The view from the mastoid fontanel of the neonatal brain

Transcription

1 The view from the mastoid fontanel of the neonatal brain Poster No.: C-0974 Congress: ECR 2016 Type: Educational Exhibit Authors: Y. Pekcevik, F. C. Sarioglu, H. Sahin ; Karabaglar/Izmir/TR, Izmir/TR Keywords: Hemorrhage, Congenital, Artifacts, Normal variants, Education, Ultrasound, MR, Pediatric DOI: /ecr2016/C-0974 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 40

2 Learning objectives To tell how to perform mastoid fontanel imaging To display the normal anatomy seen from the mastoid fontanel view To demonstrate pitfalls and artifacts of the mastoid fontanel imaging To show pathologies of the posterior fossa that can be evaluated with mastoid fontanel imaging To emphasize clinical conditions that adding this approach would help diagnosis and patient management. Images for this section: Page 2 of 40

3 Fig. 1: Normal 3D calvarial anatomy. Mastoid fontanel (red arrow) is located at the junction of the squamosal, lambdoid, and occipital sutures and does not fuse until 2 years of age. F, frontal bone; O, occipital bone; P, parietal bone; Sp, sphenoid bone; Ts, temporal bone squamous portion. Tepecik education and research hospital - Izmir/TR Page 3 of 40

4 Background Survival rates for preterm infants have risen dramatically owing to the latest prenatal and postnatal treatments and modern, well-equipped and well-staffed neonatal intensive care units (1). Cranial sonography (US) is the primary imaging technique for evaluation of the brain in these patients (2-4). Although anterior fontanel imaging is the main imaging approach of the neonatal cranial US, this traditional approach has some limitations in demonstrating posterior fossa pathologies (5). The mastoid fontanel is the thinnest region of the temporal bone at the junction of the squamosal, lambdoid, and occipital sutures and does not fuse until 2 years of age (6). Visualization of posterior fossa anatomy and pathologies of the neonatal brain is best achieved by obtaining images through the mastoid fontanel (Fig. 1). This magic window also gives some information about some supratentorial pathologies. Images for this section: Page 4 of 40

5 Fig. 1: Normal 3D calvarial anatomy. Mastoid fontanel (red arrow) is located at the junction of the squamosal, lambdoid, and occipital sutures and does not fuse until 2 years of age. F, frontal bone; O, occipital bone; P, parietal bone; Sp, sphenoid bone; Ts, temporal bone squamous portion. Tepecik education and research hospital - Izmir/TR Page 5 of 40

6 Findings and procedure details For performing mastoid fontanel imaging and evaluating the imaging findings properly, we should know the answers of these questions. How to perform the mastoid fontanel imaging? 1. Use portable ultrasonography machine: The ultrasonography machine should be portable to allow bedside examinations. It should be equipped with appropriate transducers, especially with a high resolution transducer for neonatal head, Doppler function and a storage system. Obey the neonatal intensive care (NICU) rules: Especially the hygiene rules of the neonatal NICU should be obeyed. The probe should be cleaned before using on each patient. There are a lot of medical equipments in NICU. The position of the lines and tubes and the clinical condition of baby should be cared and watched while performing cranial sonography ( Fig. 2 on page 24 ) 2. Page 6 of 40

7 3. 4. Fig. 2: There are a lot of medical equipments in neonatal intensive care unit. The position of the lines and tubes and clinical condition of the baby should be cared and watched. This patient had seizure and sudden drop in oxygen saturation level while performing cranial ultrasonography (black arrow). References: Tepecik education and research hospital - Izmir/TR Use every window for imaging: It is better to start performing cranial US with anterior fontanel window and subsequently to move on posterior fontanel and the mastoid fontanel window in every patient. Temporal bone window, foramen magnum view can also be used, if needed. For mastoid fontanel imaging, place the transducer behind the ear: The mastoid fontanel imaging can be performed in the side-lying position of patient or just turning the head to one side (the side that is more comfortable for the patient). After placing the transducer behind the ear, it should be slightly moved until a good view of the posterior fossa is obtained (7) ( Fig. 3 on page 25 ). The whole posterior fossa and part of the brain and lateral ventricles can be demonstrated by tilting the transducer gently up and down. Page 7 of 40

