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Evaluation of thyroid masses by magnetic resonance imaging
POSTER ABSTRACTS:
tTRA!GES IN CORRXAL IWPERATURE IN
-IATFD
GENERAL
YITSI HIGH-FIELD
(I.5
=A)
95
MAGNETIC
RESONANCE IMAGING: tPPEBIENCE
118 PATIENTS.
Frank G. Shellock, Ph.D. and John 8. Crues, M.D. Division of Cardiology, Departmentof Medicine and Division of magnetic Resonance Imaging, Departmentof Diagnostic Radiology. Cedars-SinaiMedical Center and UCLA School of Medicine, Los Angeles, CA 90048 Radiofrequency(RF) pulses are required for magnetic resonance (MR) proton imaging and the frequency of these pulses are directly proportional to the static magnetic field strength. Exposure to RF power is known to increase tissue temperaturesand may be harmful to thermally sensitive tissues. The eye is particularly susceptible to thermal damage, therefore, the purpose of this investigationwas to determine the temperature effects of high-field HR imaging on cornea1 temperature. A 1.5 Tesla superconductingmagnet was used in this investigation(Signa MR System, General Electric Company, Milwaukee, WI). A total of 118 patients ware studied: 52 males, 66 females, average age 44 years, range lo-87 years old. Cornea1 temperature3were measured with a non-invasiveinfrared thermometer (Meditherm,Everest Interscience,Tustin, CA) with a spot size setting of 5 mm (7). Ambient conditions were room temperature 20-24 C and relative humidity of 40-50%. Temperaturemeasurementswsre obtained immediatelybefore and after MR imaging. he MR scans were obtained for diagnostic purposes, using cpnventional RF pulse sequences. The estimated average whole body specific absorption rate ranged from 0.06 W/kg to 1.81 W/kg (U.S. FDA advises an analysis of health effects if 8F deposition 6s greater than an SAR of 0.4 W/kg). The average cornea1 temperature increased from 32.7+0.7 C to 32.1+0.6 C (p
Shellock FG, Riedinger MS, Adler L: Measurement of cornea1 and supra-orbitaltemperaturesusing a portable infrared thermometer. Clinical Research 32:32A, 1984. Elder JA: Special senses. In, Biological Effects of RadiofrequencyRadiation. EPA-600/8-83-026F, pp. 5-64 to 5-69, 1964.
EVALUATION S.A.
Kroop”,
OF THYROID D.
MASSES BY MAGNETIC RESONANCE IMAGING
Margouleff**,
I.
Zanzi*+,
M.
Susina**,
M.A.
Goldman;? and
Medicine”* and Pathology*“*, From the Departments of Radiology*, New York and the Departments of Radiology, Medicine Manhasset, Medical College, New York, New York
H.L.
North Shore and Pathology,
Stein;: University Cornell
Hospital University
,
Twenty patients with palpable thyroid masses were prospectively evaluated by nuclear medicine, high All MRI studies were resolution real-time ultrasound and magnetic resonance imaging (MRI) techniques. performed with a 0.6 Tesla superconducting magnet utilizing whole body or surface coils and TT and T2 transverse and sagittal planes. weighted spin echo and inversion recovery pulse sequences in coronal, Diagnoses were established by surgery (n=18) or by radiologic/clinical correlation and follow-up of at There were 6 cases of solitary adenoma, least 12 months (n=2). 8 cases of multinodular adenomatous 2 cases of follicular carcinoma and 1 case of epidermoid goiter, 3 cases of papillary carcinoma, Solitary adenomas were round somewhat inhomogeneous lesions with MRI detected all lesions. carcinoma. relatively smooth sharply defined margins demonstrating variable signal intensity on T1 weighted images Adenomatous goiters were characterized by gland and high signal intensity on T2 weighted images. and by multiple nodules of relatively low signal intensity on TT weighted enlargement, heterogeneity, All malignancies were lobulated heterogeneous images and high signal intensity on T2 weighted images. masses of relatively low signal intensity on TT weighted images and high signal intensity on T2 weighted MRI was useful in depicting lesion margin, lesion extent, tissue heterogeneity, cystic and images. invasion or compression of adjacent anatomic structures hemorrhagic regions, cervical lymphadenopathy, Qualitative assessment of MRI signal intensity was not and additional non-palpable thyroid nodules. lesion specific with regard to pathologic diagnosis.
