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Year : 2000  |  Volume : 10  |  Issue : 4  |  Page : 233-236
Evaluation of skin lesions with color doppler and spectral analysis


Dept of Radiology Imaging & Dernatology, UCMS & GTB Hosp,Dilshad Garden, Delhi - 110 095, India

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   Abstract 

Objectives : Skin lesions in twenty-four patients were evaluated with the help of color Doppler and spectral analysis in an effort to characterize the ultrasonographic differentiating features of various benign and malignant lesions. Material and Methods : A 7.5 MHz linear array small parts probe was used on a Philips P700 scanner, a real time scanner with color Doppler facility. Twenty-four patients with skin lesions were evaluated with gray scale US, duplex and color flow Doppler US. The patients were referred from our dermatology department without a clinical diagnosis. The age of the patients ranged from 15-65 years. Gray scale US findings of the lesions were obtained and compared with the normal skin on the contralateral region of the body. The lesions were evaluated for vascularity with color flow Doppler imaging. Maximum systolic and end diastolic velocities were measured and RI was calculated. The lesion was examined from two and more regions in order to minimize the error and average values of velocities were obtained. The Doppler settings used were (VFW) variable focal windowing in which depth was selected according to the size of the lesion and maximum (EE) edge enhancement for optimum visualization of the lesion. Results : Twenty-four patients were studied. Out of twenty-four patients seventeen patients showed benign lesions and seven patients showed malignant lesions. Seven patients out of twenty four patients showed color flow, four in benign lesions and three in malignant lesions. Seven patients out of twenty-four (30%) showed color flow pattern. Four out of seventeen benign lesions (24%) showed color flow pattern. Three out of seven malignant lesions (42%) showed color flow pattern. The thickness of the lesions was measured and ranged between 0.27-2.21 cm. The diameter of the lesions was between 0.67-3.40 cm. In our study we found that the thickness and diameter of the lesions did not play a significant role in the color flow patterns obtained. The RI values obtained were found to be overlapping in benign and malignant lesions. However the mean peak systolic velocities obtained from benign and malignant skin lesions were 5.75 cm/sec and 35.40 cm/sec per second respectively with a significant P-value =0.000 (t-test). There was a significant difference between the peak systolic velocities obtained between the benign and malignant lesions. The mean end diastolic velocities of benign and malignant lesions were 3.00 cm/sec and 15.67 cm/sec respectively. The P-value=0.005 (t-test) was also significant. Conclusions : The Majority of the skin tumors are benign and therefore there is a need for a non-invasive method that aids the selection of malignant tumors for their removal. Color Doppler US and spectral analysis of skin lesions are a useful compliment to skin biopsy for differentiating between benign and malignant skin lesions. Our study proves that the flow velocities of skin lesion are very significant in differentiating between benign and malignant skin lesions and also work as a supporting diagnostic tool in doubtful and challenging cases. However excision biopsy is the gold standard for analysis of such lesions.

Keywords: Color Doppler, skin lesions, spectral analysis

How to cite this article:
Pushkarna R, Bhargava SK, Baruah M C, Mohanty S, Pushkarna N. Evaluation of skin lesions with color doppler and spectral analysis. Indian J Radiol Imaging 2000;10:233-6

How to cite this URL:
Pushkarna R, Bhargava SK, Baruah M C, Mohanty S, Pushkarna N. Evaluation of skin lesions with color doppler and spectral analysis. Indian J Radiol Imaging [serial online] 2000 [cited 2019 Jun 15];10:233-6. Available from: http://www.ijri.org/text.asp?2000/10/4/233/30568
With the availability of high frequency transducers, USG is being very often used in soft tissues, musculoskeletal system, chest diseases and small parts.

The preliminary report of dermatologic USG in terms of skin thickness measurements and study of melanomas is available in literature [1],[2]. However the skin is the largest organ of body with an ability to produce an enormous variety of benign and malignant lesions, which have overlapping complaints and presentation. Excision biopsy is the gold standard [3]. The majority of the skin lesions are benign. This project was undertaken to characterize skin lesions non-invasively with the help of color Doppler spectral analysis.

