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Insonation (Hand-Held Doppler Examination)
An assessment using the hand-held Doppler probe is widely accepted as the minimum
level of investigation before treatment is initiated. Its utility in the evaluation of primary
and uncomplicated varicose veins is well established (29–31). With practice, it can
identify flow and detect clinically significant reflux in the superficial veins reliably (32)
and can also be used to exclude arterial disease.
Basic principles. The frequency of ultrasound transmitted from the transmitting
crystal (T) strikes an interface (I) which is moving towards the transducer (Fig. 4). The
frequency of the reflected signal is increased and is received by the receiving transducer
(R). The Doppler instrument is designed to extract this frequency shift or difference.
This difference is small and within the audible range and hence can be amplified by
feeding into an output device such as the loudspeaker. When the angle between the
ultrasound beam and the reflector is 908 there is no detectable Doppler shift frequency.
Therefore, the angle between transducer and reflector should be less than 608
whenever possible (33–35).
Continuous wave hand-held Doppler is the most basic Doppler system. The
transducer assembly has both a transmitter element and a receiver element so that the
sound is transmitted and received continuously. A filter is used to remove large, low-
frequency components from the signal. These instruments are small, inexpensive, good for
superficial vessels and very sensitive to weak signals. However, they are unable to produce
any form of image of the underlying vessel, or to determine from what depth or from how
many vessels the Doppler signals are being received.
The technique of examination using the hand-held Doppler is simple and easily
acquired. With the patient standing, the Doppler probe is placed over the saphenofemoral
junction and the calf squeezed to augment forward flow through the junction which is heard
as a characteristic “whoosh.” This confirms good “sonic contact.” The calf compression is
then released. Any significant reflux through the junction would result in a secondprolonged
“whoosh.” The probe is then placed over the LSV where it is visibly distended or otherwise
just above the knee, where its location is predictable, and the calf squeezed and released to
detect any reflux in the vein. A prolonged “whoosh,” both at the groin and over the LSV,
would indicate an incompetent saphenofemoral junction and LSV to the point of
examination. Isolated truncal incompetence in the LSV may sometimes occur in the
presence of a competent saphenofemoral junction. Insonation over the LSV may be
repeated after occluding theLSV either digitally or with a tourniquet proximally in the thigh
or at the knee level. Elimination of a previously demonstrable refluxing signal or “whoosh”
would confirm superficial venous incompetence. Reflux across the saphenofemoral junction
during hand-held Doppler probe testing may also be elicited by asking the patient to cough
Figure 4 The Doppler effect. Abbreviations: T, transmitting crystal; I, interface; R, receiving
transducer.
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(36) or to carryout a Valsalva manoeuvre. The short saphenous system is similarly testedby
placing the probe over the popliteal fossa bearing in mind the anatomical variations in the
termination of the short saphenous vein (37). If the findings are inconclusive after a hand-
held Doppler examination, a duplex ultrasonography should be performed.
The hand-held Doppler is also useful to estimate the ankle-brachial pressure index in
suspected arterial insufficiency in patients presenting with varicose veins.
Duplex Ultrasonography
This allows direct visualization of the veins and provides anatomical and functional
information. By detecting flow, they are helpful in identifying vessels that appear too
small in the 2D image.
It is controversial as to whether a hand-held Doppler examination alone is
sufficient for assessment of all primary long saphenous vein incompetence, especially if
surgical treatment is planned. Resource constraints, perhaps more than scientific
rationale, often precludes the routine use of duplex ultrasonography in all such patients.
However, in the authors’ opinion and experience, a limited duplex scan can be performed
in clinic in patients with uncomplicated LSV incompetence in much the same time as
a hand-held Doppler examination. There are instances when a more detailed examination
is warranted whether or not hand-held Doppler demonstrates reflux. These include:
† Reflux in the popliteal fossa—because of variation in the position of the
sapheno-popliteal junction (which needs to be surface marked prior to surgery)
and to differentiate superficial venous reflux from deep vein incompetence.
† Clinical features of chronic venous insufficiency.
