Renal Artery Variants in Patients with Normal Renal Function

3D volume rendered CT image shows a 2nd right renal artery (arrows) arising from the right common iliac artery

Facts

• "Normal" renal arterial arrangement = single bilateral renal arteries with hilar segmental branching. This occurred in 46% of cases in a landmark angiographic report published in 1978
• Normally, no intrarenal arterial anastomoses are present. Each artery represents an end artery -- interruption results in infarction of that segment
• Variations include double renal arteries, triple renal arteries, pre-hilar segmental branching, fetal lobulation and exaggerated size difference (greater than 2 cm). 
• Most common variations are multiple renal arteries followed by pre-hilar segmental branching

Knowledge of Renal Vascular Variations is Important For:

• Renal transplantation
• Renovascular hypertension
• Vascular reconstruction for congenital and acquired lesions
• Reconstructive surgery for abdominal aortic aneurysms

Our case: Double right renal artery with the smaller branch originating from the common iliac artery

Reference:

- Harrison, Jr., et al. Incidence of anatomical variants in renal vasculature in the presence of normal renal function. Ann Surg 1978;188:83-89.

- Ozkan U, et al. Renal artery origins and variations: angiographic evaluation of 855 consecutive patients. Diagn Interv Radiol 2006;12:183-6.

Vertebral Artery Hypoplasia

Curved reformat of the normal-caliber right vertebral artery showing all 4 segments of the artery. 

Curved reformat of the left vertebral artery shows diffuse, small caliber of the artery.

Facts:

• Operational definitions are either 1) asymmetrical ratio of or greater than 1:1.7, or 2) discrepancy of greater than 2 mm diameter
• Prevalence 2%-6% of population (from autopsy and angiographic series)

Clinical Relevance

• Posterior circulation ischemia: hypoplasia leads to reduction of posterior circulation blood flow velocity therefore has a negative role in occlusion of major cerebral arteries
• Migraine with aura and vestibular neuronitis: hypoplasia is believed to be associated with regional hypo perfusion and complex neurovascular consequences

Reference:

Chuang YM, Chan L, Wu HM, et al. The clinical relevance of vertebral artery hypoplasia. Acta Neurol Taiwan 2012;21:1-7.

Updated Nomenclature of Vasculitides

A sagittal-curved-reformatted CT image of the aorta of a 31-year-old man demonstrate extensively calcified intima and focal narrowing of the mid/distal thoracic aorta, consistent with Takayasu arteritis.

Very recently, the international consensus conference addressed the revision of the nomenclature of systemic vasculitides as follows:

• LARGE-vessel vasculitis: Takayasu arteritis and giant cell arteritis
• MEDIUM-vessel vasculitis: polyarteritis nodosa, Kawasaki disease
• SMALL-vessel vasculitis: ANCA-associated vasculitis (microscopic polyangiitis, Wegener, Churg-Strauss), immune complex vasculitis 
• VARIABLE-vessel vasculitis: Behcet disease, Cogan syndrome
• SINGLE-ORGAN vascuiltis: cutaneous leukocytoclastic angiitis, primary CNS vasculitis, and others
• Vasculitis associated with systemic diseases such as lupus, rheumatoid arthritis and sarcoid
• Vasculitis associated with probable etiology (e.g., associated with viral hepatitis, drugs) 

Categorization by vessel size reflects the arteries those are predominantly affected. Vasculitis in each category can affect any size artery. 

Reference:

Jennette JC, et al. 2012 revised international chapel hill consensus conference nomenclature of vasculitides. Arthritis Rheum 2013;65:1-11.

