Neurnradinlogy
Neuroradiology 14, 81-83 (1977)
® by Spr~ger-Veriag 1977
Computed-Tomography of Bilateral Isodense Chronic Subdural Hematomas H. Marcu and H. Becker Department of Neuroradiology, Radiological Center, Clinics of the Johann Wolfgang Goethe University, Frankfurt/M. FRG
Summary. While unilateral chronic isodense subdur-
al hematomas as a result of indirect signs of a spaceoccupying lesion are easily recognizable on computed tomography (CT) and clearly diagnosed on the angiogram, bilateral chronic isodense subdural hematomas may cause considerable difficulty. In two cases with CT false negative findings we observed, retrospectively, significant small cellae mediae and also the main part of the anterior horns sharply pointed and approaching one another. Three further cases showed the same ventricular configuration, which we called "hare's ears sign". This sign together with clinical data is always suspicious of chronic bilateral isodense subdural hematomas and carotid angiography is indicated. Other possible signs are: subtle midline shift if the size of the hematoma varies, changed formation of density of brain tissue, non-appearance of cerebral sulci especially in elderly patients, and eventually the visualization of a membrane after intrevenous injection of contrast material. Computed tomography - Bilateral isodense subdural hematoma - Indirect signs. Key words:
Computed tomography (CT) is today considered to be the method of choice for the diagnosis of intracranial hematomas. The acute subdural hematoma is easily recognizable due to the increased density of coagulated blood on the CT. The aging hematoma has a decreased density due to liquefaction so the chronic subdural hematoma is also easily recognizable from the decreased density in comparison with that of normal brain tissue. At certain stages, the density of the liquefied hematoma can be identical
to the density of brain tissue, so that such a bleeding cannot be directly visualized on CT. If such a hematoma is unilateral the signs of a space-occupying lesion, such as ventricular cempression, midline displacement, compresion of cisterns or asymmetry of sulci, suggest the diagnosis, which is confirmed by angiography. Bilateral isodense chronic subdural hematomas may cause considerable diagnostic difficulty because the hematoma itself is not demarcated, a midline displacement is not evident and the changes of the subarachnoid space may be symmetrical. Therefore false negative CT findings have been experienced by us and others [1, 2, 3, 4]. Therefore we looked for signs independant of tissue density, in particular the configuration of the ventricles. With cases of bilateral parietal chronic subdural hematomas we found a particular form of the ventricles.
Results of examination
Of the 7000 CT examinations (4000 with Siretom prototyp and 3000 with Siretom 1") there were two cases with isodense and three other cases with approximate isodense bilateral chronic subdural hematomas which were confirmed by operation. The CT pictures of two patients examined with the first CT machine were considered to be normal. On the basis of the clinical picture, carotid angiography was indicated and because of no apparent midline displacement, the other side was also investigated. In both cases bilateral parietal chronic subdural hematomas were discovered. Retrospectively the CT pictures of both cases showed distinctly small ventricular bodies and the main part of the anterior * financed by Volkswagenwerk foundation
82
H. Marcu and H. Becker: Bilateral Isodense Chronic Subdural Hematomas
horns was sharply pointed and they approached one another. We had never found such a form of the lateral ventricles on normal CT examinations. In the follow-up study we paid attention to this particular form of the lateral ventricles which simulate the ears of a hare, which we found with three other cases. Three cases were examined with the Siretom 1 (matrix 128 × 128).
tem with compression of the ventricular bodies, especially the left, and sharply pointed anterior horns, the sign of hare's ears. There was right parietal minimal low density, but no change following an intravenous injection of contrast. There was no sign of metastasis. Carotid arteriography revealed typical bilateral subdural hematomas.
Discussion Case 1
A man, aged 76, without history or evidence of trauma, had headaches, and a left latent hemiparesis with Babinski. The CT (Fig. 1) disclosed relatively small ventricular bodies with sharply pointed anterior horns which simulated the ears of a hare. Bilateral parietal subdural hematomas were demonstrated by carotid angiography. Case 2
A man, aged 23, who sustained a head injury 3 months previously, suffered from headaches and had papilledema. CT (Fig. 2) revealed normal appearing density of brain tissue without midline displacement, but there was the typical sign of hare's ears. Carotid angiography disclosed bilateral subdural hematomas. Case 3
A woman, aged 69, had an operation for breast cancer 2 months previously. Two months before that she had a very slight injury to the head which was followed by headaches and some mental confusion. Examination revealed papilledema and a fight Babinski. CT (Fig. 3) demonstrated a small ventricular sys-
Bilateral isodense chronic subdural hematomas without midline displacement has been considered impossible to diagnose by CT, but our experience had demonstrated that with meticulous observation of the form of the lateral ventricles this diagnosis can be ventured on CT. Distinctly small ventricular bodies with the main part of anterior horns sharply pointed and approaching one another were found in all cases with bilateral isodense chronic subdural hematomas located predominantly in the parietal region. The trigone was also included in this narrowing, but the other segments of lateral ventricles were normal. Naturally on the basis of clinical data in such cases bilateral carotid angiography is recommended. But the "hare's ears sign" is present only when the hematomas are located predominantly in the parietal region. This particular form of the ventricles was not seen with bilateral hematomas in other locations, but was found occasionally with parietal metastasis and acute hematomas. In such cases a correct dignosis could be easily made on the basis of modified density. Differential diagnosis must also be made with microventricles, but the clinical data are always of great value in such cases. If the size of the bilateral chronic subdural hematomas is different, a relatively subtle midline shift may be seen. This is a helpful indication of a second contralateral hematoma. The intravenous injection of contrast media to visualize a possible
H. Marcu and H. Becker: Bilateral Isodense Chronic Subdural Hematomas
membrane of the hematoma [3, 4, 5] was not applied. Furthermore it could be of some importance to observe the width of the cerebral sulci, especially in elderly patients since the non-appearance of the sulci together with the ventricular configuration described above would support the suspected diagnosis. The so-called "hare's ears sign" has a special significance for avoiding a false negative CT finding with bilateral isodense chronic subdural hematomas. Acknowledgement. Thanks to the Department of Neurosurgery for using the operation reports.
