Diagnosis Of Nutcracker Syndrome Research Articles

The superior mesenteric artery angle in diagnosis of nutcracker syndrome: a systematic review and meta-analysis.

Nutcracker syndrome (NCS) can be caused by narrowness of the superior mesenteric artery (SMA) angle. Nevertheless, the cut-off value of the SMA angle is controversial and variable. Therefore, the present study evaluated the optimal SMA angle to maximize diagnostic performance for NCS diagnosis by conducting a meta-analysis. We comprehensively searched the English literature related to the diagnosis of NCS from the perspective of SMA (from the date of database inception to June 2022). The accuracy of an SMA angle less than 41° in the diagnosis of NCS was evaluated by calculating the pooled sensitivity (SEN), pooled specificity (SPE), positive likelihood ratio (LR+), negative likelihood ratio (LR-), summary receiver operating characteristic (SROC) curve and area under the curve (AUC) value. The I2 test and meta-regression analysis were used to assess heterogeneity and sources of heterogeneity, respectively. Publication bias was assessed using Deeks' funnel plot asymmetry test. Six studies (526 patients) met the inclusion criteria. SEN and SPE were 0.94 (95% confidence interval (CI) 0.80-0.99) and 0.85 (95% CI 0.65-0.94), respectively. The LR + value was 6.0, and the LR- value was 0.07, revealing that SMA angles less than 41° exhibited an excellent ability to help confirm or exclude NCS. Additionally, SROC curves showed that the AUC of SMA angles less than 41° for the diagnosis of NCS was 0.96, indicating that SMA angles less than 41° have good efficacy for helping to diagnose NCS. This study explored the diagnostic efficacy of the cut-off value of the SMA angle by meta-analysis. According to the high SPE and SEN results, SMA angles less than 41° have good efficacy in facilitating NCS diagnosis.

Trampolinspringen-induzierte Makrohämaturie

Es wird über den Fall eines 12-jährigen Jungen mit sportinduzierter, rezidivierender Makrohämaturie und linksseitigen Flankenschmerzen berichtet. Nach umfangreicher laborchemischer sowie bildgebender Diagnostik wird in Zusammenschau des charakteristischen klinischen Bildes die Diagnose Nussknackersyndrom gestellt. Unter konservativen Maßnahmen sowie Verzicht auf den auslösenden Sport kam es zu einer klinischen sowie bildmorphologisch bestätigten Maturation.

The utility of magnetic resonance angiography in children with nutcracker syndrome

Background/aim The presented study aimed to evaluate the utility of magnetic resonance angiography (MRA) in the pediatric population with nutcracker syndrome.Materials and methods Patients with suggestive clinical symptoms and laboratory findings and got the diagnosis of nutcracker syndrome with Doppler ultrasonography between January 2011–2019 were included in the study. In addition, children who had renal MRA due to hypertension were evaluated as the control group. MRA images of all patients were examined retrospectively by three radiologists at different levels of experience, and the superior mesenteric artery angle, aorta-mesenteric distance, left renal vein diameter both in the regions of aorta-mesenteric, and renal hilum were recorded. ResultsForty-five patients diagnosed with nutcracker syndrome were included in the study. The mean age of patients was 12 (4–16) and 30 (67%) were female. As the control group, 25 patients with hypertension who had MRA were included and they had a mean age of 12 (1–18) and 19 (76%) were male. The mean superior mesenteric artery angle was 26.5 ° (16–73 ± 12) in the patient group and 57.8 ° (25–139, ± 33) in the control group (p < 0.001); the mean aorta-mesenteric distance was 3.3 mm (1.7–6.5, ± 1.1) in the patient group and 8 mm (3.4–32, ± 5.9) in the control group (p < 0.001). MRA measurements of three radiologists were consistent with each other.ConclusionMRA imaging can be applied as an alternative diagnostic method for Doppler ultrasonography and multidetector CT examinations by radiologists with different experience levels in pediatric patients with nutcracker syndrome.

