virtual bronchoscopy for evaluating cervical tumors of the fetus

7/28/2019 Virtual Bronchoscopy for Evaluating Cervical Tumors of the Fetus

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Copyright 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Virtual Bronchoscopy for Evaluating Cervical Tumors of the Fetus

Heron Werner 1,3, Jorge R. Lopes dos Santos 2,5, Ricardo Fontes 2,5, Simone

Belmonte 2, Pedro Daltro 1,3,4, Emerson Gasparetto 1,3, Edson Marchiori 3,

Stuart Campbell

6

1. Clnica de Diagnstico por Imagem (CDPI), Rio de Janeiro, Brazil.2. Instituto Nacional de Tecnologia (INT), Rio de Janeiro, Brazil.3. Department of Radiology, Universidade Federal do Rio de Janeiro (UFRJ),Rio de Janeiro, Brazil.4. Instituto Fernandes Figueira (IFF), Rio de Janeiro, Brazil.5. Pontificia Universidade Catlica do Rio de Janeiro, Brazil.

6. Create Health Clinic, London, UK.*Correspondence.(e-mail: [email protected])Abstract

We report four cases of cervical tumors (three lymphangiomas and oneteratoma) evaluated by ultrasound and magnetic resonance imaging (MRI)

between 26 and 37 weeks gestation. The aim was to investigate the use of

Virtual Bronchoscopy (VB) to evaluate fetal airway patency on each case. A 3D

file of the airway was created by overlapping layers generated by MRI. The 3D

files were converted into an OBJ extension using the 3D modeling software

MAYA (Autodesk, USA). This allowed the virtual positioning of observation

cameras while working with multiple windows. Using the indoor and outdoor

lighting features, 3D simulation movies were generated for analysis of a virtual

path. In all fetuses, fetal airway patency was clearly demonstrated by VB. MRI

This article has been accepted for publication and undergone full scientific peer review but has not

been through the copyediting, typesetting, pagination and proofreading process which may lead to

differences between this version and the Version of Record. Please cite this article as an Accepted

Article, doi: 10.1002/uog.11162.


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with VB could become a useful tool for studying fetal airway patency in cases of

cervical tumor.

Keywords: fetus, cervical tumors, ultrasound, magnetic resonance imaging,

virtual bronchoscopy

Case Reports

Four fetuses with a cervical tumor (three lymphangiomas and one

teratoma) were evaluated in our Tertiary Imaging Center (Clnica de

Diagnstico por Imagem) in Rio de Janeiro between September 2010 and

March 2011 by ultrasound (US) and magnetic resonance imaging (MRI) (Table

1). All cases were examined first by US on the same day of MRI. The ethical

issues associated with this work were considered and approved by our research

ethics committee (CEPIFF: 0012/10).

The main outcome of this study was the creation of 3D virtual airway

paths from fetuses with cervical tumors, and performing Virtual Bronchoscopy

(VB) based on those images. The median gestational age of the fetuses with

cervical tumors diagnosed by US in this study was 24.7 weeks (range 22-27

weeks). MRI was performed between 26 and 37 weeks. In case 2, MRI was

performed twice, at 26 and 37 weeks. The mean tumor diameters observed by

US and MRI are recorded in Table 2. Polyhydramnios was detected only in

case 2. In all cases, VB was successful, showing the absence of tumor invasion

or tracheal distortion or compression (Figures 1-4;videos1-4)). The mean time

to perform a VB after MRI was 2 hours. In two cases (2 and 3), postnatal

surgery to remove the tumor was performed. In cases 1 and 4, treatment with

OK 432 was performed, with successful results to date. All fetuses had normal

karyotypes. Babies were delivered by cesarean section after 36 weeks

gestation. EXIT and tracheostomy were not necessary. All neonates had good

outcomes (Table 3).


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US scans included 3D imaging and were performed transabdominally

using a high-resolution US probe with harmonic imaging for all examinations (4-

8 MHz transducer, Voluson 730 Pro/Expert system, General Electric,

Kretztechnik, Zipf, Austria).

MRI examination was performed using a 1.5-T scanner (Siemens,

Erlangen, Germany). The protocol used was a T2-weighted sequence in the

three planes of the fetal body (HASTE; repetition time, shortest; echo time, 140

ms; field of view, 300200 mm; 256 256 matrix; slice thickness, 4 mm;

acquisition time, 17 s; 40 slices) 1. A T1-weighted sequence was taken for three

planes of the fetal body (repetition time, shortest; echo time, 140 ms; field of

view, 300200 mm; 256 256 matrix; slice thickness, 4 mm; acquisition time,

17 s; 40 slices). Additionally, a three-dimensional (3D) T2-weighted truefispsequence in the sagittal plane (trufi, TR/TE = 3.02/1.34, voxel size 1.6 x 1.6 x

1.6 mm3, FA = 70, PAT 2, acquisition time = 0.26 s) was applied. The entire

examination time did not exceed 40 min 1,2.

