Duplicated superficial femoral veins: a source of error in the sonographic investigation of deep vein thrombosis

Embolization of a duplicated femoral vein for treatment of lower extremity deep venous insufficiency: A case report

BACKGROUND

Lower extremity deep venous insufficiency (DVI) occurs secondary to structural or functional abnormalities of deep venous valves in the affected extremities. The effectiveness of surgical treatment for improvement of the hemodynamic status in these patients remains controversial in clinical practice.

METHOD

In this case report, we describe a patient who presented with severe right lower extremity edema and liposclerosis and underwent venography, which suggested a variation in the number of femoral veins. The valve within the duplicated femoral vein was significantly incompetent; however, the valve of the main trunk of the femoral vein showed normal function. We performed embolization of the duplicated femoral vein.

RESULTS

The patient tolerated the procedure well without recurrent symptoms.

CONCLUSIONS

Individualized assessment based on venography findings is useful to establish the therapeutic approach in patients with DVI.

A rare femoral venous ladder encircling the femoral artery

Femoral vein is increasingly used for venous cannulation procedures. Its anomalies in the femoral triangle could complicate these procedures. We report an extremely rare type of femoral venous ladder observed during routine cadaveric dissections. The variation was found in the left lower limb of an adult male cadaver aged 70 years. The femoral vein was a single vein in initial 3 cm and terminal 4 cm of its course. The middle part of the vein showed a duplication and a complex ladder pattern and encircled the femoral artery in the femoral triangle. This anomaly could predispose the vein for deep vein thrombosis. Knowledge of this anomaly could be useful during radiological procedures, femoral hernia repair and femoral triangle abscess and lymph node clearance.

Point-of-Care Ultrasonography in Internal Medicine: Limitations and Pitfalls for Novice Users

Point-of-care ultrasound (POCUS) is increasingly being adopted in the field of internal medicine, leading to the development of POCUS curricula in undergraduate and postgraduate medical education programs. Prominent internal medicine societies and organizations worldwide recognize the expanding utilization of POCUS by internal medicine physicians, emphasizing the need for practitioners to be aware of both its benefits and limitations. Despite the growing enthusiasm for POCUS, clinicians, particularly those with limited clinical experience, must be cautious regarding its inherent limitations and the potential impact on their clinical practice. This review aims to outline the limitations and potential drawbacks of POCUS for medical students, residents, and internists who wish to stay abreast of the escalating use of POCUS in internal medicine and have a desire, or have already commenced, to incorporate POCUS into their practice. Additionally, it provides recommendations for enhancing POCUS proficiency to mitigate these limitations.

Prevalence of femoral vein duplication: systematic review and metaanalysis

Background: Duplication of the femoral vein is an important anatomical variation of the venous anatomy which has been shown to have an impact on the diagnosis of deep venous thrombosis by compression ultrasonography. The presence of duplication may result in false negative findings while evaluating for deep venous thrombosis, with serious consequences such as pulmonary embolism and death. This metaanalysis aims to determine the pooled prevalence of duplicated femoral veins. Methods: A systematic search was conducted through the major databases PubMed, Hinari, Embase and Medline to identify studies eligible for inclusion. Appropriate data were extracted and pooled into a random-effects metaanalysis using MetaXL software. The primary and secondary outcomes of the study included the pooled prevalence of duplicated femoral veins and the prevalence of bilaterally duplicated femoral veins, respectively. Results: A total of 11 studies (n = 3,682 limbs) were included. The overall pooled prevalence of duplicated femoral veins was 19.7% (95% CI 11–30). There was a significant difference in prevalence between cadaveric studies (2%, 95% CI 1–4) and imaging studies (25%, 95% CI 17–34). Conclusion: Duplication of the femoral vein is a common variation in the lower limbs. Routine watch-out should be practiced especially when performing lower limb Doppler studies in cases of deep venous thrombosis in order to avoid misdiagnosis and improve diagnostic accuracy.