References 1. David, O.D., Pressman, B.D.: Computerized tomography of the brain. Radiol. Clin. North Amer. 12, 297-313 (1974) 2. Elke, M., Hiinig, R., Wiggli, U., Miiller, H.R., Wiithrich, R.: Die computerisierte Tomographie des Schfidels: eine neue Dimension der R6ntgentechnik. R6ntgenpraxis 29, 1-11 (1976)
83
3. Grumme, Th., Lanksch, W., Aulich, A.: The diagnosis of chronik subdural hematoma by comuterized axial tomography. In: Cranial computerized tomography (ed.: W.Lanksch, E. Kazner) pp. 337-341. Berlin, Heidelberg, New York: Springer, 1976 4. Grumme, Th., Lanksch, W. Kazner, E., Aulich, A., Meese, W., Lange, S., Steinhoff, H., Wende, S.: Zur Diagnose des chronischen subduralen H~imatoms im Computer-Tomogramm. Neurochirurgia 19, 95-103 (1976) 5. Komatsu, K., Matsunaga, M., Tanaka, K. Yoshida, R., Ohata, M., Inaba, Y.: Computed tomography diagnosis of chronic subdural hematoma in nontumoral diseases of the brain, spinal cord and eye. Bethesda, Maryland, Oct. 11-15, 1976
Received: April 9, 1977
Harry Marcu, M.D. Clinics of Johann Wolfgang Goethe-University Radilogical Center Department of Neuroradiology Schleusenweg 2-16 D - 6000 Frankfurt am Main 71 Federal Republic of Germany
Neuroradiology 14, 81-83 (1977)
® by Spr~ger-Veriag 1977
Computed-Tomography of Bilateral Isodense Chronic Subdural Hematomas H. Marcu and H. Becker Department of Neuroradiology, Radiological Center, Clinics of the Johann Wolfgang Goethe University, Frankfurt/M. FRG
Summary. While unilateral chronic isodense subdur-
al hematomas as a result of indirect signs of a spaceoccupying lesion are easily recognizable on computed tomography (CT) and clearly diagnosed on the angiogram, bilateral chronic isodense subdural hematomas may cause considerable difficulty. In two cases with CT false negative findings we observed, retrospectively, significant small cellae mediae and also the main part of the anterior horns sharply pointed and approaching one another. Three further cases showed the same ventricular configuration, which we called "hare's ears sign". This sign together with clinical data is always suspicious of chronic bilateral isodense subdural hematomas and carotid angiography is indicated. Other possible signs are: subtle midline shift if the size of the hematoma varies, changed formation of density of brain tissue, non-appearance of cerebral sulci especially in elderly patients, and eventually the visualization of a membrane after intrevenous injection of contrast material. Computed tomography - Bilateral isodense subdural hematoma - Indirect signs. Key words:
Computed tomography (CT) is today considered to be the method of choice for the diagnosis of intracranial hematomas. The acute subdural hematoma is easily recognizable due to the increased density of coagulated blood on the CT. The aging hematoma has a decreased density due to liquefaction so the chronic subdural hematoma is also easily recognizable from the decreased density in comparison with that of normal brain tissue. At certain stages, the density of the liquefied hematoma can be identical
to the density of brain tissue, so that such a bleeding cannot be directly visualized on CT. If such a hematoma is unilateral the signs of a space-occupying lesion, such as ventricular cempression, midline displacement, compresion of cisterns or asymmetry of sulci, suggest the diagnosis, which is confirmed by angiography. Bilateral isodense chronic subdural hematomas may cause considerable diagnostic difficulty because the hematoma itself is not demarcated, a midline displacement is not evident and the changes of the subarachnoid space may be symmetrical. Therefore false negative CT findings have been experienced by us and others [1, 2, 3, 4]. Therefore we looked for signs independant of tissue density, in particular the configuration of the ventricles. With cases of bilateral parietal chronic subdural hematomas we found a particular form of the ventricles.
