Imaging findings and clinical features of abdominal vascular compression syndromes

Abdominal vascular compression syndromes: A pictorial review

Abdominal vascular compression syndromes (AVCS) refer to the entrapment of blood vessels between surfaces in a restricted space, a phenomenon that may cause clinical manifestations and can be identified using imaging methods. Although uncommon, their hemodynamic repercussions may lead to potential morbidity and should therefore be recognized by radiologists, who play a crucial role in diagnosing these conditions. Contrast-enhanced computed tomography (CECT) is the imaging modality of choice, primarily valued for its precision in identifying anatomical abnormalities, thereby facilitating appropriate management and reducing the risk of subsequent complications. Follow-up may range from conservative to invasive approaches, including surgical and endovascular procedures. This pictorial review focuses on the main imaging patterns of AVCS. Our objective is to enhance radiologists' ability to discern abdominal vascular anatomy, its interrelations with neighboring structures and its variants, and assist in the analysis of potential etiologies and pathophysiological mechanisms associated with these anomalies.

Controversies in treating nutcracker syndrome

Nutcracker syndrome (NCS) is a relatively uncommon vascular condition characterized by compression of the left renal vein (LRV), resulting in a variable spectrum of nonspecific symptoms, including hematuria, flank pain, varicocele, and pelvic congestion syndrome. NCS can be classified into anterior and posterior types regarding the origin of LRV compression: anterior NCS occurs when LRV is compressed between the aorta and superior mesenteric artery, whereas posterior NCS involves LRV compression between the aorta and the spine. Despite advancements in diagnostic modalities, including Doppler ultrasound, computed tomography, magnetic resonance imaging, and invasive techniques like phlebography, there is still no globally accepted diagnostic algorithm, leading to inconsistencies in diagnosis. Moreover, due to the lack of standardized treatment guidelines, the optimal management of anterior NCS remains a topic of debate. While conservative management is usually recommended in the pediatric population, invasive treatments-including surgical options like LRV transposition and renal autotransplantation, as well as interventional radiology procedures like stenting, present challenges such as stent migration, restenosis, and long-term material durability. Nevertheless, the emergence of 3D-printed stents offers potential improvements in patient-specific treatment, particularly in the pediatric population, yet their clinical efficacy and safety remain under investigation. This brief communication addresses the current discussions regarding anterior NCS management, emphasizing the need for standardized diagnostic algorithms, a multidisciplinary approach, and continued technological advancements to refine treatment possibilities and strategies. Further research is critical to resolve these controversies and establish a consensus on best practices.

Under pressure: a head-to-toe review of vascular compression syndromes

Vascular compression syndromes are a group of conditions resulting from mechanical compression of blood vessels by adjacent structures leading to compromised blood flow and various associated symptoms. They frequently affect young, otherwise healthy individuals and are often underdiagnosed due to their rarity and vague clinical manifestations. Achieving an accurate diagnosis depends on the integration of clinical presentation and imaging findings. Imaging modalities including color doppler ultrasound, computed tomography angiography, magnetic resonance angiography, and catheter-directed digital subtraction angiography are essential for diagnosis and management. Dynamic imaging is crucial in eliciting findings due to the positional nature of many of these syndromes. In this paper, we will present a "head-to-toe" overview of vascular compression syndromes including Vascular Eagle Syndrome, Vascular Thoracic Outlet Syndrome, Quadrilateral Space Syndrome, Hypothenar Hammer Syndrome, Median Arcuate Ligament Syndrome, Renal Artery Entrapment Syndrome, Left Renal Vein Compression/Nutcracker Syndrome, May-Thurner Syndrome, Adductor Canal Syndrome, and Popliteal Artery Entrapment Syndrome. Treatment is variable but typically involves a combination of conservative and surgical management. Surgical approaches focus on decompression of affected neurovascular structures. Endovascular treatment alone is rarely recommended. We aim to equip general radiologists with the knowledge needed to accurately diagnose patients with vascular compression syndromes, allowing for timely treatment.

A radio-anatomical study of median arcuate ligament syndrome: unveiling the morphology and morphometry of median arcuate ligament, celiac trunk, and superior mesenteric artery

PURPOSE

In the context of medical literature, a significant lacuna exists in understanding median arcuate ligament syndrome (MALS). While clinical aspects are well documented, literature lacks a robust exploration of the anatomical relationship between the celiac trunk and the median arcuate ligament (MAL).

METHODS

Morphometric parameters, including the vertebral level of MAL origin, MAL thickness, celiac trunk (CeT) origin level, diameter, and distances between CeT/Superior Mesenteric Artery (SMA) and the MAL center were observed on 250 CT angiograms. Cadavers (n = 11) were dissected to examine the same parameters and histo-morphological examination of MAL tissue was done.

RESULTS

Radiological findings established average MAL thickness of 7.79 ± 2.58 mm. The celiac trunk typically originated at T12. The average distance between the celiac trunk and the MAL center was 1.32 ± 2.04 mm. The angle of the celiac trunk to the abdominal aorta was primarily obtuse. The average celiac trunk diameter was 5.53 ± 1.33 mm. Histological examinations revealed a diverse MAL composition, indicating variable mechanical properties.

CONCLUSION

This study provides comprehensive morphometric data on the anatomical relationship between the MAL and the celiac trunk. In contrast to available literature which says the average MAL thickness of > 4 mm is an indicator of increased thickness, we observed much higher average thickness in the studied population. The findings contribute to a better understanding of normal anatomical variations which can serve as reference values for accurate radiological diagnosis of MALS. The histological examination revealed the heterogeneous nature of the MAL tissue composition, suggesting variable mechanical properties and functions in different regions.

Correlation of Imaging and Hemodynamic Findings with Clinical Outcomes for Diagnosis of Left Renal Vein Compression Syndrome

PURPOSE

Left renal vein compression syndrome (LRVCS) remains a challenging diagnosis. This study aimed to correlate imaging and hemodynamic findings with clinical outcomes for patients with LRVCS.