8 Fig. 3: For mastoid fontanel imaging, we should place the US transducer behind the ear, and move it slightly until a good view of the posterior fossa is obtained. References: Gerda van Wezel-Meijler: Neonatal Cranial Ultrasonography. Springer, Berlin Heidelberg; 2007:39-41 What should be known about the normal anatomy observed through the mastoid fontanel? 1. Posterior fossa visualization through the anterior fontanel is limited: Part of the cerebellar hemispheres and vermis can be evaluated through the anterior fontanel ( Fig. 4 on page 26 ). But with standard anterior fontanel imaging, cerebellar pathologies, especially cerebellar hemorrhage, can be easily overlooked because of the echogenic tentorium and vermis (8). Page 8 of 40

9 2. Fig. 4: Anterior fontanel view, sagittal image of an infant born at 30 weeks of gestation shows the midline anatomy of the posterior fossa. *Note the anterior aspect of the pons is more echogenic than the posterior aspect. References: Tepecik education and research hospital - Izmir/TR The whole anatomy of the posterior fossa can be evaluated easily from the mastoid fontanel: The normal anatomy observed through the mastoid fontanel should be familiar with for early and accurate diagnosis ( Fig. 5 on page 27 ). Page 9 of 40

10 3. Fig. 5: The normal posterior fossa anatomy seen through the mastoid fontanel. CH, cerebellar hemisphere; CM, cisterna magna; V, vermis; T, tentorium; scc, superior cerebellar cistern. References: Tepecik education and research hospital - Izmir/TR The normal anatomy of the cerebellum changes related to ongoing maturation: The cerebellar hemispheres become more echogenic and have more sulci with increasing gestational age ( Fig. 6 on page 28 ). Page 10 of 40

11 Fig. 6: Mastoid fontanel views of the normal posterior fossa in premature infants born at different weeks. Cerebellar hemispheres become more echogenic and have more sulci with increasing gestational age. The arrowheads indicate tentorium cerebelli. CH, cerebellar hemisphere; CM, cisterna magna; v, vermis; cp, cerebral peduncle; scc, superior cerebellar cistern. References: Tepecik education and research hospital - Izmir/TR What are the pitfalls and artifacts of the mastoid fontanel imaging? 1. Enlarged foramen of Magendi: Enlarged foramen of Magendi due to recent intraventricular hemorrhage may resemble vermian hypoplasia. Imaging the whole cerebellum by tilting the transducer upward reveals the normal vermis ( Fig. 7 on page 29 ). Page 11 of 40

12 2. Fig. 7: Mastoid fontanel view shows enlarged foramen of Magendi due to recent intraventricular hemorrhage that resembles vermian hypoplasia (A). The normal vermis (**) can be seen just by tilting the US transducer upward (B). References: Tepecik education and research hospital - Izmir/TR Mega sisterna magna: Mega cisterna magna (cisterna magna > 8 mm) should not be confused with arachnoid cyst and Dandy-Walker malformation (9). The normal dural folds seen within the cistern magna, and normal vermis and cerebellar hemispheres, both can be evaluated better with mastoid fontanel imaging, allows distinguishing this normal variant from pathologies ( Fig. 8 on page 30 ). Page 12 of 40

13 3. Fig. 8: Anterior fontanel view sagittal image and mastoid fontanel view demonstrate mega cisterna magna (red arrows). Cerebellar hemispheres and vermis are normal. The mastoid fontanel view shows dural folds within the cistern (arrowhead). Normal anatomy of the cisterna magna is shown in the right and left upper corners for comparison (white arrows). References: Tepecik education and research hospital - Izmir/TR Artifacts due to occipital bone: Occipital bones are strong parallel reflectors and when a sound pulse reverberates back and forth from these bones, a kind of reverberation artifact may occur. Care should be taken while evaluating the posterior fossa from the mastoid fontanel, because these artifacts may be misinterpreted as cerebellar hemorrhage. By changing the tilt of the transducer, the normal cerebellar hemispheres will show up ( Fig. 9 on page 30 ). Page 13 of 40