Designing S100A9-Targeted Plant Virus Nanoparticles to Target Deep Vein Thrombosis

Thromboembolic conditions are a leading cause of death worldwide, and deep vein thrombosis (DVT), or occlusive venous clot formation, is a critical and rising problem that contributes to damage of vital organs, long-term complications, and life-threatening conditions such as pulmonary embolism. Early diagnosis and treatment are correlated to better prognosis. However, current technologies in these areas, such as ultrasonography for diagnostics and anticoagulants for treatment, are limited in terms of their accuracy and therapeutic windows. In this work, we investigated targeting myeloid related protein 14 (MRP-14, also known as S100A9) using plant virus-based nanoparticle carriers as a means to achieve tissue specificity aiding prognosis and therapeutic intervention. We used a combinatorial peptide library screen to identify peptide ligands that bind MRP-14. Candidates were selected and formulated as nanoparticles by using cowpea mosaic virus (CPMV) and tobacco mosaic virus (TMV). Intravascular delivery of our MRP-14-targeted nanoparticles in a murine model of DVT resulted in enhanced accumulation in the thrombi and reduced thrombus size, suggesting application of nanoparticles for molecular targeting of MRP-14 could be a promising direction for improving DVT diagnostics, therapeutics, and therefore prognosis.

Point-of-care ultrasound for deep venous thrombosis of the lower limb

The incidence and morbidity of deep venous thrombosis (DVT) and pulmonary embolus are high. Although efforts to increase screening for DVT have been recommended, this is limited by resources. Venous duplex ultrasound has replaced venography as the first-line investigation of choice for DVT, increasing availability and reducing patient exposure to radiation and intravenous contrast. Furthermore, an abbreviated ultrasound where DVT is inferred from incomplete venous compressibility has an equivalent accuracy to venous duplex, requiring less time and training enabling its widespread use by emergency, critical care and anaesthesia clinicians. In this review, the evolution and method of lower limb venous compression ultrasound is described along with evidence for its use in patients at high risk for DVT in these clinical settings.

The Diagnostic Value of 3-Dimensional Sampling Perfection With Application Optimized Contrasts Using Different Flip Angle Evolutions (SPACE) MRI in Evaluating Lower Extremity Deep Venous Thrombus

OBJECTIVES

The aim of this study was to evaluate the diagnostic performance of noncontrast magnetic resonance imaging utilizing sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE) in detecting deep venous thrombus (DVT) of the lower extremity and evaluating clot burden.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board. Ninety-four consecutive patients (42 men, 52 women; age range, 14-87 years; average age, 52.7 years) suspected of lower extremity DVT underwent ultrasound (US) and SPACE. The venous visualization score for SPACE was determined by 2 radiologists independently according to a 4-point scale (1-4, poor to excellent). The sensitivity and specificity of SPACE in detecting DVT were calculated based on segment, limb, and patient, with US serving as the reference standard. The clot burden for each segment was scored (0-3, patent to entire segment occlusion). The clot burden score obtained with SPACE was compared with US using a Wilcoxon test based on region, limb, and patient. Interobserver agreement in assessing DVT (absent, nonocclusive, or occlusive) with SPACE was determined by calculating Cohen kappa coefficients.

RESULTS

The mean venous visualization score for SPACE was 3.82 ± 0.50 for reader 1 and 3.81 ± 0.50 for reader 2. For reader 1, sensitivity/specificity values of SPACE in detecting DVT were 96.53%/99.90% (segment), 95.24%/99.04% (limb), and 95.89%/95.24% (patient). For reader 2, corresponding values were 97.20%/99.90%, 96.39%/99.05%, and 97.22%/95.45%. The clot burden assessed with SPACE was not significantly different from US (P > 0.05 for region, limb, patient). Interobserver agreement of SPACE in assessing thrombosis was excellent (kappa = 0.894 ± 0.014).

CONCLUSIONS

Non-contrast-enhanced 3-dimensional SPACE magnetic resonance imaging is highly accurate in detecting lower extremity DVT and reliable in the evaluation of clot burden. SPACE could serve as an important alternative for patients in whom US cannot be performed.

Lack of symmetry in the major lower limb veins

BACKGROUND

Contemporary texts frequently present the venous system of the lower limb as a prime example of bilateral symmetry. However, overt bilateral asymmetry may be noted. This study was designed to examine and to quantify the level of symmetry in the lower extremity veins.