Superficial Femoral Vein: Misleading Medical Nomenclature

Anatomy and Definition of Superficial Femoral Vein (SFV)

• SFV, as understood by vascular surgeons and radiologists, is a continuation of the popliteal vein. After joining the deep femoral vein, it becomes common femoral vein
• Superficial femoral vein is actually a "deep" vein

The Problem

• Most vascular surgeons and radiologists understand that SFV is a deep vein, but many physicians in other specialty or general practitioners do not
• Based on a survey of multispecialty groups, only 24% of physicians would give anticoagulants to patients having "acute thrombosis of the superficial femoral vein". There is a misperception of many physicians that SFV is superficial vein, therefore it would not be treated as deep vein thrombosis

Recommendations: Don't Use "Superficial Femoral Vein". Use "Femoral Vein"

• Current consensus developed by experts in phlebology officially established “femoral vein” as the vein that originates from the popliteal vein and courses in the femoral canal and bluntly discarded “superficial femoral vein” as an “unauthorized term" … because it is a deep vein 
• SFV is not in the official Terminologica Anatomica
• The other vein is "deep femoral vein" or "profunda femoris vein"
• Supported by International Interdisciplinary Consensus Committee on Venous Anatomical Terminology convened on September 8–9, 2001 (Nomenclature of the veins of the lower limbs: an international interdisciplinary consensus statement. J Vasc Surg 2002; 36:416-422)
•  Supported by Society of Interventional Radiology

Reference:
Hammond I. The superficial femoral vein. Radiology 2003;229;604-666 (link)

Infected (Mycotic) Aortic Aneurysm

An axial CT image shows a saccular aneurysm (arrowheads) arising from the infrarenal abdominal aorta (arrow), with periaortic soft tissue attenuation and fat stranding. Infected aortic aneurysm was confirmed at surgery.

Facts

• It is a consequence of infectious aortitis with wall being weak and ruptured forming a false lumen or pseudoaneurysm
• Most common location = infrarenal aorta
• Most common causative agent = Salmonella
• Route of infection = hematogenous, contiguous seeding, traumatic/iatrogenic inoculation
• Mycotic = infection not confined only to fungus (use of mycotic aneurysm can be misleading)

Imaging

• Aneurysm mostly saccular
• Aneurysm size ranging from 1-10 cm
• Around aneurysm: gas, soft tissue stranding, fluid
• Can be confused with neoplasm, infected lymph nodes or hematoma

Reference:

Restrepo CS, Ocazionez D, Suri R, Vargas D. Aortitis: imaging spectrum of the infectious and inflammatory conditions of the aorta. RadioGraphics 2011;31:435-451.

Caval Index

Longitudinal ultrasound images of the IVC in an asymptomatic patient demonstrate a normal inferior vena cava (IVC) during inspiration and expiration, in which the diameters (yellow double-headed arrows) do not change significantly. In this case, the diameters of the IVC were measured 2-3 cm below the right atrial border (yellow lines).

Facts: IVC Diameter

• IVC diameter changes following total body volume (increases with increasing total body volume, and decreases with volume depletion)
• IVC normally collapses with inspiration (decreased intra-thoracic pressure) and expands with expiration (but this collapsibility should not exceed 50%)

Caval Index

• Caval Index = 100 x (diam expiration - diam inspiration)/diam expiration
• Where to measure the IVC? Several ways exist, and none is perfect yet. Easy way is to measure with a longitudinal view of the IVC - find the junction of the atrium and IVC and measure the IVC at 2-3 cm below the junction
• Interpretation: studies vary greatly as to significance of values in different patient populations. In general, if caval index is greater than 50% it suggests low central venous pressure (CVP less than 8 mmHg) and high probability of fluid responsiveness

Reference:

Nagdev AD, Merchant RC, Tirado-Gonzalez A, et al. Emergency department bedside ultrasonographic measurement of the caval index for noninvasive determination of low central venous pressure. Ann Emerg Med 2010; 55:290-295.

Partial Anomalous Pulmonary Venous Return (PAPVR)

Figures 1-3: Contiguous axial contrast-enhanced CT images show an abnormal left upper lobe pulmonary vein draining into the left vertical vein (arrows) that subsequently empties into the left brachiocephalic vein (BCV).

