The Egyptian Journal of Radiology and Nuclear Medicine (2013) 44, 101–111

Egyptian Society of Radiology and Nuclear Medicine

The Egyptian Journal of Radiology andNuclearMedicine

www.elsevier.com/locate/ejrnmwww.sciencedirect.com

ORIGINAL ARTICLE

Multidetector computed tomography evaluation

in neonatal respiratory distress: Clinical implication

Eman Abo Elhamd a, Gehan S. Seifeldein a,*, Nafisa H.R. AbdelAziz b

a Department of Radiology, Assiut University Hospital, Egyptb Department of Pediatrics, Assiut University Children Hospital, Egypt

Received 8 June 2012; accepted 11 December 2012Available online 16 January 2013

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KEYWORDS

Neonatal respiratory dis-

tress;

MDCT;

Multiplanar images;

3D images

Corresponding author. Addr

ty of Medicine, Assiut univermail address: gehanseifeldein

er review under responsibilit

d Nuclear Medicine.

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78-603X � 2012 Egyptian So

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Abstract Objective: To assess the value of multiplanar reformation (MPR) and three-dimensional

multidetector computed tomography (MDCT) images in evaluating respiratory distress in neonates.

Materials and methods: Sixteen neonates (630 days) who presented with respiratory distress (RD)

and admitted in the neonatal intensive care unit of the Assuit university children hospital who were

selected from a total of 1295 patients presented with RD in whom chest X-ray was inconclusive, so

those 16 neonates underwent 64-rows MDCT in the period between November 2010 and November

2011. The recruited patients were sedated before examination and IV contrast medium administra-

tion was needed when there was suspected vascular anomaly. Scans were performed in supine posi-

tion to cover the root of the neck down to the level of the adrenal glands. The images were sent to

the workstation to be reviewed in the multiplanar and 3D images.

Results: The final radiologic diagnoses included cystic adenomatoid malformation (n = 4, 25%),

congenital lobar emphysema (n= 1, 7%), pneumonia (n = 5, 36%), hypoplastic lung (n= 3,

22%), diaphragmatic hernia (n= 2, 14%) and postoperative hydro-pneumothorax (n= 1, 7%).

Conclusion: The combination of fast speed, high spatial resolution, and enhanced quality of MPR

and 3D images makes MDCT an ideal non-invasive method for evaluating surgical causes of neo-

natal respiratory distress.� 2012 Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V.

Open access under CC BY-NC-ND license.

iodiagnosis Department, Fac-

pital, Assiut, Egypt..com (G.S. Seifeldein).

gyptian Society of Radiology

g by Elsevier

Radiology and Nuclear Medicine.

://dx.doi.org/10.1016/j.ejrnm.2012

1. Introduction

The clinical presentation of respiratory distress in the newbornincludes apnea, cyanosis, grunting, inspiratory stridor, nasalflaring, poor feeding, and tachypnea (more than 60 breaths

per minute). There may also be retractions in the intercostal,subcostal, or supracostal spaces. Respiratory distress occursin approximately seven percent of infants (1). Most cases are

caused by transient tachypnea of the newborn, respiratorydistress syndrome, or meconium aspiration syndrome, but

Production and hosting by Elsevier B.V. All rights reserved.

.12.006

102 E.A. Elhamd et al.

various other causes are possible such as pneumothorax,delayed transition ,infection (e.g., pneumonia, sepsis), nonpul-monary causes (e.g., anemia, congenital heart disease,

musculoskeletal abnormalities of the chest, lesions of the dia-phragm and abdomen, medications, neurologic or metabolicabnormalities, polycythemia, upper airway obstruction), and

persistent pulmonary hypertension of the newborn (2).Chestradiograph can help to differentiate between them. These in-clude primary pulmonary disease, which can be divided into

those that can be treated medically and those requiringsurgery. In general, medical conditions in the newborn causebilateral pulmonary disease, whereas surgical problems areoften unilateral and frequently produce contralateral shift of

the mediastinum. Cardiac disease is an important cause ofrespiratory symptomatology in the neonate, for which ultra-sound (US) is particularly useful. Extrapulmonary lesions are

also important and should be suspected if the chest radiographis normal or only mildly abnormal in the presence of respira-tory distress. Cross-sectional imaging such as computed

tomography (CT) is frequently required for the confirmationof diagnosis, further characterization, and preoperative evalu-ation in the case of surgical lesions (3).