A 3D file of the airway, using overlapping image layers from the MRI, was

created by using the software Mimics (Materialize, Leuven, Belgium). To

separate by contrast differences, output 3D files were generated of areas of

interest, exported as standard triangular language (STL) files, and convertedinto OBJ extensions using the 3D modeling software MAYA (Autodesk, USA) 2.

Discussion

Although the incidence of fetal congenital cervical tumors is low, US is

effective for identifying such tumors3. They tend to be large and can encircle

essential structures such as the esophagus, thyroid, and trachea, making it

impossible for a newborn to breath after birth. Estimation of the degree of

tracheal compression or distortion allows multidisciplinary planning for delivery

and neonatal resuscitation4,5.


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Lymphangioma is a benign congenital malformation of the lymphatic

system that has the potential to infiltrate surrounding structures. It constitutes

approximately 5% to 6% of all benign lesions in childhood and adolescence 5. It

occurs most frequently in the head, neck or axilla 6. The prognosis depends on

the presence of other associated features such as skin edema, hydrops and

polyhydramnios, abnormal karyotype, location and extent of the lesion 5.

Cervical teratoma is a rare congenital tumor that tends to be large, and is

usually solid/cystic. It has an incidence of 1 in 20,00040,000 live births,

accounting for about 6% of all fetal teratomas. Airway obstruction in the

newborn as determined by tracheal compression or occlusion is reported to be

the reason for an 80100% mortality rate in the neonatal period4,5.

Recently, the ability to diagnose fetal tumors in the prenatal period has

improved greatly because of technical advances in imaging7. Early diagnosis

and determination of tumors may affect prognosis, making it possible for babies

with fetal tumors to be saved. US is the method of choice for fetal evaluation

because of its low cost, real-time capability, and non-invasiveness. Cervical

tumors are usually diagnosed in the second and third trimesters of gestation,

and identified as multiseptated, thin-walled cystic masses in the fetal neck. MRI

is a valuable complementary method to US for diagnosing fetal malformations

8

.Technical developments in this imaging modality have greatly improved fetal

imaging, with increasingly rapid sequencing and reduction of fetal motion

artifacts1,7.

The initial stage of cervical tumor treatment involves careful monitoring of

the mother and fetus, with the development of a surgical plan4,5. Ideally the

treatment will be by a multidisciplinary team of medical professionals including a

radiologist, a perinatologist, and a pediatric surgeon. In some cases, surgery isperformed immediately after the baby is delivered by Cesarean section followed

by an EXIT procedure. This gives the surgeon time to perform multiple

procedures to secure the babys airway while preserving the blood flow and gas

exchange that normally occurs between the fetus and the placenta5,9.


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VB is based on MRI archives providing net images of the fetal airway2. It

generates representations of the bronchial tree and surrounding structures from

spatial information derived from imaging sources rather than the bronchoscope

itself10,11. Several software options generate accurate and realistic renderings of

the bronchial tree that can confirm previous MRI findings12

.To perform a VB, a 3D file of the airway is created from overlapping MRI

image layers, which allows separation by contrast difference and by area of

interest. This generates 3D files that are exported as STL files and converted

into OBJ extensions using the 3D modeling software MAYA (Autodesk, USA).

This program allows the virtual positioning of observation cameras while

working with multiple windows. Controlling the indoor and outdoor lighting

features allows the production of 3D simulation movies for analysis of a virtualpath 2.

In the cases in this study, US was used to monitor amniotic fluid volume,

tumor size, and overall fetal well being. MRI provided good information about

both the anatomy and extension of the tumors and helped in the evaluation of

encircled structures and in the study of fetal airway patency by means ofVB.

These examples show that MRI with VB in the third trimester of pregnancy can

be an important tool for planning the mode of delivery and for studying fetalairway patency for fetuses with a cervical mass. In the four cases described

here the outcome was anticipated to be favorable because VB demonstrated an

unobstructed airway. Further studies will demonstrate whether VB is useful in

optimizing outcome when the fetal airway is compromised.


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References

1. Werner H, Dos Santos JRL; Fontes R, Daltro P, Gasparetto E, MarchioriE, Campbell S. Additive manufacturing models of fetuses built fromthree-dimensional ultrasound, magnetic resonance imaging andcomputed tomography scan data. Ultrasound Obstet Gynecol 2010; 36:

355361.2. Werner H, Dos Santos JRL; Fontes R, Daltro P, Gasparetto E, Marchiori

E, Campbell S. Virtual bronchoscopy in the fetus. Ultrasound ObstetGynecol 2011; 37: 113-115.