MATERIALS AND METHODS

A retrospective review of 66 renal venography procedures with or without intravascular ultrasound (IVUS) was performed from 2017 to 2023 at a single institution. Patients with prior LRVCS treatment or other indications were excluded (n = 11). Primary outcome measure was correlation of catheter-based endovascular (CBE) findings with clinical outcomes (n = 55). Secondary outcome measures included correlation of CBE findings and LRV (i.e., beak) angle > 32°, beak sign, aortomesenteric angle (AMA < 41°), and hilar-to-aortomesenteric ratio (HTAMR ≥ 4.9) on cross sectional imaging. Descriptive statistics, chi-square testing, and ROC analyses were used.

RESULTS

Of the 55 patients, 52 (94.5%) were females (median age 31, range 14-72) and 56.4% (n = 31) had a diagnosis of LRVCS on CBE evaluation. A renocaval pressure gradient of ≥ 3 mmHg, presence of collaterals, and > 50% area stenosis on IVUS were significantly associated with CBE diagnosis of LRVCS (p < 0.001). Surgical treatment (renal autotransplantation or LRV transposition) was recommended to all patients with CBE diagnosis of LRVCS (n = 31). 81.2% (18/22) of patients who underwent surgery reported symptom resolution or improvement. When the cross sectional imaging measurements were compared with CBE evaluation, AMA was the most sensitive (100%), HTAMR and beak sign were highly specific (93.3%), and beak angle was the most predictive (77.4% sensitivity; 86.7% specificity).

CONCLUSION

CBE diagnosis of LRVCS was highly predictive of surgical candidacy and post-surgical symptom resolution. The presence of collaterals, > 50% area stenosis on IVUS, or a renocaval pressure gradient ≥ 3 mmHg had a significant association with a CBE diagnosis of LRVCS.

A unique posterior nutcracker syndrome combined with Wilkie syndrome: A singular case

Left renal vein variants are not commonly observed in the general population. Usually, the renal vein runs in front of the aorta before entering the inferior vena cava, while the most common variants include the presence of a circumaortic or retroaortic renal vein. However, when present, left venal rein variants are important to recognize due to their potential clinical and surgical relevance. In this regard, CE-CT is an instrument with high sensitivity and specificity in detecting vascular anomalies and can certainly help diagnose. In this article, we present a unique case of a left venal rein compressed between the left iliac artery and vertebral bodies associated with the presence of a superior mesenteric artery Syndrome, another rare entity that occurs when the duodenum is compressed between the aorta and the superior mesenteric artery.

Doppler Ultrasound of the Renal Vasculature

Ultrasound is the first-line imaging modality used in patients with suspected renovascular disease. Common indications include renovascular hypertension and unexplained renal dysfunction. We review the ultrasound imaging findings of various pathologies involving the renal vessels, including the renal arteries (atherosclerotic stenosis, fibromuscular dysplasia, dissection, arteriovenous fistula, and aneurysm) and veins (tumor and bland thrombus as well as vascular compression syndromes). The current role of renal artery stent placement for atherosclerotic stenosis is also discussed.

Exploring celiac trunk parameters in median arcuate ligament syndrome: A CT study

PURPOSE

To assess anatomical variations in the celiac trunk (Ct) in patients with Median Arcuate Ligament Syndrome (MALS) using computed tomography (CT). The primary objectives were to investigate the celiac trunk angle (CtA), origin level, length (CtL), and their relationships with the superior mesenteric artery (SMA) in MALS patients. Additionally, the study intended to evaluate gender differences in these parameters and explore correlations between variables.

METHODS

Retrospectively, reports of abdominal CT scans taken between January 2018, and Sepmtember 2021, in the hospital image archive were screened vey two observers independently for MALS diagnosis. Parameters such as CtA, CtL, Ct-SMA distance, SMA angle (SMAA), and median arcuate ligament thickness (MALT) were measured. Statistical analyses were conducted using SPSS software.

RESULTS

Among the 81 patients (25 females, 56 males), significant differences were observed in MALT between genders (p = 0.001). CtA showed a negative correlation with CtL and Ct-SMA (p < 0.001), and a positive correlation was found between CtL and Ct-SMA (p = 0.002). CtL was measured as 25 mm for the all group. Origin levels of Ct and SMA were evaluated in comparison to vertebral levels. Ct-SMA distance was relatively shorter (9.19 mm) compared to the literature. SMAA findings were consistent with normal population values.

CONCLUSION

This study provided valuable insights into the anatomical parameters of the Ct ans SMA in MALS patients. Despite some differences compared to normal population parameters, no evidence supported the hypothesis of a superiorly placed Ct contributing to MALS.

Evaluating aortomesenteric parameters in a tertiary center of Nepal for superior mesenteric artery syndrome diagnosis and risk factors: cross-sectional study

Background and objectives

This study examines aortomesenteric angle (AMA) and distance (AMD), which are critical in superior mesenteric artery (SMA) syndrome. Addressing the scarcity of SMA cases, the research explores potential links with lower BMI and aims to establish normative data for diagnostic and predictive purposes, using contrast-enhanced computed tomography (CT) scans across various BMI and sex categories.

Methodology

A retrospective quantitative cross-sectional study was conducted on 189 patients undergoing abdominal contrast-enhanced CT scans between December 2019 and December 2020. Ethical clearance was obtained, and participants provided informed consent. Exclusion criteria targeted specific medical histories. Patient demographics, BMI categories, and imaging data were recorded. Helical 128-slice CT scans were employed, with sagittal-oblique multiplanar reconstructions for parameter assessments. Statistical analysis utilized SPSS 26.0, including Pearson correlation coefficients and mean calculations.

Results

The study reveals a mean AMA of 54.07°±8.53° and a mean distance of 16.25±3.44 mm. Elevated BMI is found to positively correlate with AMA and distance, indicating that higher BMI values may augment these parameters, with an additional positive correlation observed between AMA and distance. No significant correlations are found with patient age or sex.

