MR imaging of symptomatic peripheral vascular malformations

The use of the flow-void sign on MRI: highly sensitive sign in detecting bone metastases from renal cell carcinoma

OBJECTIVE

To evaluate a range of pathologically proven malignant bone tumours, including primary bone sarcoma and metastatic bone lesions, referred to a tertiary referral centre for the presence of the flow-void sign on MR imaging.

MATERIALS AND METHODS

A retrospective search was performed using the radiology information system and oncology database in our institution to identify patients over the age of 40 years referred with a solitary bone lesion. Patients with a range of pathologically proven malignant bone tumours, including primary bone tumours and metastatic bone lesions, were included in the study. MRI images were reviewed for the presence of the flow-void sign. The presence and type of the flow-void sign were correlated with lesion size.

RESULTS

Two hundred and sixty-six cases were included in the study. Overall, the flow-void sign was identified in 40.9% of cases. The flow-void sign was most frequently seen in renal cell carcinoma metastasis (90.0%). The sign is highly sensitive (90%) for renal cell carcinoma metastases with a high negative predictive value (98.09%). When the flow-void sign is identified, the lesion is almost three times more likely to represent a renal cell carcinoma metastasis than any other malignant tumour in patients over the age of 40 years with a solitary bone lesion.

CONCLUSION

The flow-void sign is highly sensitive for renal cell carcinoma bone metastases and could negate the need for biopsy in patients with a known history of renal cell carcinoma or in whom an occult renal cell carcinoma is subsequently identified.

Deep learning-based differentiation of peripheral high-flow and low-flow vascular malformations in T2-weighted short tau inversion recovery MRI

BACKGROUND

Differentiation of high-flow from low-flow vascular malformations (VMs) is crucial for therapeutic management of this orphan disease.

OBJECTIVE

A convolutional neural network (CNN) was evaluated for differentiation of peripheral vascular malformations (VMs) on T2-weighted short tau inversion recovery (STIR) MRI.

METHODS

527 MRIs (386 low-flow and 141 high-flow VMs) were randomly divided into training, validation and test set for this single-center study. 1) Results of the CNN's diagnostic performance were compared with that of two expert and four junior radiologists. 2) The influence of CNN's prediction on the radiologists' performance and diagnostic certainty was evaluated. 3) Junior radiologists' performance after self-training was compared with that of the CNN.

RESULTS

Compared with the expert radiologists the CNN achieved similar accuracy (92% vs. 97%, p = 0.11), sensitivity (80% vs. 93%, p = 0.16) and specificity (97% vs. 100%, p = 0.50). In comparison to the junior radiologists, the CNN had a higher specificity and accuracy (97% vs. 80%, p <  0.001; 92% vs. 77%, p <  0.001). CNN assistance had no significant influence on their diagnostic performance and certainty. After self-training, the junior radiologists' specificity and accuracy improved and were comparable to that of the CNN.

CONCLUSIONS

Diagnostic performance of the CNN for differentiating high-flow from low-flow VM was comparable to that of expert radiologists. CNN did not significantly improve the simulated daily practice of junior radiologists, self-training was more effective.

Value of fat-suppressed T2-weighted imaging for predicting short-term pain relief after sclerotherapy for venous malformations in the extremities

PURPOSE

This study aimed to evaluate the value of fat-suppressed T2-weighted imaging (FS-T2WI) for predicting short-term pain relief after polidocanol sclerotherapy for painful venous malformations (VMs) in the extremities.

MATERIALS AND METHODS

This retrospective study included patients with painful VMs in the extremities between October 2014 and September 2021, had their first sclerotherapy without history of surgical therapy, and underwent magnetic resonance imaging before sclerotherapy. Pain relief was assessed 2 months after 3% polidocanol sclerotherapy and was categorized as follows: progression, no change, partial relief, or free of pain. The associations between pain relief and imaging features on FS-T2WI were analyzed.

RESULTS

The study included 51 patients. The no change, partial relief, and free of pain groups included 6 (11.8%), 25 (49.0%), and 20 (39.2%) patients, respectively. No patient experienced progressive pain. The lesion diameter was ≤ 50 mm in 13 (65.0%) patients in the free of pain group, whereas it was > 50 mm in all patients in the no change group (p = 0.019). The lesions showed well-defined margin in 15 (75.0%) patients in the free of pain group, whereas they showed ill-defined margin in 5 (83.3%) patients in the no change group (p = 0.034). The most common morphological type was cavitary in the free of pain group (14 [70.0%] patients), whereas there was no patient with cavitary type lesion in the no change group (p = 0.003). Drainage vein was demonstrated in 6 (100%), 22 (88.0%), and 11 (55.0%) patients in the no change, partial relief, and free of pain group, respectively (p = 0.011).

CONCLUSION

A lesion size of 50 mm or less, a well-defined margin, a cavitary type, and no drainage vein on FS-T2WI were significant features for predicting short-term pain relief after polidocanol sclerotherapy for painful VMs in the extremities.

Subcutaneous Granuloma Annulare vs. Subcutaneous Vascular Malformations in Children: A Diagnostic Challenge

OBJECTIVES

There are various subcutaneous lesions in children and often there is difficulty in obtaining an accurate diagnosis by non-invasive diagnostic procedures. Subcutaneous granuloma annulare (SGA) is a rare granulomatous disease that, even after imaging, is often mistaken for a low-flow subcutaneous vascular malformation (SVM). This study aimed to accurately identify clinical and imaging clues to distinguish SGA from low-flow SVM.

