Validation of a Lymphedema Index Score Based on Noncontrast Magnetic Resonance Lymphangiography: Correlation with Clinical Staging and Indocyanine Green Lymphangiography

Background: A standardized lymphedema grading system is a prerequisite for accurately and objectively evaluating its severity, both preoperatively and postoperatively. The purpose of this study was to establish a clinically feasible noncontrast magnetic resonance lymphangiography (NMRL) protocol and a standardized scoring system for the evaluation of lymphedema. Methods and Results: From January 2020 to February 2021, 39 patients who had been clinically diagnosed with lymphedema and had undergone NMRL were included. The severity and circumferential extent of lymphedema were assessed using magnetic resonance imaging, and a combined index was devised as the sum of the product of the severity and extent scores determined at four different levels. A magnetic resonance imaging (MRI) stage was allocated based on the combined index score, its correlation with clinical indices was analyzed. The MR and clinical staging showed a percentage agreement of 85.9% and a kappa coefficient of 0.641, indicating moderate agreement (p < 0.001). Both the interlimb volume and interlimb impedance ratios differed significantly between groups (p < 0.001 for both). The correlation analysis revealed a significant correlation between the combined index score and the inter-limb volume ratio (r = 0.70, p < 0.001) and inter-limb impedance ratio at both 1 kHz (r = 0.71, p < 0.001) and 5 kHz (r = 0.71, p < 0.001). The interobserver agreement was moderate for the severity score, extent score, and combined score. Conclusion: The proposed standardized scoring system for evaluating lymphedema based on NMRL can reproducibly determine the severity and extent of lymphedema in both the upper and lower extremities, and correlates strongly with established clinical measures.

The Use of Noninvasive Imaging Techniques in the Assessment of Secondary Lymphedema Tissue Changes as Part of Staging Lymphedema

Too often, in clinical settings, the diagnosis and evolution of lymphedema is determined by limb circumference measurements and/or volume calculations. Besides the unrecognition of small lymphedemas, these techniques provide little to no information concerning the stage of the lymphedema. This latter is important in choosing appropriate treatment modalities and making an accurate prognosis. Different imaging techniques are described in literature giving insights in tissue changes due to lymphedema. The aim of this article is giving an overview of possible texture changes linked to the different edema stages, visualized with noninvasive imaging procedures like ultrasonography, computed tomography, dual-energy x-ray absorptiometry, or magnetic resonance imaging.

Histological findings compared with magnetic resonance and ultrasonographic imaging in irreversible postmastectomy lymphedema: a case study

Postmastectomy edema is a current complication after axillary lymph node dissection in cases of breast cancer treatment. Staging is important in order to select those patients who can benefit from complex physical therapy (CPT). Different imaging techniques can be used to evaluate the edema. Ultrasonography (US) is a harmless, cheap, and easily applicable technique to visualize the dermal and subcutaneous tissue, but interpretation of the obtained images is not always evident. The aim of this study was to compare ultrasound images of irreversible edema with tissue histology, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Ultrasonographic images of the edematous dermis show an homogeneous hypoechogenic dermal layer that appears on tissue histology to be less compact, due to the excess of fluid in the interstitium separating the collagen fibres and making it more transparent on light microscopy. MRI of the dermis gives a hyperintense signal, indicating the presence of fluid. In the subcutis, increase of the adipose tissue could be observed on US, MRI, and tissue histology. In the case of lymphedema, the area and perimeter of fat cells is significantly (p < 0.05) increased. Hypoechogenic areas near the muscle fascia are registered on US corresponding with epifascial fluid on MRI, and hyperechogenic branches are embedded within the adipose tissue, on tissue histology seen as large fibrotic septa enclosing adipose cells. MRI has a honeycomb picture corresponding with fluid bound to fibrosis.

MR imaging of primary, secondary, and mixed forms of lymphedema

PURPOSE

To describe the pathological features and assess the diagnostic information of different MR sequences in patients with primary, secondary, and mixed (phlebo-, lipophlebo-, or lipolymphedema) forms of lymphedema of the lower leg.

MATERIAL AND METHODS

In 26 patients with clinical diagnoses of primary (n=10), pure secondary (n=4), mixed (n=9) and combined secondary and mixed forms of lymphedema (n=3), MR imaging was performed with coronal and axial T1 SE, T2 TSE, fat-suppressed (SPIR) T2 sequences and axial T1 SE after i.v. injection of Gd-DTPA.

RESULTS

In 24 patients there was a honeycomb pattern in the subcutis with a signal intensity corresponding to fluid (n=11), fibrosis (n=3), or both (n=10). Five patients with primary lymphedema showed subfascial fluid accumulation. Dermal edema was noted in 23 patients. Fat or edema components in the muscles were mostly seen in patients with phlebolymphedema. The honeycomb pattern was best seen on coronal T1 images, and fluid accumulations on axial SPIR-T2 images. Fibrosis was only assessible from the T2 TSE sequence. Gd-DTPA did not improve the diagnostic information.

CONCLUSION

For evaluation of lymphedema and its mixed forms, an axial T2-weighted SPIR sequence in conjunction with a coronal T1 SE sequence are sufficient.

The MR appearance of volume overload in the lower extremities

PURPOSE

Our goal was to describe the MR findings of volume overload (VO) in the lower extremities.

METHOD

Fifteen individuals were studied, including eight healthy controls and seven patients with VO (four cardiac, three renal). MR evaluation included various SE techniques. Edema detection, localization, and symmetry were assessed subjectively. Relaxation time estimates were also made of the subcutaneous tissue, marrow, and three muscles.

RESULTS

Subcutaneous tissue was markedly edematous in seven of seven patients and asymmetric in four of seven, whereas marrow was normal in all patients. Muscle edema was mild and asymmetric in six and two of seven patients, respectively. Perifascial fluid collections were identified in six of seven patients.

CONCLUSION

Subcutaneous tissue edema is the dominant feature of VO in the lower extremities. Perifascial fluid is common but does not necessarily distribute symmetrically. Muscle edema is relatively mild. These findings should aid in identifying VO as the potential cause of swelling in patients with swollen legs.