† Recurrent varicose veins—because of a more complex morphology (38).
† History of deep vein thrombosis, limb swelling or significant trauma or fracture
to the limb—to study the flow in the deep veins and perforators. Superficial
varices that develop after deep vein thrombosis may be the only route of
venous outflow from the limb.
† Atypical distribution of varicose veins and uncertainty regarding sites
of incompetence.
† Selection of patients for new therapies such as endovenous ablation techniques
using radiofrequency energy, laser or foam sclerotherapy, and the use and
follow up of these treatments.
† Varicose veins associated with arteriovenous fistulae—to study the flow pattern
and extent of the lesion and for follow up after surgery or embolisation.
Duplex ultrasonography is now accepted as the gold standard in the above
circumstances to precisely identify the pathophysiology and site and extent of
abnormality. A systematic examination of the superficial and deep venous system is
performed to obtain a comprehensive “venous” map of the leg. Duplex ultrasonography
has largely replaced venography in this respect.
CLASSIFICATION OF VENOUS DISEASE
CEAP Classification
The CEAP classification (39,40) was originally devised by experts under the auspices of
the American Venous Forum in 1994 to address the diagnostic needs of patients with
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chronic venous disease. It defines the clinical class (C) of the problem, its aetiology (E),
its anatomic distribution in the veins of the extremity (A) and its underlying pathologic (P)
mechanism (reflux, obstruction or both). It also provides a severity rating scale and
a disability scale. The diagnostic tests are used based on the severity of venous disease.
This classification provides a scientific way of categorizing the entire range of chronic
venous disease with diagnoses determined by objective testing (40).
Michael’s Classification
The CEAP classification is sometimes too elaborate for the purposes of a clinical trial on
a specific sub-group of patient population. Michael’s classification is simple and easy
to use in an outpatient setting and has a direct and pragmatic bearing on treatment (41).
The classification uses information obtained from physical and hand-held Doppler
examination and defines groups of patients that are most likely to benefit from particular
forms of intervention. Complications of varicose veins, the need for recurrent groin or
popliteal surgery and factors that influence the suitability for surgery or sclerotherapy such
as site, size and extent of varicosities are all taken into consideration.
Basle Classification
It is not widely used nowadays since the advent of the CEAP classification and is not
suitable for use in a clinical trial (42).
REFERENCES
1. Callam MJ. Epidemiology of varicose veins. Br J Surg 1994; 81:167–173.
2. Smith JJ, Garratt AM, Guest M, et al. Evaluating and improving health-related quality of life
in patients with varicose veins. J Vasc Surg 1999; 30:710–719.
KEY POINTS
† Diseases of the venous system cause significant morbidity and have a major
socio–economic impact on society.
† Outpatient assessment of venous disease should be carried out by specialists
ideally in a dedicated “one-stop” venous clinic. Inadequate assessment can
result in poorer treatment outcome and patient dissatisfaction.
† The three most common presentations of lower limb venous disease are
pain, swelling and skin changes in the lower third of the leg. Cosmesis is
another significant reason for seeking medical attention.
† The aim of clinical assessment is to detect and localize the underlying
pathophysiology and to identify any risk factors.
† Physical examination includes inspection, palpation, auscultation and
insonation using the hand-held Doppler. The latter is an indispensable
tool in clinical assessment.
† Clinical diagnosis of DVT is unreliable. However, DVT can safely be ruled
out if clinical probability is low and d–dimer test is negative. Duplex
ultrasonography is the imaging modality of choice in suspected cases.
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3. Garratt AM, Macdonald LM, Ruta DA, et al. Towards measurement of outcome for patients
with varicose veins. Qual Health Care 1993; 2:5–10.
4. Sparey C, Haddad N, Sissons G, et al. The effect of pregnancy on the lower limb venous system
of women with varicose veins. Eur J Vasc Endovasc Surg 1999; 18:294–299.
5. Evans CJ, Fowkes FG, Hajivassiliou CA, et al. Epidemiology of varicose veins. A review.
Int Angiol 1994; 13:263–270.
