Opening Round
Case 1
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1. What treatment would you recommend for this 32-year-old woman with fever, flank pain, leukocytosis, and urinalysis consistent with urinary tract infection?
2. Unilateral or bilateral?
3. When should this procedure be performed?
4. What is the most common cause of this diagnosis?
ANSWERS: CASE 1
Pyonephrosis
1. Percutaneous nephrostomy tube insertion.
2. Bilateral.
3. Urgently.
4. Urinary tract stones.
Reference
Watson, R.A.; Esposito, M.; Richter, F., Percutaneous nephrostomy as adjunct management in advanced upper urinary tract infection, Urology 5 4 (1999) 234–239.
Cross-Reference
Comment
The CT examination demonstrates bilateral hydronephrosis. Although percutaneous nephrostomy tubes can be inserted electively for relief of urinary obstruction, clinical signs of infection are concerning for pyonephrosis: infected urine within the obstructed urinary collecting system. Such patients are at risk for sepsis, and percutaneous nephrostomy should be performed urgently. In the patient who already exhibits signs of sepsis, percutaneous nephrostomy can be life-saving and must be performed emergently.
Percutaneous nephrostomy tubes can be placed using a variety of imaging guidance techniques. If contrast material is already present from an existing study or if an existing ureteral stent or radiopaque renal calculus is present, then fluoroscopic guidance alone may be sufficient. Otherwise, ultrasound- or CT-guided puncture of a posterior calyx can be performed (one-pass method). Alternatively, if a dilated posterior calyx is not clearly visible, then the renal pelvis can be punctured with a 22-gauge needle. A small amount of contrast and air are injected to opacify a posterior calyx, which is then definitively punctured using an 18-gauge needle under fluoroscopic guidance (two-pass method).
Although any cause of urinary tract obstruction can lead to hydronephrosis or pyonephrosis, more than 50% of cases result from urinary tract calculi. Another common cause is ureteral compression by a pelvic mass lesion. Definitive removal of the obstructing agent should be deferred to a time when the patient’s infection has resolved, because excessive manipulation can precipitate sepsis.
Notes
Case 2
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1. What abnormality is seen in the first image?
2. What is the most likely etiology?
3. Would you describe this as an acute event or a chronic event?
4. How is blood reaching the lower extremities in this patient?
ANSWERS: CASE 2
Abdominal Aortic Occlusion (Leriche’s Syndrome)
1. Occlusion of the infrarenal abdominal aorta with enlarged lumbar collaterals.
2. Atherosclerosis.
3. This most likely represents thrombosis at the site of a chronic stenosis.
4. Superior mesenteric artery to inferior mesenteric artery via an enlarged marginal artery of Drummond (second image), to the internal iliac arterial system and finally to the common femoral arteries.
Reference
Bosch, J.L.; Huninck, M.C., Meta-analysis of the results of percutaneous transluminal angioplasty and stent placement for aorto-iliac occlusive disease, Radiology 204 (1997) 87–96.
Cross-Reference
Comment
Occlusion of the abdominal aorta can result from a variety of causes including trauma, thromboembolism, or iatrogenic dissection. In this case, thrombosis is superimposed on chronic atherosclerotic stenosis, a condition known as Leriche’s syndrome. In these patients, symptoms of ischemia might not appear until occlusion is imminent, and some patients present after the vessel has occluded. The classic symptoms of Leriche’s syndrome are seen in men and include hip and buttock claudication, absent femoral pulses, impotence (due to limitation of blood flow into the internal iliac artery territories), and cool lower extremities.
The slow progression of the atherosclerotic occlusion allows the development of large intercostal, lumbar and epigastric collaterals that provide flow to the iliac arteries and lower-extremity vessels. The treatment of choice for Leriche’s syndrome is surgical bypass graft placement; in this case, an aorto-bifemoral graft would be appropriate. In patients who are not surgical candidates, endoluminal recanalization and stenting of the occluded aorta and iliac arteries can be performed.
