Structural Connectivity and Cortical Thickness Alterations in Transient Global Amnesia.

BACKGROUND AND PURPOSE: Transient global amnesia (TGA) is a sudden onset of anterograde and retrograde amnesia. We aimed to assess differences in terms of cortical thickness and structural brain connectome between patients with TGA (at acute and delayed postrecovery stages) and matched controls. MATERIALS AND METHODS: We report on 18 consecutive patients with TGA who underwent 3T MR imaging, including DTI and MPRAGE sequences, at the acute (mean delay postonset: 44 hours) and delayed post-recovery (mean delay: 35 days) stages. Structural connectome was assessed in patients with TGA and in 18 age- and sex-matched controls by using probabilistic fiber- tracking and segmentation of 164 cortical/subcortical structures ("nodes"). Connectivity graphs were computed and global network metrics were calculated. Network-based statistical analysis (NBS) was applied to compare patients with TGA at each stage with controls. We also compared cortical thickness between patients with TGA and healthy controls. RESULTS: Global network metrics were not altered in patients with TGA. NBS-analysis showed structural connectome alterations in patients with TGA compared with controls, in core regions involving the limbic network, with 113 nodes and 114 connections (33 left intrahemispheric, 31 right intrahemispheric, and 50 interhemispheric connections) showing significantly decreased structural connectivity (P < .05 NBS corrected, t-values ranging from 3.03 to 8.73). Lower cortical thickness compared with controls was associated with these structural alterations in patients with TGA, involving the orbitofrontal, cingulate, and inferior temporal cortices. All the abnormalities were visible at both acute and delayed postrecovery stages. CONCLUSIONS: Our preliminary study suggests there are structural abnormalities of the limbic network in patients with TGA compared with controls, including decreased structural connectivity and cortical thickness.

Cerebral venous thrombosis after embolization of pediatric AVM with jugular bulb stenosis or occlusion: management and prevention.

PURPOSE: Thrombosis of cerebral arteriovenous malformation after embolization is rare, but can involve the normal venous network with extensive venous thrombosis. We report angioarchitecture findings, our management and prevention strategy for this complication in pediatric AVMs. METHODS: In this 5.5-year retrospective series, we reviewed records of 13 patients under 15 years who were anticoagulated after embolization. In our initial experience 4 children who didn't receive any prophylactic anticoagulation presented with extensive venous thrombosis after embolization (group 1). Following this, nine children with similar angioarchitecture and embolization modalities were treated with prophylactic anticoagulation immediately after embolization (group 2). We analyzed the type of AVM, angioarchitecture, dose of prophylactic anticoagulant, efficacy/complications of treatment and late outcome. RESULTS: All patients in group 1 had severe jugular bulb stenosis/occlusion associated with cerebral venous dilatation. In group 2 with similar angioarchitecture, only three patients (33%) developed extensive thrombosis. In both groups, thrombosis occurred within two days of treatment in six children and two weeks in one child. The diagnosis was suspected on intracranial hypertension in five patients and occulomotor disorder in one. One was asymptomatic. All children were treated with therapeutic doses of LMWH (anti-Xa: 0.5-1). No hemorrhagic complications occurred. Good venous remodeling was observed in all but one patient. CONCLUSION: Anticoagulation in extensive venous thrombosis after AVM embolization in children appears to be safe and effective. In cases with angioarchitectural features of dilatation of the cerebral venous network and occlusion/severe stenosis of the jugular bulbs, full dose anticoagulation may be required to prevent thrombosis.

Risk factors of hematomyelia recurrence and clinical outcome in children with intradural spinal cord arteriovenous malformations.

