Medical Central Resource

Meckel's diverticulum

Raiken, David

2/7/97

Presentation

27 year old male with large GI bleed.

Imaging Technique

Nuclear Medicine

Imaging Findings

An area of focal uptake appears in the Right Lower Quadrant of the Abdomen. This focus appears at the same time as gastric activity, and it's intensity increases in parallel with gastric activity.

Diagnosis

Meckel's diverticulum

Discussion

Tc-99m pertechnetate localizes to ectopic gastic mucosa when it is taken up by mucin secreting cells. A Meckel's Diverticulum is the most common congenital anomaly in the GI tract. By the "Rule of Twos": It affects 2% of the population; it is located within 2 feet of the terminal ileum; the majority of patients are under the age of 2 years old (60%); and the usual size is 2 cm, although they can be larger. Gastric mucosa is present overall in only 10%-30% of patients; in 60% of patients who are symptomatic; and in 98% of those who bleed.
Fasting needs to be started 3-4hours prior to scan and urinary voiding needs to be done before, during and after the study as a full stomach or urinary bladder may obscure the diverticulum. Increased activity is seen in the RLQ within 5-10 minutes and increases as gastric uptake increases. Lateral and oblique images may help. Pharmacologic augmentation can be performed with
  1. pentagastrin - increases rapidity, duration and intensity of pertechnetate uptake. Mechanism ? increased acid production leading to secondary activity of mucin cells.
  2. glucoagon - antiperistaltic
  3. cimetidine - inhibits release of pertechnetate from gastic mucosa.

A Meckel's Scan is useful with GI duplications, retained gastic antrum after Bilroth II procedure, and in Barrett's esophagus. False positives results can be seen with vascular malformations, small bowel obstruction, urinary tract abnormalities/anamolies, and hyperemia secondary to inflammation.

Submitted by: David Raiken,Capt,USAF,MC,Wilford Hall Medical Center
Reviewed by: John Morrison,Col,USAF,MC,Wilford Hall Medical Center

References

Thrall, James H.; Ziessman, Harvey A.NUCLEAR MEDICINE:THE REQUISITES.Mosby;St. Louis. 1995; 248-52.