The objective of our study was to assess the value ofmultiplanar and 3D MDCT images in evaluating respiratorydistress in neonates.

2. Patients and methods

2.1. Patients

Within the period between November 2010 and November2011, 1295 newborn were admitted in neonatal intensive care

unit of the Assiut university children hospital with respiratorydistress (cyanosis, tachypnea, retraction, grunting, stridor, orfeeding difficulties).

Clinical evaluation together with laboratory workup, plainchest X-ray, and/or echocardiography (when it was needed)was done. The final diagnosis was confirmed in 1279 cases as

respiratory distress syndrome in 553 cases (42.7%), transienttachypnea of newborn in 435 cases (33.5%), pneumonia & sep-sis in 124 cases (9.5%), meconium aspiration syndrome in 59cases (4.6%), air leak syndromes in 48 cases (3.8%), diaphrag-

matic hernia in 11 cases (0.8%) and extrapulmonary causes in49 cases (3.9%). However, in 16 cases (1.2%) plain X-ray find-ings were suggestive, but it was not conclusive for congenital

surgical pulmonary problems. So they were underwentMDCT.

All patients were receiving supportive care in the form of

incubator care, oxygen therapy, partial or total parental nutri-tion, monitoring of vital signs and blood gas analysis, antibac-terial therapy and assisted ventilation when indicated. For

patients with proved surgical problems, surgical consultationand management were done.

2.2. MDCT examination

Sixteen neonates were scanned using 64-rows multi detectorsCT (Aquillion; Toshiba Corporation, Medical System Com-pany, Tokyo, Japan). MDCT was performed with patients in

the supine position. We commonly used oral chloral hydrateas a sedative drug for those neonates according to practice

guidelines for sedation and analgesia published by Americansociety of anesthesia (4). Due to the faster scanning times pos-sible with MDCT scanners, routine sedation is no longer re-

quired. In the neonate, recent feeding usually providestranquillity.

2.2.1. Technical factors

Multidetector CT parameters: using low kilovoltage and tubecurrent appropriately to reduce the radiation dose: 80–100 kV and approximately 60–90 mAs (following an ALARA

[as low as reasonably achievable] principle) (5). Other technicalparameters are as follows: detector collimation, 64 · 0.5 mm;beam pitches 0.8 and gantry rotation time 0.5 s and image

reconstruction matrixes 512 · 512.Intravenous contrast material: it is needed to assess the vas-

cular anomalies. Neonates have a smaller than 22- gauge can-

nula or central venous line in place, the contrast medium wasadministered by means of manual injection using non-ioniccontrast material (300 mgI/ml). The usual recommended con-trast material dose is 2 mL per kilogram of patient body

weight (up to a dose of 125 mL) (6,7).Oral contrast medium: it was used in suspected cases of dia-

phragmatic hernia in order to opacify the bowel. A 60 mL di-

lute water-soluble iodine based contrast medium was given bynasogastric tube before the examination.

Timing of CT: regarding the postcontrast scan delay, the

scan starts at the end of the injection.Anatomic scan coverage: Scans are usually acquired from

the level of thoracic inlet to the level of the diaphragm. In cer-

tain situations, however, CT scan coverage must be modified.More inferior extension to the level of the renal artery shouldbe considered in evaluating extralobar sequestration becausethe anomalous artery in this situation can arise from the

descending aorta below the level of the diaphragm (8,9).Post processing Techniques: After scanning, the axial

images were transferred to an independent workstation (Vir-

tea, Toshiba) for post processing. Post processing methods:multiplanar reformation or reconstruction (MPR), and 3-Dimensional (3D) imaging including maximum intensity pro-

jection (MIP) and volume rendering (VR) images.

