The role of dynamic contrast-enhanced magnetic resonance imaging in the diagnosis and management of patients with vascular malformations

ACR Appropriateness Criteria® Soft Tissue Vascular Anomalies: Vascular Malformations and Infantile Vascular Tumors (Non-CNS)-Child

Soft tissue vascular anomalies may be composed of arterial, venous, and/or lymphatic elements, and diagnosed prenatally or later in childhood or adulthood. They are divided into categories of vascular malformations and vascular tumors. Vascular malformations are further divided into low-flow and fast-flow lesions. A low-flow lesion is most common, with a prevalence of 70%. Vascular tumors may behave in a benign, locally aggressive, borderline, or malignant manner. Infantile hemangioma is a vascular tumor that presents in the neonatal period and then regresses. The presence or multiple skin lesions in an infant can signal underlying visceral vascular anomalies, and complex anomalies may be associated with overgrowth syndromes. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Retroperitoneal capillary arteriovenous malformation mimicking a malignant neoplasm

Introduction

Retroperitoneal tumors account for 0.2% of all neoplasms. Among these tumors, retroperitoneal vascular malformations are particularly rare, with most previously reported cases being venous malformations.

Case presentation

A 72-year-old woman was diagnosed with a retroperitoneal tumor on abdominal computed tomography. The 27-mm diameter tumor was located away from the right kidney and major vessels in the right perirenal adipose tissue. Contrast-enhanced computed tomography revealed a heterogeneously enhanced tumor with well-defined borders. Dynamic contrast-enhanced magnetic resonance imaging revealed rapid enhancement in the arterial phase and a progressive filling-in pattern in the delayed phase. Although vascular malformation was suspected, a definitive diagnosis could not be established. The retroperitoneal tumor was excised laparoscopically for therapeutic and diagnostic purposes, and the histopathological diagnosis confirmed it as a capillary arteriovenous malformation.

Conclusion

Herein, we presented a rare case of retroperitoneal capillary arteriovenous malformation that was difficult to definitively diagnose preoperatively.

An imaging‑based diagnostic approach to vascular anomalies of the oral and maxillofacial region

The accurate diagnosis of vascular anomalies (VAs) is considered a challenging endeavor. Misdiagnosis of VAs can lead clinicians in the wrong direction, such as the performance of an unnecessary biopsy or inappropriate surgical procedures, which can potentially lead to unforeseen consequences and increase the risk of patient injury. The purpose of the present study was to develop an approach for the diagnosis of VAs of the oral and maxillofacial region based on computed tomography (CT), magnetic resonance imaging (MRI) and dynamic contrast-enhanced MRI (DCE-MRI). In the present study, the CT and MR images of 87 VAs were examined, and the following imaging features were evaluated: Detectability of the lesion, the periphery of the lesion, the inner nature of the lesion, the density of the lesion on CT, the signal intensity of the lesion on MRI, the detectability of phleboliths and the shape of the lesion. A total of 29 lesions were further evaluated using the contrast index (CI) curves created from the DCE-MRI images. A diagnostic diagram, which is based on the imaging features of VAs and CI curve patterns, was subsequently extrapolated. The results obtained demonstrated that the VAs were detected more readily by MRI compared with CT, whereas the detectability of phleboliths was superior when using CT compared with MRI. VAs showed a propensity for homogeneous isodensity on CT, whereas, by contrast, they exhibited a propensity for heterogeneous hyperdensity on CE-CT. VAs also showed a propensity for homogeneous intermediate signal intensity when performing T1-weighted imaging (T1WI), heterogeneous high signal intensity when performing short tau inversion recovery MRI, and heterogeneous high signal intensity when performing fat-saturated CE-T1WI. The CI curves of VAs were found to exhibit a specific pattern: Of the 29 CI curves, 23 (79.3%) showed early weak enhancement, followed by a plateau leading up to 400-600 sec. An imaging-based diagnostic diagram was ultimately formulated. This diagram can act as an aid for radiologists when they are expecting to find a VA, and hopefully serve the purpose of simplifying the diagnostic process. Taken together, the findings of the present study indicated that DCE-MRI may be considered a useful tool for the diagnosis of VAs.

Venous malformations

The often inexorable growth and expansion of congenital vascular malformations can result in substantial morbidity and, in some cases, premature death of these patients. Despite this, patients suffering from such lesions are often erroneously diagnosed and/or inadequately treated, due to a lack of expertise among primary care practitioners as well as specialists. Venous malformations are the most common type of congenital vascular malformations. Over the last two decades management of these lesions has significantly improved, predominantly due to the introduction and implementation of multidisciplinary team concept as well as improvement in diagnostic and treatment modalities. Relatively recently genetic studies are providing more insights into underlying pathophysiological mechanisms responsible for the development and progression of venous malformations and pharmacotherapy is becoming extensively evaluated for safety and efficacy in the treatment of these often challenging vascular lesions.

