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The false sulcus: An early sign of intracranial mass
JOURNAL
OF COMPUTED
TOMOGRAPHY
1983;7:145-148
THE FALSE SULCUS: AN EARLY SIGN OF INTRACRANIAL MASS TOHN F. HEALY
The importance of asymmetry of the cerebral sulci in detecting intracranial mass lesions in the hemisphere where the mass compresses the sulci has been emphasized. Occasionally, the hemisphere that appears to have the large sulci is, in fact, the abnormal side. The apparent large sulci representing early white matter edema are often the earliest computed tomography manifestation of an intracranial mass. KEY WORDS:
Tumor: Vertex; Edema; Sulcus; Computed tomography; Cranial computed tomography; White matter
One should view every patient with asymmetrical sulci over the cerebral convexities with suspicion and perform double-contrast scans, delayed scans, isotope brain scans, or follow-up computed tomography (CT) scans if clinically indicated. Some patients will have no intracranial mass, others will have atrophy on the side of the larger sulcus, and still others will have a mass on the side of the obliterated sulci; but a few patients will have a mass on the side of the apparent sulcal enlargment. In these cases, the sulci are not actually enlarged. Instead, early white matter edema that may possibly be misinterpreted as sulcal enlargement is present. It is well known that asymmetry of the sulci high in the convexity is very helpful in detecting masses that obliterate sulci on the involved side (Figure 1).
From the Department of Radiology, University of California Medical Center, San Diego, California. Address reprint requests to: John F. Healy, MD, Radiology Department, Paradise Valley Hospital, 2400 E. 4th Street, National City, California 92050. Accepted October 1982. Q 1983 by Elsevier Science Publishing Co., Inc. 52 Vanderbilt Avenue, New York, NY 10017 0149-936x/83/020145-04$3.00
However, we have noted several cases in which the hemisphere with the apparent large sulci proved instead to have early white matter edema in response to a mass lesion that became obviovs only upon further investigation with scans (Figures 2, 3, and 4). It is important to realize that cerebral sulci must always extend to either the lateral or medial surface of a cerebral hemisphere (Figure 5). In many of these cases, the apparent large sulci should have been suspect because they did noti extend to a surface of the brain. Wing (1) emphasized the importlance of not omitting the vertex scan when performing cranial CT. He reviewed 2000 consecutive scans and found that the most significant or the sole abnormality was present on the vertex scan alone in 3% of the cases. He emphasized that omission of the vertex scan pair (2 slices) resulted in failure to vispalize IO--15% of brain volume. Interpretation of the vertex region can be difficult when only an axial view is available. With the advent of widespread use of fourth generation scanners and quick, adequate image reformation, the CT evaluation of the vertex region should improve, as it can be easily imaged in more than one projection if necessary. In a review of 200 patients with intracerebral metastases, 66 patients (33%) had white matter edema present on the top CT slice. Many of these patients had obvious enhancing lesions and white matter edema on lower adjoining slices. However, the three patients presented in this paper had no other findings on contrast enhanced scans. Because the apparent sulci did not extend to a cerebral surface, further investigation was undertaken. Rescanning after 2 weeks (case l), the administration of additional contrast medium (case 2), or delayed scanning in 1 hour (case 3) was necessary to fully appreciate the lesion. If these maneuvers do not define the disease, isotope scanning and careful clinical and radiological follow-up are indicated.
146
FIGURE 1C. Enhanced
scan 10 weeks later revealed
ob-
FIGURE 2A. Case 1. A 41-year-old man with retroperitoneal fibrosarcoma and new onset of right-sided seizures. Two “prominent sulci” (arrow) noted in left hemisphere on enhanced CT scan. Note that they do not extend to the surface of the cerebral hemisphere and thus should be suspected of being early white matter edema and not cortical sulci.
147
FIGURE 2B. Noncontrast scan 13 days later reveals obvious mass lesion with surrounding edema. New area of edema is now visible in the posterior right hemisphere.
FIGURE 2C. Contrast static fibrosarcoma.
enhancement
reveals
large meta-
FIGURE 3A. Case 2. Contrast scan in &-year-old man with recent resection of a bronchogenic carcinoma, now presenting with right upper extremity seizures. “Prominent sulcus” vs edema-low density in left hemisphere does not appear to extend to either the medial or lateral edge of the brain, thus white matter edema should be suspected.
FIGURE 3B. Double dose of contrast medium and 1 hour delayed scan reveals obvious enhancing mass lesion.
148
THE JOURNAL OF COMPUTED TOMOGRAPHY VOL.
FIGURE 4A. Case 3. A 72-year-old man with undifferentiated cancer of the lung. “Prominent sulcus” vs edema revealed on contrast enhanced scan in right hemisphere. No mass lesion seen. Note that “sulcus” does not extend to the edge of the brain, making edema more likely.
7
NO. 2
FIGURE 5. Large sulci in normal elderly patient. Note that all sulci, even very large sulci in right hemisphere, extend all the way to the surface of the brain.
