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Evaluation of adrenal disease by computed tomography
Compurerked 6 Pergamon
0363-8235/80/0801-016SS02.00/0
Tomography. Vol. 4. pp. 165 to 168 Press Ltd. 1980. Prmted in the U.S.A.
EVALUATION
OF ADRENAL DISEASE TOMOGRAPHY
BY COMPUTED
JOHN A. CURTIS, RICHARDE. BRENNANand ALFREDB. KURTZ The Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, U.S.A. (Received 20 November
1979; receivedfor
publication
2 January 1980)
Abstract-CT is the imaging modality of choice for screening possible adrenal pathology. It is non-invasive, safe, accurate and widely available. Excretory urography is not a good screening procedure. Ultrasound and radionuclide scanning are complementary procedures which often resolve equivocal or unsatisfactory CT studies. Angiography should be reserved for demonstration of vascular anatomy and/or cases unsolved by other techniques. Ultrasound Computed Tomography Adrenal venography Angiography Corm’s syndrome Adrenal mass Gushing’s syndrome Excretory urogram
Radionuclide scan Adrenal adenoma
INTRODUCTION Computed tomography (Cf’) is the method of choice for imaging the adrenal glands. Because it is non-invasive, safe accurate and widely available, CT is an ideal screening procedure. It should serve as the cornerstone of any scheme of diagnostic testing in the evaluation of adrenal abnormalities. Urotomography, radionuclide scanning, ultrasound and angiography are alternative imaging modalities which may supplement Cr, but which have major shortcomings. UROTOMOGRAPHY Urotomography (excretory urography with thin section tomography) is easy to perform, inexpensive, and widely available; however, there is a small risk of morbidity and mortality associated with the intravenous injection of contrast agents. More serious drawbacks are relatively poor resolution (only masses greater than 2.5 cm imaged), high rate of false negative examinations (about 25-x)%), and nonspecificity (high rate of false positive examinations from pseudotumors of bowel, spleen, liver, etc.) [1,2]. In addition, the normal adrenal glands are not reliably imaged RADIONUCLIDE
SCANNING
Radionuclide scanning with iodinated cholesterol derivatives is helpful when biochemical studies for suspected hormonally active disease of the adrenal cortex, e.g. Cushing and Conn syndromes, are positive. Under these circumstances, radionuclide scanning is very accurate. This examination has the unique advantage of being independent of structural change within the adrenal gland rendering very early diagnosis possible, even prior to enlargement or distortion of the gland [3]. This test can usually distinguish between adenoma and macronodular hyperplasia. However, lateralization is not reliable, resolution is poor, and medullary tumors as well as hormonally inactive cortical tumors are not imaged Furthermore, the radiation dose is high, the agents expensive and not widely available, and the study often prolonged (4-14 days) [2, 33. Some of these disadvantages may be resolved by newer radiopharmaceuticals now under investigation [l]. ANGIOGRAPHY Adrenal angiography and venous sampling are very accurate (approaching 100%). Masses as small as 1 cm in diameter may be visualized. Patient size and body habitus have little effect on this examination, and staging of tumors may be possible [4]. Pseudotumors may also be reliably evaluate as can regional vascular anatomy [S]. Venous sampling may permit functional analysis 165
166
JOHN A. CURTIS RICHARDE. BRENNANand ALFREDB. KIJRTZ
and lateralization even when the tumor is not demonstrated [4]. Aside from being a technically difficult, relatively expensive, and time consuming study,‘the chief disadvantage of angiography is that it is an invasive procedure associated with some patient discomfort and approximately SO,/, morbidity including adrenal infarction [l, 23. For these reasons, angiography is reserved for those cases which cannot be detected by other tests and for demonstrating the vascular anatomy prior to surgery. ULTRASOUND Ultrasound is ideally suited for studying thin patients. It is safe and has a resolution on the order of 2-3 cm. Since the normal adrenal gland may measure up to 3 cm in size, lesions smaller than this can only be detected if they have markedly different acoustic impedance than the normal adrenal gland. Adrenal cysts can be differentiated from tumor. The origin of large masses which may be difficult to assess by other imaging techniques, may often be resolved ultrasonographically by means of careful attention to vascular landmarks, multiple plane scanning and vector analysis [3]. Unfortunately, ultrasonic adrenal analysis is technically difficult to perform and interpret [l, 23. While good images are especially hard to obtain in obese patients, bowel gas in the left upper quadrant and ribs frequently interfere with the ultrasound examination of the left adrenal gland. COMPUTED