2.2.2. Image analysis

Axial, MPR, MIP, and VR images were evaluated indepen-

dently and retrospectively by two radiologists who reviewedand evaluated all CT studies. The axial images were viewedwith standard lung window settings (e.g., width –1,600

to –1,800 H; level, –450 to –550 H) and standard soft-tissuewindow settings (e.g., width, 400–450 H; level, 40–50 H). Eval-uating MPR in coronal, sagittal, and curved planes. The 3Dreconstructed images were presented in two formats––one with

more opacity to show the vessels and the other with moretransparency to show the airway. The axial CT images wereinterpreted first, followed by the multiplanar images at the

same review session. The 3D volume-rendered images wereinterpreted independently at a later session in depicting thebronchopulmonary and vascular anomalies as following:-

� Pulmonary lesions

� Symmetry of hemithorax

� Decrease CT attenuation� Increase CT attenuation

Table 1 Pattern of MDCT findings in 16 neonates.

Pulmonary Trachea and bronchi Vascular Associated No (%) Radiological diagnosis

Unilateral opacified hemithorax 5/16 (31.25%)

Decrease in volume of

right lung

Small caliber of right

bronchus

Small pulmonary artery Shift of the

mediastinum to the

affected right side

1 Primary Pulmonary

Hypoplasia

Decrease in volume of

left lung

Abrupt tapered left

main bronchus

� Aneurysmal dilata-

tion of the main pul-

monary artery and

osteal stenosis of left

pulmonary artery.

� Right sided aortic

arch with ALSA.

� Compensatory

hyperinflation of the

right lung with

transmediastinal

shift.

� Opacified left lung

1 Primary Pulmonary

Hypoplasia

Decrease in volume of

right lung

Abrupt tapered right

main bronchus

The mediastinum is

displaced to the

Contralateral side.

Presence of contrast

filled bowel loops in the

right hemithorax.

2 Secondary pulmonary

hypoplasia due to

congenital

diaphragmatic hernia-

Bochdalek Type

Total opacified right

hemithorax

NA Ipsilateral mediastinal

shift

1 Atelectasis

Hyper lucent lesions 6/16 (37.5%)

Multiple bilateral air

filled cysts communicate

with each and with the

airway. More than 2 cm

in diameter.

NA Segmental atelectasis of

the right upper lobe.

4 Congenital cystic

adenomatoid

malformation

(CCAM)type I

Unilocular Left upper

lung air filled cyst about

10 cm

NA Contralateral

mediastinal shift

Multilocular large air

filled cyst occupying

almost of the left lower

lung lobe that has thick

wall.

NA Alveolar patches of the

surrounding lung

parenchyma

Air-filled distension of

the upper lobe of the left

lung.

NA Rightward shift of

mediastinum.

1 Congenital lobar

emphysema

Presence of both air and

fluid in the left pleural

space

NA � Partial collapse of

left lung (passive

atelectasis)

� Fixed left intercostal

tube.

1 Left postoperative

hydro-pneumothorax

Different alveolar pattern: 5/16 (31.25%)

Bilateral patchy area of

consolidation

Air bronchogram 4 Pneumonia

Right upper lobe

collapse.

1

NA= No Abnormality

Multidetector computed tomography evaluation in neonatal respiratory distress: Clinical implication 103

� Trachea and bronchial lesions� Abnormal reduced caliber� External compression.

� Vascular lesions� Pulmonary arteries and veins

� Aorta

� Any abnormality of pleura, diaphragm and chest cage.

3. Results

Most of the neonates in this study were suffering from respira-tory distress due to medical causes in whom clinical evaluation

Fig. 1 MDCT images in 15 days male neonate. Axial (a), sagittal (b) and coronal(c) reformatted images demonstrating multiseptated

cystic lesion in both lungs mainly in both the upper lobes. The largest was located in the left side with transmedistinal extension (arrowed)

consistent with congenital cystic adenomatoid malformation type 1 as clearly evident on 3DVR image (d).

104 E.A. Elhamd et al.

together with laboratory work, plain chest X-ray, and/or echo-

cardiography when it was needed, were sufficient and theywere managed accordingly.

Only 16 neonates were included in whom plain chest X-ray

findings were suggestive, and it were not conclusive for con-genital surgical pulmonary problems. Their radiologic diagno-sis is summarized in Table 1.

Hyperlucent lesions are encountered in 6 neonates includ-ing congenital cystic adenomatoid malformation (CCAM),congenital lobar emphysema (CLE) and postoperativehydropneumothorax.