METHODS

We retrospectively analyzed complete hospital records of all children with a confirmed diagnosis of SGA and low-flow SVM who underwent MR imaging at our institution from January 2001 to December 2020. Their disease history, clinical and imaging findings, management, and outcome were evaluated.

RESULTS

Among 57 patients with granuloma annulare, we identified 12 patients (nine girls) with a confirmed SGA diagnosis who underwent a preoperative MRI. Their median age was 3.25 years (range 2-5 years). Of 455 patients diagnosed with vascular malformations, 90 had malformations limited to the subcutaneous area. Among them only 47 patients with low-flow SVM were included in the study and further analyzed. Our SGA cohort had a female predilection (75%) and a short history of lump appearance of 1.5 months. SGA lesions were immobile and firm. Before MRI, patients underwent initial evaluation by ultrasound (100%) and X-ray (50%). Surgical tissue sampling was performed in all SGA patients to establish a diagnosis. All 47 patients with low-flow SVM were diagnosed correctly by MRI. A total of 45 patients (96%) underwent surgical resection of the SVM. A careful retrospective review of imaging findings of patients with SGA and SVM showed that SGA present as homogenous lesions in the shape of an epifascial cap with a typical broad fascial base extending towards the subdermal tissue in the middle of the lesion. In contrast, SVMs always present with variable-sized multicystic or tubular areas.

CONCLUSIONS

Our study shows clear clinical and imaging differences between low-flow SVMs and SGA. SGA presents characteristically in the shape of a homogenous "epifascial cap," which distinguishes these lesions from multicystic heterogenous SVMs.

The Usefulness of MRI Dynamic Flow Sequences in Differentiating High- and Low-Flow Vascular Malformations

Peripheral arteriovenous malformations (PVMs) can be classified into high-flow malformations (HFVMs) and low-flow malformations (LFVMs). Adequate distinguishment is crucial for therapeutic decision and can be done using dynamic contrast-enhanced MRI (DCE-MRI). The main aim of this retrospective study was to determine the diagnostic value of quantitative DCE-MRI ratios for differentiation between HFVM and LFVM, their optimal cut-off points, and predictive values. DCE-MRI time-resolved angiography with stochastic trajectory (TWIST) examinations of 90 patients with PVMs were included [28 HFVM (31%), 62 LFVM (69%)]. The measurements of artery-lesion time, maximum lesion enhancement, slope of the enhancement curve, and maximum percentage increase of signal intensity (SI) were obtained. The optimal cut-offs for HFVMs calculated using the Youden index were: for slope of enhancement curve < 8.7 s (sensitivity of 86%, specificity of 89%), artery-lesion time ≤ 5.6 s (sensitivity of 89%, specificity of 77%), time to maximum enhancement ≤ 30 s (sensitivity of 94%, specificity of 100%), and maximum percentage enhancement of the lesion > 662% (sensitivity of 68%, specificity of 69%). To summarize, DCE-MRI is very valuable for differentiation between HFVM and LFVM, especially if quantitative measurements are done.

Imaging of peripheral vascular malformations - current concepts and future perspectives

Vascular Malformations belong to the spectrum of orphan diseases and can involve all segments of the vascular tree: arteries, capillaries, and veins, and similarly the lymphatic vasculature. The classification according to the International Society for the Study of Vascular Anomalies (ISSVA) is of major importance to guide proper treatment. Imaging plays a crucial role to classify vascular malformations according to their dominant vessel type, anatomical extension, and flow pattern. Several imaging concepts including color-coded Duplex ultrasound/contrast-enhanced ultrasound (CDUS/CEUS), 4D computed tomography angiography (CTA), magnetic resonance imaging (MRI) including dynamic contrast-enhanced MR-angiography (DCE-MRA), and conventional arterial and venous angiography are established in the current clinical routine. Besides the very heterogenous phenotypes of vascular malformations, molecular and genetic profiling has recently offered an advanced understanding of the pathogenesis and progression of these lesions. As distinct molecular subtypes may be suitable for targeted therapies, capturing certain patterns by means of molecular imaging could enhance non-invasive diagnostics of vascular malformations. This review provides an overview of subtype-specific imaging and established imaging modalities, as well as future perspectives of novel functional and molecular imaging approaches. We highlight recent pioneering imaging studies including thermography, positron emission tomography (PET), and multispectral optoacoustic tomography (MSOT), which have successfully targeted specific biomarkers of vascular malformations.

Imaging of intramuscular haemangiomas of the extremities

Intramuscular haemangiomas are benign soft tissue tumours that are more frequently seen in children and young adults. As they may be difficult to diagnose clinically, imaging has an important role in the detection, diagnosis and preoperative planning of these lesions. Haemangiomas of the extremities may be classified into capillary, cavernous, venous and mixed types, with or without an arteriovenous shunt, depending on the predominant vascular channels. Nonvascular components such as fat, smooth muscle, fibrous tissue and thrombus may also be present. This pictorial essay highlights the imaging features of intramuscular haemangiomas, with an emphasis on magnetic resonance imaging.