High frequency and high resolution US is being increasingly used to evaluate skin lesions, particularly melanomas for their invasive nature prior to cryosurgery, laser surgery or radiotherapy. It is also useful for assessment of skin thickness in lesions such as psoriasis, morphea and keratosis before and after therapy [4].


   Materials and Methods Top


Twenty four patients referred from the dermatology OPD were evaluated in our department with a color Doppler scanner. US scans were performed on a Philips P700 scanner with color Doppler facility with a 7.5 MHZ linear array small parts probe using liberal amount of jelly to increase the distance between the lesions and the transducer due to the superficial nature of the lesions. The Doppler settings used were (VFW) variable focal windowing in which depth was selected according to the size of the lesion and maximum (EE) edge enhancement for optimum visualization of the lesion. The Doppler angle was kept between 35-450 and flow settings optimized to delineate slow to medium flow. The maximum frame rate was 57 FPS (frames per second) with adequate wall filtration; the frame rate was adjusted according to the flow observed. The nature of the lesions was later confirmed on skin biopsy and histological correlations.


   Results Top


Sonography images were obtained for all patients. The thickness of the lesion measured ranged from 0.27-2.21 cm and diameter 0.67 - 3.40 cm. No vascularity was demonstrated in the non-nodular lesions. All tumor lesions presented as hypoechogenic masses in the dermis [Figure - 1]. With the help of color Doppler imaging, vascularity was demonstrated in four out of 17 benign lesions (24%) [Figure - 2] and three out of seven malignant lesions (42%) [Figure - 3]. The mean peak systolic velocities of benign and malignant lesions were 5.75 cm/sec and 35.40 cm/sec with a significant P-value=0.000 (t-test). The mean end diastolic velocities were 3.00 cm/sec and 15.67 cm/sec (P-value = 0.005 significance). No flow was seen in two basal cell carcinomas [Figure - 4]


   Discussion Top


Diagnostic USG is being used for all areas of medicine and its use has been extended to dermatology [5]. The advent of high frequency and high resolution transducers (7.5-20MHz) have further helped in the evaluation of skin lesions with respect to their extent and preoperative thickness of skin, in nodular lesion like cysts, hemangiomas, lipomas, lymphangiomas, dermatofibromas, in infiltrative lesions such as morphea, psoriasis and keratosis before and after therapy. The use has also been extended to the assessment of burns and monitoring of wound healing [6],[7],[8].

Ultrasound of the skin is a noninvasive assessment of multiple areas of the skin. In addition, USG may appreciate aspects of skin that would not otherwise be recorded by visual observation or by histologic examination. Use has been applied to study of aging and monitoring inflammatory responses. Edwards et al using A mode found a good correlation between US measurements and histopathology [9]. These investigators found US useful in distinguishing between basal cell carcinoma, mole and dermatofibroma based on analysis of such ultrasonic parameters as amplitudes, density, regularity and attenuation. Reali et al used 7.5 MHz USG preoperatively to obtain information on the thickness of melanomas. USG was used preoperatively to determine the extent of excision required to fully remove a lesion. A study conducted by Renato Nessi et al using USG for nodular and infiltrative lesions of the skin and subcutaneous tissues concluded that a reliable diagnosis of benign and malignant skin lesions could not be made on US. They also thought that USG cannot replace clinical examination or histological section and that sonography is only complimentary to clinical examination, mainly to assess the liquid or solid content of a mass and to measure its size.

Tumor growth is related to newly formed in-growing vessels as well as existing host vessels in the tumor. The tumor vessels are often primitive vascular channels, which lack smooth muscle, consisting of an endothelial layer and connective tissue alone. Due to thism high systolic, low resistance flow is expected in most neoplasms [10].

