الفهرس 
Anatomy of the Urinary BladderOnly 14 pages are availabe for public view
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Abstract
Urinary bladder carcinoma is the most common malignancy involving the urinary tract. Cigarette smoking and specific occupational exposures are the main known causes of UBC. Chronic infection by Schistosoma haematobium is a cause of squamous cell carcinoma of the bladder. Pre-neoplastic lesions of the urinary bladder including proliferative and metaplastic lesions, these changes have a significantly increased risk for the development of transitional cell carcinoma of the urinary bladder.
Cystoscopy and biopsy are the standard of reference for bladder evaluation, but imaging is important for accurate staging and treatment planning. In Plain Radiography the calcification of the wall of the bilharizial bladder usually appears as a continuous curved line of calcification and the neoplasm interrupts the continuity of the linear calcification. The traditional initial radiological investigation has been intravenous urography, a primary tumor may appear as a small-capacity, thick-walled bladder or as a focal mass. The utilization of ultrasonography as the initial radiological investigation for detection of bladder carcinomas in patients presenting with hematuria is recommended. Sonography is not routinely used for staging cancer of the urinary bladder; the tumor often appears as a polypoid or plaque like, hypoechoic lesion that may project into the bladder.
The major role of CT in bladder carcinoma is to stage rather than to detect the primary tumor. It is inaccurate for early stage. In the nephrographic phase, the enhancing tumor can be visualized against a background of low-attenuation urine within the bladder. On delayed scanning, the lesion appears as a mural nodule against a background of high-attenuation contrast material within the bladder.
Presently, MR imaging is the modality of choice in imaging urinary bladder neoplasms. MR urography can easily allow diagnosis of urinary tract dilatation and detect the level of obstructions with accuracy up to 100%.
On T1-weighted images, the bladder wall and urothelial tumor are intermediate in signal intensity yet, the tumor is intermediate in signal intensity on T2-weighted images. The stalk of papillary transitional cell carcinoma shows lower signal intensity than tumor on T2WI, less enhancement on dynamic images and stronger enhancement on delayed enhanced images.
Squamous cell carcinoma In contrast to urothelial carcinoma is sessile rather than papillary, and pure intraluminal growth is not seen. Multiplanar MR imaging can demonstrate the presence and precise location of the bladder diverticular neck. On T2-weighted images, focal areas of high signal intensity from mucin are highly suggestive of urachal carcinoma.
Typically, leiomyomas exhibit intermediate signal intensity on T1-weighted images and low signal intensity on T2-weighted images. Rhabdomyosarcoma has low signal intensity on T1-weighted images and high signal intensity on T2-weighted images with heterogeneous enhancement. Multiple grapelike intraluminal masses are highly suggestive of botryoid rhabdomyosarcoma. Low signal intensity on T1-weighted images and a target sign on T2-weighted images are highly suggestive of a plexiform neurofibroma. Hemangiomas are low to intermediate signal intensity on T1-weighted images and markedly high signal intensity on T2-weighted images. Larger lesions of low signal intensity on T2-weighted images are likely to be Solitary Fibrous tumor.
In the arterial phase of contrast enhancement, bladder tumors enhance more than the muscle, 85% of the tumors showed early, intense enhancement on images obtained beginning 20 seconds after gadolinium administration, 15% of tumors showed heterogeneous enhancement at 20 sec, or superficial enhancement on delayed images.
Accurate preoperative staging is the most important factor in determining the appropriate management of bladder carcinoma. According to the pathological results of TUR-performed patients; the accuracy of spiral CT and MRI in preoperative staging of bladder tumors was 41.6% and 83.3%, respectively. In dynamic MRI, Staging accuracy improved to 85% and 82% in differentiating superficial from invasive tumors and organ-confined from non-organ-confined tumors, respectively.
Metastatic lymph nodes have no specific appearance on T1- or T2-weighted images but enhance early, simultaneously with the bladder cancer. A limitation of both CT and MR imaging is the detection of metastasis in normal-sized lymph nodes. Improved MR detection of pathologic lymph nodes has been achieved with an intravenous suspension of ultra small iron particles, ferumoxtran-10.
Early detection of bladder cancer is important, since up to 47% of bladder cancer–related deaths may have been avoided. The role of newer MR imaging sequences in the diagnosis and local staging of bladder cancer continues to evolve. MR imaging with its advances in technology have made multipara¬metric MR imaging feasible for the local staging of bladder cancer to optimize treatment. It becomes an important tool in the early diagnosis and presurgical assessment of urinary bladder cancers. Although ultrasound and CT is the initial imaging modality to detect liver metastases on one hand ,and Bone scan to detect bone metastases on the other hand ,MRI is still more superior and accurate in their detection and evaluation because of its high tissue differentiation and multiple sequences with its new advances in diffusion sequences.