Vascular anomalies: Classification and management

Vascular anomalies are broadly classified into two major categories: vascular tumors and vascular malformations. Most vascular anomalies are caused by sporadic mosaic gene mutations, and recent genetic studies have advanced our understanding of the molecular pathways involved in their pathogenesis. These findings have suggested new therapeutic approaches to vascular anomalies, focusing on their pathogenetic mechanism. This chapter seeks to integrate an improved molecular understanding within the updated classification system of the International Society for Study of Vascular Anomalies. We emphasize the genetic, radiologic, and interventional aspects of diagnosis and management in hopes of allowing improved multidisciplinary collaboration surrounding these complex and interesting anomalies.

3T MRI of Peripheral Vascular Malformations: Characteristics and Comparison of Two Fat-Saturated sequences: Short Tau Inversion Recovery Versus Three-Dimensional High-Resolution Volume Interpolated Gradient Recalled Echo

PURPOSE

 To assess morphological and hemodynamic characteristics of peripheral vascular malformations on 3 T magnetic resonance imaging (MRI) including qualitative comparison of two fat-saturated sequences: short tau inversion recovery (STIR) and three-dimensional high-resolution volume interpolated gradient recalled echo (GRE).

MATERIALS AND METHODS

 During 9 months, 100 patients with suspected or known vascular malformations were prospectively assessed on a 3 T scanner using T2-weighted STIR and turbo spin echo (TSE), T1-weighted TSE, time-resolved contrast-enhanced magnetic resonance angiography (MRA) with interleaved stochastic trajectories (TWIST) and T1-weighted volume interpolated breath-hold examination (VIBE) after contrast enhancement. The analysis included signal behavior and morphologic and hemodynamic characteristics. Additionally, the image quality of the fat-saturated sequences was evaluated by 2 radiologists.

RESULTS

 86 patients (14 dropouts; 57 female, 29 male; mean age 26.8 years, age range 1-56) were analyzed. 22 had high-flow and 64 low-flow malformations, including 14 with a lymphatic component. In 21 of 22 patients with high-flow malformations, typical characteristics (flow voids, hyperdynamic arteriovenous fistula, dilated main/feeder-arteries and draining veins) were documented. Patients with low-flow malformations had phleboliths in 35 cases, fluid-fluid levels in 47 and dilated draining veins in 23. Lymphatic malformations showed peripheral contrast enhancement of cyst walls in the volume interpolated GRE. The comparison of fat-saturated sequences showed significantly better results of the volume interpolated GRE in all categories except the presence of artifacts which were significantly reduced in the STIR (p < 0.05).

CONCLUSION

 3 T MRI with MRA provides detailed morphological and hemodynamic information of different types of peripheral vascular malformations. Contrast-enhanced high-resolution volume interpolated GRE proved superior to STIR in differentiating morphologic features and to be diagnostic in the differentiation of lymphatic parts and joint involvement.

KEY POINTS

  · 3 T MRI with MRA offers detailed information about vascular malformations.. · Fat-saturated MRI provides especially information about morphological characteristics, extent and tissue involvement.. · Volume interpolated GRE proved superior in almost all categories compared to STIR.. · Volume interpolated GRE showed more artifacts.. · Volume interpolated GRE additionally allows differentiation of lymphatic parts and evaluation of joint involvement..

CITATION FORMAT

· Höhn F, Hammer S, Fellner C et al. 3T MRI of Peripheral Vascular Malformations: Characteristics and Comparison of Two Fat-Saturated sequences: Short Tau Inversion Recovery Versus Three-Dimensional High-Resolution Volume Interpolated Gradient Recalled Echo. Fortschr Röntgenstr 2021; 193: 446 - 458.

MRI evaluation of soft tissue vascular malformations

Background:

Soft tissue vascular malformations are not uncommonly encountered in clinical practice and are often mistaken for other pathologies. Vascular anomalies are divided into vascular tumors and malformations. Vascular malformations progressively increase in size with increasing age and are classified into low-flow (venous, lymphatic, veno-lymphatic, capillary and capillary venous) and high-flow malformations (arteriovenous malformations (AVM) and arteriovenous fistula (AVF)) depending on the presence or absence of arterial flow.

Aim:

Aim of this study is to evaluate the Magnetic resonance imaging (MRI) features of the soft tissue vascular malformations and to classify the lesions depending on flow pattern.

Materials and Methods:

A total of 52 patients of soft tissue vascular malformations were included in this study over a period of 3 years. All patients underwent detailed clinical examination and dynamic post contrast MRI evaluation. Doppler and ultrasound were done as an adjunct.

Results:

There were 31 females and 21 male patients with age ranging from 9 to 34 years. In total 33 venous, 11 lymphatic, 8 veno-lymphatic malformations were seen. No case of high-flow malformation was seen. Majority of the lesions involved the head and neck region and the extremities. Fat saturated T2WI, STIR, and 3D dynamic post contrast sequences were found to be the most useful MRI sequences.

Conclusion:

MRI is the modality of choice for evaluating the soft tissue vascular malformations. It depicts the extent of the lesion, classifies the lesions into low or high flow and helps in treatment planning.