METHODS

This prospective cohort study evaluated major anatomic differences between right and left lower extremity veins in adult patients. Two hundred patients presenting with signs and symptoms of chronic venous disease (CVD; class 2-6) and venous reflux on duplex ultrasound were examined. A second group of 25 healthy volunteers without reflux or obstruction were used as controls. Those with conditions that could potentially alter vasculature, including vascular malformation, lower extremity trauma, and previously documented surgery for venous disease or bypass operations, were excluded. Only overt changes in the main superficial veins (great saphenous and small saphenous veins) and deep veins (femoral, popliteal, peroneal, and tibial veins) of the lower extremities were examined for symmetry. The level of small saphenous vein termination and thigh extension veins were also included. Location and extent of hypoplasia or aplasia and venous duplication or triplication were noted for all venous segments.

RESULTS

Of the 100 patients (200 limbs) with CVD class 2-3 (age, 49 years; range, 21-78 years), the extent of asymmetry in the superficial system, deep system, and combined was 84%, 86%, and 100%, respectively. Similarly, of the 100 patients (200 limbs) with CVD class 4-6 (age, 56 years; range, 28-84 years), the level of asymmetry in the superficial system, deep system, and combined was 83%, 84%, and 100%, respectively. Fifty (100 limbs) healthy volunteers (age, 46 years; range, 18-74 years) also presented similarly elevated levels of asymmetry compared with both cohorts of differing CVD class severity (superficial, 78%; deep, 84%; both, 100%). The most common reason for asymmetry in the great saphenous vein was hypoplasia or aplasia, whereas duplication was rare. In the small saphenous vein, the level of termination, thigh extension, and hypoplasia were the more frequent reasons. In the deep veins, duplication of the femoral and popliteal veins at different locations and extents was the most common finding for asymmetry. These findings remained consistent for all subgroups of patients and healthy controls.

CONCLUSIONS

A complete lack of symmetry is consistently seen in CVD patients and healthy subjects. Asymmetry in the veins of the lower extremities appears to be the norm. This is true despite examination of only overt changes and exclusion of multiple veins from the comparison.

Three-dimensional evaluation of the anatomic variations of the femoral vein and popliteal vein in relation to the accompanying artery by using CT venography

OBJECTIVE

We wanted to describe the three-dimensional (3D) anatomic variations of the femoral vein (FV) and popliteal vein (PV) in relation to the accompanying artery using CT venography.

MATERIALS AND METHODS

We performed a retrospective review of 445 bilateral (890 limbs) lower limb CT venograms. After the 3D relationship between the FV and PV and accompanying artery was analyzed, the presence or absence of variation was determined and the observed variations were classified. In each patient, the extent and location of the variations and the location of the adductor hiatus were recorded to investigate the regional frequency of the variations.

RESULTS

THERE WERE FOUR DISTINCT CATEGORIES OF VARIATIONS: agenesis (3 limbs, 0.3%), multiplication (isolated in the FV: 190 limbs, 21%; isolated in the PV: 14 limbs, 2%; and in both the FV and PV: 51 limbs, 6%), anatomical course variation (75 limbs, 8%) and high union of the tibial veins (737 limbs, 83%). The course variations included medial malposition (60 limbs, 7%), anterior rotation (11 limbs, 1%) and posterior rotation (4 limbs, 0.4%). Mapping the individual variations revealed regional differences in the pattern and frequency of the variations.

CONCLUSION

CT venography helps to confirm a high incidence of variations in the lower limb venous anatomy and it also revealed various positional venous anomalies in relation to the respective artery.

Femoral vein duplication: incidence and potential significance

Objective

The purpose of this study was to determine the prevalence of femoral vein duplication and the incidence of bilateral anomalies in a normal cohort of patients presenting with varicose veins.

Methods

Two hundred and forty patients underwent bilateral lower limb deep venous ultrasound examination with particular attention to the femoropopliteal segment.

Results

The incidence of femoral vein duplication was 41%. Of the 140 people with femoral vein duplications, 60 (42%) were bilateral and 80 (57%) were unilateral.

