VASCULAR RINGS A CASE - BASED REVIEW

Beverley Newman, BSc. MB.Bch. FACR Professor of Radiology

Stanford University and Lucile Packard Children’s Hospital

Q1,2,3

Frontal chest radiographs on three different individuals. For each case suggest the most likely diagnosis. a. No ring or sling b. Vascular ring very likely c. Vascular ring unlikely d. Pulmonary sling very likely e. Pulmonary sling unlikely

Case 1: 16month girl with respiratory distress

Case 2: 16month girl with respiratory distress

Case 3: 2.5 month girl with respiratory distress

Q4,5,6

Additional lateral chest radiographs on the same three children. For each case suggest the most likely diagnosis. a. No ring or sling b. Vascular ring very likely c. Vascular ring unlikely d. Pulmonary sling very likely e. Pulmonary sling unlikely

Case 1:16month girl with respiratory distress

Case 2: 16month girl with respiratory distress

Case 3: 2.5 month girl with respiratory distress

Q7,8,9

Contrast esophagrams on the same three children. For each case suggest the most likely diagnosis. a. No ring or sling b. Vascular ring very likely c. Vascular ring unlikely d. Pulmonary sling very likely e. Pulmonary sling unlikely

Case1: 16month girl with respiratory distress

Case 2: 16month girl with respiratory distress

Case 3: 2.5 month girl with respiratory distress

Q10,11,12

• CT axial images on the 3 cases. For each case suggest the most likely diagnosis.

a. No ring or sling b. Vascular ring very likely c. Vascular ring unlikely d. Pulmonary sling very likely e. Pulmonary sling unlikely

Case1: 16month girl with respiratory distress

Case 2: 16month girl with respiratory distress

Case 3: 2.5 month girl with respiratory distress

Chest Radiographic Findings Suggestive of a Vascular Ring

• Right Aortic arch

• Descending Aorta on opposite side of arch

• Anterior bowing of trachea (lateral view)

6 month old with recurrent respiratory infections

Vascular Ring ESOPHAGRAM

• Not necessary if plain film suggests ring • Confirms likely presence of ring • May suggest type but not definitive

Imaging Vascular Rings CT Angiography

• Fast - decreased need for sedation • .6mm-1mm axial spiral • Timed/triggered dynamic IV contrast (2-3cc/Kg) • 2 and 3-D reconstruction • Pay attention to parameters and radiation dose • Lower kVp (80 -100) • Automodulation of mAs (ref mAs 150) • Breast shield in girls

Imaging Vascular Rings MR Imaging/Angiography

• Multiplanar capability/many sequence options.

• Need specific sequences to optimally evaluate airway

• Timed/triggered dynamic IV contrast for MRA • 2 and 3-D reconstruction of images • No ionizing radiation • Long study/sedation often required

Vascular Ring – combination of vascular/ ligamentous structures encircling the airway

• COMMON – Double Aortic Arch – Right arch, aberrant left subclavian artery + ductus

• UNCOMMON - Left arch, aberrant right subclavian artery + ductus - Right or left circumflex aorta and ductus �� aberrant subclavian artery

- Mirror image right arch + ductus

Imaging Vascular Rings KEY FEATURES

• Arch location

• Branching of aorta

• Compression of airway

• Diverticulum of Kommerel

• Descending aorta

ANTERIOR

POSTERIOR

AA

DA

AA

DA

DOUBLE AORTIC ARCH DOUBLE AO ARCH WITH ATRETIC LEFT SEGMENT

C

S

C

S

DOUBLE AORTIC ARCH

4 symmetric vessels

Bilateral Arches

Ipsilateral carotid and subclavian Branches

Compressed trachea

C

S S

c

DOUBLE AORTIC ARCH

Compressed airway

Descending aorta on left

R R L L

ANTERIOR AA

DA

RIGHT ARCH ABERRANT LEFT SUBCLAVIAN ARTERY

DK

T

E

DAo

AAo

2.5yo RAA ABERRANT LSCA BRANCH, Mild tracheal Compression, Diverticulum, Lt descending AO

