Difference Between Sinogram and Fistulogram in CT Scan

Medical imaging plays an important role in diagnosing abnormal tracts, infections, and fluid collections inside the body. Two commonly used diagnostic procedures for evaluating abnormal tracts are Sinogram and Fistulogram.

Although both procedures involve injecting contrast media to visualize a tract, they are used for different clinical conditions.

In this article, we will understand the difference between Sinogram and Fistulogram, their purpose, and how the procedures are performed.

What is a Sinogram?

A Sinogram is a radiological imaging procedure used to evaluate a sinus tract.

A sinus tract is a blind-ended abnormal channel that opens on the skin surface but does not connect to another internal organ.

Common Causes of Sinus Tract

Post-surgical infection
Chronic abscess
Osteomyelitis
Foreign body infection
Tuberculosis sinus

How Sinogram is Performed

The external opening of the sinus is identified.
A small catheter or cannula is inserted into the opening.
Water-soluble contrast media is injected slowly.
Imaging is performed using X-ray or CT scan.
The images help visualize the length, direction, and depth of the sinus tract.

Purpose of Sinogram

To determine the extent of the sinus tract
To identify hidden abscess cavities
To help surgeons plan surgical treatment

What is a Fistulogram?

A Fistulogram is an imaging procedure used to evaluate a fistula tract.

A fistula is an abnormal connection between two internal organs or between an organ and the skin.

Common Types of Fistula

Anal fistula
Enterocutaneous fistula
Rectovaginal fistula
Biliary fistula

How Fistulogram is Performed

The external fistula opening is identified.
A catheter is inserted into the tract.
Contrast material is injected carefully.
Imaging is done using fluoroscopy, X-ray, or CT scan.
The images show the communication between organs.

Purpose of Fistulogram

To identify the origin and pathway of the fistula
To detect internal communication
To assist surgeons in planning fistula repair surgery

What is a Sinogram?, What is a Fistulogram?

Key Difference Between Sinogram and Fistulogram

Feature	Sinogram	Fistulogram
Definition	Imaging of a sinus tract	Imaging of a fistula tract
Connection	Blind-ended tract	Connects two organs or organ to skin
Purpose	Shows length and direction of sinus	Shows communication between structures
Common Causes	Infection, abscess, post-surgery	Inflammatory disease, surgery complications
Imaging Methods	X-ray or CT	Fluoroscopy, X-ray, CT

Summary

Both Sinogram and Fistulogram are important diagnostic imaging procedures used to study abnormal tracts in the body.

Sinogram is used for a blind-ending sinus tract.
Fistulogram is used for a tract connecting two organs or structures.

These procedures help doctors understand the exact anatomy of the tract, detect infection, and plan appropriate surgical treatment.

✔ Radiographic Gyan Tip:
Understanding the difference between Sinogram and Fistulogram is important for radiology technologists, especially when assisting in contrast studies and CT imaging procedures.

If you have any questions regarding this topic, feel free to comment on Radiographic Gyan.

Thursday, March 19, 2026