Angiography allows us to depict the vessels in the body after direct injection of contrast agent into the vessel under investigation. Usually we study the arteries, seldom the veins or lymphatics. Using fluoroscopy, the contrast agent shows us the contour of the vessel. Through this procedure, we can obtain selective high-resolution images of the vessels at various time points, including treatment of a narrowed vessel with dilatation.
Angiography is performed when a patient has vague complaints. B depicting the vessels, one can sometimes find the cause of the symptoms. Whether due to symptoms or previous images (e.g., ultrasound, CT, MRI), suspected changes in the vessels can be detected and treated at angiography. The veins of the lower extremities (i.e., pelvis, thigh, calf) or the kidneys and bowel, are the most commonly affected.
Most times, in therapeutic angiography a metallic mesh stent is placed into the vessel to keep it patent. The stents are not magnetic so they are MRI-compatible.
In order to prevent a new vascular blockage, you will be started on an anticoagulant, i.e., blood thinner, for at least a few months. If you develop symptoms localized to the target vessel, a CT or MRI will be done to check on the stent. Sometimes, another interventional procedure is necessary.
In principle, the risks for serious complications is very low. However, the risks depend on your pre-existing medical conditions, the region being treated, and the condition of your particular vessels.
The devices used can sometimes injure your vessels causing bleeding. Should this happen, the damage will be treated immediately, i.e., during the procedure. You may develop pain at the puncture site and/or allergic reaction to the contrast agent. Please see the information sheet information sheet for the complete list.
An aortic aneurysm is a widening of the aorta. Most aneurysms occur in the abdomen of the chest. However, aneurysms can develop in other vessels too.
As aneurysms usually have no symptoms, they are often found on routine imaging. The bigger the aneurysm, the more likely it is to tear and to cause life-threatening bleeding. If you develop symptoms that you think could be from an aneurysm, seek treatment quickly.
Aortic aneurysms usually arise in severe atherosclerosis which leads to a chronic inflammation in the artery. These inflammatory changes cause destruction of the connective tissue fibers and smooth muscle cells and weaken the vessel wall. Smoking, high blood pressure, high cholesterol level and obesity are the main risk factors. But age, gender and family history also play a role.
An aneurysm can be detected by and followed with abdominal ultrasound. CT is necessary to determine the exact size and shape of an aneurysm (Abb. 1). in exceptional cases, an MRI is necessary.
An alternative to surgery is to treat an aneurysm with metal mesh stents. In medical terminology, this is called endovascular grafting. This procedure is performed by the interventional radiologist with the assistance of an anesthesiologist and vascular surgeon.
In comparison to surgical repair (i.e., EVAR), endovascular grafting is gentle, conservative. Complication are less common with grafting. Furthermore, as grafting is performed through a small skin incision, healing is quicker and hospital stay is shorter.
The procedure is done under sedation. Increasingly, the aneurysm is reached through a small groin incision for the catheter. Then angiography is performed to depict the aneurysm precisely (Abb. 2). Under fluoroscopy, the stent is passed over a guidewire to enter the abdominal aorta. It is anchored in the aorta, below the renal arteries. After stent placement, angiography is repeated (Abb. 3), and later a CT is done to check/document that the stent’s position is satisfactory.
A few days after the procedure, CT angiography is done to check for stent position. If no complications are observed, follow-up CT is done once a year.
If there is a suspicion of tumor or infection, a biopsy will be done. Using a thin needle, a small specimen of tissue will be removed from the body and sent to the pathology lab for study. For a meaningful report, the specimen must contain sufficient tissue bearing evidence of the disease. It can be difficult to obtain a representative specimen through a small needle.
Using CT or ultrasound to direct the needle’s trajectory during the biopsy enormously increases the likelihood that the needle will enter the diseased tissue.
You will lie on the CT table or on a stretcher near the ultrasound machine. A few images will be taken to localize the diseased tissue and plan the best path for the needle to reach this tissue. Then the radiologist will precisely direct the needle towards the diseased tissue.
This minimally invasive procedure is performed using local anesthetic. The needle prick will feel like pressure; you will feel no pain. Typically, a short observation period follows the biopsy. Then you can go home.
Drainage includes the removal of pus from the soft tissues to prevent abscess formation. The doctor uses a CT or ultrasound to guide the catheter into the abscess so that the pus can then be drained off. Lastly, the abscess hole will be sterilized with saline solution.
The procedure occurs under local anesthesia. In most cases, antibiotics are given to heal the infection.
In the past decades, the gamut of cancer treatments, beyond surgery, chemo- and radiotherapy, has progressively increased. Various approaches exist to increase the effectiveness of the treatment on the tumor while minimizing the adverse effects. Particularly successful is immunomodulation therapy which has been trained to recognize the patient’s own immune system, thereby only fighting the cancer cells.
Another option is chemo- or radiotherapy directly to the affected vessels rather than to the entire body. Two methods used for treating liver tumors belong to this category, i.e., TACE (transarterial chemoembolization) and SIRT (selective internal radiotherapy). Anti-cancer radioactive substances are inserted into the liver via a very thin plastic tube. Thus, only cells in the affected liver segment die. Adverse effects are minimal.
Ablation has been proven effective in the treatment of liver tumors, less often in bone, kidney or lung tumors. Under CT guidance, the treatment probe and either heat (radiofrequency ablation and microwave ablation) or cold (cryoablation) are introduced into the tumor to cook or freeze the tumor, respectively. This is increasingly successful in reducing tumor burden, and under certain circumstances, also curing it. Should one of these procedures come into consideration, the interdisciplinary team (i.e., radiologists, oncologists, surgeons, and radiation therapists) will discuss it at Tumor Board.
The preparation for all of these procedures ist he same as for embolization.
The course of TACE is similar to that of embolization. SIRT is performed in conjunction with a nuclear medicine physician. Please see Selective internal Radiotherapy of liver tumors (SIRT).
Ablation is done under deep sedation or general anesthesia because the extreme heat or cold can cause pain. As an inpatient, an anesthesiologist will assess your fitness for sedation. The procedure itself will last 30 to 60 minutes.
Afterwards, a CT of the affected region will be performed to plan access, and to note nearby vessels and organs. If necessary, the CT will be done with contrast agent to better visualize the tumor. The probe and tumor will be visible throughout administration of heat or cold, i.e., 2-6 minutes. .
A compression device will be applied to the small wound. Afterwards, you must stay on bedrest for 24 hours. You may eat and drink on the evening of the procedure. As you may have pain or nausea for several hours after the procedure, please inform the nurses’ station if you would like pain medication.