BACKGROUND AND PURPOSE: Few published data are available concerning the risk of re-bleeding of spinal cord AVM after an hematomyelia and concerning the long-term clinical outcome. Our aim was to assess the risk of recurrence and long-term clinical outcome after hematomyelia in children with spinal cord AVMs. MATERIALS AND METHODS: This single-center retrospective study reviewed the clinical and radiologic data of 28 children younger than 18 years of age with arteriovenous malformation who had experienced at least 1 episode of hematomyelia between 1988 and 2012. Long-term clinical outcome was assessed by the American Spinal Injury Association Impairment Scale, and radiologic review included MR imaging and angioarchitecture on angiography (blinded to clinical information) before treatment and at recurrence. RESULTS: Sixteen children (57%) experienced 1 episode of hematomyelia, while 12 children (43%) experienced recurrence. Girls and boys were equally affected (sex ratio, 1:1), and mean clinical follow-up was 5.7 ± 4.4 years. The risk of recurrence was higher for AVMs of the cervical and upper thoracic spine, 12 (100%) versus 11 (69%) (P = .01). A high American Spinal Injury Association scale score at last follow-up was reported for 11 children (39%), and the risk of recurrence tended to be associated with poorer functional prognosis (7 [64%] versus 5 [29%], P = .07). At the time of recurrence, perimedullary venous drainage was the main factor associated with recurrence (P = .002). Occlusion rate ≥50% was associated with a decreased risk of recurrence (P = .047). CONCLUSIONS: In the present series, cervical and upper thoracic spinal cord AVMs and microarchitecture were predictive of the risk of hematomyelia recurrence. Perimedullary venous drainage was one of the main parameters associated with recurrence. Functional prognosis was better in patients with a single episode of hematomyelia.

Significance of acute multiple infarcts in multiple cerebral circulations on initial diffusion weighted imaging in stroke patients.

OBJECTIVES: We attempted to assess the frequency, clinical and neuroradiological features of concomitant Acute Multiple Infarcts in Multiple Cerebral Circulations (AMIMCC) and to classify their causes. SUBJECTS AND METHODS: Consecutive patients treated for MR DWI-confirmed infarcts were included in this cohort. We retrospectively analyzed all patients with AMIMCC of our prospective database, studying clinical and radiological features. Causes of stroke were classified using TOAST and ASCO system (atherosclerosis, small vessel disease, cardiac source, other causes). RESULTS: Eighty AMIMCC were identified out of 824 consecutive patients with MR DWI-confirmed infarcts (9.7%). Compared with single infarct patients, AMIMCC patients presented similar age and risk factors. Only 24 AMIMCC patients (30%) presented symptoms suggesting multiple lesions before MRI. Cardiac origin existed in 39 of 80 patients (49%) including atrial fibrillation in 25 patients. Other sources of AMIMCC were hematologic diseases or coagulopathies such as intravascular coagulation in relation with cancer (n = 6; 7,5%) and vasculitis or systemic disorders (n = 5;6,5%). AMIMCC also appeared to originate from unilateral carotid diseases or intracranial stenosis, mostly atheromatous, in association with anatomic variations(n = 9;11%). In 21 patients, no cause was identified despite extensive investigations (26%). According to TOAST classification, 62% had a definite source for infarcts, 67% according to ASCO grade 1 classification. MRI data did not permit to orientate etiological explorations according to DWI appearance, associated leucoaraiosis or previous infarcts on FLAIR or microbleeding on gradient-echo sequences. CONCLUSIONS: AMIMCC are not rare and mostly need MRI to be detected. Multiple and various etiologies are implicated, including cardioembolic diseases in half of them, but also hematologic disorders and angeitis.

[Medical care of brain malformative vascular diseases discovered during the pre- or neonatal period]. / Prise en charge des malformations vasculaires cérébrales découvertes en période ante- ou néonatale.

Three types of brain arteriovenous vascular malformations can be found during the neonatal period, according to their anatomical location. Vein of Galen malformations are the most common. The others are pial arteriovenous malformations or dural arteriovenous malformations, which include dural sinus malformations. They can be asymptomatic, but most often they are associated with different symptoms, related to their angioarchitecture or their effect on the brain. High-flow arteriovenous malformations can thus be responsible for heart failure. Local or regional venous hyperpressure exposes the patient to subacute or chronic brain lesions, or to hydrovenous disorders such as hydrocephalus. Some types of venous reflux can expose patients to brain hemorrhage. The treatment chosen for these vascular malformations and their consequences is transarterial or transvenous embolization, depending on the angioarchitecture and type of lesion. The schedule for the treatment will be determined according to the malformation type and its local or general effects on the brain. The aim of this article is to present the recommendations of the French National Referral Center for neurovascular malformations in children, in order to help clinicians and radiologists treat these patients during pre- or neonatal period.

Pulse-triggered DTI sequence with reduced FOV and coronal acquisition at 3T for the assessment of the cervical spinal cord in patients with myelitis.