Conclusion

Femoral vein duplication is a common anatomical variant of the lower limb deep venous system. Ultrasound in skilled and experienced hands with the latest ultrasound units can readily demonstrate this venous anomaly on a consistent basis.

Utility of balanced steady-state free precession MR venography in the diagnosis of lower extremity deep venous thrombosis

OBJECTIVE

The purpose of this study was to determine the sensitivity and specificity of balanced steady-state free precession MR venography in the diagnosis of lower extremity deep venous thrombosis.

SUBJECTS AND METHODS

After undergoing lower extremity ultrasound because of suspicion of deep venous thrombosis, 64 patients were prospectively recruited to undergo balanced steady-state free precession MR venography with ultrasound as the reference standard. Ultrasound images were independently interpreted by two blinded ultrasound radiologists, and MR venograms were independently interpreted by two blinded MRI radiologists. The sensitivity, specificity, positive predictive value, and negative predictive value of MR venography were calculated for the diagnoses of all deep venous thrombosis, acute thrombi, and thrombosis of the popliteal, femoral, and common femoral veins individually. Proximal extent, thrombus age, ancillary findings, and interobserver agreement calculated with the Cohen kappa test were evaluated for ultrasound and MRI. The McNemar test was used to evaluate for statistical differences in diagnostic accuracy.

RESULTS

MR venography had a sensitivity of 94.7%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 97.7% for the diagnosis of all thrombi. For acute thrombi, the MR venography and ultrasound results were completely concordant. MR venography depicted greater proximal extent in five of 18 cases in which thrombosis was found. The MR venographic findings agreed completely with the ultrasound findings in determination of thrombus age. For both ultrasound and MR venography, interobserver agreement was 100% on a per-patient basis. No statistical difference was identified in the diagnostic performance of the two techniques.

CONCLUSION

Balanced steady-state free precession MR venography is highly accurate in the diagnosis of lower extremity deep venous thrombosis.

A duplex scan-based morphologic study of the femoral vein: Incidence and patterns of duplication

The presence of femoral vein (FV) duplicity has potential influence in the misdiagnosis of deep vein thrombosis. Also, FVs are suitable vascular substitutes, especially in the substitution of infected prosthetic grafts. The objective of this study was to describe the prevalence, anatomic patterns and characteristics of FV duplicity in adult individuals by duplex scan examination. A total of 174 adult individuals were submitted to duplex-scan examinations of both lower limbs. Individuals with duplex signs of present or previous DVT or with poor quality duplex images were excluded from the investigation. The remaining group consisted of 157 individuals (94 females), with a total of 314 limbs studied. Along with the conventional duplex investigation sequence, the FV was scanned both in transversal and longitudinal views. The number, extension and diameter of FVs were documented. It was found that 173 limbs (55.1%) had duplicated FV. Duplicity in the whole femoral extension was noted in 82 (26.1%) limbs, and out of these only 28 (8.9% of the overall number) had accessory veins with a diameter approximate to (at least 75%) the main FV. Partial (distal or proximal) duplications were seen in 89 (28.3%) limbs. A third FV was present in 28 limbs. As a possible vascular substitute, 99.0% of the main FVs and 25.4% of the accessory veins presented diameters superior to 6 mm, a suitable value for iliac substitution. In conclusion, FV duplicity is frequent, and occurred in 55% of all limbs studied. However, complete extension duplicated veins with similar diameters was an uncommon condition, noticed in fewer than 10% of limbs.

Chronic-Stage Deep Vein Thrombosis of the Lower Extremities

OBJECTIVE

To describe the computed tomographic (CT) findings of chronic deep vein thrombosis (DVT) and its evolution from acute DVT.

METHODS

Fifty-one consecutive patients with 52 legs confirmed as acute DVT by CT venography underwent follow-up computed tomography more than 2 months later. Follow-up CT findings were assessed retrospectively by consensus between 2 radiologists. The frequencies of CT findings were analyzed for affected venous segments: common iliac, external iliac, femoral, popliteal, and calf veins.

