Intraocular tumors the value of spectral and color Doppler sonography

ELSEVIER

INTRAOCULAR TUMORS THE VALUE OF SPECTRAL AND COLOR DOPPLER SONOGRAPHY HAKAN &DEhdR,

MD, CEM

YUCEL,

MD,

CUNEYT AYTEKIN, MD, BARAN ONAL, MD, ANDAY ATAMAN, MD, YELDA ijZSUNAR, AND SEDAT ISIK, MD

We evaluated the efficacy of spectral and color Doppler sonography as a screening procedure for intraocular tumors. Thirty patients who had intraocular tumors were included in the study. Abnormal Doppler shifts were demonstrated 19 of 20 patients with choroidal malignant melanomas, especially at the base of the tumors. The average maximum systolic blood flow velocity in the vessels of these tumors was 2 7 2 6.8 cm/see (14 to 28 cm/set). In one of the choroidal metastasis, blood vessels were seen around the lesion with a 14-cm/see maximum peak systolic velocity. Intratumoral vascularity could not be demonstrated in the other tumors. Spectral and color Doppler imaging is a relatively new and promising modality in the management of intraocular tumors and may help to provide a more precise preoperative histological diagnosis noninvasively; however, longterm follow-up is needed. 0 Elsevier Science Inc., 1997 KEY WORDS: Orbital

neoplasms,

Sonography,

diagnosis; color

Choroidal

tumors,

diagnosis;

MD,

orders since the early 1960s (1). Sonography is especially useful if the vitreous chamber is difficult to examine. Spectral and color Doppler ultrasound, which detects changes in the frequency of sound reflected from flowing blood, allowing estimation of flow velocity, is widely used in the evaluation of orbital vessels. As the sensitivity of detecting Doppler shifts is not limited by the resolution of the grayscale image, Doppler shifts in very small vessels can be detected, depicting the course of the vessels (z-4). The possibilities of effecting a more accurate tissue diagnosis in intraocular tumors are fully described in the literature; however, in many cases doubt can remain as to the nature of the lesions (5,6). Detecting vascularity within an intraocular tumor is helpful in the sonographic diagnosis (7-9). With classic methods it is difficult to ascertain the existence of vascularity and it is impossible to evaluate speed and direction of flow (10). The purpose of our study was to determine the value of spectral and color Doppler sonography for the evaluation of intraocular tumors.

Doppler

MATERIALS INTRODUCTION Real-time A-mode and B-mode sonography has been used for the diagnostic evaluation of ophthalmic disFrom the Department of Radiology, School of Medicine, Gazi University, BeSevler, Ankara, Ttirkiye. Address reprint requests to: Hakan dzdemir, MD, Department of Radiology, School of Medicine, Gazi University, Bqevler 06510, Ankara, Tiirkiye. Received February 28, 1995; accepted September 6, 1995. CLINICAL IMAGING 1997;21:77-81 0 Elsevier Science Inc., 1997 655 Avenue of the Americas, New York, NY 10010

AND METHODS

Spectral and color Doppler ultrasound examinations were carried out in 30 patients (14 women, 16 men), aged 1 to 62 years (mean, 44 years) who were diagnosed to have intraocular tumors between January 1993 and September 1994. Twenty patients had choroidal melanomas; one, choroidal hemangioma; two, choroidal metastasis; three, retinoblastoma; one, optic nerve glioma; and three, benign lacrimal gland tumors. The diagnosis of intraocular tumors was made

0899-7071/97/$17.00 SSDI 0899-7071(95)00094-l

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OZDEM~RETAL.