BACKGROUND AND PURPOSE: DTI is a promising technique for imaging of the spinal cord, but the technique has susceptibility-induced artifacts. We evaluated a pulse-triggered DTI sequence with an rFOV technique and coronal acquisition for the assessment of the cervical spinal cord in patients with myelitis at 3T. MATERIALS AND METHODS: A rFOV acquisition was established by a noncoplanar application of the excitation and the refocusing pulse in conjunction with outer volume suppression. The DTI sequence was performed in the coronal plane in 12 healthy volunteers and 40 consecutive patients with myelitis. Probabilistic tractography of the posterior and lateral funiculi was performed from the C1 to C7 levels. FA, MD, aD, rD, and ratios of aD and rD were measured. RESULTS: In healthy volunteers, mean DTI indices within the whole-fiber pathways were the following: FA = 0.61, MD = 1.17 × 10(-3) mm(2)/s, aD = 1.96 × 10(-3) mm(2)/s, rD = 0.77 × 10(-3) mm(2)/s, and ratios of aD and rD = 2.5. Comparison of healthy controls and patients with myelitis identified statistically significant differences for all DTI parameters. Different patterns of myelitis, including spinal cord atrophy and active inflammatory lesions, were recognized. There was a significant correlation between clinical severity and DTI parameters. CONCLUSIONS: The present work introduces a new approach for DTI of the cervical spinal cord at 3T, enabling a quantitative follow-up of patients with myelitis.

Short-term evolution of spinal cord damage in multiple sclerosis: a diffusion tensor MRI study.

INTRODUCTION: The potential of diffusion tensor imaging (DTI) to detect spinal cord abnormalities in patients with multiple sclerosis has already been demonstrated. The objective of this study was to apply DTI techniques to multiple sclerosis patients with a recently diagnosed spinal cord lesion, in order to demonstrate a correlation between variations of DTI parameters and clinical outcome, and to try to identify DTI parameters predictive of outcome. METHODS: A prospective single-centre study of patients with spinal cord relapse treated by intravenous steroid therapy was made. Patients were assessed clinically and by conventional MRI with DTI sequences at baseline and at 3 months. RESULTS: Sixteen patients were recruited. At 3 months, 12 patients were clinically improved. All but one patient had lower fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values than normal subjects in either inflammatory lesions or normal-appearing spinal cord. Patients who improved at 3 months presented a significant reduction in the radial diffusivity (p = 0.05) in lesions during the follow-up period. They also had a significant reduction in the mean ADC (p = 0.002), axial diffusivity (p = 0.02), radial diffusivity (p = 0.02) and a significant increase in FA values (p = 0.02) in normal-appearing spinal cord. Patients in whom the American Spinal Injury Association sensory score improved at 3 months showed a significantly higher FA (p = 0.009) and lower radial diffusivity (p = 0.04) in inflammatory lesion at baseline compared to patients with no improvement. CONCLUSION: DTI MRI detects more extensive abnormalities than conventional T2 MRI. A less marked decrease in FA value and more marked decreased in radial diffusivity inside the inflammatory lesion were associated with better outcome.

Diffusion MRI and tensor tractography in ischemic optic neuropathy.

Ischemic optic neuropathies (IONs) are among the most prevalent diseases causing visual impairment in middle-aged and elderly people. While arteritic ION is an ocular emergency and requires early diagnosis and immediate treatment with systemic high-dose corticosteroids to prevent further visual loss, treatment options for non-arteritic ION remain limited. We describe the case of a woman with unilateral right-sided non-arteritic posterior ischemic optic neuropathy. The diagnosis was made on clinical and radiographic grounds. Diffusion-weighted sequences and apparent diffusion coefficient maps revealed markedly restricted diffusion in the right optic nerve. It was very helpful to precise the posterior topography of the optic nerve lesion. Furthermore, we reported the diffusion tensor tractography study which appears to be an objective tool to assess the incomplete visual recovery. These MRI techniques including tensor tractography remain to be evaluated in large cohort of ION patients' particularly in future therapeutic trials.

External carotid artery branches involvement in reversible cerebral vasoconstriction syndrome.

