Sonographic evaluation of pediatric localized scleroderma: preliminary disease assessment measures

Abstract

Background: Our earlier work in the ultrasonograpy of localized scleroderma (LS) suggests that altered levels of echogenicity and vascularity can be associated with disease activity. Utrasound is clinically benign and readily available, but can be limited by operator dependence. We present our efforts to standardize image acquisition and interpretation of pediatric LS to better evaluate the correlation between specific sonographic findings and disease activity.

Methods: Several meetings have been held among our multi-center group (LOCUS) to work towards standardizing sonographic technique and image interpretation. Demonstration and experience in image acquisition were conducted at workshop meetings. Following meetings in 2007, an ultrasound measure was developed to standardize evaluation of differences in echogenicity and vascularity. Based upon our initial observations, we have labeled this an ultrasound disease activity measure. This preliminary measure was subsequently evaluated on over 180 scans of pediatric LS lesions. This review suggested that scoring levels should be expanded to better capture the range of observed differences. The revised levels and their definitions were formulated at a February 2009 workshop meeting. We have also developed assessments for scoring changes in tissue thickness and lesion size to better determine if these parameters aid evaluation of disease state.

Results: We have standardized our protocol for acquiring ultrasound images of pediatric LS lesions. A wide range of sonographic differences has been seen in the dermis, hypodermis, and deep tissue layers of active lesions. Preliminary ultrasound assessments have been generated. The disease activity measure scores for altered levels of echogenicity and vascularity in the lesion, and other assessments score for differences in lesion tissue layer thickness and changes in lesion size.

Conclusions: We describe the range of sonographic differences found in pediatric LS, and present our efforts to standardize ultrasound acquisition and image interpretation for this disease. We present ultrasound measures that may aid evaluation of disease state. These assessments should be considered a work in progress, whose purpose is to facilitate further study in this area. More studies are needed to assess their validity and reliability.

Figure 1

14 year old girl with linear scleroderma affecting her left arm; portion shown is from her upper arm. She has chronic atrophy from long standing disease (11 years), with persistent signs of disease activity including erythema and pruritis. Ultrasound shows varying patterns of echogenicity differences in the lesion, with no difference found in the dermis (dermis echogenicity = 0), mildly increased echogenicity in the hypodermis in a patchy pattern (hypodermis echogenicity = 1), and decreased echogenicity in the muscle (deep tissue echogenicity = -1). Ultrasound allows facile measurement of tissue thickness. Cursors were placed at tissue boundaries, using the highest point of the humeral bone as a landmark for the measurements. The lesion dermis is thinner than the normal dermis (measurement 2 (0.14 cm) vs 1 (0.21 cm), respectively; dermis tissue thickness score 1). The lesion hypodermis is mildly thicker than the normal hypodermis (measurement 4 (0.82 cm) vs 3 (0.75 cm), respectively; hypodermis tissue thickness score -1). The lesion muscle is thinner than the normal muscle (measurement 6 (0.93 cm) vs 5 (1.38 cm), respectively; deep tissue tissue thickness score 2). B = bone, D = dermis, H = hypodermis, and M = muscle. Arrowheads indicate boundaries of dermis, while arrows indicate boundaries of hypodermis and muscle. Large tick marks on x and y axis = 1 cm.

Figure 2

17 year old girl with generalized morphea that began over 13 years earlier. She has lesions on her back, abdomen, arms, and leg. Most lesions show dyspigmentation and mild tissue loss, but her back lesions have increased warmth. Ultrasound of a back lesion shows thinning of the dermis and hypodermis, and an increase in lesion dermal echogenicity (dermis echogenicity = 1). There are highly echogenic horizontal bands in the hypodermis layer of both the normal and lesion hypodermis layers. The echogenicity of these bands is increased in the lesion, as is the base level of hypodermal echogenicity (hypodermis echogenicity = 2). The lesion muscle shows a patchy increase in echogenicity compared to the normal muscle (deep tissue echogenicity = 1). Arrowheads indicate boundaries of dermis, while arrows indicate boundaries of hypodermis and muscle.