Conclusion

The study concludes that decreased BMI may pose a potential risk for SMA syndrome, as evidenced by the observed correlations with aortomesenteric parameters. Understanding these normal values in the Nepalese population is critical for accurate diagnoses and predictions using CT scans. The research highlights the impact of demographic factors on these parameters and emphasizes their significance in clinical assessments related to SMA syndrome.

Superior Mesenteric Artery Syndrome: A Misdiagnosed Disorder

The superior mesenteric artery syndrome also known as Wilkie's syndrome or Benign duodenal stasis, is a condition that occurs when the third duodenum is compressed between the superior mesenteric artery anteriorly and the abdominal aorta posteriorly following the disappearance of the perivascular fatty tissue. It can emulate the symptoms of an upper abdominal obstruction. This case involves a 9-year-old female patient experiencing food vomiting that did not improve with medication. Radiological work-up, which included an abdominal X-ray and a CT angiography, led to the diagnosis of extrinsic and incomplete obstruction of the third duodenum by the aorto-mesenteric clamp. Unfortunately, this diagnosis is rarely made. The purpose of this article is to provide a review of the etiology, clinical presentation, and imaging findings of this syndrome.

Ultrasound characteristics of abdominal vascular compression syndromes

Abdominal vascular compression syndrome (AVCS) is caused by the compression of abdominal blood vessels by adjacent structures or the compression of abdominal organs by neighboring blood vessels. Such compressions can result in a variety of clinical symptoms. They are not commonly seen in ultrasound practices, and their presence may have been underrecognized and underdiagnosed. This article reviews the clinical features, ultrasound characteristics, and diagnostic criteria of four types of AVCS, namely, celiac artery compression syndrome, renal vein compression syndrome, iliac vein compression syndrome, and superior mesenteric artery syndrome to increase awareness of these conditions among ultrasound practitioners. The ultrasound criteria for AVCS are primarily based on studies with small sample sizes, and therefore, it is important to exercise caution if these criteria are used.

Understanding the diagnosis of superior mesenteric artery syndrome: analysis of the location of duodenal impression on upper gastrointestinal studies

BACKGROUND

Upper gastrointestinal (GI) contrast studies are frequently requested to aid superior mesenteric artery syndrome diagnosis, a rare entity. Compression of the third duodenal part is expected to be mid-to-left of the midline where the superior mesenteric artery arises from the aorta; however, a duodenal impression to the right of the midline due to normal anatomic impression by the inferior vena cava (IVC) is often encountered and frequently misdiagnosed.

OBJECTIVE

The purpose of this study was to determine the frequencies of (1) normal right-of-midline duodenal impressions and (2) mid-to-left of midline compressions in upper GI studies in a tertiary pediatric referral center.

MATERIALS AND METHODS

All upper GI studies performed at our institution over 2 years were retrospectively evaluated to determine whether the duodenum had vertical duodenal impression to the right of the vertebral midline, mid-to-left of the vertebral midline, or no identifiable duodenal impression at all.

RESULTS

In total, 538 upper GI studies were included in this analysis. A total of 275 male and 247 female patients between 0 and 17 years of age (median: 6 years, range: 1 month-17 years) were included. Of 538 total upper GI studies, there were 240 studies (44.6%) with a right-of-midline impression. There were only 10 studies (1.9%) with a mid-to-left of midline compression, and 9/10 also showed a concurrent right-sided impression sign.

CONCLUSION

Right-of-midline duodenal impression is a normal anatomic finding caused by the IVC and should not be confused with superior mesenteric artery syndrome. In the presence of an appropriate clinical context, proximal duodenal dilation, "to-and-fro" motion of contrast, and duodenal impression at mid-to-left of midline, a diagnosis of superior mesenteric artery syndrome should be considered.

Body and Extremity MR Venography: Technique, Clinical Applications, and Advances

Magnetic resonance venography (MRV) represents a distinct imaging approach that may be used to evaluate a wide spectrum of venous pathology. Despite duplex ultrasound and computed tomography venography representing the dominant imaging modalities in investigating suspected venous disease, MRV is increasingly used due to its lack of ionizing radiation, unique ability to be performed without administration of intravenous contrast, and recent technical improvements resulting in improved sensitivity, image quality, and faster acquisition times. In this review, the authors discuss commonly used body and extremity MRV techniques, different clinical applications, and future directions.

An interesting presentation of a rare association of the Wilkie and Nutcracker syndromes

Superior mesenteric artery syndrome also known as Wilkie's syndrome (WS) and Nutcracker syndrome (NCS) are 2 rare vascular syndromes characterized by the reduction of the aortomesenteric space. In the WS the reduction of the aortomesenteric angle leads to compression of the third portion of the duodenum. In the NCS the reduced aortomesenteric space usually causes a left renal vein (LVR) entrapment and the clinical presentation is a left flank pain, micro/macrohematuria and proteinuria. Arterial hypertension can be an unusual manifestation of the NCS. Herein, we describe the case of a 37-year-old woman with a history of breast cancer and abdominal subocclusion, with a recent onset of arterial hypertension whose enhanced computed tomography (CT) showed a reduced angle between the abdominal aorta and superior mesenteric artery with the CT findings of both the WS and NCS.

Superior Mesenteric Artery Thrombosis in a Patient With Median Arcuate Ligament Syndrome

Median arcuate ligament syndrome (MALS) is a rare and controversial vascular compression syndrome. In this condition, the median arcuate ligament compresses the celiac artery, resulting in symptoms such as postprandial abdominal pain, vomiting, and weight loss. Its diagnosis is based on clinical findings in conjunction with supporting radiological features such as elevated flow velocities on Doppler ultrasound and focal indentation of the proximal celiac artery with the typical 'hooked' or 'J'-shaped appearance on conventional angiography or computed tomography angiography (CTA). Herein is the case of a 44-year-old female who presented with early satiety, postprandial abdominal pain, vomiting, and weight loss. A computed tomography mesenteric angiogram (CTMA) showed thickening of the median arcuate ligament with a hooked appearance of the celiac artery and thrombosis of the mid to distal superior mesenteric artery with associated ischemia of a short segment of the jejunum. Subsequent Doppler ultrasound demonstrated elevated peak systolic velocities within the celiac artery over the compressed segment, which varied with respiration (end-inspiration: 234.3 cm/s and end-expiration: 373.5 cm/s).

