CT Urography in Hematuria - Protocol & points to remember
Important points in clinical history:
1. Infection
2. Menstruation
3. Strenuous exercise
4. Trauma
5. Glomerular cause: Proteinuria / red cell casts in urine / elevated serum creatinine
6. Blood thinners
7. Prostate complaints in elderly
8. Blood disorders eg- hemophilia
What to rule out:
1. Calculus
2. AV Malformation - arterial phase
3. Venous thrombosis - nephrogram
4. Renal mass - arterial and nephrogram
5. TCC - ureter / bladder - arterial and delayed
6. Renal vein compression - nutcracker
7. Trauma
8. Prostate enlargement
Protocol:
1. Plain study - KUB only
2. Early arterial ( 6 seconds post trigger) - KUB region only (cover entire abdomen and pelvis if for RCC)
3. Nephrogram (70 seconds post trigger) - Cover entire abdomen and pelvis
4. Delayed (8 minutes post trigger ) - KUB only
Tweaks in protocol:
1. In case of young patient with stone, you can skip arterial and nephrogram
2. you can combine the nephrogram and delayed on one study by doing split bolus
3. Use of Dual energy
4. You can delay the arterial phase to 10 seconds instead of 6 seconds
- it gives simultaneous artery and vein information with good enhancement of the vascular structures.
5. Avoid radiation to breast and testis in young
TIPS:
- Use thin MIP - to rule out calculus on plain scan, on arterial phase to rule out AVM and delayed images for collecting system
- For renal mass - don't miss the poles. See coronal and sagittal
- Small exophytic angiomyolipoma may be missed on plain scan
- For bladder polyp zoom the images, change to metastatic window and carefully look for small polyps / mucosal lesion in the bladder.
- For clear cell RCC - always look for hypervascularity and heterogeneity
- Papillary RCC can be hypovascular and homogeneous. Can be mistaken for cyst on CT SCAN. Ultrasound would be helpful
- Chromophobe RCC and oncocytoma cannot be differentiated based on the central scar
-TCC in the kidney may appear as filling defect on delayed images
- Log rolling can be performed, when you suspect bladder lesion prior to the delayed exam to mix urine and contrast
Prepared by Dr. Sharad Maheshwari
26.10.2022
Updated: 27.10.2022
If early arterial to look for RCC, why cover entire abdomen/pelvis instead of just the kidneys?
ReplyDeleteTo detect hypervascular metastasis. Its a personal preference and you can alter accordingly
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