Kidneys are responsible for filtering the blood and creating urine. Urine then drains from each kidney through the ureter to the bladder, which then empties through the urethra. Many different diseases can affect each of these structures, such as stones and tumors. Using state of the art imaging equipment and minimally invasive techniques, the Interventional Radiologists at Houston Radiology can help urologists diagnose and manage these diseases, preserving kidney function and quality of life.
Nephrostomy/Nephroureteral stent placement/revision/removal
The ureter drains urine from the kidney to the bladder. It can be blocked by many diseases, but it is most commonly blocked by either a stone or tumor. This blockage can cause urine to build up within the kidney, resulting in pain, infection, and kidney dysfunction.
Blockages can often be treated by urologists who can place a draining tube inside the ureter with a small scope advanced from the urethra into the bladder or by surgically bypassing the blockage. In other cases, however, interventional radiologists can treat a blockage by placing a drain through the patient’s back into the kidney collecting system (called a nephrostomy tube) or through the patient’s back, kidney collecting system, and ureter into the bladder (called a nephroureteral tube). These tubes may be used to treat the blockage in the short and long term and may also help urologists perform subsequent procedures to break up/remove stones.
Under ultrasound and x-ray guidance, a needle is advanced across the back and kidney into the kidney collecting system. Contrast is injected to look at the collecting system/ureter and evaluate the location of the blockage. Then, a wire is advanced through the needle into the collecting system, the needle is exchanged for a catheter, and the wire is removed. This catheter is left is in place to drain urine.
The procedure has a moderate risk of bleeding, infection, and damage to nearby organs. If possible, patients should refrain from eating and drinking for 6 hours prior to the procedure and will be given medications to help them relax (i.e. moderate sedation). The procedure is typically reserved for inpatients, who will then remain in the hospital overnight after their procedure.
Prostate artery embolization
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One way to treat tumors (particularly renal arteriovenous malformations and angiomyolipomas) in the kidney is to find the blood vessels that supply the tumor and block them off from the inside with plastic beads and/or medications.
First, using ultrasound and x-ray guidance, a small needle is used to enter the artery of the leg or wrist. Then, small catheters and wires are used to find the arteries that supply the kidney and tumor. Finally, chemotherapy and plastic beads are slowly injected to block blood flow to the tumor and cause it to shrink/die. In certain cases, the patient may then go on to have a tumor ablation (see above) or surgery.
The procedure has a low risk of bleeding, infection, and damage to nearby organs. Patients should refrain from eating and drinking for at least 6 hours prior to the procedure so that we may give them medications to help them relax (moderate sedation). We typically perform for the procedure for outpatients, who will then remain in the hospital overnight.
Suprapubic catheter placement
The urethra is the tube that drains the bladder to the outside world. Many different things can block this tube, including benign prostatic hyperplasia (a non-cancerous enlargement of the prostate) and cancer. In the short-term, doctors can usually treat this difficulty by placing a tube through the urethra into the bladder. Unfortunately, if the catheter remains in place for too much time, it can stop working or even hurt the patient’s pelvic organs. Interventional Radiologists at HRA can help patients and physicians by placing tubes directly through the belly wall into the bladder allowing an alternate pathway for urine to drain.
Under ultrasound guidance the bladder is located. Overlying soft tissues are numbed with a tiny needly. Then, a small needle is advanced through the overlying abdominal wall into the bladder. A wire is advanced through the needle into the bladder. The needle is then exchanged over the wire for a drainage catheter. Finally, the wire is removed, and the catheter is secured to the skin.
The procedure has a mild to moderate risk of bleeding, infection, and damage to nearby organs. Patients should refrain from eating and drinking for 6 hours prior to the procedure in order that they may receive medications to relax (i.e. moderate sedation). This procedure can be performed for both inpatients and outpatients, who can then return to their room/home after afterwards.
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Doctors performing Urologic Interventions
Patrick Marcin, MD
Interventional Radiology (IR)