Novel Use of Time-Resolved Magnetic Resonance Angiography to Evaluate Retrograde Lumbar Vein Flow and Epidural Venous Plexus Enhancement in Chronic Headache Patients With and Without Nutcracker Physiology

OBJECTIVE

Compression of the left renal vein by the superior mesenteric artery, known as nutcracker phenomenon (NCP), can cause retrograde flow and congestion in communicating venous systems. It has recently been speculated that NCP can result in retrograde flow and congestion of the lumbar veins and epidural venous plexus (EVP), thereby affecting the central nervous system. This study describes the novel use of time-resolved magnetic resonance angiography (trMRA) to evaluate for retrograde left second lumbar vein (L2LV) flow and early EVP enhancement in patients with chronic daily headache (CDH) with and without NCP.

METHODS

A retrospective analysis was performed of 31 patients with CDH (27 females and 4 males; median age, 38 years [range, 18-63 years]) who underwent trMRA centered over the L2LV to evaluate the direction of blood flow and presence of early EVP enhancement from May 2020 to March 2022. Descriptive statistics were performed, and anatomic associations were analyzed in patients with and without retrograde L2LV flow and early EVP enhancement. The accuracy of magnetic resonance imaging findings in detecting these flow patterns was also assessed.

RESULTS

Patients with NCP who demonstrated narrowing of the left renal vein, a positive beak sign ( P = 0.052), decreased aortomesenteric distance ( P = 0.038), and decreased SMA angle demonstrated increased rates of retrograde L2LV flow and early EVP enhancement. A positive beak sign was 83% specific, and an aortomesenteric distance of ≤6.5 mm was 61% sensitive and 83% specific for identifying retrograde L2LV flow with early regional EVP enhancement in patients with CDH.

CONCLUSIONS

Retrograde L2LV flow with early EVP enhancement in CDH patients can be effectively evaluated using trMRA and was seen with greater propensity in those patients with NCP.

The Clinical Problem of Pelvic Venous Disorders

Pelvic venous disorders are inter-related pathologic conditions caused by reflux and obstruction in the pelvic veins. It can present a spectrum of clinical features based on the route of transmission of venous hypertension to either distal or caudal venous reservoirs. Imaging can help to visualize pelvic vascular and visceral structures to rule out other gynecologic, gastrointestinal, and urologic diseases. Endovascular treatment, owing to its low invasive nature and high success rate, has become the mainstay in the management of pelvic venous disorders. This article reviews the pathophysiology, clinical presentations, and diagnostic and therapeutic approaches to pelvic venous disorders.

Normal values of angle and distance between the superior mesenteric artery and aorta in Iraqi population: A single centre study

INTRODUCTION

The diagnosis of the superior mesenteric syndrome depends on measuring the distance and angle between the superior mesenteric artery (SMA) and aorta on CT scan in the presence of duodenal compression. Studies examining the normal range of these measurements are scarce and none of them was conducted on the Iraqi population. The aim of this study was to assess the values of aorto-SMA angle (AMA) and aorto-SMA distance (AMD) in asymptomatic patients to define the normal range in the Iraqi population and to compare it with the normal published range and different demographical values and body mass index (BMI).

METHODS

A total of 333 patients referred to arterial phase CT examinations for reasons unrelated to gastrointestinal tract were recruited. On axial and reformatted sagittal-oblique images, the angle and the distance between SMA and aorta were measured at the location where the duodenum crosses.

RESULTS

Both AMA and AMD had a wider range 10-147° and 4-44 mm, respectively, compared to the literature reported range. There was a significant reduction in AMA and AMD values in underweight participants (AMA, P < 0.001; and AMD, P = 0.014) and in female patients (AMA and AMD, P < 0.0001) and those who were younger than 20 (AMA, P = 0.014; and AMD, P = 0.001). A moderate correlation (r = 0.507, P < 0.0001) was found between AMA and AMD values. The correlation of BMI with AMD values was moderate (r = 0.46), and with AMA was weak (r = 0.23) (P < 0.0001).

CONCLUSION

Very low values of AMA and AMD can occur in normal asymptomatic patients without compressing the duodenum, which warrants further follow-up studies. Evaluating normal values of AMA and AMD in the Iraqi population can help in providing a reference for CT-based diagnosis of SMA syndrome.

Fluoroscopic Evaluation of Duodenal Diseases

The duodenum can be affected by a variety of abnormalities because of its development during embryogenesis and its dual intra- and retroperitoneal location. If small bowel embryogenesis is disturbed, congenital errors occur. Although some congenital variants may be asymptomatic and inconsequential to the patient, other anomalies can result in life-threatening emergencies such as malrotation, leading to midgut volvulus. Many infectious processes affect the duodenum, including duodenal ulcers and opportunistic infection in patients with HIV/AIDS or Crohn disease. Small bowel malignancies are uncommon but important to recognize, because the duodenum can be involved in polyposis syndromes or the development of primary adenocarcinoma, neuroendocrine tumors, lymphoma, and metastasis. Although endoscopy is currently the most used diagnostic method to assess the lumen of the upper gastrointestinal tract, fluoroscopy is a valuable adjunct technique and the study of choice for many diseases, specifically those for which anatomic and functional information is required. Fluoroscopy is also commonly used postoperatively to assess for complications such as obstruction and extraluminal leaks. Compared with endoscopy, fluoroscopy is an inexpensive and noninvasive technique that provides salient anatomic information and allows delineation of the duodenal mucosa and assessment of real-time duodenal motility. The authors examine the broad spectrum of conditions that can involve the duodenum, including congenital, infectious, inflammatory, and neoplastic abnormalities, and review their typical appearances at fluoroscopy. Online supplemental material is available for this article. ^©RSNA, 2022.