Notes
Case 3
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1. What is the most likely diagnosis?
2. Does this represent a vascular ring?
3. Does this finding usually indicate the presence of congenital heart disease?
4. Does this finding typically cause airway compression?
ANSWERS: CASE 3
Variant Anatomy: Right-Sided Aortic Arch
1. Right aortic arch with aberrant left subclavian artery.
2. Yes.
3. No.
4. No.
References
Franquet, T.; Erasmus, J.J.; Gimenez, A., The retrotracheal space: Normal anatomic and pathologic appearances, Radiographics 22 (2002) S231–S246.
Donnelly, L.F.; Fleck, R.J.; Pacharn, P.; et al., Aberrant subclavian arteries: Cross-sectional imaging findings in infants and children referred for evaluation of extrinsic airway compression, Am J Roentgenol. 178 (2002) 1269–1274.
Cross-Reference
Comment
A right-sided aortic arch with aberrant left subclavian artery occurs in 0.05% to 0.10% of the population. The aortic arch passes over the right mainstem bronchus and descends to the right of the esophagus and trachea. The left subclavian artery arises as the last branch, often from a diverticulum of Kommerell, as in this case, and passes behind the trachea and esophagus to supply the left arm. Symptoms of respiratory and esophageal compression are seen in only 5%. Only 10% of patients have associated congenital heart disease, most commonly tetralogy of Fallot.
Right aortic arch can also be seen with mirror-image branching. In this situation, the aortic branch vessels in order are the left brachiocephalic artery, right common carotid artery, and right subclavian artery. More than 98% of these patients have cyanotic congenital heart disease, most commonly tetralogy of Fallot.
Notes
Case 4
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1. What vessel does this dialysis catheter traverse just before reaching the heart?
2. How does blood typically reach the right atrium in this anatomic variant?
3. Is there an association with congenital heart disease?
4. What anatomic variant is in the differential diagnosis?
ANSWERS: CASE 4
Variant Anatomy: Left Superior Vena Cava
1. Left superior vena cava.
2. Via the coronary sinus.
3. Yes.
4. Duplicated superior vena cava.
Reference
Minniti, S.; Visentini, S.; Procacci, C., Congenital anomalies of the venae cavae: Embryological origin, imaging features and report of three new variants, Eur Radiol. 12 (2002) 2040–2055.
Cross-Reference
Comment
A left superior vena cava results from persistence of the left anterior cardinal vein. This usually occurs in association with congenital heart disease, although it occurs rarely as an isolated abnormality associated with situs inversus. Typically, the left superior vena cava drains to the right atrium via the coronary sinus, but occasionally it drains directly into the left atrium.
Duplication of the superior vena cava is more common and is even more often associated with congenital heart disease. It can be associated with anomalous pulmonary venous return. Similar to the isolated left superior vena cava, the left moiety typically drains into the coronary sinus.
Notes
Case 5
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1. What type of examination is depicted above and how was it performed?
2. What is the primary abnormality in the right leg?
3. What surgical treatment can be used for this problem?
4. Would endovascular stent placement be a good alternative to surgery?
ANSWERS: CASE 5
Occluded Superficial Femoral Artery
1. Bilateral lower-extremity digital subtraction arteriogram. A catheter has been placed via the right common femoral artery (CFA) into the aorta or into the right iliac artery.
2. Right superficial femoral artery (SFA) occlusion with popliteal reconstitution.
3. Femoropopliteal bypass graft placement.
4. Self-expanding nitinol stents may be used for treating this condition, but they should be reserved for patients who are not candidates for surgery.
Reference
Hunink, M.; Wong, J.; Donaldson; et al., Revascularization for femoropopliteal disease: A decision and cost-effectiveness analysis, JAMA. 274 (1995) 165–171.
