Does the patient have renal inflammatory disease

The study is done to detect the presence of renal inflammatory disease and to detect its complications. Ideally the study consists of a non-contrast scan thru the kidneys followed by a contrast enhanced scan from the diaphragm thru the symphysis. The contrast enhanced scans are ideally at about 70-80 seconds post injection although some folks will suggest studies be done in the excretory phase at 4-5 minutes post injection. Scans are done with both thick and thin section CT scans and reconstructed with axial and multiplanar imaging. The coronal plane is especially valuable.

The CT scan for suspected renal inflammatory disease have several key points as well as several potential pitfalls.

1. The non-contrast scans are obtained to look for renal calcifications.
2. The presence of renal inflammatory disease is best seen with IV contrast. I prefer venous phase for detection of inflammatory disease although it may be also seen on arterial or delayed phase imaging.
3. Evaluation of the kidneys also needs to define whether concurrent renal abscess is present.
4. Renal inflammatory changes can at times be confused with renal infarction.
5. Renal inflammatory changes can also at times (rare) be confused with transitional cell carcinoma (TCC)
6. There is a range of renal infections including XGP but the appearance is usually different
7. Review of the bladder is also important to exclude concurrent involvement.