urinary system

Question 1

kidneys

Answer 1

• located in the posterior aspect of the upper abdomen
• they are posterior and inferior to the liver
• due to the presence of the liver, the right kidney is usually more inferior than the left
• in relation to the left kidney, the spleen sits laterally and superiorly, and the pancreas is a long tail like organ that sits anteriorly
• the large and small bowels sit anteriorly to the kidneys
• the posterior aspect of the kidneys are in close proximity to the 11th and 12th ribs

Question 2

nephrons

Answer 2

• lie between the medulla and cortex of the kidney
  distal convoluted tubule
• connects the loop of henle to the collecting duct
• controls electrolyte levels including sodium, potassium nd calcium
• also regulated pH levels
  collecting duct
• the final part of the nephron that connects to the renal calyx
• also responsible for electrolyte and fluid balance
  loop of henle
• connects the proximal and distal convoluted tubules
• over the descending and ascending limbs, water and sodium are reabsorbed into the body, and urea is retained
  glomerulus
• bed of small capillary vessels
• filter plasma from the blood to create glomerular filtrate
• filters out proteins and red/white blood cells
  bowman’s capsule
• cute like sac that covers the glomerulus
• collects filtered plasma from the glomerulus to send into the tubule system
  proximal convoluted tubule
• connects the bowman’s capsule to the loop of henle
• initiates the absorption process

Question 3

CT Urogram

Answer 3

1. non contrast phase
   - used for detecting any stones or gross anatomy
   - also used as a control / reference image
   - can detect any fresh blood without contrast obscuration
2. renal cortical phase
   - scanned at around 30 seconds post injection
   - kidney not yet fully opacified
   - contrast not yet reached urinary tract
   - helpful for subcategorising carcinomas
3. nephrogenic phase
   - scanned at 100 seconds post injection
   - maximum kidney enhancement
   - contrast hs still not reached the urinary tract
   - used for detecting vascular components of masses
4. excretory phase
   - scanned at between 5 and 10 minutes post injection
   - contrast should be in the ureters and bladder so any obstruction should be visible in this phase
   - kidney opacification greatly reduced

Question 4

ultrasound

Answer 4

• scanned both as part of a urinary / abdominal assessment, but also as a dedicated bladder scan often conducted on wards mainly to assess emptying / volume
• excellent visualisation of he convolute, medulla, renal pelvis and bladder
• ureters difficult to visualise unless dilated
• indication include renal stones, ureteral obstruction, bladder distension, ?renal carcinoma / massess in renal artery / vein disorders

Question 5

hydronephrosis

Answer 5

• if the urinary tract gets obstructed, often by a stone, this can leas to dilation of the proximal system
• most often the renal pelvis distends as stones pass into the ureters and get stuck
• visible as a large hypo echoic dilation of the medullary area of ultrasound, and a radiolucent collection of CT unless contrast is administered

Question 6

renal cell carcinoma

Answer 6

• mixed appearance on ultrasound
• common symptoms include haematuria, flank plain, palpable mass
• however ultrasound is less sensitive than CT / MRI and cannot stage the cancer
• contrast enhances US (CEUS) can improve visualisation and identify vascularity

Question 7

CT KUB

Answer 7

• usually a low dose protocol is used by reading mA and putch
• scan range: adrenal glands to bladder, no need to include diaphragm or ischium
• can be difficult to visualise kidneys, so some scan caudo > cranial and stop the scan once the kidneys are passed
• mainly utilised for visualising stones, as without contrast ureters are difficult to see

Question 8

xray

Answer 8

• in developed health systems has been replaced by US/CT for investigating the renal tract
• can detect some types of kidney stones, but unable to visualise ureters, bladder or kidney without introducing contrast
• poor sensitivity / specificity for detecting renal stones

Question 9

fluoroscopy

Answer 9

• like X-ray, it is very difficult to visualise the urinary system without contrast
• primarily used a guidance for kidney intervention including; nephrostomy, ureic stent and urodynamic studies