In four neonates presented with CCAM, CT demonstratesmultiple air filled cysts that vary greatly in size and shape. 2–8 cm cysts were scattered in both lung lobes mainly the upper

lobes in one neonate (Fig. 1). In another neonate, CT depicts alarge unilocular air-filled cyst measured 10 cm in maximumdiameter occupying almost all of the right lower lobe and

the posterior segment of the upper lobe with internal septa-tions and it is associated with mass effect as mediastinal shiftto the contralateral side. In the remaining two neonates, a mul-tilocular large air filled cyst occupies almost of the left lower

lung lobe that has a thick wall and it is accompanied with alve-olar patches involving the surrounding lung parenchyma.

One neonate has CLE; CT depicts the hyperinflation of the

left upper lobe with subsequent mass effect upon the adjacentbronchovascular structures (Fig. 2).

One case has left hydro-pneumothorax postoperatively for

the repair of the left sided congenital diaphragmatic hernia(Fig. 3).

Unilateral opacified hemithorax was encountered in 5 neo-

nates who have unilateral small sized lungs due to unilateralhypoplastic lung in two cases and unilateral right atelectasisin one case and congenital diaphragmatic hernia in two cases.

The first case has a small right lung with mediastinal shift to

the affected side and narrow right main bronchus that isclearly seen on MPR and 3D VR images. MPR and 3D imagesfor MDCT angiography revealed hypoplastic right pulmonary

artery (2 mm) with absent right pulmonary veins (Fig. 4).The second case has a small left lung with a narrow left

main bronchus and MDCT angiography revealed dilatation

of the main pulmonary trunk with osteal stenosis of the leftpulmonary artery (2.2 mm) that is smaller than the contralat-eral one and this was clearly evident on MPR and 3D VRimages (Fig. 5).

In another two neonates, opacified right hemithorax withair filled structures occupy the lower lung zone. Instillation

Fig. 2 7 days female neonate. MDCT scan in coronal (a, b) reformatted images in lung window demonstrate hyperinflation of the left

upper lobe with contralateral shift of the mediastium impressive of CLE. Alveolar patches affecting the right lung seen in axial image (c) in

mediastinal window. 3D VR image (d) demonstrates the extent of hyperinflated left upper lobe and area of hypoareation affecting right

lung consistent with pneumonic consolidation.

Multidetector computed tomography evaluation in neonatal respiratory distress: Clinical implication 105

of gastrograffine through the Ryle tube revealed opacifiedintestinal loops herniating into the right hemithorax accompa-nied with herniating liver with subsequent decrease or no aer-

ation of the right lung clearly evident on MPR and 3D VRimages (Fig. 6).

The fifth neonate has a unilateral opacified right hemitho-

rax with ipsilateral mediastinal shift. On follow-up radio-graphs, reareation of the right lung occurred and thus it isdiagnosed as atelecatsis and MDCT helped to exclude

anomalies.Alveolar opacities were seen in five neonates. Four cases

have bilateral patchy areas of consolidation and segmental ate-

lectasis. One case has right upper lobe consolidation (Fig. 7)Regarding the trachea, small caliber of bronchi is encoun-

tered in cases of hypoplasia of the lung.Regarding vascular anomalies, CT angiography in MPR,

maximum intensity projection (MIP) and VR images revealedhypoplastic pulmonary artery in one case (Fig. 4) and ostealstenosis of the left pulmonary artery with dilatation of main

pulmonary artery in one case. The latter one is associated witha right sided aortic arch with an aberrant left subclavian artery

(Fig. 5). Small pulmonary veins are noticed draining the hypo-plastic lung.

Common associations are found including mediastinal

shift, pneumonic alveolar patches and atelectasis.

4. Discussion

The respiratory distress in neonates may be because of a pre-dominantly medical or surgical pathology or may be a medicalcondition superimposed on surgical pathology (10).

MDCT may be useful in confirming the presence of the le-sion, determining the extent of the lesion, and defining associ-ated abnormalities. Reconstructed data from CT examinations

displayed in either 3D or multiplanar formats can be particu-larly helpful in delineating abnormalities of the bronchi andassociated arterial and venous structures (11,12).

