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

CN VII, Facial Nerve, VII, 7th Cranial Nerve

(12) A 45-year old woman develops a tumor of the left parotid gland. On physical exam, what sign might you see in this patient due to compression of a cranial nerve in the region of the tumor? 

Explanation

Correct Answer: 
Drooping of the mouth on the left
Take-Home Message: 
The facial nerve, which is the major motor nerve to the muscles of facial expression, passes through the parotid gland to reach the face.
Explanation of Correct Answer: 
The facial nerve, cranial nerve 7, exits the skull via the internal auditory canal in company with the 8th cranial nerve (acoustic or auditory). In the petrous bone, it has a tortuous course, traveling first in the facial canal and finally exiting the skull via the stylomastoid foramen, just medial to the mastoid process. After this point, it travels forward within the substance of the parotid gland, where it divides into its terminal branches that are distributed to all of the muscles of facial expression. Because of this complex course, the facial nerve is at risk of damage by any process that involves the parotid gland, including tumors as well as surgery on the parotid.
Explanation of Incorrect Answers: 
The masseter muscle, a muscle of mastication, is supplied by the trigeminal nerve, not the facial nerve Taste to the posterior 1/3 of the tongue is supplied by the glossopharyngeal nerve, not the facial nerve Motor fibers to the parotid gland are supplied by parasympathetic fibers in the glossopharyngeal nerve, not the facial nerve
Clinical Pearls: 
Bell’s palsy is due to loss of function of the facial nerve, leading to facial drooping. It is idiopathic, but may be due to viral infection or Lyme disease.
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://library.med.utah.edu/neurologicexam/html/cranialnerve_anatomy.html#09 
http://www.cancer.org/docroot/CRI/content/CRI_2_4_1X_What_is_salivary_gland_cancer_54.asp?sitearea 

Diaphragm, phrenic nerve

: 

labeled CT: 

Explanation

The structure outlined in red is the diaphragm, or the thoracic diaphragm (to distinguish it from other diaphragms, such as the urogenital or pelvic diaphragm).  It is the primary muscle of respiration, pulling the lungs downward like a piston when it contracts, leading to inspiration.  The innervation of the diaphragm is primarily the phrenic nerve, which arises from C3, C4 and C5, passing along the lateral margins of the mediastinum to reach the lower chest.  Some innervation is also supplied from intercostal nerves to the peripheral portions of the diaphragm.

brachiocephalic artery

labeled CT: 

unlabeled CT:

Explanation

The labeled CT images show the course of the ascending aorta, aortic arch, and descending aorta, along with the three major branches that arise from the aortic arch.  The branch outlined in blue is the brachiocephalic artery.

The aorta is outlined in red, the left common carotid artery in purple, and the left subclavian artery in yellow. The only branches that arise from the ascending aorta are the coronary arteries.  The descending aorta gives off the bronchial arteries, the esophageal arteries, mediastinal arteries and the posterior intercostal arteries.  After the thoracic aorta enters the abdomen via the aortic hiatus of the diaphragm, it becomes the abdominal aorta.  Two of the midline branches of the upper abdominal aorta are also labeled:  the celiac artery (in green) and the superior mesenteric (in dark blue).

Image A shows an abnormality of the branches off the aorta:

Image B shows the aortic arch and its branches outlined:

The aorta is outlined in red.  The first branch, the brachiocephalic artery, is shown in green.  There is a rounded outpouching near the origin of this vessel that protrudes from the anterior side of the vessel.  A contour abnormality of this type is called a saccular aneurysm, and in this patient this abnormality was visible on the lateral chest radiograph, simulating an anterior mediastinal mass.  The normal left common carotid artery is shown in yellow and the normal left subclavian artery is shown in blue.

labeled CT: 

unlabeled CT: 

Explanation

The labeled CT shows the main pulmonary artery and its two branches, the right and left pulmonary arteries outlined in blue.

Figure A shows an abnormality of the right pulmonary artery.

The main, right and left pulmonary arteries are outlined in blue. There is a large right mediastinal mass of relatively low attenuation (a liposarcoma) that is compressing the right pulmonary artery.

Figure B shows a different abnormality of the pulmonary artery.

In this case, a small cell lung carcinoma (outlined in red) has directly invaded the right pulmonary artery  (outlined in purple), producing complete obstruction of flow to the right lung.  Only bronchial artery branches remain patent to supply blood to the right lung tissues.

Clavicles

eled CT: 

labeled CT: 

Explanation

The right and left clavicles are outlined in blue.  They are positioned obliquely for a chest CT scan because the patient's arms are raised overhead.  This rotates the scapulae and lifts the lateral ends of the clavicles from the usual resting position. The patient's arms are overhead for this study because it decreases artifacts in the upper portion of the chest due to excessive bone.  If patients are scanned with their arms at their sides, the course of the beam in the coronal plane must pass through the humeri, scapulae, and spine, and this produces streak artifact.

Pulmonary Artery or Pulmonary Trunk

eled CT: 

labeled CT: 

Explanation

The right and left clavicles are outlined in blue.  They are positioned obliquely for a chest CT scan because the patient's arms are raised overhead.  This rotates the scapulae and lifts the lateral ends of the clavicles from the usual resting position. The patient's arms are overhead for this study because it decreases artifacts in the upper portion of the chest due to excessive bone.  If patients are scanned with their arms at their sides, the course of the beam in the coronal plane must pass through the humeri, scapulae, and spine, and this produces streak artifact.

Explanation

The labeled CT shows the main pulmonary artery and its two branches, the right and left pulmonary arteries outlined in blue.

Figure A shows an abnormality of the right pulmonary artery.

The main, right and left pulmonary arteries are outlined in blue. There is a large right mediastinal mass of relatively low attenuation (a liposarcoma) that is compressing the right pulmonary artery.

Figure B shows a different abnormality of the pulmonary artery.

In this case, a small cell lung carcinoma (outlined in red) has directly invaded the right pulmonary artery  (outlined in purple), producing complete obstruction of flow to the right lung.  Only bronchial artery branches remain patent to supply blood to the right lung tissues.

left subclavian artery

abeled CT: 

labeled CT: 

What is outlined in yellow on the labeled CT images? Be specific!

Explanation

The labeled CT images show the course of the ascending aorta, aortic arch, and descending aorta, along with the three major branches that arise from the aortic arch.  The branch outlined in yellow is the left subclavian artery.

The aorta is outlined in red, the left common carotid artery in purple, and the left subclavian artery in yellow. The only branches that arise from the ascending aorta are the coronary arteries.  The descending aorta gives off the bronchial arteries, the esophageal arteries, mediastinal arteries and the posterior intercostal arteries.  After the thoracic aorta enters the abdomen via the aortic hiatus of the diaphragm, it becomes the abdominal aorta.  Two of the midline branches of the upper abdominal aorta are also labeled:  the celiac artery (in green) and the superior mesenteric (in dark blue).

Image A shows an anomaly of the aortic branches:

Image B shows labels on the structures in these CT images.

The aorta is outlined in red.  The right subclavian artery has an anomalous origin, coming off as the last branch of the aortic arch and passing posterior to the trachea and esophagus.  This is called an aberrant right subclavian artery.  The aberrant vessel is shown in pink.  The right common carotid artery (there is no brachiocephalic artery in this case, since the right common carotid artery and right subclavian artery do not arise from a common trunnk) is shown in blue, the left common carotid artery in yellow and the left subclavian artery in green.