Percutaneous treatment of orofacial vascular malformations

The aim of this study was to evaluate the efficacy of fluoroscopy-guided percutaneous injection of bleomycin as the primary treatment for low-flow vascular malformations. A total of 34 patients (mean (range) age 24 (8-51) years) with orofacial vascular lesions were treated in the Department of Interventional Radiology and Maxillofacial Surgery. There were 20 low-flow venous malformations, 11 lymphatic malformations, and three of mixed type. All patients were treated by fluoroscopy-guided percutaneous injection of a mixture of bleomycin (mean (range) 15 (5-15)mg) and a radio-opaque agent (Ultravist^® (iopromide), Bayer)/session. The number of sessions ranged from one to six. The clinical response was complete in 21 patients, obvious in nine, and of clinical benefit in four. Patients were reviewed within the first week, third week, and at three-month periods until 24 months. There were no serious complications such as pulmonary fibrosis. Fluoroscopy-guided intralesional injection of bleomycin should be considered as the first-line treatment for lymphatic malformations because it is effective and reliable with few complications.

Magnetic Resonance (MR) Imaging of Vascular Malformations

Vascular malformations pose a diagnostic and therapeutic challenge due to the broad differential diagnosis as well as common utilization of inadequate or inaccurate classification systems among healthcare providers. Therapeutic approaches to these lesions vary based on the type, size, and extent of the vascular anomaly, necessitating accurate diagnosis and classification. Magnetic resonance (MR) imaging (MRI) is an effective modality for classifying vascular anomalies due to its ability to delineate the extent and anatomic relationship of the malformation to adjacent structures. In addition to anatomical mapping, the complete evaluation of vascular anomalies includes hemodynamic characterization. Dynamic time-resolved contrast-enhanced MR angiography provides information regarding hemodynamics of vascular anomalies, differentiating high- and low-flow vascular malformations. Radiologists must identify the MRI features of vascular malformations for better diagnosis and classification.

Foam Sclerotherapy of Venous Malformations

Venous malformations may occur either as localized or segmental lesions. Radiologic imaging defines the extent of involvement but magnetic resonance imaging is the best modality: it gives a bright hypersignal on T2-weighted spin-echo sequences.

During a 30-month period, 1427 patients were investigated for venous disorders and 1% were found to have venous angiomata (9 women and 5 men). The age range was 15 to 76 years (mean 30.8 ± 18.6 years). Foam was produced by the Tessari technique using 1% or 2% concentration of polidocanol. The duplex Doppler was used for ultrasound guidance to insure intravenous flow of foam and to monitor effects of treatment.

A goal of pain-free healing of ulcers or cosmetic improvement was set for each patient. The mean number of treatments was 3.6 ± 2.8 (range 1–10). Pain-free healing was achieved in patients with non-healing ulcerations and cosmetically, all of the patients were improved. Sclerosant foam is useful in treating low-flow venous malformations.

Venous malformations: clinical diagnosis and treatment

Venous malformation (VM) is the most common type of congenital vascular malformation (CVM). They are present at birth and are often symptomatic, causing morbidity and pain. VMs can be challenging to diagnose and are often confused with hemangioma in terminology as well as with imaging. An accurate clinical history and cross-sectional imaging are critical for diagnosis and for devising management. This manuscript will review imaging approaches to diagnosing VMs and current treatment strategies.

Low-Flow Arterialized Venous Malformations of the Orbit

PURPOSE

Orbital vascular malformations are classified by their hemodynamic properties, either high or low flow. Low-flow lesions may be simple venous, lymphatic, or combined lymphaticovenous malformations. The authors report a series of cases in which predominantly low flow, venous lesions were unexpectedly noted to have arterial feeders.

METHODS

A retrospective chart review of patients identified by the authors as having orbital varices with arterial components was conducted. The authors identified 7 such cases. After careful review, 2 cases were excluded due to inconclusive neuroradiographic findings. The authors review the clinical, radiologic, histopathologic, and surgical information from the remaining 5 cases and discuss their clinical significance.

RESULTS

All 5 cases were most consistent with variceal lesions: 3 as clinically distensible lesions and 2 as thrombosed lesions. Additional arterial feeder vessels were noted by angiography (3) or intraoperative visualization (2). The arterial contribution varied from faint vessels to distinct branches of the ophthalmic artery. Ages ranged from 13 to 61 years without predilection for gender. Treatments consisted of excision, embolization, and observation. Two poignant cases are highlighted: the first illustrating that an angiogram in isolation of its clinical picture can be misleading and result in treatment intervention with undue risk, and the second illustrating that inadequate treatment of unrecognized arterial components may contribute to recurrences.

CONCLUSIONS

Low-flow orbital variceal lesions may have less prominent, arterial components. This type of combined arterialized venous malformation is largely unrecognized in the ophthalmic literature. Correct identification of these lesions is critical in providing safe, effective, and durable treatment.

Magnetic Resonance Angiography of the Upper Extremity

The magnetic resonance angiography (MRA) toolbox includes a wide array of versatile methods for diagnosis and therapy planning in patients with a variety of upper extremity vascular pathologies. MRA can provide excellent image quality with high spatial and high temporal resolution without the disadvantages of ionizing radiation, iodinated contrast, and operator dependency. Contrast-enhanced techniques are preferred for their robustness, image quality, and shorter scan times. This article provides an overview of the available MRA techniques and a description of the clinical entities that are well suited for evaluation with contrast-enhanced MRA.

Ethanol and/or radiofrequency ablation to treat venolymphatic malformations that manifest as a bulging mass in the head and neck

AIM

To evaluate the efficacy of ultrasound (US)-guided ethanol ablation (EA) and radiofrequency ablation (RFA) for treating venolymphatic malformations (VLM) of the head and neck.

