tailieunhanh - Ebook Diagnostic imaging (7/E): Part 2

(BQ) Part 2 book “Diagnostic imaging” has contents: Urinary tract, female genital tract, peritoneal cavity and retroperitoneum, bones, joints, skeletal trauma, orbits, head and neck, vascular and interventional radiology, spine. | 8 Urinary Tract The four basic examinations of the urinary tract are ul­ trasound, intravenous urography (IVU), computed tom­ ography (CT) and radionuclide examinations. Magnetic resonance imaging (MRI), arteriography and studies re­ quiring catheterization or direct puncture of the collecting systems are limited to selected patients. Fluorodeoxyglu­ cose positron emission tomography (FDG-PET)/CT is still under investigation as an imaging tool in the urinary tract, as there are currently several limitations due to excretion of the tracer in the renal tract and poor uptake in many urological malignancies. Ultrasound, CT and MRI are essentially used for ana­ tomical information; the functional information they provide is limited. The converse is true of radionuclide examinations where functional information is paramount. IVU provides both functional and anatomical information. • To diagnose hydronephrosis, renal tumours, abscesses and cysts including polycystic disease. • To assess and follow-up renal size and scarring in chil­ dren with urinary tract infections. • To assess the bladder and prostate. Normal renal ultrasound At ultrasound, the kidneys should be smooth in outline. The parenchyma surrounds a central echo-dense region, known as the central echo complex (the renal sinus), con­ sisting of the pelvicaliceal system, together with the sur­ rounding fat and renal blood vessels (Fig. ). In most instances, the normal pelvicaliceal system is not visible within the renal sinus. The renal cortex generates homo­ geneous echoes that are of equal reflectivity or less reflec­ tive than those of the adjacent liver or spleen, and the renal pyramids are seen as triangular hypoechoic areas adjacent to the renal sinus. During the first 2 months of life, cortical echoes are relatively more prominent and the renal pyramids are disproportionately large and strikingly hypoechoic. The normal adult renal length, measured by ultrasound, is 9–12 cm. Renal length varies with .