Diagnostic value of computed tomographic findings of nutcracker syndrome: Correlation with renal venography and renocaval pressure gradients

Department of Radiology, Seoul National University Hospital, and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
European journal of radiology (Impact Factor: 2.37). 12/2011; 80(3):648-54. DOI: 10.1016/j.ejrad.2010.08.044
Source: PubMed


To evaluate the diagnostic values of CT findings of nutcracker syndrome (NCS).
Twenty seven subjects that underwent CT and renal venography, were divided into three groups based on the venographic renocaval pressure gradient (PG) and collateral veins of the left renal vein (LRV): non-compensated NCS patients with PG≥3 mm Hg (group 1, n=12), partially compensated NCS patients with borderline PG (1<3 mm Hg) and collateral veins (group 2, n=6), and control group with low PG (0-1 mm Hg) without collateral veins (group 3, n=9). The CT findings were analyzed with regard to abrupt narrowing of the LRV with an acute angle (beak sign), aortomesenteric angle between the superior mesenteric artery and aorta on sagittal images, and LRV diameter ratio (hilar-aortomesenteric).
Beak sign of the LRV was found in 91.7% (11/12) of group 1, 50% (3/6) of group 2, and in 11.1% (1/9) of group 3 with the significant difference between groups 1 and 3 (P<.05, χ2 test). Mean values of all quantitative CT parameters differed significantly only between groups 1 and 3 (P<.05, one-way ANOVA test). For differentiating the non-compensated NCS from the control group, the beak sign showed 91.7% sensitivity and 88.9% specificity. Of the various CT parameters, the beak sign and LRV diameter ratio of ≥4.9 showed the greatest diagnostic accuracy (AUC 0.903, ROC analysis).
Beak sign of the LRV and CT findings can be useful in diagnosing the non-compensated NCS.

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    • "The normal angle between the SMA and the abdominal aorta is approximately 90° (3). The decreased angle between SMA and the aorta can cause NCS, this angle was reported as 39.3° ± 4.3° by Kim et al. and Fu et al. (4, 5). In our case, the angle between the aorta and the SMA was approximately 14.5°, which is nearly the lowest angle in comparison with previous studies and reported cases in the literature. "
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    ABSTRACT: Nutcracker syndrome (NCS) is a rare pathology, caused by compression of the left renal vein (LRV) between the abdominal aorta (AA) and the superior mesenteric artery (SMA), due to reduction of the angle between AA and SMA. This leads to LRV varices, left gonadal vein varices and therefore, the pelvic congestion syndrome. For this reason, coexistence of NCS and pelvic congestion syndrome has been described. It manifests by hematuria, proteinuria, and nonspecific pelvic pain secondary to pelvic congestion, dyspareunia and persistent genital arousal. We report a 27-year-old woman who experienced hematuria and left flank pain. The diagnosis of NCS accompanied by pelvic congestion syndrome was missed initially, but later on the diagnosis was made by color Doppler ultrasound, abdominal computed tomography (CT) and CT angiography that were later performed. She refused interventional and surgical treatments, and was lost to follow up. Implication for health policy/practice/research/medical education: Nutcracker syndrome accompanying pelvic congestion syndrome is a rare, but treatable clinical condition. Inclusion of this entity in the differential diagnosis of patients with an unknown cause of hematuria and flank pain can achieve efficient management of this condition. In addition, in our case, the angle between the aorta and the superior mesenteric artery was approximately 14.5 degrees, which is almost the lowest angle in comparison with previous studies and reported cases in the literature.
    Full-text · Article · Jun 2014 · Iranian Journal of Radiology
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    • "The radiological evaluation plays a critical role in the diagnosis of NCS, and has been considered as an essential method in clinical intervention in NCS. However, most of the studies have focused on the diagnostic value of different imaging methods in NCS [1],[2],[3],[4],[5],[6],[7]. There is a lack of studies investigating the hemodynamic changes following LRV compression, or evaluating the perfusion level and renal functions. "
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    ABSTRACT: To investigate the relationship between the level of left renal vein (LRV) compression and changes in the perfusion of the left kidney in patients with nutcracker syndrome (NCS) by one-stop whole-organ perfusion imaging of bilateral kidneys using 640-slice volume CT. Twelve patients, clinically diagnosed with NCS, were subjected to one-stop examination of kidneys. Angiography and whole-organ perfusion imaging of bilateral kidneys were conducted, and the compression segment of LRV was demonstrated and measured. Information including the results of whole-organ perfusion images of both kidneys in 12 patients was collected. Results of epigastrium dynamic volume scanning by 640-slice volume CT were collected for 12 patients as control group. Left and right renal cortexes were chosen as regions of interest (ROI), and their perfusion values were measured. The perfusion values of the left and right renal cortexes in the control group were 323.8 ml·min(-1)·100 ml(-1) and 322.9 ml·min(-1)·100 ml(-1), respectively. The difference was not statistically significant (t = 1.388, P = 0.193). For NCS patients, the perfusion values of the left and right renal cortexes were 350.8 ml·min(-1)·100 ml(-1) and 391.1 ml·min(-1)·100 ml(-1), respectively. Significantly decreased value was observed in left renal cortex compared to that of the right renal cortex, with the mean decrease of 40.3 ml·min(-1)·100 ml(-1), and the difference was statistically significant (t = -4.204, P = 0.001). As a non-invasive functional imaging technique, whole-organ perfusion imaging of kidneys can be used to evaluate the organ and tissue perfusion status and to accurately reflect the hemodynamic changes of the left renal cortex in the patients with NCS. Whole organ perfusion imaging may also provide the basis for quantitative diagnosis and clinical interventions of NCS.
    Preview · Article · Sep 2013 · PLoS ONE
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    ABSTRACT: The nutcracker syndrome is defined by the compression of the left renal vein between the aorta and superior mesenteric arteries, accompanied by a classic, but less specific, symptomatology. We reported a case of a 37-year-old woman who had been investigated because of intermittent gross hematuria of unknown origin. Computed tomographic angiography revealed compression of the left renal vein as it ran between the superior mesenteric artery and the abdominal aorta, associated with significant dilation of the left ovarian vein. The nutcracker syndrome, caused by compression of the left renal vein by the aorta and superior mesenteric arteries, is probably more prevalent in women, and it is caused by specific situations, such as renal ptosis and paucity of retroperitoneal fat. Hematuria, a typical symptom, is due to rupture of the thin-walled septum separating the veins of the urinary collecting system. Imaging tests may help with the diagnosis. The best treatment is still elusive, but there are several surgical approaches, such as intravascular stenting, and also a conservative management. Diagnosis is usually delayed, and the syndrome should be included in the differential of hematuria of unknown origin.
    Preview · Article · Jun 2012 · Jornal Brasileiro de Nefrologia
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