Superselective intranidal delivery of platinum-based high-density packing coils for treatment of arteriovenous malformations

Arteriovenous malformations (AVMs) classically feature an intervening nidus of poorly differentiated endothelium. The pillar of modern AVM treatment is intranidal delivery and deposition of various liquid embolic agents such as n-butyl cyanoacrylate, ethylene vinyl alcohol copolymer, and ethanol. These agents are cumbersome to prepare, deliver, and deploy and have been associated with complications related to limited delivery control, nonretrievability, frequent microcatheter exchanges, and nontarget embolization. Coils and other proximal occlusive agents have not been traditionally recommended as sole embolic agents for AVM treatment given the inherent lack of adequate AVM nidus penetration with previous coil technologies. In the present report, we have described a series of three patients with AVMs in whom newer generation, platinum-based, packing coils were used safely and effectively as the primary agent for superselective nidal penetration and embolization.

Magnet-targeted delivery of bone marrow-derived mesenchymal stem cells improves therapeutic efficacy following hypoxic-ischemic brain injury

Stem cell transplantation may represent a feasible therapeutic option for the recovery of neurological function in children with hypoxic-ischemic brain injury; however, the therapeutic efficacy of bone marrow-derived mesenchymal stem cells largely depends on the number of cells that are successfully transferred to the target. Magnet-targeted drug delivery systems can use a specific magnetic field to attract the drug to the target site, increasing the drug concentration. In this study, we found that the double-labeling using superparamagnetic iron oxide nanoparticle and poly-L-lysine (SPIO-PLL) of bone marrow-derived mesenchymal stem cells had no effect on cell survival but decreased cell proliferation 48 hours after labeling. Rat models of hypoxic-ischemic brain injury were established by ligating the left common carotid artery. One day after modeling, intraventricular and caudal vein injections of 1 × 10⁵ SPIO-PLL-labeled bone marrow-derived mesenchymal stem cells were performed. Twenty-four hours after the intraventricular injection, magnets were fixed to the left side of the rats’ heads for 2 hours. Intravoxel incoherent motion magnetic resonance imaging revealed that the perfusion fraction and the diffusion coefficient of rat brain tissue were significantly increased in rats treated with SPIO-PLL-labeled cells through intraventricular injection combined with magnetic guidance, compared with those treated with SPIO-PLL-labeled cells through intraventricular or tail vein injections without magnetic guidance. Hematoxylin-eosin and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining revealed that in rats treated with SPIO-PLL-labeled cells through intraventricular injection under magnetic guidance, cerebral edema was alleviated, and apoptosis was decreased. These findings suggest that targeted magnetic guidance can be used to improve the therapeutic efficacy of bone marrow-derived mesenchymal stem cell transplantation for hypoxic-ischemic brain injury. This study was approved by the Animal Care and Use Committee of The Second Hospital of Dalian Medical University, China (approval No. 2016-060) on March 2, 2016.

Safety and efficacy of foam sclerotherapy for treatment of low-flow vascular malformations in children

OBJECTIVE

Congenital vascular malformations are a heterogeneous group of lesions with the potential to cause significant lifelong morbidity in children. Diagnosis and treatment of these lesions may be complex and require a multidisciplinary approach. Sclerotherapy is widely used for the treatment of low-flow vascular malformations (LFVMs) as an alternative to surgical resection in adults; however, limited data of its use in a pediatric setting are available. The purpose of this study was to evaluate the efficacy and safety of sclerotherapy for pediatric LFVMs.

METHODS

In this retrospective study, we reviewed our multidisciplinary vascular malformations team database for all patients younger than 18 years treated for congenital vascular malformations from 2008 to 2017. Of these, patients with LFVM treated with foam sclerotherapy were included. Dynamic contrast-enhanced magnetic resonance imaging was used to select patients for sclerotherapy by the multidisciplinary team. Foam sclerotherapy was performed with either polidocanol or sodium tetradecyl sulfate. Patients' characteristics, including demographics, presenting symptoms, and anatomic location of malformation, were assessed. Outcomes included treatment response, number of procedures, and postprocedural complications.