Facts: PAPVR

• Common venous anomalies of the thorax (0.5% prevalence in general population)
• Pulmonary-to-systemic, left-to-right shunt
• Anomalous pulmonary vein drains into the right sided circulation (SVC, azygos, brachiocephalic, IVC, coronary sinus, right atrium)
• Symptomatic if large or associated with other cardiopulmonary anomalies
• Most common form = right upper lobe vein draining into SVC, left upper lobe vein draining into left vertical vein
• Surgical correction recommended if pulmonary-to-systemic flow ratio greater than 1.5 to avoid progression to pulmonary hypertension and right ventricular failure

Reference

Martinez-Jimenez S, Heyneman LE, McAdams HP, et al. Nonsurgical extracardiac vascular shunts in the thorax: clinical and imaging characteristics. Radiographics 2010; 30,e41-.

Post-Endovascular Rx of Thoracic Aortic Injury

An axial CT image shows a normal appearance of an endovascular stent in the descending thoracic aorta in a patient who suffered thoracic aortic injury.

Facts: Treatment and Follow Up of Thoracic Aortic Injury (TAI)

• Open thoracotomy with direct repair of TAI is a traditional means for Rx of TAI. However, endovascular Rx has become more common given its less invasiveness and many reports demonstrating smaller mortality rate
• Endovascular Rx is used to exclude pseudoaneurysm from systemic arterial pressure
• Patients who had endovascular Rx for TAI will require regular imaging follow-ups. Most institutions perform CT angiography at the time of discharge, at 1-3 months, at 6 months, at 1 year and then annually.
• Purpose of follow up CT angiography after endovascular Rx is to 1) assess quality of pseudoaneurysm exclusion, 2) detect related complications
• Complications potentially detectable on imaging (rare): endoleak, graft collapse, branch vessel complications (stroke, arm ischemia), stent migration, etc

Normal Imaging Findings

• Endograft = metallic framework with a zigzag appearance (covered by polytetrafluorethylene or polyester material)
• Must compare the CT angiography with prior angiography (post-stent) or prior post-operative CT
• Check for position of endograft (should be unchanged), apposition/seal with the aortic wall (should be completely sealed), patent endograft lumen (without narrowing or sharp angulation), total exclusion of aortic injury

Reference

Morgan TA, Steenburg SD, Siegel EL, Mirvis SE. Acute traumatic aortic injuries: posttherapy multidetector CT findings. Radiographics 2010; 30:851-867

Upper Extremity Deep Vein Thrombosis

An ultrasound image shows an echogenic thrombus and absence of color flow in the right axillary veins (arrows).

Facts: Upper Extremity Deep Vein Thrombosis

• Secondary form (more common) is believed to be due to intimal injury, venous stasis and hypercoagulability. Primary form (Paget-von Schrotter syndrome) occurs in young adults due to underlying chronic venous compressive abnormality caused by musculoskeletal structures in the costoclavicular space
• Axillosubclavian vein most common location because it is relatively fixed in the thoracic outlet, therefore it is exposed to repeated trauma with arm movement
• Etiology: central venous catheter (CVC), permanent cardiac pacer, mediastinal tumors, radiation, surgery, hypercoagulable states
• Increasingly common. 8% of all DVTs
• Complications: pulmonary embolism, SVC syndrome, postthrombotic venous insufficiency, loss of vascular access
• The most powerful independent predictor of UEDVT = presence of CVC (increases the risk by 7 folds)
• Other risk factors in patients without CVC: young age, lean body weight and inpatient status

Imaging

• US is the imaging modality of choice
• US shows lack of compressibility, absence of color flow signal and augmentation, visualization of thrombus
• Radiography may show cervical rib, fractured rib or clavicle

References:

1. Joffe HV, Kucher N, Tapson VF, et al. Upper-extremity deep vein thrombosis: a prospective registry of 592 patients. Circulation 2004;110:1605-1611.