Results of examination
Of the 7000 CT examinations (4000 with Siretom prototyp and 3000 with Siretom 1") there were two cases with isodense and three other cases with approximate isodense bilateral chronic subdural hematomas which were confirmed by operation. The CT pictures of two patients examined with the first CT machine were considered to be normal. On the basis of the clinical picture, carotid angiography was indicated and because of no apparent midline displacement, the other side was also investigated. In both cases bilateral parietal chronic subdural hematomas were discovered. Retrospectively the CT pictures of both cases showed distinctly small ventricular bodies and the main part of the anterior * financed by Volkswagenwerk foundation
82
H. Marcu and H. Becker: Bilateral Isodense Chronic Subdural Hematomas
horns was sharply pointed and they approached one another. We had never found such a form of the lateral ventricles on normal CT examinations. In the follow-up study we paid attention to this particular form of the lateral ventricles which simulate the ears of a hare, which we found with three other cases. Three cases were examined with the Siretom 1 (matrix 128 × 128).
tem with compression of the ventricular bodies, especially the left, and sharply pointed anterior horns, the sign of hare's ears. There was right parietal minimal low density, but no change following an intravenous injection of contrast. There was no sign of metastasis. Carotid arteriography revealed typical bilateral subdural hematomas.
Discussion Case 1
A man, aged 76, without history or evidence of trauma, had headaches, and a left latent hemiparesis with Babinski. The CT (Fig. 1) disclosed relatively small ventricular bodies with sharply pointed anterior horns which simulated the ears of a hare. Bilateral parietal subdural hematomas were demonstrated by carotid angiography. Case 2
A man, aged 23, who sustained a head injury 3 months previously, suffered from headaches and had papilledema. CT (Fig. 2) revealed normal appearing density of brain tissue without midline displacement, but there was the typical sign of hare's ears. Carotid angiography disclosed bilateral subdural hematomas. Case 3
A woman, aged 69, had an operation for breast cancer 2 months previously. Two months before that she had a very slight injury to the head which was followed by headaches and some mental confusion. Examination revealed papilledema and a fight Babinski. CT (Fig. 3) demonstrated a small ventricular sys-
Bilateral isodense chronic subdural hematomas without midline displacement has been considered impossible to diagnose by CT, but our experience had demonstrated that with meticulous observation of the form of the lateral ventricles this diagnosis can be ventured on CT. Distinctly small ventricular bodies with the main part of anterior horns sharply pointed and approaching one another were found in all cases with bilateral isodense chronic subdural hematomas located predominantly in the parietal region. The trigone was also included in this narrowing, but the other segments of lateral ventricles were normal. Naturally on the basis of clinical data in such cases bilateral carotid angiography is recommended. But the "hare's ears sign" is present only when the hematomas are located predominantly in the parietal region. This particular form of the ventricles was not seen with bilateral hematomas in other locations, but was found occasionally with parietal metastasis and acute hematomas. In such cases a correct dignosis could be easily made on the basis of modified density. Differential diagnosis must also be made with microventricles, but the clinical data are always of great value in such cases. If the size of the bilateral chronic subdural hematomas is different, a relatively subtle midline shift may be seen. This is a helpful indication of a second contralateral hematoma. The intravenous injection of contrast media to visualize a possible
H. Marcu and H. Becker: Bilateral Isodense Chronic Subdural Hematomas
membrane of the hematoma [3, 4, 5] was not applied. Furthermore it could be of some importance to observe the width of the cerebral sulci, especially in elderly patients since the non-appearance of the sulci together with the ventricular configuration described above would support the suspected diagnosis. The so-called "hare's ears sign" has a special significance for avoiding a false negative CT finding with bilateral isodense chronic subdural hematomas. Acknowledgement. Thanks to the Department of Neurosurgery for using the operation reports.
References 1. David, O.D., Pressman, B.D.: Computerized tomography of the brain. Radiol. Clin. North Amer. 12, 297-313 (1974) 2. Elke, M., Hiinig, R., Wiggli, U., Miiller, H.R., Wiithrich, R.: Die computerisierte Tomographie des Schfidels: eine neue Dimension der R6ntgentechnik. R6ntgenpraxis 29, 1-11 (1976)
83
3. Grumme, Th., Lanksch, W., Aulich, A.: The diagnosis of chronik subdural hematoma by comuterized axial tomography. In: Cranial computerized tomography (ed.: W.Lanksch, E. Kazner) pp. 337-341. Berlin, Heidelberg, New York: Springer, 1976 4. Grumme, Th., Lanksch, W. Kazner, E., Aulich, A., Meese, W., Lange, S., Steinhoff, H., Wende, S.: Zur Diagnose des chronischen subduralen H~imatoms im Computer-Tomogramm. Neurochirurgia 19, 95-103 (1976) 5. Komatsu, K., Matsunaga, M., Tanaka, K. Yoshida, R., Ohata, M., Inaba, Y.: Computed tomography diagnosis of chronic subdural hematoma in nontumoral diseases of the brain, spinal cord and eye. Bethesda, Maryland, Oct. 11-15, 1976
Received: April 9, 1977
Harry Marcu, M.D. Clinics of Johann Wolfgang Goethe-University Radilogical Center Department of Neuroradiology Schleusenweg 2-16 D - 6000 Frankfurt am Main 71 Federal Republic of Germany
