Prenatal diagnosis of intestinal nonrotation using magnetic resonance imaging: Is it possible?

BACKGROUND: Malrotation of the bowel refers to any variation in the rotation and fixation of the gastrointestinal tract during the first trimester and is most commonly detected postnatally. Nonrotation of the bowel and incomplete rotation of the bowel are subtypes of malrotation. OBJECTIVE: To determine if the nonrotation subtype of malrotation of the bowel can be detected on prenatal magnetic resonance imaging (MRI). MATERIALS AND METHODS: Cases from 2012 to 2018 with nonrotation of the bowel without obstruction confirmed by imaging, surgery and/or autopsy were compared to prenatal imaging. Prenatal imaging was retrospectively reviewed to determine if prenatal diagnosis of malrotation could be made. Exclusion criteria included diaphragmatic hernia, omphalocele and gastroschisis. RESULTS: Ten cases of nonrotation diagnosed postnatally by upper gastrointestinal series (upper GI)/small bowel follow-through (SBFT) or autopsy had prenatal MRI. Prenatal MR studies were performed for assessment of heterotaxy syndrome with congenital heart disease (6/10), congenital heart disease with additional anomalies (suspected VACTERL [vertebral, anorectal, cardiac, tracheoesophageal, renal, limb] and suspected lung agenesis, ventriculomegaly) (3/10) and skeletal dysplasia (1/10). Eight upper GI/SBFT cases demonstrated nonrotation of the bowel without obstruction with the small bowel completely on one side of the abdomen contralateral to the stomach and the colon ipsilateral to the stomach; four cases were confirmed by surgery. The small bowel in one upper GI/SBFT case was unilateral contralateral to the stomach with a meandering colon. One case had nonrotation diagnosed at autopsy. There were no cases of postnatal midgut volvulus. Retrospective review of the 10 cases had prenatal MRI performed between 23 and 37 weeks of gestation. The coronal plane was the most optimal plane to assess the position of the stomach, small bowel and colon in relationship to each other. The small bowel was best assessed on T2-weighted images while the colon was best assessed on T1-weighted images. A nonrotated position of the small bowel was present in all 10 fetal MRI cases mirroring postnatal findings, with the small bowel contralateral to the stomach in 9/10 cases and ipsilateral to the stomach (in the right abdomen) in 1/10 cases. The colon was visualized by prenatal MRI in 9/10 cases, with 1 case limited due to a lack of T1-weighted imaging. A nonrotated position of the colon contralateral to the small bowel was present in 7/9 cases. In 2/9 cases, the colon was wandering, positioned on both sides of the midline. Colonic position in all nine cases matched postnatal findings. No cases presented with prenatal bowel obstruction. CONCLUSION: Detection of nonrotation of the bowel is possible on prenatal MRI.

Normal size of the fetal adrenal gland on prenatal magnetic resonance imaging.

BACKGROUND: The adrenal gland plays a vital role in fetal growth. Many disease states such as congenital adrenal hyperplasia, hemorrhage and tumors can lead to morphological changes in the gland. Ultrasound measurements of normal adrenal sizes in the fetus reported in the literature have shown a trend of increasing size with gestational age. There is no literature available on standard fetal adrenal sizes or detailed appearance by fetal MRI. OBJECTIVE: The purpose of this study was to provide MR data on the size and signal characteristics of the fetal adrenal gland throughout the second and third trimesters. MATERIALS AND METHODS: In this retrospective review, we selected 185 prenatal MRIs obtained from Jan. 1, 2014, to May 31, 2017, with normal abdominal findings for inclusion. The adrenal glands were identified in coronal, sagittal or axial T2-W planes and coronal T1-W plane when available. We measured the length and thickness of the medial and lateral limbs of the right and left adrenal glands and recorded signal intensity on T1-W and T2-W sequences, gender and gestational age in each case. RESULTS: The gestational age (GA) ranged 18-37 weeks. Visibility of the adrenal glands on T2-W images was high (90.3-97.2%) up to 30 weeks of GA but declined afterward (47.5-62.2% at 31-37 weeks). Visibility on T1-W images increased with GA, ranging from 21.4% visibility at 18-22 weeks and increasing to 40% at 35-37 weeks. Mean lengths of the adrenal gland limbs steadily increased from 8.2 mm at 18-22 weeks to 11.0 mm at 35-37 weeks. In the second trimester, adrenal glands were low in signal intensity on T2-W images and were surrounded by hyperintense perirenal fatty tissue. In the third trimester, the glands became less distinct, with increasing signal and obliteration of perirenal tissue. The glands were moderately hyperintense on T1-W images throughout pregnancy, with increasing visibility as pregnancy progressed. CONCLUSION: Normal sizes and signal intensities for adrenal glands are reported. Visibility of adrenal glands on T2-W images was 90.3-97.2% up to 30 weeks but declined thereafter. Visibility on T1-W images increased in the third trimester. Adrenal gland sizes increased with gestational age.