Figure 3

14 year old boy with circumscribed deep morphea of the infraorbital region for 2 years. His lesion has shown deeper pigmentation changes and recent increased tissue loss. There is marked thinning of the hypodermis layer. The echogenicity of the hypodermis is markedly increased, and greater than the echogenicity of the normal dermis (hypodermis echogenicity = 3). The echogenicity of the lesion dermis is also increased (dermis echogenicity = 1). D = dermis, H = hypodermis. Arrowheads indicate boundaries of dermis, while arrows indicate boundaries of hypodermis.

Figure 4

15 year old girl with linear scleroderma of her left leg that has progressed over the past three years. Her calf lesion shows erythema, warmth, and continuing tissue loss. Ultrasound shows an increase in lesion hypodermal vascularity; there are a few small color Doppler signals in both the lesion and normal hypodermis, and one large color Doppler signal in the lesion hypodermis (hypodermal vascularity = 1). D = dermis, H = hypodermis. Arrowheads indicate boundaries of dermis, while arrows indicate boundaries of hypodermis.

Figure 5

15 year old girl with over an 8-year history of localized scleroderma. She initially presented with linear scleroderma of one hand that extended up her arm. There has been recent extension of this lesion to her upper back, and circumscribed morphea lesions have developed on her chest and thigh. Ultrasound image shown is of her upper arm, which had chronic atrophy and hyperpigmentation, but also mild erythema. There is increased vascularity in the lesion muscle, with over 10 discrete color Doppler signals in this layer versus none in the normal muscle. The deep tissue vascularity is scored as 2 because there are over two-fold more color Doppler signals in the lesion compared to normal; the vascularity is not scored as 3 because all of the lesion color Doppler signals are of a similar small size. The normal hypodermis has over two-fold more color Doppler signals than the lesion in this image, giving a lesion hypodermal vascularity score of -1. D = dermis, H = hypodermis, and M = muscle. Arrowheads indicate boundaries of dermis, while arrows indicate boundaries of hypodermis.

Figure 6

6 year old girl with linear scleroderma of her calf for the past two years. The lesion is warm and mildly violaceous. There is loss of hypodermal fat in the lesion (left side of lesion image). The lesion muscle layer has increased vascularity with at least 4 more large color Doppler signals on the lesion side compared to the normal muscle (deep tissue vascularity = 3). The Doppler signal seen on the left hand side in the normal hypodermis layer is artifact. B = bone, D = dermis, H = hypodermis, and M = muscle. Arrowheads indicate boundaries of dermis, while arrows indicate boundaries of hypodermis and muscle.

Figure 7

6 year old girl with a four year history of linear scleroderma of her left arm and hand. Her lesion has extended to her upper back, and she has new lesions on her face and chest. The imaged area is the volar surface of hand above 5^th metacarpal bone, which shows chronic atrophy including shortening of this portion of her hand, but no signs of activity. The patient complained of pain in this area. There is abundant color Doppler signal in both the normal and lesion area, but more vascularity is seen in the lesion hypodermis and muscle layers. The lesion hypodermis shows a large area of contiguous color Doppler signal that encompasses at least 20% of the surface area of the imaged hypodermis (hypodermal vascularity = 3). There are 2 large color Doppler signals in the lesion muscle and none in the normal muscle, giving a deep tissue vascularity score of 2. B = bone, D = dermis, H = hypodermis, and M = muscle. Arrowheads indicate boundaries of tissue layers.

Figure 8

8 year old girl with linear scleroderma of her lower leg with a four year history of active disease. A single rather than dual screen image was obtained to allow measurement of lesion size. The boundaries of the area of complete loss of hypodermal fat were identified directly on the viewing monitor, with cursors placed at boundary points to determine the width of the area of fat loss (3.79 cm). B = bone, D = dermis, H = hypodermis, and M = muscle. Arrowheads indicate boundaries of merged dermis and hypodermis, while arrows indicate boundaries of hypodermis and muscle.