Diagnosis and treatment in children with Nutcracker Syndrome: Single-center experience

Objective: It has been aimed to report the experience of our center regarding diagnosis and treatment experience in children with Nutcracker syndrome (NCS). Materials and Methods: The medical records of the seven patients who have admitted to the Department of Pediatric Nephrology of our hospital between February 2017 and March 2020 were evaluated retrospectively. The diagnosis of NCS was confirmed with renal Doppler ultrasound (RDUS) and magnetic resonance angiography (MRA) in these patients who have admitted with the complaints of hematuria and proteinuria. The patient data such as clinical characteristics, radiological findings, radiological signs and information about the applied medical treatment at baseline and the last control examination were recorded. Results: The mean levels of 24-h urine protein excretion in all the patients at baseline and the last control examination were 15,25±9,19 mg/m2/h and 9,8±3,94 mg/m2/h, respectively. The mean levels of 24-h urine protein excretion in the patients treated with ACE (angiotensin converting enzyme) inhibitor at baseline and the last control examination were 20±11,53 mg/m2/h and 9,6±6,44 mg/m2/h, respectively. (p=0,073). The mean levels of 24-h urine protein excretion were 11.7±6.39 mg/m2/h and 9.95±1.84 mg/m2/h in the patients not receiving ACE inhibitor treatment, at baseline and the last control examination respectively (p= 0,61). The mean angle value of the left renal vein in the aortomesenteric distance measured by RDUS examination performed in the upright position was 14,71±4,46 degrees. The anteroposterior diameter of the left renal vein (hilar/aortomesenteric) measured in the upright position was 6,4. Conclusion: The benign nature of NCS in young patients requires maintaining conservative approach.

Value of magnetic resonance imaging indices of left renal vein entrapment in the diagnosis of nutcracker syndrome in children.

BackgroundNutcracker syndrome (NCS) is also known as left renal vein (LRV) compression syndrome. Magnetic resonance imaging (MRI) can better depict the anatomical structure of soft tissues in the area of compression. Diagnosis of NCS using MRI in adults is not uncommon. However, there are few studies on the diagnosis of NCS using MRI in children. Therefore, we conducted this study to evaluate the clinical value of the MRI indices of the LRV in the diagnosis of NCS in children.MethodsThis study was a single-center retrospective analysis. One hundred seventy-four patients with suspected NCS were enrolled from January 2017 to July 2020. The inclusion criteria for suspected NCS were mainly based on clinical symptoms or signs, laboratory examinations and imaging reports. Other diseases that may cause hematuria and/or proteinuria were excluded. We grouped the patients based on the diagnostic criteria for NCS into a nutcracker group and a control group. The receiver operating characteristic (ROC) curve was constructed for evaluating the value of MRI indices in the diagnosis of NCS.ResultsThe majority of NCS patients presented with orthostatic proteinuria (OP) (67.2%), followed by hematuria (55.2%), abdominal pain (19.0%), and left flank pain (15.5%). The areas under the curve (AUCs) for the superior mesenteric artery (SMA) angle, beak sign, and compression ratio (CR) in the diagnosis of NCS were 0.870, 0.895, and 0.878, respectively, and the best cutoff values of the SMA angle and CR were 36.8 and 3.99, respectively. The specificities of SMA angle <36.8°, beak sign, CR >3.99, SMA angle <36.8° and beak sign, SMA angle <36.8° and CR >3.99, and beak sign and CR >3.99 were 82.5%, 93.8%, 93.8%, 97.9%, 95.9% and 97.9%, respectively.ConclusionsChildren with SMA angles less than 36.8°, beak signs and CR greater than 3.99 should be highly suspected of having NCS. Among these parameters, “beak sign” showed the highest diagnostic accuracy by MRI, and the combination of any two of the above parameters achieved a higher specificity than the single parameters.

NUTRACKER SYNDROME

In the nutcracker anatomy, the aortomesenteric angle is more acute, which leads to a compression of the left renal vein between the aorta and the superior mesenteric artery. As a result, there is an impended outflow of the left renal vein in the inferior vena cava. This is termed as nutcracker syndrome.&nbsp; Complex of clinical symptoms exists in the nutcracker syndrome (NS). Nutcracker phenomenon (NP) is the term used to describe an anatomic finding without any clinical symptoms. The aim of this case study was to show the use of a multiphase computed tomography as a diagnostic method of choice in dealing with cases of nutcracker anatomy in patients. We present four cases of patients who underwent computed tomography of the abdomen. Two of the cases were with anterior nutcracker syndrome, one case was with posterior nutcracker syndrome and one case with nutcracker phenomenon. Establishing of the exact diagnosis in these patients is difficult, because of the rarity and variety in symptoms. Existence of the clinical symptoms distinguishes whether the patient has NS or NP. Multiphase CT scan of the abdomen with additional reconstructions in maximum intensity projection (MIP), volume rendering (VR) and multiplanar reconstruction (MPR) as an imaging method is the method of choice in the diagnosis of NS and NP. Keywords: nutcracker syndrome, nutcracker phenomenon, computed tomography, anatomic variations