6. Sinnatamby CS. Chapter 3: Lower Limb. In: Sinnatamby CS, ed. Last’s Anatomy Regional and
Applied 10th ed. Edinburgh, New York: Churchill Livingstone, 1999:101–110.
7. Negus D. The Surgical Anatomy of the Veins of the Lower Limb. In: Dodd H, Cockett FB, eds.
The Pathology and Surgery of the veins of the lower limb. 2nd ed. New York: Churchill
Livingstone, 1976:18–49.
8. Gabella G. Veins of the lower limb. In: Bannister LH, Berry MB, Collins P et al, eds. Gray’s
Anatomy. 38th ed. 1995:1595–1598.
9. Scurr JH. Venous Disorders. In: Russell RCG, Williams NS, Bulstrode CJK, eds. Bailey &
Love’s Short Practice of Surgery. 24th ed. 2004:954–973.
10. Ludbrook J. Applied physiology of the veins. In: Dodd H, Cockett FB, eds. The Pathology and
Surgery of the veins of the lower limb. 2nd ed. 1976:50–55.
11. Nicolaides AN, Zukowski AJ. The value of dynamic pressure measurements. World J Surg
1986; 10:919.
12. Hanrahan LM, Araki CT, Rodriguez AA, et al. Distribution of valvular incompetence in
patients with venous stasis ulceration. J Vasc Surg 1991; 13:805.
13. Sethia KK, Darke SG. Long saphenous incompetence as a cause of venous ulceration. Br J Surg
1984; 71:754.
14. Hoare MC, Nicolaides AN, Miles CR, et al. The role of primary varicose veins in venous
ulceration. Surgery 1982; 92:450.
15. Bass A, Chayen D, Weinmann EE, et al. Lateral venous ulcer and short saphenous vein
insufficiency. J Vasc Surg 1997; 25:654.
16. Darke SG, Penfold C. Venous ulceration and saphenous ligation. Eur J Vasc Surg 1992; 6:4–9.
17. Lees TA, Lambert D. Patterns of venous reflux in limbs with skin changes associated with
chronic venous insufficiency. Br J Surg 1993; 80:725–728.
18. Scott TE, La Morte WW, Gorin DR, et al. Risk factors for chronic venous insufficiency: A dual
case-control study. J Vasc Surg 1995; 22:622.
19. Adhikari A, Criqui MH, Wooll V, et al. The epidemiology of chronic venous diseases.
Phlebology 2000; 15:2–18.
20. Bradbury AW, Evans C, Allan PL, et al. What are the symptoms of varicose veins? Edinburgh
Vein Study cross-sectional population survey BMJ 1999; 318:353–356.
21. Giannoukas AD. Chapter 29: Venous and lymphatic diseases. In: Lumley JSP, ed. Hamilton
Bailey’s Physical Signs. Demonstrations of Physical Signs in Clinical Surgery. 18th ed.
Oxford: Butterworth-Heinemann, 1997:381–396.
22. Leu AJ, Leu HJ, Franzeck UK, et al. Microvascular changes in chronic venous insufficiency:
A review. Cardiovasc Surg 1995; 3:237.
23. Wells PS, Hirsh J, Anderson DR, et al. Accuracy of clinical assessment of deep-vein
thrombosis. Lancet 1995; 346(8973):516.
24. Cranley JJ, Canos AJ, Sull WJ. The diagnosis of deep venous thrombosis. Fallibility of clinical
symptoms and signs. Arch Surg 1976; 111:34–36.
25. Donada C, Galofaro G, Maccioni A, et al. Unreliability of the clinical diagnosis in deep venous
thrombosis of the lower limbs. Minerva Med 1990; 81:61–66 [Article in Italian].
26. Wells PS, Anderson DR, Rodger M, et al. Evaluation of d-Dimer in the Diagnosis of Suspected
Deep-Vein Thrombosis. N Engl J Med 2003; 349:1227–1235.
27. Sumner DS. Chapter 7: Essential hemodynamic principles. In: Rutherford RB, ed. Vascular
Surgery. 5th ed. Philadelphia: W.B. Saunders Company, 2000:73–120.