Cross-Reference
Comment
The SFA represents an extremely common site of atherosclerotic disease. Stenotic lesions in this vessel are most commonly observed at the level of the adductor (Hunter’s) canal. These lesions are a common cause of calf claudication and can contribute (in the presence of other lesions) to rest pain and limb-threatening ischemia. Progressive SFA stenosis often leads to complete SFA occlusion.
When describing a lesion in the SFA, several observations are important to make: (1) The status of the ipsilateral CFA is important because this vessel nearly always represents the source vessel for a therapeutic bypass graft; (2) The point at which the distal circulation reconstitutes, as well as its continuity with pedal flow, determines the distal anastomotic site of the bypass graft; (3) The status of the ipsilateral profunda femoral artery often determines the clinical status of the limb, because this vessel provides the source for the collaterals that reconstitute the distal circulation.
The standard treatment of isolated SFA occlusion with popliteal reconstitution is femoropopliteal bypass graft placement. This procedure has a 5-year patency of 50% to 80%, depending on whether the distal anastomosis is placed above or below the knee and depending on the number and quality of patent runoff vessels. Catheter-directed thrombolysis with subsequent angioplasty and stenting can be used to recanalize native SFA occlusions, but patency rates following this procedure are less than those of surgical therapy.
Case 6
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1. What vessel is selectively injected?
2. What is the abnormality?
3. When is treatment recommended?
4. What treatment methods can be used?
ANSWERS: CASE 6
Splenic Artery Aneurysm
1. Celiac artery.
2. Splenic artery aneurysm.
3. Treatment is recommended when the aneurysm is large (>2.5cm), symptomatic, or rapidly expanding and in women who are or might become pregnant.
4. Transcatheter embolization (preferred in most cases) or surgical resection.
Reference
Stanley, J.C., Mesenteric arterial occlusive and aneurysmal disease, Cardiol Clin. 20 (2002) 611–622.
Cross-Reference
Comment
The splenic artery is the most common site of visceral artery aneurysms, followed by the hepatic artery. Splenic artery aneurysms are more common in women than men. The most common etiology is medial degeneration with superimposed atherosclerosis. There appears to be some relationship to pregnancy because the majority of women who have splenic artery aneurysms have had at least two pregnancies, and pregnancy is associated with an increased risk of rupture. Other causes include trauma, pancreatitis, infection, congenital portal hypertension, collagen vascular disease, hypersplenism, fibromuscular dysplasia, and vasculitis.
Many aneurysms are discovered incidentally on cross-sectional imaging. The main risk is aneurysm rupture, which carries a high mortality. These patients typically present with abdominal pain and/or hypotension. Nevertheless, less than 10% of aneurysms rupture, and the majority of ruptures are associated with pregnancy. Therefore, treatment is not recommended for all unruptured aneurysms.
Treatment is directed at eliminating flow into the aneurysm sac. Transcatheter embolization is the preferred treatment, and coils are the most commonly used agent. It is important to embolize from distal to proximal across the aneurysm neck to prevent retrograde flow into the aneurysm from collateral vessels filling the distal splenic artery. Splenic infarction or abscess formation is rare owing to collateral flow to the spleen. Splenic artery aneurysms can be treated surgically by removing the spleen and aneurysm or by ligating the artery proximal and distal to the aneurysm.
Case 7
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1. What is the main angiographic finding?
2. Is this pathologic?
3. What vascular beds most commonly demonstrate this finding?
4. What is the likely explanation?
ANSWERS: CASE 7
Normal Finding: Standing Waves
1. A regular corrugated appearance of the arteries, known as standing waves.
2. No.
3. The extremity arteries and mesenteric vessels.
4. Flow and pressure changes during contrast injection into a high-resistance vascular bed.
Reference
Reuter, S.R.; Redman, H.C.; Cho, K.J., Vascular diseases, In: Gastrointestinal Angiography3rd ed. (1986) Saunders, Philadelphia, pp. 120–121.