RESULTS

Twelve legs (23%) were completely normalized on follow-up computed tomography, but 40 legs (77%) showed abnormal findings as follows: luminal obliteration (n = 16), decreased caliber (n = 30), residual thrombi (n = 3), fibrotic bands (n = 28), ipsilateral muscle enlargement (n = 28), ipsilateral subcutaneous edema (n = 11), and superficial collateral vein development (n = 23). The external iliac vein (26/40, 65%) was the most commonly affected site followed in decreasing order by femoral (29/50, 58%), common iliac (9/18, 50%), popliteal (22/47, 47%), and calf veins (9/43, 21%). Trends were observed whereby luminal obliteration affected iliac veins and fibrotic bands affected femoropopliteal veins.

CONCLUSIONS

Luminal obliteration, decreased caliber, fibrotic bands, ipsilateral muscle enlargement, and superficial collateral vein development are common CT findings in chronic DVT of the lower extremity.

Current DVT imaging

Accurate diagnosis of deep venous thrombosis (DVT) is very difficult, and imaging plays a crucial role in the diagnosis or exclusion of DVT. The initial test of choice for diagnosis of acute thigh as well as upper extremity DVT is ultrasound, because of its high accuracy, relatively low cost, portability, and lack of ionizing radiation. In patients who are undergoing CT pulmonary angiography for suspected pulmonary embolism, CT venography can be performed as part of the examination, for comprehensive evaluation of the venous system in the legs, abdomen, and pelvis. MR has a problem-solving role, and conventional venography is now limited to specific scenarios including evaluation of central DVT in the upper extremities, as a prelude to intervention for thrombolysis/thrombectomy, and prior to placement of an inferior vena cava filter. This article discusses the imaging findings of DVT, and the role of these imaging examinations in the evaluation of patients with suspected DVT.

Quand et comment réaliser une imagerie des veines des membres ?

Evaluation for possible lower limb deep venous thrombosis (DVT) is a very frequently requested examination. In France, imaging diagnosis is essentially based on complete Doppler sonographic evaluation of both lower limbs. In patients with no co-morbid condition, the D-dimer assay is useful to exclude the possibility of DVT. A positive diagnosis of DVT is based on the lack of venous compressibility and abnormal Doppler signal. The diagnostic accuracy relies on adequate knowledge of vascular anatomy and sufficient training, especially at the calf level. For experienced sonographers, the accuracy is similar at the thigh and calf level. In patients with suspected pulmonary embolus, evaluation of the lower extremity veins is mandatory and frequently performed with CT immediately following CT pulmonary angiography. However, this examination has not been validated yet.

Variations in lower limb venous anatomy: implications for US diagnosis of deep vein thrombosis

PURPOSE

To retrospectively review bilateral venograms free of thrombus to evaluate the frequency and types of variations seen in venous anatomy.

MATERIALS AND METHODS

A retrospective review of 404 bilateral (808 limbs) lower limb venograms obtained from medical patients participating in a thromboprophylaxis clinical trial and found to be free of thrombus was performed. Venograms were evaluated according to predetermined criteria for the presence of duplication of vessels and inter- and intraindividual variations in venous anatomy. Variations were assessed with analysis of variance and chi2 tests.

RESULTS

Two vessels were seen in the popliteal fossa on 337 (42%) of 808 venograms, and 41 (5%) were true duplicated popliteal veins. There were 253 (31%) duplicated superficial femoral veins (SFVs), with 12 (1.5%) being complex duplicated systems. Of 265 duplicated SFVs, 138 (52%) began in the midthigh region and 80 (30%), in the adductor canal region. The duplicated vessel was medial to the main SFV in 122 (46%), lateral in 131 (49%), and both (ie, triplications) in 12 (4.5%). The length of the duplicated SFV ranged from 1 to 35 cm; 6-15 cm was the most common length in 162 (62%) SFVs. There was no significant association between the incidence of anatomic variations and age or sex (P >.1). The presence of multiple vessels in one leg was strongly correlated with the probability of occurrence in the other leg (P <.001).

CONCLUSION

Variations in lower limb venous anatomy are common and have important implications for the US diagnosis of deep vein thrombosis.