28. Browse NL. Chapter 7: The arteries, veins and lymphatics. In: Browse NL, ed. An Introduction
to the Symptoms and Signs of Surgical Disease. 3rd ed. London: Arnold, 1997:180–195.
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29. McIrvine AJ, Corbett CRR, Aston NO, et al. The demonstration of saphenofemoral
incompetence: Doppler ultrasound compared with standard clinical tests. Br J Surg 1984;
71:509–510.
30. Mitchell DC, Darke SG. The assessment of primary varicose veins by doppler ultrasound; the
role of sapheno-popliteal incompetence and the short saphenous system. Eur J Vasc Endovasc
Surg 1987; 1:113–115.
31. Milliken JC, Dinn E, O’Connor R, et al. A simple Doppler technique for the rapid diagnosis of
significant sapheno-femoral reflux. Phlebology 1986; 1:125–128.
32. Campbell WB, Niblett BM, Ridler BMF, et al. Hand-held Doppler as a screening test in
primary varicose veins. Br J Surg 1997; 84:1541–1543.
33. Williamson MR. Chapter 1: Physics in ultrasound. In: Williamson MR, ed. Essentials of
Ultrasound. New York: W.B. Saunders Company, 1996:1–28.
34. McDicken WN, Hoskins PR. Physics: Principles. Practice and Artefacts. In: Allan PA,
Dubbins PA, Pozniak MA, McDicken WN, eds. Clinical Doppler Ultrasound. 1st ed. 2000:1–25.
35. Farrant P, Meire HB. Chapter 9: Doppler Ultrasound. In: Farrant P, Meire HB, eds. Basic
Ultrasound. Chinchester: Wiley, 1995:56–67.
36. Darke SG, Vetrivel S, Foy DMA, et al. Comparison of duplex scanning and continuous wave
doppler in the assessment of primary and uncomplicated varicose veins. J Vasc Endovasc Surg
1997; 14:457–461.
37. Chan A, Chisolm I, Royle JP. The use of directional ultrasound in the assessment of saphenous
incompetence. Aust NZ J Surg 1983; 53:399–402.
38. Darke SG. The morphology of recurrent varicose veins. Eur J Vasc Surg 1992; 6:512–517.
39. Kistner RL, Masuda EM. Chapter 145: A practical approach to the diagnosis and classification
of chronic venous disease. In: Rutherford RB, ed. Vascular Surgey. 5th ed. Philadelphia:
W.B. Saunders, 2000:1990–1999.
40. Kistner RL, Eklof B, Masuda EM. Diagnosis of chronic venous disease of the lower
extremities: the “CEAP” classification. Mayo Clin Proc 1996; 71:338–345.
41. Michaels JA, Campbell WB. A new pragmatic classification system for varicose veins.
Phlebology 2001; 16:29–33.
42. Madar G, Widmer L, Zemp E, et al. Varicose veins and chronic venous insufficiency disorder
or disease. Vasa 1986; 15:126–134.
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8
Noninvasive Evaluation of
Venous Disease
Ahmad Bhatti
Division of Vascular Surgery, Loyola University Medical Center, Maywood, Illinois,
U.S.A.
Nicos Labropoulos
Vascular Laboratory, Division of Vascular Surgery, New Jersey Medical School, Newark,
New Jersey, U.S.A.
INTRODUCTION
Anatomy, flow, valve function, and occlusion are the primary variables that are
assessed non invasively. Evaluation of these parameters can be direct (e.g., doppler
ultrasonography) or indirect/physiologic (e.g., plethysmography). The disease states that
prompt these investigations can be broken down into reflux and obstruction. These
methods have allowed us to increase our understanding on the pathophysiology of chronic
venous disease (CVD). As a consequence the management of CVD has also improved.
PHYSIOLOGIC TESTS
They provide quantitative measurements of venous hemodynamics. The severity of the
CVD in the limbs can be globally assessed. However, they do not provide targeted
segmental evaluation and the distribution and extent of CVD is not known. Thus using
them alone it is difficult to instigate appropriate treatment. They are very helpful in
monitoring the effects of conservative and interventional treatment.