Serial ganglion impar blocks in a patient with nutcracker syndrome refractory to left renal vein transposition: a case report

BackgroundNutcracker syndrome is a rare disorder caused by compression of the left renal vein, usually between the aorta and the superior mesenteric artery. It typically presents with left-sided abdominal pain and hematuria. Left renal vein transposition is the most commonly employed surgical technique to alleviate the compression.Case presentationA 22-year-old Caucasian man with a known diagnosis of nutcracker syndrome had undergone left renal vein transposition 1 year before presentation without any subsequent pain relief. In addition, his surgery was complicated by massive blood loss and a 1-week-long stay in an intensive care unit (ICU); as such, he was not amenable to further surgical intervention or stenting to treat his underlying pathology. His symptoms included constant sharp left-sided flank, perineal, and testicular pain. A series of ganglion impar blocks were performed every 3–4 months over the course of 5 years with substantial pain relief achieved.ConclusionsOur case report highlights a treatment option that has not yet been described for patients with pain secondary to nutcracker syndrome refractory to surgical intervention.

Eighteen years of experience with pediatric nutcracker syndrome: the importance of the conservative approach

Nutcracker syndrome (NS) defines an entity generated by the compression of the left renal vein resulting in venous hypertension, which transmitted in a retrograde direction may cause hematuria, proteinuria, and varicocele. The literature concerning exclusively pediatric patients is very rare. To report the authors' experience with pediatric NS in the last 18 years. This is a retrospective review of the patients followed up in the authors' center with diagnosis of NS based on clinical and imaging tests (ultrasound, computed tomography/magnetic resonance imaging, and phlebography). The primary outcome was the success of the conservative approach in the study patients. A total of 21 patients were diagnosed with NS and followed up for a mean period of 52.3 months (37.1-67.5). The mean age at diagnosis was 11.7 years (9.9-13.4). The most frequent symptom of presentation was hematuria in 16 patients (76.2%), being macroscopic in 75% patients and related to physical exercise in 42.9% patients. Other symptoms were left varicocele in 7 patients (33%) and proteinuria in 6 patients (28.6%). Mild to moderate cases received conservative treatment (change of physical activity, postural hygiene), which achieved resolution of symptoms in 16 patients (76.2%). Five cases (23.8%) finally needed a more aggressive approach. Two (9.5%) of them required endovascular procedures (intravascular stent in the renal vein in 1 case and embolization of the spermatic vein in 1 case); in one (4.8%) of the patients, transposition of the left renal vein and kidney autotransplantation were performed, and 2 (9.5%) of the patients with mild cases required surgical correction of the varicocele. Hematuria, usually macroscopic and related to physical exercise, is the most frequent symptom in pediatric patients with NS. The authors advocate studying the aortomesenteric junction by abdominal ultrasound in patients with varicocele or with intermittent macroscopic hematuria. Diagnosis is based on non-invasive tests; phlebography should be reserved for severe cases that require an interventionist attitude. A long period of conservative treatment is the first approach for pediatric patients with NS.

Co-occurring superior mesenteric artery syndrome and nutcracker syndrome requiring Roux-en-Y duodenojejunostomy and left renal vein transposition: a case report and review of the literature

BackgroundThe duodenum and the left renal vein occupy the vascular angle made by the superior mesenteric artery and the aorta. When the angle becomes too acute, compression of either structure can occur. Each type of compression is associated with specific clinical symptoms that constitute a rare disorder. If clinical symptoms are mild, conservative treatment is implemented. However, surgery is often the only solution that can improve quality of life and/or avoid life-threatening complications. This report describes a case of a patient with both types of aortomesenteric compression that required two separate surgeries to alleviate all symptoms.Case presentationA 20-year-old white woman presented to the Emergency Room complaining of sudden onset severe left flank and lower left quadrant abdominal pain, nausea, and vomiting. A clinical work-up revealed elevated white blood cells and hematuria. She was discharged with a diagnosis of urinary tract infection. Symptoms continued to worsen over the subsequent 2 months. Repeated and extensive clinical work-ups failed to suggest evidence of serious pathology. Ultimately, an endoscopy revealed obstruction of her duodenum, and barium swallow identified compression by the superior mesenteric artery, leading to the diagnosis of superior mesenteric artery syndrome. She underwent a Roux-en-Y duodenojejunostomy. Six weeks later she continued to have severe left-sided pain and intermittent hematuria. Venography revealed compression of the left renal vein, extensive pelvic varices, and significant engorgement of her left ovarian vein. A diagnosis of nutcracker syndrome was made and a left renal vein transposition was performed. Significant improvement was seen after 8 weeks.ConclusionsThe disorders associated with aortomesenteric compression can lead to serious symptoms and sometimes death. Diagnosis is challenging not only because of the lack of awareness of these rare disorders, but also because they are associated with symptoms that are similar to those seen in less serious diseases. Guidance for health care professionals with respect to relevant radiological and clinical markers needs to be reconsidered in order to clarify the etiology of the diseases and create better diagnostic protocols.