14 Fig. 9: Mastoid fontanel view shows an artifact that may be misinterpreted as cerebellar hemorrhage (arrows) (A). Now by changing the tilt of the transducer, the normal cerebellar hemispheres look normal (B). Occipital bones (arrows) are strong parallel reflectors and when a sound pulse reverberates back and forth, a kind of reverberation artifact may occur. References: Tepecik education and research hospital - Izmir/TR How can we evaluate the cerebellar hemorrhage and why does it matter? 1. Cerebellar hemorrhage should be evaluated in all premature infants: Cerebellar hemorrhage is a germinal matrix hemorrhage derived from the external granular layer of the cerebellum in extremely preterm infants (10). It especially occurs in premature infants born between weeks. Cerebellar hemorrhage is best evaluated through mastoid fontanel: Cerebellar hemorrhage is usually circular or lentiform in shape and is located primarily at the inferior and posterior peripheral regions of the cerebellar hemisphere ( Fig. 10 on page 31 ). It can be easily overlooked while standard anterior fontanel imaging. 2. Page 14 of 40

15 3. Fig. 10: Mastoid fontanel view demonstrates cerebellar hemorrhage (arrows) located at the inferior peripheral region of the cerebellar hemisphere. Arrowheads indicate tentorium. Normal anatomy of the posterior fossa is shown in the left upper corner for comparison. CH, cerebellar hemisphere; 4, forth ventricle; CM, cistern magna; v, vermis. References: Tepecik education and research hospital - Izmir/TR Cerebellar hemorrhage is usually associated with germinal matriksintraventricular hemorrhage: Cerebellar hemorrhage is usually associated with intraventricular hemorrhage with ventricular dilatation (grade 3 hemorrhage) and periventricular hemorrhagic infarction (grade 4 hemorrhage) (8, 10) ( Fig. 11 on page 31 ). But it can occur with any kind of germinal matrix hemorrhage, including a small subependymal hemorrhage (grade 1 hemorrhage) (Fig. 12) Page 15 of 40

16 Fig. 11: Mastoid fontanel view shows bilateral extensive cerebellar hemorrhages (white arrows). Associated bilateral intraventricular hemorrhage with ventricular dilatation is also seen with mastoid fontanel imaging (red arrows). Normal anatomy of the posterior fossa is shown in the right upper corner for comparison. CH, cerebellar hemisphere; CM, cistern magna; v, vermis. References: Tepecik education and research hospital - Izmir/TR Page 16 of 40

17 4. Fig. 12: Anterior fontanel view, coronal image demonstrates the left subependymal germinal matrix hemorrhage (grade 1 hemorrhage) (arrowhead). Mastoid fontanel view shows associated cerebellar hemorrhage located at the inferior peripheral region of the cerebellar hemisphere (white arrows). References: Tepecik education and research hospital - Izmir/TR Cerebellar cysts located at the peripheral region of cerebellar hemispheres in premature infants are usually due to recent cerebellar hemorrhage: Cerebellar hemorrhage progressively lose its echogenicity over time and then usually becomes intraparenchymal cyst ( Fig. 13 on page 33 ). Magnetic resonance (MR) imaging is better at demonstrating the evidence of hemorrhage with gradient-echo T2*-weighted images or susceptibilityweighted imaging. Page 17 of 40

18 5. 6. Fig. 13: Mastoid fontanel view demonstrates cerebellar cyst (white arrow) located at the peripheral region of the cerebellar hemisphere. Hypointense signals due to blood products in the gradient-echo T2*-weighted image (red arrow) confirms the recent cerebellar hemorrhage. Normal anatomy of the posterior fossa is shown in the right upper corner for comparison. CH, cerebellar hemisphere; CM, cistern magna; scc, superior cerebellar cistern. References: Tepecik education and research hospital - Izmir/TR Cerebellar hemorrhage is the leading cause of the unilateral cerebellar hypoplasia and cerebellar clefts: Unilateral cerebellar hypoplasia is characterized by variable volume loss in the cerebellar hemisphere and vermis, with a normal-sized posterior fossa (11). Evidence of prior hemorrhage may be present and is best demonstrated with gradient-echo T2*-weighted images or susceptibility-weighted imaging. But the absence of hemosiderin does not exclude hemorrhage, because the blood-brain barrier is permeable to hemosiderin-laden macrophages between weeks gestation (11, 12). Cerebellar clefts represent residual disruptive changes and seen as a cleft that extends from the surface of the cerebellum to the fourth ventricle, with volume loss and abnormal cerebellar foliation (11, 12). Supratentorial descructive pathologies such as porencephalic cysts and schizencephaly may support diagnosis (11). Cerebellum is not only responsible motor and balance functions but also cognitive functions: Preterm infants with cerebellar hemorrhage carry longterm risk of motor disability and cognitive impairment (11). That is why the diagnosis of cerebellar hemorrhage is important. Page 18 of 40