RESULTS

The 61 patients with 61 LFVMs included 27 boys (44.3%) and 34 girls (55.7%), with mean age of 10.3 years (standard deviation, ± 5.3 years). The cohort included 32 venous (52.5%), 16 lymphatic (26.2%), and 8 mixed venous and lymphatic (13.1%) malformations along with 5 (8.2%) associated with Klippel-Trénaunay syndrome. Primary indications for intervention included pain and swelling (n = 12 [19.6%]), pain alone (n = 23 [37.7%]), swelling alone (n = 15 [24.6%]), functional impairment (n = 8 [13.1%]), and bleeding (n = 3 [4.9%]). Anatomic distributions varied, with 13 head and neck (21.3%), 5 truncal (8.2%), 10 upper extremity (16.4%), 27 lower extremity (44.3%), and 6 diffuse (9.8%). Among the head and neck lesions, 8 (13.1%) extended to the face; and of the extremity lesions, 5 (8.2%) extended to the hand and 17 (27.9%) to the foot. Overall, sclerotherapy resulted in significant improvement or complete resolution of symptoms in 53 patients (86.9%). Complications were observed in seven patients (11.4%); six cases (9.8%) of superficial skin ulceration resolved without intervention, and one infection (1.6%) required antibiotics. No patients experienced adverse hemodynamic consequences or venous thromboembolism.

CONCLUSIONS

This series of pediatric LFVMs, the largest of its kind to date, demonstrates that sclerotherapy with foam-based agents effectively reduces symptoms with an acceptable rate of complications. Further study is needed to determine the optimal sclerosing agents for individual subsets of LFVMs in the pediatric population.

Vascular Reconstruction of a Brachial Artery Aneurysm Proximally to an Arteriovenous Malformation

Brachial artery aneurysms and arteriovenous malformations (AVM) are limb-threatening vascular anomalies. This patient presented with a bilobed brachial artery aneurysm in the antecubital fossa proximally to an AVM arising from the dorsal interosseous and ulnar arteries that had been treated with endovascular embolization, leaving the hand solely supplied by the radial artery. The aneurysm continued to increase in size and imaging revealed concomitant thrombus. A femoral vein interposition graft was used to repair the aneurysm, and postoperatively, the patient retained full left arm function.

Role of imaging in the diagnosis of vascular malformations vascular malformations

Imaging evaluation of vascular malformations (VM) is paramount for proper diagnosis and treatment planning. These lesions often present as complex vascular masses with arterial, venous and lymphatic components, requiring the use of advanced imaging modalities for full anatomical characterization. Symptoms also depend of the location and flow characteristic of such lesions and range from: asymptomatic to severe forms of cardiac arteriovenous shunting. We present an overview of the diagnostic work-up of VM per most recent classification systems and describe imaging characteristics of such lesions at ultrasonography (US) and magnetic resonance imaging (MRI) as a diagnostic tool for work-up of such patients.

Morbidity and healthcare costs of vascular anomalies: a national study

PURPOSE

This study aimed to define morbidities and costs related to modern-day medical care for children with vascular anomalies.

METHODS

We reviewed the 2003-2009 Kids' Inpatient Database for pediatric patients (age < 21 years) hospitalized with hemangioma, arteriovenous malformation (AVM), or lymphatic malformation (LM). Patient characteristics, hospital complications, and hospital charges were compared by vascular anomaly type. Multivariable linear regression modeling was used to determine predictors of increasing hospital costs for patients with AVMs.

RESULTS

In total, 7485 pediatric inpatients with vascular anomalies were identified. Frequently associated complications included chronic anemia (4.0%), sepsis (4.6%), and hypertension (2.4%). Children with AVM had the highest rate of in-hospital mortality, compared to those with hemangiomas or LM (1.0% vs. 0.1% vs. 0.3%, p < 0.001). AVMs were also associated with the highest median hospital charge, more than twice the cost for hemangiomas or LM ($45,875 vs. $18,909 vs. $18,919; p < 0.001).

CONCLUSIONS

There is a significant rate of morbidity in children with vascular anomalies, most often from blood loss and infection. The greater cost of AVM care may be related to the higher mortality rate, associated complications, and complexity of procedures required treating them. Cost-effective management of vascular anomalies should target prevention and the early recognition of both chronic comorbidities and acute complications.

Arterial Spin-Labeling to Discriminate Pediatric Cervicofacial Soft-Tissue Vascular Anomalies

BACKGROUND AND PURPOSE

Differentiating major subtypes of cervicofacial vascular lesions is crucial for appropriate management. The aim of our study was to evaluate the performance of an MR imaging arterial spin-labeling perfusion sequence in discriminating pediatric cervicofacial soft-tissue vascular anomalies.

