Imaging Pearls ❯ Kidney ❯ Renal Vein
|
-- OR -- |
|
- “Left renal vein (LRV) entrapment is termed nutcracker phenomenon (NCP) when asymptomatic and nutcracker syndrome (NCS) when symptomatic. The term ‘nutcracker’ is attributed to de Scheppers (1972), although Grant reported the first anatomical description (1937). A bimodal peak in the 2nd decade and 3rd to 4th decades with a female preponderance is recognized. In anterior NCS, the LRV is compressed between the SMA and aorta in the aorto-mesenteric space. In posterior NCS (20%), a circumaortic or retroaortic LRV is compressed between the aorta and the spine Predisposing factors include renal ptosis, hyperacute SMA to aorta angulation, and a high LRV course. Clinical findings include hematuria (most commonly), left flank or abdominal pain, proteinuria, orthostatic intolerance, and fatigue.”
Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review
Reshma M. Koshy et al.
Abdominal Radiology (2024) 49:1747–1761 - “May-Thurner (MT) syndrome refers to compression of the left common iliac vein (LCIV) between the right common iliac artery (RCIA) and the lumbar spine (typically at the L5 vertebra level). Virchow (1851) reported a link between this anatomic variation and an increased incidence of left leg deep venous thrombosis (DVT). May and Thurner (1957), for which MT syndrome is eponymously named, discovered MT anatomy with intraluminal venous spurs in 22% of 430 cadavers. These spurs are secondary to chronic pulsations and mechanical stress by the RCIA resulting in venous endothelial damage and intimal fibrosis. There is a female-to-male ratio of 5:1 with most patients being in the 2nd to 5th decade Females are disproportionately affected due to their more accentuated lumbar lordosis leading to reduced pelvic space. MT anatomy predisposes to venous hypertension and recurrent left limb DVT, with MT accounting for 2–5% of all DVTs. Most patients (70%) with MT anatomy are asymptomatic.”
Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review
Reshma M. Koshy et al.
Abdominal Radiology (2024) 49:1747–1761 - “MT anatomy is associated with three morphological appearances as originally described by Jeon et al. on CT venography including (a) focal extrinsic compression, (b) diffuse atrophy, and (c) cord-like obliteration. In (a), there is focal extrinsic compression of the LCIV by the crossing RCIA. In (b), there is a contiguous stenotic segment of the LCIV between the compression site superiorly and the internal and external iliac bifurcation distally. In (c), the contiguous stenotic segment of the LCIV becomes more profoundly narrowed and diffusely thread-like. These morphologic appearances presumably represent a continuum of vessel alterations over time. CT/MR can confirm MT anatomy, assess the degree of obstruction, and evaluate for DVT, pulmonary emboli, and other abnormalities such as dilated retroperitoneal or pudendal venous collaterals, and lower limb edema from venous congestion. Thin collimationand multiplanar reconstructions improve the conspicuity of findings and anatomical relationships.”
Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review
Reshma M. Koshy et al.
Abdominal Radiology (2024) 49:1747–1761 - “Crossing vessels (CVs), first described by Wadsworth (1983), are a potential extrinsic cause of ureteropelvic junction obstruction (UPJO). CVs are commonly renal arteries or veins located at the ureteric transition point, with the lower pole anterior segmental artery or vein most frequently implicated. In UPJO, CVs are found in 45–51% of adults and older children, and in 6–11% of younger children. A histopathology study of 178 patients showed that chronic inflammation was more common in UPJs related to CVs than UPJs from intrinsic etiologies (e.g., a congenitally stenotic or aperistaltic proximal ureter that typicallymanifests as antenatal hydronephrosis). Intermittentobstruction is characteristic with symptoms including abdominal pain, hematuria, vomiting, and infection.”
Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review
Reshma M. Koshy et al.
Abdominal Radiology (2024) 49:1747–1761
- Renal Vein Thrombosis: Causes
- Primary hypercoagulability disorders (e.g., antithrombin III deficiency, protein C or S deficiency, factor V Leiden mutation, prothrombin G20210A mutation)
- Antiphospholipid syndrome
- Postrenal transplant/allograft rejection
- Renal vasculitis
- Sickle cell nephropathy
- Systemic lupus erythematosus (SLE)
- Amyloidosis
- Diabetic nephropathy
- Trauma
- Renal tumors extend into the RV (RCC, TCC) - Renal Vein Thrombosis: Facts
- Renal vein thrombosis (RVT), the presence of thrombus in the major renal veins or its tributaries, is a rare clinical entity.
- Males are affected more commonly than females with no racial predilection.
- Clinical manifestations vary by the rapidity of the venous occlusion.
- The most common etiology is nephrotic syndrome, though can be seen with primary hypercoagulability disorders, malignant renal tumors, infections, trauma, or as a post-renal transplant complication.
- “About 30% of individuals demonstrate more than 1 branch of the right renal vein. In about 6% of individuals, the right adrenal gland vein drains into the right renal vein, which reflects the normal anatomy on the left side. Retroperitoneal veins, such as lumbar veins, drain into the right renal vein in about 3% of individuals.”