TOMOGRAPHY
(CT)
CT is ideally suited for evaluating adrenal pathology. It is fast, easy to perform and interpret, safe (administration of intravenous contrast agents is only occasionally necessary) and accurate. The normal adrenal glands are demonstrated in 90% of patients and masses as small as 1 cm can be reliably imaged [l]. Since the adjacent organs and retroperitoneum are imaged along with the adrenal glands, tumor dissemination may be evident. Pheochromocytoma and medulloblastoma may be multiple or occur in extra-adrenal sites in the abdomen. Adjacent Cf sections should be continued into the pelvis when searching for these malignancies. CT does have limitations: it is moderately expensive; the organ of origin of very large masses may be difficult to determine, especially if extensive invasion of adjacent structures has occurred and very young or very thin patients may be difficult to examine because of a paucity of retroperitoneal fat. Fortunately, ultrasound is complimentary in this regard and ideally suited to examine thin patients and large masses. Aside from myelolipoma, the CT scan cannot accurately predict the histology of adrenal tumors. However, this is not a severe handicap, since the clinical syndromes and biochemical studies are often specific. A more serious drawback is the occasional tumor with high lipid content which may have CT numbers similar to those of adrenal cysts [6]. In this case, ultrasound should differentiate cyst from solid adrenal tumor. CASE
REPORT
A 50 year old woman presented with uncontrolled hypertension. No renal cause for the hypertension was evident on excretory urography. Subsequent chemical studies were compatible with Conn’s syndrome. An ultrasound examination of the adrenal glands was negative. CT showed an unsuspected 4cm left adrenal mass (Fig. 1). Angiographic studies of the left adrenal gland were technically unsatisfactory and while a definite mass was not seen, venous sampling was abnormal on the left. A 3 x 4 x 5 cm left adrenal adenoma was surgically removed and the patient has been normotensive and off medication since surgery. This case illustrates the frequent difficulties which may arise during evaluation of adrenal masses. Ultrasound and urography were negative even in retrospect, and although angiography correctly lateralized the adrenal pathology, the left adrenal adenoma was not imaged. We have constructed a flow chart showing some common decision making pathways when evaluating possible adrenal abnormalities (Fig. 2). Detection of hyperplasia, cyst, hemorrhage and granulomatous disease of the adrenal gland as well as tumors have been well documented in the literature [l, 21. Our experience with CT in over 40 cases of adrenal pathology (including pheochromocytoma, adenoma, carcinoma, hyperplasia and metastatic disease) is in agreement with published reports showing an accuracy of over 90% with no false positive examinations.
Evaluation of adrenal disease by computed tomography
167
Fig. 1. (TT scan of the upper abdomen shows a solid 4 cm left adrenal tumor (TX spleen (S), aorta (A), upper pole of the left kidney (K), liver (L).
CUSHItGS,
CONN’S
PHSO2R@¶~Y9WfA
ADRENAL NASS ON PWIN uLTR&wvND,IVP,l?nz.
FILEI
I ~ChemicalStudiiQ
rigin
Surgery
J
/
\I
.
Y\
RADKINUCLIDE SCAN
x!2!2
+
20
HU
/
v
J
‘8 ULTRASOUND 0 ,I1 Tumor or /
J
CTI-10,
Cyst
Dx.: Adenome C~rCiIlOIlld Pheochromocytona Mets etc.
I' &
Surgery
Euuivocal (Both glands not visualized)
\ \ Dx.: Normal or
Hyperplasia
Fig. 2. An algorithm for the evaluation of adrenal pathology illustrates some of the common decisions regarding diagnostic testing. Positive (+ ), negative (-), equivocal + ), computed tomographic number in Hounsfield units ((TT No.), diagnosis (Dx), rule out (r/o).
168
JOHN A.
Cum& RICHARDE. BRENNANand ALFREDB. Kuttrr.
CONCLUSION In summary, CT is the imaging modality of choice for screening possible adrenal pathology. Ultrasound and radionuclide scanning are complimentary procedures which often resolve equivocal or unsatisfactory CT studies. Angiography should be reserved for demonstration of vascular anatomy and/or cases unsolved by other techniques. REFERENCES I. N. Karstaed, S. S. Sagel, R. J. Stanley, G. L. Melson and R. G. Levitt, Computed
2. 3. 4. 5. 6.