Cross-Reference
Comment
Standing waves are occasionally observed during arteriography of the extremities or mesenteric vessels. Appearing as regular alternating areas of constriction, they likely result from focal, circular vasoconstriction. Various hypotheses exist to explain this benign finding. All center on changes in flow and pressure resulting from injection of contrast media.
Case 8
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1. What is the likely diagnosis?
2. Is this disorder more common in men or women?
3. Name three conditions that this disorder can be associated with.
4. Name three long-term complications of this disorder.
ANSWERS: CASE 8
Sclerosing Cholangitis
1. Sclerosing cholangitis.
2. Men (70% of cases).
3. Inflammatory bowel disease, pancreatitis, mediastinal or retroperitoneal fibrosis.
4. Acute cholangitis episodes, biliary cirrhosis, cholangiocarcinoma.
Reference
Bader, T.R.; Beavers, K.L.; Semelka, R.C., MR imaging features of primary sclerosing cholangitis: Patterns of cirrhosis in relationship to clinical severity of disease, Radiology 226 (2003) 675–685.
Cross-Reference
Comment
Sclerosing cholangitis is an insidious progressive disease in which chronic inflammation and obliterative fibrosis affect the intrahepatic and extrahepatic biliary ductal system. Patients often present with chronic or intermittent obstructive jaundice, abdominal pain, fatigue, and/or fever. The hallmark cholangiographic findings of sclerosing cholangitis include multifocal strictures, saccular outpouchings and areas of dilation, a beaded appearance of the biliary ductal system, and/or a pruned-tree appearance of the biliary system. The common bile duct is almost always involved. The differential diagnosis of these findings includes multifocal cholangiocarcinoma and primary biliary cirrhosis.
Sclerosing cholangitis can occur as a primary idiopathic disorder or in association with other inflammatory conditions, including ulcerative colitis, Crohn’s disease, pancreatitis, retroperitoneal fibrosis, or mediastinal fibrosis. The dreaded long-term sequelae of this disorder are biliary cirrhosis with portal hypertension, and cholangiocarcinoma.
Medical management of primary sclerosing cholangitis is not particularly effective. Percutaneous biliary drainage or hepaticojejunostomy can provide palliation to carefully selected patients with appropriate anatomy, but the only truly effective treatment for this disorder is liver transplantation.
Case 9
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1. What type of study has been performed?
2. What is the diagnosis?
3. How long have the patient’s symptoms likely been present?
4. What treatment options might be considered?
ANSWERS: CASE 9
Acute Deep Vein Thrombosis
1. Lower-extremity venogram.
2. Acute femoral deep vein thrombosis (DVT).
3. Less than 2 weeks.
4. Anticoagulation is the traditional standard of care. Selected patients with acute iliofemoral DVT may be treated with catheter-directed thrombolysis or surgical thrombectomy. Elastic compression stockings should be worn for at least 2 years to prevent post-thrombotic syndrome. Patients who have contraindications to anticoagulation should undergo filter placement in the inferior vena cava for prophylaxis of pulmonary embolism.
Reference
Society of Interventional Radiology: Society of Interventional Radiology position statement Vedantham, S.; Millward, S.F.; Cardella, J.F.; et al., Treatment of acute iliofemoral deep vein thrombosis with use of adjunctive catheter-directed intrathrombus thrombolysis, J Vasc Interv Radiol. 17 (4) (2006) 613–616.
Cross-Reference
Comment
Lower-extremity DVT is a significant cause of morbidity and long-term disability. The immediate complications of DVT can include pulmonary embolism and limb-threatening phlegmasia. In the long term, a large fraction of DVT patients experience post-thrombotic symptoms, which include limb heaviness and aching, ambulatory edema, venous claudication, and lower extremity ulcerations.
