Imaging of urinary bladder carcinoma

Imaging of urinary bladder carcinoma by Dr. Prajwal Dhakal

1. Imaging of Urinary bladder carcinoma PRAJWAL DHAKAL

2. Introduction Fourth most common malignancy in men. T enth most common in female Occur 3- 4 times more frequently in male. high recurrence rate, necessitating long term surveillance after initial treatment. Up to 47% of cancer related death can be avoided so early diagnosis is important S urvival of the patients with bladder cancer is longer than those with most other cancers.

3. Pathologic features About 90% of bladder tumors are urothelial in origin ( i.e. transitional cell carcinomas ). Squamous cell carcinomas account for 6%–8% Adenocarcinomas are rare and typically represent urachal cancer. Up to 25% of urothelial cancers have a mixed histology (poor prognosis).

4. Risk factors Cigarette smoking in 50%–60% of men and one-third of women. occupational exposure to chemical carcinogens such as aniline dyes therapeutic irradiation of neighboring organs use of alkylating agents although it is rare . genetic predisposition to the development of urothelial tumors in some families. Risk factors for squamous cell cancer include long-term catheterization, nonfunctioning bladder, urinary tract calculi, and chronic infection by Schistosoma hematobium

5. Pathologic features Urothelial tumors are classified not invading muscle (superficial or papillary). Approximately 80%–85% of urothelial tumors invading muscle ( nonpapillary ) Approximately 20%–25% of bladder cancers are muscle invasive and includes squamous and adenocarcinoma .

6. Anatomy extra peritoneal structure, with peritoneum covering only the superior surface of the bladder (bladder dome). The orifices of the ureters at the ureterovesical junction are joined by an elevated ridge covered by mucosa (the interureteric ridge). The bladder trigone is a triangular region on the inferior wall, marked at its corners by the ureterovesical junction and the urethra.

7. Clinical staging and management most commonly present with painless hematuria (80%–90% of cases ). CT/ Cystoscopy Some institutions perform computed tomographic (CT) urography for triage prior to cystoscopy, whereas others use cystoscopy as the first line of investigation . Magnetic resonance (MR) imaging of the pelvis is usually performed for T (tumor) staging once bladder cancer has been diagnosed, although its use is not widespread.

8. Cystoscopic staging is an initial and important part of pretreatment planning. T o assess the pathology, grade, and depth of these tumors c ystoscopic biopsy of suspicious-looking bladder lesions is performed. Transurethral resection of bladder tumor ( TURBT) has also been used for deep biopsy to assess for muscle-invasive tumors . Cross-sectional imaging is usually performed afterward for disease staging in patients who are thought to have solid tumors.

9. TNM Staging Tumor Tx Primary tumor cannot be evaluated T0 No primary tumor Ta Noninvasive papillary carcinoma Tis Carcinoma in situ T1 Tumor invades connective tissue under the epithelium (surface layer) T2 Tumor invades muscle T2a Superficial muscle affected (inner half) T2b Deep muscle affected (outer half) T3 Tumor invades perivesical fat T3a Tumor is detected microscopically T3b Extravesical tumor is visible macroscopically T4 Tumor invades the prostate gland, uterus, vagina, pelvic wall, or abdominal wall

10. N – Regional Lymph Nodes NX: Regional lymph nodes cannot be assessed N0:No regional lymph node metastasis N1:Metastasis in a single lymph node in the true pelvis ( hypogastric , obturator , external iliac, or presacral ) N2:Metastasis in multiple regional lymph nodes in the true pelvis ( hypogastric , obturator , external iliac, or presacral ) N3: Metastasis in a common iliac lymph node(s)

11. M- Metastasis M0: No distant metastasis M1a: Non regional lymph nodes M1b: Other distant metastasis

12. Treatment Non-Muscle-invasive Disease Non-muscle-invasive tumors are usually treated with TURBT. in patients with bulky Ta lesions or T1 tumors, the current trend is to perform repeat TURBT 2–6 weeks after the first TURBT. adjuvant intravesical chemotherapy ( eg , with mitomycin C or gemcitabine) or immunotherapy (with bacille Calmette-Guérin [BCG]). Muscle-invasive Disease For muscle-invasive tumors, radical cystectomy is the established treatment with meticulous extended bilateral lymphadenectomy , since extent of lymphadenectomy is associated with survival.

