ClinicalRadiology(1992) 46, 213-215
Case Report: The Vanishing Ring Sign-An Unusual CT Manifestation of Multiple Sclerosis K. GOWER
THOMAS
a n d G . J. G R I F F I T H S
Department of Radiology, Royal Gwent Hospital, Newport, Gwent Ring-like computed tomographic (CT) enhancement of a solitary cerebral mass usually indicates neoplasm or abscess. A 64-year-old man with this sign was found to have multiple sclerosis (MS), and following oral steroid treatment, it disappeared. G o w e r T h o m a s K. & G r i f f i t h s G . J . (1992). Clinical Radiology 46, 2 1 3 - 2 1 5 . C a s e R e p o r t : T h e V a n i s h i n g R i n g Sign-An Unusual CT Manifestation of Multiple Sclerosis
Correspondence to: K. Gower Thomas, 8 Roundel Close, Thornhill, Cardiff CF4 9ES.
present. His right hand exhibited mild dysdiadochokinesia and there was evidence of posterior column loss in both legs. The lower limb reflexes were brisker than those in the upper limbs, and the Babinski reflex was elicited on both sides. The visual evoked responses were delayed bilaterally. A working diagnosis of multiple sclerosis was made on clinical grounds. Computed cranial tomography showed a 2.7 cm diameter area of low attenuation in the parieto-occipital part of the left cerebral hemisphere which exhibited ring enhancement following intravenous iodine injection (single dose, immediate scanning); a rim of reduced attenuation surrounded the ring (Fig. 1). Five days later, magnetic resonance imaging (MRI) revealed, in addition to the left parietal lesion, a shower of white matter lesions in both cerebral and cerebellar hemispheres, some of which were periventricutar in situation (Fig. 2). Follow-up CT scanning 4 weeks later, after the patient had received a course of oral steroids, indicated that the left parietal lesion had diminished in size and no longer enhanced (Fig. 3). A further CT scan 11 weeks later showed no abnormality. These changes corresponded to the patient's improved clinical picture; he had less difficulty in walking and speaking, but continued to experience numbness in his feet and hands.
(a)
(b)
A s o l i t a r y c o m p u t e d t o m o g r a p h i c ( C T ) r i n g l e s i o n is a n unusual manifestation of multiple sclerosis [t-3]. Especially i f e x e r t i n g a m a s s effect, s u c h a l e s i o n m a y p r o m p t an incorrect diagnosis. CASE REPORT A 64-year-old man presented with a 2 week history of increasing unsteadiness and speech difficulty, including sporadic slurring. For 9 years he had suffered from numbness and paraesthesiae in his fingers and feet and a left abducent palsy had once been found which lasted 6 weeks. He was receiving treatment for hypertension, and cervical spondylosis had previously been noted. Physical examination revealed arterial hypertension (180/100 mm Hg), and confirmed a mild non-fluent dysphasia with some dysarthria. His gait was unsteady and broad-based, and Romberg's sign was
Fig. 1 -(a) Unenhanced CT brain scan, showing low attenuation lesion in the left parietal lobe, exerting some mass effect. (b) Enhanced slice made at the same level, showing ring enhancement.
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CLINICAL RADIOLOGY
(a)
Fig. 3-Same case. Enhanced CT brain scan on the same level, made 4 weeks later following oral steroid therapy. The mass lesion is smaller and does not enhance.
DISCUSSION
(b) Fig. 2-Same case. Axial T2-weighted MR scan, returning a hyperintense signal from the left parietal lesion, which is surrounded by oedema. Additional numerous smaller lesions are present in the white matter of both cerebral hemispheres.