tomography of the adrenal gland Rudiology, 129, 723-730 (1978). M. Korobkin, E. A. White, H. Y. Kressei, A. A. Moss and J. P. Montagne, Computed tomography in the diagnosis of adrenal disease, Am. J. Roentg. 13x231-238 (1979). W. F. Sample and D. A. Sarti, Computed Tomography and gray scale ultrasonography of the adrenal gland: a comparative study, Rudiology 128, 337-383 (1978). H. Y. Yune, E. C. Klalte, C. E. Grim, M. H. Weinbcrger, J. P. Donohue, M. N. Yum and H. N. Wellman, Radiology in primary hyperaldosteronism, Am. J. Roentg. 127, 761-767 (1976). A. K. R. Rao, T. M. Silver, Normal pancreas and splenic variants simulating suprarenal and renal tumors, Am. J. Roenfg. 126, 530-537 (1976). E. G. Schaner, N. R. Dunnick, J. L. Doppman, C. A. Strott, J. R. Gill and N. Javadpour, Adrenal cortical tumors with low attenuation coefficients: a pitfall in computed tomography diagnosis, J. Comput. assist. Tomogr. 21, 1l-15 (1978). About the AII~IIO+DR Cuttns graduated with honors in Biology from Hamilton College in Clinton, New York. A graduate of the College of Physicians and Surgeons of Columbia University, he completed his internship at Mary Imogene Bassett Hospital in Cooperstown, New York and took his residency at Thomas Jefferson University Hospital where he was both Chief Resident and a Fellow of the American Cancer Society. Dr Curtis is currently an associate professor of diagnostic radiology at Thomas Jefferson University Hospital with special interest in Uroradiology and Computed Tomography. About the Author-RICHARD E. BRENNANreceived a B.S. degree in Chemistry from Allegheny College in 1968, and an M.D. degree from Jefferson Medical College in 1972. He completed a diagnostic radiology residency program at Thomas Jefferson University Hospital in 1976. He is currently associate professor of radiology at Thomas Jefferson University Hospital and co-chief of the section of Uroradiology. Recent research interests include the application of sequential CT scanning in evaluation of the renal handling of urographic contrast media. About the Au~&--DR KURTZ graduated from New York University with honors in Chemistry. After attending Stanford University Schqol of Medicine, he completed an Internship and first year Residency in Internal Medicine at Montefiore Hospital and Medical Center in New York. He took his Residency in Diagnostic Radiology at the same institution where he was Chief Resident during his last year and is Board Certified in Diagnostic Radiology. Dr Kurtz then studied for an additional year as a Fellow in Diagnostic Ultrasound and Computed Tomography at Thomas Jefferson University Hospital. He is currently an Assistant Professor in Diagnostic Radiology at Thomas Jefferson University Hospital with special interests in ultrasound and computed tomography of the body.
0363-8235/80/0801-016SS02.00/0
Tomography. Vol. 4. pp. 165 to 168 Press Ltd. 1980. Prmted in the U.S.A.
EVALUATION
OF ADRENAL DISEASE TOMOGRAPHY
BY COMPUTED
JOHN A. CURTIS, RICHARDE. BRENNANand ALFREDB. KURTZ The Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, U.S.A. (Received 20 November
1979; receivedfor
publication
2 January 1980)
Abstract-CT is the imaging modality of choice for screening possible adrenal pathology. It is non-invasive, safe, accurate and widely available. Excretory urography is not a good screening procedure. Ultrasound and radionuclide scanning are complementary procedures which often resolve equivocal or unsatisfactory CT studies. Angiography should be reserved for demonstration of vascular anatomy and/or cases unsolved by other techniques. Ultrasound Computed Tomography Adrenal venography Angiography Corm’s syndrome Adrenal mass Gushing’s syndrome Excretory urogram
Radionuclide scan Adrenal adenoma
INTRODUCTION Computed tomography (Cf’) is the method of choice for imaging the adrenal glands. Because it is non-invasive, safe accurate and widely available, CT is an ideal screening procedure. It should serve as the cornerstone of any scheme of diagnostic testing in the evaluation of adrenal abnormalities. Urotomography, radionuclide scanning, ultrasound and angiography are alternative imaging modalities which may supplement Cr, but which have major shortcomings. UROTOMOGRAPHY Urotomography (excretory urography with thin section tomography) is easy to perform, inexpensive, and widely available; however, there is a small risk of morbidity and mortality associated with the intravenous injection of contrast agents. More serious drawbacks are relatively poor resolution (only masses greater than 2.5 cm imaged), high rate of false negative examinations (about 25-x)%), and nonspecificity (high rate of false positive examinations from pseudotumors of bowel, spleen, liver, etc.) [1,2]. In addition, the normal adrenal glands are not reliably imaged RADIONUCLIDE
SCANNING