19 Can we evaluate congenital malformations of the posterior fossa with mastoid fontanel imaging? 1. Posterior fossa morphology and malformations can be evaluated with mastoid fontanel imaging: Although MR imaging is a better tool for diagnosis of posterior fossa malformations, high resolution images can be obtained, especially in patients with cystic malformations of the posterior fossa, with mastoid fontanel imaging that may resemble MR images Dandy-Walker malformation: Dandy-Walker malformation is the most common malformation of the posterior fossa and characterized with dilatation of the cystic appearing fourth ventricle, and a small and upwardly rotated cerebellar vermis (13) ( Fig. 14 on page 34 ) Fig. 14: Dandy-Walker malformation. Anterior fontanel view, sagittal image demonstrates the small and upwardly rotated cerebellar vermis. Mastoid fontanel view shows large posterior fossa associated with dilatation of the cystic appearing fourth ventricle. T1- weighted sagittal (right upper corner) and T2-weighted axial (left upper corner) images of the same patient are shown for comparison. References: Tepecik education and research hospital - Izmir/TR Joubert syndrome: Joubert syndrome is characterized with the "molar tooth sign" that represents elongated, thickened, and horizontally oriented superior cerebellar peduncles; a deep interpeduncular fossa; and small, dysplastic cerebellar vermis with a midline cleft (14, 15) ( Fig. 15 on page 34 ). Page 19 of 40

20 4. Fig. 15: Joubert syndrome. Mastoid fontanel views show small and dysplastic cerebellar vermis with a superior midline cerebellar cleft (arrows). T2- weighted axial (right upper corner) and T1-weighted axial (left upper corner) images of the same patient demonstrate the "molar tooth sign" and small, dysplastic cerebellar vermis with a superior midline cleft. References: Tepecik education and research hospital - Izmir/TR Chiari 2 malformation: Evaluation of the posterior fossa pathologies is limited in Chiari 2 due to small posterior fossa. But very small posterior fossa with obliteration of cisterna magna and fourth ventricle, upward herniation of the cerebellum through tentorial incisura, herniation of the cerebellar vermis through foramen magnum, along with the typical supratentorial US findings (squared, box-like shape frontal horns, anterior-inferior pointing of the frontal horns with colpocephaly) help diagnosis (16) ( Fig. 16 on page 35 ). Page 20 of 40

21 Fig. 16: Chiari 2 malformation. Anterior fontanel view, coronal and sagittal images demonstrate squared, box-like shape of the frontal horns (arrowheads) that is attributed to the absence of the septum pellicidum, and anterior-inferior pointing of the frontal horns (arrowhead) with colpocephaly. Mastoid fontanel view shows very small posterior fossa with obliteration of cisterna magna and fourth ventricle, and upward herniation of the cerebellum through tentorial incisura (arrows). References: Tepecik education and research hospital - Izmir/TR Does adding the mastoid fontanel imaging help diagnosis of supratentorial pathologies? 1. Clot in the cisterna magna: Obliteration of the cisterna magna with hyperechoic clot in the presence of germinal matrix-intraventricular hemorrhage is best evaluated through mastoid fontanel window. Clot in the cisterna magna represents increased risk of posthemorrhagic ventricular dilatation (17). ( Fig. 17 on page 36 ) Page 21 of 40

