A standardized ultrasound approach to pelvic congestion syndrome

Introduction

Pelvic congestion syndrome (PCS) is a disorder that affects women of reproductive age and often presents with chronic pelvic pain (CPP) for at least six months. Other symptoms include pelvic heaviness, dyspareunia, dysmenorrhea, lumbar pain, urinary frequency, and signs of vulvar, perineal, gluteal or lower limb varices, and hemorrhoids.^1,2 CPP in women may be attributed to a variety of pathologies including endometriosis, adhesions, uterine leiomyomata, adenomyosis, malignancy, and uterine prolapse. ³ Because of the nonspecific clinical presentation, PCS is a diagnosis of exclusion and often missed or misdiagnosed in many patients. Another potential explanation for the underdiagnoses of PCS as a cause for CPP was attributed to psychosomatic disorders. Due to increased awareness over the last decades, PCS has been recognized as a common cause of CPP in premenopausal women. ⁴ Predisposition to the development appears to be multiparity due to the increase in intravascular volume, weight gain, and anatomic changes that lead to valve incompetency, blood pooling, and venous obstruction during pregnancy. ⁵ Multiple diagnostic approaches are well documented within the literature. Noninvasive studies such as pelvic duplex ultrasound (DUS), transvaginal ultrasound (TVUS), computed tomography (CT), and magnetic resonance (MR) are utilized. Invasive diagnostic procedures include vulval varicography, per-uterine venography, selective ovarian venography, and laparoscopy. The current gold standard for diagnosing PCS remains selective ovarian venography. Although it remains debatable what the most accurate and precise modality for the diagnosis is, ultrasonography has been widely accepted as the first-line test to identify pelvic venous incompetence and/or varicose veins in the appropriate population of patients. The aim of this paper was to delineate an easy, reproducible method of using the DUS to obtain abdominal windows tracing the ovarian veins, document their diameter, and most importantly using various maneuvers to detect the presence of reflux in these veins.

Imaging technique

The examination is performed after the patient has been fasting overnight. This decreases the likelihood of bowel gas obstructing the vascular structures and therefore increase the sensitivity of the examination. The patient is placed in the supine position with head elevation of 30°. A curvilinear array transducer 2–5 MHz is most often utilized or 1–5 MHz in obese patients. The vessels examined are the inferior vena cava (IVC), left renal vein (LRV), iliac veins, ovarian veins, trans- and peri-uterine veins, and the tributaries of the internal iliac veins (Figure 1). OPEN IN VIEWER

Left ovarian vein

The probe is placed transversally to the left side of the aorta in the mid-abdomen to detect the LOV. At this location, the ovarian vein lies just anterior to the psoas muscle. After identifying the LOV, the probe is placed longitudinally and moved upward to visualize the communication of the LRV with LOV (Figure 5). Moving toward the pelvis, one may encounter multiple trunks originating from the venous plexus of the broad ligaments of the uterus near the ovary. Two ovarian veins originate bilaterally, following the path of the ovarian artery and coursing together on each side of the artery. From our experience, there is a wide range of anatomic variability regarding the number of ovarian vein trunks and their interconnection, as well as their termination. In an anatomic study of 200 gonadal veins, Lechter et al. demonstrated that these veins originated from one to six trunks in their lower third and as they ascended to the middle and upper third merged to form fewer trunks. The classically described pattern of one terminal trunk of the LOV draining into the LRV was observed in about 80% of the veins. ¹⁰ After visualization of the LOV, the probe is moved further caudally to determine the middle and distal parts of the ovarian vein to document any dilation. The distal LOV crosses over the left proximal external iliac vein. The flow pattern is examined with the Doppler setting. Spontaneous reflux with continuous flow would suggest compression of the LRV resulting in renal venous drainage to the LOV. Intermittent reflux signifies isolated LOV incompetence and can be elicited with a controlled Valsalva maneuver by taking a small breath and bearing down. In the majority of patients however, reflux is evident without performing this maneuver. The sonographic and venographic appearance of the LOV after coil embolization is seen in Figure 6. OPEN IN VIEWER

Figure 5.

Imaging of the LOV. (a–c) The position of the transducer is demonstrated along the course of the LOV. (d) and (e) A normal LOV is seen in longitudinal view with a diameter of 5.4 mm and antegrade flow. (f) and (g) Color and Doppler flow of the LOV demonstrating reflux. Compression of the left iliac fossa distal to LOV imaging site normalized the flow temporarily and after the release of the compression regrade flow is seen. (g) LOV reflux seen on Doppler flow seen. (h) Duplication of the distal LOV measuring 7.2 mm and 6.6 mm. This is very common and often more than two veins are found at this level. (i) Venogram showing two LOV trunks (black arrows) with reflux extending into the peri- and trans-uterine veins (arrowhead).