In the present prospective study, 16 neonates; whose plainchest radiographs were equivocal; were included and hadundergone MDCT examination for further assessment ofradiographic abnormalities of areation. This is also mentioned

by Donnelly and Frush (13) who stated that in cases with

Fig. 3 25 days male neonate. Contrast enhanced MDCT in axial (a) at upper cuts and sagittal (b) reformate in mediastinal window

revealed normal caliber of the pulmonary trunk with symmertical caliber of main pulmonary areteris and evidence of left pleural effusion

with fixed intercostal tube. Coronal reformate (c) image in lung window demonstrates normal shape and caliber of the trachea and both

bronchi , presence of air in the pleural space and partial aeration of the left lung as clearly evident on VR images (d). Postoperative

hydropneumothorax was the diagnosis.

106 E.A. Elhamd et al.

unclear diagnosis, CT often provides diagnostic informationabout the exact anatomic location of the lesion difficult to

determine on chest radiography.Several acquired and congenital causes of localized lung

radiolucencies are seen in neonates, including acute pulmonary

interstitial emphysema, localized persistent pulmonary emphy-sema, congenital cystic adenomatoid malformation (CCAM),and congenital lobar emphysema (CLE). The radiolucent nat-

ure of these lesions is also distinct from other congenital lungmasses, such as bronchogenic cyst and sequestration that donot typically contain air when encountered during the neonatalperiod (13). In the present study, six neonates had radiolucent

lesions.In this study, we had only one case of CLE with hyperinfla-

tion of the left upper lobe. MDCT images demonstrated a

hyperinflated left upper lobe with attenuating and displacedpulmonary vessels and contralateral mediastinal shift thatwas clearly depicted on reconstructed volume rendering images

of the airways. This is consistent with Ozcelik et al. (14) whostated that CLE is usually present during the neonatal periodand infancy with respiratory distress, especially when there ismarked hyperinflation in the involved lobe and mass effect

on the adjacent lung parenchyma or mediastinum with a lobar

predilection (left upper lobe > right middle lobe > rightupper lobe > lower lobes).

Congenital cystic adenomatoid malformation is resultingfrom disorganized hamartomatous and adenomatoid prolifer-ation of primary bronchioles, which are in communication

with the bronchial tree (15,16). There are three types ofCCAM, which have different radiologic appearances, grosspathologic findings, and histologic findings, as described by

Stocker et al. (17). The most common subtype is a type 1CCAM, in which there is at least one dominant cyst that is lar-ger than 2 cm in size. Type 2 CCAM has numerous small cystsof uniform size measuring 1–10 mm in diameter. Type 3

CCAM, the least common, appears solid at imaging; however,at histologic evaluation, it is characterized by numerous micro-cysts. CCAM demonstrates a variety of imaging appearances

based on the type of CCAM and the presence or absence ofassociated superimposed infection (18). This is consistent withMDCT findings in four cases in the present study as they had

type 1 CCAM. Bilateral multilocular air-filled cysts about2–8 cm occupied most of upper lung lobes in one of them. Inanother case, a large unilateral air-filled cyst with internal sep-tations occupied most of the right lower lobe and posterior

segment of the upper lobe (about 10 cm) causing a mediastinal

Fig. 4 29 days male neonate with primary pulmonary hypoplasia. Contrast-enhanced MDCT scan in axial cut in mediastinal window

(a), coronal reformate in lung window (b) and VR images of MDCT angiography (c, d) demonstrates small sized right pulmonary artery

(red arrowed), small volume of right lung with subsequent raising of the right hemidiaphragm. Absence of right pulmonary veins with

normal left one (blue dashed arrowed).

Multidetector computed tomography evaluation in neonatal respiratory distress: Clinical implication 107

shift to the contralateral side. In the remaining two, unilaterallarge multilocular thick wall air-filled cysts were seen suggest-ing the presence of associated infection.

Taylor et al. (19) reported that after congenital diaphrag-matic hernia (CDH) repair, a large postoperative pneumotho-rax is not uncommon and should not be rapidly evacuated

because of the increased mobility of the neonatal mediastinum.After the resorption of air surrounding the hypoplastic lung,fluid might accumulate in the pleural space. Follow-up chestimaging after surgical repair might be useful. Cross-sectional

imaging can be helpful in cases where the diagnosis is stillnot clear, and to fully elucidate the spectrum of associated ana-tomic defects. CT with multiplanar reconstruction is useful to

elucidate associated lung masses and bronchopulmonary fore-gut malformations. The use of intravenous contrast agent andCT arteriography should be considered for depiction of the

vascular supply of lung lesions. In the present study, left sidedacquired hydropneumothorax secondary to repaired left sidedCDH was depicted in one case who was referred to undergoMDCT pulmonary with intravenous contrast administration

in order to assess the status of the ipsilateral lung and pulmon-ary vasculature according to pediatric surgeon’s opinion in ourinstitute.

