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Cystinuria Support Network

Diagnosis

KUB

KUB stands for flat x-ray of the kidney, ureters and bladder. This is the standard form of x-ray. Cystine stones do not show up on these x-ray at all unless they are mixed with another ingredient such as calcium or oxalate or are very big. Their usefulness is doubtful however if it keeps the doctors happy…

Ultrasound

This is where a patient lies on their back, jelly is applied to their belly (often freezing cold) and a device similar to a computer mouse is run over the renal area. A patient may be asked to roll on their side and both belly and back are scanned. The operator may also try to scan the ureters and bladder for stones/obstructions. The kidney can be measured using this device. Stones show up as bright stars in the kidneys. Bright stars without shadows may not be stones but collections of crystals. It takes a very skilled operator or a cystinuric to spot the stones.

IVP/IVU

This is an x-ray which involves having a line inserted into a vein, dye is injected into the line a series of x-rays is taken. A patient may feel a warm sensation in various parts of their body. Sometimes a belt is used to slow down the flow. These x-rays can take anything from one to six hours. Cystinurics are often left in the x-ray room in between times. They are very boring. Sometimes this is the only way to see cystine stones.

Nephrostogram

This is an x-ray of the kidney and ureters where contrast is introduced through the nephrostomy tube, already in situ. If the kidney is obstructed this may be painful as the kidney is filled with contrast to its full capacity and causing dilation.

VCUG (Voiding cystourethrogram)

This is a particularly humiliating x-ray examination of the urethra and bladder. A patient is catheterized, contrast is introduced into the bladder and the catheter is clamped. A number of films are taken in various positions. The catheter is removed and the patient is encouraged to urinate on the table. A film is also taken whilst voiding. This is a particularly distressing examination and mild sedation is sometimes used.

Cat Scan/Spiral Cat Scan

Cat (Computer applied tomography or CT, computerized tomography) scans provide a three dimensional picture of the abdomen, kidneys, ureter, bladder, and surrounding tissues. It yields definitive information about tumors, cysts, masses, or obstructions. They do use a bowel prep the night before and no food after midnight.

It is performed in radiology and a contrast media is injected in the vein or given in the form of a fizzy drink to help visualize the images, then pictures are taken. Not all procedures use a contrast medium. Some cystinurics now insist that the CT scan is performed without contrast as they have found the contrast covers up the cystine stones.

This procedure is similar to an IVP except for the fact that the cystinuric is asked to lay on a moving table which moves them inside the machine. Some people find this uncomfortable or claustrophobic.

The cystinuric may be asked to remove their clothes and put on a gown. This can be avoided by wearing soft, loose clothing with no metal fastenings, no jewelry or bra. Then they lay down on the little table that moves them into the machine. It is open ended so it isn't usually a problem for claustrophobics. They hold their arms above their head, take in a DEEP breath and hold it for about 45 seconds. If they can't hold their breath that long they can VERY slowly let it out. The technicians are trying to avoid their organs moving to obscure the picture.

Some cystinurics say it feels like a line of static electricity running over their body, but it is not at all uncomfortable. The scan can diagnose stones which shop up "bright shiny" spots in the kidneys and other areas. It also will show other anatomy of the kidney. It can also show up "brush borders" which are areas of the kidney which have been hardened by the cystine.