Celiac Artery Compression Syndrome: A Rare Cause of Abdominal Angina

Abdominal angina refers to an abdominal pain that develops shortly after food intake and gradually resolves after a few hours. It is related to insufficient mesenteric blood flow to meet the intestinal demand. In the majority of cases, this syndrome is caused by atherosclerotic narrowing of the mesenteric vessels. We report the case of a 61-year-old man, with a longstanding history of hypertension, diabetes mellitus, and dyslipidemia, who presented to the emergency department with acute abdominal pain that was aggravated by food intake. The patient reported similar but milder episodes of this pain for the last three years that led him to lose significant weight because of fear of eating. Despite this classic history of abdominal angina, his condition was misdiagnosed as indigestion, and was offered symptomatic treatment only. The basic laboratory findings were within the normal limits. The patient underwent a contrast-enhanced abdominal computed tomography scan in the arterial phase which demonstrated focal proximal stenosis of the celiac trunk due to thickened median arcuate ligament. Subsequently, the median arcuate ligament was resected laparoscopically to decompress the celiac artery. The surgical operation resulted in the complete resolution of the abdominal pain. Celiac artery compression syndrome is a rare etiology of abdominal angina. Computed tomography angiography is the imaging study of choice to make the diagnosis accurately. Laparoscopic resection of the median arcuate ligament is a safe and successful approach in the management.

Left double polar renal arteries, left triplicate (preaortic, accessory and retroaortic) renal veins associated with extrinsic pelviureteric junction obstruction and posterior nutcracker phenomenon

The renal vasculature and its various congenital anomalies have been studied and documented widely in the literature. However, the concomitant occurrence of renovascular morphological anomalies with vascular compression phenomena in a single patient is a rarity. This is a case of a patient with double left renal arteries, preaortic, accessory and retroaortic left renal veins. There was also associated with vascular compression phenomena in the form of posterior nutcracker phenomenon and pelviureteric junction obstruction (PUJ) due to the double-crossing inferior left polar renal artery and retroaortic vein.

Sonographic Evaluation of Pelvic Venous Disorders

ABSTRACT

Pelvic venous disorders are a group of interrelated conditions characterized by venous incompetence. These conditions often manifest with nonspecific symptoms that overlap with many gynecological, gastrointestinal, and urologic diseases. Clinical diagnosis can be difficult, and imaging can play a vital role in differentiating etiology. Sonographic evaluation is often the first step in evaluating these symptoms. Special attention to possible underlying pelvic venous disorders can reveal characteristic findings, support diagnosis, and guide treatment. Here we review pelvic congestion syndrome, nutcracker syndrome, May-Thurner syndrome, and other venous disorders, with a specific focus on sonographic findings and considerations.

Endovascular management of nutcracker syndrome in an adolescent patient population

BACKGROUND

Nutcracker syndrome is defined as left renal vein compression with concomitant clinical symptoms that include flank pain and hematuria. Historically, pediatric and adolescent patients with mild symptoms of nutcracker syndrome were simply observed while those with more severe symptoms underwent left renal vein transposition. Endovascular stenting of the left renal vein is a potentially efficacious and less invasive alternative for managing nutcracker syndrome in adolescents.

OBJECTIVE

The purpose of this study was to investigate the technical feasibility, efficacy and safety of left renal vein stenting in adolescents with nutcracker syndrome.

MATERIALS AND METHODS

We conducted a retrospective review of electronic medical records and imaging archives to identify adolescents undergoing endovascular stenting for nutcracker syndrome. We reviewed patient demographics including age, gender, presenting symptoms and diagnostic imaging findings. We compared pre- and post-stent deployment intravascular ultrasound (IVUS) and venography and evaluated patient symptoms in clinic up to 6 months following stent placement.

RESULTS

Ten patients (average age 16 years, range 12-20 years) underwent 13 procedures. Initial symptoms included pain (n=10) and gross hematuria (n=5). Diagnostic imaging studies included CT abdomen pelvis (n=8), retroperitoneal US (n=6), MRI abdomen/pelvis (n=4), scrotal US (n=2), pelvic US (n=1) and renal Doppler US (n=2). Venography and IVUS demonstrated venous collaterals, proximal blanching at the left-renal-vein-IVC junction, pre-stenotic dilation and intraluminal compression. Most patients (n=9) experienced symptomatic resolution; however, three patients required reintervention to achieve asymptomatic status. No periprocedural complications occurred.

CONCLUSION

In this carefully selected adolescent cohort, left renal vein stenting for nutcracker syndrome was often technically feasible, safe and effective in symptom management.

Nonnegligible causes of symptoms of acute lower extremities--3 cases of May-Thurner syndrome with deep vein thrombosis

Background

May-Thurner syndrome is a kind of disease caused by the compression of the left common iliac vein. It is one of the causes of incomplete venous valves and superficial varicose veins in lower limbs, and is also a potential factor of acute deep vein thrombosis (DVT).

Method

Here 3 cases are diagnosed as May-Thurner syndrome at different ages.

Case presentations

1. A 35-year-old female patient was hospitalized with swelling of the left lower limb for 1 week. Computed tomography (CT) showed compression of the left common iliac vein with thrombosis. May-Thurner syndrome was diagnosed and catheter-directed thrombolysis was performed. 2. A 37-year-old male patient came to our hospital due to sudden swelling of the right lower extremity and pain for 3 days. Computed tomography showed compression of the left common iliac vein and deep venous thrombosis (DVT) of the right iliac vein. May-Thurner syndrome was diagnosed. The patient was performed with inferior vena cava (IVC) filter implantation, catheter-directed thrombolysis and balloon angioplasty for right iliac vein. And the patient recovered well; 3. A 55-year-old female patient came to our hospital with swelling and discomfort in the left lower extremity for 3 days. Computed tomography showed stenosis of the left common iliac vein with deep vein thrombosis. May-Thurner syndrome was diagnosed, balloon dilation and stent implantation were performed. During 3 years of follow-up, there was no swelling or new thrombosis in her lower limbs.