Recent Innovations in Renal Vascular Imaging
Arash Bedayat et al
Radiol Clin N Am 58 (2020) 781–796
- Renal Vein Thrombosis: Facts
- may be accompanied in 15–20 % of patients by nephrotic syndrome
- RVT is associated with abdominal surgery, including laparoscopic cholecystectomy, trauma, tumor invasion of the renal vein or invasion by primary retroperitoneal diseases. - “CT is currently the imaging method of choice for diagnosing RVT, as it is non-invasive, is somewhat less expensive than other methods, can be performed quickly, and has a high diagnostic accuracy. CT scans have shown high sensitivity (92 %) and specificity (100 %) in diagnosing these lesions and is therefore recommended as an initial diagnostic tool .”
Renal vein thrombosis mimicking urinary calculus: a dilemma of diagnosis
Yimin Wang et al.
BMC Urol. 2015; 15: 61 - RVT may be diagnosed incorrectly as renal colic or renal cell carcinoma on abdominal ultrasonography. Results in our patients showed that a calcified RVT may mimic a urinary calculus on conventional ultrasonography, abdominal plain film and noncontrast CT. Renal stones may also resemble paragonimus calcified oval, renal artery aneurysms and acute renal infarctions. Thus, awareness of the conditions that could mimic those observed during the generation of a urinary calculus is important, particularly if a percutaneous procedure is considered. Ultrasonography alone is not sufficient to rule out RVT in these patients, suggesting the need for CT angiography in evaluating our patients.
Renal vein thrombosis mimicking urinary calculus: a dilemma of diagnosis
Yimin Wang et al.
BMC Urol. 2015; 15: 61 - Renal Vein Thrombosis
- Renal Vein Thrombosis: Etiologies
- Renal cell carcinoma
- Transitional cell carcinoma
- Extra-renal tumors including adrenal cancer
- Leiomyosarcoma of the renal vein (primary)
- trauma
- “The clinical and radiologic signs associated with RVT vary with the acuity of onset and amount of thrombus within the renal vein. Typical symptoms and signs include flank pain, microscopic hematuria, and deterioration of renal function. The most common causes for RVT are extension of renal tumor, trauma, or a hypercoagulable state as seen in nephrotic syndrome (ie, membranous
glomerulonephritis), systemic lupus erythematosus, or an inherited syndrome. Renal vein thrombus occurs in 20% of patients with nephrotic syndrome .”
Acute Urinary Tract Disorders Goel RH et al. Radiol Clin N Am 53 (2015) 1273–1292 - “RVT is more common on the left, because of the longer course of the left vein. CT imaging findings include filling defect in the renal vein, enlarged kidney with extension of edema into the sinus and perinephric fat, and coarse striations. In contrast to bland thrombus, tumor-related thrombus heterogeneously enhances and distends the vein .”
Acute Urinary Tract Disorders Goel RH et al. Radiol Clin N Am 53 (2015) 1273–1292
- Renal AV Malformations: Facts
- Very rare CT findings
- Usually congenital but may be due to underlying tumor
- May be large (aneurysmal) and solitary or numerous and small (cirsoid type). Cirsoid type more common.
- Usually located in renal sinus
- Usually solitary and right sided
- Presentation may be gross hematuria, hypertension, flank pain and high cardiac output failure - Renal Veins: Pathologies
- Renal vein thrombus
- Rein vein tumor thrombus
- Spontaneous splenorenal shunt
- Nutcracker syndrome
- Renal varix
- AV malformation
- Renal Veins: Pathologies
- Renal vein thrombus
- Rein vein tumor thrombus
- Spontaneous splenorenal shunt
- Nutcracker syndrome
- Renal varix
- AV malformation
- Renal Veins: Facts
- Left renal vein is 3x larger than the right renal vein (7.5 cm vs 2.5 cm)
- Multiple renal veins in up to 30% of patients
- Left renal vein variations include retro-aortic renal vein and circumaortic renal vein
- Left renal vein receives the left adrenal vein, left gonadal vein, and a lumbar vein - Renal Veins: Pathologies
- Renal vein thrombus
- Rein vein tumor thrombus
- Spontaneous splenorenal shunt
- Nutcracker syndrome
- Renal varix
- AV malformation - Renal Vein Thrombus: Etiologies
- Glomerulonephritis
- Collagen vascular disease
- Trauma
- Malignancy
- Dehydration (children)
- Sepsis (children) - Renal Vein Thrombus: CT Findings
- Partial or total thrombus in the renal vein
- More common in left renal vein
- Vein may be distended
- Enlarged kidney
- Delayed or persistent CT nephrogram
- Collaterals around kidney (“cobwebs”) - Renal AV Malformations: Facts
- Very rare CT findings
- Usually congenital but may be due to underlying tumor
- May be large (aneurysmal) and solitary or numerous and small (cirsoid type). Cirsoid type more common.
- Usually located in renal sinus
- Usually solitary and right sided
- Presentation may be gross hematuria, hypertension, flank pain and high cardiac output failure