Spinal MRI in vacuolar myelopathy, and correlation with histopathological findings

We correlated MRI features with histopathological findings in an HIV-positive patient with vacuolar myelopathy. On MRI symmetrical nonenhancing high-signal areas in the posterior columns on T2-weighted images result from extensive vacuolation visible on histological sections. Received: 18 November 1997 Accepted: 23 March 1997     

Imaging of thoracic and lumbar spinal extradural arachnoid cysts: report of two cases

Extradural arachnoid cysts are uncommon expanding lesions in the spinal canal which may communicate with the subarachnoid space. Usually in the lower thoracic spine, they may cause symptoms by compressing the spinal cord or nerve roots. We report cases of thoracic and lumbar arachnoid cysts studied by cystography, myelography, CT and MRI. These techniques showed extradural cystic lesions containing cerebrospinal fluid, with variable communication with the subarachnoid space, causing anterior displacement and flattening of the spinal cord. Received: 3 November 1995 Accepted: 16 April 1996     

Neurosarcoma of the face: MRI

Neurosarcoma is a rare tumour originating from the sheath of peripheral nerves. Facial lesions have been reported in about 20 patients. We describe the MRI appearances of neurosarcoma with histological correlation in three patients. The lesions lay in the submandibular region, the left parapharyngeal space and the right orbit. MRI showed a well-defined mass with mixed components. The lesions were moderately heterogeneous on T1-weighted images in two cases and on T2-weighted images in all cases. Gadolinium enhancement occurred in all cases to variable degrees. In two cases, small high signal foci were seen on T2-weighted sequences. MRI appearances of neurosarcoma are not specific. Received: 3 September 1996 Accepted: 26 November 1996     

CT and MRI of the middle ear

Summary High-resolution computed tomography (HRCT) provides excellent contrast between osseous structures, air and soft tissue in conjunction with high spatial resolution. Therefore, thin-section HRCT with bone window setting is the method of choice for the examination of the middle ear structures. The indications are acute and chronic inflammatory changes, cholesteatoma and tumor, the “postoperative middle ear”, and malformations. In most cases, HRCT enables differentiation between inflammatory changes, cholesteatoma, and tumor. The excellent depiction of subtle osseous details enables the identification of erosions of the ossicles or of the bony walls of the mastoid cells, of osseous defects of the tegmen, of the bony labyrinth, and of the tympanic course of the facial canal. In addition, HRCT enables excellent depiction of reconstructions of the ossicles or prosthesis of the ossicles. Although HRCT is the first method of choice, magnetic resonance imaging (MRI) may provide additional information and lead to a more accurate diagnosis in some cases. This is explained by the excellent soft tissue contrast provided by MRI. In addition, MRI offers the possibility of using various pulse sequences and the administration of IV contrast material. Therefore, MRI may allow the differentiation between inflammatory changes, cholesteatoma, and tumor in those cases in which accurate diagnosis cannot be made by HRCT. The differentiation between a meningocele or meningoencephalocele and other entities such as tumors or cholesteatoma can be established by MRI. Furthermore, MRI can accurately depict cases of labyrinthitis or of neuritis of the facial nerve or of intracranial disease caused by middle ear processes, while this is not always possible by HRCT. In summary, HRCT of the middle ear is the method of choice, but MRI may provide supplementary information in those cases in which accurate diagnosis cannot be established by HRCT.      

磁刺激运动诱发电位在腰椎间盘突出所致的腰骶神经根病变中的应用研究

在35例有L5和／或S1神经根损害表现的腰椎间盘突出患者腰椎区进行磁刺激运动诱发电位（MEP）检查，测定、记录胫前肌、展肌和小趾展肌MEP的起始潜伏期（OL）。结果显示，35例中至少有一条总侧肌肉MEP异常33例（94．3％）。在L4－5椎间盘突出中，以胫前肌的MEP异常为主；在L5－S1椎间盘突出中，以小趾展肌的MEP异常为主。表明腰椎区MEP检查对腰椎间盘突出所致的腰骶神经根病变较为敏感，可为临床诊断提供可靠依据并有助于定位诊断。     