The diagnosis of DVT in the femoropopliteal veins can be made with high accuracy using duplex ultrasound. In contrast, lower-extremity venography, the gold standard for the diagnosis of DVT, is only infrequently required for diagnosis. Venography is more often used to evaluate for DVT in the iliac venous system, which is often not well visualized by ultrasound. Venographic findings of acute (< 2 weeks) DVT typically include globular filling defects within a vein, abrupt occlusion of the vein, and/or dilation of the distal venous system. In this case, globular elongated filling defects are present within the femoral vein.
The standard treatment for patients with DVT is anticoagulation using low-molecular-weight or unfractionated heparin followed by coumadin for at least 3 months in most instances.
Patients with iliofemoral DVT have a particularly high risk of developing a severe form of post-thrombotic syndrome. For this reason, selected patients with acute iliofemoral DVT are treated with catheter-directed thrombolysis or surgical venous thrombectomy.
Notes
Case 10
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1. What abnormality is present?
2. What is the likely etiology of this abnormality?
3. How can patients with this problem be treated?
4. What imaging modality is best used for follow-up after treatment?
ANSWERS: CASE 10
Tibial Artery Pseudoaneurysm
1. Large saccular pseudoaneurysm of the anterior tibial artery.
2. Trauma, iatrogenic vascular injury, or infection.
3. Surgical repair of the vessel is usually employed. In select cases where the vessel does not provide significant arterial supply to the foot, angiographic embolization may be performed.
4. Duplex ultrasound.
Reference
Wolford, H.; Peterson, S.L.; Ray, C.; et al., Delayed arteriovenous fistula and pseudoaneurysm after an open tibial fracture successfully managed with selective angiographic embolization, J Trauma. 51 (2001) 781–783.
Cross-Reference
Comment
Peripheral pseudoaneurysms of medium-sized vessels most commonly occur in the setting of trauma. In this case, the trauma was probably caused by Fogarty catheter embolectomy of the tibial arteries following revision of a thrombosed femoropopliteal bypass graft (not shown). Although mycotic aneurysm is rare, the possibility should be considered when saccular or irregular aneurysms are seen in the periphery.
Although duplex ultrasound can diagnose and localize the pseudoaneurysm, arteriography is important in planning appropriate therapy. It is important to determine the exact location of the entry into the pseudoaneurysm and to completely evaluate the arterial runoff to the extremity. When the injured vessel still makes a significant contribution to perfusion of the lower extremity, surgical repair of the vessel or ligation with distal bypass is clearly indicated. In select instances when this is not the case, arterial embolization may be undertaken. In this instance, it is important to place coils within the artery both proximal and distal to the origin of the pseudoaneurysm.
Notes
Case 11
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1. What type of examination is depicted?
2. What symptoms are likely to be present?
3. What abnormality is seen on the image?
4. How might this problem be treated?
ANSWERS: CASE 11
Dialysis Graft Stenoses
1. Dialysis fistulogram.
2. Low flows or high recirculation during dialysis.
3. Three stenoses are present: a tight stenosis at the venous anastomosis of the graft and two mild stenoses within the graft.
4. Angioplasty of the stenoses, or surgical graft revision.
Reference
National Kidney Foundation, Guidelines for vascular access, In: Kidney Disease Outcomes Quality Initiative Clinical Practice Guidelines (2000) National Kidney Foundation, New York.
Cross-Reference
Comment
Hemodialysis can be performed from a variety of access routes: (1) A native fistula can be created between an extremity artery—usually a radial artery or brachial artery—and an adjacent vein; (2) A prosthetic graft—usually polytetrafluoroethylene—can be placed to attach a parent artery to an outflow vein; (3) A dialysis access catheter may be placed from a suitable central vein, preferably an internal jugular vein.