Coordination of the Fetal Medicine Institute and the Cleft and Craniofacial Center: Application to Early Management of Infants With Cleft Lip and Palate.

BACKGROUND/PURPOSE: The primary objective of this study is to describe the authors' experience at the Children's National Health System with the coordination of the Fetal Medicine Institute and the Cleft and Craniofacial Center. This collaboration highlights the accuracy and completeness of prenatal diagnosis of cleft abnormalities with expedient postnatal management. METHODS: With Institutional Review Board approval, the authors retrospectively reviewed 74 patients referred for potential orofacial cleft and 44 met the inclusion criteria. Follow-up fetal ultrasonography is typically performed and three-dimensional imaging was performed when feasible. If questionable anomalies or facial findings are present on these studies, the authors proceed with fetal magnetic resonance imaging. A thorough consultation is held with the cleft team, resulting in a comprehensive plan of care. Postnatal examination confirmed the correct prenatal diagnosis in nearly all patients. RESULTS: Sensitivity and specificity for isolated unilateral cleft lip were 89% and 100%, respectively; for unilateral cleft lip and palate, sensitivity and specificity were 82% and 90%, respectively; for bilateral cleft lip and palate, sensitivity and specificity were 97% and 90%, respectively. Initial postnatal evaluation by the cleft surgeon occurred at an average age of 21 days after birth. All patients who were candidates for presurgical orthodontia were treated at an appropriate young age (mean: 66.5 days). CONCLUSIONS: Coordinated prenatal evaluation of patients with cleft lip/palate by multidisciplinary centers plays an important role in the care of these complex patients. The results of the authors' study demonstrated high sensitivity and specificity for the prenatal diagnosis of cleft lip/palate, leading to timely postnatal evaluation and treatment.

Testicular torsion with preserved flow: key sonographic features and value-added approach to diagnosis.

Testicular sonography has contributed greatly to the preoperative diagnosis of testicular torsion in the pediatric patient and is the mainstay for evaluation of acute scrotal pain. Despite its high sensitivity and specificity, both false-negative and false-positive findings occur. Presence of documented Doppler flow within the testis might be a dissuading factor for surgical exploration with resultant testicular loss in the false-negative cases. Our goal is to illustrate key sonographic features in the spectrum of testicular torsion with preserved testicular flow, and to describe how to differentiate testicular torsion from epididymitis in order to avoid the under-diagnosis of testicular torsion. We simplify the anatomy of the bell clapper testis. We also describe our sonographic protocol for testicular torsion and share valuable tips from our approach to challenging cases.

Severe nasomaxillary hypoplasia (Binder phenotype) on prenatal US/MRI: an important marker for the prenatal diagnosis of chondrodysplasia punctata.

