What is the accuracy of radiography for transitional cell carcinomas (TCCs) imaging?

Updated: Aug 21, 2016
  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Eugene C Lin, MD  more...
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Answer

Answer

Plain radiographic findings, such as calcifications, are not specific in the diagnosis of urothelial tumors. Discernible areas of a coarse, punctate pattern of calcification with a mucosal lesion on excretory urography or retrograde pyelography may suggest TCC. An important role for plain radiography is in searching for evidence of osseous metastases that may herald renal malignancy.

Multidetector-row CT is replacing IVU in the evaluation of hematuria, although IVU is still being used. The early detection of small urothelial tumors demands a meticulous IVU technique. Accurate demonstration of the pelvocaliceal system requires abdominal compression to distend the collecting systems, and oblique imaging or tomography may also be necessary. Diuresis multidetector-row CT with contour reformatting of the axial records may be useful. This technique does not require abdominal compression. Early experience with this method has been most positive because the CT technique demonstrates not only the opacified lumen but also the surrounding soft tissue anatomy.

Filling defects with dilated calyces are easily seen and are readily diagnosed. Hydronephrosis with renal enlargement is easily confused with uncomplicated primary pelvic hydronephrosis; antegrade/retrograde pyelography is usually required for diagnosis.

Adequate depiction of the ureters is difficult, and prone, oblique, or even spot images obtained during fluoroscopy may be required at urography. If an area of constant narrowing of the ureters is seen on more than 1 image and if it cannot be explained by the presence of a crossing vessel or a peristaltic wave, a tumor must be suspected. A meticulous urographic examination (radiographic or multidetector-row CT) can prevent unnecessary pyelography/ureterography in the majority of cases.

Importantly, if the demonstration of the pelvicaliceal system at excretion urography or CT is poor, an upper-tract tumor may be missed, particularly when a decoy of a bladder tumor is present. The coexistence of upper- and lower-tract tumors is not rare.

The sensitivity and specificity with regard to the upper urinary tract pathology are 67% and 91%, respectively, for IVU and 56% and 94%, respectively, for ultrasonography. For both techniques combined, the sensitivity and specificity are 79% and 88%, respectively. IVU has a 70% accuracy rate in the diagnosis of bladder TCC. The role of radiology is in demonstrating the upper urinary tract, both at the time of the initial diagnosis and during the follow-up of urothelial cancer. The statistics for multidetector-row CT are now under investigation.

Retrograde pyelography is useful when the kidney cannot be visualized with IVU or when an intravenous approach cannot be performed because of renal disease or an adverse reaction to contrast agents. Retrograde pyelography in combination with brush biopsy is a highly reliable method for making a definitive diagnosis of TCC. The results are considered diagnostic in 85% of cases.

If spot filming is the imaging technique, this should be performed in an appropriate fluoroscopic digital unit where serial images can be obtained. This may be done during diuresis urography (infusion IVU with 300 mL of 30% contrast media) or during antegrade/retrograde pyelography.

Approximately 5% of ureteric TCCs grow intramurally, resulting in a stricture rather than a filling defect. Radiologically, distinguishing this type of tumor from stricture is impossible. However, at CT, a thickened ureteric wall with stranding may be seen.


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