The interrenicular septum. A normal anatomical variant seen on DMSA SPECT

Area of Science:

• Nuclear medicine
• Radiology
• Pediatric nephrology

Background:

• Tc-99m DMSA scintigraphy is crucial for evaluating renal scarring in children.
• SPECT imaging may reveal additional defects not seen on planar imaging.
• The origin of these defects, whether scars or anatomical variants, remains unclear.

Purpose of the Study:

• To determine if the interrenicular septum (IRS) can be identified using Tc-99m DMSA SPECT.
• To characterize the appearance of IRS on Tc-99m DMSA SPECT.
• To differentiate IRS from renal scars.

Main Methods:

• Tc-99m DMSA SPECT imaging was performed on patients.
• Image analysis focused on identifying linear areas of absent tracer uptake.
• Comparison with ultrasound or tomography was used for anatomical correlation.

Main Results:

• The interrenicular septum (IRS) was identified on Tc-99m DMSA SPECT in 32% of patients.
• IRS presented as a linear defect from the renal hilum into the parenchyma, typically anterosuperiorly.
• Preserved renal cortical uptake distinguished IRS from true renal scars.

Conclusions:

• The interrenicular septum (IRS) is a common finding on Tc-99m DMSA SPECT.
• Recognizing the characteristic appearance of IRS is essential to avoid misdiagnosis as renal scarring.
• Tc-99m DMSA SPECT can help differentiate normal anatomical variants from pathology.