BACKGROUND: Chondrodysplasia punctata is a skeletal dysplasia caused by a diverse spectrum of etiologies, with outcomes ranging from antenatal demise to a normal life span. Prenatal detection can be challenging. OBJECTIVE: To review a series of cases of chondrodysplasia punctata associated with nasomaxillary hypoplasia, known as the Binder phenotype, and to highlight prenatal ultrasound and MRI findings, as well as postnatal MRI and radiographic findings. MATERIALS AND METHODS: We retrospectively reviewed ultrasound, MRI and radiographic imaging findings in postnatally confirmed cases of chondrodysplasia punctata from 2001 to 2017. We analyzed prenatal findings and correlated them with maternal history, postnatal imaging, phenotype, genetics and outcome. RESULTS: We identified eight cases, all with prenatal US and six of eight with prenatal MRI between 18 weeks and 32 weeks of gestational age. Reasons for referral included midface hypoplasia in four cases; family history in one case; intrauterine growth restriction in one case; short long-bones, intrauterine growth restriction and multicystic kidney in one case; and multiple anomalies in one case. In six cases, postnatal radiographs were performed. In four cases, postnatal spine MRI imaging was performed. The diagnosis of chondrodysplasia punctata was suggested in prenatal reports in six of eight fetuses. Seven of eight fetuses had Binder phenotype with severe nasomaxillary hypoplasia. Limb length was mildly symmetrically short in four of eight cases and normal in four of eight fetuses. Two of eight fetuses had epiphyseal stippling identified prenatally by US; this was present postnatally in six neonates on radiographs. Hand and foot abnormalities of brachytelephalangy were not detected on the prenatal US or MRI but were present in six of eigth fetuses on postnatal radiographs or physical exam. Four of eight fetuses had prenatal spine irregularity on US from subtle stippling. Six of eight had spine stippling on postnatal radiographs. One fetus had cervicothoracic kyphosis on prenatal US and MRI, and this was postnatally present in one additional neonate. One case had prenatally suspected C1 spinal stenosis with possible cord compression, and this was confirmed postnatally by MRI. There was a maternal history of systemic lupus erythematosus in two and hyperemesis gravidarum in one. Outcomes included one termination and seven survivors. CONCLUSION: Chondrodysplasia punctata can be identified prenatally but findings are often subtle. The diagnosis should be considered when a fetus presents with a hypoplastic midface known as the Binder phenotype. Maternal history of lupus, or other autoimmune diseases or hyperemesis gravidarum can help support the diagnosis.

Prenatal congenital vertical talus (rocker bottom foot): a marker for multisystem anomalies.

BACKGROUND: Congenital vertical talus is a rare foot anomaly characterized by a prominent calcaneus and rigid forefoot dorsiflexion. While congenital vertical talus has been associated with anomalies such as trisomy 18, myelomeningocele and arthrogryposis, postnatal series have reported cases of isolated congenital vertical talus. OBJECTIVE: The purpose of our study was to determine the incidence of isolated congenital vertical talus prenatally and identify the most common anomalies associated with this finding. MATERIALS AND METHODS: A retrospective review was performed of congenital vertical talus cases identified in our fetal center from 2006 to 2015. The prenatal US and MR imaging appearance of congenital vertical talus was evaluated and differentiation from congenital talipes equinovarus was assessed. Studies were evaluated for additional abnormalities affecting the central nervous system, face, limbs, viscera, growth and amniotic fluid. Imaging findings were recorded and correlated with outcomes when available. RESULTS: Twenty-four cases of congenital vertical talus were identified prenatally (gestational age: 19-36 weeks). All 24 had prenatal US and 21 also underwent fetal MRI on the same day. There were no isolated cases of congenital vertical talus in this series; all 24 had additional anomalies identified prenatally. Sixteen cases had bilateral congenital vertical talus (67%). Additional anomalies were identified in the brain (15), spine (11), face (6), abdominal wall (3), heart (8) and other limbs (12). Chromosomal abnormalities were identified in 6 of 20 patients who underwent genetic testing. Overall, US held some advantage in detecting the abnormality: in 10 cases, US depicted congenital vertical talus more clearly than MRI; in 8 cases, US and MRI were equal in detection and in 3 cases, MRI was superior. In 9/15 cases with intracranial abnormalities, MRI was superior to US in demonstrating structural anomalies. Outcomes included termination (11), intrauterine fetal demise (1), stillbirth or immediate neonatal demise (5), lost to follow-up (1), and 6 survivors with postnatal follow-up. CONCLUSION: In our series, there were no cases of isolated congenital vertical talus, with additional anomalies variably affecting multiple systems including the brain, spine, face, viscera and limbs. When congenital vertical talus is identified prenatally, a thorough search for additional anomalies is indicated. Fetal MRI can be a useful adjunct in confirming the diagnosis and further delineating additional anomalies, particularly in the brain and spine.

Prenatal magnetic resonance and ultrasonographic findings in small-bowel obstruction: imaging clues and postnatal outcomes.

