CT UROGRAM C+ (last updated 6/20/2016, last reviewed 02/07/2022)
INDICATION: Transitional cell carcinoma, Urothelial Neoplasm, Hematuria
SERIES
- 3mm Axial pre
- 1mm Axial urogram
- 3mm Coronal (pre, urogram)
- 3mm Sagittal (pre, urogram)
- Coronal MPR urogram
| PRECONTRAST | UROGRAM PHASE |
POSITIONING/MODE
|
supine/helical |
supine/helical |
kV/mA/rot time
|
per scanner protocol CareDose/iDose/ASIR Care kV 120 to 140 kVp </= 1 sec |
per scanner protocol CareDose/iDose/ASIR Care kV 120 to 140 kVp </= 1 sec |
DETECTOR COLLIMATION
|
16 x 1.5mm (S16) 24 x 1.2mm (D64) |
16 x 1.5mm (S16) 24 x 1.2mm (D64) |
SLICE THICKNESS
|
3mm |
1mm |
PITCH
|
0.6 to 1.2 |
0.6 to 1 |
KERNAL
|
std |
std |
SFOV
|
300 to 350 mm |
300 to 350 m |
COVERAGE
|
diaphragm -> pubic symphysis |
diaphragm -> pubic symphysis |
ACQUISITION
|
craniocaudal |
craniocaudal |
ORAL CONTRAST
|
water |
water |
IV CONTRAST
|
none |
35 mL Isovue 300, 100 mL saline ~wait 7 min~ 90 mL Isovue 300, 30 mL saline |
INJECTION RATE
|
--- |
3.5 to 4 mL/sec |
SCAN DELAY
|
--- |
80 to 90 sec after second injection |
RESPIRATION
|
Inspiration |
Inspiration |
POSTPROCESSING
|
3mm Coronal and Sagittal |
3mm Coronal and Sagittal Coronal MPR |
NOTES: No positive oral contrast. May use water as oral contrast. Just prior to scanning the patient, give 1-2 cups of water in order to distend the stomach.
Split bolus technique: The patient is given 35 mL of intravenous contrast and 100 mL saline after the non-contrast exam, but prior to the imaging of the mixed nephrographic/exretory ("Urogram") phase. This is to allow contrast to progress into the collecting system and provide excretory phase images, “CT Urogram”. Seven minutes after the administration of the 35 mL of intravenous contrast, the patient is given 90 mL of intravenous contrast. The postcontrast phase is then obtained. Right before setting up for the contrast-enhanced scan, have the patient lie prone for 30 seconds and then set up for the scan with the patient lying supine. This maneuver will help empty the contrast from the renal pelvis to the ureters.
Postcontrast phase reformats:
CT Urogram- Thin sagittal and coronal (3mm x 3mm) of the entire data set, and thick slab (3cm x 3mm) coronal MPR reconstruction should be performed of the opacified renal pelvis, ureters, and bladder. 3D of the collecting system can be performed, as needed or requested.
Optional: Coronal/ oblique coronal thick volume slabs (1cm x 3mm) MPRs thru both kidneys and renals veins should be performed. The plane best depicting the mass and its relationship to the vessels and collecting system is chosen. The oblique coronal plane parallel to the renal vein and renal hila is often the best obliquity. These reconstructions can be helpful for localization of upper and lower pole masses and staging (ie. renal vein and IVC involvement). Curved reformatted MPRs may be helpful. Shaded surface and volume-rendered or MIP 3D displays during the parenchymal phase may be helpful for exophytic lesions, but the coronal/ oblique coronal thin slice and thick volume slab MPRs thru both kidneys and renal veins are often more helpful in the staging of the renal cancer.
Occasionally, an arterial phase will be requested to evaluate the renal arteries and their relationship to a renal mass or UPJ obstruction. (see CTA-Renal mass or CTA-Renal mass-Urogram protocols)