Spiral CT venography of the lower extremities by injection via an arm vein in patients with leg swelling

The purpose of this prospective study was to assess the role of spiral CT venography (CTV) via an arm vein injection in the detection of causes of leg swelling. 42 consecutive patients with leg swelling were studied with indirect spiral CTV and ultrasound (US). CT parameters were as follows: 5 mm beam collimation; 7-10 mm s(-1) table speed; and 2-3 mm reconstruction. Two consecutive spiral scans with a 40 s exposure time were performed from the pelvis to the knee. One bolus of 150 ml non-ionic contrast medium was injected at a rate of 3 ml s(-1) by a power injector via an arm vein. The delay times to the first and second scans were 120 s and 180 s, respectively. Spiral CTV demonstrated not only deep vein thrombosis (DVT) (n=12) but also other abnormalities (n=25). US showed DVT (n=10) and some other abnormalities (n=5). The sensitivity and specificity of spiral CTV for femoropopliteal DVT, as compared with US, were both 100%. Two cases of DVT in the left common-external iliac vein (iliac vein compression syndrome) detected by spiral CTV were not confirmed by US. We were able to evaluate DVT above the knee with this method. Indirect spiral CTV showed promise for the diagnosis of DVT and other soft tissue diseases in patients with leg swelling.

Radiolabeled peptides in the detection of deep venous thrombosis

Venous thrombosis and pulmonary embolism are major clinical problems that result in significant morbidity and mortality. It is estimated that 600,000 cases of pulmonary embolism occur each year in the United States, resulting in the death of approximately 100,000 patients. Most of these pulmonary emboli arise from deep venous thrombosis (DVT). The clinical diagnosis of DVT is unreliable. Only a third of patients with a clinical suspicion of DVT have objective evidence of the disease, and half of patients with proven DVT do not have any clinical symptoms. Although ascending contrast venography is the present standard for the diagnosis of DVT, duplex ultrasonography, which is increasingly used in combination with color Doppler flow imaging, is accepted as a useful clinical afternative to contrast venography. Both contrast venography and ultrasonography are imaging procedures that detect changes in venous anatomy that are caused by the presence of an intraluminal thrombus that is sufficiently formed either to reduce vascular filling with contrast medium or to resist compression. However, these imaging procedures do not reflect the metabolic activity of the clot, and therefore, they may overestimate the presence of active clots. The sensitivity of ultrasonography is also limited by various disease-related and technical factors. An alternative approach to the diagnosis of acute DVT is to detect a molecular marker of acute DVT that is not present in old, organized DVT. Recent advances in biotechnology permit the use of highly specific synthetic peptide or small molecular markers, which are involved in the acute stages of DVT formation and can be labeled efficiently with 99mTc. 99mTc-apcitide, a glycoprotein (GP IIb/IIIa) receptor antagonist previously known as 99mTc-P280, has been approved recently by the Food and Drug Administration for the clinical detection of acute DVT. Two other agents are currently under clinical investigation: 99mTc-DMP 444, which is another GP IIb/IIIa receptor antagonist, and 99mTc-Fibrin-Binding Domain (FBD), a radio-labeled fibrin-binding domain of fibronectin. Different clinical studies have shown a high diagnostic accuracy with these synthetic 99mTc-labeled peptides in the detection of acute DVT. Although further studies are needed to fully appreciate all of the diagnostic potential of these radiopharmaceuticals, the clinical introduction of 99mTcapcitide scintigraphy will certainly be helpful in expanding the use of nuclear medicine in a specific field in which it used to play a relatively marginal role.

Radionuclide venography and labeled platelets in deep venous thrombosis

99mTc-labeled macroaggregated albumin, 99mTc-labeled red blood cell, and 99mTc human serum albumin blood pool venography are simple, noninvasive imaging procedures that provide indirect evidence of deep vein thrombosis. These techniques rely on alterations in the normal venous anatomy. They do not determine the cause of venous obstruction and/or altered anatomy and cannot differentiate between acute and chronic deep venous thrombosis. In vitro labeled platelet scintigraphy provides direct evidence of active or acute thrombosis. Unfortunately, this technique requires a labor-intensive, lengthy labeling process and has a high number of false-negative results in patients who receive heparin therapy.