MATERIALS AND METHODS

We conducted a retrospective analysis of data from a prospectively maintained registry including pediatric patients at a tertiary pediatric center between January 2012 and January 2014. We included pediatric patients with a final diagnosis of soft-tissue vascular anomalies and an MR imaging, including an arterial spin-labeling sequence at presentation. We performed an analysis of lesion perfusion, blinded to clinical data, by using concurrent spiral 3D pseudocontinuous arterial spin-labeling (1.5T magnet; spiral matrix, 512 × 8 mm; postlabeling delay, 1025 ms). Lesional flow was recorded with calibrated intralesional ROIs. Perfusion characteristics were compared among lesion subtypes with the Mood Median test.

RESULTS

Among 840 patients screened, 46 matched the inclusion criteria and were included (median age, 1.45 years; interquartile range, 0.4-5.1 years; 27 females). Hemangiomas, including infantile hemangiomas (n = 18 patients) and noninvoluting (n = 2) and rapidly involuting (n = 1) congenital types, demonstrated marked hyperperfusion (median flow, 436 mL/min/100 g; interquartile range, 212.5-603 mL/min/100 g), significantly higher than that of lymphatic malformations (median, 22.5 mL/min/100 g; interquartile range, 16-60 mL/min/100 g; P < .001) or venous malformations (median, 25 mL/min/100 g; interquartile range, 15-66.5 mL/min/100 g; P = .003).

CONCLUSIONS

MR imaging arterial spin-labeling is a valuable tool for the assessment of soft-tissue vascular anomaly hemodynamics and for the classification of major lesion subtypes.

Distinguishing high-flow from low-flow vascular malformations using maximum intensity projection images in dynamic magnetic resonance angiography - comparison to other MR-based techniques

BACKGROUND

In addition to ultrasound, magnetic resonance imaging (MRI) is considered a suitable, non-invasive technique to assess the type and extent of vascular malformations. The distinction between low- and high-flow lesions is crucial because it determines appropriate patient treatment.

PURPOSE

To distinguish high-flow from low-flow lesions on the basis of the enhancement pattern on MIP images acquired from dynamic time-resolved MR angiography (MRA) and compare it with previously described MR-based methods.

MATERIAL AND METHODS

We examined 25 consecutive patients with previously diagnosed vascular malformations. Next, each malformation was classified as "high-flow" or "low-flow" using the following criteria: (i) findings on T1-weighted (T1W) and T2-weighted (T2W) imaging (signal voids, signal intensity); (ii) the time interval between the start of arterial enhancement and the onset of lesion enhancement (artery-lesion time); (iii) the time of maximum lesion enhancement; and (iv) analysis of the slope of the enhancement curve.

RESULTS

Of the 25 patients, seven had high-flow and 18 had low-flow malformations. Signal voids on spin-echo T1W images were observed only in four of seven high-flow malformations and in two of 18 low-flow malformations. Analysis of signal intensity on T2W images showed increased signal intensity in 17 of 18 low-flow malformations, and in two of seven high-flow lesions. Calculation of the artery-lesion time, maximum enhancement time, and slope revealed significant differences between the high- and low-flow groups.

CONCLUSION

In conclusion, the slope of the enhancement curve appears to be useful in distinguishing between high- and low-flow vascular malformations. Standardization of MR image evaluation criteria is essential.

High-pitch spiral CT with 3D reformation: an alternative choice for imaging vascular anomalies with affluent blood flow in the head and neck of infants and children

OBJECTIVE

To evaluate the feasibility of high-pitch spiral CT in imaging vascular anomalies (VAs) with affluent blood flow in the head and neck of infants and children.

METHODS

For patients with suspected VAs and affluent blood flow pre-detected by ultrasound, CT was performed with high-pitch mode, individualized low-dose scan protocol and three-dimensional (3D) reformation. A five-point scale was used for image quality evaluation. Diagnostic accuracy was calculated with clinical diagnosis with/without pathological results as the reference standard. Radiation exposure and single-phase scan time were recorded. Treatment strategies were formulated based on CT images and results and were monitored through follow-up results.

RESULTS

20 lesions were identified in 15 patients (median age of 11 months). The mean score of image quality was 4.13 ± 0.74. 7 patients (7/15, 46.67%) were diagnosed with haemangiomas, 6 patients (6/15, 40%) were diagnosed with venous malformations and 2 patients (2/15, 13.33%) were diagnosed with arteriovenous malformations. The average effective radiation doses of a single phase and of the total procedure were 0.27 ± 0.08 and 0.86 ± 0.21 mSv. The average scanning time of a single phase was 0.46 ± 0.09 s. After treatment, 13 patients (13/15, 86.67%) achieved excellent results, and 2 patients (2/15, 13.33%) showed good results in follow-up visits.

