Pneumatosis Intestinalis

 

Rigler Triad

Gas in the biliary tree
Small bowel dilatation
Ectopic gallstone
  

Pneumobilia, gas in the biliary tree

Communication between the bowel and the biliary tree
Surgery and Duodenal ulcers are the most common causes
Fistula caused by gall stones
    

Rigler Sign

See the outline of the small and large bowel outlines - outlined by intraperitonial gas
Free air - Best seen in the right upper quadrant

Rigler Sign

Barium enema

Barium enema

Sigmoidoscopy before a barium enema remains good practice, but not essential

Bowel preparation:

Browns dietary restriction, overhydration, and osmotic purgation

Double contrast barium enema (DCBE)

3 stages

1.     Filling with barium

a.     IV smooth muscle relexant – 20mg Buscopan or 0.5 – 1mg of glucagon

b.     Barium introduced while patient is prone until the barium column enters the transverse colon

2.    Gas insufflation

a.     Ideally CO₂

b.     Bring the patient into the head up position and drain the barium

c.     Rotate the patient to the right side – to open the hepatic flexure- the hepatic flexure is dependent and fills with barium

d.     The head of the table is then tilted to trap the barium in the ascending colon, and the patient is prone to fill the dependent cecum

3.    Radiography

Interpretation:

1.     Surface pattern recognition: Barium interacts with the mucosa to form a 0.2mm coating adherent to the mucosa – thickness is usually smooth and even.

a.     Normal varients

                                          i.    Innominate groove pattern – fine transverse grooves are just visible 

                                         ii.    Lymphoid nodular hyperplasia.

1.     Follicles are 1-3mm in diameter, submucosal – with minimal elevation and have no meniscus

2.    Prominent lymphoid follicles in a child. Note the umbilication of some follicles

b.     Early Crohns disease

                                          i.    Lymphoid hyperplasia has been reported

                                         ii.     Viral and bacterial infections

c.     Familial adenomatous polyposis

d.   Depressed markings –

                               i.   erosion-which creates a granular pattern

                              ii.   Ulcers are deeper and filled with barium –so a small projection is seen tangentially outside the mucosal line

e.    Elevated markings

2.    Lines

a.     Barium coating is 0.2mm thick – outling the luminal edge

b.     Normal lines: haustra and flexures

c.     Abnormal lines: diverticula, along the stalks of pedunculated polyps, elevated lesions  

3.    Barium pools

a.     Ring shadow is due to: Polyp, Diverticulum, Faecal residue, Air bubble, Food particle, or Oil droplet

                                          i.    Polyps form a Hat Sign – Hat sign in an 8mm polyp formed from a meniscus around its base with a thin coating of barium over the surface of the polyp

Causes of error:

1.     Perceptive, technical or both

2.    Double reading

Occlusion of the right coronary artery is most likely to produce ischemia in which of the following portions of the heart?

Explanation

Correct Answer: 
SA node
Take-Home Message: 
The artery to the SA node (arrow 1, below) is a branch of the right coronary artery.
Explanation of Correct Answer: 
The two coronary arteries, right and left, usually supply defined territories of the heart. The right coronary generally has a smaller area of supply than the left although there is some variation in this. The right coronary arises from the right sinus of Valsalva, just superior to the right cusp of the aortic valve and travels around the right side of the heart in the atrio-ventricular groove. As it passes by the right atrium, it gives a small branch that penetrates to supply the SA node. Another branch supplies the AV node. The artery then usually continues around to the inferior surface of the heart to supply the posterior portion of the interventricular septum.
Explanation of Incorrect Answers: 
In over 70% of patients, the cardiac apex is supplied by the left anterior descending coronary artery, a branch of the left coronary artery.
The circumflex coronary artery, a branch of the left coronary artery, generally gives branches that supply the left cardiac border (left marginal arteries).
The anterior interventricular septum is virtually always supplied by the left anterior descending coronary artery, which is a branch of the left coronary artery
Clinical Pearls: 
Since the right coronary artery supplies both the sinoatrial (SA) and atrioventricular (AV) nodes, myocardial infarction due to right coronary artery occlusion can be associated with dangerous cardiac arrhythmias.
For more information on this topic, please click on the following link(s): 
(While these web sources have been vetted by our content experts, please use them with caution --- the peer-reviewed literature should be the ultimate source of medical information.) 
http://www.texasheartinstitute.org/HIC/Anatomy/conduct.cfm 
http://www.texasheartinstitute.org/HIC/Anatomy/coroanat.cfm 
http://www.med.yale.edu/intmed/cardio/imaging/anatomy/coronary_territories/index.html