3. Frates M, Kumar AJ, Benson CB, Ward VL, Tempany CM. Fetalanomalies: comparison of MR imaging and US for diagnosis. Radiology2004; 232: 398-404.

4. Azizkhan RG, Haase GM, Applebaum H, Dillon PW, Coran AG, King PA,King DR, Hodge DS. Diagnosis, management, and outcome ofcervicofacial teratomas in neonates: a childrens cancer group study. JPediatr Surg 1995; 30: 312316.

5. Woodward PJ, Sohaey R, Kennedy A, Koeller K. A comprehensivereview of fetal tumors with pathologic correlation. Radiographics. 2005;25: 215242.

6. Sanlialp I, Karnak I, Tanyel FC, Senocak ME, Buyukpamukcu N.Sclerotherapy for lymphangioma in children. Int J PediatrOtorhinolaryngol. 2003; 67(7): 795-800.

7. Prayer D, Brugger PC, Prayer L. Fetal MRI: techniques and protocols.Pediatr Radiol 2004; 34: 685693.

8. Kathary N, Bulas DI, Newman KD, Schonberg RL. MR imaging of fetalneck masses with airway compromise: utility in delivery planning. PediatrRadiol 2001; 31: 727-731.

9. Luzzatto C, Lo Piccolo R, Leon FF, Zanon GF, Toffolutti T, Tregnaghi A.

Further experience with OK-432 for limphangiomas. Pediatr Surg Int.2005; 21: 969-972.10. Ferguson JS, McLennan G. Virtual bronchoscopy. Proc Am Thorac Soc.

2005; 2: 488491.11. Lam WW, Tam PKH, Chan FL, Chan K, Cheng W. Esophageal atresia

and tracheal stenosis: Use of three-dimensional CT and virtualbronchoscopy in neonates, infants, and children. AJR 2000; 174: 10091012.

12. Merritt SA, Gibbs JD, Yu KC, Patel V, Rai L, Cornish DC, Bascom R,Higgin WE. Image-guided bronchoscopy for peripheral lung lesions.Chest 2008; 134: 10171026.


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Table 1.

Cases Maternal age

(years)

Gestational age

(weeks) US

diagnosis

Gestational age

(weeks) MRI +

VB

Gestational age

at delivery

(weeks)

1 27 27 27 36

2 31 24 26/37 38

3 35 22 36 38

4 27 26 31 39

Case 2: 2 MRI (26 and 37 weeks).


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Table 2.

Cases Tumor US: Mean

tumor

diameter

(mm)

MRI: Mean

tumor

diameter

(mm)

Invasion Development of

polyhydramnios

1 Lymphangioma 63 70 No No

2 Teratoma 60/94 62/91 No/No Yes/Yes




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Table 3.

Cases Weight

(g)

Apgar Sex Tracheostomy EXIT Pregnancy

outcome

Post

natal

surgery

1 2850 7 / 9 Female No No Live birth No

2 3210 6 / 8 Male No No Live birth Yes

3 2910 7 / 9 Female No No Live birth Yes

4 3150 9 / 9 Female No No Live birth No


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Figures

Figure 1: Lymphangioma (case 1). Facial profile illustrated by ultrasound and

MRI (a). Three dimensional (3D) view of the fetal airway and lungs obtained by

MRI (b). Neonate (c).

Figure 2: Cervical teratoma (case 2). Sagittal view of the fetus by MRI and 3D

MRI (a). 3D view of the airway path and a still image from virtual bronchoscopy

showing the airway patency (b). 3D model of the fetus obtained by MRI and the

neonate (c).

Figure 3: 3D view of the lymphangioma (case 3) obtained by ultrasound and

coronal MRI T2 view of the fetus (a). 3D view obtained by MRI showing the

tumor close to the unobstructed airway path and the neonate.

Figure 4: Coronal T2 view (case 4), 3D airway path reconstruction and neonate.

Video 1: Virtual bronchoscopy (VB) (case 1).



Video 4a,b: Virtual bronchoscopy (VB) (case 4). In video 4a, look at the camera

going into the airways of the fetus.


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Acknowledgments

We would like to thank Drs. Romeu Domingues, Maene Marcondes, Mrcio

Bernardes da Silva and Fernando Maia Peixoto for their assistance.


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Figure 1a


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Figure 1b


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Figure 1c


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Figure 2a


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Figure 2b


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Figure 2c


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Figure 3a


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Figure 3b


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Figure 4

virtual bronchoscopy for evaluating cervical tumors of the fetus

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