Meckel's Case 2 Answers

1) Is there any evidence of a Meckel's diverticulum?

Yes, there is a small rounded focus of raised uptake just to the right of the aortic bifurcation.

2) What are the classic appearances of a Meckel's diverticulum on pertechnetate scintigraphy (true positive)?

True Positive Meckel's scan consists of a small, round focal area of increased tracer accumulation usually seen in the right lower quadrant of the abdomen that appears concomitantly with stomach activity and increases in intensity throughout subsequent imaging. It is constant - it doesn't move, increase in size or decrease in intensity.

The sensitivity of the scan varies from 75-100%; specificity of more than 80% has been reported in several studies. This scan provides 95% accuracy for detection of gastric mucosa.

3) What can cause similar appearances (i.e. false positive)?

False positive studies occur in up to 15% of patients and can be caused by active GI bleeding (DU, IBD, appendicitis, laxative abuse), hyperaemia of the bowel (obstruction, intussusception, ulceration, inflammation), menstruation, vascular masses (AVMs, haemangiomas, aneurysms, some tumours), urinary tract structures (hydronephrosis, renal ectopia, bladder diverticulae) or ectopic gastric mucosa (duplication cysts, enteric duplication and Barrett’s oesophagus)

4) Why can these scans be falsely negative?

False-negative results occur in up to 25%. False-negative results can occur when ectopic gastric mucosa is very slight or absent or if necrosis has occurred.

Most of those involved with imaging side of suspected cases of MD may be paranoid and worry about false negatives as all their scintigrams look normal. MD is one of the known great mimics and difficult to diagnose clinically, particularly in children. Therefore most departments end up scanning a whole load of adult patients without MD, depending on the jitteriness of the local surgeons.

5) Why is this patient unusual?

He is unusual purely due to his age. Although the vast majority of those with a MD present before the age of 10, patients as old as 85 years old can present with complications of a MD. There is no difference in incidence between the sexes but several series have reported that males are more prone to suffering complications relating to a MD.

In those less than 5 years old, pain and lower GI bleeding are the most common clinical presentation. However, the major presenting problem in adulthood is bowel obstruction. This may be due to

Omphalomesenteric band (most frequent cause), Internal hernia through vitelline duct remnants, Volvulus occurring around vitelline duct remnants, T-shaped prolapse of both efferent and afferent loops of intestine through a persistent vitelline duct, fistula at the umbilicus in a neonate or Acting as a lead point for intussusception

There are a vast number of stated complications of MD, including from diverticulitis (± enteroliths), tumour formation, fistulation, torsion and incarceration into herniae (a Littre hernia)

Return to question

Return to home page

The text is entirely the opinion of the author and does not necessarily reflect that of RUH NHS Trust or the Bristol Radiology Training Scheme. Website content devised by Paul McCoubrie.