Temporal lobe epilepsy with varying severity: MRI study of 222 patients

MRI was performed in 222 consecutive adult patients with temporal lobe epilepsy of varying severity from January 1991 to May 1993. The diagnosis of hippocampal sclerosis was established visually by three independent observers. The accuracy of visual assessment of hippocampal asymmetry was compared with volumetric measurements. Neuropathological correlations were obtained in 63 patients with refractory seizures. Temporal lobe abnormalities were observed in 180 patients (81 %) as follows: hippocampal sclerosis in 122 (55 %); developmental abnormalities in 16 (7.2 %); tumours in 15 (6.8 %); scars in 11 (5 %); cavernous angiomas in 10 (4.5 %); miscellaneous lesions in 6. MRI was normal or showed unrelated changes in 42 patients (19 %). Visual assessment correctly lateralised hippocampal sclerosis in 79 of the 84 patients measured (94 %). Temporal lobectomy confirmed the MRI data (side and aetiology) in all 63 operated patients. Patients with normal MRI had an older age of seizure onset and were more often drug-responsive than patients with hippocampal sclerosis. MRI showed temporal lobe abnormalities in 81 % of epileptic patients with varying severity with good neuropathological correlation. Patients with normal MRI had a less severe form of the disease. Received: 19 August 1996 Accepted: 13 November 1996     

胼胝体发育不全的MRI表现

对６例胼胝体发育不全的ＭＲＩ表现进行了分析。矢位像可清楚显示胼胝体的形态学变化，冠位或矢位像较轴拉像更易确认三脑室的移位。ＭＲＩ的多方向成像和高组织分辩率较ＣＴ更有利于对胼胝体发育不全及所合并的其他中枢神经系统异常的诊断，故可做为首选的影像学检查方法。     

The somatotopic localisation of the descending cortical tract in the cerebral peduncle: a study using MRI of changes following Wallerian degeneration in the cerebral peduncle after a supratentorial vascular lesion

We studied the effects of Wallerian degeneration in the cerebral peduncle shown by magnetic resonance imaging (MRI) following a supratentorial vascular lesion, to identify the somatotopic localisation of the descending cortical tracts. Patients with a lesion involving a large area of a cerebral hemisphere had an area of abnormal signal intensity in the whole cerebral peduncle, suggesting Wallerian degeneration of all the whole descending cortical tracts. With a small lesion confined to the precentral gyrus, corona radiata, or posterior limb of the internal capsule there was an abnormal signal at the centre of the peduncle, suggesting degeneration of the precentrospinal tract. Those with a small lesion confined to the paracentral gyrus had an abnormal area slightly lateral to the centre of the peduncle, suggesting degeneration of the parietospinal tract. Patients with a lesion of the parietal or temporal lobes, not including the paracentral or precentral gyri, corona radiata, or the posterior limb of the internal capsule, had an abnormal area laterally in the peduncle, suggesting degeneration of the parietopontine or temporopontine tract.     

Development of an animal model for neuroleptic malignant syndrome: heat-exposed rabbits with haloperidol and atropine administration exhibit increased muscle activity, hyperthermia, and high serum creatine phosphokinase level

The neuroleptic malignant syndrome (NMS) is a life-threatening complication of neuroleptic treatment. To elucidate the pathogenesis of NMS, an animal model has been developed. Experimental rabbits treated with haloperidol (1 mg/kg) by intramuscular injection, were studied for the diagnostic symptoms of increased muscle rigidity, elevated body temperature, and high serum creatine phosphokinase (CPK) level. Administration of haloperidol (1 mg/kg) and atropine (0.4 mg/kg), and exposure to high ambient temperature (35°C) induced a significant increase in electromyographic activity with muscle rigidity similar to that observed in patients with NMS. Such rabbits also showed elevated body temperature and serum CPK value. In addition to the similarity of the signs and symptoms, all parameters measured (muscle rigidity, body temperature, and serum CPK level) were normalized by dantrolene treatment. The effectiveness of dantrolene in the experimental animal partially confirms the validity of this animal model for NMS. This experimental animal model for NMS may be useful to elucidate the pathogenesis of NMS.     

乳腺占位病变的高场强MRI诊断价值

目的 :总结乳腺良恶性占位病变在高场强MRI的影像表现 ,评价高场强MRI对乳腺良恶性病变的诊断价值。方法 :搜集1996～ 2 0 0 4年间经手术病理证实的 4 3例乳腺良恶性占位病变的MRI资料 ,分析其影像表现。结果 :典型乳腺良、恶性病变 ,高场强MR平扫即能准确诊断 ,而部分非典型良、恶性病灶 ,增强扫描形态、信号变化也有一定的重叠。结论 :MRI技术能够充分显示病变形态及与周围组织结构之间的关系 ,是建议活检或预防性手术的最有力的依据。但是 ,MRI平扫、增强技术对乳腺非典型病变 ,仍然有局限性