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

Soft Tissue Vascular Anomalies of the Extremities: A Proposed Diagnostic Approach

This narrative review aims to summarise the classification of vascular anomalies, their clinical presentation, and their radiological features to propose a diagnostic algorithm to approach patients with suspected soft tissue vascular anomalies of the extremities. The management of vascular anomalies necessitates a multidisciplinary approach. Clinical presentation and physical examination are sufficient in most cases to achieve a correct diagnosis. This is especially true for small congenital lesions of the skin and subcutaneous tissue. Imaging is used for accurate characterization of these lesions, especially in cases of atypical or vague clinical presentation, and to assess extension in cases of lesions that are larger and localized in deeper tissues.

MRI-based radiomics in distinguishing Kaposiform hemangioendothelioma (KHE) and fibro-adipose vascular anomaly (FAVA) in extremities: A preliminary retrospective study

OBJECTIVE

To investigate the pretreatment differentiation between Kaposiform hemangioendothelioma (KHE) and fibro-adipose vascular anomaly (FAVA) in extremities of pediatric patients. To build and validate an MRI-based radiomic model.

METHOD

In this retrospective study, we obtained imaging data from 43 patients. We collected and compared clinical information, sketched region of interest (ROI), and extracted radiomic features from fat-suppressed T2-weighted (T2FS) images of the two cohorts of 30 and 13 patients respectively (training versus testing cohort 7:3). To select features, we used two sample t-test and the least absolute shrinkage and selection operator (LASSO) regression. The support vector machine (SVM) classification was constructed and evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

Thirty patients with KHE and 13 patients with FAVA in the extremities were included. Most lesions demonstrated low to intermediate signal intensity on T1-weighted images and hyperintense signals on T2-weighted ones. They also showed similar traits pathologically. Initially, 107 radiomic features were acquired and then three were finally selected. The support vector machine (SVM) model was able to differentiate the two anomalies from each other with an area under the curve (AUC) of 0.807 (95%CI 0.602-1.000) and 0.846 (95%CI 0.659-1.000) in training and testing cohort, respectively.

CONCLUSION

The derived radiomic features were helpful in differentiating KHE from FAVA. A model which contained these features might further improve the performance and hopefully could serve as a potential tool for identification.

Sonography of abdominal wall vascular malformation: a case report and review of the literature

Vascular anomalies are classified as vascular tumors (VT) and vascular malformations (VM). VTs are divided according to their clinical behavior, while VMs are classified according to their flow characteristics, histopathologic features, and associations with other anomalies. Sonography emerges as the diagnostic imaging method of first choice for assessing abdominal wall disorders and masses, thus representing a valuable tool for the diagnosis and follow-up of abdominal wall VMs. In this review, we report a case of abdominal wall arteriovenous malformation (AVM) in a 17-year old and briefly discuss the cases of abdominal wall VMs.

[Foot and ankle tumours : Part I: overview of incidence, diagnosis and staging of pedal tumours]

CLINICAL ISSUE

Foot and ankle tumours are rare. Part I of this paper provides a survey about tumour distribution regarding age and location of benign and malignant bone and soft tissue tumours.

STANDARD RADIOLOGICAL METHODS

All diagnostic radiological procedures are used for the diagnostic work-up of pedal tumours, in particular plain radiography, MRI, and ultrasonography.

METHODICAL INNOVATIONS

Dual-energy CT proves to be a valuable (differential) diagnostic tool in identifying urate dihydrate crystals.

PERFORMANCE

There are no reliable numbers available on accuracy of the aforementioned diagnostic procedures regarding tumour detection and identification. This is particularly true for soft tissue tumours which are small and well-defined, thus requiring histological clarification.

ACHIEVEMENTS

To evaluate pedal tumours correctly and reasonably, a full range of radiological diagnostics should be employed. Neither plain radiography alone nor a stand-alone MRI examination-depending on the tumour site-are sufficient to characterize such tumours including staging.