MATERIALS AND METHODS

US-guided EA and/or RFA were performed on 17 patients with VLM of the head and neck. Computed tomography (CT) or magnetic resonance imaging (MRI) was used to locate the cranial nerves and salivary gland ducts that were close to targets, and these were avoided during the procedures. Treatment response was assessed using volume reduction and cosmetic grading scoring.

RESULTS

Nine VLMs were located close to the functional structures: Stensen's duct (n=3), cranial nerve branch (n=3), or both (n=3). All patients demonstrated >50% volume reduction, except one patient with a microcystic lymphatic malformation that was abutting the facial nerve. Median cosmetic grading scores improved from 4 to 1 (p<0.001).

CONCLUSION

US-guided EA and/or RFA are effective and safe treatment methods in patients with VLMs of the head and neck. Treatment selection of EA and/or RFA could be performed based on the composition of VLMs as assessed at CT and MRI.

Imaging features of an intraosseous arteriovenous malformation in the tibia

Primary intraosseous arteriovenous malformations (AVMs) are rare and have only been occasionally reported. We herein report a histologically proven case of primary intraosseous AVM in the tibia, which mimicked a fibrous tumour on radiography. This presentation carries a risk of triggering acute large haemorrhage through unnecessary biopsy. In intraosseous AVM, the magnetic resonance (MR) imaging features typical of a soft tissue AVM are absent, making diagnosis difficult. In this report, peculiar MR features in the presence of a connecting vessel between the normal deep venous system of the lower extremity and the tumour provide a clue for the early diagnosis of primary intraosseous AVM.

Peripheral limb vascular malformations: an update of appropriate imaging and treatment options of a challenging condition

Peripheral vascular malformations encompass a wide spectrum of lesions that can present as an incidental finding or produce potentially life- or limb-threatening complications. They can have intra-articular and intraosseous extensions that will result in more diverse symptomology and present greater therapeutic challenges. Developments in classification, imaging and interventional techniques have helped to improve outcome. The onus is now placed on appropriate detailed preliminary imaging, diagnosis and classification to direct management and exclude other more common mimics. Radiologists are thus playing an increasingly important role in the multidisciplinary teams charged with the care of these patients. By fully understanding the imaging characteristics and image-guided procedures available, radiologists will be armed with the tools to meet these responsibilities. This review highlights the recent advances made in imaging and the options available in interventional therapy.

Vascular anomalies: A pictorial review of nomenclature, diagnosis and treatment

Vascular anomalies, including vascular malformations and tumors, are frequently straightforward to detect; however, accurate diagnosis and appropriate treatment are often challenging. Misdiagnosis of these lesions can lead clinicians in the wrong direction when treating these patients, which can have unfavorable results. This review presents an overview of the classification systems that have been developed for the diagnosis of vascular lesions with a focus on the imaging characteristics. Pictorial examples of each lesion on physical examination, as well as non-invasive and minimally invasive imaging are presented. An overview of the endovascular treatment of these lesions is also given. In some cases, vascular anomalies may be associated with an underlying syndrome and several of the most commonly encountered syndromes are discussed. Understanding of the classification systems, familiarity with the treatment options and knowledge of the associated syndromes are essential for all physicians working with this patient population. The approach to the described entities necessitates an organized multi-disciplinary team effort, with diagnostic imaging playing an increasingly important role in the proper diagnosis and a combined interventional radiologic and surgical treatment method showing promising results.

Open repair, endovascular repair, and conservative management of true splenic artery aneurysms

OBJECTIVE

True splenic artery aneurysms (SAAs) are a rare but potentially fatal pathology. For many years, open repair (OPEN) and conservative management (CONS) were the treatments of choice, but throughout the last decade endovascular repair (EV) has become increasingly used. The purpose of the present study was to perform a systematic review and meta-analysis evaluating the outcomes of the three major treatment modalities (OPEN, EV, and CONS) for the management of SAAs.

METHODS

A systematic review of all studies describing the outcomes of SAAs treated with OPEN, EV, or CONS was performed using seven large medical databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to ensure a high-quality review. All articles were subject to critical appraisal for relevance, validity, and availability of data regarding characteristics and outcomes. All data were systematically pooled, and meta-analyses were performed on several outcomes, including early and late mortality, complications, and number of reinterventions.

RESULTS

Original data of 1321 patients with true SAAs were identified in 47 articles. OPEN contained 511 patients (38.7%) in 31 articles, followed by 425 patients (32.2%) in CONS in 16 articles and 385 patients (29.1%) in EV in 33 articles. The CONS group had fewer symptomatic patients (9.5% vs 28.7% in OPEN and 28.8% in EV; P < .001) and fewer ruptured aneurysms (0.2% vs 18.4% in OPEN and 8.8% in EV; P < .001), but no significant differences were found in existing comorbidities. CONS patients were usually older and had smaller-sized aneurysms than patients in the OPEN and EV groups. The only identified difference in baseline characteristics between OPEN and EV was the number of ruptured aneurysms (18.4% vs 8.8%; P < .001). OPEN had a higher 30-day mortality than EV (5.1% vs 0.6%; P < .001), whereas minor complications occurred in a larger number of the EV patients. EV required more reinterventions per year (3.2%) compared with OPEN (0.5%) and CONS (1.2%; P < .001). The late mortality rate was higher in patients treated with CONS (4.9% vs 2.1% in OPEN and 1.4% in EV; P = .04).

