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Diagnosis of the empty sella with intrathecal metrizamide computed tomography
SURVEY OF OPHTHALMOLOGY VOLUME 28 NUMBER 1 JULY-AUGUST 1983 l
l
IMAGES JONATHAN
D. WIRTSCHAFTER,
EDITOR
Diagnosis of the Empty Sella With Intrathecal Metrizamide Computed Tomography MICHAEL J. PRICE, M.D.,’ JAMES J. CORBETT, H. STANLEY THOMPSON, M.D.’
Departments of’
M.D.,* AND
Ophthalmology and 2 Neurology, lJniversit_y of Iowa, Iowa City, Iowa
Abstract. The empty sella syndrome can be diagnosed with high resolution computed tomog-
raphy. The addition of intrathecal metrizamide defines the degree of extension of the subarachnoid space into the sella turcica, demonstrates the relationship of surrounding structures, and differentiates the empty sella from other isodense or hypodense intrasellar lesions. Photographs from a case of primary empty sella demonstrate the details of anatomy seen with metrizamide computed tomography combined with sagittal reconstruction. (Surv Opbthalmol 28:42-44, 1983)
Key words. intrathecal
computerized tomography empty sella metrizamide computed tomography sagittal CT reconstruction l
l
l
B
demonstrates the degree of herniation into the sella turcica and particularly the relationships of surThe following case illusrounding structures. 1,4,6,7,11 trates the superiority of intrathecal metrizamide and sagittal multiplanar reconstruction CT views in the evaluation of empty sella syndrome.
usch in 1951 first employed the term “empty sella” to describe a condition in which the diaphragma sellae was reduced to a small rim of peripheral tissue and the pituitary gland was flattened along the sellar floor.3 Clinically, the diagnosis of this condition rested on the demonstration of an enlarged sella on skull x-rays and air which filled or partially filled the pituitary fossa during pneumoencephalography. ‘,‘OComputed tomography has replaced air contrast studies in the diagnosis of empty sella.l*gJo However, conventional computed tomography, even with our present three millimeter sections, cannot differentiate an empty sella from a necrotic pituitary adenoma or other low density intrasellar lesions, especially if the infundibulum is not well visualized.4,8 The empty sella is not truly “empty,” but consists of an extension of the subarachnoid space through a defective diaphragma sellae. Contrast material (metrizamide) injected within the subarachnoid space more convincingly
Case Report A 38-year-old obese woman was seen in consultation after she developed transient obscurations of vision. Her visual acuities were 20/20 (6/6) OU and she had bilateral papilledema. Conventional axial CT scan revealed an area isodense to cerebrospinal fluid (CSF) partially filling the sella turcica. The relatively hypodense area was found within the sella using sagittal reconstruction (Fig. 1). Metrizamide was introduced into the subarachnoid space and sagittal reconstruction of the computed axial views was repeated.5 The subarachnoid space extended through the presumably defective diaphragma sel42
EMPTY
SELLA
Key to labels: A = Hypodense area within the sella turcica; B = Dorsum sellae; E = Tuberculum sellae; F = Posterior clinoid; G = Planum sphenoidale; H = Basilar artery; I = Metrizamide-containing subarachnoid space within the sella turcica; J = Pituitary gland; K = Pons; L = Mamillary bodies; M = Infundibulum; N = Chiasm
Fig. 1. Sagittal reconstruction with intravascular contrast (conray). The hypodense area (A) extends through most of the sella turcica. The position of the pituitary gland cannot be distinguished as the infundibulum is not visualized. The chiasm is not seen. Note that the basilar artery is filled with contrast (H).
Fig. 2. Sagittal reconstruction with intrathecal water soluble contrast (metrizamide). The degree of extension of subarachnoid space into the sella turcica is outlined by metrizamide (I). The pituitary gland (J) is compressed along the floor and walls of the sella turcica and the negative shadow corresponding to the infundibulum is well visualized (M). Within the suprasellar cistern is the negative shadow ofthe optic chiasm (N). Note the basilar artery (H) is seen as a negative shadow outlined by contrast in the prepontine cistern (compare with Fig. 1).