The CT picture o f a cerebral mass exhibiting ring enhancement and circumferential oedema m o s t comm o n l y represents a t u m o u r or an abscess. Such appearances are extremely unusual in multiple sclerosis which m a y show no C T abnormality at all or, following a double dose o f iodine and delayed scanning, m a y reveal periventrieular areas o f low density. The C T ring sign even when solitary is an unusual manifestation o f MS: it is t h o u g h t to represent a b r e a k d o w n in the blood/brain barrier at the stage o f acute demyelination, which permits the iodine to extravasate t h r o u g h the altered endothelium [4]. After treatment with steroids, the ring vanishes because the integrity of this barrier is re-established [5]. In our patient the clinical signs and s y m p t o m s did not correlate accurately with the initial C T findings. This is an i m p o r t a n t negative finding, because patients exhibiting a solitary C T ring lesion are often submitted to immediate brain biopsy or c r a n i o t o m y for further evaluation. With the advent o f M R scanning, this m a y no longer occur as frequently. O u r patient was elderly, c o m p a r e d to the c u s t o m a r y age o f onset o f MS. In MS patients, the c o m b i n a t i o n o f a C T ring sign with a speech disorder has been linked w i t h rapid clinical deterioration; a third o f patients dying within 15 m o n t h s in one series [2]. D e a t h in such patients might easily be attributed to malignancy, both clinically and radiologically, if the possibility of M S is not actively considered and excluded.
VANISHING RING SIGN
REFERENCES" 1 Sagar HJ, Warlow CP, Sheldon PWE, Esiri MM. Multiple sclerosis with clinical and radiological features of cerebral tumour. Journal of Neurology, Neurosurgery and Psychiatry 1982;45:802-808. 2 Giitling E, Landis T. CT using sign imitating tumour, disclosed as multiple sclerosis by MRI: a case report. Journal of Neurology, Neurosurgery and Psychiatry 1989;52:903 906. 3 Lecky BRF, Jeyagopal N, Smith ETC, Foy PM. Cerebral CT lesions
215
in multiple sclerosis mimicking multiple metastases. Journal of Neurology, Neurosurgery and Psychiatry 1991 ;54:92. 4 Aita JF, Bennett DR, Anderson RE, Ziter F. Cranial CT appearance of acute multiple sclerosis. Neurology (Minneapolis) 1978;28: 251-252. 5 Sears ES, Tindall RSA, Zarnow M. Active multiple sclerosis. Enhanced computerised tomographic imaging of lesions and the effect of corticosteroids. Archives of Neurology 1978;35:426 434.
Case Report: The Vanishing Ring Sign-An Unusual CT Manifestation of Multiple Sclerosis K. GOWER
THOMAS
a n d G . J. G R I F F I T H S
Department of Radiology, Royal Gwent Hospital, Newport, Gwent Ring-like computed tomographic (CT) enhancement of a solitary cerebral mass usually indicates neoplasm or abscess. A 64-year-old man with this sign was found to have multiple sclerosis (MS), and following oral steroid treatment, it disappeared. G o w e r T h o m a s K. & G r i f f i t h s G . J . (1992). Clinical Radiology 46, 2 1 3 - 2 1 5 . C a s e R e p o r t : T h e V a n i s h i n g R i n g Sign-An Unusual CT Manifestation of Multiple Sclerosis
Correspondence to: K. Gower Thomas, 8 Roundel Close, Thornhill, Cardiff CF4 9ES.
present. His right hand exhibited mild dysdiadochokinesia and there was evidence of posterior column loss in both legs. The lower limb reflexes were brisker than those in the upper limbs, and the Babinski reflex was elicited on both sides. The visual evoked responses were delayed bilaterally. A working diagnosis of multiple sclerosis was made on clinical grounds. Computed cranial tomography showed a 2.7 cm diameter area of low attenuation in the parieto-occipital part of the left cerebral hemisphere which exhibited ring enhancement following intravenous iodine injection (single dose, immediate scanning); a rim of reduced attenuation surrounded the ring (Fig. 1). Five days later, magnetic resonance imaging (MRI) revealed, in addition to the left parietal lesion, a shower of white matter lesions in both cerebral and cerebellar hemispheres, some of which were periventricutar in situation (Fig. 2). Follow-up CT scanning 4 weeks later, after the patient had received a course of oral steroids, indicated that the left parietal lesion had diminished in size and no longer enhanced (Fig. 3). A further CT scan 11 weeks later showed no abnormality. These changes corresponded to the patient's improved clinical picture; he had less difficulty in walking and speaking, but continued to experience numbness in his feet and hands.