CONCLUSION

High-pitch spiral CT with an individualized low-dose scan protocol and 3D reformation is an effective modality for imaging VAs with affluent blood flow in the head and neck of infants and children when vascular details are needed and ultrasound and MRI could not provide the complete information.

ADVANCES IN KNOWLEDGE

This study proposes an alternative modality for imaging VAs with affluent blood flow.

Emerging role of contrast-enhanced MRI in diagnosing vascular malformations

Vascular malformations comprise a diverse and rare group of lesions which generally pose a formidable treatment challenge. Requisite for optimal surgical planning are imaging modalities capable of delineating involved anatomy and malformation flow characteristics. In this regard, we and others have purported the advantages of contrast-enhanced MRI. Here, we review the current body of literature regarding the emerging of role of contrast enhanced MRI for the management of vascular malformations.

The role of whole-body MRI in pediatric oncology

Pediatric whole-body (WB) magnetic resonance imaging (MRI) is an established technique that, with improved accessibility and advances in technology, is being used with increasing frequency for a wide variety of applications. The advantages of WB MRI (over other imaging modalities), particularly its lack of ionizing radiation (of particular concern in pediatric imaging due to children's increased sensitivity to ionizing radiation) and the ability of MRI to image the bone marrow, solid organs, and soft tissues with superior soft-tissue contrast resolution to other techniques, promise that WB MRI has great potential in conditions that are diffuse or multifocal. There is particular interest in its role in the field of pediatric oncology (eg, lymphoma, neuroblastoma, sarcoma, and Langerhans cell histiocytosis). The main disadvantages of WB MRI are its relatively long scanning times, artifacts from motion (requiring patient cooperation or general anesthesia), and limited specificity. However, advances in hardware and imaging techniques, including additional sequences (out-of-phase imaging, diffusion-weighted imaging, and contrast enhancement) are reducing the impact of some of these challenges.

Multidisciplinary treatment of extremity arteriovenous malformations

Congenital vascular malformations (CVMs) are a complex group of lesions that arise by embryologic dysmorphogenesis without increased endothelial proliferation that leads to structural and functional anomalies of the vascular system characterized by a wide range of presenting symptoms and often unpredictable clinical course. A recent advancement in the diagnostic and treatment modalities has resulted in a better understanding of the pathophysiology and natural history of CVMs and improved management of these lesions. The multidisciplinary approach and diagnostic algorithm used to distinguish high-flow (HFVM) from low-flow vascular malformations (LFVM) have been validated as clinically applicable for making an accurate anatomic and hemodynamic diagnosis of CVMs; they serve as a basis for proper treatment selection and significantly facilitate communication among different medical specialists. Dynamic contrast-enhanced magnetic resonance imaging is able to definitively distinguish HFVM from LFVM with accuracy of approximately 84%. In inconclusive cases, confirmatory angiography is required. Symptomatic, diffuse, extensive, macrocystic LFVMs and LFVMs that involve multiple tissue planes and vital structures are best treated with foam sclerotherapy. Primary surgical resection is the treatment of choice for localized, septated, and microcystic LFVMs. The management of HFVMs is characterized by multimodal treatment including preoperative embolization followed by complete surgical resection or sclerotherapy of the remaining venous component. Treatment of extensive CVMs is palliative and goal oriented. Implementation of the proposed diagnostic protocols and therapeutic algorithms in a multidisciplinary setting results in favorable outcomes with acceptable complication rates in this challenging patient population.

Ten frequently asked questions about MRI evaluation of soft-tissue vascular anomalies

OBJECTIVE

The objective of this article was to address 10 frequently asked questions that radiologists face when planning, performing, and interpreting an MRI study in a patient with a soft-tissue vascular anomaly.

CONCLUSION

MRI permits a comprehensive assessment of vascular anomalies. It is important for radiologists to be familiar with the classification and correct nomenclature of vascular anomalies as well as the MRI protocol and distinct imaging findings of the different vascular malformations and tumors.

Plexiform nerve sheath tumor or vascular malformation--role of advanced MR neurography and diffusion tensor imaging

The authors report a vascular malformation mimicking a plexiform peripheral nerve sheath tumor. Three Tesla magnetic resonance neurography with high-resolution anatomic and advanced functional diffusion tensor imaging was helpful in evaluating full extent of the lesion and characterizing its internal architecture.