CONCLUSIONS

EV of SAA has better short-term results compared with OPEN, including significantly lower perioperative mortality. OPEN is associated with fewer late complications and fewer reinterventions during follow-up. Patients treated with CONS showed a higher late mortality rate. Ruptured SAAs are predictors of a significantly higher perioperative mortality compared with nonruptured SAAs in the OPEN and EV groups.

A case of scrotal venous malformation mimicking a failed varicocelectomy

A 21-year-old man presented to interventional radiology department with several years of left scrotal pain, which exacerbated by prolonged standing and walking. The patient had undergone a left varicocelectomy at the age of 10, after which he had a persistent scrotal mass. As he grew older, the left scrotal mass continued to increase in size, and symptoms progressively worsened. Physical examination revealed a non-tender, firm left scrotal mass which remained unchanged in size after Valsalva manoeuvres. Initial ultrasound examination revealed an extratesticular, intrascrotal mass with minimal internal flow. MRI revealed a heterogeneously enhancing, low-flow venous malformation centred in the midscrotum involving multiple tissue planes. Two sessions of percutaneous sclerotherapy failed to relieve his pain. Three months after the second sclerotherapy, the patient underwent surgical resection. At the time of his postoperative visit, his left scrotal pain had significantly improved and pain with prolonged standing and walking had resolved completely.

[Klippel-Trenaunay syndrome and pregnancy: difficult choice of delivery from a case and a review of the literature]

Klippel-Trenaunay syndrome (SKT) is a rare disease characterized by cutaneous haemangiomas, capillary malformations venous (venous varicosities), bone and soft tissue hypertrophy affecting one or more limbs. It is often associated with hemorrhagic and thrombotic complications, especially during pregnancy. Vulvovaginal anomalies at risk of bleeding may occur in late trimester of pregnancy, affecting delivery. The terms of delivery depends on the severity of vascular malformations and the experience of the obstetrician. We report the case of a woman in labor at 38 weeks gestation with a SKT with involvement of the left leg up to the corresponding large lip. She presented after vaginal delivery a severe post-partum hemorrhage (2000mL) secondary to vaginal lacerations requiring sutures and supplemented by arterial embolization. A multidisciplinary approach is required at delivery.

Renal cell carcinoma initially presenting as an arteriovenous malformation: a case presentation and a review of the literature

We describe a case of a patient who presented with hematuria and was diagnosed with a renal arteriovenous malformation (AVM). Transcatheter arterial embolization subsequently was performed on this lesion multiple times. Follow-up imaging demonstrated that the AVM was masking an underlying, rapidly growing renal cell carcinoma (RCC). We describe the pathological and radiographic characteristics of AVMs and RCC. We describe the strengths and weaknesses of computed tomography (CT) and magnetic resonance imaging (MRI) to detect and characterize RCC and AVM. We recommend initial and follow-up MR imaging in patients with an AVM to establish a baseline, monitor treatment response, and survey lesions for underlying and obscured malignancy.

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.

The role of MRI in diagnostic algorithm of cervicofacial vascular anomalies in children

Background:

Vascular anomalies are usually diagnosed through their clinical picture and history. The purpose of this study was to assess the role of MR imaging in initial assessment of cervicofacial vascular anomalies in children.

Material/Methods:

Twenty pediatric patients with vascular anomalies located in the cervicofacial region underwent MRI examination in our department. Images were evaluated for lesion detectability and its signal characteristics (on T1w, T2w images with fat suppression and contrast enhanced T1w sequences); the extent of the lesions and surrounding tissue involvement were also assessed.

Results:

In the studied group MR images revealed all anomalies and provided information of their anatomic extent and invasion of surrounding anatomic structures. Nine hemangiomas and six venous malformations were found among studied patients. Two children had multiloculated lesions corresponding to lymphatic malformations. One examination visualized a lesion consisting mainly of dilated vascular channels with an apparent feeding artery, which was consistent with arteriovenous malformation. Two remaining lesions were mixed malformations. Nine patients had lesions limited to subcutaneous tissue. Two masses infiltrated bone structures. There was muscle involvement found in nine cases.

Conclusions:

MR imaging is a well-established method for detection and monitoring of vascular anomalies in children. With ultrasound used mostly for initial diagnosis and additional flow assessment, angiography viewed as an invasive therapeutic method and computed tomography used only in specific situations due to its high irradiation dose, magnetic resonance is the best imaging method used in differential diagnosis and topographical characterization of vascular malformations and tumors of cervicofacial area in pediatric patients. Noninvasively and without irradiation, it enables evaluation of the extent and characteristics of lesions and planning proper therapeutic strategy.

Venous malformation and haemangioma: differential diagnosis, diagnosis, natural history and consequences

Venous malformation (VM) is the most common form of congenital vascular malformation (CVM). VM presents at birth as an inborn vascular defect and never disappears/regresses spontaneously through the rest of life; it will continue to grow slowly at a rate that is proportional to the growth rate of the body. Haemangioma is not a vascular malformation but one of the vascular tumours originating from the endothelial cells; it develops after birth mostly in the infantile/neonatal period with a distinctive growth cycle: a proliferation phase of early rapid growth followed by an involutional phase of slow regression. Although the vascular malformation and vascular tumour belong to the ‘vascular anomaly’ together, both conditions are fundamentally different not only in their anatomical, histological and pathophysiological findings but also in their clinical courses. Therefore, an appropriate differential diagnosis of the VM is mandated not only from other kinds of CVMs but also from ‘genuine’ haemangioma. Appropriate diagnosis and assessment of VMs can be made based on clinical presentation and a proper combination of basic non-invasive studies in general but the presence of a mixed lesion involving other types of CVM lesions and the type of VM lesion, extratruncular and truncular, will dictate the need for further work-up with additional non- to less-invasive study or angiography. Otherwise, angiography is usually reserved for therapeutic planning and treatment.

