This is an interesting case involving a 46 year old female who had an acute onset of right lower extremity pain within the previous 18 hours. She had had a cardiac cath and coronary angiogram 2 weeks earlier and subsequently developed right lower extremity weakness and increasing intermittent claudication leading up to the present episode. The Vascular Surgeon (MG) elected to evaluate the extent of her post-angio occlusion with an MRA scan to avoid another catheterization to which the patient was adamantly opposed. With the current quality of available MRA this is most certainly an acceptable option. The 2D Time Of Flight (2D TOF) MRA of the pelvis is shown in Figure 1.
The occluded right common femoral artery is well demonstrated in this angled left anterior oblique view. The most interesting part of the case now became the vascular structure in the patient’s LEFT pelvis and abdomen. The structure follows the course of the left ovarian vein and in conjunction with the demonstrated pelvic varicosities in the area of the left ovary, an A/V malformation was postulated. The difficulty with that diagnosis, was that the phase encoding to visualize the arteries is employed precisely to render veins invisible to the scanner and if this were a vein, why was it visible? A GYN Consultant opined that A/V flow like this could be seen in cancer of the ovary. That certainly could explain the presence of the vessel except for the fact that it ought not be visible if flow were from the pelvis to the renal vein.

Still avoiding an A-gram, a CT scan was done (Fig. 2). This scan clearly showed the contrast filled vessels in the left pelvis, in the left flank and included the left renal vein, which is scissored between the superior mesenteric artery and aorta the so-called ”renal vein nutcracker syndrome” initially described by deSchepper in the Journal Belge de Radiologie (55:507-11,1972). The configuration explained why the vessel was bright on MRA since the flow was from the renal vein towards the pelvis. The beaded appearance is explained by the relatively slow flow in the vein which allowed increased MRA saturation (brightness) nodes between signal detections; not uniformly bright as in the much faster flowing arteries.

Since the specter of malignancy had been raised, a retrograde left gonadal venogram via the left renal vein confirmed the diagnosis of reversed flow from the renal vein (Fig.3). The gonadal venogram showed not only the direction of flow as seen on the MRA but effectively removed malignancy from the working differential. It also showed the reasons for the pelvic venous dilation, far in excess of that usually seen in this situation. The retrograde flow was initiated by the proximal nutcracker obstruction but the markedly dilated and redundant pelvic varicosities were caused by the distal compression of the left iliac vein as it crossed the right common iliac artery (described eons ago by the British Radiologist M. Lea Thomas) forcing left to right pelvic venous cross circulation. This was responsible for the appearance of the suspected pelvic A/V malformation on original MRA.

Follow-up: The patient had successful right common femoral thrombectomy and vein patch (MG) with normalization of right leg flow but had persistent symptoms of “pelvic congestion”. She very astutely visited the INTERNET and found the Radiologist who has written most about A/V malformations, Bob White, formerly at Johns Hopkins; now Chairman at Yale. She opted to travel there to have the simple procedure and did have the ovarian vein embolized without apparent immediate problems up to the present.

This case is presented as informational only for reasons which will become apparent: 1st as an extremely interesting sequence of events in an unusual presentation of a common entity -- retrograde gonadal and/or ascending lumbar vein flow from proximal renal vein compression, albeit usually from retro-aortic position or aortic dilation; 2nd compression of the left iliac vein forcing cross pelvic flow instead of the more usual ipsilateral hypogastric to common iliac to IVC return; 3rd patients now know where to look for medical information and are willing to travel, sometimes even long distances, for treatment based on what they perceive as their best option even if equivalent or superior opportunity or advice exists locally; and 4th further verification of the past few month’s hottest topic – “Elevator Conversations”.

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