13. Imaging Consideration Plain Xray IVU CT urography MRI

14. X-ray X-ray has limited role Calcification in bladder cancer is visible on plain films in approximately 0.5% of bladder cancer, usually transitional or squamous cell carcinoma. It may be focal, linear, punctate or coarse

15. USG Superficial bladder tumors may be seen as mass lesions of intermediate echogenicity . May be sessile or papillary, the latter being easier to detect, sometimes down to 2-3 mm diameter. Tumor may be seen infiltrating the bladder wall and extending through it in advanced cases

16. IVU Both IVU and ultrasound will fail to diagnose a substantial proportion of cases (with a detection rate as low as 26%). May demonstrate tumor but is more important in diagnosing alternative pathologies (renal cell carcinoma, calculi etc ). I t has also been used to access upper urinary tract for detection of synchronous or metachronous lesion I n some institution it has been used as a yearly surveillance investigation for detecting these lesion. However, its use is being controversial.

17. Computed Tomography CT urography has a sensitivity and specificity of over 90% for the diagnosis of bladder cancer in patients with hematuria. Despite these encouraging results, CT urography cannot be used as a replacement for diagnostic cystoscopy in most patients with suspected bladder cancer.

18. CT: does not allow the confident diagnosis of flat lesions and lesions at the bladder base adjacent to the prostate gland ( in BEP). Difficulty is differentiating tumor recurrence from inflammatory wall thickening (following endovesical chemotherapy and scar tissue after TURBT. The homogeneous opacification of urine has been claimed to improve bladder cancer detection, particularly on the nondependent surface of the bladder

19. It is possible to visualize bladder wall enhancement and thickness on nephrographic phase CT scans. Virtual cystoscopy has been performed with the installation of 300–500 mL of air or carbon dioxide into the bladder lumen via a catheter. S ome small series have shown CT cystoscopy to have a sensitivity of over 90 %.

20. MR Imaging Requires high spatial resolution, thin sections (3 mm), and a large matrix. M ore accurate staging than CT : high soft-tissue contrast resolution, which allows clear differentiation between bladder wall layers. Better depict intramural tumor invasion as well as extravesical extension. Allows differentiation between muscle-invasive and non-muscle-invasive disease No ionizing radiation.

21. Local staging of bladder cancer: a multiparametric approach with conventional and functional sequences is useful. Multiparametric MRI : combination of T1- and T2-weighted images and functional MRI techniques, including DCE imaging and DWI. Axial spin-echo (SE) T1-weighted images with a large FOV : for evaluating the perivesical fat planes for extravesical tumor infiltration, pelvic lymphadenopathy, and bone metastases .

22. High-resolution fast SE T2-weighted images in the three orthogonal planes with a small FOV : to evaluate the detrusor muscle for tumor depth and invasion of the surrounding organs 3D sequences offer the advantages of shorter acquisition time, volumetric coverage without intersection gaps, and an improved signal-to-noise ratio. Techniques useful in rapid pelvic imaging : non-breath-hold ultrafast SE T2- weighted sequences ( eg , single-shot fast SE and GRE sequences) and steady-state free precession imaging sequences ( eg , fast imaging employing steady-state acquisition [FIESTA ]).

23. Artifacts associated with MR imaging of bladder includes: lack of bladder distention, motion artifact chemical shift artifact

24. Dynamic Contrast Enhanced MR Imaging . The usefulness of dynamic contrast-enhanced T1-weighted MR imaging is debatable, with some studies showing that it is a useful technique and others showing that it is of no additional value The bladder tumor, mucosa, and submucosa enhance early (20sec), but the muscle layer maintains its hypointensity and enhances late (60 sec)

25. Diffusion-weighted MR Imaging Role of diffusion-weighted imaging in bladder cancer is evolving and has not yet been fully established. Provides both qualitative and quantitative information that reflects changes at the cellular level concerning tumor cellularity and cell membrane integrity . For most bladder tumors, increased cellular density manifests as increased signal intensity on diffusion-weighted images with a reduced apparent diffusion coefficient (ADC) at quantitative analysis

26. Changes in signal intensity seen on diffusion-weighted images are more useful than information from ADC measurements Diffusion-weighted imaging in bladder cancer has been evaluated in terms of diagnosis, staging, prediction of histologic grade, and assessment of the efficacy of induction chemotherapy). It has shown improved differentiation between the tumor, muscle layer, and thickened submucosa, all of which have different signal intensities at diffusion-weighted imaging.

27. Currently, MRI is the best imaging technique for local and nodal staging of bladder cancer. The main advantages of MRI are its superior soft-tissue contrast (especially T2-weighted imaging) without using radiation. The introduction of multiparametric MRI, combining anatomic and functional sequences seems promising in detection, staging, and follow-up of bladder cancer

28. Positron Emission Tomography Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose is considered to be of lesser value in the local staging of bladder cancer due to urinary excretion of the radiotracer

29. In patients with known bladder cancer, the important staging question is whether there is muscle invasion (stage T2 or higher ). The accuracy of contrast-enhanced CT in the local staging of bladder cancer is only 40%–60% . MR imaging is considered superior to CT in demonstrating the extent of bladder wall invasion ( ie , in differentiating between stage T2a and stage T2b disease ). Microscopic perivesical spread (stage T3a disease) cannot be identified at either CT or MR imaging . Recent studies have reported diffusion-weighted imaging to have a high sensitivity and specificity in the staging of bladder cancer