tTRA!GES IN CORRXAL IWPERATURE IN
-IATFD
GENERAL
YITSI HIGH-FIELD
(I.5
=A)
95
MAGNETIC
RESONANCE IMAGING: tPPEBIENCE
118 PATIENTS.
Frank G. Shellock, Ph.D. and John 8. Crues, M.D. Division of Cardiology, Departmentof Medicine and Division of magnetic Resonance Imaging, Departmentof Diagnostic Radiology. Cedars-SinaiMedical Center and UCLA School of Medicine, Los Angeles, CA 90048 Radiofrequency(RF) pulses are required for magnetic resonance (MR) proton imaging and the frequency of these pulses are directly proportional to the static magnetic field strength. Exposure to RF power is known to increase tissue temperaturesand may be harmful to thermally sensitive tissues. The eye is particularly susceptible to thermal damage, therefore, the purpose of this investigationwas to determine the temperature effects of high-field HR imaging on cornea1 temperature. A 1.5 Tesla superconductingmagnet was used in this investigation(Signa MR System, General Electric Company, Milwaukee, WI). A total of 118 patients ware studied: 52 males, 66 females, average age 44 years, range lo-87 years old. Cornea1 temperature3were measured with a non-invasiveinfrared thermometer (Meditherm,Everest Interscience,Tustin, CA) with a spot size setting of 5 mm (7). Ambient conditions were room temperature 20-24 C and relative humidity of 40-50%. Temperaturemeasurementswsre obtained immediatelybefore and after MR imaging. he MR scans were obtained for diagnostic purposes, using cpnventional RF pulse sequences. The estimated average whole body specific absorption rate ranged from 0.06 W/kg to 1.81 W/kg (U.S. FDA advises an analysis of health effects if 8F deposition 6s greater than an SAR of 0.4 W/kg). The average cornea1 temperature increased from 32.7+0.7 C to 32.1+0.6 C (p
Shellock FG, Riedinger MS, Adler L: Measurement of cornea1 and supra-orbitaltemperaturesusing a portable infrared thermometer. Clinical Research 32:32A, 1984. Elder JA: Special senses. In, Biological Effects of RadiofrequencyRadiation. EPA-600/8-83-026F, pp. 5-64 to 5-69, 1964.
EVALUATION S.A.
Kroop”,
OF THYROID D.
MASSES BY MAGNETIC RESONANCE IMAGING
Margouleff**,
I.
Zanzi*+,
M.
Susina**,
M.A.
Goldman;? and
Medicine”* and Pathology*“*, From the Departments of Radiology*, New York and the Departments of Radiology, Medicine Manhasset, Medical College, New York, New York
H.L.
North Shore and Pathology,
Stein;: University Cornell
Hospital University
,
Twenty patients with palpable thyroid masses were prospectively evaluated by nuclear medicine, high All MRI studies were resolution real-time ultrasound and magnetic resonance imaging (MRI) techniques. performed with a 0.6 Tesla superconducting magnet utilizing whole body or surface coils and TT and T2 transverse and sagittal planes. weighted spin echo and inversion recovery pulse sequences in coronal, Diagnoses were established by surgery (n=18) or by radiologic/clinical correlation and follow-up of at There were 6 cases of solitary adenoma, least 12 months (n=2). 8 cases of multinodular adenomatous 2 cases of follicular carcinoma and 1 case of epidermoid goiter, 3 cases of papillary carcinoma, Solitary adenomas were round somewhat inhomogeneous lesions with MRI detected all lesions. carcinoma. relatively smooth sharply defined margins demonstrating variable signal intensity on T1 weighted images Adenomatous goiters were characterized by gland and high signal intensity on T2 weighted images. and by multiple nodules of relatively low signal intensity on TT weighted enlargement, heterogeneity, All malignancies were lobulated heterogeneous images and high signal intensity on T2 weighted images. masses of relatively low signal intensity on TT weighted images and high signal intensity on T2 weighted MRI was useful in depicting lesion margin, lesion extent, tissue heterogeneity, cystic and images. invasion or compression of adjacent anatomic structures hemorrhagic regions, cervical lymphadenopathy, Qualitative assessment of MRI signal intensity was not and additional non-palpable thyroid nodules. lesion specific with regard to pathologic diagnosis.