lae, well delineated by metrizamide (Fig. 2). The pituitary gland was compressed against the floor and dorsum sellae. The chiasm was outlined by metrizamide and did not appear to be dragged into the “empty” sella. Cerebrospinal fluid pressure was 320 mm of water. The diagnosis was consistent with pseudotumor cerebri associated with empty sella. The empty sella needs to be clearly separated from other causes of an enlarged sella. The diagnosis of empty sella can be suggested with computed
tomography using reconstruction views without pneumoencephalography. Injection of metrizamide by lumbar puncture permits precise visualization of the pericerebral cisterns and the structures in and around the sella turcica. Metrizamide contrast studies help define the intracranial anatomy, differentiate spaces from masses, and can demarcate the extent of mass lesions more clearly than was possible with earlier studies. Indications for the use of metrizamide con-
44
Surv Ophthdmol
28 (1) July-August
1983
trast in the empty sella include a need to define the location of the chiasm in the case of visual 10s~;~ differentiation of the truly empty sella from low density intrasellar lesions such as a lucent chromophobe adenoma, craniopharyngioma, or necrotic tumor (especially if the infundibulum is not well visualized); and delineation of the lateral, rostra& caudal, and superior extent of intrasellar mass lesions, especially those which are hypodense or isodense to the CSF.@
References Bajraktari X, Bergstrom M, Brismar K, et al: Diagnosis of intrasellar cisternal herniation (empty sella) by computer assisted tomography. J Cornput Assist 7’omogr 1:105-l 16, 1977 Bursztyn EM, Lavyne MH, Aisen M: Empty sella syndrome with intrasellar herniation of the optic chiasm. Am JNeuroradiol 4:167-168, 1983 Busch W: Die Morphologie der Sella Turcica und ihre Beziehungen zur Hypophyse. Virchows Arch Pathol Anat 320:437-458, 1951 Chui M, Pate1 HM: Computed tomography of sellar and parasellar lesions: Indications for metrizamide cisternography. J Can
PRICE
ET AL
Assoc Radio1 33:84-88, 1982 5. Di Chiro G, Schellinger D: Computed tomography of spinal cord after lumbar intrathecal introduction of metrizamide (computer assisted myelography). Radiology 220: 101-104, 1976 6. Ghoshhajra K: High-resolution metrizamide CT cisternography in sellar and suprasellar abnormalities. J Neurosurg 54232-239, 1981 7. Gross CE, Binet EF, Esguerra JV: Met&amide cisternography in the evaluation of pituitary adenomas and the empty selia syndrome. J Neurosurg 50:472-476, 1979 8. Guibert-Tranier F, Elie G, Guibert JL, Piton J, CaillC JM: The empty sella: CT diagnosis. J Neuroradiol 7: 105119, 1980 9. Ketonen L, Kuuliala I: Diagnosis of primary empty sella syndrome by computed tomography. Ann Clin Res II: 125-128,1979 10. Rozario R, Hammerschlag SB, Post KD, et al: Diagnosis of empty sella with CT scan. Neuroradiology 13:85-88, 1977 11. Young WF, Ospina LF, Wesolowski D, Towma A: The primary empty sella syndrome: Diagnosis with metrizamide cisternography. JAMA 246:2611-2612, 1981
This investigation was supported in part by Foundation for the Prevention of Blindness (Dr. Reprint requests should be addressed to: James Department of Neurology, University of Iowa, 52242.
the E. A. Baker Price). J. Corbett, M.D., Iowa City, Iowa
l
IMAGES JONATHAN
D. WIRTSCHAFTER,
EDITOR
Diagnosis of the Empty Sella With Intrathecal Metrizamide Computed Tomography MICHAEL J. PRICE, M.D.,’ JAMES J. CORBETT, H. STANLEY THOMPSON, M.D.’
Departments of’
M.D.,* AND
Ophthalmology and 2 Neurology, lJniversit_y of Iowa, Iowa City, Iowa
Abstract. The empty sella syndrome can be diagnosed with high resolution computed tomog-
raphy. The addition of intrathecal metrizamide defines the degree of extension of the subarachnoid space into the sella turcica, demonstrates the relationship of surrounding structures, and differentiates the empty sella from other isodense or hypodense intrasellar lesions. Photographs from a case of primary empty sella demonstrate the details of anatomy seen with metrizamide computed tomography combined with sagittal reconstruction. (Surv Opbthalmol 28:42-44, 1983)
Key words. intrathecal
computerized tomography empty sella metrizamide computed tomography sagittal CT reconstruction l
l
l
B
demonstrates the degree of herniation into the sella turcica and particularly the relationships of surThe following case illusrounding structures. 1,4,6,7,11 trates the superiority of intrathecal metrizamide and sagittal multiplanar reconstruction CT views in the evaluation of empty sella syndrome.
usch in 1951 first employed the term “empty sella” to describe a condition in which the diaphragma sellae was reduced to a small rim of peripheral tissue and the pituitary gland was flattened along the sellar floor.3 Clinically, the diagnosis of this condition rested on the demonstration of an enlarged sella on skull x-rays and air which filled or partially filled the pituitary fossa during pneumoencephalography. ‘,‘OComputed tomography has replaced air contrast studies in the diagnosis of empty sella.l*gJo However, conventional computed tomography, even with our present three millimeter sections, cannot differentiate an empty sella from a necrotic pituitary adenoma or other low density intrasellar lesions, especially if the infundibulum is not well visualized.4,8 The empty sella is not truly “empty,” but consists of an extension of the subarachnoid space through a defective diaphragma sellae. Contrast material (metrizamide) injected within the subarachnoid space more convincingly
Case Report A 38-year-old obese woman was seen in consultation after she developed transient obscurations of vision. Her visual acuities were 20/20 (6/6) OU and she had bilateral papilledema. Conventional axial CT scan revealed an area isodense to cerebrospinal fluid (CSF) partially filling the sella turcica. The relatively hypodense area was found within the sella using sagittal reconstruction (Fig. 1). Metrizamide was introduced into the subarachnoid space and sagittal reconstruction of the computed axial views was repeated.5 The subarachnoid space extended through the presumably defective diaphragma sel42
EMPTY
SELLA
Key to labels: A = Hypodense area within the sella turcica; B = Dorsum sellae; E = Tuberculum sellae; F = Posterior clinoid; G = Planum sphenoidale; H = Basilar artery; I = Metrizamide-containing subarachnoid space within the sella turcica; J = Pituitary gland; K = Pons; L = Mamillary bodies; M = Infundibulum; N = Chiasm
Fig. 1. Sagittal reconstruction with intravascular contrast (conray). The hypodense area (A) extends through most of the sella turcica. The position of the pituitary gland cannot be distinguished as the infundibulum is not visualized. The chiasm is not seen. Note that the basilar artery is filled with contrast (H).