22 2. Fig. 17: Mastoid fontanel view shows hyperechoic clot in the cistern magna (arrow), which represents increased risk of posthemorrhagic ventricular dilatation. Intraventricular hemorrhage with ventricular dilatation can also be evaluated (arrowheads). Normal anatomy of the posterior fossa is shown in the left upper corner for comparison. CH, cerebellar hemisphere; CM, cistern magna; v, vermis. References: Tepecik education and research hospital - Izmir/TR Intraventricular hemorrhage and clot can be evaluated by mastoid fontanel imaging: If the transducer angled semicoronally, thalami, midbrain, third ventricle and part of the lateral ventricles and cerebral hemisphere can be evaluated and a small hemorrhage may be picked up ( Fig. 18 on page 36 ). Imaging from mastoid fontanel can also be useful in patients that anterior fontanel images could not be obtained because of limited access, such as presence of the scalp vein catheterization near anterior fontanel localization. Page 22 of 40

23 Fig. 18: Mastoid fontanel view demonstrates intraventricular hemorrhage with ventricular dilatation (arrows) and hyperechoic thickened ependyma (small arrows) that is attributed to the chemical ventriculitis secondary to hemorrhage. There is also hyperechoic clot in the cistern magna (arrowhead). References: Tepecik education and research hospital - Izmir/TR Page 23 of 40

24 Images for this section: Fig. 1: Normal 3D calvarial anatomy. Mastoid fontanel (red arrow) is located at the junction of the squamosal, lambdoid, and occipital sutures and does not fuse until 2 years of age. F, frontal bone; O, occipital bone; P, parietal bone; Sp, sphenoid bone; Ts, temporal bone squamous portion. Tepecik education and research hospital - Izmir/TR Page 24 of 40

25 Fig. 2: There are a lot of medical equipments in neonatal intensive care unit. The position of the lines and tubes and clinical condition of the baby should be cared and watched. This patient had seizure and sudden drop in oxygen saturation level while performing cranial ultrasonography (black arrow). Tepecik education and research hospital - Izmir/TR Page 25 of 40

26 Fig. 3: For mastoid fontanel imaging, we should place the US transducer behind the ear, and move it slightly until a good view of the posterior fossa is obtained. Gerda van Wezel-Meijler: Neonatal Cranial Ultrasonography. Springer, Berlin Heidelberg; 2007:39-41 Page 26 of 40

27 Fig. 4: Anterior fontanel view, sagittal image of an infant born at 30 weeks of gestation shows the midline anatomy of the posterior fossa. *Note the anterior aspect of the pons is more echogenic than the posterior aspect. Tepecik education and research hospital - Izmir/TR Page 27 of 40

28 Fig. 5: The normal posterior fossa anatomy seen through the mastoid fontanel. CH, cerebellar hemisphere; CM, cisterna magna; V, vermis; T, tentorium; scc, superior cerebellar cistern. Tepecik education and research hospital - Izmir/TR Page 28 of 40

29 Fig. 6: Mastoid fontanel views of the normal posterior fossa in premature infants born at different weeks. Cerebellar hemispheres become more echogenic and have more sulci with increasing gestational age. The arrowheads indicate tentorium cerebelli. CH, cerebellar hemisphere; CM, cisterna magna; v, vermis; cp, cerebral peduncle; scc, superior cerebellar cistern. Tepecik education and research hospital - Izmir/TR Fig. 7: Mastoid fontanel view shows enlarged foramen of Magendi due to recent intraventricular hemorrhage that resembles vermian hypoplasia (A). The normal vermis (**) can be seen just by tilting the US transducer upward (B). Tepecik education and research hospital - Izmir/TR Page 29 of 40

30 Fig. 8: Anterior fontanel view sagittal image and mastoid fontanel view demonstrate mega cisterna magna (red arrows). Cerebellar hemispheres and vermis are normal. The mastoid fontanel view shows dural folds within the cistern (arrowhead). Normal anatomy of the cisterna magna is shown in the right and left upper corners for comparison (white arrows). Tepecik education and research hospital - Izmir/TR Page 30 of 40