When a native fistula or prosthetic graft is used, suboptimal dialysis can occur due to formation of stenotic lesions somewhere in the vascular access circuit. The venous anastomosis of the graft is by far the most common site of stenosis in patients with prosthetic grafts, as in this case. However, suboptimal dialysis can also result from flow-limiting stenoses within the graft, within the outflow veins draining the graft, within the central venous system, at the arterial anastomosis, or even in the parent artery. Such lesions, in addition to causing suboptimal dialysis, ultimately lead to graft thrombosis in the majority of cases.
Improved duration of graft patency and improved dialysis quality can be achieved via successful treatment of stenotic lesions. This can be achieved surgically or via percutaneous transluminal angioplasty. The mean graft patency following angioplasty of a venous stenosis of a patent graft is approximately 6 months, but repeat angioplasty can often delay graft replacement for several years.
Notes
Case 12
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1. On an anteroposterior view of an angiogram, name the three tibial runoff arteries from lateral to medial.
2. Do most patients have a true trifurcation of the popliteal artery?
3. Which vessel continues into the foot as the dorsalis pedis artery?
4. Which vessel normally terminates above the ankle level?
ANSWERS: CASE 12
Normal Tibial Artery Anatomy
1. Anterior tibial artery, peroneal artery, and posterior tibial artery.
2. No.
3. Anterior tibial artery.
4. Peroneal artery.
Reference
Toussarkissian, B.; Mejia, A.; Smilanich, R.P., Noninvasive localization of infrainguinal arterial occlusive disease in diabetics, Ann Vasc Surg. 13 (2001) 714–721.
Cross-Reference
Comment
The popliteal artery begins distal to the adductor canal and passes through the popliteal fossa between the heads of the gastrocnemius muscle. At its terminal aspect it typically bifurcates into the anterior tibial artery and tibioperoneal trunk. After 2 to 3cm, the tibioperoneal trunk in turn bifurcates into the peroneal and posterior tibial arteries. A true trifurcation of the popliteal artery is only present in a minority of patients.
In the normal patient, the anterior tibial artery continues across the ankle as the dorsalis pedis artery; the posterior tibial artery passes behind the medial malleolus into the foot, where it divides into the lateral and medial plantar arteries. These vessels then anastomose through dorsal and plantar arches within the foot. The peroneal artery runs in the interosseous membrane and typically gives off terminal branches proximal to the ankle that anastomose with branches from the posterior tibial artery and anterior tibial artery.
Notes
Case 13
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1. What angiographic abnormality is depicted?
2. What symptoms are likely being experienced by the patient?
3. Does this abnormality occur more commonly on the left or the right?
4. What is the most common etiology of this abnormality?
ANSWERS: CASE 13
Subclavian Steal Syndrome
1. Subclavian steal syndrome.
2. Symptoms of vertebrobasilar insufficiency or, less likely, symptoms of brachial insufficiency.
3. Left (3:1 ratio).
4. Atherosclerosis.
Reference
Taylor, C.L.; Selman, W.R.; Ratcheson, R.A., Steal affecting the central nervous system, Neurosurgery 50 (2002) 679–688.
Cross-Reference
Comment
Subclavian steal syndrome can occur due to stenosis or occlusion of the proximal segment of the subclavian artery. Most commonly, this lesion causes signs of vertebrobasilar insufficiency, including syncopal or near-syncopal episodes initiated by exercising the ipsilateral arm, headaches, nausea, vertigo, and other neurological symptoms. In a minority of patients, signs of brachial insufficiency are present, including upper-extremity pain, paresthesias, coolness, weakness, or fingertip necrosis.
The diagnosis is often suspected based on the clinical history and the physical finding of diminished pulse and/or diminished systolic blood pressure in the affected limb. Duplex ultrasound often demonstrates reversal of vertebral artery flow. The classic angiographic features of this diagnosis are the presence of stenosis or occlusion of the subclavian artery proximal to the vertebral artery origin, with retrograde flow down the vertebral artery seen later in the angiographic run. The lesion can be treated with either surgical bypass or angioplasty.
Notes
Case 14
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1. What anatomic variant is depicted in the first image?