The differential diagnosis of respiratory distress in the new-born associated with marked opacification of one side of the

thorax on radiograph includes atelectasis, congenital diaphrag-matic hernia (CDH), congenital cystic adenomatoid malfor-mation (CCAM), pulmonary sequestration, chylothorax,

pulmonary hypoplasia, bronchogenic cyst, and a chest tumor(e.g., neuroblastoma, teratoma, fibrosarcoma) (20). Five caseshad unilateral opacified hemithorax in the present study.

Pulmonary hypoplasia refers to the presence of a bronchusand rudimentary lung, with a decrease in the number and sizeof alveoli, airways, and vessels. CT can show asymmetricallydecreased lung parenchyma with narrowed airways and fewer

branches in the affected hemithorax and herniation with medi-astinal shift of the contralateral lung. Clinically, infants withunilateral lobar pulmonary hypoplasia may have variable pre-

sentations depending on the extent of lung involvement andcomorbidities. Some infants present with severe respiratorydistress in the first few hours of life whereas some may be com-

pletely asymptomatic. However, most cases of pulmonaryhypoplasia are secondary to conditions that limit fetal lunggrowth. Primary pulmonary hypoplasia is rare. It may becaused by an embryologic defect of the lung or vascular tissues

or an in utero vascular accident (21,22). In the present study,unilateral primary hypoplastic lung was encountered in twocases and unilateral secondary hypoplastic lung in two cases.

One of the two cases of primary hypoplastic lung had asmall sized right lung with very severe hypoplasia of the

Fig. 5 30 days old female neonate. axial contrast-enhanced CT in mediastinal window (a, b), coronal MIP (c) and posterior VR images

(d, e) of MDCT angiography revealed osteal stenosis of the left pulmonary artery(arrowhead) and right sided aortic arch with

ALSA(dashed arrowed) with main and right pulmonary arteries are massively dilated and small volume of the left lung with subsequent

raising of the left hemidiaphragm. Small left pulmonary veins (black arrowed). 3D VR image (d) demonstrates small caliber of the left

main bronchus.

108 E.A. Elhamd et al.

correspondent pulmonary artery. The second case had hypo-plasia of the left lung with severe osteal stenosis of the left pul-monary artery that arose from the main pulmonary artery.This second case was also associated with congenital heart dis-

ease (ventricular septal defect), aneurysmal dilation of mainpulmonary artery and right pulmonary artery and right sidedaortic arch with aberrant left subclavian artery (ALSA) with

no associated complete vascular ring causing pressure symp-toms upon the trachea or esophagus. This is consistent withTurkvatan et al. (23) who reported this anomaly rarely to pro-

duce symptoms and is usually an incidental radiological find-ing and a right arch with an ALSA rarely forms a completevascular ring.

MDCT barely depicted a small hilum and small pulmonary

veins in both primary hypoplastic lung cases. This is consistentwith Apostolopoulou et al. (24) and Oguz et al. (25) studieswho stated that contrast-enhanced CT of the chest produces

an anatomic definition of the pulmonary arteries with consis-

tent quality. An advantage of CT over angiography is thatthe former allows concomitant evaluation of the bronchial treeand lung parenchyma and the major vascular structures. Thecomplex curving anatomy of the pulmonary artery is well dem-

onstrated by MDCT angiography using multiplanar and vol-ume-rendered images. Thus, MDCT is the preferable methodfor studying pulmonary aplasia and hypoplasia.