31 Fig. 9: Mastoid fontanel view shows an artifact that may be misinterpreted as cerebellar hemorrhage (arrows) (A). Now by changing the tilt of the transducer, the normal cerebellar hemispheres look normal (B). Occipital bones (arrows) are strong parallel reflectors and when a sound pulse reverberates back and forth, a kind of reverberation artifact may occur. Tepecik education and research hospital - Izmir/TR Fig. 10: Mastoid fontanel view demonstrates cerebellar hemorrhage (arrows) located at the inferior peripheral region of the cerebellar hemisphere. Arrowheads indicate tentorium. Normal anatomy of the posterior fossa is shown in the left upper corner for comparison. CH, cerebellar hemisphere; 4, forth ventricle; CM, cistern magna; v, vermis. Tepecik education and research hospital - Izmir/TR Page 31 of 40

32 Fig. 11: Mastoid fontanel view shows bilateral extensive cerebellar hemorrhages (white arrows). Associated bilateral intraventricular hemorrhage with ventricular dilatation is also seen with mastoid fontanel imaging (red arrows). Normal anatomy of the posterior fossa is shown in the right upper corner for comparison. CH, cerebellar hemisphere; CM, cistern magna; v, vermis. Tepecik education and research hospital - Izmir/TR Page 32 of 40

33 Fig. 12: Anterior fontanel view, coronal image demonstrates the left subependymal germinal matrix hemorrhage (grade 1 hemorrhage) (arrowhead). Mastoid fontanel view shows associated cerebellar hemorrhage located at the inferior peripheral region of the cerebellar hemisphere (white arrows). Tepecik education and research hospital - Izmir/TR Fig. 13: Mastoid fontanel view demonstrates cerebellar cyst (white arrow) located at the peripheral region of the cerebellar hemisphere. Hypointense signals due to blood products in the gradient-echo T2*-weighted image (red arrow) confirms the recent Page 33 of 40

34 cerebellar hemorrhage. Normal anatomy of the posterior fossa is shown in the right upper corner for comparison. CH, cerebellar hemisphere; CM, cistern magna; scc, superior cerebellar cistern. Tepecik education and research hospital - Izmir/TR Fig. 14: Dandy-Walker malformation. Anterior fontanel view, sagittal image demonstrates the small and upwardly rotated cerebellar vermis. Mastoid fontanel view shows large posterior fossa associated with dilatation of the cystic appearing fourth ventricle. T1weighted sagittal (right upper corner) and T2-weighted axial (left upper corner) images of the same patient are shown for comparison. Tepecik education and research hospital - Izmir/TR Page 34 of 40

35 Fig. 15: Joubert syndrome. Mastoid fontanel views show small and dysplastic cerebellar vermis with a superior midline cerebellar cleft (arrows). T2- weighted axial (right upper corner) and T1-weighted axial (left upper corner) images of the same patient demonstrate the "molar tooth sign" and small, dysplastic cerebellar vermis with a superior midline cleft. Tepecik education and research hospital - Izmir/TR Fig. 16: Chiari 2 malformation. Anterior fontanel view, coronal and sagittal images demonstrate squared, box-like shape of the frontal horns (arrowheads) that is attributed to the absence of the septum pellicidum, and anterior-inferior pointing of the frontal horns (arrowhead) with colpocephaly. Mastoid fontanel view shows very small posterior fossa with obliteration of cisterna magna and fourth ventricle, and upward herniation of the cerebellum through tentorial incisura (arrows). Page 35 of 40

36 Tepecik education and research hospital - Izmir/TR Fig. 17: Mastoid fontanel view shows hyperechoic clot in the cistern magna (arrow), which represents increased risk of posthemorrhagic ventricular dilatation. Intraventricular hemorrhage with ventricular dilatation can also be evaluated (arrowheads). Normal anatomy of the posterior fossa is shown in the left upper corner for comparison. CH, cerebellar hemisphere; CM, cistern magna; v, vermis. Tepecik education and research hospital - Izmir/TR Page 36 of 40

37 Fig. 18: Mastoid fontanel view demonstrates intraventricular hemorrhage with ventricular dilatation (arrows) and hyperechoic thickened ependyma (small arrows) that is attributed to the chemical ventriculitis secondary to hemorrhage. There is also hyperechoic clot in the cistern magna (arrowhead). Tepecik education and research hospital - Izmir/TR Page 37 of 40