Nephro urology case

The Nutcracker Syndrome (NS) originates from the compression of the left renal vein in its trajectory, mostly between the aorta and the superior mesenteric artery, or less frequently between the aorta and the lumbar spine. Although asymptomatic in most cases, it can be a rare cause of hematuria. We present the case of an 11-year-old male adolescent who was referred to a Pediatric Nephrology evaluation for a two-month-long gross hematuria. The patient also had anemia without hemodynamic repercussion. After the initial work-up, it was concluded to be a non-glomerular, extra-renal hematuria. Abdominal and renal ultrasound with Doppler was normal. The abdominal and pelvic computerized angiotomography revealed, after a careful examination, the presence of NS. Due to persistent gross hematuria with the need for transfusional support, at the age 13, the patient underwent a renal autotransplantation. The diagnosis of NS is essentially clinical, imagiological and necessarily a diagnosis of exclusion. The treatment must be individualized and requires a multifactorial approach.

A rare presentation of nutcracker syndrome and it’s vascular managment

Nutcracker syndrome includes all the symptoms associated with the narrowing of the left renal vein (LRV). That narrowing occurs between the aorta and the Superior Mesenteric Artery (anterior) or vertebra (posterior). The symptoms are various and not specific but the patient sometimes presents hematuria with or without left flank pain. We report a case on a 42 years old woman, who was suffering from left flank pain for a long time aggravated during and after each pregnancy. The diagnosis of nutcracker syndrome was initially omitted. Abdominal pelvic Angio CT and venography were performed. We placed a percutaneous stent in the narrowed portion of the renal vein. The result was successful.

Discriminating renal nutcracker syndrome from asymptomatic nutcracker phenomenon using multidetector computed tomography.

To retrospectively evaluate the ability of computed tomographic (CT) findings to discriminate nutcracker syndrome (NCS) from asymptomatic nutcracker phenomenon (NCP) and to investigate the diagnostic value of CT findings in diagnosis of NCS. From January 2014 to April 2015, 216 patients who underwent initial urographic CT were included. Initially, 216 patients were categorized as "nutcracker" or "normal," based on the following CT criteria: (1) the presence of beak sign and (2) hilar-aortomesenteric left renal vein diameter ratio >4. Patients who satisfied both of these criteria were diagnosed with nutcracker. The nutcracker was then divided into "NCS" and "asymptomatic NCP" based on the presence of characteristic symptoms. CT findings in sagittal and axial scans of corticomedullary phase were evaluated. Multivariate analysis was used to identify significant factors among 30 NCS, 51 asymptomatic NCP, and 135 normal patients. Diagnostic performance and threshold using receiver operating characteristic (ROC) curve were calculated. A total of 131 males and 85 females, with mean age of 38.6years (range 18-89years), were included. Multivariate analysis demonstrated superior mesenteric artery (SMA)-aortic angle (p<0.001) and visualization of a dilated collateral vein with reflux (p=0.001) were independent factors for distinguishing NCS from asymptomatic NCP. The combination of SMA-aortic angle <25° and visualization of a dilated collateral vein with reflux provided the greatest diagnostic accuracy (area under the ROC curve, 0.841). The combination of SMA-aortic angle and visualization of a dilated collateral vein with reflux in multidetector CT can be useful to differentiate NCS from asymptomatic NCP.