Conclusion

When encountering unexplained deep vein thrombosis, iliac vein compression syndrome should be considered and treated in time to prevent the recurrence of thrombosis. Catheter-directed thrombolysis can relieve symptoms and stenting placement is the optimal way to relieve stenosis, supplemented by long-term anticoagulation therapy and graduated compression stockings.

Imaging of retroperitoneal haemorrhage revealing median arcuate ligament syndrome

Coeliac artery compression stenosis caused by the median arcuate ligament can lead to aneurysm formation in the pancreatico-duodenal arteries that can eventually result in a spontaneous rupture leading to retroperitoneal haemorrhage. In this case series, we describe the cases of three patients, all presenting with sudden epigastric pain, diagnosed as spontaneous haematoma, complicating a median arcuate ligament syndrome.

Role of imaging in visceral vascular emergencies

Differential diagnosis in non-traumatic acute abdomen is broad and unrelated diseases may simulate each other from a clinical perspective. Despite the fact that they are not as common, acute abdominal pain due to diseases related to visceral vessels may be life-threating if not detected and treated promptly. Thrombosis, dissection, and aneurysm in the abdominal visceral arteries or thrombosis in visceral veins may cause acute abdominal pain. Imaging with appropriate protocoling plays a fundamental role in both early diagnosis and determination of the treatment approach in these cases where early treatment can be life-saving. Computed tomography (CT) appears to be the most effective modality for the diagnosis as it provides high detail images in a very short time. Patient cooperation is also a less concern as compared to magnetic resonance imaging (MRI). As the imaging findings may sometimes be really subtle, diagnosis may be difficult especially to inexperienced imagers. Correct protocoling is also very critical to detect arterial abnormalities as visceral arterial abnormalities may not be detectable in portal phase only abdominal CT scans. In this article, we aimed to increase awareness among imaging specialists to these not very common causes of acute abdomen.

Laparoscopic management of celiac artery compression syndrome: A case report

INTRODUCTION

Celiac artery compression syndrome is a rare disorder found mainly in young females. It many a times goes undiagnosed as the symptoms are non-specific and varied.

PRESENTATION OF THE CASE

We present a case of celiac artery compression syndrome in a young female where laparoscopic median arcuate ligament release with celiac ganglionectomy was effective in relieving the symptoms.

DISCUSSION

Commonly they may present with abdominal pain, vomiting and diarrhea but there is absence of significant clinical signs. High level of suspicion and the right imaging techniques like the lateral aortogram, helps us to clinch the diagnosis.

CONCLUSION

Laparoscopic release of celiac artery compression is a safe and effective method to treat this uncommon disease.

Predictors of Superior Mesenteric Artery Syndrome: Evidence from a Case-Control Study

Introduction Superior mesenteric artery (SMA) or Wilkie's syndrome is a rare condition arising due to compression of the third part of the duodenum between the abdominal aorta and the superior mesenteric artery. It is important to explore factors which help in suspicion and early diagnosis of the condition. The aim of this study was to find out if measurements of aortomesenteric angle and distance can predict the occurrence of SMA syndrome. Another objective was to find out if the BMI was correlated with the aortomesenteric angle and distance of the patients. Methods A retrospective hospital-based case-control study was conducted in Qimat Rai Gupta Central hospital, Haryana, India from 2018-2020. Out of total 2100 records of acute and chronic abdominal pain patients, only seven cases of Wilkie's syndrome were confirmed via Contrast-Enhanced Computed Tomography (CECT). Information on age, gender, BMI, duration of symptoms, clinical presentation, aortomesenteric angle, and distance was compared among three groups: Group I-SMA syndrome patients (N=7), Group II- acute abdominal pain patients (N=14) and Group III- chronic abdominal pain patients (N=14). Results The hospital prevalence of Wilkie's was found to be 0.3%. The median age of patients in Group I corresponded to 26 years as opposed to Group II (31.5years) and Group III (30.5 years). There was a statistically significant reduction in the aortomesenteric angle and distance of Group I patients (22º, 6mm) as compared to both Group II (52.5º, 11mm) and Group III patients (52º, 11mm). A moderate correlation of BMI was found with aortomesenteric angle (r=0.479) and distance (r=0.357). Conclusions There was a significant reduction in the aortomesenteric angle and distance of the SMA patients as compared to both patients having acute and chronic abdominal pain. The BMI of patients was positively correlated to aortomesenteric angle and distance to the moderate level. Thus BMI along with aortomesenteric angle and distance can predict the presence of SMA syndrome.

In Well-Selected Patients With a Femoral Deep Vein Thrombosis Central Venous Imaging May Identify Additional Iliocaval Disease

OBJECTIVE

Patients who present acutely with a femoral deep vein thrombosis (DVT) diagnosed by ultrasound are often treated with anticoagulation and instructed to follow-up electively. This study sought to assess whether obtaining axial imaging of the central venous system results in the identification of additional iliocaval pathology warranting treatment.

METHODS

This study was a retrospective review of a prospectively maintained registry from November 2014 through April 2017 with follow-up through March 2020. Consecutive patients with a diagnosis of femoral DVT diagnosed by ultrasound were evaluated; those who underwent axial imaging of the iliocaval system (Group A) were compared to those who did not undergo imaging of the central veins (Group B). The primary outcome was the performance of any percutaneous central venous intervention. Secondary outcomes included the extent of DVT identified on duplex and after axial imaging, follow-up duplex patency and persistence of severe symptoms.