2. Greben C and Charles HW. Deep vein thrombosis, upper extremity. In eMedicine, updated Jul 28, 2009.

Renal Artery Aneurysm

Axial CT image shows a large partially thrombosed aneurysm of the right renal artery, which is extraparenchymal. On other images, the aneurysm is saccular, and appears to arise from the segmental artery.

Facts:

• True aneurysms involve all layers of the artery and usually inherited. They can be fusiform or saccular, and are more commonly extraparenchymal in location. Example: fibromuscular dysplasia, Ehlers-Danlos
• False aneurysms involve only some layers of the artery, usually are acquired and saccular. Examples: trauma, iatrogenic, dissection, mycotic
• Intrarenal aneurysms are intraparenchymal, can be either true or false aneurysm. Examples: polyarteritis nodosa, tuberculosis, neurofibromatosis

Indications for Intervention

• Symptomatic: rupture, pain, ischemia, infarction, hypertension
• Diameter more than 2 cm, enlarging or dissection
• Female patient who is pregnant, or contemplating pregnancy

Our case: False aneurysm probably due to dissection, surgical removal was performed in this symptomatic patient

Reference:

Lew WK, Weaver FA, Otero CA, et al. Renal artery aneurysm. E-medicine, updated September 17, 2008

Superficial Thrombophlebitis

Longitudinal US image of the antecubital fossa shows an echogenic clot in the basilic vein (arrows).

Facts: Superficial Thrombophlebitis

• Also known as superficial venous thrombosis
• Presence of thrombus in the lumen of superficial vein, followed by inflammation of the wall and adjacent tissues
• Variable degree of severity, can be in small venous tributaries but can extend into deep veins or, uncommonly, result in pulmonary embolism
• Related to Virchow's triad
• Prodromes of many systemic diseases (neoplasm, arteriopathy, collagen vascular disease) and syndromes (Trousseau, Mondor disease, Lemierre, Buerger disease)

Imaging

• Color Doppler US provides definitive diagnosis by showing clot, uncompressibility, absence of flow

Reference:

Sobreira ML, Yoshida WB, Lastoria S. Superficial thrombophlebitis: epidemiology, physiopathology, diagnosis and treatment. J Vasc Bras 2008;7. Available here.

Endoleak after EVAR

Axial CT images of the same level during precontrast, arterial phase and delayed phase of enhancement show an endoleak at the right posterolateral aspect of the endovascular stent graft (arrow). The endoleak was visualized only in the delayed image. Aortic wall calcification noted in all images (arrowheads).

Facts: Endoleak

• One of the complications of endovascular aortic aneurysm repair (EVAR)
• Blood flow external to the stent-graft and inside the aneurysm sac
• Aneurysm sac communicates with the systemic circulation, most commonly, through reversal of flow through aortic branch vessels
• Difficult to diagnose and treat, management remains a controversy
• Classification system organizes endoleak into 5 types based on "source of blood flow"
• Most common type of endoleak after abdominal aortic aneurysm repair = type II, in which retrograde blood flow through aortic branch vessels into the aneurysm sac. Typical sources = inferior mesenteric and lumbar arteries.

Types of Endoleak

• I = attachment site leak (either proximal or distal)
• II = collateral-vessel leak
• III = graft failure - midgraft hole, junctional leak, or disconnect
• IV = graft-wall porosity
• V = endotension

Imaging Surveillance

• Lifelong imaging surveillance required after EVAR
• Ideal frequency not well defined, but usually done at 1 and 6 months after initial repair - then every 6 months thereafter
• CT angiography most widely used, multiphase is recommended
• Endoleaks have variable flow rates, therefore they can be detected at variable times after contrast administration. Some can be detected only on arterial phase or delayed phase (as in our case)

Reference:

Stavropoulos SW, Charagundla SR. Imaging techniques for detection and management of endoleaks after endovascular aortic aneurysm repair. Radiology 2007;243:641-655.

Blunt Traumatic Vertebral Artery Dissection

Fig.1: Axial CT image of the cervical spine shows a fracture of the right facet (arrows) extending to the transverse foramen of C6 in a neurologically intact blunt trauma patient.
Fig.2: Subsequent CT angiography of the neck shows a long-segment occlusion (red arrows) of the right vertebral artery from C6 up to base of the skull.