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by segmental vasoconstriction and dilatation of intracranial arteries, usually revealed by headaches, which spontaneously resolve in few weeks. We report a patient with RCVS, revealed by thunderclap headaches, involving both internal and external carotid artery (ECA). She received fluoxetin for depression and took a great amount of cannabis in the last months. While angio-MR, transcranial Doppler and CSF analysis were normal, cerebral angiography disclosed stenoses and dilatations of the middle cerebral artery. It also showed an involvement of maxillary arteries. Fluoxetin and cannabis were stopped. After few days, she had no more headaches. At 8th week, angiography was normalized confirming the RCVS. ECA angiogram may help reaching a diagnosis in patients with suspected RCVS when intracerebral abnormalities are minor or absent.

Spontaneous thrombosis of an orbital arteriovenous malformation revealing hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber disease). A case report.

Hereditary Haemorrhagic Telangiectasia (HHT) is a genetic disorder responsible for cutaneous or mucosal telangiectasia and arteriovenous malformations (AVMs). The most frequent locations are lung and brain. In contrast, orbital AVMs are very rare. We describe a case of symptomatic orbital arteriovenous malformation due to spontaneous thrombosis. A 65-year-old woman was referred for chronic right eye proptosis associated with dilation of conjunctival vessels with a jellyfish pattern. Right visual acuity was 20/40 and intraocular pressure was 40 mmHg. Personal and familial history of recurrent epistaxis, associated with multiple telangiectasia within lips and palate, led to the diagnosis of HHT. Magnetic resonance imaging (MRI) completed with cerebral angiography found a giant and occluded AVM within the right orbit. Other AVMs were also found in brain and chest, confirming the diagnosis. Antiglaucomatous eyedrops were added to reduce intraocular pressure and a steroid therapy was begun. Two months later, visual acuity decreased in the right eye, due to a central retinal vein thrombosis. In conclusion, Most brain or pulmonary AVM can be treated by embolization. By contrast, this treatment in case of orbital location can lead to central retinal artery and/or central retinal vein occlusion, which may also appear as a spontaneous complication of the orbital AVM. Therapeutic management of orbital AVM is thus not standardized, and the balance between spontaneous and iatrogenic risk of visual loss has to be taken into account.

[Vascular emergencies of the head and neck]. / Urgences vasculaires cervicofaciales.

The clinical manifestations of vascular lesions of the head and neck may be variable (hemorrhagic, ischemic, compressive). Diagnosis often is made at the time of acute presentation, but delayed manifestations, sometimes long after the initial presentation, should not be overlooked. Hemorrhagic manifestations are characterized by epistaxis, corresponding mainly to lesions of the nasal cavities but involvement of the internal carotid artery should be excluded (life threatening). In addition, some vascular malformations may lead to severe hemorrhage. Ischemic manifestations typically result from arterial dissection. A venous origin is also possible. Carotid-cavernous fistulas rarely lead to hemorrhagic or ischemic manifestations and tend to result in ocular manifestations, typically delayed and sometimes misleading.

Aphasia in border-zone infarcts has a specific initial pattern and good long-term prognosis.

BACKGROUND: While border-zone infarcts (BZI) account for about 10% of strokes, studies on related aphasia are infrequent. The aim of this work was to redefine specifically their early clinical pattern and evolution. METHODS: We prospectively studied consecutive patients referred to our stroke unit within a 2-year period. Cases of aphasia in right-handed patients associated with a MRI confirmed left-sided hemispheric BZI were included. These patients had a standardized language examination in the first 48 h, at discharge from stroke unit and between 6 and 18 months later. RESULTS: Eight patients were included. Three had anterior (MCA/ACA), two posterior (MCA/PCA), two both anterior and posterior, and one bilateral BZI. All our patients initially presented transcortical mixed aphasia, characterized by comprehension and naming difficulties associated with preserved repetition. In all patients, aphasia rapidly improved. It fully recovered within a few days in three patients. Initial improvement was marked, although incomplete in the five remaining patients: their aphasias specifically evolved according to the stroke location toward transcortical motor aphasia for the three patients with anterior BZI and transcortical sensory aphasia for the two patients with posterior BZI. All patients made a full language recovery within 18 months after stroke. CONCLUSIONS: We report a specific aphasic pattern associated with hemispheric BZI, including an excellent long-term outcome. These findings appear relevant to (i) clinically suspect BZI and (ii) plan rehabilitation and inform the patient and his family of likelihood of full language recovery.