RESULTS

Eighty patients presented with an ultrasound diagnosis of a femoral vein DVT. Mean follow-up was 551 ± 502 days. Group A comprised 24 patients (30%) and Group B comprised 56 patients (70%). Baseline demographics did not differ significantly between the 2 groups. After duplex imaging, Group A exhibited an increased prevalence of DVT in the common femoral vein. After central imaging, Group A exhibited an increased prevalence of DVT in the iliocaval veins. The number of patients who underwent invasive treatment differed significantly between the 2 groups, Group A 16/24 (67%) vs. Group B 9/56 (16%), P < 0.0001. The number of patients that demonstrated duplex patency and had persistent symptoms on follow-up did not differ significantly.

CONCLUSIONS

Patients with an ultrasound diagnosis of femoral DVT may have additional iliocaval pathology warranting intervention. Well-selected imaging of the central veins may reveal a more complete picture, potentially altering management.

Doppler US and CT Diagnosis of Nutcracker Syndrome

Nutcracker syndrome (NCS) is a syndrome caused by compression of the left renal vein (LRV), between the abdominal aorta and the superior mesenteric artery, resulting in hypertension of the LRV and hematuria. Doppler ultrasonography (US) has been commonly used for the diagnosis of NCS. However, several technical issues, such as Doppler angle and sample volume, need to be considered to obtain satisfactory results. In addition, morphologic changes of the LRV and a jetting phenomenon across the aortomesenteric portion of the LRV on contrast-enhanced computed tomography (CECT) are diagnostic clues of NCS. With proper Doppler US and CECT, NCS can be diagnosed noninvasively.

Image in transplantation surgery: median arcuate ligament in liver transplantation

Low inserted median arcuate ligament (MAL) may cause extrinsic coeliac trunk compression and MAL syndrome (association of post-prandial epigastric pain, weight loss and nausea or vomiting). In liver transplantation (LT), liver graft arterial supply depends on the recipient's hepatic artery, as the gastro-duodenal artery has generally been ligated. A decreased graft arterial flow caused by coeliac trunk stenosis might induce hepatic artery thrombosis leading to graft loss. In this short report, the authors describe LT procedure during which recipient's hepatic artery pressure was dramatically decreased after ligature of the gastro-duodenal artery. Dissection and division of the MAL allowed to restore an excellent blood flow through the hepatic artery. This report reminds how important it is to be able to recognize and how to manage a stenosing MAL in LT.

Imaging diagnosis and staging of pancreatic ductal adenocarcinoma: a comprehensive review

Pancreatic ductal adenocarcinoma (PDAC) has continued to have a poor prognosis for the last few decades in spite of recent advances in different imaging modalities mainly due to difficulty in early diagnosis and aggressive biological behavior. Early PDAC can be missed on CT due to similar attenuation relative to the normal pancreas, small size, or hidden location in the uncinate process. Tumor resectability and its contingency on the vascular invasion most commonly assessed with multi-phasic thin-slice CT is a continuously changing concept, particularly in the era of frequent neoadjuvant therapy. Coexistent celiac artery stenosis may affect the surgical plan in patients undergoing pancreaticoduodenectomy. In this review, we discuss the challenges related to the imaging of PDAC. These include radiological and clinical subtleties of the tumor, evolving imaging criteria for tumor resectability, preoperative diagnosis of accompanying celiac artery stenosis, and post-neoadjuvant therapy imaging. For each category, the key imaging features and potential pitfalls on cross-sectional imaging will be discussed. Also, we will describe the imaging discriminators of potential mimickers of PDAC.

Venous Thrombosis and Hypercoagulability in the Abdomen and Pelvis: Causes and Imaging Findings

Venous thromboembolism (VTE), which includes deep venous thrombosis and pulmonary embolism, is a significant cause of morbidity and mortality. In recent decades, US, CT, and MRI have surpassed catheter-based angiography as the imaging examinations of choice for evaluation of vascular structures and identification of thrombus owing to their ready availability, noninvasive nature, and, in the cases of US and MRI, lack of exposure to ionizing radiation. As a result, VTE and associated complications are commonly identified in day-to-day radiologic practice across a variety of clinical settings. A wide range of hereditary and acquired conditions can increase the risk for development of venous thrombosis, and many patients with these conditions may undergo imaging for unrelated reasons, leading to the incidental detection of VTE or one of the associated complications. Although the development of VTE may be an isolated occurrence, the imaging findings, in conjunction with the clinical history and vascular risk factors, may indicate a predisposing condition or underlying diagnosis. Furthermore, awareness of the many clinical conditions that result in an increased risk of venous thrombosis may aid in detection of thrombus and any concomitant complications. For these reasons, it is important that practicing radiologists be familiar with the multimodality imaging findings of thrombosis, understand the spectrum of diseases that contribute to the development of thrombosis, and recognize the potential complications of hypercoagulable states and venous thrombosis. Online DICOM image stacks and supplemental material are available for this article. ^©RSNA, 2020.

CT imaging findings of abdominopelvic vascular compression syndromes: what the radiologist needs to know

Abdominopelvic vascular compression syndromes include a variety of uncommon conditions characterized by either extrinsic compression of blood vessels by adjacent anatomical structures (i.e., median arcuate ligament syndrome, nutcracker syndrome, May-Thurner syndrome) or compression of hollow viscera by adjacent vessels (i.e., superior mesenteric artery syndrome, ureteropelvic junction obstruction, ureteral vascular compression syndromes, portal biliopathy). These syndromes can be unexpectedly diagnosed even in asymptomatic patients and the predisposing anatomic conditions can be incidentally discovered on imaging examinations performed for other indications, or they can manifest with atypical abdominal symptoms and acute complications, which may lead to significant morbidity if unrecognized. Although computed tomography (CT) is an accurate noninvasive technique for their detection, the diagnosis remains challenging due to the uncommon clinical presentation and often overlooked imaging features. Dynamic imaging may be performed in order to evaluate patients with inconstant symptoms manifesting in a specific position. The purposes of this paper are to review the CT imaging findings of abdominopelvic vascular compression syndromes, correlating with anatomical variants and to provide key features for the noninvasive imaging diagnosis.

