal MRI may more accurately predict severe pulmonary hypoplasia compared to prenatal ultrasound. Our analysis suggests fetal MRI is a valuable adjunct in the prenatal evaluation of CDH. LEVEL OF EVIDENCE: Level III. TYPE OF STUDY: Retrospective Review.

Diagnostic accuracy of imaging studies in congenital lung malformations.

BACKGROUND: Although fetal ultrasound, fetal MRI and postnatal CT are now widely used in the evaluation of congenital lung malformations (CLM), their diagnostic accuracy remains undefined. OBJECTIVE: To correlate prenatal and postnatal imaging studies with pathological data after CLM resection. DESIGN: Retrospective, descriptive case series study. SETTING: A North American tertiary care centre. PATIENTS: One hundred and three consecutive lung resections for a suspected CLM between 1 January 2005 and 31 December 2015. MAIN OUTCOME MEASURES: Diagnostic accuracy of imaging diagnosis compared with pathological evaluation. RESULTS: Pathological diagnoses included congenital pulmonary airway malformation ((CPAM) n=45, 44%), bronchopulmonary sequestration (BPS; n=25, 24%), CPAM/BPS hybrid lesions (n=22, 21%) and pleuropulmonary blastoma (n=2, 2%). Fetal ultrasound detected 85 (82.5%) lesions and correctly diagnosed whether or not a lesion was a CPAM in 75% of cases (sensitivity 93%, specificity 32%). Fetal MRI had a similar concordance rate (73%) but was superior in correctly determining whether a systemic feeding vessel was present in 80% of cases (sensitivity 71%, specificity 88%) compared with an ultrasound accuracy rate of 72% (sensitivity 49%, specificity 93%). By comparison, postnatal CT correctly diagnosed whether a CPAM was present in 84% of cases (sensitivity 86%, specificity 77%) and whether a systemic feeding vessel was present in 90% of cases (sensitivity 92%, specificity 88%). CONCLUSIONS: Fetal ultrasound remains an important tool in the detection and evaluation of congenital lung malformations. However, it does not correctly predict histology in approximately 25% of prenatally detected CLMs and remains limited by relatively poor sensitivity for systemic feeding vessels pathognomic for a bronchopulmonary sequestration. These data suggest the importance of obtaining additional cross-sectional imaging, preferably a postnatal CT scan, in all patients to help counsel families and to guide in the optimal management of these lesions.