An atypical case of Foster Kennedy syndrome.

Foster-Kennedy syndrome was described in 1911 as an ophthalmologic manifestation of compression by a solid tumor in the frontal area with intracranial hypertension (ICHT). We describe a peculiar case of Foster-Kennedy syndrome associated with an arteriovenous malformation in which neither optic nerve compression nor ICHT was obvious. We discuss the different pathogenic mechanisms to explain this case, for which a chronic venous hypertension was the most probable etiology.

[Traumatic cord and nerve root injuries: imaging features at the acute and chronic phases]. / La moelle et les racines traumatiques: imagerie dans la prise en charge aiguë et chronique.

Cord injuries are frequent and severe lesions resulting in significant disability, most frequently in younger subjects. The area of cord injured results in clinical syndromes (Brown-Sequard, motor and/or sensory deficit...). Cord and rootlet injuries are best depicted on MRI. Diffusion tensor imaging with tractography enables depiction of the most severe cord lesions and some prediction of tissue viability which may provide an idea of the potential functional prognosis and patient recovery. MRI is optimal to demonstrate areas of cord hemorrhage or compression, partial or complete cord transsection, nerve root avulsion...

Diffusion tensor changes in epileptogenic hippocampus of TLE patients.

PURPOSE: Diffusion tensor imaging (DTI) can provide quantitative information of brain abnormalities in patients with temporal lobe epilepsy (TLE) that are not detectable with conventional magnetic resonance imaging (MRI). METHODS: Seventeen patients with medically TLE were selected for the study. The patients and ten healthy subjects underwent 25 directions DTI acquisition. The patients were separated into two groups based on the MRI findings: eight TLE MRI-negative patients with no signal abnormalities on conventional MRI and nine TLE patients with hippocampal sclerosis (HS). Fractional anisotropy (FA), mean diffusivity (MD), and the three diffusivities (lambda(1), lambda(2) and lambda(3)) were measured in bilateral hippocampi of controls, MRI-negative, and HS patients. Comparisons between the three groups were performed for hippocampi ipsi- and contralateral to epileptogenic zone. RESULTS: The ipsilateral hippocampus of MRI-negative patients presented statistical increased anisotropy and no significant difference in diffusivities versus controls. Significant differences in anisotropy and diffusivities were detected between the ipsilateral hippocampus of HS when compared with controls. CONCLUSION: DTI depicted hippocampal abnormalities in TLE patients with a normal conventional MRI different from those found in patients with HS. Diffusivity and anisotropy indices provide significant differences inside hippocampus and should be jointly considered to improve the DTI measurements specificity in TLE patients.

[Interest of tricuspid annular displacement (TAD) in evaluation of right ventricular ejection fraction]. / Evaluation de la fraction d'éjection ventriculaire droite par la mesure du déplacement de l'anneau tricuspide via l'utilisation du tricuspid annular displacement (TAD).

INTRODUCTION: The ultrasound assessment of RV structure and function is often sub-optimal. The range of excursions of the mitral or tricuspid annulus measured in millimetre by 2D or TM-mode in centimetre per second by DTI-mode echocardiography has been shown to reflect the systolic function of both ventricles. METHODS: We studied a new technique based on a tissue tracking algorithm that is ultrasound beam angle independent for automated detection of tricuspid annular displacement (TAD) (QLAB, Philips Medical Imaging). Twenty-six patients (pts) referred for magnetic resonance imaging (MRI) and 44 control subjects underwent a complete transthoracic echocardiography. MRI of the right ventricular ejection fraction (RVEF) was correlated by linear regression with TAD. Sixteen pts (61.5%) exhibited right ventricular systolic dysfunction (MRI RVEF<40%). RESULTS: The MRI RVEF was positively correlated with TAD (R(2)=0,65; p<0,0001). A value of TAD <14mm predicted right ventricular dysfunction with a sensitivity of 87.5% and a specificity of 90%. Most of (90%) healthy subjects exhibited TAD values exceeding this cut-off point (mean: 16.9+/-1.64mm; range: 13.3 to 24.8mm). Negative correlation was found between TAD and age (R(2)=0,36; p<0,0001). CONCLUSION: Our study is the first to correlate TAD with MRI RVEF. TAD is a simple, rapid, and non-invasive tool for right ventricular systolic function assessment.

