Chyluria: non-enhanced MR lymphography

Abstract

Chyluria is an uncommon medical condition resulting from an abnormal communication between the abdominal lymphatic system and the urinary tract, which results in the presence of chyle in the urine, making it appear milky white. Proper diagnosis is demonstrated by the concentration of urinary lipids. Worldwide, chyluria is most commonly associated with the parasite Wuchereria bancrofti. However, in Europe and North America, where the condition is rare, non-parasitic etiologies predominate. Identifying the cause and location of the uro-lymphatic communication is essential in guiding therapeutic management, but imaging the lymphatic channels remains a challenge. Magnetic resonance (MR) lymphography, a non-invasive free-breathing 3D high-resolution fast-recovery fast spin-echo sequence similar to that used for 3D MR cholangiopancreatography, may demonstrate the cause and location of an abnormal communication between the lymphatic system and urinary tract. In parasitic causes of chyluria, dilated lymphatics vessels communicating with the lymphatic system are demonstrated. In non-parasitic causes of chyluria channel type lymphatic malformations are the most common. Markedly dilated and dysplastic lymphatic vessels communicating with the urinary tract are demonstrated. In addition, other cystic or channel type lymphatic malformations such as thoracic, soft tissue or bone abnormalities may be observed. This review describes the abdominal lymphatic diseases leading to chyluria and presents the technique and images obtained with non-enhanced MR lymphography to enable radiologists in identifying and classifying uro-lymphatic fistulae.Critical relevance statement: Non-enhanced MR lymphography enables the identification and categorization of uro-lymphatic fistulae. Graphical abstract

Central Lymphatic Imaging in Adults with Spontaneous Chyluria

“…This enables a much swifter visualization of lymphatic branches compared to imaging with oil-based contrast agents. 8 In our study, all patients undergoing MRL exhibited a clear visualization of the thoracic duct without anatomical variations. Dilatation of the thoracic duct was observed in 76.7% of patients (n=33), and uro-lymphatic fistula was seen in 83.7% (n=36) of patients as lymphatic branches entering the renal hilum (Figure 1).…”

“…These findings are consistent with recent studies on MRL imaging in chyluria. 7,8,11 In terms of MRL techniques, there are currently two main approaches: one utilizing contrast agents injected into the inguinal lymph node (MR lymphangiography) and the other employing non-enhanced magnetic resonance lymphography. Both methods aim to reveal the communication between the lymphatic and urinary systems.…”

“…Sabbah et al conducted MR lymphography on a 3Tesla machine, demonstrating a clear depiction of communication between the lymphatic and urinary systems, accompanied by the consistent dilation of lymphatic vessels at the fistula site. 8 The advantages of MRL are evident in the higher number of patients with TD visualization compared to IL using oilbased contrast agent. The group of patients using oil-based contrast agent only had 51% TD visualization compared to 100% in the MRL group (Table 3).…”

“…Then, under MRI or fluoroscopy, the contrast depicts the abnormal lymphatic branches that connect with the urologic system. 8,9 So far, there have been few studies of the central lymphatic system in patients with chyluria. This study, with the largest number of patients, focuses on analyzing images of the major lymphatic vessels in patients with spontaneous chyluria.…”

Renal pedicle lymphatic ligation for non-parasitic chyluria via retroperitoneal laparoscopic surgery: a single-center 12-year experience

“…Chyluria is a rare condition in which chyle is excreted in the urine ( 13 ). Chyluria is often caused by pathological changes in lymphatic system dynamics, such as filarial infection, abdominal or retroperitoneal tumors, tuberculosis, and trauma ( 15 ), which eventually lead to an increase in lymphatic pressure, and consequently, the formation of chyle in the urine due to the abnormal communication of a fistula between the lymphatic vessels and the tract of urinary ( 3 , 16 ). Due to a large loss of protein and fat in the urine, non-parasitic chyluria patients often present with hypoproteinemia, malabsorption, general fatigue, and weight loss.…”