AIR PLETHYSMOGRAPHY
Air plethysmography involves pressure cuffs that are placed on the leg. Changes in
volume are transduced to changes in pressure via the polyurethane air bladders in these
cuffs. Measurements are taken in supine and standing positions and after certain
maneuvers. Several measurements can be obtained: functional venous volume (VV),
ejection fraction (EF), venous filling index (VFI), and residual volume fraction (RVF).
These measurements, along with patient maneuvers during the exam, can help evaluate
for reflux, obstruction, and calf-pump function. Reproducibility of this test in patients
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with venous disease has been brought into question (1,2). Additionally, these parameters
are absolute and do not take limb size into account.
Reflux is evaluated with the patient in supine position and the legs are elevated in
order to empty the veins. The patient is asked to stand to allow filling of the veins until
a plateau is reached. VV is the amount of blood from the baseline to the plateau and is
approximately 70–110 cc in normal individuals (3). VFI measures the amount of blood
that fills the veins. A slow filling which is !2 ml/s indicates the absence of significant
reflux. The higher the value of VFI the worse the problem. Patients with venous
insufficiency may have a VV of up to 400 cc (4). VV, VFI, and RVF rise with increasing
reflux (3). Venous ulcer formation is more likely with increasing VFI and RVF (5,6).
Obstructive changes may also be measured by the outflow fraction (OF). With the
patient in supine position and limb elevation, a thigh tourniquet is applied and inflated to
80 mmHg. The VV volume will rise and plateau. Then the tourniquet is rapidly deflated
and the veins are emptied. The slower the emptying the worse the obstruction. The OF is
measured at one second and a normal value is O40%. The test can also be performed with
digital occlusion of the greater saphenous vein (GSV) to assess its outflow contribution.
PHOTO PLETHYSMOGRAPHY
Photo plethysmography (PPG) works on the principal of blood absorption of infrared
light that is maximally absorbed by hemoglobin. These are the same principles employed
in oxygen pulse oximetry. An infrared light and sensor are mounted to one another in
a PPG. Infrared light is emitted from the transmitter, and the sensor detects the amount of
light reflected back. Blood absorbs this infrared light, so increases in local blood volume
decrease reflection to the sensor. Special algorithms and/or sensors are used to subtract
out arterial artifacts when venous studies are performed. Quantitative digital PPG goes
one step further and automatically calibrates itself and provides amplitude measurement.
A volume-time tracing is created using this method. For reflux studies, the patient is
seated and an emitter/sensor is applied to their calf. The patient then performs several
tiptoes to empty the venous system. PPG records a decrease in the blood volume.
All measurements are relative and qualitative. The patient then stops and the arteries
refill the venous system slowly in a normal limb. In the patient with reflux, the venous
system will refill faster. While the time-volume curve is important to assess, a refilling
time (RT) greater than 23 seconds is normal, and less than 20 seconds is consistent with
reflux (7). If a short RT is noted, the test is repeated with a narrow cuff below the knee to
occlude the superficial veins. After cuff inflation and repeat testing, a repeat short RT
indicates deep venous incompetence, whereas normalization indicates superficial venous
incompetence. Although PPG can detect the presence of venous disease or reflux, its
correlation to severity of disease is poor (8,9).
LIGHT REFLECTION RHEOGRAPHY
Light reflection rheography (LRR) is similar to PPG except that it is designed to minimize
artifact from the patient’s skin or surface (e.g., stockings). To assess for venous reflux, the
same measurements, techniques, and limitations apply as in PPG.
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STRAIN GAUGE PLETHYSMOGRAPHY
Ambulatory strain gauge plethysmography (SGP or ASGP) measures calf volume
changes. Variations of the actual strain gauge device exist, but all devices essentially
measure the diameter supramalleolar ankle during testing (10). This reduces artifact from
calf contraction and produces more reproducible results (11). The patient then performs
20 knee bends in 40 seconds to 60 degrees. The expelled volume (EV) and refill time (RT)
are calculated. Both EV and RT decrease with increasing severity of venous disease. Cuffs
can be applied to occlude the superficial venous system in an attempt to attribute abnormal
findings to the deep or superficial system.
