This prospective study included 25 women with a mean age of 48.67 ± 12.34 (range 34–55) who were referred to the radiology department with clinical and US features suggesting PCS, in the period from April/2019 to April/2020. At the time of patient hospital admission, comorbidities, as well as standard physical examination findings, were recorded.
The clinical evaluation included a history of congestion symptoms and a physical examination of the pelvic region and the lower limbs to demonstrate signs of venous incompetence or obstruction. This included four clinical presentations (a) chronic pelvic pain of at least 6 months; (b) venous claudication due to iliac venous obstruction; (c) left flank or abdominal pain and hematuria due to left renal vein compression; and (d) symptomatic lower extremity varicosities in either atypical (vulva, medial, and posterior thigh, sciatic nerve) or typical saphenous distributions.
Any patient with general contra-indications to MRI as the presence of any paramagnetic substance as pacemakers, or in severely ill patients or those with claustrophobia, arrhythmic patients (that were managed by pacemakers) were excluded from the study that has a pacemaker. The study was conducted after approval of the institutional Ethical Committee, and informed written consent was obtained from each participant.
MRI, and TR-MRV
The MRI examinations were performed with a 1.5 T imaging unit (Magnetom Sempra, Siemens, Erlangen, Germany) with the use of a body phased-array coil. Preliminary sequences covering the abdomen and pelvis from the upper pole of the left kidney to the proximal thighs were performed for all patients. These included axial, coronal, and sagittal T2-weighted turbo spin-echo (T2_TSE) images and axial T1-weighted fast low angle shot (FLASH) images to examine the pelvic organs and detect dilatation of the pelvic veins. The T2_TSE sequence was performed with the following parameters: repetition time (TR)/echo time (TE) 3570/100 ms; field of view of 210 mm; flip angle 150 and slice thickness of 4 mm. T1_FLASH sequence was performed with the following parameters: TR/TE of 185/5 ms; field of view 360 mm; flip angle 70 and slice thickness 6 mm.
MRV with TRI was then performed for the detection of venous reflux. The acquisition parameters of TR-MRA were the following: TR/TE of 5.5/1.5 ms, flip angle 25, slices/slab 70, slice thickness 1 mm, and field of view 360 mm. Four phases (arterial, late arterial, venous, and late venous) were performed in the coronal plane during shallow breathing for 2 min after iv injection of 0.1 mmol/kg bodyweight of contrast medium gadopentetate dimeglumine (Magnevist, Schering, Berlin, Germany), at a rate of 2 ml/s which was followed by a 20 ml saline flush. To achieve maximum contrast signal in the veins, the transit time of the contrast medium was determined with the use of a bolus tracking technique initiated by abdominal aortic enhancement at the renal artery level. The acquisition time per phase was 20 s, and the intervals between phases were 5 s. The post-enhanced MR images for each phase were subtracted from the pre-contrast MR image and used to generate MRV. The images are then post-processed using maximum intensity projection (MIP) algorithms.
Finally, a post-contrast axial 3D fat-suppressed T1-weighted (T1_VIBE) sequence covering the abdomen and pelvis was performed with the following parameters: TR/TE of 5.82/2.35 ms; field of view 320 mm; flip angle of 10 and slice thickness of 3 mm.
Venography was performed using the Artiszee-Siemens Healthcare Angiography system. With the patient in a supine position, venographic access was obtained with the Seldinger technique via the right femoral vein or the right internal jugular vein. Catheterization of the inferior vena cava was done using a 5-French Cobra catheter (Cook, Bloomington, IN), and bilateral venography of the common iliac vein, external iliac vein, and a selective internal iliac vein was performed to evaluate for reflux in the internal iliac veins and narrowing of the left common iliac vein in May–Thurner syndrome. Venography of the left renal vein was then performed to detect nutcracker syndrome or reflux into the left ovarian vein. If reflux is seen in the ovarian vein, the catheter was positioned in the proximal part of the vein and selective venography was performed to detect reflux into the visceral venous plexus and bridging arcuate uterine veins to the contralateral side. Finally, a contrast medium is injected into the inferior vena cava to detect incompetence of the right ovarian vein and selective right ovarian vein venography was performed if needed.
At the end of the examination, patients were observed for about 4 h and then discharged home.
MRI and MRV with TRI were interpreted first in a prospective and blinded manner by two radiologists with 15 and 20 years of experience, and diagnosis was made in consensus. Conventional venography was used as the standard of reference. For the analysis, the venous system was divided into the following segments: the common and internal iliac veins, the ovarian veins, and the pelvic plexus.
Demonstration of the venous anatomy on TRI was assessed as either inadequate (impossible to definitively determine a treatment plan), sufficient (intermediate image quality but sufficient for treatment planning), or excellent anatomic visualization.
The diagnostic criteria for pelvic venous incompetence on MRV with TRI were the retrograde caudal flow of contrast material, dilated para-uterine varices, the presence of an arcuate vein crossing the midline, heterogeneous or T2-hyperintensity due to slow flow, vulvar and/or thigh varices, polycystic ovarian configuration and the absence of an obstructing mass or structural obstruction.
The diagnostic criteria for pelvic venous incompetence on venography were dilated gonadal, uterine, and utero-ovarian arcade veins > 5 mm in diameter, retrograde caudal flow in the ovarian vein (unilateral or bilateral), reflux of contrast material across the midline to the contralateral side through the utero-ovarian arcade, retrograde filling of the principal tributaries of the IIV (gluteal, sciatic, obturator vein) and stagnation of contrast material in pelvic veins . May–Thurner Syndrome was diagnosed by compression of the left common iliac vein by the right common iliac artery.
All statistical tests were performed using IBM-SPSS 23.0 (IBM-SPSS Inc., Chicago, IL, USA). Continuous data were expressed in mean and standard deviation while categorical data were expressed in count and percentage. Weighted k statistics were calculated to assess the interobserver agreement for correctly identifying all the refluxing veins by TRI in each patient. The level of agreement was defined as follows: k-values of 0.00–0.40 indicated poor agreement, k-values of 0.41–0.75 indicated good agreement, and k-values of 0.76–1.00 represented excellent agreement.