Secondary pulmonary hypoplasia was found in two neo-nates due to right sided congenital Bochdaleck hernia and sub-sequently reduced size of the right lung. As Ryan (26) who

reported secondary pulmonary hypoplasia is an important fea-ture of congenital diaphragmatic hernia and of oligohydram-nios, such as the Potter sequence. The difficulty indiagnosing these two cases on radiograph was because the

characteristic radiologic appearance of diaphragmatic herniawas unclear. Swischuk (27) and Mandell (28) stated that Boch-dalek hernias are more common on the left, while Morgagni

hernias occur mostly on the right. If herniation occurs on

Fig. 6 2 days male neonate. axial and sagittal reformate in mediastinal window (a, b), coronal reformate in lung window (c) and VR

images (d) of MDCT chest demonstrate dense right hemithorax with upward raise of liver (arrowed) and air-filled bowel loops seen in the

right hemithorax with secondary right hypoplastic lung.

Multidetector computed tomography evaluation in neonatal respiratory distress: Clinical implication 109

the right side, the bowel and liver or liver alone may fill theright hemithorax represented as dense opacity in the lower

right hemithorax. Thus CCAM, particularly when it is locatedin the lower lobes, can be confused with congenital diaphrag-matic hernia. In this situation, CT with coronal and sagittalreconstructions can aid in evaluating the diaphragm thus

enabling the radiologist to distinguish CCAM from congenitaldiaphragmatic hernia (29).

The fifth case had a marked right hemithorax opacification

on chest radiography. On follow-up radiographs, neonatalatelectasis was diagnosed and congenital anomalies could beexcluded on MDCT.

Five cases in this study were referred to MDCT with pneu-monia to exclude underlying congenital anomalies. The mostcommon radiographic manifestation of neonatal pneumoniais a bilateral coarse pattern of perihilar reticular densities

which may also involve scattered areas of air space disease.Isolated lobar pneumonia is uncommon in this age grouplikely related both to the aspirated route of entry as well as

to the inability of the neonate to control infection locally(30). In the present study, MDCT depicted segmental atelecta-sis and alveolar opacities in five neonates. Four cases had bilat-

eral patchy area of consolidation without underling congenitalanomalies. One case had right upper lobar consolidation whowas suspected to have tracheo-esophageal fistula (TOF). The

presence of TOF could be excluded on reconstructed multipla-nar reformate and volume rendering images.

4.1. Limitations of MDCT

The main disadvantage of MDCT is radiation exposure, a fac-tor to be considered particularly in regard to children. Eventhough, to our knowledge, there are no large-scale epidemiol-

ogic studies of the cancer risks associated with CT, consciouseffort should be taken to keep the radiation exposure as lowas possible during scanning (31,32). Thus we use the lowest

possible milliamperage (mA) and kilovoltage (kV). Secondly,we agree with Calder and Owens (33) who stated that auto-mated bolus tracking is problematic in neonates, as drawinga region of interest correctly is difficult in these very small

patients.

5. Conclusion

Although a few number of cases were referred to MDCT inour institution but we could state that MDCT was problemsolving in complicated cases in whom the simpler tests was

inconclusive .We found that MDCT was useful in confirmingthe presence of the lesion, determining the extent of the lesion,and defining associated abnormalities in all our cases. Recon-

structed data from MDCT examinations displayed in either3D or multiplanar formats can be particularly helpful in delin-eating the abnormalities of the bronchi and associated arterial

and venous structures and was able to differentiate 1ry and 2ry

Fig. 7 7 days male neonate. Axial cuts and coronal reformate in lung window (a–c) and VR images (d) of MDCT chest demonstrate

consolidation-collapse of the right upper lung and left lower lung lobes in a neonate had choking on feeding with suspicion of having

tracheo-oesphageal fistula (TOF). Axial, MPR and VR images confirm the absence of TOF.

110 E.A. Elhamd et al.

cases of hypoplasia. Post- processing is essential to fully clarifythe relationship of vascular structures to airways. Multiplanarreformats in axial, coronal and sagittal are an important first

step in which the problem of superimposition of densities inthe CXR is markedly reduced, and the true distribution ofthe disease becomes apparent. Maximal intensity projections

(MIPS) in thin and thick sections can help to accentuate vas-cular structures, but may obscure the airways. Volume ren-dered (VR) images were very useful to demonstrate overallvascular anatomy and detect associated vascular anomalies.

The airways were easily reconstructed with VR images whichdemonstrated the narrowed and congenitally absent bronchi.Lastly, MDCT techniques have revolutionized the imaging

of bronchopulmonary, vascular and tracheobronchialanomalies.

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