REFERENCE 1. Wing SD, Osborn AG, Wing RW: The vertex scan: An im1portant component of cranial computed tomography. Am J Rclentgenol 130:765-767, 1978
FIGURE 4B. One hour delayed mass lesion.
scan reveals
enhancing
NO CONTINUING PROVIDED
MEDICAL EDUCATION QUESTIONS
OF COMPUTED
TOMOGRAPHY
1983;7:145-148
THE FALSE SULCUS: AN EARLY SIGN OF INTRACRANIAL MASS TOHN F. HEALY
The importance of asymmetry of the cerebral sulci in detecting intracranial mass lesions in the hemisphere where the mass compresses the sulci has been emphasized. Occasionally, the hemisphere that appears to have the large sulci is, in fact, the abnormal side. The apparent large sulci representing early white matter edema are often the earliest computed tomography manifestation of an intracranial mass. KEY WORDS:
Tumor: Vertex; Edema; Sulcus; Computed tomography; Cranial computed tomography; White matter
One should view every patient with asymmetrical sulci over the cerebral convexities with suspicion and perform double-contrast scans, delayed scans, isotope brain scans, or follow-up computed tomography (CT) scans if clinically indicated. Some patients will have no intracranial mass, others will have atrophy on the side of the larger sulcus, and still others will have a mass on the side of the obliterated sulci; but a few patients will have a mass on the side of the apparent sulcal enlargment. In these cases, the sulci are not actually enlarged. Instead, early white matter edema that may possibly be misinterpreted as sulcal enlargement is present. It is well known that asymmetry of the sulci high in the convexity is very helpful in detecting masses that obliterate sulci on the involved side (Figure 1).
From the Department of Radiology, University of California Medical Center, San Diego, California. Address reprint requests to: John F. Healy, MD, Radiology Department, Paradise Valley Hospital, 2400 E. 4th Street, National City, California 92050. Accepted October 1982. Q 1983 by Elsevier Science Publishing Co., Inc. 52 Vanderbilt Avenue, New York, NY 10017 0149-936x/83/020145-04$3.00
However, we have noted several cases in which the hemisphere with the apparent large sulci proved instead to have early white matter edema in response to a mass lesion that became obviovs only upon further investigation with scans (Figures 2, 3, and 4). It is important to realize that cerebral sulci must always extend to either the lateral or medial surface of a cerebral hemisphere (Figure 5). In many of these cases, the apparent large sulci should have been suspect because they did noti extend to a surface of the brain. Wing (1) emphasized the importlance of not omitting the vertex scan when performing cranial CT. He reviewed 2000 consecutive scans and found that the most significant or the sole abnormality was present on the vertex scan alone in 3% of the cases. He emphasized that omission of the vertex scan pair (2 slices) resulted in failure to vispalize IO--15% of brain volume. Interpretation of the vertex region can be difficult when only an axial view is available. With the advent of widespread use of fourth generation scanners and quick, adequate image reformation, the CT evaluation of the vertex region should improve, as it can be easily imaged in more than one projection if necessary. In a review of 200 patients with intracerebral metastases, 66 patients (33%) had white matter edema present on the top CT slice. Many of these patients had obvious enhancing lesions and white matter edema on lower adjoining slices. However, the three patients presented in this paper had no other findings on contrast enhanced scans. Because the apparent sulci did not extend to a cerebral surface, further investigation was undertaken. Rescanning after 2 weeks (case l), the administration of additional contrast medium (case 2), or delayed scanning in 1 hour (case 3) was necessary to fully appreciate the lesion. If these maneuvers do not define the disease, isotope scanning and careful clinical and radiological follow-up are indicated.
146
FIGURE 1C. Enhanced
scan 10 weeks later revealed
ob-
FIGURE 2A. Case 1. A 41-year-old man with retroperitoneal fibrosarcoma and new onset of right-sided seizures. Two “prominent sulci” (arrow) noted in left hemisphere on enhanced CT scan. Note that they do not extend to the surface of the cerebral hemisphere and thus should be suspected of being early white matter edema and not cortical sulci.
147
FIGURE 2B. Noncontrast scan 13 days later reveals obvious mass lesion with surrounding edema. New area of edema is now visible in the posterior right hemisphere.
FIGURE 2C. Contrast static fibrosarcoma.
enhancement
reveals
large meta-
FIGURE 3A. Case 2. Contrast scan in &-year-old man with recent resection of a bronchogenic carcinoma, now presenting with right upper extremity seizures. “Prominent sulcus” vs edema-low density in left hemisphere does not appear to extend to either the medial or lateral edge of the brain, thus white matter edema should be suspected.
FIGURE 3B. Double dose of contrast medium and 1 hour delayed scan reveals obvious enhancing mass lesion.
148
THE JOURNAL OF COMPUTED TOMOGRAPHY VOL.
FIGURE 4A. Case 3. A 72-year-old man with undifferentiated cancer of the lung. “Prominent sulcus” vs edema revealed on contrast enhanced scan in right hemisphere. No mass lesion seen. Note that “sulcus” does not extend to the edge of the brain, making edema more likely.
7
NO. 2
FIGURE 5. Large sulci in normal elderly patient. Note that all sulci, even very large sulci in right hemisphere, extend all the way to the surface of the brain.
REFERENCE 1. Wing SD, Osborn AG, Wing RW: The vertex scan: An im1portant component of cranial computed tomography. Am J Rclentgenol 130:765-767, 1978
FIGURE 4B. One hour delayed mass lesion.
scan reveals
enhancing
NO CONTINUING PROVIDED
MEDICAL EDUCATION QUESTIONS