Radionuclide scanning with iodinated cholesterol derivatives is helpful when biochemical studies for suspected hormonally active disease of the adrenal cortex, e.g. Cushing and Conn syndromes, are positive. Under these circumstances, radionuclide scanning is very accurate. This examination has the unique advantage of being independent of structural change within the adrenal gland rendering very early diagnosis possible, even prior to enlargement or distortion of the gland [3]. This test can usually distinguish between adenoma and macronodular hyperplasia. However, lateralization is not reliable, resolution is poor, and medullary tumors as well as hormonally inactive cortical tumors are not imaged Furthermore, the radiation dose is high, the agents expensive and not widely available, and the study often prolonged (4-14 days) [2, 33. Some of these disadvantages may be resolved by newer radiopharmaceuticals now under investigation [l]. ANGIOGRAPHY Adrenal angiography and venous sampling are very accurate (approaching 100%). Masses as small as 1 cm in diameter may be visualized. Patient size and body habitus have little effect on this examination, and staging of tumors may be possible [4]. Pseudotumors may also be reliably evaluate as can regional vascular anatomy [S]. Venous sampling may permit functional analysis 165
166
JOHN A. CURTIS RICHARDE. BRENNANand ALFREDB. KIJRTZ
and lateralization even when the tumor is not demonstrated [4]. Aside from being a technically difficult, relatively expensive, and time consuming study,‘the chief disadvantage of angiography is that it is an invasive procedure associated with some patient discomfort and approximately SO,/, morbidity including adrenal infarction [l, 23. For these reasons, angiography is reserved for those cases which cannot be detected by other tests and for demonstrating the vascular anatomy prior to surgery. ULTRASOUND Ultrasound is ideally suited for studying thin patients. It is safe and has a resolution on the order of 2-3 cm. Since the normal adrenal gland may measure up to 3 cm in size, lesions smaller than this can only be detected if they have markedly different acoustic impedance than the normal adrenal gland. Adrenal cysts can be differentiated from tumor. The origin of large masses which may be difficult to assess by other imaging techniques, may often be resolved ultrasonographically by means of careful attention to vascular landmarks, multiple plane scanning and vector analysis [3]. Unfortunately, ultrasonic adrenal analysis is technically difficult to perform and interpret [l, 23. While good images are especially hard to obtain in obese patients, bowel gas in the left upper quadrant and ribs frequently interfere with the ultrasound examination of the left adrenal gland. COMPUTED
TOMOGRAPHY
(CT)
CT is ideally suited for evaluating adrenal pathology. It is fast, easy to perform and interpret, safe (administration of intravenous contrast agents is only occasionally necessary) and accurate. The normal adrenal glands are demonstrated in 90% of patients and masses as small as 1 cm can be reliably imaged [l]. Since the adjacent organs and retroperitoneum are imaged along with the adrenal glands, tumor dissemination may be evident. Pheochromocytoma and medulloblastoma may be multiple or occur in extra-adrenal sites in the abdomen. Adjacent Cf sections should be continued into the pelvis when searching for these malignancies. CT does have limitations: it is moderately expensive; the organ of origin of very large masses may be difficult to determine, especially if extensive invasion of adjacent structures has occurred and very young or very thin patients may be difficult to examine because of a paucity of retroperitoneal fat. Fortunately, ultrasound is complimentary in this regard and ideally suited to examine thin patients and large masses. Aside from myelolipoma, the CT scan cannot accurately predict the histology of adrenal tumors. However, this is not a severe handicap, since the clinical syndromes and biochemical studies are often specific. A more serious drawback is the occasional tumor with high lipid content which may have CT numbers similar to those of adrenal cysts [6]. In this case, ultrasound should differentiate cyst from solid adrenal tumor. CASE
REPORT
A 50 year old woman presented with uncontrolled hypertension. No renal cause for the hypertension was evident on excretory urography. Subsequent chemical studies were compatible with Conn’s syndrome. An ultrasound examination of the adrenal glands was negative. CT showed an unsuspected 4cm left adrenal mass (Fig. 1). Angiographic studies of the left adrenal gland were technically unsatisfactory and while a definite mass was not seen, venous sampling was abnormal on the left. A 3 x 4 x 5 cm left adrenal adenoma was surgically removed and the patient has been normotensive and off medication since surgery. This case illustrates the frequent difficulties which may arise during evaluation of adrenal masses. Ultrasound and urography were negative even in retrospect, and although angiography correctly lateralized the adrenal pathology, the left adrenal adenoma was not imaged. We have constructed a flow chart showing some common decision making pathways when evaluating possible adrenal abnormalities (Fig. 2). Detection of hyperplasia, cyst, hemorrhage and granulomatous disease of the adrenal gland as well as tumors have been well documented in the literature [l, 21. Our experience with CT in over 40 cases of adrenal pathology (including pheochromocytoma, adenoma, carcinoma, hyperplasia and metastatic disease) is in agreement with published reports showing an accuracy of over 90% with no false positive examinations.