Role of ultrasound in the assessment of chronic venous insufficiency

Chronic venous insufficiency (CVI) is responsible for significant morbidity and health expenditure. Doppler ultrasound techniques provide a noninvasive method for identifying structural and functional abnormalities associated with CVI; this information then allows treatment options to be considered. Ultrasound allows clear identification of specific venous segments and provides information on the patency of these segments, the presence or absence of reflux, perforator veins, collateral channels, or patterns of recurrence after surgery. Techniques for the assessment of the lower limb veins are described, as are the techniques for the elicitation and quantification of reflux.

Thrombosis in a duplicated superficial femoral vein in a patient with haemophilia A

Venous thrombosis is a very rare occurrence in patients with haemophilia A. We report the case of a haemophiliac in whom initially a calf haematoma was suspected, but neither this nor deep venous thrombosis (DVT) could be confirmed on ultrasound scanning. Subsequently, a high segment venous thrombosis was diagnosed by venography in a portion of a duplicated superficial femoral vein. Treatment with factor VIII (FVIII) and low molecular weight heparin led to a successful resolution. The only other case we have been able to find in the literature occurred during FVIII replacement therapy, which was not the situation with our patient.

Imaging evaluation of suspected pulmonary embolism

Venous thromboembolism (VTE) is a common disorder that is difficult to diagnose clinically but carries significant morbidity and mortality if untreated. Additionally, although demonstrated to be of benefit in cases of proven deep vein thrombosis (DVT) and pulmonary embolism (PE), anticoagulation therapy is not without risk. Because the clinical exam is known to be unreliable for the detection of both DVT and PE, many imaging modalities have been used in the diagnostic imaging algorithm for the detection of VTE, including chest radiography, ventilation/perfusion (V/Q) scintigraphy, pulmonary angiography, and recently, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Chest radiographic findings in acute PE include focal oligemia, vascular enlargement, atelectasis, pleural effusions, and air space opacities representing pulmonary hemorrhage or infarction. The chest radiograph can occasionally be suggestive of PE but is more often nonspecifically abnormal. The main use of the chest radiograph in the evaluation of suspected PE is to exclude entities that may simulate PE and to assist in the interpretation of V/Q scintigraphy. Lower extremity venous compression ultrasonography (CU) is both sensitive and specific for the diagnosis of femoropopliteal DVT, and the value of negative CU results has been established in outcomes studies. However, the reliability of CU for the detection of isolated calf vein thrombosis is not well established, and the clinical significance of such thrombi is debatable. Additional methods such as color and spectral Doppler analysis are also useful in the diagnostic evaluation of DVT but are best considered as adjuncts to the conventional CU examination rather than as primary diagnostic modalities themselves. Compression ultrasonography and Doppler techniques are useful in the evaluation of suspected upper extremity DVT; spectral Doppler waveform analysis is particularly useful to assess for the patency of veins that cannot be directly visualized and compressed with conventional gray-scale sonography. V/Q scintigraphy has been the initial modality obtained in patients suspected of PE for a number of years. Although many studies have investigated the role of V/Q scintigraphy in the evaluation of VTE, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has provided the most useful information regarding the utility of V/Q scintigraphy in this setting. A high probability scan interpretation is sufficient justification to institute anticoagulation, and a normal perfusion scan effectively excludes the diagnosis of PE. A normal/near normal scan interpretation also carries a sufficiently low prevalence of angiographically proven PE to withhold anticoagulation. Although the prevalence of PE in the setting of low probability scan interpretations is low and several outcomes studies have demonstrated a benign course in untreated patients with low probability scan results, patients with inadequate cardiopulmonary reserve do not necessarily have good outcomes. Such patients deserve more aggressive evaluation. Patients with intermediate probability scan results have a 20% to 40% prevalence of angiographically proven PE and thus require further investigation. The radionuclide investigation of DVT includes such techniques as radionuclide venography and thrombus-avid scintigraphy. Although these methods have not been as thoroughly evaluated as CU, studies thus far have indicated encouraging results, and further investigations are warranted. Pulmonary angiography has been the gold standard for the diagnosis of PE for decades. Studies have indicated that angiography has probably been underutilized by referring physicians for the evaluation of suspected PE, likely because of the perception of significant morbidity and mortality associated with the procedure. (ABSTRACT TRUNCATED)