BACKGROUND: Prenatal small-bowel obstruction can result from single or multiple atresias, and it can be an isolated abnormality or part of a syndrome. It is sometimes the first manifestation of cystic fibrosis. Accurate prediction of the level of obstruction and length of bowel affected can be difficult, presenting a challenge for counseling families and planning perinatal management. OBJECTIVE: To review the prenatal US and MRI findings of small-bowel obstruction and to assess whether fetal MRI adds information that could improve prenatal counseling and perinatal management. MATERIALS AND METHODS: We retrospectively reviewed 12 prenatally diagnosed cases of small-bowel obstruction evaluated by both US and MRI from 2005 to 2015. We analyzed gestational age at evaluation, US and MRI findings, gestational age at delivery and postnatal outcomes. RESULTS: The final diagnoses were jejunal atresia (7), ileal atresia (1), cystic fibrosis (3) and combined jejunal and anal atresia (1). Four of the eight with jejunal atresia were found to have multiple small-bowel atresias. Prenatal perforation was noted in three. We identified a trend of increasing complexity of bowel contents corresponding to progressively distal level of obstruction, as indicated by increasing US echogenicity and high T1 signal on MRI. Seven cases of jejunal atresia and one case of ileal atresia demonstrated small ascending, transverse and descending colon (microcolon) with filling of a normal-diameter rectum. In contrast, all three fetuses with cystic fibrosis and the fetus with jejunal-anal atresia demonstrated microcolon as well as abnormal paucity or absence of rectal meconium. Polyhydramnios was present in nine. Eight were delivered prematurely, of whom seven had polyhydramnios. The fetus with jejunal and anal atresia died in utero. Postnatally, three had short gut syndrome, all resulting from multiple jejunal atresias; these three were among a subset of four fetuses whose bowel diameter measured more than 3 cm. Eight infants had no further gastrointestinal complications. The presence of multiple atresias was not predicted by prenatal US or MRI. CONCLUSION: MR provides useful additional information regarding meconium distribution in the small bowel, which helps to clarify the level of obstruction. MR was additionally useful in the assessment of colon and rectal contents, serving as a fetal enema. Abnormally diminished meconium in the rectum suggests cystic fibrosis or combined small-bowel and colonic obstruction, information that is useful in counseling and preparing for postnatal care.

Ultrasound and MR imaging findings in prenatal diagnosis of craniosynostosis syndromes.

BACKGROUND: Craniosynostosis syndromes are uncommonly encountered in the prenatal period. Identification is challenging but important for family counseling and perinatal management. OBJECTIVE: This series examines prenatal findings in craniosynostosis syndromes, comparing the complementary roles of US and MRI and emphasizing clues easily missed in the second trimester. MATERIALS AND METHODS: Six prenatal cases evaluated from 2002 through 2011 were retrospectively reviewed. Referral history, gestational age, and sonographic and MRI findings were reviewed by three pediatric radiologists. Abnormalities of the calvarium, hands, feet, face, airway and central nervous system were compared between modalities. RESULTS: The diagnosis was Apert syndrome in three, Pfeiffer syndrome in two and Carpenter syndrome in one. The gestational age at evaluation ranged from 21 to 33 weeks. All six were evaluated by MRI and US, with two undergoing repeat evaluation in the third trimester, yielding a total of eight MRIs and US exams. The referral history suggested cloverleaf skull in two cases but did not suggest craniosynostosis syndrome in any case. In four, the referral suggested central nervous system (CNS) findings that were not confirmed by MRI; additional CNS findings were discovered in the remaining two. In four cases, developing turricephaly resulted in a characteristic "lampshade" contour of the fetal head. Hypertelorism and proptosis were present in five, with proptosis better appreciated by MRI. Digit abnormalities were present in all, seen equally well by MRI and US. Lung abnormalities in the second trimester in one fetus resolved by the third trimester. CONCLUSION: Prenatal diagnosis of craniosynostosis syndromes is difficult prior to the third trimester. MRI and US have complementary roles in evaluation of these patients.

Alveolar Cleft Size on Prenatal Two-Dimensional Ultrasonography Predicts Cleft of the Secondary Palate in Unilateral Cleft Lip.