Microvascular leakage and contrast enhancement as prognostic factors for recurrence in unfavorable low-grade gliomas.

Perfusion estimates and microvascular leakage (MVL) were recently correlated with glioma angiogenesis and aggressiveness, but their role in predicting outcome of patients (pts) with unfavorable low-grade gliomas (ULGG) is unclear. Their prognostic value was then investigated, versus conventional factors such as age, neurological status, tumor size, and contrast enhancement (CE). Clinical and anatomical magnetic resonance imaging (MRI) criteria of a cohort of ULGG pts were prospectively evaluated. A dynamic T2*-weighted MR sequence was included to detect high-perfusion areas, using the maximal value of the relative cerebral blood volume (rCBV) estimate, and MVL. Conventional and microvascular characteristics were correlated with progression-free survival (PFS). Among the 46 pts included, the following features were present in 61%, 26%, 67%, and 26%, respectively: age >or=40 years, neurological deficits, tumor size >or=6 cm, and CE. High perfusion value was noted in 30% of cases and MVL in 52%. With median follow-up of 22 months (range 4-46 months), median PFS was 32 months [95% confidence interval (CI) 17-45 months]. On univariate analysis, CE, rCBV, and MVL were significantly correlated with PFS. On multivariate analysis, only CE and MVL were unfavorable factors, with hazard ratio of 3.0 and 7.3 and P value of 0.04 and 0.02, respectively. Different prognostic subgroups were identified, with 2-year PFS of 86%, 57%, and 19% for pts with no MVL, MVL without CE, and MVL with CE, respectively. MVL and CE seem to predict short-term outcome in ULGG pts.

[Postoperative chest: normal imaging features]. / Imagerie du thorax post-opératoire: les aspects normaux.

Chest radiographs and CT are especially useful for the follow-up of patients after lung resection. The purpose of this paper is to illustrate normal postsurgical imaging findings that differ according to the type of surgery (pneumonectomy, lobectomy, segmentectomy and wedge resection). Anatomic changes induced by surgery affect the remaining lung, pleura and chest wall, mediastinum and diaphragm. After pneumonectomy, there is accumulation of fluid in the post pneumonectomy space, progressive chest retraction with mediastinal shift toward the operated side and elevation of the ipsilateral hemidiaphragm. After lobectomy, there is hyperexpansion of the remaining lung, mediastinal shift and intercostal space narrowing. Theses findings are different according to the delay after surgery. Knowledge of the variable imaging features is necessary to detect complications and to provide appropriate follow-up of the primary disease.

Assessment of spinal somatosensory systems with diffusion tensor imaging in syringomyelia.

OBJECTIVE: The use of diffusion tensor imaging with three-dimensional fibre tracking (DTI-FT) was tested for the assessment of spinal sensory tract lesions. The relationships between tract lesions quantified with DTI-FT were systematically examined, and somatosensory dysfunction was assessed with quantitative sensory testing (QST) and laser-evoked potentials (LEP), in patients with syringomyelia. METHODS: 28 patients with cervical syringomyelia and thermosensory impairment of the hands, and 19 healthy volunteers, were studied. A DTI-FT of the spinal cord was performed, focusing on the upper segment (C3-C4) of the syrinx. Three-dimensional DTI-FT parameters (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)) of the full, anterior and posterior spinal cord were individually compared with QST (thermal detection thresholds) and LEP (amplitude, latency and spinothalamic tract (STT) conduction time) of the hands. RESULTS: Patients had a significantly lower FA, but not ADC, than healthy subjects. The mean FA of the full section of the spinal cord was correlated both to sensory deficits (ie, increase in warm (rho = -0.63, p<0.010) and cold thresholds (rho = -0.72; p<0.001 of the hands)) and to changes in LEP parameters, in particular STT conduction time (rho = -0.75; p<0.010). Correlations between FA and the clinical and electrophysiological measures were higher in the anterior area (where the spinothalamic tracts are located) than in the posterior area of the spinal cord. CONCLUSIONS: The data indicate that diffusion tensor imaging with 3D-fibre tracking is a new imaging method suitable for the objective and quantitative anatomical assessment of spinal somatosensory system dysfunction.