VIII. The radiological diagnosis of kidney and urinary tract

In the diagnostics of the diseases of the kidney and urinary tract, the diagnostic imaging modalities play an excellent role.

Examination procedures and symptomatology

• Plain radiograph: This is suitable for the visualization of pathological calcifications (stone, inflammation or nephrosclerosis) or the collection of gas/air (abscess).
• Intravenous urography: The contrast material, which is excreted through kidney, is administered intravenously, and in the early phase (nephrographic) depicts the parenchyma faintly, then fills the excretory system, ureter and bladder. On i.v. urography excretory system deformities (narrowing, dilatation, dislocation or obstruction), and diseases causing filling defects (stone or tumor) can be detected. This procedure may be used only with a functionally intact kidney.
• Anterograde, or retrograde pyelography: In case of non-functioning kidney or obstructed collecting system the visualization is done either by direct percutaneous punction or retrograde filling of the pyelon through a catheter inserted via urethra. This procedure can help reveal changes in the excretory system.
• Ultrasound (US) examination:
• Transabdominal US (+ Doppler): This is an excellent method of choice and is suitable for visualization of focal changes in the renal parenchyma, diffuse reflective changes or circulatory discrepancies. The ureters are poorly visualized.
• Transrectal/transvesical US: This permits visualization of lesions of the bladder wall. The use of US guided interventions are used for diagnostic or therapeutic purposes.
• Computer tomography (CT): This is an excellent method for the visualization of inflammatory and neoplastic lesions of the kidneys and the surrounding environment. CT affords help in percutaneous interventions and is essential for the staging/categorization of the tumors.
• Magnetic resonance imaging (MRI): This is used as an accessory examination adding to the information already obtained from a CT scan, the nature of the focal lesion being ascertained from the aspect of the status of the vessels.
• Angiography: Angiography is indicated for diagnostic purposes only in special cases (reno-vascular hypertension), but it plays an important role in guided transvascular interventions.

Diseases and their radiological examination

• As a general rule US is the first method of choice; the further steps are planned on the basis of the clinical picture and the results of US examination.
• "Medical" renal diseases (glomerulonephritis or nephrosis syndrome, etc.): The diagnostic imaging procedures are of little significance for deciding the size of the kidney; they are rather used for follow-up studies to establish the progression of parenchymal destruction, for which US itself is sufficient.
• Pyelonephritis: In acute cases, the clinical picture is usually diagnostic. The role of imaging procedures is for clarification of the etiology (obstruction) or complications (abscess, carbuncle or rupture). Together with US, CT may be required; rarely contrast-enhanced visualization of the excretory system is also performed. Parenchymal destruction in a chronic disease process can be assessed with the help of US. In TBC, besides US, i.v. urography is indicated.
• Urethra obstruction (stone): When the excretory system is dilated, the site and cause of the obstruction can in most cases be clarified by US. If the US examination does not lead to a definitive result, contrast-enhanced visualization of the excretory system should becarried out.
• Renal rupture "(spontaneous", or traumatic): The localization and extent of the injury can be definitely established by US. In patients who are difficult to examine or who have widespread vascular injuries, CT or angiography may be required.
• Renovascular hypertension: The vascular stenosis of renal arteries can be seen with Doppler US, angiography may be needed, with the help of which an identified arterial stenosis can be corrected.
• Space occupying lesions of the kidney: A typical renal cyst can be diagnosed by US, typical angiomyolipoma can be demonstrated on the basis of its fat content, with CT, while solid or mixed focal lesions should be considered to be malignant. In doubtful cases, MR helps in clarification of the composition of the lesion. Tumors of the excretory system are revealed by contrast enhancement.
• Diseases of the ureter (stone, inflammation, tumor and external compression/dislocation): These are visualized by contrast enhancement (i.v. or retro/anterograde filling). The changes in the surrounding environment are shown by CT.
• Diseases of the urinary bladder: Lesions involving the internal bladder membrane are diagnosed by cystoscopy. The endoluminal bodies (stone or tumor) or bladder deformities and injuries are best observed by contrast-enhanced examination. The bladder wall and involvement of the surrounding environment are depicted by US/CT/MR imaging.

List of the pictures:

EXAMINATION PROCEDURES

Normal kidney
Normal kidney
Normal kidney
Normal kidney
Normal kidney

DISEASES OF THE KIDNEY

Hypoplastic kidney
Supernumerary kidney
Kidney abscess
Nephrolithiasis
Nephrolithiasis
Nephrolithiasis
Traumatic rupture of the kidney
Traumatic rupture of the kidney
Ruptured kidney
Ruptured kidney
Polycystic kidney
Angiomyolipoma
Angiomyolipoma
Hypernephroma
Hypernephroma
Hypernephroma
Hypernephroma

DISEASES OF THE URINARY BLADDER

Bladder tumor
Bladder tumor
Bladder tumor