30. The most common site of nodal metastasis is the obturator nodes . About one in six patients presents with lymph nodes above the aortic bifurcation, and 8% have presacral adenopathy. Conventional CT and MR imaging cannot help identify metastases in lymph nodes less than 10 mm. Enlarged nodes may be reactive, so that specificity is also limited According to recent published reports, diffusion-weighted imaging has shown promise in differentiating benign from malignant lymph nodes

31. Post-treatment Surveillance Because of the high rate of local recurrence, patients with non-muscle-invasive bladder cancer must be followed up after treatment Cystoscopy , urine cytology, and imaging of the upper tract with retrograde ureteroscopy are usually performed annually. Given the high metastatic recurrence rate of muscle-invasive bladder cancer, guidelines for post- cystectomy surveillance include urine cytology, chest radiography, and abdominopelvic imaging every 3–6 months for the first 2 years .

32. Rare malignancies Urachal carcinoma Less than 0.5% of bladder cancer. Overwhelmingly adenocarcinoma Vast majority arise in the urachus immediately adjacent to the bladder vault and extends superiorly in the perivesical space towards the umbilicus and inferiorly to the bladder. Considerable extra vesical component and the position in the bladder vault should suggest the urachal rather than bladder carcinoma. Are often mucinous and two third show dystrophic calcification which may be punctate or curvilinear. Three fifth of the cases also show cystic degeneration with mucinous component

33. Lymphoma Primary nonspecific findings as large lobulated mass or focal wall thickening in middle aged to elderly female presented with gross hematuria. Usually non Hodgkins lymphoma. S econdary Common in advanced disease, being found in 13% of postmortem cases died with lymphoma

34. Mimics of urinary bladder carcinoma Inflammatory pseudotumor Pathogenesis: Unclear Can be locally aggressive and mimic malignancy Imaging: Usually solitary bladder mass ( exophytic or polypoid ) Axial T2-weighted MR image shows a lobulated polypoid mass arising from the anterior wall of the bladder with central hyperintensity (*) and low peripheral signal intensity (arrowhead).

35. endometriosis Endometriosis. (a, b) Axial T1-weighted (a) and fat-suppressed T1-weighted (b) MR images show high-signal-intensity foci (arrow) within a soft-tissue mass in the vesicouterine space, projecting into the bladder lumen. (c) Axial T2-weighted MR image shows the lesion is predominantly low signal intensity (arrow ), a finding consistent with fibrosis. (d) Axial gadolinium-enhanced fat-suppressed T1-weighted image shows homogeneous enhancement of the lesion (arrow).

36. Nephrogenic Adenoma Non neoplastic mass ( metaplastic ) due to chronic irritation (calculi, infection). Non specific findings of solitary or multiple sessile or polypoid masses. Involves lamina propria , doesn’t involve muscle layer. Anteroposterior view of the bladder obtained during intravenous urography shows an irregular lobulated filling defect at the base of the bladder. Pathologic evaluation showed urothelial carcinoma with an adjacent nephrogenic adenoma .

37. Malacoplakia Rare granulomatous inflammation which can involve any organ, urinary tract commonest. Multiple, polypoid , vascular, solid masses or circumferential wall thickening. Can invade perivesical space and even cause bone destruction. Associated with VUR and hydroureteronephrosis . ( a) Axial CT image shows marked circumferential bladder wall thickening . ( b) Photograph of the cut, resected specimen shows a friable, hemorrhagic mucosal surface and dramatic wall thickening .

38. eosinophilic cystitis Cystic eosinophilic cystitis. (a, b) Axial (a) and sagittal reconstructed (b) contrast-enhanced CT images show a thick-walled cystic mass (arrow) arising from the anterior dome of the bladder. (c) Intraoperative photograph, with the bladder wall retracted (arrowheads), shows the mass (arrow) protruding into the lumen. (d) Photograph of the cut specimen shows a circumferentially thickened wall, as seen on the CT images. (e) Photomicrograph (original magnification, 120; H-E stain) shows an intense infiltration of eosinophils deep within the muscularis

39. Schistosomiaisis Schistosomiasis . Anteroposterior radiograph (a) and axial CT image (b) of the bladder shows curvilinear calcification in the bladder wall (arrowheads), which also extends to the distal left ureter (arrow ). Calcification , representing an abundance of calcified ova, is typically seen in the chronic phase of the infection.

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41. Role of plain Xray , IVU and USG in bladder ca Role of CT in bladder ca Role of conventional MRI in bladder ca Role of dynamic contrast imaging Role of DWI Urachal carcinoma imaging features List the mimickers of urinary bladder carcinoma.