Magnetic resonance imaging of muscle disease: a pattern-based approach

Magnetic resonance imaging (MRI) is a powerful tool to assess the severity, distribution, and progression of muscle injury and disease. However, a muscle's response to a pathological insult is limited to only a few patterns on MRI, and findings can be nonspecific. A pattern-based approach is therefore essential to correctly interpret MR studies of abnormal muscle. In this article we review the anatomy, function, and normal MRI appearance of skeletal muscle. We present a classification scheme that categorizes abnormal MR appearances of muscle into 4 main pattern descriptors: (1) distribution; (2) change in size and shape; (3) T1 signal; and (4) T2 signal. Each category is further subdivided into the various patterns seen on MRI. Such an approach allows one to systematically assess abnormal findings on muscle MRI studies and ascertain clues to the diagnosis or differential diagnosis, particularly when findings are correlated with the clinical context.

Peripheral vascular tumors and vascular malformations: imaging (magnetic resonance imaging and conventional angiography), pathologic correlation and treatment options

Vascular anomalies are classified into vascular tumors (infantile hemangioma) and vascular malformations. Vascular malformations are divided into slow flow and high flow subtypes. Magnetic resonance imaging helps in classification and assessing extent and distribution. Conventional angiography also known as digital subtraction angiography is pivotal in assessment of fine vascular details and treatment planning. Imaging correlates well with histopathology. We review recent development in imaging techniques of various vascular anomalies most of which are affecting the peripheral system which potentially may broaden understanding of their diagnosis, classification and treatment.

Imaging of Cystic and Cyst-like Lesions of the Mediastinum with Pathologic Correlation

Cystic masses of the mediastinum are a heterogenous group of asymptomatic or symptomatic, congenital, infectious, or neoplastic lesions. For early and correct diagnosis, evaluation, and optimal patient management of cystic mediastinal masses in infants, children, or adults imaging plays an important role. A non-invasive and sensitive imaging modality is an efficient and cost-effective tool. Multidetector computed tomography (MDTC) with volumetric acquisition provides fast acquisition of high resolution images and multiplanar reconstruction. Both 2D and 3D imaging in mediastinal imaging help in surgical planning and assessing resectability of mediastinal lesions. MR imaging has many advantages over other modalities for detecting and identifying cystic, or fluid-filled mediastinal masses, because of its intrinsic high soft tissue contrast and direct multiplanar imaging capabilities. However, histological tissue analysis may be required to differentiate a cystic lesion from other cyst-like or low-attenuation lesions.

High temporal and spatial resolution imaging of peripheral vascular malformations

PURPOSE

To assess the performance of a recently developed 3D time-resolved CE-MRA technique, Cartesian Acquisition with Projection-Reconstruction-like sampling (CAPR), for accurate characterization and treatment planning of vascular malformations of the periphery.

MATERIALS AND METHODS

Twelve patient studies were performed (eight female, four male; average age, 33 years). The protocol consisted of three-dimensional (3D) time-resolved CE-MRA followed by a single late phase T1-weighted acquisition. Vascular malformations were imaged in the forearm, hand, thigh, and foot. Imaging evaluation was performed for accurate characterization of lesion type, identification of feeding and draining vessels, involvement with surrounding tissue, overall quality for diagnosis and treatment planning, and correlation with conventional angiography.

RESULTS

Time-resolved CE-MRA allowed for characterization of malformation flow and type. Feeding and draining vessels were identified in all cases. Overall quality for diagnosis and treatment planning was 3.58/4.0, and correlation with conventional angiography was scored as 3.89/4.0.

CONCLUSION

The CAPR time series has been shown to portray the temporal dynamics and structure of vascular malformations as well as the normal vasculature with high quality. CAPR time-resolved imaging is able to accurately characterize high and low flow lesions, allowing for pretreatment lesion assessment and treatment planning. Delayed imaging is important to capture complete filling of very slow flow vascular malformations.

MR imaging of soft-tissue vascular malformations: diagnosis, classification, and therapy follow-up

Vascular malformations and tumors comprise a wide, heterogeneous spectrum of lesions that often represent a diagnostic and therapeutic challenge. Frequent use of an inaccurate nomenclature has led to considerable confusion. Since the treatment strategy depends on the type of vascular anomaly, correct diagnosis and classification are crucial. Magnetic resonance (MR) imaging is the most valuable modality for classification of vascular anomalies because it accurately demonstrates their extension and their anatomic relationship to adjacent structures. A comprehensive assessment of vascular anomalies requires functional analysis of the involved vessels. Dynamic time-resolved contrast material-enhanced MR angiography provides information about the hemodynamics of vascular anomalies and allows differentiation of high-flow and low-flow vascular malformations. Furthermore, MR imaging is useful in assessment of treatment success and establishment of a long-term management strategy. Radiologists should be familiar with the clinical and MR imaging features that aid in diagnosis of vascular anomalies and their proper classification. Furthermore, they should be familiar with MR imaging protocols optimized for evaluation of vascular anomalies and with their posttreatment appearances. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.315105213/-/DC1.