Fig. 2. Sagittal reconstruction with intrathecal water soluble contrast (metrizamide). The degree of extension of subarachnoid space into the sella turcica is outlined by metrizamide (I). The pituitary gland (J) is compressed along the floor and walls of the sella turcica and the negative shadow corresponding to the infundibulum is well visualized (M). Within the suprasellar cistern is the negative shadow ofthe optic chiasm (N). Note the basilar artery (H) is seen as a negative shadow outlined by contrast in the prepontine cistern (compare with Fig. 1).
lae, well delineated by metrizamide (Fig. 2). The pituitary gland was compressed against the floor and dorsum sellae. The chiasm was outlined by metrizamide and did not appear to be dragged into the “empty” sella. Cerebrospinal fluid pressure was 320 mm of water. The diagnosis was consistent with pseudotumor cerebri associated with empty sella. The empty sella needs to be clearly separated from other causes of an enlarged sella. The diagnosis of empty sella can be suggested with computed
tomography using reconstruction views without pneumoencephalography. Injection of metrizamide by lumbar puncture permits precise visualization of the pericerebral cisterns and the structures in and around the sella turcica. Metrizamide contrast studies help define the intracranial anatomy, differentiate spaces from masses, and can demarcate the extent of mass lesions more clearly than was possible with earlier studies. Indications for the use of metrizamide con-
44
Surv Ophthdmol
28 (1) July-August
1983
trast in the empty sella include a need to define the location of the chiasm in the case of visual 10s~;~ differentiation of the truly empty sella from low density intrasellar lesions such as a lucent chromophobe adenoma, craniopharyngioma, or necrotic tumor (especially if the infundibulum is not well visualized); and delineation of the lateral, rostra& caudal, and superior extent of intrasellar mass lesions, especially those which are hypodense or isodense to the CSF.@
References Bajraktari X, Bergstrom M, Brismar K, et al: Diagnosis of intrasellar cisternal herniation (empty sella) by computer assisted tomography. J Cornput Assist 7’omogr 1:105-l 16, 1977 Bursztyn EM, Lavyne MH, Aisen M: Empty sella syndrome with intrasellar herniation of the optic chiasm. Am JNeuroradiol 4:167-168, 1983 Busch W: Die Morphologie der Sella Turcica und ihre Beziehungen zur Hypophyse. Virchows Arch Pathol Anat 320:437-458, 1951 Chui M, Pate1 HM: Computed tomography of sellar and parasellar lesions: Indications for metrizamide cisternography. J Can
PRICE
ET AL
Assoc Radio1 33:84-88, 1982 5. Di Chiro G, Schellinger D: Computed tomography of spinal cord after lumbar intrathecal introduction of metrizamide (computer assisted myelography). Radiology 220: 101-104, 1976 6. Ghoshhajra K: High-resolution metrizamide CT cisternography in sellar and suprasellar abnormalities. J Neurosurg 54232-239, 1981 7. Gross CE, Binet EF, Esguerra JV: Met&amide cisternography in the evaluation of pituitary adenomas and the empty selia syndrome. J Neurosurg 50:472-476, 1979 8. Guibert-Tranier F, Elie G, Guibert JL, Piton J, CaillC JM: The empty sella: CT diagnosis. J Neuroradiol 7: 105119, 1980 9. Ketonen L, Kuuliala I: Diagnosis of primary empty sella syndrome by computed tomography. Ann Clin Res II: 125-128,1979 10. Rozario R, Hammerschlag SB, Post KD, et al: Diagnosis of empty sella with CT scan. Neuroradiology 13:85-88, 1977 11. Young WF, Ospina LF, Wesolowski D, Towma A: The primary empty sella syndrome: Diagnosis with metrizamide cisternography. JAMA 246:2611-2612, 1981
This investigation was supported in part by Foundation for the Prevention of Blindness (Dr. Reprint requests should be addressed to: James Department of Neurology, University of Iowa, 52242.
the E. A. Baker Price). J. Corbett, M.D., Iowa City, Iowa