SUMMARY: Prenatal diagnosis of cleft palate (CP) is challenging. The current study's objective was to investigate whether prenatal alveolar cleft width is associated with the likelihood of a cleft of the secondary palate in unilateral cleft lip (CL). The authors reviewed two-dimensional ultrasound (US) images in fetuses with unilateral CL from January of 2012 to February of 2016. Images of the fetal face were obtained with a linear and/or curved probe in the axial and coronal planes. Measurements of the alveolar ridge gap were taken by the senior radiologist. Postnatal phenotype findings were compared with prenatal findings. Thirty patients with unilateral CL met inclusion criteria; average gestational age was 26.67 ± 5.11 weeks (range, 20.71 to 36.57 weeks). Ten fetuses were found to have an intact alveolar ridge by prenatal US; postnatal examination confirmed intact secondary palate in all. Small alveolar defects (<4 mm) were noted in three fetuses; postnatal examination documented CP in a single patient. CP was confirmed in 15 of the remaining 17 fetuses who had alveolar cleft width greater than 4 mm. An alveolar defect of greater than or equal to 4 mm on prenatal US was associated with greater likelihood of a cleft of the secondary palate [c 2 (2, n = 30) = 20.23; P < 0.001]. In the setting of unilateral CL, prenatal US documentation of alveolar defects greater than or equal to 4 mm are highly predictive of the presence of a cleft of the secondary palate. Conversely, an intact alveolar ridge is associated with an intact secondary palate. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.

Neuroimaging Findings in Normocephalic Newborns With Intrauterine Zika Virus Exposure.

BACKGROUND: Congenital Zika infection can result in a spectrum of neurological abnormalities in the newborn. Newborns exposed to Zika virus in utero often have neuroimaging as part of their clinical evaluation. METHODS: Through the Congenital Zika Program at Children's National Health System in Washington DC, we performed fetal or neonatal neuroimaging, including magnetic resonance imaging and ultrasound, on over 70 fetuses or neonates with intrauterine Zika exposure. Novel findings on neonatal brain magnetic resonance imaging were observed in two instances. RESULTS: Gadolinium-contrast magnetic resonance imaging showed enhancement of multiple cranial nerves at three days of age on one infant. Another infant underwent magnetic resonance imaging at 16 days of age and was shown to have a chronic ischemic cerebral infarction. This infant had previously normal fetal magnetic resonance imaging. CONCLUSION: Cranial nerve enhancement and cerebral infarction may be among the expanding list of neurological findings in congenital Zika infection. Postnatal brain magnetic resonance imaging should be considered for newborns exposed to Zika virus in utero.

Achondroplasia in the Premature Infant: An Elusive Diagnosis in the Neonatal Intensive Care Unit.

Achondroplasia is a difficult prenatal diagnosis to make before the late second and third trimester. We describe two cases where an infant was born prematurely with no overt signs of achondroplasia. Despite multiple chest and abdominal radiographs during the neonatal course, the diagnosis was not made until term equivalent age was reached. We retrospectively reviewed these two cases to highlight the elusive findings of achondroplasia in the premature infant.

Fetal anemia, cerebellar hemorrhage and hypoplasia associated with congenital Parvovirus infection.

We report a case of fetal cerebellar hemorrhage and hypoplasia, identified by fetal MRI after intrauterine blood transfusion at 21 weeks' gestation for treatment of severe anemia due to congenital Parvovirus infection. Postnatal MRI confirmed atrophy of bilateral cerebellar hemispheres and inferior vermis. Cerebellar capillaries may be extremely susceptible to hemodynamic changes in the setting of intrauterine blood transfusion due to severe anemia. Although the correlation between fetal intracranial anomalies and Parvovirus infection remains unclear, in this population, a detailed evaluation of the brain parenchyma should be considered prior to and after intrauterine blood transfusion.

Sonographic appearance of the epididymis in pediatric testicular torsion.

