Fourier Phase Analysis of Dynamic Antral Contraction Scintigraphy: New Software, Reference Values, and Comparisons to Conventional Gastric Emptying.

Dynamic antral contraction scintigraphy (DACS) has been used to evaluate for gastric dysmotility by measuring antral contraction frequency and ejection fraction (EF). Fourier phase image analysis has the potential to assess gastric antral contractions for dyssynchrony as has been used for analyzing nuclear cardiology ventriculography (multigated acquisition studies) for cardiac dyssynchrony. The aims of this study were to determine whether Fourier phase analysis helps to characterize antral motility physiology, whether Fourier phase analysis correlates with conventional gastric emptying scintigraphy (GES), and which DACS parameters may aid in diagnosing gastric dysmotility, particularly delayed gastric emptying (GE). Methods: DACS and GES of healthy volunteers (n = 22) were compared with patients (n = 99) with symptoms of gastroparesis. New DACS Fourier phase analysis software was developed. Results: GE was delayed (n = 53) or normal (n = 46) in patients. There was a linear correlation between the time for the stomach to empty 50% of the meal and the percentage total proximal and distal in-phase antral pixels at 30 min (r = 0.37, P = 0.0001) and 60 min (r = 0.26, P = 0.007). In healthy volunteers, the mean proximal-to-distal ratio of in-phase antral pixels increased from 1.67 (30 min) to 2.65 (120 min) (P = 0.035), and EF increased from 23% (30 min) to 32% (120 min) (P = 0.022). Multivariable regressions of percentage total proximal and distal in-phase antral pixels (30 min) and EF (60 min) were the best predictors of abnormal GE (adjusted odds ratio, 3.30 [95% CI, 1.21-9.00] and 2.97 [95% CI, 1.08-8.21], respectively). Conclusion: This study used Fourier phase analysis to analyze DACS in healthy volunteers and patients with symptoms of gastroparesis. In addition to establishing reference values, new physiologic information on antral motility was obtained. In healthy volunteers, there was an increasing proximal-to-distal ratio of in-phase antral pixels and antral EF over time after meal ingestion. The percentage total proximal and distal in-phase antral pixels at both 30 and 60 min correlated well with GE values for the time for the stomach to empty 50% of the meal. For symptomatic patients, the percentage total proximal and distal in-phase antral pixels at 30 min and the EF at 60 min after meal ingestion correlated with delayed GE on conventional GES. Thus, Fourier phase analysis of DACS appears to have potential to further aid in diagnosing gastric dysmotility in GES.

Proximal and distal intragastric meal distribution during gastric emptying scintigraphy: Relationships to symptoms of gastroparesis.

BACKGROUND: Total gastric retention (TGR) from gastric emptying scintigraphy (GES) is used for diagnosing gastroparesis (Gp), but correlates poorly with patients' symptoms. Regional intragastric meal distribution (RIMD) can also be assessed from GES. This study classified patients' meal distribution as proximal or distal to relate RIMD to symptoms of Gp. METHODS: GES studies in patients (n = 193) and control subjects (n = 21) were selected for RIMD analysis. Patients completed Patient Assessment of Upper Gastrointestinal Symptoms (PAGI-SYM) for symptom severity before GES. TGR was analyzed using % TGR, and RIMD used a proximal/distal gastric count ratio (PDCR). Results were classified as proximal or distal RIMD at 0, 1, 2, and 4 h postprandially based on their PDCR being above or below the median value of the patients. RESULTS: Patients with delayed GE and immediate post-meal ingestion distal distribution had more severe early satiety and regurgitation. Distal distribution at 1 h had more severe early satiety and loss of appetite compared to proximal distribution. Patients with delayed GE and proximal distribution at 4 h had more severe nausea, retching, and vomiting compared to 4 h distal distribution. Severely delayed 4 h proximal distribution had more nausea than severely delayed 4 h distal distribution. CONCLUSIONS: Increased early distal IMD in patients with delayed GE was associated with regurgitation and early satiety whereas increased late proximal IMD was associated with nausea, retching, and vomiting. Differentiating proximal from distal meal distribution patterns helps to relate symptoms to gastric dysfunction and may be helpful for directing therapy.

Addition of small-bowel transit scintigraphy to gastric emptying for assessment of patients with upper gastrointestinal symptoms.

BACKGROUND: Dyspeptic symptoms are not well correlated with gastric emptying (GE) results. AIMS: To determine (a) prevalence of delayed SB transit (SBT) in patients undergoing GE scintigraphy for symptoms of gastroparesis; (b) symptoms associated with delayed SBT. METHODS: Patients with symptoms of gastroparesis underwent combined GE and SBT scintigraphy (GES/SBTS). Patients ingested a mixed solid (S)-liquid (L) meal with egg whites labeled with 500 µCi Tc-99 m sulfur colloid and water with 125 µCi In-111 DTPA. Retained S and L gastric activity and percent of L In-111 activity in terminal ileum (TI) and/or cecum/colon at 6 h were determined. Patient Assessment of Gastrointestinal Symptoms (PAGI-SYM) assessed symptoms from 0 (none) to 5 (very severe). KEY RESULTS: Of 363 patients, 174 (47.9%) had delayed S GE, 141 (38.8%) delayed L GE, and 70 (19.3%) delayed SBT. Delayed SBT was seen in 24 (6.6%) with normal S GE and 46 (12.7%) with delayed S GE. Patients with isolated delayed SBT had highest symptom scores for postprandial fullness (3.5), stomach fullness (3.4), nausea (3.2), bloating (3.2), compared to isolated delayed S GE who had highest symptom scores for postprandial fullness (3.7), nausea (3.6), stomach fullness (3.4), and early satiety (3.3). CONCLUSIONS & INFERENCES: Delayed SBT occurred in 19.3% of dyspeptic patients using GES/SBTS. While postprandial and stomach fullness were common to both delayed S GE and delayed SBT, early satiety was associated with delayed S GE whereas bloating was associated with delayed SBT. Thus, SBTS can augment GES to help explain some symptoms associated with dyspepsia and suspected gastroparesis.