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Figure 6.

LOV after coil embolization. (a) The LOV occlusion after coil embolization. Ring down artifacts are seen in the vein, which is typical of small metallic structures. (b) Venography of the LOV showing coils and no residual reflux. (c) Occluded distal LOV seen under real-zoom magnification demonstrating coils occupying the entire LOV lumen. Chronic luminal changes with fibrosis are evident in the lumen between the two coils. (d) Coils in the LOV with foam creating a hazy artifact during the procedure.

Peri- and trans-uterine plexus

Following the path of the distal part of the ROV (Figure 7), the probe is moved medially to visualize the peri- and trans-uterine veins with the probe in transverse orientation. This is approximately 5 cm or lower below the umbilicus as seen in Figure 8. In this position, pelvic varices originating from the uterine plexus can be visualized. In the supine position, slow flow is present and reflux is evident with Valsalva maneuver. If these veins are not adequately visualized, the examination may be continued with the patient in the standing position with the probe being placed in the perineal space. OPEN IN VIEWER

Figure 8.

Visualization of the peri- (PUV) and trans-uterine veins. (a) The transducer is positioned in transverse orientation below the umbilicus. The smaller image shows the approximate position in relation to the umbilicus. (b) and (c) The arrow points at the left PUV plexus in B-Mode. The color flow image has been captured during Valsalva maneuver, which augmented the dilation and flow within the PUV plexus. (d) Image showing significant dilation of the right PUV measuring 11.5 mm in diameter. (e) CTV signifying bilateral dilated PUV (arrow). (f) Selective venography revealing reflux in the left PUV crossing over to the right side through the trans-uterine plexus.

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Figure 9.

Demonstration of the sapheno-femoral junction (SFJ). (a) Orientation of the transducer is in longitudinal fashion to visualize the great saphenous vein draining into the CFV with the patient in standing position to elicit and document potential reflux. (b) Example of a competent right SFJ. (c) Left SFJ reflux in a patient who had pelvic reflux draining into the left SFJ. The SFJ is dilated and has retrograde flow with aliasing due to high velocity during the Valsalva maneuver.

Connection with pelvic floor and lower extremities

To examine the connection of the pelvic floor with the lower extremities, the patient is asked to stand up. This will help to increase visualization of pelvic varicosities and reflux from the pelvis to the groin, inner thigh, and gluteal area due to hydrostatic pressure. The probe is placed in longitudinal direction in the groin to visualize the sapheno-femoral junction and identify potential reflux from the pelvis (Figure 9). The probe is moved medial to identify the superficial external pudendal veins and other connections in the perineal and vulvar area (Figures 10 and 11). Veins in the posterior thigh are followed to the gluteal area to demonstrate connections and reflux deeper to the gluteal fascia. Those steps are repeated on the right side as well. OPEN IN VIEWER

Figure 10.

Evaluation of the pelvic veins through the perineal space. (a) The transducer is placed to demonstrate in the perineal area with the patient standing. (b) and (c) Large PUV is seen with a diameter measuring 11.6 mm. Reflux with high velocity and long duration is elicited with the Valsalva maneuver. (d) Prominent and congested right PUV plexus with many dilated TUV are seen on color flow imaging. (e) Another example of dilated left PUV with reflux in the standing position. (f) Doppler flow of the right PUV with high velocity >50 cm/s and long duration reflux >15 s. In the standing position during the Valsalva, maneuver is easy to demonstrate the hemodynamic effect of the refluxing veins. In >90% of cases in our practice, this can be done with a linear transducer as shown in these images.

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Figure 11.

Imaging of veins in the inner thigh and vulvar area. Often dilated veins are seen in this area. The transducer is placed medial to the SFJ and gradually moved to the vulvar area. Refluxing veins connecting with the pelvis may also be found anterior to the SFJ, in gluteal area and posteromedial thigh. Pelvic veins can drain into the sciatic nerve veins and reflux may be apparent in superficial vein in the lower thigh and popliteal fossa. (a) To augment the visualization of the pudendal veins, the patient remains in the standing position utilizing increased hydrostatic pressure. (b) and (c) Color flow demonstrates reflux coming from the deep internal pudendal and obturator veins into inner thigh and vulvar varicosities. (d) and (e) Doppler and color flow showing reflux during Valsalva maneuver in lower perineal and vulvar veins extending into SFJ tributaries.