Wilkie's syndrome, a missed opportunity

Wilkie’s syndrome is a rare cause of duodenal obstruction that can easily be missed at clinical practice. It is characterized by nausea, abdominal pain and vomit. It usually affects young adults, and it’s caused by a low aortomesenteric angle resulting in vascular compression of the duodenum. Symptoms could resemble many of the symptoms presented in a patient with a suspected eating disorder. The non-specificity of the clinical signs and symptoms can confuse, delay the diagnosis and expose the patient to potentially hazardous therapies. We report a case of a 20-year-old patient who presented to the emergency room with a history of intermittent vomiting and abdominal pain. He had been previously misdiagnosed with an eating disorder and received physiological therapy. Nonetheless, his pain persisted. After further evaluation with the use of imaging techniques, a low aortomesenteric angle was discovered. He underwent surgery and completely recovered. On follow up controls patient is well and he no longer had episodes of vomiting.

Evaluation of posterior nutcracker phenomenon using multisection spiral CT

AIM

To prospectively evaluate the epidemiological, anatomical classification, clinical importance, and radiological features of posterior nutcracker phenomenon (PNP) in patients examined with multisection spiral computed tomography (MSCT).

MATERIAL AND METHODS

Patients who underwent abdominal enhanced MSCT from January 2012 to July 2016 were evaluated retrospectively. Combined with the blood, normal biochemistry, and urine tests, patients were assessed retrospectively for renal vein diameter measurements, the compression ratio of blood vessels, gender differences, anatomical classification, percentage of proteinuria and haematuria, and clinical symptoms.

RESULTS

The study included 6,225 consecutive patients, PNP was observed in 2.06% involving the CLRV in 1.22% and retro-aortic left renal vein in 0.84%. The proportion of posterior nutcracker syndrome (PNS) was lower in PNP (17.2%). There was no difference by sex and age in the prevalence of PNP (p>0.05). In patients with urological symptoms, the number of type II abnormalities was more frequent than type Ia and type Ib abnormalities. Meanwhile, the number of type II abnormalities was frequent than the other two types. There was a significant difference between PNS and asymptomatic PNP (aPNP) in all measured values (p<0.001), the ratio was >4, especially in type II abnormalities (ratio >5.0).

CONCLUSIONS

PNP is a type of left renal vein entrapment. It is exceptionally rare and might be underdiagnosed. MSCT and measured values can be useful in diagnosis and recognition.

Degree of Left Renal Vein Compression Predicts Nutcracker Syndrome

Nutcracker syndrome (NS) refers to symptomatic compression of the left renal vein (LRV) between the abdominal aorta and superior mesenteric artery with potential symptoms including hematuria, proteinuria, left flank pain, and renal venous hypertension. No consensus diagnostic criteria exist to guide endovascular treatment. We aimed to evaluate the specificity of LRV compression to NS symptoms through a retrospective study including 33 NS and 103 control patients. The size of the patent lumen at point of compression and normal portions of the LRV were measured for all patients. Multiple logistic regression analyses (MLR) assessing impact of compression, body mass index (BMI), age, and gender on the likelihood of each symptom with NS were obtained. NS patients presented most commonly with abdominal pain (72.7%), followed by hematuria (57.6%), proteinuria (39.4%), and left flank pain (30.3%). These symptoms were more commonly seen than in the control group at 10.6, 11.7, 6.8, and 1.9%, respectively. The degree of LRV compression for NS was 74.5% and 25.2% for controls (p < 0.0001). Higher compression led to more hematuria (p < 0.0013), abdominal pain (p < 0.006), and more proteinuria (p < 0.002). Furthermore, the average BMI of NS patients was 21.4 and 27.2 for controls (p < 0.001) and a low BMI led to more abdominal pain (p < 0.005). These results demonstrate a strong correlation between the degree of LRV compression on imaging in diagnosing NS.

Superior Mesenteric Artery Syndrome in Patients with Crohn's Disease: A Description of 2 Cases Studied with a Novel Magnetic Resonance Enterography (MRE) Procedure

Case series

Patients: Female, 23 • Female, 27

Final Diagnosis: SMA syndrome

Symptoms: Abdominal pain • vomiting

Medication: —

Clinical Procedure: —

Specialty: Radiology

A 56-year-old female with celiac artery compression syndrome recovering through dietary changes and weight gain

Celiac artery compression syndrome is a rare condition characterized by extrinsic compression of the celiac artery by the median arcuate ligament, which leads to chronic, recurrent postprandial epigastric pain. Although traditional treatment of this syndrome involves laparotomy to release the median arcuate ligament, here we report on the rare case of a middle‐aged woman recovering with no specific treatment through her use of a food diary to change her diet which resulted in gradual weight gain. This suggests that in some cases, a conservative therapy for celiac artery compression syndrome should be tried before choosing surgical intervention.

Wilkie's syndrome

Superior mesenteric artery syndrome, also known as Wilkie's syndrome, is a rare vascular disease caused by the anomalous course of the superior mesenteric artery arising from the abdominal aorta with a smaller angle than the norm (<22°). The reduced angle compresses the structures situated between the aorta and the superior mesenteric artery, such as the duodenum and left renal vein; this can determine painful crises, intestinal subocclusions, and left varicocele. This syndrome can be congenital or acquired. The acquired type is more common and is generally caused by reduced perivascular fat surrounding the abdominal aorta and the superior mesenteric artery; this form is common among anorexic patients that have had a rapid weight loss. We present the case of a female patient who suffered from repeated postprandial vomiting and who lost 12 kg in 4 months. B-mode ultrasound imaging revealed evidence of a reduced angle between the aorta and the superior mesenteric artery, as found in Wilkie's syndrome. After diagnosis, the patient followed a high-calorie diet, and 2 months later an ultrasound scan proved the restoration of the aorto-mesenteric angle as a consequence of increased perivascular fat with regression of symptoms.