Ultrasound & CT Scan
Improved technology and experience in interpretation have increased the accuracy and applicability of this noninvasive diagnostic modality.Ultrasonography can identify the thickness and echogenicity of the renal cortex, medulla, pyramids, and a distended urinary collecting system. Kidney size can be determined; a kidney less than 9 cm in length in an adult may indicate chronic renal disease. A difference in size of more than 1.5 cm between the two kidneys is observed in unilateral renal disease. Renal ultrasound is also performed to search for hydronephrosis and obstruction, to characterize renal mass lesions, to screen for autosomal dominant polycystic kidney disease, to evaluate the perirenal space, to localize the kidney for a percutaneous invasive procedure, and to assess postvoiding bladder residual urine volume.
Transrectal ultrasonography is used as an aid in performing transrectal ultrasound guided biopsies of the prostate gland to detect prostatic carcinoma.
Computed Tomography (CT) Scan
Computed tomography is one of the most useful and accurate means of evaluating intraabdominal pathology, and it has significantly enhanced evaluation of patients with renal, ureteral, bladder and prostate lesions.
Computed tomography (CT) uses x-ray and computer equipment to produce cross-sectional images of body tissues and organs. CT imaging is useful because it can show several types of tissue, such as lung, bone, soft tissue and blood vessels.
CT urography is a sophisticated, specialized radiological examination designed to evaluate the urinary tract (kidneys, ureters and bladder) using computed tomography (CT). This exam has been introduced to replace or complement the IVP (or excretory urogram). CT produces slices or cross-sectional images through the body enabling detailed evaluation of the internal organs. The CT urogram is optimally designed to specifically evaluate the urinary tract with the added advantage of visualizing all of the other abdominal and pelvic structures as well.
CT is required for further investigation of abnormalities detected by ultrasound or IVP. Although the routine study requires radiographic contrast administration, no contrast is necessary if the reason for the study is to demonstrate calcifications in the kidneys such as suspected stone disease. Since contrast is filtered by the glomeruli and concentrated in the tubules, there is enhancement of parenchymal tissue, making abnormalities such as cysts or neoplasms easily identified and allowing good visualization of renal vessels and ureters. CT is especially useful for evaluation of solid or cystic lesions in the kidney or the retroperitoneal space, particularly if the ultrasound results are suboptimal.
In some instances it has replaced other modalities such as renal cyst aspirations, angiography, and lymphangiography as a means of diagnosing and staging disease as well as of following patients after a diagnosis has been established and therapy instituted. Tumour extension, lymph node involvement, and metastases to other organs in the abdomen, chest, and brain can be demonstrated by CT scans.