38 Conclusion For mastoid fontanel imaging, place the transducer behind the ear, slightly moved the transducer until a good view of the posterior fossa is obtained. The whole posterior fossa, thalami, midbrain, third ventricle, and part of the brain cerebellar hemispheres and lateral ventricles can be demonstrated by tilting the transducer gently upward and downward. The normal anatomy observed through the mastoid fontanel should be familiar with for early and accurate diagnosis. Enlarged foramen of Magendi, mega cistern magna and artifacts of the occipital bones should not be confused with posterior fossa pathologies. Cerebellar hemorrhage can be evaluated through mastoid fontanel and it is important for predicting long-term neurodevelopmental outcome of the premature infant. Posterior fossa morphology and malformations, especially cystic malformations of the posterior fossa, can be evaluated with mastoid fontanel imaging. Adding mastoid fontanel imaging helps diagnosis of the supratentorial pathologies. Personal information Yeliz Pekcevik, MD Tepecik Training and Research Hospital, Department of Radiology, Izmir, Turkey Fatma Ceren Sarioglu, MD Tepecik Training and Research Hospital, Department of Radiology, Izmir, Turkey Hilal Sahin, MD Tepecik Training and Research Hospital, Department of Radiology, Izmir, Turkey Page 38 of 40

39 References References: Doyle LW, Anderson PJ. Adult outcome of extremely preterm infants. Pediatrics 2010;126:342. Lowe LH, Bailey Z. State-of-the-art cranial sonography: Part 1, modern techniques and image interpretation. AJR Am J Roentgenol 2011;196:1028. Daneman A, Epelman M, Blaser S, et al. Imaging of the brain in full-term neonates: does sonography still play a role? Pediatr Radiol 2006;36:636. Epelman M, Daneman A, Kellenberger CJ, et al. Neonatal encephalopathy: a prospective comparison of head US and MRI. Pediatr Radiol 2010;40:1640. Di Salvo DN. A new view of the neonatal brain: clinical utility of supplemental neurologic US imaging windows. Radiographics 2001;21: Pekcevik Y, Ozer EA, Guleryuz H. Cranial sonography in extremely preterm infants. J Clin Ultrasound. 2014;42: Gerda van Wezel-Meijler: Neonatal Cranial Ultrasonography. Springer, Berlin Heidelberg; 2007: Soudack M, Jacobson J, Raviv-Zilka L, et al. Cerebellar hemorrhage in very low birth weight premature infants: the advantage of the posterolateral fontanelle view. J Clin Ultrasound 2013;41: Lowe LH, Bailey Z. State-of-the-art cranial sonography: Part 2, pitfalls and variants. AJR Am J Roentgenol 2011;196:1034. Limperopoulos C, Benson CB, Bassan H, et al. Cerebellar hemorrhage in the preterm infant: ultrasonographic findings and risk factors. Pediatrics 2005;116:717. Bosemani T, Orman G, Boltshauser E, Tekes A, Huisman TA, Poretti A. Congenital abnormalities of the posterior fossa. Radiographics 2015;35: Poretti A, Prayer D, Boltshauser E. Morphological spectrum of prenatal cerebellar disruptions. Eur J Paediatr Neurol 2009;13: Doherty D, Millen KJ, Barkovich AJ. Midbrain and hindbrain malformations: advances in clinical diagnosis, imaging, and genetics. Lancet Neurol 2013;12: Poretti A, Huisman TA, Scheer I, Boltshauser E. Joubert syndrome and related disorders: spectrum of neuroimaging findings in 75 patients. AJNR Am J Neuroradiol 2011;32: Patel S, Barkovich AJ. Analysis and classification of cerebellar malformations. AJNR Am J Neuroradiol. 2002;23: Page 39 of 40

40 16. Chapman T, Mahalingam S, Ishak GE, Nixon JN, Siebert J, Dighe MK. Diagnostic imaging of posterior fossa anomalies in the fetus and neonate: part 2, Posterior fossa disorders. Clin Imaging 2015;39: Cramer BC, Walsh EA. Cisterna magna clot and subsequent posthemorrhagic hydrocephalus. Pediatr Radiol 2001;31: Page 40 of 40