FOOT VOLUMETRY
Foot volumetry employs similar principles to other plethysmographic studies. A container
filled with water is equipped with a photoelectric sensor that relays the water level
(volume) to a recording device. The foot is immersed after various maneuvers, and the foot
volume recorded with each immersion. Foot volumes are measured initially and then after
20 knee bends. Parameters such as expelled volume (EV), expelled volume rate (EVR),
and refilling flow (Q) are measured. A cuff may then be applied to occlude the superficial
venous system, and the measurements repeated to differentiate between deep and
superficial venous pathology. EV has been shown to correlate with venous pressure in
normal and pathologic exercised limbs (12). Foot volumetry parameters have also been
shown to correlate with the clinical class/severity of venous insufficiency (13).
CONTINUOUS WAVE DOPPLER
Doppler ultrasound can only detect the presence or absence of reflux in those systems
being assessed. With the patient standing upright to maximize venous engorgement and
reflux (if present), a Doppler probe is placed at a 458 angle to the skin in the same plane as
the axial stream. Each vein segment is individually probed. Antegrade flow is elicited by
brisk calf or thigh compression, and a Doppler signal is heard. If a second prolonged sound
is heard after the release of the compression this is reflux. The absence of signal during
the compression indicates occlusion. In areas like the popliteal fossa it can determine the
presence of reflux but it will be unable to determine its origin (small saphenous versus
gastrocnemial versus popliteal). Also it will be falsely negative for thrombosis in patients
with partial luminal occlusion and in those with duplicated veins. Nowadays it is not
commonly performed as it provides limited information. It remains a fast, simple, and
inexpensive screening tool for reflux (14,15).
DUPLEX ULTRASOUND
Duplex ultrasound scanning (DUS) combines color flow imaging with B-mode and
pulsed Doppler. This provides anatomic detail, visualization of flow, and flow velocity
data. It is noninvasive, relatively portable, and low priced, but it is operator dependent.
DUS has largely supplanted venography as a routine study for assessment of CVD. It has
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become the test of choice in many cases, including assessing primary and recurrent
venous reflux (16,17).
A thorough history and physical exam is paramount, as this will highlight areas of
importance and provide relevant information such as previous thrombosis or venous
surgery. The test starts with the patient standing with support of their body weight on the
contralateral limb. It has been shown that this is the best position for testing reflux and
the supine position should no longer be used (18). If the patients are unable to stand for
long then the sitting position may be used.
The different veins are tested for reflux by rapidly squeezing and suddenly releasing
of the calf or other muscle beds. At the groin the Valsalva maneuver may also be
performed. In obese patients and in those with edema a dorsi/plantar flexion may be used
if the compression is unable to augment flow sufficiently (18). Automatic rapid inflation-
deflation cuffs may also be used especially when precise measurements are needed.
Different transducers can be changed as needed, as superficial and deep veins may require
different frequencies particularly in the obese and edematous limbs. All main veins are
imaged and assessed along their entire lengths. Nonsaphenous, accessory veins and
tributaries should be noted and studied accordingly (19,20). The venous anatomy is
complex. The examiner should be aware of the different variations such as duplications
(common in popliteal and femoral, rare in the saphenous veins) hypoplasia (saphenous
veins) and segmental aplasia (posterior tibial and GSV). These are important for the
accurate diagnosis and may also have an impact on the management of the patient.
Throughout the exam, color flow imaging is used on top of the B-mode ultrasound.
Typically, red indicates arterial flow, and blue indicates venous flow. Therefore, any red
(retrograde) flow in a vein indicates reflux. Increasing venous back pressure should produce
no retrograde flow. Some reflux behind competent valves is physiologic (21,22). Reflux has
been recently defined as a retrograde flow lasting O1000 ms in the femoropopliteal veins,
O500 ms in the deep calf veins, deep femoral vein and the superficial veins, and O350 ms
in the perforator veins (18). The risk for skin damage is proportional to the degree of reflux.
