Eur J Pediatr (1992) 151 : 710-712
European Journal of
9 Springer-Verlag 1992
Diagnosis of intralobar lung sequestration by colour-coded Doppler sonography K. H. Deeg 1, M. Hofbeck 2, and H. Singer 2 1Paediatric Clinic of Bamberg, Bugerstrasse 80, W-8600 Bamberg, Federal Republic of Germany 2paediatric Clinic of the University of Erlangen-Nttrnberg Received February 9, 1991 / Accepted in revised form January 28, 1992
Abstract. I n t r a l o b a r lung sequestration in a 5 - m o n t h - o l d dyspnoeic infant was diagnosed by c o l o u r - c o d e d D o p pler s o n o g r a p h y (CDS). G r e y scale imaging showed an echogenic mass adjacent to the right h e m i d i a p h r a g m . C D S d e m o n s t r a t e d an a b n o r m a l arterial b l o o d supply via a vessel originating f r o m the descending aorta at the level of the diaphragm.
Key words: Intralobar lung sequestration - Infants Diagnosis by c o l o u r - c o d e d D o p p l e r s o n o g r a p h y
Introduction P u l m o n a r y sequestration is a rare congenital m a l f o r m a tion in which a part of the developing lung does not have a n o r m a l bronchial c o m m u n i c a t i o n or p u l m o n a r y vascular supply. A constant feature of this abnormality is the a n o m a l o u s systemic b l o o d supply f r o m the thoracic or abdominal aorta. Diagnosis of p u l m o n a r y sequestration relies u p o n the identification of the pathological arterial vessel by arteriography, c o m p u t e d t o m o g r a p h y , magnetic resonance imaging and ultrasound. W e report the diagnosis of intralobar p u l m o n a r y sequestration by c o l o u r - c o d e d D o p pler s o n o g r a p h y (CDS).
child was noted to be dyspnoeic. At the age of 5 months she was admitted to the Paediatric Clinic with persistent dyspnoea. Physical examination showed a 5-month-old female infant in good general condition. The child was moderately dyspnoeic and showed intercostal and subcostal retractions. On auscultation the lungs were clear. No other abnormalities could be found. Chest X-ray film demonstrated a normal heart size with an atelectasis of the right basal paravertebral lung segments. Bronchoscopy revealed an external compression of the right lower lobe. Sonography showed an echogenic mass adjacent to the fight hemidiaphragm. CDS revealed an abnormal arterial vessel originating from the lower thoracic aorta close to the diaphragm (Fig. la). Pulsed Doppler sonography confirmed an arterial flow pattern in this vessel which could be traced to the mediobasal segments of the fight lung (Fig. lb, c). Colour flow imaging showed multiple internal vessels (Fig. lc). Pulsed Doppler sonography revealed arterial and venous flow patterns. No draining vein below the diaphragm could be shown suggesting intralobar lung sequestration. Pulmonary sequestration was confirmed by cardiac catheterization and angiography. Left ventricular angiography demonstrated an anomalous arterial vessel originating from the lower thoracic aorta which supplied basal segments of the right lung (Fig. 2). The venous drainage of the sequestration was a right pulmonary vein. Resection of the sequestrated lung segments and ligation of the supplying artery was performed via a right thoracotomy. There was no communication of the sequestrated segment with the normal bronchial system. The postoperative course was uneventful. The child is now in good health without any breathing problems.
Discussion Case report The patient was the second child of healthy parents. Pregnancy was complicated by premature contractions starting in the 28th week of gestation. The infant was spontaneously delivered in the 36th week with a birth weight of 2770 g. At the age of 2 months the Correspondence to: K. H. Deeg
CDS = colour-coded Doppler sonography; ELS = extralobar sequestration; ILS = intralobar sequestration
In lung sequestration a mass of lung tissue is separated f r o m the bronchial tree and f r o m the p u l m o n a r y arterial supply. T h e b l o o d supply to the sequestration is derived f r o m the systemic arteries. T h e r e are two types of pulm o n a r y sequestration: intralobar (ILS) and extralobar sequestration (ELS). In ILS the sequestrated segment lies within the n o r m a l lung pleura, while in E L S it is outside the n o r m a l lung pleura. B o t h types of lung sequestration occur p r e d o m i n a t e l y in the lower lobes adjacent to the diaphragm. U l t r a s o u n d p r o v e d useful in evaluating chest masses in children [6, 8]. Sequestration should be considered if
Fig.2. Left ventricular angiography shows a pathological artery originating from the descending aorta in the region of the diaphragm
a basilar uniformly hyperechoic mass containing vessels is seen [2, 5, 7-9]. Although the sequestrated pulmonary lobe may contain one or more cysts [8, 9], the ultrasound appearance of pulmonary sequestration shows predominantly a solid appearance . Other hyperechoic chest masses may include cystic adenomatoid malformation, diaphragmatic hernia, bronchogenic cyst, mediastinal teratoma, pneumonia, atelectasis and sequestration [46, 8]. The diagnosis of sequestration can be made if a systemic artery feeding the echogenic mass can be shown either by angiography [2, 8] or by Doppler sonography [5, 91. Several reports have even demonstrated prenatal sonographic diagnosis of pulmonary sequestration [1, 3,
Fig. 1. a CDS of the abnormal arterial blood supply (asterix) originating from the descending aorta (AO) to an echogenic mass adjacent to the diaphragm (coronal scan - upper abdomen). The flow in the aorta is displayed red, whereas the flow in the abnormal artery is displayed blue as it streams away from the transducer. b Duplex Doppler sonography of the flow pattern in the abnormal vessel. The upper part of the picture shows the localization of the sample volume of the pulsed Doppler device within the abnormal vessel. The lower part of the picture shows a pulsatile flow pattern characteristic of an artery. The flow profile is displayed below the baseline as the flow is directed away from the transducer, e Colour flow imaging of the echogenic mass adjacent to the right hemidiaphragm shows multiple internal vessels
Using CDS the feeding arteries and draining veins can be displayed simultaneously within the grey scale image. Additionally, the internal vessels of the sequestration can be shown. Using simultaneous Duplex Doppler sonography a pulsatile flow can be found in the feeding artery whereas the draining vein shows a continuous flow of low velocity. Diagnosis of lung sequestration requires the demonstration of the systemic arterial supply to the sequestrated lung segment. If the feeding arteries originate from the abdominal aorta, the demonstration of the systemic arterial blood supply should always be possible by CDS. Difficulties may arise if the feeding arteries arise from the thoracic aorta above the diaphragm or from an intercostal artery. To distinguish between ILS and ELS the venous drainage pattern must be defined . In ILS the venous drainage is through the pulmonary veins, whereas in ELS the veins drain into the systemic veins, often the hemiazygos or portal system . The venous drainage in ELS into the portal or hemiazygos vein should always be possible by CDS. The demonstration of venous drainage in ILS may be very difficult in the individual case, however, dis-
712 tinction b e t w e e n the two types of sequestration is rarely of clinical importance.
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