LAA ABERRANT RSCA PLUS DIVERTICULUM

LAA ARSCA BRANCH Mild Tracheal Compression Diverticulum behind trachea ( prior TEF repair) Lt SVC

ANTERIOR AA

DA

AA

DA

A

LT INNOM

MIRROR IMAGE RIGHT ARCH RING

Mirror image right Arch Branching

Mild tracheal Compression

Diverticulum

Right descending aorta In

In

Mirror image Rt Arch Branching

Mild tracheal Compression

Diverticulum

Circumflex aorta descending

on left

Left Pulmonary Artery Sling

• Left pulmonary artery arises from RPA • Courses posteriorly between the trachea and

esophagus

Type I PA Sling • Higher level of sling

• N bronchial branching or tracheal bronchus

• Associated compression/malacia (trachea/RMSB)

15yo girl with known VSD

15yo girl with known VSD

Type 1 PA sling

LPA Sling – Chest Radiographic Findings

• May be normal

• Mass posterior to trachea on lateral view

• Unilateral hyperinflation (Type I)

• Bilateral hyperinflation or small right lung (Type II). Low T carina

Type II PA Sling ( Ring/Sling complex) • Low position of PA sling • Horizontal low carina • Abnormal airway branching • Associated long segment airway stenosis • May be right lung hypoplasia/agenesis

5week old male with severe stridor

Newborn male with severe respiratory distress

Newborn male with severe respiratory distress

1

2

3

Type IIA LPAS

49 YO F PREVIOUS TOF REPAIR RIGHT DIAPHRAGMATIC PARALYSIS DECREASED EXERCISE

TOLERANCE Previously unrecognized Type IIA PA sling and tracheal stenosis

Tracheal stenosis

LPA Sling Pre &Post

10 day old with tachypnea

10 day old with tachypnea

5 month old male with persistent respiratory symptoms

SUMMARY

• Vascular rings and slings are often first suspected on the basis of plain chest radiographs

• There is a wide spectrum of lesions and radiographic appearances

• Cross-sectional angiography provides the detailed anatomy needed for operative planning of vascular lesions compressing the airway

• Carefully evaluate and report vascular & airway appearance and relationships

• Multiple planes, 2D and 3D reconstructions are useful in understanding and communicating the important anatomy

References Vascular Ring/Pulmonary Artery Sling

1. Berdon WE. Rings, slings, and other things: Vascular compression of the infant trachea updated from the mid-century to the millennium – the legacy of Robert E. Gross, MD, and Edward B.D. Neuhauser, MD. Radiology 2000; 216:624-632

2. Chan, MS, Chu WC, Cheung KL, Arifi AA, Lam WW. Angiography and dynamic airway evaluation with MDCT in the diagnosis of double aortic arch associated with tracheomalacia. AJR 2005; 185(5): 1248-1251

3. Dodge-Khatami A, Tulevski II, Hitchcock JF, et al. Vascular rings and pulmonary arterial sling: from respiratory collapse to surgical cure, with emphasis on judicious imaging in the hi-tech era. Cardiol Young 2002; 12:96-104.

4. Eichhorn J, Fink C, Delorme S, et al. Rings, slings and other vascular abnormalities. Ultra fast computed tomography and magnetic resonance angiography in pediatric cardiology. Z Kardiol 2004; 93:201-208

References Vascular Rings (cont.)

5. Hernanz-Schulman M. Vascular rings: a practical approach to imaging diagnosis. Pediatric Radiology 2005; 35:961-979

6. Mahboubi S, Meyer JS, Hubbard AM, et al. Magnetic resonance imaging of airway obstruction resulting from vascular anomalies. International J of Pediatric Otorhinolaryngology 1994; 28:111-123. 7. Dillman JR, Attili AK, Agarwal PP, Dorfman AL, Hernandez RJ, Strouse PJ. Common and uncommon vascular rings and slings: a multi-modality review Pediatr Radiol. 2011 Nov;41(11):1440-54 8. Newman B, Cho YA. Left Pulmonary Artery Sling-Anatomy and Imaging. Semin Ultrasound CT MR 2010; 31:158-170.