The distribution and extent of reflux throughout thelimb’s venoussystem alsocorrelate with
clinical severity of chronic venous insufficiency (23). Reflux may exist in the superficial
and/or deep system. The perforators are assessed in the ankle, calf andthe thighin theirusual
locations. Additionally, localized varicose veins should heighten suspicion for an
underlying incompetent perforator, and that region may require further evaluation. Ulcers
and other wounds should not prevent examination of the underlying veins. Covering the
probe with a sterile glove, or covering the wound itself with a transparent sterile dressing,
allows for adequate assessment (24).
COMPUTED TOMOGRAPHIC VENOGRAPHY
Several studies have suggested performing computed tomographic venography (CTV) of
the lower extremities at the same time a CTA of the pulmonary arterial tree for suspect
pulmonary embolism (PE) is performed (25,26). One study compared CTV to DUS and
found CTV to be 100% sensitive and 97% specific for pelvic or thigh deep venous
thrombosis (DVT) from the iliac crests to knees (26). Another study compared CTV to
ultrasound for DVT in the same anatomic region and found 100% sensitivity and specificity
(27). CTV is generally limited to anatomic information of veins between the iliac crest and
knees, and therefore cannot assess reflux or pathology in calf veins. CTV is not currently
being used to assess CVD. Its role appears to be limited to evaluate for DVT in patients as
a venous thromboembolic (VTE) source. However, there is limited experience with using
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CTV for anatomic evaluation of the venous system. This includes assessment of venous
anatomy in post-operative varicose vein recurrence, or in evaluation for May-Thurner
syndrome (28,29).
MAGNETIC RESONANCE VENOGRAPHY
Magnetic resonance venography (MRV) allows assessment of the pelvic and iliac veins.
It has an advantage over venography and DUS in assessing the internal iliac veins for
thrombosis (30). It has been cited as beingas sensitiveand specificas venography(93–100%
and 95–97% respectively) (31–34). This includes, unlike CTV, assessing calf veins for DVT
or anatomy (33,35). Thrombus age may also be estimated by MRV (36,37). Three-
dimensional views of the venous system can be reconstructed. Lesions significant to venous
pathology, such as in May-Thurner syndrome, can also be diagnosed concordantly (38).
Predominate disadvantages of this technique are those that apply to MR in general: motion
artifact, metallic implant and claustrophobia.
KEY POINTS
† The noninvasive tests measure the severity and anatomic extent of reflux and
obstruction.
† The plethysmographic tests are good to assess venous hemodynamics of the limb
but with their use alone appropriate treatment cannot be instigated.
† Duplex ultrasound has become the method of choice for assessing venous
disease. It can detect reflux obstruction in individual veins and allow imaging of
other pathologies.
† Computer tomography can detect pulmonary embolism and proximal vein
thrombosis during the same exam.
† Magnetic resonance venography is used in detection of thrombosis and is
particularly useful in the evaluation of pelvic veins.
REFERENCES
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venous function of the lower leg. Clinical Physiology & Functional Imaging 2002; 22:379–382.
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3. Labropoulos N, Giannoukas AD, Nicolaides AN, Veller M, Leon M, Volteas N. The role of
venous reflux and calf muscle pump function in nonthrombotic chronic venous insufficiency.
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4. Nicolaides AN. Investigation of chronic venous insufficiency: A consensus statement.
Circulation 2000; 102:E126–E163.
5. van Rij AM, Solomon C, Christie R. Anatomic and physiologic characteristics of venous
ulceration. J Vasc Surg 1994; 20:759–764.
6. Araki CT, Back TL, Padberg FT, et al. The significance of calf muscle pump function in venous
ulceration. J Vasc Surg 1994; 20:872–877.
7. Sarin S, Shields DA, Scurr JH, Coleridge Smith PD. Photoplethysmography: a valuable
noninvasive tool in the assessment of venous dysfunction? J Vasc Surg 1992; 16:154–162.
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