OBJECTIVE: The purpose of this study was to determine the frequency of an enlarged epididymis in pediatric patients with testicular torsion and to determine whether an altered epididymis might be a helpful ancillary sonographic sign of testicular torsion. MATERIALS AND METHODS: The sonograms of 50 pediatric patients (age range, neonate-17 years) with testicular torsion were retrospectively reviewed for the size, appearance, and blood flow of the epididymis. Medical records were reviewed for surgical and pathologic findings and to determine whether testicular salvage had been possible. RESULTS: The epididymis was enlarged (maximum dimension, 5.5 cm) in 47 of the 50 patients with acute or late phase torsion and after manual or spontaneous detorsion. The average difference in volume between the ipsilateral epididymis and the contralateral epididymis was 30 cm3, highly significant (p < 0.0001). The shape of the epididymis was altered in 92% of the cases (globular, bilobular, or multilobular). Seventy-three percent showed increased echogenicity and 27% appeared isoechoic. Of those with active torsion, 93% of the epididymides were avascular; 2%, hypovascular; and 5%, hypervascular. After detorsion, 100% of the epididymides (10/10) had blood flow. In patients with testicular loss due to infarction, pathology showed engorgement and enlargement of the epididymis with hemorrhagic infarction. In one patient with a hypervascular epididymis, surgery showed inflammation and erythema of the epididymis. Testicular loss occurred in each type of epididymal flow pattern. CONCLUSION: A markedly enlarged, echogenic, and avascular or hypovascular epididymis is an ancillary sonographic sign in pediatric patients with testicular torsion. A hypervascular enlarged epididymis infrequently occurs (5% of cases) and should not be mistaken for epididymitis. In addition, the return of epididymal blood flow is an ancillary sign of successful testicular detorsion.

Prenatal Imaging of the Gastrointestinal Tract with Postnatal Imaging Correlation.

Prenatal detection of a wide variety of anomalies and masses of the gastrointestinal tract is now possible. Prenatal imaging with ultrasonography and in selected cases magnetic resonance imaging provides invaluable information to the referring obstetrician, the maternal fetal medicine specialist, the neonatologist and pediatrician who will care for the child after birth, the surgeons and pediatric specialists who will repair or manage a prenatally detected anomaly, and of course to the parents, allowing them to prepare psychologically and financially for the specific interventions that may be needed for their child. Additional screening for associated anomalies can take place, route of delivery can be decided, and arrangements for delivery in an appropriate setting can be made. Prenatal detection also allows for consideration for pregnancy termination. This article will give a broad overview of anomalies of the gastrointestinal tract that can be detected prenatally and their imaging appearance postnatally.

Ovary and testicle and everything in between: lesions and imaging in the newborn.

Assessment of the neonatal reproductive tract requires an understanding of embryology, awareness of common clinical presentations, and familiarity with normal newborn variation. This review of the neonatal reproductive tract emphasizes the use of sonography in the evaluation of developmental, acquired, and neoplastic conditions in male and female newborns. Anchored in embryologic origins, the discussion also includes descriptions of findings that may be encountered in prenatal imaging. Comments on clinical correlation are included to guide appropriate triaging of these complex cases. Imaging pearls and pitfalls are incorporated into this review, including the recognized effects of maternal hormones in female infants.

Color Doppler sonography and scintigraphy of the testis: a prospective, comparative analysis in children with acute scrotal pain.

OBJECTIVE: To compare testicular color Doppler sonography with testicular scintigraphy in differentiating between surgical and nonsurgical conditions of the pediatric testis, and to evaluate the role of testicular color Doppler sonography in the pediatric population. MATERIALS AND METHODS: Forty-six children (age range, 1 day to 18 years; median age, 11 years) with acute scrotal pain were evaluated with both scintigraphy and color Doppler sonography by two separate groups of radiologists who had no knowledge of the results of the other modality. The final radiologic diagnosis was classified as a surgical condition, nonsurgical condition, or indeterminate and was compared with the patient's surgical diagnosis or clinical diagnosis, which was established by response to treatment and follow-up. RESULTS: Sonography correctly diagnosed 11 of 14 surgical conditions and 31 of 32 nonsurgical conditions. There was one indeterminate sonogram. There were no false-positive examinations, and there were three false-negative examinations (sensitivity = 78.6% [95% CI, 66.7-90.5%], specificity = 96.9% [95% CI, 94.3-99.5%], accuracy = 91.3%). Color flow was demonstrated in the asymptomatic testis in 34 of 44 boys. Scintigraphy correctly diagnosed 11 of 14 surgical conditions and 29 of 32 nonsurgical conditions. There were two indeterminate scintigrams. There were two false-positive examinations and two false-negative examinations (sensitivity = 78.6% [95% CI, 66.7%-90.5%], specificity = 90.6% [95%CI, 82.2%-99.0%], accuracy = 87.0%). CONCLUSIONS: Color Doppler sonography and scintigraphy show similar sensitivity for the diagnosis of testicular torsion. A small number of false-negative cases can occur with either modality. The two studies may provide complementary information in indeterminate cases.