Urinary bladder carcinoma is the most common malignancy involving the urinary tract. Cigarette smoking and specific occupational exposures are the main known causes of UBC. Chronic infection by Schistosoma haematobium is a cause of squamous cell carcinoma of the bladder. Pre-neoplastic lesions of the urinary bladder including proliferative and metaplastic lesions, these changes have a significantly increased risk for the development of transitional cell carcinoma of the urinary bladder.
Cystoscopy and biopsy are the standard of reference for bladder evaluation, but imaging is important for accurate staging and treatment planning. In Plain Radiography the calcification of the wall of the bilharizial bladder usually appears as a continuous curved line of calcification and the neoplasm interrupts the continuity of the linear calcification. The traditional initial radiological investigation has been intravenous urography, a primary tumor may appear as a small-capacity, thick-walled bladder or as a focal mass. The utilization of ultrasonography as the initial radiological investigation for detection of bladder carcinomas in patients presenting with hematuria is recommended. Sonography is not routinely used for staging cancer of the urinary bladder; the tumor often appears as a polypoid or plaque like, hypoechoic lesion that may project into the bladder.
The major role of CT in bladder carcinoma is to stage rather than to detect the primary tumor. It is inaccurate for early stage. In the nephrographic phase, the enhancing tumor can be visualized against a background of low-attenuation urine within the bladder. On delayed scanning, the lesion appears as a mural nodule against a background of high-attenuation contrast material within the bladder.
Presently, MR imaging is the modality of choice in imaging urinary bladder neoplasms. MR urography can easily allow diagnosis of urinary tract dilatation and detect the level of obstructions with accuracy up to 100%.
On T1-weighted images, the bladder wall and urothelial tumor are intermediate in signal intensity yet, the tumor is intermediate in signal intensity on T2-weighted images. The stalk of papillary transitional cell carcinoma shows lower signal intensity than tumor on T2WI, less enhancement on dynamic images and stronger enhancement on delayed enhanced images.
Squamous cell carcinoma In contrast to urothelial carcinoma is sessile rather than papillary, and pure intraluminal growth is not seen. Multiplanar MR imaging can demonstrate the presence and precise location of the bladder diverticular neck. On T2-weighted images, focal areas of high signal intensity from mucin are highly suggestive of urachal carcinoma.
Typically, leiomyomas exhibit intermediate signal intensity on T1-weighted images and low signal intensity on T2-weighted images. Rhabdomyosarcoma has low signal intensity on T1-weighted images and high signal intensity on T2-weighted images with heterogeneous enhancement. Multiple grapelike intraluminal masses are highly suggestive of botryoid rhabdomyosarcoma. Low signal intensity on T1-weighted images and a target sign on T2-weighted images are highly suggestive of a plexiform neurofibroma. Hemangiomas are low to intermediate signal intensity on T1-weighted images and markedly high signal intensity on T2-weighted images. Larger lesions of low signal intensity on T2-weighted images are likely to be Solitary Fibrous tumor.
In the arterial phase of contrast enhancement, bladder tumors enhance more than the muscle, 85% of the tumors showed early, intense enhancement on images obtained beginning 20 seconds after gadolinium administration, 15% of tumors showed heterogeneous enhancement at 20 sec, or superficial enhancement on delayed images.
Accurate preoperative staging is the most important factor in determining the appropriate management of bladder carcinoma. According to the pathological results of TUR-performed patients; the accuracy of spiral CT and MRI in preoperative staging of bladder tumors was 41.6% and 83.3%, respectively. In dynamic MRI, Staging accuracy improved to 85% and 82% in differentiating superficial from invasive tumors and organ-confined from non-organ-confined tumors, respectively.
Metastatic lymph nodes have no specific appearance on T1- or T2-weighted images but enhance early, simultaneously with the bladder cancer. A limitation of both CT and MR imaging is the detection of metastasis in normal-sized lymph nodes. Improved MR detection of pathologic lymph nodes has been achieved with an intravenous suspension of ultra small iron particles, ferumoxtran-10.
Early detection of bladder cancer is important, since up to 47% of bladder cancer–related deaths may have been avoided. The role of newer MR imaging sequences in the diagnosis and local staging of bladder cancer continues to evolve. MR imaging with its advances in technology have made multipara¬metric MR imaging feasible for the local staging of bladder cancer to optimize treatment. It becomes an important tool in the early diagnosis and presurgical assessment of urinary bladder cancers. Although ultrasound and CT is the initial imaging modality to detect liver metastases on one hand ,and Bone scan to detect bone metastases on the other hand ,MRI is still more superior and accurate in their detection and evaluation because of its high tissue differentiation and multiple sequences with its new advances in diffusion sequences.