A Rare Cause of Macroscobic Hematuria: Nutcracker Syndrome

Nutcracker syndrome caused by compression of the left renal vein between the abdominal aorta and the superior mesenteric artery is a rare anatomo-pathological condition. The patients have symptoms such as hematuria, proteinuria, and left flank pain. In this paper, we report a 13-year-old boy who presented with macroscopic haematuria. Routine laboratory tests for the evaluation of hematuria were normal. Abdominal computed tomography revealed that the left renal vein was compressed between the aorta and the superior mesenteric artery. A diagnosis of nutcracker syndrome was established. If Nutcracker syndrome is considered in the differential diagnosis of haematuria, it is easily diagnosed by imaging techniques. (The Me di cal Bul le tin of Ha se ki 2015; 53: 101-3)

Renal Doppler ultrasonography in the diagnosis of nutcracker syndrome.

Renal Doppler ultrasonography in the diagnosis of nutcracker syndrome.

The nutcracker syndrome: an underrecognized cause of hematuria

Nutcracker syndrome (NCS) is an uncommon cause of hematuria. It refers to the compression of the left renal vein between the aorta and superior mesenteric artery. It can cause both microscopic and gross hematuria. Hematuria may be associated with left flank pain. The diagnosis of NCS is often delayed. Most patients may have symptoms for many years and non-diagnostic evaluations before accurate diagnosis can be established. It should be included in the differential diagnosis of unexplained hematuria. The diagnosis and treatment of nutcracker syndrome are discussed. NCS is a rare but treatable clinical condition. An inclusion of this entity in the differential diagnosis of patients with unknown cause of hematuria and flank pain can achieve efficient management of this condition.

LESS Extravascular Renal Vein Stent for Treatment of Nutcracker Syndrome: Step-by-Step Technique

Background: The aim of this video is to show how to perform step-by-step technique of laparoendoscopic single site surgery (LESS) transumbilical transmesocolic approach for treatment of nutcracker syndrome. Material and Methods: An 18-year-old man with lumbar pain, hematuria, and varicocele had a diagnosis of nutcracker syndrome with computed tomography scan. Surgical Steps: The patient was positioned in left lateral decubitus. Then, the following were performed: 3-cm intraumbilical incision; location of Alexis retractor; adaptation of surgical glove with two 10-mm trocars and one 5-mm trocar attached to Alexis; pneumoperitoneum with 15-mm CO2 pressure; identification of aortic pulsation; opening posterior peritoneum between duodenum and inferior mesenteric vein (IMV) with harmonic scalpel and conventional instruments; ligation and division of IMV; dissection of aorta until identification of obliterated renal vein, superior mesenteric artery (SMA), and dilated tributary veins; external suture passed in the mesentery of transverse colon to superior retraction; ligation and division of adrenal and gonadal veins with hem-o-lock clips; renal vein repair with Penrose drain; circumferential release of renal vein out of fibrotic adherence until vena cava; immediate observation of renal vein outflow restoration; measuring the length of renal vein to receive the external prosthesis; locating polytetrafluoroethylene (PTFE) tube around renal vein; fixation of the mesh in adventitia of aorta with 4-0 prolene attached with hem-o-lock clips; endoscopic confirmation of the correct placement of mesh related to vena cava, renal vein, and SMA; suturing of posterior peritoneum; and incision closure. Results: Operative time was 131 minutes. Blood loss was 50 mL. No complication was observed. Hospital stay was 22 hours. Improvement of symptoms was obtained. Time to normal activities was 2 weeks. Esthetic aspect was satisfactory. Postoperative Doppler showed normal renal vein drainage. Conclusion: LESS extravascular renal vein stent is safe and feasible to treat nutcracker syndrome. The authors have nothing to disclose. Runtime of video: 8 mins 15 secs

ナットクラッカー症候群，腎盂尿管移行部狭窄及び多発腎結石に対し一期的外科治療を施行した1例

A 20 year-old man presented to emergency room with severe left-sided flank pain. Urinalysis showed hematuria and he was referred to the urology department. KUB, DIP and retrograde pyelography (RP) revealed multiple renal stones, left hydronephrosis (grade 2) and ureteropelvic junction obstruction (UPJO). Abdominal CT revealed shortened nutcracker distance and renal angiography showed left renal vein hypertension. From these findings, diagnosis of nutcracker syndrome was made. Transposition of the left renal vein, dismembered pyeloplasty and left pyelolithotomy were performed simultaneously. 2 months after the procedure, his symptom and hematuria disappeared. 3 months after the procedure, DIP revealed improvement of hydronephrosis (grade 1) and CT showed elongation of nutcracker distance. In 12 months follow-up, there was no recurrence of symptom and hydonephrosis. To the best our knowledge, there has been no report of UPJO associated with nutcracker syndrome and the simultaneous treatment for the both diseases.

