PATIENTS POPULATION
- Thirty subjects referred for dysphagia to the Division of Gastroenterology of our Hospital, underwent esophageal manometry, barium fluoroscopy and MR-fluoroscopy. Only after all MR-fluoroscopy examinations have been reported, the Department of Gastroenterology provided the results of the correspondent barium fluoroscopy and manometry exams.
PATIENTS PREPARATION
- All subjects fasted for at least 4 hours in order to perform MR-fluoroscopy examination in basal conditions. Before entering scan room, the ability of each patient to swallow a small amount of water in prone and supine position was tested to avoid aspiration episodes inside the magnet bore. All subjects were strictly instructed to swallow the contrast agent, during the exam, in a single act, avoiding the swallow of eventual residual.
CONTRAST AGENT
- The examinations were performed using as oral contrast agent a mixture of semi-fluid yoghurt and Gd-DTPA (0.5 M, 1:100) administered in single 20 ml boluses.
EQUIPMENT AND IMAGING PROTOCOL
- All examinations were performed on a commercially available 1,5 T scanner (Gradients 25 mT/m2, Slew Rate 800 T/m/sec, Rise Time 400 micro/sec), equipped with phased-array coil. Scans were acquired with the patients placed first in the prone and then in the supine position; no lateral acquisitions were performed. First was obtained a scout view of the thorax and upper abdomen to visualize the position and bending of the oesophagus and the gastro-oesophageal junction using breath-hold HASTE T2-weigheted sequence; thereafter were acquired MR-fluoroscopy images during the transit of contrast agent boluses through the esophageal lumen: a single slice slab T1-weighted Dynamic TURBO FLASH (TFL) sequence was positioned with a median sagittal orientation on the centre of the esophageal lumen, using the HASTE scout images to determine the optimum slice angle. Immediately before sequence start, a small amount of contrast agent (10-15 cc) was administered directly into the mouth of the examined subjects by an in-room operator.
IMAGE ANALYSIS
- MR-fluoroscopy images were reviewed by two radiologists in consensus. To perform an optimal evaluation of esophageal motility, images were reviewed in cine mode. In each patient was assessed the same set of parameters evaluated in the healthy population. Three major patterns of alterations with relative diagnostic criteria 'were considered:
1 - Achalasia: In subjects with evidence of normal esophageal calibre with smooth tapered narrowing of distal portion (> 10 mm of residual lumen), poorly relaxing GEJ and ineffective peristalsis replaced by characteristic "to-and-from" movements of the contrast agent bolus, was diagnosed early achalasia. The progressive enlargement of esophageal lumen (up to 50/65 mm) with completely disrupted peristalsis and extremely prolonged transit time (up to 20 sec., or incomplete clearance at sequence end), were retained most significant findings in the advanced disase.
2 - Diffuse esophageal spasm (DES): In the subjects in which bolus transit elicited intermittent, non-peristaltic, ineffective contractions (tertiary waves) along the whole esophageal body was diagnosed DES. Diminished esophageal calibre with irregular "corkscrew" surface of the lumen and prolonged transit time (up to 12/15 sec.), in addition with normal relaxing GEJ, were also considered significant diagnostic features.
3 - Nonspecific esophageal motility disorders (NEMD): In patients with isolated, atypical motility alterations (reflux, presence of tertiary waves but normal transit time, transient lumen narrowing, incomplete GEJ relaxation, mildly reduced esophageal clearance) were diagnosed NEMD.
