Role of MR Virtual Cystoscopy in the Detection of Urinary Bladder Neoplasms

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Role of MR Virtual Cystoscopy in the Detection of
Urinary Bladder Neoplasms
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• Carcinoma of the bladder can be a serious and
  complex condition that is not always easy to
  diagnose with radiological methods
• Cystoscopy plays a key role in the diagnosis of
  carcinoma of the urinary bladder but it has some
  limitations

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• Recent advances in computer-assisted
  virtual-reality data- postprocessing techniques
  have led to the development of a variety of novel
  imaging techniques including virtual colonoscopy
  and virtual cystoscopy.
• A well-designed user interface enables the
  radiologist to interact dynamically with images
  of the "virtual" volume represented in computer
  memory.

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Anatomy of Urinary Bladder
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Staging of Bladder Cancer
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Diagnosis of Urinary Bladder Cancer

• Signs and Symptoms
• Urine Cytological Studies
• Cystoscopy and Biopsy
• Diagnostic Imaging
• IVP
• Ultrasound
• CT
• MRI

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Basis and Technical Issues of Virtual Imaging

• Volume data acquired from contiguous cross
  sectional images are transformed into set of
  voxels
• The voxels are positioned on a grid then
  Interpolation and segmentation are done
• Thresholding (the voxels or points with intensity
  values within an intensity range are selected )is
  used to display specific structures present in
  the volume data

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3D Rendering

• Surface Rendering
• Volume Rendering
• Classification
• Splatting
• Ray Casting

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Steps for Creating Virtual Cystoscopy

• Patient preparation and Image acquisition
• Image processing
• Segmentation.
• Fly through (creating virtual reality)
• Image analysis
• Image display

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Cystourethroscopy

• Indications
• Lower urinary tract disease
• Upper urinary tract
• The Instruments
• The rigid cystoscope
• Flexible fiberoptic cystoscope
• Video-cystourethroscopy

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Limitation of Cystoscope

• Invasive.
• Time-consuming.
• Expensive.
• The mucosa at the bladder neck and within bladder
  diverticula is not accessible.
• Need sedation.
• Susceptibility to infection or injury

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Complications and Sequela of Cystoscope

• Profuse bleeding.
• Damaged urethra.
• Perforated bladder.
• Urinary tract infection.
• Injured penis.
  
• scar tissue.

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• MR imaging was performed without external bladder
  filling or administration of IV contrast medium.
  No medications were given.
• Adequate distention of the bladder with urine was
  confirmed by coronal or sagittal MRI localizer
  sequences.
• The data were downloaded to an independent
  workstation (Advantage Windows 2.0 GE Medical
  Systems) equipped with software (Navigator GE
  Medical Systems) for interactive intraluminal
  navigation with a surface-rendering algorithm.

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Combined virtual and axial MR images for
detection of bladder lesions.
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• Female patient, 45 years old , presenting by
  hematuria and frequency.

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• Male patient, 65 years old, presenting by
  hematuria and dysuria.

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• Male patient, 74 years old, presenting by
  hematuria and frequency.

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• Male patient, 54 years old, presenting by
  hematuria and dysuria.

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• Male patient, 64 years old, had a history right
  nephrectomy two years ago for right renal pelvis
  transitional cell carcinoma, presenting by
  hematuria.

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• Male patient, 54 years old, presenting by
  hematuria and frequency.

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• Male patient, 64 years old, presenting by
  intermittent hematuria and frequency.

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• Male patient, 42 years old, presenting by
  hematuria and dysuria.

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The Advantages of Virtual Cystoscopy versus
Conventional Cystoscopy

• Non-invasive technique.
• No anesthesia .
• Accurate localization of a lesion .
• Accurate measurement of tumor size.
• Data of large number images in one image.
• More than view .
• Access to the anterior bladder wall or the lumen
  of a diverticulum .
• Detect lower ureteric extension.
• MR images assess extravesical extension.

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Our MR technique for virtual cystoscopy has
several advantages over other CT or MRI virtual
cystoscopy techniques including-

• No external bladder filling by air or carbon
  dioxide through bladder catheter.
• The examination in one position.
• There was no need for administration of IV
  contrast medium .
• No exposure to radiation .

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Limitation of MR- virtual cystoscopy

• Unable to depict flat lesions.
• Subtle mucosal color changes.
• Folding of the vesical mucosa.
• Can not determined the lesion nature.
• No visualization of urethral lumen.
• Not able to take biopsy.
• Metal prostheses or implants.
• Costly as screening method

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Summary and Conculsion
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On the basis of the results of this study and
other studies with conventional and virtual
cystoscope, we propose that virtual cystoscopy is
indicated when

• Conventional cystoscopy is difficult to perform,
  restricted in feasibility, unsatisfactory in
  interpretation, or contraindicated.
• Complementary examination for pateint with a
  non-resectable tumor to monitor treatment
  response.
• Virtual cystoscopy can be used complementary to
  conventional cystoscopy to enhance diagnostic
  performance

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• In the future, we expect improved detection rate
  and sensitivity for even very small tumors
  through continued development and advancement of
  hardware and software, with the possible use of
  virtual MR cystoscopy for screening and follow-up
  of bladder cancer after tumor resection, and in
  the clinical setting in which cystoscopy cannot
  be performed or is ineffective.

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Thank You