In vivo positron emission tomography imaging of decreased parasympathetic innervation in the gut of vagotomized patients.

Abstract

Parasympathetic neuropathy is a key feature in many common disorders, including diabetes, neurological disorders, and cancers, but few objective methods exist for assessing damage to the parasympathetic nervous system, particularly in the gastrointestinal system. This study aimed to validate the use of 11 C-donepezil positron emission tomography (PET) to assess parasympathetic integrity in a group of vagotomized patients. Sixteen healthy controls and 12 patients, vagotomized due to esophagectomy, underwent 11 C-donepezil PET, measurement of colonic transit time, quantification of plasma pancreatic polypeptide (PP), and assessment of subjective long-term symptoms. Vagotomized patients had significantly decreased PET signal in the small intestine and colon compared with healthy controls (5.7 [4.4-7.9] vs 7.4 [4.5-11.3], P=.01 and 1.4 [1.1-2.1] vs 1.6 [1.4-2.4], P<.01, respectively). Vagotomized patients also displayed a significantly increased colonic transit time (2.9±0.9h vs 1.9±0.8h), P<.01 and increased volumes of the small intestine and colon (715ccm [544-1177] vs 443ccm [307-613], P<.01 and 971ccm [713-1389] vs 711ccm [486-1394], P=.01, respectively). Patients and controls did not differ in PP ratio levels after sham feeding, but PP ratio at 10minutes. after sham feeding and PET signal intensity in the small intestine was positively correlated (P=.03). We found significantly decreased 11 C-donepezil signal in the intestine of vagotomized patients, supporting that 11 C-donepezil PET is a valid measure of intestinal parasympathetic denervation.