Evaluation of adrenal disease by computed tomography
167
Fig. 1. (TT scan of the upper abdomen shows a solid 4 cm left adrenal tumor (TX spleen (S), aorta (A), upper pole of the left kidney (K), liver (L).
CUSHItGS,
CONN’S
PHSO2R@¶~Y9WfA
ADRENAL NASS ON PWIN uLTR&wvND,IVP,l?nz.
FILEI
I ~ChemicalStudiiQ
rigin
Surgery
J
/
\I
.
Y\
RADKINUCLIDE SCAN
x!2!2
+
20
HU
/
v
J
‘8 ULTRASOUND 0 ,I1 Tumor or /
J
CTI-10,
Cyst
Dx.: Adenome C~rCiIlOIlld Pheochromocytona Mets etc.
I' &
Surgery
Euuivocal (Both glands not visualized)
\ \ Dx.: Normal or
Hyperplasia
Fig. 2. An algorithm for the evaluation of adrenal pathology illustrates some of the common decisions regarding diagnostic testing. Positive (+ ), negative (-), equivocal + ), computed tomographic number in Hounsfield units ((TT No.), diagnosis (Dx), rule out (r/o).
168
JOHN A.
Cum& RICHARDE. BRENNANand ALFREDB. Kuttrr.
CONCLUSION In summary, CT is the imaging modality of choice for screening possible adrenal pathology. Ultrasound and radionuclide scanning are complimentary procedures which often resolve equivocal or unsatisfactory CT studies. Angiography should be reserved for demonstration of vascular anatomy and/or cases unsolved by other techniques. REFERENCES I. N. Karstaed, S. S. Sagel, R. J. Stanley, G. L. Melson and R. G. Levitt, Computed
2. 3. 4. 5. 6.
tomography of the adrenal gland Rudiology, 129, 723-730 (1978). M. Korobkin, E. A. White, H. Y. Kressei, A. A. Moss and J. P. Montagne, Computed tomography in the diagnosis of adrenal disease, Am. J. Roentg. 13x231-238 (1979). W. F. Sample and D. A. Sarti, Computed Tomography and gray scale ultrasonography of the adrenal gland: a comparative study, Rudiology 128, 337-383 (1978). H. Y. Yune, E. C. Klalte, C. E. Grim, M. H. Weinbcrger, J. P. Donohue, M. N. Yum and H. N. Wellman, Radiology in primary hyperaldosteronism, Am. J. Roentg. 127, 761-767 (1976). A. K. R. Rao, T. M. Silver, Normal pancreas and splenic variants simulating suprarenal and renal tumors, Am. J. Roenfg. 126, 530-537 (1976). E. G. Schaner, N. R. Dunnick, J. L. Doppman, C. A. Strott, J. R. Gill and N. Javadpour, Adrenal cortical tumors with low attenuation coefficients: a pitfall in computed tomography diagnosis, J. Comput. assist. Tomogr. 21, 1l-15 (1978). About the AII~IIO+DR Cuttns graduated with honors in Biology from Hamilton College in Clinton, New York. A graduate of the College of Physicians and Surgeons of Columbia University, he completed his internship at Mary Imogene Bassett Hospital in Cooperstown, New York and took his residency at Thomas Jefferson University Hospital where he was both Chief Resident and a Fellow of the American Cancer Society. Dr Curtis is currently an associate professor of diagnostic radiology at Thomas Jefferson University Hospital with special interest in Uroradiology and Computed Tomography. About the Author-RICHARD E. BRENNANreceived a B.S. degree in Chemistry from Allegheny College in 1968, and an M.D. degree from Jefferson Medical College in 1972. He completed a diagnostic radiology residency program at Thomas Jefferson University Hospital in 1976. He is currently associate professor of radiology at Thomas Jefferson University Hospital and co-chief of the section of Uroradiology. Recent research interests include the application of sequential CT scanning in evaluation of the renal handling of urographic contrast media. About the Au~&--DR KURTZ graduated from New York University with honors in Chemistry. After attending Stanford University Schqol of Medicine, he completed an Internship and first year Residency in Internal Medicine at Montefiore Hospital and Medical Center in New York. He took his Residency in Diagnostic Radiology at the same institution where he was Chief Resident during his last year and is Board Certified in Diagnostic Radiology. Dr Kurtz then studied for an additional year as a Fellow in Diagnostic Ultrasound and Computed Tomography at Thomas Jefferson University Hospital. He is currently an Assistant Professor in Diagnostic Radiology at Thomas Jefferson University Hospital with special interests in ultrasound and computed tomography of the body.