Why Screening for Blunt Cerebrovascular Injury (BCVI) in Trauma Patients?

• If left untreated, carotid and vertebral artery injury can have a stroke rate ranging from 3-100% and 6-100% respectively
• Stroke rate by BCVI depends on grade of injury: the higher the grade, the higher stroke rate
• Screening protocols based on patient injury patterns and mechanism of injury have been instituted prior to neurologic sequelae to identify these injuries in asymptomatic patients and to initiate stroke-preventive treatment.
• Based on current studies, early anticoagulant therapy reduces stroke rates and prevents neurologic morbidity from BCVI

Facts: Denver Screening Criteria

• General guidelines to determine which blunt cerebrovascular injury (BCVI) patients should be evaluated for arterial injury.
• Signs/symptoms of BCVI: arterial hemorrhage, cervical bruit in patient less than 50 years of age, expanding cervical hematoma, focal neurologic deficit, neurologic exam incongruous with head CT scan findings, stroke on secondary CT scan
• Risk factors for BCVI: high-energy transfer mechanism with LeFort II or III fracture, cervical spine fracture pattern (subluxation, fracture extending into the transverse foramen, fractures of C1-C3), basilar skull fracture with carotid canal involvement, diffuse axonal injury with a Glasgow Coma Scale score less than 6, near hanging with anoxic brain injury

Facts: Denver Grading Scale for BCVI

• Grade I: irregularity of the vessel wall or a dissection/intramural hematoma with less than 25% luminal stenosis
• Grade II: intraluminal thrombus or raised intimal flap is visualized, or dissection/intramural hematoma with 25% or more luminal narrowing
• Grade III: pseudoaneurysm
• Grade IV: vessel occlusion
• Grade V: vessel transection

Injury Patterns on Imaging That Should Raise a Suspicion for BCVI

• Interfacet subluxation/dislocation
• Fracture lines reaching an arterial structure
• C1-C3 fracture
• Basilar skull fracture with carotid canal involvement
• LeFort II or III fracture due to high-impact trauma

Reference:

1. Cothren CC and Moore EE. Blunt cerebrovascular injuries. Clinics 2005;60:489-496.

2. Delgado Almandoz JE, Schaefer PW, Kelly HR, et al. Multidetector CT angiography in the evaluation of acute blunt head and neck trauma: a proposed acute craniocervical trauma scoring system. Radiology 2010 (published online before print December 17, 2009).

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Left Inferior Vena Cava (IVC)

Axial contrast-enhanced CT images show the left IVC (arrows) crossing the midline from left to right of the aorta, joining the left renal vein that units with the right renal vein to be a normal right sided suprarenal IVC. Image at the lower section shows the IVC located to the left of the aorta. Without scrutinization, this anomaly can be misdiagnosed as left paraaortic adenopathy.

Facts: IVC Anomalies

• As many as 14 forms of IVC anomalies are theoretically possible
• More than one anomaly can coexist in a patient, for example, double IVC + retroaortic right renal vein + hemiazygos continuation
• Common anomalies are circumaortic left renal vein, retroaortic left renal vein, left IVC, double IVC, azygos continuation of IVC

Left IVC

• Regression of the right supracardinal vein with persistence of the left supracardinal vein
• Prevalence 0.2% - 0.5%
• Left IVC joins the left renal vein, which crosses anterior to the aorta and units with the right renal vein to form a normal right sided suprarenal IVC.
• Clinical significance: potential for misdiagnosis as left paraaortic adenopathy, difficulty placement of IVC filter

Reference:

Bass JE, Redwine MD, Kramer LA, et al. Spectrum of congenital anomalies of the inferior vena cava: cross-sectional imaging findings. RadioGraphics 2000;20:639-652.