Diagnosis and Surgical Treatment of Nutcracker Syndrome: A Single-Center Experience

To report our experience in the diagnosis and surgical treatment of the nutcracker syndrome, which is uncommon, with few larger series published. We retrospectively analyzed 23 patients with the nutcracker syndrome who presented to our institution from July 1998 to July 2007. A diagnosis of the nutcracker syndrome was suspected from the clinical examination, ultrasound, computed tomography, and magnetic resonance imaging findings. The diagnosis was confirmed by determination of the renocaval gradient using phlebography of the left renal vein (LRV). Because of recurrent gross hematuria and persistent orthostatic proteinuria, 7 patients (4 females and 3 males) underwent LRV transposition. Other patients with mild and tolerable symptoms were treated conservatively. The follow-up range was 14-122 months (mean 42.6). All 23 patients met the criteria for establishing the diagnosis of the nutcracker syndrome. Ultrasonography, computed tomography, and magnetic resonance imaging revealed entrapment of the LRV between the superior mesenteric artery and aorta. The renocaval pressure gradient was > or = 4 mm Hg (normal < 1 mm Hg) in all patients. The hematuria and proteinuria disappeared in the 7 patients who underwent LRV transposition, and only 1 patient continued to have pelvic pain. No complications occurred during surgery. The postoperative complications included paralytic ileus in 2 and retroperitoneal hematoma in 1 patient. No improvement or only partial improvement was observed in most patients receiving conservative treatment. The diagnosis of the nutcracker syndrome is determined from the clinical examination and radiographic findings. In patients who require surgical treatment, LRV transposition is an efficient surgical approach with an acceptable risk of complications. However, in some cases, pelvic pain may persist despite removal of the obstruction of the renal venous backflow.

Nutcracker Syndrome Diagnosed with 3-Dimensional Computed Tomography Angiography

We report a case of nutcracker syndrome diagnosed with 3-dimensional computed tomography angiography (3-D CTA). Nutcracker syndrome had been confirmed by conventional venography until recent years. Nowadays, with the development of imaging techniques, color Doppler sonogram and 3-D CTA are replacing venography for the diagnosis of nutcracker syndrome. The patient, a 20-year-old male, had abrupt gross hematuria and left abdominal pain 6 months previously and intermittent microscopic hematuria thereafter. Including renal biopsy, the results of conventional hematuria study showed no abnormalities. 3-D CTA showed left renal vein compression between the abdominal aorta and superior mesenteric artery and collateral veins. The angle and distance between the superior mesenteric artery and aorta at the level of the left renal vein were 35 o and 3.0 mm, respectively. We diagnosed nutcracker syndrome and later confirmed the diagnosis with venography. (Korean J Urol 2009;50:711-713)

Nutcracker Syndrome in Children

The purpose of this study was to evaluate the pathophysiologic characteristics of nutcracker syndrome (NS) and to assess the role of upright position imaging and superior mesenteric artery (SMA) angle measurement in the diagnosis. Doppler sonographic findings in 23 children with NS and in 26 healthy control subjects were compared. The mesenteric angle, peak velocity (PV), and anteroposterior diameter of the left renal vein (LRV) at the hilar and aortomesenteric portions were measured in both the supine and upright positions. The means +/- SD of the SMA angle, anteroposterior diameter, and PV ratio between the two portions were calculated, and cutoff levels for the diagnosis of NS were established. The diameter and PV ratios were significantly different between the patient and control groups in both the supine and upright positions (P < .001). Differences between the supine and upright positions were also significant for the diameter of the LRV at the aortomesenteric portion, diameter ratio, and SMA angle in both groups. Upright position imaging revealed comparatively narrower SMA angles and more pronounced entrapment findings in patients with NS. The SMA angle measurement had sensitivity and specificity of 69.6% and 61.5%, respectively, in the supine position and 87.0% and 76.9% in the upright position when the cutoff values were set to less than 41 degrees and 21 degrees , respectively. The upright position has significant effects on the LRV hemodynamics and angle of the SMA in both patients and healthy subjects. Superior mesenteric artery angle measurement may be a useful adjunct parameter in the diagnosis of NS.