Low-dose contrast-enhanced time-resolved MR angiography at 3T: diagnostic accuracy for treatment planning and follow-up of vascular malformations

AIM

To assess the accuracy of low-dose contrast-enhanced time-resolved 3T magnetic resonance angiography (MRA) for the morphological and functional assessment of vascular malformations (VM), and to evaluate its diagnostic potential for the depiction of treatment-induced changes.

MATERIALS AND METHODS

Twenty-five patients with known VM underwent MRA to evaluate the location and extent of lesions and their haemodynamic characteristics. Three-dimensional (3D) T1-weighted time-resolved sequences were acquired following the administration of 0.05mmol/kg of gadobenate dimeglumine. VM were classified according to their morphology and haemodynamic characteristics. All patients thereafter underwent conventional angiography to confirm the diagnosis and to treat the lesions (embolization or sclerotherapy). Follow-up MRA was performed 30 days after treatment to assess morphological and functional changes. A visual analogue scale (VAS) was used to clinically assess the severity of symptoms before and after therapy.

RESULTS

Based on haemodynamic characteristics, VM were classified as predominantly arterial [4 (16%)], artero-venous [19 (76%)] or venous [2 (8%)]. Twenty-three (92%) lesions were classified as high-flow VM and two (8%) as low-flow VM. Intralesional thrombosis was present in 17 (68%) lesions before therapy and in 10 lesions (40%) after therapy. The median VAS scores were 5±1 before treatment and 4±2 after treatment. Very good correlation (Spearman's correlation coefficient: rho=0.87; p=0.000) was noted between the reduction of lesion size on follow-up MRA and pain relief as assessed by VAS.

CONCLUSION

Low-dose contrast-enhanced time-resolved 3T MRA can be used to define morphological and functional aspects of VM accurately during treatment planning and follow-up, and can identify post-therapy changes that positively correlate with treatment outcome.

Endovascular management of high-flow arteriovenous malformations

This article describes the various methods of endovascular management of high-flow arteriovenous malformations. Concepts of patient management and various therapies for vascular malformations are discussed. Nontraumatic acquired arteriovenous malformations, arteriovenous fistulae, and endovascular treatment of arteriovenous malfromations are described.

A Step-by-Step Practical Approach to Imaging Diagnosis and Interventional Radiologic Therapy in Vascular Malformations

Within vascular anomalies, vascular malformations are those present at birth that grow with the patient and exhibit abnormal dilated vascular channels lined by mature endothelium. Vascular tumors, the other group of vascular anomalies, demonstrate endothelial hypercellularity. Vascular malformations are further divided into low-flow varieties (capillary, venous, and lymphatic malformations) and high-flow varieties (arteriovenous malformation and fistula). All malformations exhibit a predictable group of clinical patterns that vary in severity and rate of progression. The interventional radiologist must incorporate this clinical data with characteristic ultrasound and magnetic resonance findings to arrive at a diagnosis. One must then decide in a multidisciplinary fashion, based on objective clinical criteria and image-based morphology, if the patent is a candidate for intervention. Sclerotherapy is a technique used to treat vascular malformations whereby an endothelial-cidal agent is introduced into the endoluminal compartment to initiate vascular closure. The high flow rate of an arteriovenous malformation requires the incorporation of superselective transarterial, direct, and transvenous access with flow reduction techniques to deliver adequate dose of sclerosant and embolic to the nidus. Satisfactory outcomes are seen in over half of all malformations patients. Similar treatment-related complications are seen between malformations but are lowest in lymphatic and highest in arteriovenous malformations.

Usefulness of contrast-enhanced three-dimensional MR angiography using time-resolved imaging of contrast kinetics applied to description of Extracranial Arteriovenous Malformations: initial experience

PURPOSE

The purpose of this study was to evaluate the usefulness of contrast-enhanced three-dimensional MR angiography using time-resolved imaging of contrast kinetics (TRICKS-MRA) to demonstrate extracranial arteriovenous malformations (E-AVMs).

MATERIALS AND METHODS

TRICKS-MRA was performed in 33 patients (adults; n = 30, children; n = 3) with E-AVMs. Four different scan protocols were arranged based on the size of E-AVM, and serial images were acquired from the start of contrast injection with a time frame ranging from 1.2 to 7.1s. Demonstration of feeding arteries and drainage veins, and the extent of nidus was qualitatively graded using a three-point scale. In sixteen patients who underwent DSA 3 days to 15 months after TRICKS-MRA, the comparability of TRICKS-MRA to DSA was evaluated using a three-point scale. In each category, score of 3 or excellent was defined as the positive result.

RESULTS

Demonstration of the feeding arteries, the drainage veins, and the extent of nidus were graded as excellent in 68%, 65%, and 58% of the patients, respectively. Comparability of TRICKS-MRA to DSA was excellent in 75%, 88%, and 88% of the sixteen patients who underwent DSA.

CONCLUSION

TRICKS-MRA is a feasible and useful vascular imaging technique to provide time-resolved analysis of angioarchitecture of E-AVMs.

Vascular malformations

Vascular malformations are rare but important skin disorders in children, which often require multidisciplinary care. The goal of this article is to orient pediatricians to the various types of vascular malformations. We discuss the clinical characteristics, diagnostic criteria, and management of capillary, venous, arteriovenous, and lymphatic malformations. Associated findings and syndromes are also discussed briefly.