(a)
(b)
A s o l i t a r y c o m p u t e d t o m o g r a p h i c ( C T ) r i n g l e s i o n is a n unusual manifestation of multiple sclerosis [t-3]. Especially i f e x e r t i n g a m a s s effect, s u c h a l e s i o n m a y p r o m p t an incorrect diagnosis. CASE REPORT A 64-year-old man presented with a 2 week history of increasing unsteadiness and speech difficulty, including sporadic slurring. For 9 years he had suffered from numbness and paraesthesiae in his fingers and feet and a left abducent palsy had once been found which lasted 6 weeks. He was receiving treatment for hypertension, and cervical spondylosis had previously been noted. Physical examination revealed arterial hypertension (180/100 mm Hg), and confirmed a mild non-fluent dysphasia with some dysarthria. His gait was unsteady and broad-based, and Romberg's sign was
Fig. 1 -(a) Unenhanced CT brain scan, showing low attenuation lesion in the left parietal lobe, exerting some mass effect. (b) Enhanced slice made at the same level, showing ring enhancement.
214
CLINICAL RADIOLOGY
(a)
Fig. 3-Same case. Enhanced CT brain scan on the same level, made 4 weeks later following oral steroid therapy. The mass lesion is smaller and does not enhance.
DISCUSSION
(b) Fig. 2-Same case. Axial T2-weighted MR scan, returning a hyperintense signal from the left parietal lesion, which is surrounded by oedema. Additional numerous smaller lesions are present in the white matter of both cerebral hemispheres.
The CT picture o f a cerebral mass exhibiting ring enhancement and circumferential oedema m o s t comm o n l y represents a t u m o u r or an abscess. Such appearances are extremely unusual in multiple sclerosis which m a y show no C T abnormality at all or, following a double dose o f iodine and delayed scanning, m a y reveal periventrieular areas o f low density. The C T ring sign even when solitary is an unusual manifestation o f MS: it is t h o u g h t to represent a b r e a k d o w n in the blood/brain barrier at the stage o f acute demyelination, which permits the iodine to extravasate t h r o u g h the altered endothelium [4]. After treatment with steroids, the ring vanishes because the integrity of this barrier is re-established [5]. In our patient the clinical signs and s y m p t o m s did not correlate accurately with the initial C T findings. This is an i m p o r t a n t negative finding, because patients exhibiting a solitary C T ring lesion are often submitted to immediate brain biopsy or c r a n i o t o m y for further evaluation. With the advent o f M R scanning, this m a y no longer occur as frequently. O u r patient was elderly, c o m p a r e d to the c u s t o m a r y age o f onset o f MS. In MS patients, the c o m b i n a t i o n o f a C T ring sign with a speech disorder has been linked w i t h rapid clinical deterioration; a third o f patients dying within 15 m o n t h s in one series [2]. D e a t h in such patients might easily be attributed to malignancy, both clinically and radiologically, if the possibility of M S is not actively considered and excluded.
VANISHING RING SIGN
REFERENCES" 1 Sagar HJ, Warlow CP, Sheldon PWE, Esiri MM. Multiple sclerosis with clinical and radiological features of cerebral tumour. Journal of Neurology, Neurosurgery and Psychiatry 1982;45:802-808. 2 Giitling E, Landis T. CT using sign imitating tumour, disclosed as multiple sclerosis by MRI: a case report. Journal of Neurology, Neurosurgery and Psychiatry 1989;52:903 906. 3 Lecky BRF, Jeyagopal N, Smith ETC, Foy PM. Cerebral CT lesions
215
in multiple sclerosis mimicking multiple metastases. Journal of Neurology, Neurosurgery and Psychiatry 1991 ;54:92. 4 Aita JF, Bennett DR, Anderson RE, Ziter F. Cranial CT appearance of acute multiple sclerosis. Neurology (Minneapolis) 1978;28: 251-252. 5 Sears ES, Tindall RSA, Zarnow M. Active multiple sclerosis. Enhanced computerised tomographic imaging of lesions and the effect of corticosteroids. Archives of Neurology 1978;35:426 434.