in all patients by clinical examination, fluorescein angiography, and sonography and was confirmed in all patients on the basis of histopathological diagnosis (surgical or biopsy specimens) or clinical followup on medical treatment. All examinations were done by one radiologist experienced in ultrasound scanning. The patients were examined in the supine position with both eyes closed; sterile coupling gel was directly placed on the closed eyelid. Patients were asked to keep their eyes immobile as much as possible, looking directly ahead; occasionally, medial or lateral gaze was requested to increase the visibility of ciliary vessels. Care was taken not to apply pressure on the eye, to avoid artifacts. Vascular structures were demonstrated in axial and oblique scans. The axial scans were used to obtain an overall view of the orbita and identify the precise direction of the orbital vessels. Oblique scans were obtained parallel to the long axis of each vessel for optimal visualization and accurate blood flow measurements. The average examination time was 10 to 15 minutes. Examinations were performed by using a 7.5MHz, linear phased-array transducer (Toshiba SSA270A, Tokyo, Japan). The system enables detection of amplitude, phase, and frequency shift, resulting in a real-time gray-scale/color-flow image. Color assignment depends on the direction of blood flow and is operator selectable. When the eye and orbit are examined through the eyelids, the ultrasound beam is almost parallel to the orbital vessels; thus due to the flow direction, arterial flow is shown in red. Excessive “color noise” due to involuntary ocular motion precluded the use of maximum-sensitivity Doppler receiver gain for the real-time color-flow display. Color and pulsed Doppler examinations were performed with medium- and low-flow settings (high Doppler gain, low PRF, and high sensitivity of signal FFT). To obtain Doppler spectra, a fixed sample volume of approximately 0.2 X 0.2 mm within a vessel was chosen by the guidance of color-flow image. Spectral sampling throughout the vessels in different planes was performed and the maximum Doppler shift was recorded. The scans were digitally recorded on videotape and later reviewed by the help of cineloop and hame-by-frame analysis of selected segments. RESULTS Thirty patients with intraocular mass lesions were first examined with gray-scale sonography and then with spectral and color Doppler sonography. Doppler signals were detected within 20 (66.6%) of the lesions.

CLINICAL IMAGING VOL. 21, NO. 2

FIGURE 1. Color Doppler sonogram of a choroidal mel-

anoma. Prominent vessels are seen at the base of the tumor (tu).

The size of the choroidal melanomas varied from 48 to 2500 mm3 and their gray-scale appearances showed a wide variety. Most melanomas had relatively homogeneous echogenicity (15/20), three tumors showed less echogenicity, and two hypoechoic tumors had cystic portions representing necrotic or hemorrhagic areas. Nineteen (95%) of the 20 patients with untreated choroidal melanomas showed abnormal Doppler signals within and especially at the base of the lesions (Figure 1). No intrinsic vascularity could be detected in one small choroidal melanoma (150 mm3). The average maximum systolic blood flow velocity in the vessels of these tumors was 17 2 6.8 cm/set (14 to 28 cm/set) (Figure 2A and 2B). Neither peak nor time average velocities showed a statistically significant correlation with tumor volume. Gray-scale sonography of the two choroidal metastases showed a heterogeneous hypoechoic appearance. In one of the choroidal metastasis from breast cancer, blood vessels were seen around and within the lesion (Figure 3) with a 14cm/set maximum peak systolic velocity and in the other one no blood vessels were demonstrated. Intratumoral vascularity could not be demonstrated in one choroidal hemangioma, which had a echogenic sonographic appearance. In three patients with retinoblastoma we demonstrated relatively big, heterogeneous solid mass lesions with some calcifications inside the tumor (Figure 4). Intratumoral vascularity could not be demonstrated in these lesions. Gray-scale sonography demonstrated an intraconal hypoechoic solid mass lesion in one patient with optic nerve glioma and extraconal cystic lesions in three patients with benign lacrimal gland tumors. No Doppler signals could be detected in these lesions.

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FIGURE 2. (A) Color Doppler imaging of a small choroidal melanoma. Tumor vessels appear red (small arrow). (B) Spectral and color Doppler sonogram of the same patient. Spectral form shows a high maximum systolic shift, which is characteristic for malignant tumors. DISCUSSION Orbital sonography has been a mainstay in the evaluation of suspected orbital disease. Both A-mode and B-mode methods are used in the routine examinations, and Doppler imaging is usually reserved for selected patients. Recent studies showed that spectral and color Doppler sonography of the orbit is a reliable technique that gives information on the position, course, direction, and the approximate flow velocity of the principal vessels, making it possible to adjust the sample volume accurately for spectral Doppler examination (2-4). In the present study, spectral and color Doppler sonography was performed to evaluate intraocular

FIGURE 3. Choroidal metastasis in a patient previously operated on for breast carcinoma. The large intraocular solid mass is seen with a vessel inside it (appears red).