Popliteal Artery Aneurysm

Figure 1: Gray-scale ultrasound of the let popliteal ultrasound shows a fusiform aneurysm of the popliteal artery, measuring 2 cm.
Figure 2: Color Doppler US image shows partial thrombosis of the aneurysm.

Facts:

• Most common peripheral artery aneurysm
• Most commonly due to atherosclerosis
• More common in male
• Commonly bilateral (need to examine the contralateral popliteal artery), and commonly associated with abdominal aortic and iliac artery aneurysm in about half of all cases.
• Presentation: cold lower extremity from acute thrombosis or distal embolization, asymptomatic pulsatile popliteal fossa mass, rarely rupture

Indication for Repair

1. Size 2 cm or greater
2. Intraluminal thrombus

Imaging Strategy

• Doppler US for diagnosis and follow up
• MDCT for planning of repair (surgical or endovascular): extent, location of associated peripheral vascular disease, nearby branch vessels, size and angulation of the aneurysm

References

1. Blackbourne LH. Surgical recall, 5th ed, 2008.

2. Funaki B, Lorenz J, Ha TV. Teaching atlas of vascular and non-vascular interventional radiology, 2007.

Double Aortic Arch

A scout CT image of a 70-year-old woman shows subtle prominence of the right paratracheal soft tissue. There is slight narrowing the trachea at the level of the left aortic arch. The patient also has a large hiatal hernia.

Coronal reformatted CT image shows a double aortic arch, in which the right-sided arch is approximately about the same size as the left.

Facts: Double Aortic Arch

• Most common symptomatic vascular ring
• Ascending aorta divides anterior to the trachea into left and right arches; right arch typically is larger and more superiorly located than the left arch and passes posterior to the esophagus joining the descending aorta
• Complete ring around trachea and esophagus may cause compression
• Usually not associated with congenital heart disease (if it is, tetralogy of Fallot predominates)
• Rarely presents in adulthood (as in our case)

Imaging

• Diagnosis often suggests by the presence of right sided aortic arch on radiography
• Barium esophagography shows bilateral indentations of the esophagus in AP view
• CT and MRI confirms the diagnosis. The size of each arch, degree of atresia (if present), branching patterns and degree of compression should be reported.

References:

1. McMillan JA, et al. Oski's pediatrics: principles & practice, 4th ed, 2006.

2. Moss AJ, et al. Moss and Adam's heart disease in infants, children, and adolescents, 7th ed, 2007.

Splenic Artery Aneurysm

Figures 1&2: Axial contrast-enhanced CT images (2nd image is a maximum-intensity projection image) show a 2-cm saccular aneurysm (arrows) of the mid splenic artery in a 38-year-old woman with idiopathic hepatic cirrhosis, portal hypertension and splenomegaly. CA = celiac artery

Facts About Splenic Artery Aneurysm

• Most common visceral artery aneurysm
• Incidence up to 7% in autopsy series, nearly 1% on abdominal angiographic series
• Most are saccular
• Most are in mid or distal splenic artery
• Women > men

Etiology

1. Degenerative from underlying medial fibrodysplasia (atherosclerosis not considered to be the primary etiology)
2. Inflammatory: almost always related to pancreatitis and pseudocysts
3. Posttraumatic
4. Pregnancy related: high association with mortality for mother and fetus with ruptured aneurysms

Treatment

Most surgical literature recommends repair if

• Larger than 2 cm
• Enlarging on follow ups
• Pregnant patients or in women of childbearing age who might become pregnant

Open repair or endovascular therapy

Reference:

Kandarpa K. Peripheral Vascular Intervention. Lippincott Williams & Wilkins, 1st edition (October 1, 2007).

Aortic Intramural Hematoma (IMH)

Figure 1: Contrast-enhanced CT image shows thickening of the aortic wall at the anteromedial aspect of the descending aorta (arrow). There is linear calcification, indicating atherosclerosis.

