MR-tomographische Echtzeit-Darstellung der reduzierten Magenmotilität bei Patienten mit idiopathischem Parkinson Syndrom im Vergleich zu gesunden Kontrollpersonen

Delayed gastric emptying is one of the non-motor symptoms of Parkinson´s disease (PD). It is a frequent phenomen and already emerges in the early stages of the disease [Goetze et al. 2006; Djaldetti et al. 1996]. Resulting symptoms such as nausea and vomiting caused by delayed gastric emptying are of less importance for PD patients than its possible influence on the L-Dopa resorption and the resulting motor fluctuations. Furthermore considering delayed gastric emptying as an early indicator of the disease it is of interest in the context of early diagnosis and therapy. Knowledge about gastric physiology and pathophysiology has been generally limited; especially concerning Parkinson´s disease. Among other things this is due to a lack of diagnostic ability [Horowitz et al. 2001]. The aim of this pilot study was to analyse the feasibilty of real-time MRI to examine gastric motility in its application on PD patients as compared to healthy controls and to gain first data about possible changes in PD patients. For this purpose, ten PD patients and ten healthy volunteers were examined. The subjects were selected based on age, BMI and gender. The average duration of the disease in PD patients was 2.7 years. Six of the patients were drug-naive patients. All patients underwent real-time MRI of the stomach after an overnight fast and a standardized test-meal. The PD patients were examined in the defined „Off“.The gastric motility index (GMI) was calculated as a measure of gastric motor function. The GMI was calculated for each patient using the formula: GMI=v*d. V and d are the velocity and the amplitude of a peristaltic wave. Additionally, all subjects were interviewed for a detailed history and underwent a thorough physical and neurological examination including the PANDA, H&Y, UPDRS and MMST. The PD patients showed a lower GMI compared to the controls (11 mm2/s [PD] vs. 16,5 mm2/s [control]). This difference was statistically not significant and can be interpreted as a trend towards a decreased gastric motility. The velocity of peristaltic waves was virtually the same in both groups (2,08 mm/s [PD] vs. 2,07 mm/s [controls]). In contrast, there was a statistically significant difference in amplitude; showing lower values in the PD patients compared to the controls (5,35 mm [PD] vs. 8,06 mm [controls]). Considering this and the formula for the GMI (GMI=v*d) the trend towards a decreased GMI in PD patients in comparison to the healthy subjects was due to a difference in the amplitude of peristaltic contractions while the velocity was consistent in both groups. The analysis of correlation showed, that the age difference in both groups (62 years [PD] vs. 53 years [controls]) was not related to the results of gastric motility, so that biased results due to age are unlikely. Further, no cluster of values of de novo patients in comparison to patients under medication could be seen in the scatter plot for GMI and amplitude. Thus, biased results through this factor are unlikely here as well. Long-term effects of medication, however, could not be excluded. This study provides first evidence, that real-time MRI can be used for examining gastric motility in PD patients, and furthermore, to visualize underlying mechanism. This represents a crucial advantage over other methods, of which the examination of certain specific aspects of gastric emptying were not possible in this way until now. Moreover, MRI is non-invasive, widely available, radiation-free, time efficient, inexpensive and provides exact data. Investigations in a large, homogenous sample of de novo PD patients, matched controls and patients with disorders affecting the gastric nervous system are necessary to determine the discriminatory power and validity of this technique.