tumors. Although most intraocular tumors can be diagnosed clinically, adjunctive imaging techniques are used to confirm and document the diagnosis (10, 11).Effective vasculature is essential for all tumor growth and is formed by newly sprouted ingrowing vessels and by incorporation of existing host vessels into the tumor mass (9). Fluorescein angiography and A-mode ultrasonography are the two most important conventional methods used to evaluate this tumor vasculature (12). Fluorescein angiography depends on clear refractive media and may not display tumor vessels. Superficial, prominently engorged vessels in tumors that have broken through Bruch’s membrane are sometimes seen. Retinal pigment epithelial staining can sometimes cause hyperfluorescence rather than dye leakage from tumor vasculature. Hyperfluroescence is often not present in smaller tumors (13, 14). Other imaging techniques, such as computed tomography and magnetic resonance imaging, may be useful in selected patients; however, these techniques are more time-consuming and expensive and are less widely available (15). A-mode sonography does not require clear refractive media and is very useful in tissue characterization, but it gives no information about vascular topography (16). B-mode sonography is excellent for evaluating intravitreous tumor size and localization. However, it is not useful in the differential diagnosis of benign and malignant lesions (15). Doppler techniques are widely used in the study of tumor vasculature throughout the human body (17-2 1). It requires neither clear refractive media nor intravenous injections. It causes minimal discomfort and takes 10 to 15 minutes to perform. The high sen-

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sitivity in detecting even minimal flow is necessary to allow detection of fine tumor vascularity. Because the angle of incidence is unknown in Doppler ultrasonography, the numerical values produced are not absolutely reliable. Presence or absence of duplex Doppler shift is clinically more reliable than are numerical values. Color Doppler scanning obviates this problem by allowing direct observation of the angle of incidence (22). Preliminary reports on spectral and color Doppler diagnosis of orbital tumors indicate that it is possible to detect Doppler signals in a majority of choroidal melanomas (12, 22). Guthoff et al. (22) reported that Doppler shifts were detected in all but one of the choroidal melanomas they evaluated and the average systolic blood flow velocity in the vessels of these tumors was 18.8 + 7.6 cm/set. They did not detect any Doppler shift in the tumor that was small and located in the outer periphery including the ciliary body (22). The present study demonstrated that it can be possible to detect Doppler signals in the majority of choroidal melanomas. The average maximum peak systolic blood flow velocities in choroidal melanomas (17 ? 6.8 cm/set (14 to 28 cm/set)) were slower than in normal ophthalmic arteries (31.6 k 9.0 cm/set, according to Guthoff et al. (1991)) but faster than in normal central retinal arteries (9.5 k 3.1 cm/set). The values for the average maximum peak systolic blood flow velocities in choroidal melanomas that we obtained were not different from those found in similar previous studies and our findings agreed with the findings of relevant previous studies (12, 22). Lesions that can simulate choroidal melanomas,

such as subretinal hemorrhages and age-related maculopathy with neovascular membrane, usually do not have a distinctive blood supply. Therefore, it can be possible to differentiate melanomas from tumorlike lesions on the basis of the existence of Doppler flow (9, 23). Jain et al. (24) reported that although choroidal metastases may not be distinguishable from choroidal melanomas with both gray-scale and duplex Doppler findings, blood vessels can be seen more frequently around the tumors than at the base of the lesions in choroidal metastases. However, we demonstrated blood flow within the choroidal metastasis from breast carcinoma, and it has not been possible to find statistically analysis and comparison with the melanoma group in the relevant literature because of the relatively small number of nonmelanoma neoplasms available for spectral and color Doppler sonography (9). Additionally, rather than tumoral subtype distinction, the primary benefit of color Doppler imaging is to distinguish neoplasms from pathologies that can stimulate tumor. We were not able to demonstrate any Doppler shifts in choroidal hemangioma; however, it is possible to demonstrate large pools of flow and a speckled or spot pattern at the tumor base (9, 24). We also did not detect intratumoral vascularity in the other intraocular tumors. In conclusion, spectral and color Doppler sonography of intraocular tumors is still in the early stages of development and there is still a need for further studies. However, we believe that our initial experience and results are encouraging, and to date, no other technique gives us quantitative information such as blood flow within the lesions. Furthermore, it is a noninvasive, easy-to-perform, and well-tolerated examination that may help to narrow the differential diagnosis of orbital mass lesions,

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