PRACTICAL RECOMMENDATIONS

Plain radiography remains the first-choice imaging modality. Ultrasonography is superior to reliably detect and identify ganglion cysts. MRI, however, continues to remain the upmost diagnostic modality of choice for evaluating foot and ankle tumours. CT possesses unchallanged diagnostic power to assess osseous changes. Bone scintigraphy (including SPECT-CT) and FDG-PET imaging are used when multifocal distribution or metastatic disease are suspected or to detect avidity of the pedal lesions, respectively.

Efficacy of Percutaneous Sclerotherapy in Low Flow Venous Malformations - A Single Center Series

Purpose

We analyzed results of percutaneous sclerotherapy for venous malformations (VMs) in head, neck and extremities.

Materials and Methods

Thirty-five patients with head and neck and extremities VM treated by sclerotherapy with bleomycin and sodium tetradecyl sulphate (STS) were retrospectively reviewed. A pre-treatment magnetic resonance imaging was done for all patients to diagnose the lesion. Each lesion received 1 to 11 sessions (average, 2.7; standard deviation [SD], 2.03). We evaluated percentage reduction in swelling size and a Likert scale review of subjective feelings of the patients.

Results

Sixteen had a complete obliteration; by sclerotherapy alone (n=13) and surgery after a 75% reduction (n=3). Ten patients had a significant reduction up to 75% and three patients by 50%. Four had a minimal decrease with reduction of 25% or less. Follow-up duration of the patients varied from a minimum of 6 months up to 3 years (average, 15.7 months; SD, 7.8 months). Of all patients, three refused further treatment and were lost to follow-up, while another two were referred to a dermatologist. Thirteen patients reported feeling excellent after the sessions. Eight patients claimed to feel slightly better compared to before the sessions started. Only three patients complained of feeling the same before and after the sessions. None of the patients still in follow-up have reported a recurrence of a lesion thus far.

Conclusion

Sclerotherapy using bleomycin and STS as sclerosants is a safe and effective primary treatment for VMs in the head and neck as well as in extremities.

Soft-tissue vascular malformations and tumors. Part 2: low-flow lesions

Vascular malformations and tumors, also known as "vascular anomalies", comprise an extensive variety of lesions involving all parts of the body. Due to a lack of a complete understanding of the origin and histopathology of such lesions, this field has been traditionally obscured by the use of an unclear nomenclature. Knowledge of the classification and clinical and imaging characteristics of this group of lesions is paramount when managing these patients. The objective of this series of two articles is to review the current classification of vascular anomalies, to describe the role of imaging in their diagnosis, to summarize their distinctive histopathologic, clinical and imaging features, and to discuss the treatment options. High-flow lesions were discussed in the first article of this series. In this second article, we will focus on low-flow lesions, including complex syndromes with associated low-flow malformations.

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.

Knee MRI: Vascular Pathology

OBJECTIVE

Patients who undergo knee MRI for presumed musculoskeletal disease can have unexpected vascular findings or pathology in the imaged field. Some vascular processes are limb threatening and affect treatment planning and patient outcome.

CONCLUSION

Unexpected vascular findings on knee MRI can range from incidental to symptomatic and can include such processes as variant anatomy, aneurysm, traumatic injury, and neoplasm. The assessment for vascular pathology should be a key component of every radiologist's search pattern when evaluating knee MRI.

Radiographic findings associated with vascular anomalies

Imaging of patients with vascular tumors and malformations has been sufficiently refined to answer pertinent questions when making treatment decisions in this challenging subgroup of pediatric patients. The imaging modalities at hand include conventional radiography, Doppler ultrasound, and magnetic resonance imaging with time-resolved, contrast-material enhanced magnetic resonance angiography. This review article will focus on the characteristic imaging features of some focal and diffuse vascular lesions, which have been classified by their clinical history and physical exam, and further labeled as a vascular tumor or slow-flow versus high-flow vascular malformation based on the updated classification system proposed by the International Society for the Study of Vascular Anomalies. The recent advances in knowledge regarding the biology of these vascular anomalies have led to increased awareness of the current nomenclature. Moreover, with better understanding of the imaging features, the radiologist has become a key player in the multidisciplinary approach offered at various institutions where appropriate treatment algorithms and interventional strategies are put together. This is crucial in avoiding misdiagnosis and improper management.

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.

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.