Upper urinary tract tumors: how does the contrast enhancement measured in a split-bolus CTU correlate to histological staging?
BACKGROUND
Computed tomography urography (CTU) is used widely in the work-up of patients with symptoms of urinary tract lesions. Preoperative knowledge of whether a tumor is invasive or non-invasive is important for the choice of surgery. So far there are no studies about the distinction of invasive and non-invasive tumors in ureter and renal pelvis based on the enhancement measured with Hounsfield Units.


OBJECTIVE
To examine the value of CTU using split-bolus technique to distinguish non-invasive from invasive urothelial carcinomas in the upper urinary tract.


METHODS
Patients who underwent nephroureterectomy between 2006 and 2011 and who had split-bolus CTU prior to surgery were included. The images were available electronically. The attenuation values before and after administration of iodine-based contrast media were measured. The radiology, patient, and pathology records were reviewed.


RESULTS
Of the 158 patients who underwent unilateral nephroureterectomy 69 fulfilled the inclusion criteria. Histopathological examination revealed 31 patients with non-invasive and 38 with invasive urothelial carcinoma. Neither absolute attenuation nor change in attenuation values obtained at CTU could distinguish between invasive and non-invasive lesions. No patients had a CTU within the last year before the examination that resulted in surgery.


CONCLUSIONS
A split-bolus CTU cannot distinguish between invasive and non-invasive urothelial tumors in the upper urinary tract, but the examination is useful to diagnose a tumor in the renal pelvis and the ureter.
Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev, Denmark Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark karen@lindgandrup.dk.
Karen L
KL
Gandrup
Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark Department of Urology Copenhagen University Hospital Herlev, Herlev, Denmark.
Jørgen
J
Nordling
Department of Pathology, Copenhagen University Hospital Herlev, Herlev, Denmark.
Ingegerd
I
Balslev
Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev, Denmark Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Henrik S
HS
Thomsen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007479:Iopamidol / Q000031:analogs & derivatives; D007682:Kidney Pelvis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014513:Ureter / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D014516:Ureteral Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D014571:Urologic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery
D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol
Abdominal/GI; CT; adults; neoplasms – primary; tissue characterization; ureters