2. Where does this vessel arise from?
3. What anatomic variants are depicted in the second image?
4. Where do these vessels arise from?
ANSWERS: CASE 14
Variant Anatomy: Replaced Hepatic Arteries
1. Replaced right hepatic artery.
2. Superior mesenteric artery.
3. Replaced left hepatic artery and middle hepatic artery.
4. Left gastric artery and common hepatic artery.
Reference
Covey, A.M.; Brody, L.A.; Maluccio, M.A.; et al., Variant hepatic arterial anatomy revisited: Digital subtraction angiography performed in 600 patients, Radiology 224 (2002) 542–547.
Cross-Reference
Comment
It is important to recognize the common variants in the arterial supply to the liver. Vessels can be replaced or accessory, but vessels supplying the liver are typically not redundant. A replaced artery exists when the vessel supplying an entire hepatic lobe arises aberrantly. An accessory artery exists when a portion of a hepatic lobe is supplied by a vessel of normal origin but an additional vessel of aberrant origin also supplies a portion of the lobe.
Estimates vary, but approximately 15% to 25% of people have an accessory or replaced left hepatic artery arising from the left gastric artery. When it is difficult to determine whether left hepatic branches are arising from the left gastric artery, steep left anterior oblique and lateral views can help to separate hepatic branches (which run anteriorly to the left liver lobe) and gastric fundal branches.
Approximately 15% to 20% of people have an accessory or replaced right hepatic artery arising from the superior mesenteric artery. The replaced hepatic artery is almost invariably the first branch from the superior mesenteric artery in such cases. Additional rare variants have been described in which the entire hepatic arterial supply is derived from the superior mesenteric artery or aorta.
Notes
Case 15
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1. What procedure has been performed?
2. Is general anesthesia required for this procedure?
3. Name two major complications of this procedure.
4. After the catheter is placed, what is the earliest time it can be removed?
ANSWERS: CASE 15
Percutaneous Gastrostomy Placement
1. Percutaneous gastrostomy tube placement.
2. No.
3. Peritonitis and hemorrhage.
4. One month; a mature transperitoneal tract must be present.
Reference
Laasch, H.U.; Wilbraham, L.; Bullen, K., Gastrostomy insertion: Comparing the options—PEG, RIG or PIG?Clin Radiol. 58 (2003) 398–405.
Cross-Reference
Comment
Percutaneous gastrostomy tube (G-tube) placement is performed for nutritional support in patients with inadequate oral intake or for gastric decompression in patients with chronic obstruction of the small bowel. Advantages of percutaneous G-tube placement over surgical placement include elimination of general anesthesia and its associated morbidity. Endoscopic placement has a higher incidence of aspiration and wound infection.
The basic method of G-tube placement involves the following steps: (1) The stomach is insufflated with air through a nasogastric tube; (2) Fluoroscopic confirmation of a safe access window into the stomach is confirmed, with careful attention to avoiding transcolonic or transhepatic puncture; (3) Percutaneous gastropexy may be performed via insertion of two to four metallic T-fasteners, which bring the anterior gastric wall up to the anterior abdominal wall. This is done routinely in some centers and selectively in others. Selected patients include those with ascites and patients who have diminished ability to form a secure transperitoneal tract around the catheter (e.g., patients receiving steroids); (4) A needle is placed in the gastric body, and contrast is injected to confirm intragastric positioning; (5) Over a guidewire, the tract is enlarged using sequential dilators; (6) The gastrostomy catheter is positioned in the stomach and contrast is injected to confirm adequate positioning.
Complications of percutaneous G-tube placement can include peritonitis, aspiration, hemorrhage, and tube migration. Contraindications include uncorrectable bleeding diatheses, lack of a safe access window into the stomach, massive ascites, anterior gastric wall neoplasm, and the presence of a ventriculoperitoneal shunt.