Twenty-four patients referred from our dermatology department were evaluated. The US findings showed that the lesions were hypoechogenic in nature [Figure - 1]. There was a significant difference between the peak systolic and end-diastolic velocities of benign and malignant lesions. We demonstrated medium to high peak systolic velocities and high diastolic velocities in 42% (3/7) malignant lesions, which were consistent with neoplastic vasculature [Figure - 3]. In 24% (4/17) of benign lesions we demonstrated low systolic and low diastolic velocities [Figure - 2]. They were found to be significant (t-test). However the thickness and diameter of the lesions did not play a significant role. There is no significant distinctive feature between various types of primary malignant skin tumors like basal cell carcinoma and squamous cell carcinoma and only excisional biopsy can prove the diagnosis. In our study we could demonstrate high systolic velocities in squamous cell carcinoma and metastatic lesions in the scalp from a thyroid neoplasm which were consistent with neoplastic vasculature. The two basal cell carcinomas evaluated did not show color flow due to their non-aggressiveness [Figure - 4].

Color Doppler USG is an excellent non-invasive modality for the assessment of blood flow in tumoral lesions of skin and allows reliable differentiation between benign and malignant lesions if the blood flow is demonstrated and measured. We suggest that a larger study in this respect may be done in future

To the best of our knowledge this seems to be the first study in our country on the use of color Doppler imaging in differentiating between benign and malignant skin lesions. Due to the free availability and non-invasive nature of color Doppler this may serve as a useful supporting diagnostic tool in doubtful and challenging cases.

 
   References Top

1.Alexandre H, Miller DL, Determining the skin thickness with pulsed ultrasound. J Invest Dermatol 197; 72: 17-19.   Back to cited text no. 1    
2.Reali UM, Santucci M, Paoli G, et al . The use of high-resolution ultrasound on preoperative evaluation of cutaneous malignant melanoma thickness. Tumori 1989; 75:452-455.   Back to cited text no. 2    
3.Harland C. C, Bamber J.C, Gusterson B.A et al . High frequency, high resolution B-scan ultrasound in the assessment of skin tumors. British J. of Dermatology 1993; 128: 525-532.   Back to cited text no. 3    
4.Vaillant L, Berson M, Machet L, et al . Ultrasound imaging of the psoriatic skin: a noninvasive technique to evaluate treatment of psoriasis. Int. J. of Dermatology 1990; 33: 786-790.   Back to cited text no. 4    
5.Gropper CA, Stiller MJ, Shaupack JL, Driller J et al . Diagnostic high-resolution in ultrasound in dermatology. International journal of Dermatology 1993;32 L4 243-250.   Back to cited text no. 5    
6.Fornage B. D, Mc Garven M.H. Duvic M, et al , Imaging of skin with 20 MHz USG, Radiology 1993; 69-76F.   Back to cited text no. 6    
7.Nessi R, Benchini PL, et al , USG of nodular and infiltrative lesions of the skin and subcutaneous tissues. J Clin Ultrasound 1990;18:103-109.   Back to cited text no. 7    
8.Baldassara S, Offidani A. M, Solbiati L. US of skin and soft tissues In: Solbiati L, Rizzatto Geds, Ultrasound of Superficial Structures. New York Churchill Livingstone, 1995: 261-279.   Back to cited text no. 8    
9.Edwards C, A1-aboosi MM, Marks R. The use of A-scan ultrasound in the assessment of small skin tumours. Br Dermatol 1989; 121: 297-304.   Back to cited text no. 9    
10.Taylor KJW, Ramos I, Cartar et al . Correlation of Doppler US tumor signals with neo vascular morphologic features, Radiology 1988; 166: 57-62.  Back to cited text no. 10    

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Correspondence Address:
Satish K Bhargava
E-3, GTB Hosp Campus, Dilshad Garden, Delhi - 110 095
India
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Source of Support: None, Conflict of Interest: None


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    Figures

[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]

    Tables

[Table - 1], [Table - 2], [Table - 3]



 

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