Discussion

After excluding common causes of CPP and with a high clinical suspicion of PCS from the history and physical examination, ultrasonography is commonly used as a first-line diagnostic approach. There is a lack of training and experience for the abdominal/pelvic venous system. This paper describes a standardized technique in a logical fashion that addresses all the important structures that may be involved in the development of PCS symptoms and provide an easy-to-perform approach that can be acquired by experts as well as beginners and can be implemented into current teaching curricula. TVUS may be the preferred first-line test by gynecologists to investigate for other pathologies with a high probability of visualizing the peri-uterine veins. Whiteley et al. ¹¹ evaluated the use of TVUS in the diagnosis of PCS and proposed this to be the new gold standard, however this diagnostic imaging modality is limited by the inability to demonstrate the course of the ovarian veins and potential higher obstructions, however this diagnostic imaging modality is limited by the inability to demonstrate the course of the ovarian veins and potential higher obstructions that may include the Nutcracker phenomenon or May-Thurner syndrome.

Transabdominal ultrasound is a diagnostic tool to assess the entire venous system from the diaphragm to the perineum and is therefore a more advantageous imaging modality. Pathologies that cannot be visualized with TVUS, such as compression of the LRV from the Nutcracker phenomenon can be easily identified. It is also noninvasive, widely available, cost-effective, and lacks the radiation or the use of contrast as compared to other imaging modalities. The greatest benefit of this modality is the dynamic feature where patients are able to change positions from supine to standing as well as perform the Valsalva maneuver. The utilization of the standing position increases the hydrostatic pressure in the pelvic venous system, leading to the dilation of veins and revealing potential reflux. This enables real-time visualization of blood flow and possible reflux during these diagnostic maneuvers and may increase the diagnostic confidence. A feature that may not be available or extremely difficult to perform with other imaging modalities. Overall, this technique is able to gain more diagnostic insight compared to other approaches.

The current literature is lacking any prospective, randomized controlled trials addressing the optimal imaging diagnostic modality for PCS. There are many case reports and small case series that utilize various imaging modalities including ultrasound,^12,13 MRI, ¹⁴ and CT ¹⁵ and even a smaller subset of publications that specifically have numbers for sensitivity and specificity for DUS, ¹⁶ but they do not address all the pathologies that may be involved in PCS such as iliac vein and LRV compression syndromes.

Although this technique offers a great method and dynamic study to demonstrate the anatomical structures involved in PCS, it certainly has limitations. The performance of transabdominal US and the visualization of structures depend strongly on the experience and ability of the technician. Furthermore, incomplete penetration of ultrasound waves will limit the image quality in obese patients. Although, from our experience most females who were diagnosed with PCS at our institution, were not obese. To demonstrate this, we randomly selected 30 patients who underwent transabdominal ultrasound examination for PCS. The mean body mass index was 24.67 ± 4.47 (n = 30; 95% confidence interval 23.00–26.34; range 19.2–36.8). Similarly, poor visualization of the vessels may occur in those patients who have increased bowel gases at the time of examination. However, this can be overcome with the patient being in the upright position.

As discussed earlier, transabdominal ultrasound is the first-line test after screening for other pathologies. In the event of a positive finding, one should proceed to perform a selective venogram to confirm the diagnosis and with the intention to treat. In some centers, a transvaginal approach may be preferred if experience is lacking. If ultrasonography is unavailable, one may elect to use axial imaging such as CT or MRI (Figure 12). OPEN IN VIEWER

Criteria for sonographic diagnosis of PCS in the appropriate patients have been suggested by various authors. These included various ovarian vein diameter cut-offs starting above 4 mm, positive reflux, presence of pelvic varicosities, and reflux during Valsalva maneuver. ¹² Although Dos Santos et al. suggest no correlation between vein diameter and venous reflux, ¹⁷ from our experience, we disagree with this statement. In patients with suspected PCS, the diameter of the veins was measured and we noted that the larger the diameter of the vein, the greater the chance of reflux. However, the main diagnostic criteria remains the documentation of reflux in the ovarian veins, due to the observations of large ovarian veins without reflux and conversely small ovarian veins that were incompetent. Another observation was made in patients with incompetent LOVs that had ROV dilation without reflux (Figure 7). In such cases, the ROV dilates to compensate for the pelvic overflow from the refluxing LOV. This is clearly depicted in the selective catheterization of the LOV where the refluxing blood ascends into ROV.

Conclusion

The described transabdominal technique takes all potential pathologies that can contribute to PCS into account and in experienced hands, it can consistently demonstrate the ovarian veins as well as document their diameter and possible reflux. If successful, the patient can potentially avoid other expensive and time-consuming imaging modalities that may require ionizing radiation or intravenous contrast and undergo venography and coil embolization.