This procedure is indicated to know whether there are ACE Inhibitor drug (like Captorpril) inducible changes in the appearance of a dynamic renal scintigraphy or not which in turn helps to decide whether there is insufficiency in the renal arterial blood supply which warrants intervention to manage the hypertension better.

Information sought:
1. Baseline functional status of the kidneys.
2. Whether cortical uptake is affected by prior captopril administration before test.
3. Baseline Tubular Transit Status of the kidneys & whether it is prolonged by captopril.

Patient scheduling:
Some patients may require single “Post-Captopril” scan as a screening test first and based on the outcome the need for a “Baseline” scan on another day may be decided by the physician.
Some patients will definitely require a complete work up with both a baseline “Pre-Captopril” scan and a “Post-captopril” scan. Both the scans can be performed on a single day with few hours interval or on different days particularly if there are findings in the first scan which can corrupt the data in the second scan if performed on the same day. It is always necessary for the physician to review the baseline scan first and decide whether it is okay to proceed with a captopril scan.
The information on the drugs already patient is taking is very important to know whether patient is on any ACE Inhibitor or not. For patients who are on ACE Inhibitor medication already, the physician has to decide whether it is safe to take off the captopril or other ACE Inhibitors to perform a “Baseline scan”.

Patient Preparation:
Adequate hydration is essential before all renogram studies. Ensuring that the patient drinks water or other beverages while waiting for the procedure (about 30 minutes before injection) will be more reliable.
For the captopril scan, BP should be recorded first and then a 50 mg tablet (25 mg for children) should be crushed and given with water for performing the scan 45 min to 1 hour later.

PRECAUTIONS FOR CAPTOPRIL SCAN
Diuretic medications like lasix are known to potentiate the effect of captopril.
Patients who are kept fasting for other reasons should receive iv fluids accordingly in consultation with the referring physician.
Since captopril is given orally, solid food intake should be avoided to ensure good absorption of the drug.
Since captopril can produce postural hypotension, patient should not be allowed to walk around or stand erect. BP should be recorded at least just before acquiring the scan.

Patient Information Same as in Diuretic Renogram Protocol.
Renal Doppler, Renal MRA & Renal Angio reports in any.

Dose preparation Same as in Diuretic Renogram Protocol.
For same day protocol second dose may have to be higher.
Higher dose is required if abdominal aorta is to be visualized well in the rapid first pass phase.

Patient positioning Same as in Diuretic Renogram Protocol.
Erect position not allowed.

Image Acquisition parameters
Same as in Diuretic Renogram Protocol.

Radiotracer administration:
Same as in Diuretic Renogram Protocol

Delayed image
Same as in Diuretic Renogram Protocol

Image and Renogram Curve Processing
Same as in Diuretic Renogram Protocol

Important Quantitative parameters
Same as in Diuretic Renogram Protocol

Documentation on Hard copy
Same as in Diuretic Renogram Protocol

It should be possible to compare the image frames, ROI’s used and the Renogram curves between the baseline scan and the captopril scan from the hard copy..