Figure 2: Axial CT without IV contrast at the same level shows the area of aortic wall thickening as a slightly hyperdense wall of the aorta (arrow). The linear calcification (arrowhead) is indeed located close to the aortic lumen (likely in the intima), therefore the wall thickening is 'subintimal' or 'intramural'. The nonenhanced CT helps in the way that if one looks only at contrast-enhanced images, one might think that the findings represent atherosclerotic change of the aorta (with calcification and intraluminal thrombus) and defers the diagnosis of IMH.

Facts: Intramural Hematoma (IMH)

• Less common variant of aortic dissection
• Hemorrhage occurs within aortic wall without initial intimal disruption believed to be due to medial degeneration predisposing the vasa vasorum toward hemorrhage
• Increasingly recognized with the use of CT imaging (in the past, it is believed to be underdiagnosed on angiography because there is no intimal flap)
• Limited data suggests a similar clinical course and mortality rate to acute aortic dissection
• Common presentations = chest pain and interscapular back pain (similar to aortic dissection)
• Unlike aortic dissection, IMH occurs in men equal to women, with absence of traditional risk factors for dissection (e.g. bicuspid aortic valve, Marfan syndrome, collagen vascular disease)

Imaging Features

• Focal or diffuse, smooth thickening of the aortic wall
• No intimal flap or any communication between aortic lumen and IMH
• Intimal calcium (if present) is superficial (closer to lumen) to the hematoma

It May Be Confused With:

• Aortic dissection with thrombosed false lumen
• Penetrating atherosclerotic ulcer - usually irregular thickening of the aortic wall
• Aortic aneurysm with intraluminal thrombus - if intimal calcium is present, it will be deeper to the hematoma. The thrombus usually is irregular and rough - not smooth.

Our case - Intramural hematoma of the descending thoracic aorta.

Reference:
Sawhney NS, DeMaria AN, Blanchard DG. Aortic intramural hematoma. Chest 2001;120:1340-1346.

Inferior Vena Cava (IVC) Filter Fracture

Figure 1: Abdominal radiograph shows that one of the legs (arrows) of the IVC filter is pointed away from the expected IVC lumen.

Figure 2: Axial CT image confirms that one of the legs (arrow) of the IVC filter has migrated out of the IVC wall into an adjacent tissue.

Fracture of IVC Filter Element

If the fragment migrates to adjacent tissues

- Asymptomatic patient: no treatment necessary

- Symptomatic patient: confirm location with CT scan and consider surgical removal if feasible

If fracture results in compromise of filter function: place a second filter

Reference:

Kaufman JA. Vena Caval Filters. In: Kandarpa K and Aruny JE, eds. Handbook of interventional radiologic procedures. 3rd ed. 2002

Persistent Left Superior Vena Cava (SVC)

Fig. 1: Portable chest radiograph shows a right PICC line coursing from the right arm to the left side of the mediastinum (arrows).
Fig. 2: Coronal chest CT image performed with injection of the right antecubital vein shows dense contrast in the right axillary, subclavian, left brachiocephalic vein to the left SVC (arrowheads). There is no right SVC.

Persistent Left SVC

• Persistence of left anterior cardinal vein
• 0.3% of normal population; 4.4% in patients with congenital heart disease
• In most cases, the right SVC is also present (82% - 90%) (i.e. double SVC)
• Left SVC courses lateral to the aortic arch, main pulmonary artery, anterior to the left hilum and typically enters the coronary sinus that drains into the right atrium
• In some cases, left SVC enters the left atrium. Left SVC draining into the left atrium is highly associated with intracardiac defects (commonly ASD)

Significance of left SVC

• Need to know before performing SVC-pulmonary artery anastomosis
• Need to know before performing open heart operation

Reference:

1. Shumacker HB, King H, Waldhausen JA. The persistent left superior vena cava. Surgical implications, with special reference to caval drainage into the left atrium. Ann Surg 1967;165:797-805.

2. Webb WR, Gamsu G, Speckman JM, et al. Computed tomographic demonstration of mediastinal venous anomalies. AJR 1982;139:157-161.