Notes
Case 16
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1. What abnormality is depicted in the images above?
2. What are the likely etiologies of such a lesion in this location?
3. What clinical problems can be associated with such a lesion?
4. What is the standard treatment for this lesion?
ANSWERS: CASE 16
Femoral Arteriovenous Fistula
1. Early filling of the left iliofemoral venous system during the early arterial phase of the angiogram, indicating a left femoral arteriovenous fistula (AVF).
2. Iatrogenic catheterization injury, trauma, postsurgical complication.
3. Vascular steal of blood from the ipsilateral limb, high-output cardiac failure.
4. Surgical repair of the femoral artery.
References
Perings, S.M.; Kelm, M.; Jax, T., A prospective study on incidence and risk factors of arteriovenous fistulae following transfemoral cardiac catheterization, Int J Cardiol. 88 (2003) 223–228.
Cross-Reference
Comment
The proper evaluation of an angiogram starts with several important observations: (1) The type of examination should be stated; (2) The catheter position and vascular approach should be noted, and the reader should specify whether nonselective or selective catheter placement has been performed; (3) The reader should be sure to observe whether the image viewed was obtained in the early arterial, late arterial, parenchymal, or venous phases of the dynamic angiographic run.
Complications of arteriography include groin infection, groin hematomas, contrast-related renal dysfunction or allergy, and arterial injuries. Injury to the femoral artery at the puncture site can result in formation of a pseudoaneurysm (which occurs in 1% of angiograms) with or without an arteriovenous fistula. The optimal site of femoral artery puncture is at the femoral head level; at this level, the common femoral artery and vein lie side by side. However, abnormally low punctures of the femoral artery can result in traversal of the femoral vein, with formation of an AVF upon removal of the catheter.
AVFs are usually asymptomatic, but they occasionally enlarge and cause arterial steal or high-output cardiac failure. Surgical ligation of femoral AVFs may be performed in patients who have symptomatic AVFs that fail to spontaneously close.
Notes
Case 17
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1. Is this more likely an acute or chronic process?
2. What is the most likely cause?
3. Would you expect the pulmonary artery pressures to be normal?
4. How does primary pulmonary hypertension differ on arteriography?
ANSWERS: CASE 17
Chronic Pulmonary Embolism
1. Chronic.
2. Thromboembolic disease.
3. No.
4. In primary pulmonary hypertension, acute or organized thrombus is not seen, and there is widespread tortuosity and severe tapering of the distal arterial branches.
Reference
Hansell, D.M., Small-vessel diseases of the lung: CT–pathologic correlates, Radiology 225 (2002) 639–653.
Cross-Reference
Comment
In most patients with acute pulmonary embolism, the emboli resolve partially or completely within several weeks of the event. However, in some patients the emboli do not resolve, and 0.1% to 0.2% of patients develop pulmonary hypertension as a result of multiple episodes of pulmonary embolism. These patients typically present with dyspnea and fatigue that is often progressive. Many patients have no history of deep venous thrombosis or prior known pulmonary embolism.
Angiography remains the gold standard for diagnosis. The findings are characteristic and include enlarged central pulmonary arteries, intra-luminal webs, pulmonary arterial branch stenoses, luminal irregularities, outpouchings often with a rounded-off appearance (as in this case), regional perfusion defects, and frank obstruction of vessels. The mean pulmonary artery pressure is typically elevated.
Notes
Case 18
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1. What are two commonly used classification systems for this disorder?
2. What imaging modalities are most accurate in the diagnosis of this disorder?
3. Based upon the second image, what complications of this disorder might be expected in this patient?
4. What role does angiography have in the management of this disorder?
ANSWERS: CASE 18
Aortic Dissection
1. DeBakey and Stanford.
2. Helical CT, magnetic resonance imaging, and transesophageal echocardiography have superseded angiography in the primary diagnosis of aortic dissection.
3. Renal and/or mesenteric ischemia.
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