Esophageal, Reflux & Salivary Studies⁹⁹ᵐTc-sulfur colloid · ⁹⁹ᵐTc-pertechnetate

Quick Answer

Three lower-volume functional GI studies. Esophageal transit scintigraphy tracks a radiolabeled swallow to quantify transit and clearance in dysmotility (e.g. achalasia, scleroderma). Gastroesophageal reflux scintigraphy (the "milk scan" in children) detects and quantifies reflux and can assess pulmonary aspiration on delayed images. Salivary gland scintigraphy (Tc-99m-pertechnetate) evaluates gland function and duct patency, notably in Sjögren syndrome and post-radioiodine xerostomia.

The Studies (Technique & Quantitation)

• Esophageal transit: the patient swallows a Tc-99m-sulfur-colloid-labeled liquid/semisolid bolus (often single-swallow then serial dry swallows), imaged in rapid dynamic frames. An esophageal transit time / percent-clearance (or a condensed time-activity "condensed image") quantifies emptying; achalasia shows retained column with to-and-fro activity, scleroderma shows aperistaltic delayed clearance. Objective and repeatable for following therapy.
• Gastroesophageal reflux ("milk scan"): a Tc-99m-labeled feed (milk in infants) is imaged dynamically over the lower esophagus; retrograde spikes of activity above the stomach indicate reflux episodes, and delayed lung images can show aspiration. Advantages over the pH probe: physiologic, low radiation, quantifiable, and a longer continuous observation window (also detects non-acid reflux the pH probe misses).
• Salivary scintigraphy: IV Tc-99m-pertechnetate is trapped and secreted by the salivary glands (same NIS mechanism as thyroid trapping); dynamic imaging with a lemon-juice/vitamin-C sialagogue shows uptake, ductal excretion, and a salivary ejection response, grading gland hypofunction and duct obstruction.

Interpretation & Reporting

• Esophageal: report transit time/percent clearance and the pattern (aperistaltic vs obstructed vs retained column); compare across therapy.
• Reflux: report number/height of reflux episodes, the quantified reflux index, gastric emptying if assessed, and any aspiration on delayed lung images.
• Salivary: report uptake and excretory (post-sialagogue) function per gland, distinguishing parenchymal hypofunction (Sjögren, post-radioiodine) from ductal obstruction (sialolithiasis).

Three functional GI studies, three questions

Three lower-volume functional studies each answer a specific question. Esophageal transit scintigraphy quantifies transit/clearance in dysmotility (achalasia, scleroderma). Gastroesophageal reflux scintigraphy — the pediatric "milk scan" — detects and quantifies reflux physiologically over a long window and can show pulmonary aspiration on delayed images (advantages over the pH probe: physiologic, low-dose, quantifiable). Salivary scintigraphy (Tc-99m-pertechnetate, ± lemon-juice sialagogue) grades gland function and duct patency in Sjögren and post-radioiodine xerostomia.

The milk scan beats the pH probe on physiology and detects non-acid reflux and aspiration over a long window — but a short acquisition can miss intermittent reflux, so imaging time and quantitation matter. Salivary pertechnetate uses the same NIS trapping mechanism as the thyroid, which is why post-radioiodine xerostomia and Sjögren both reduce uptake/excretion.

Distinguish salivary parenchymal hypofunction (reduced uptake — Sjögren, post-I-131) from ductal obstruction (preserved uptake, impaired post-sialagogue excretion — sialolithiasis). Esophageal transit objectively grades achalasia (retained to-and-fro column) versus scleroderma (aperistaltic delayed clearance) and follows therapy — a reproducible functional complement to manometry/endoscopy.

High-Yield Pearls

• The pediatric milk scan images reflux physiologically over a long window, quantifies episodes, and can demonstrate aspiration (and non-acid reflux).
• Salivary scintigraphy grades uptake vs excretory function — separating parenchymal (Sjögren, post-I-131) from ductal (stone) disease.
• Esophageal transit quantifies and follows achalasia/scleroderma dysmotility objectively.

Common Pitfalls

• Short acquisition windows missing intermittent reflux.
• Swallowing technique/positioning artifacts in transit studies.
• Not separating parenchymal from ductal salivary dysfunction (uptake vs post-sialagogue excretion).

Related Pages

• Related: gastric emptying; tracer: radioiodine (salivary uptake context for post-I-131 xerostomia).

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