Intramedullary spinal epidermoid cysts are benign ectopic embryological growths with reported incidence of less than 1% of intramedullary tumors. In this case we report an unusual cervical intramedullary epidermid with liquid contents. A 40-year-old patient presented with progressive weakness of all four limbs of four months duration, bowel and bladder disturbances of two days duration, pain and paresthesias in all four limbs. Magnetic resonance imaging (MRI) revealed a well defined intramedullary lesion extending from C2-C3 level with widening of the cord. The lesion was hypointense on T1W images, hyperintense on T2W and fluid attenuation and inversion recovery images with thin rim of enhancement after contrast administration. Histopathological examination of the excised specimen revealed epidermal lining and keratinous material features of an epidermoid cyst. As in present case, rarely epidermoid cyst can have clear contents, and an MRI finding can closely mimic the features of arachnoid cyst, findings not classical and is different than described in literature.

The educational objectives for this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of the role of imaging in the evaluation of petrous apex lesions.

Intramedullary epidermoid cysts of the spinal cord are rare tumors, especially those not associated with spinal dysraphism. About 50 cases have been reported in the literature. Of these, only seven cases have had magnetic resonance imaging (MRI) studies. We report two cases of spinal intramedullary epidermoid cysts with MR imaging. Both were not associated with spina bifida. In one patient, the tumor was located at D4 vertebral level; while in the other, within the conus medullaris. The clinical features, MRI characteristics and surgical treatment of intramedullary epidermoid cyst are presented with relevant review of the literature.

Intraspinal dermoid and epidermoid tumors are two histopathological subtypes of cutaneous inclusion tumors of the spine. This classification is based on obsolete embryological knowledge. In fact, according to current embryology, both tumor types consist of ectodermal derivatives. Therefore, we hypothesized that dermoid and epidermoid tumors do not differ in clinical practice. To explore this hypothesis, we studied the clinical, radiological and intraoperative findings of 18 patients, and related these findings to the histopathological characteristics of the tumor. No differences were found between dermoid and epidermoid tumors regarding clinical presentation, radiological examination and outcome, while intraoperative diagnosis by the surgeon correlated with the histopathological diagnosis in only 8 of 18 cases. Therefore, the histopathological difference between intraspinal dermoid and epidermoid tumors is not important in clinical practice and should be avoided. A new nomenclature is proposed in which both tumor types are referred to as 'spinal cutaneous inclusion tumors'.

Spinal intradural arachnoid cysts (ACs) are found frequently in the thoracic region, and often extend over four or five vertebral levels. We present a 28-year-old patient who had a giant thoracic congenital intradural extramedullary AC (T1-T12) with a 10-month history of pain, paresthesia, paraparesis and gait ataxia. A T3 to T6 laminectomy was performed. After durotomy, the posterior wall of the AC was visualized compressing the spinal cord. We resected the cyst wall as widely as possible and connected the cyst to the subarachnoid space using a catheter. There were no postoperative complications. At 1-year follow-up, the patient presented with no motor deficits or pain, and had experienced progressive resolution of the gait ataxia. The treatment of giant intradural extramedullary ACs, especially for those that cannot be totally excised, should include generous fenestration and the insertion of a cyst-subarachnoid shunt.

Anorectal malformations (ARMs) are associated with a variety of spinal dysraphisms, of which clinical impact is often underestimated. A 6-year-old girl, with a history of rectovaginal fistula, presented with gait disturbance, asthenia, and worsening of fecal incontinence. The spinal magnetic resonance imaging (MRI) at 12 months of age had revealed a tethered cord and a little intradural lipoma. Within the lipoma, a small cystic lesion, interpreted as a cerebrospinal fluid (CSF)-filled loculation, was also described. A consecutive MRI showed a marked increase in size of the CSF-like cyst that was clearly hyperintense on diffusion-weighted imaging (DWI) and presented reduced apparent diffusion coefficient values (855 +/- 109 s/mm(2)), not compatible with CSF values. This lesion, interpreted as an (epi)dermoid cyst, was removed and histologically confirmed; the spinal cord was untethered. The child's lower limb motor deficit resolved rapidly after surgery, and the fecal incontinence slowly returned to the previous bowel habit. There is a growing interest in recognizing and defining spinal dysraphism in ARM patients because some abnormalities may carry severe clinical consequences. For this purpose, a standardized MR protocol is required, in which DWI plays a pivotal role to disclose associated dysembriogenetic lesions, in particular when a CSF loculation is detected.

PURPOSE Sacral bone remodelling with abnormal dilatation of intervertebral foramina is usually associated with Tarlov cysts but can be caused by slow-growth lesions, which also may present cerebrospinal-fluid (CSF)-like signal or density. We describe three patients with a similar history of lower back pain presenting CSF-like density/signal lesions with extensive sacral bone remodelling who were affected by a Tarlov cyst, an epidermoid cyst and a giant neurofibroma, respectively. MATERIALS AND METHODS Magnetic resonance imaging (MRI) studies were performed with 1.0-T magnet; axial and sagittal pre- and postcontrast T1-and T2-weighted images were obtained. Moreover, axial and sagittal diffusion-weighted (DWI) echoplanar images were produced, and corresponding apparent diffusion coefficient (ADC) values were calculated. ADC values were measured within the lesions on axial images. RESULTS All lesions presented a CSF-like signal on conventional MRI. The Tarlov cyst was hypointense on DWI with high ADC values (2,793 s/mm(2)+/-137). The epidermoid cyst proved to be markedly hyperintense on DWI, with reduced ADC values (855 s/mm(2)+/-109). The neurofibroma was isointense on DWI, with ADC values not compatible with CSF (1,467 s/mm(2)+/-130). CONCLUSIONS DWI and ADC values seem to be able to clearly differentiate Tarlov cysts from slow-growth lesions, allowing for adequate treatment.

PURPOSE To prospectively evaluate effect of functional magnetic resonance (MR) imaging on diagnostic work-up and treatment planning in patients with seizure disorders who are candidates for surgical treatment. MATERIALS AND METHODS Institutional review board approval was obtained; informed consent was obtained either from the patient or the parent or guardian in all patients. This study was conducted with Health Insurance Portability and Accountability Act compliance. Sixty consecutively enrolled patients (33 males, 27 females; mean age, 15.8 years +/- 8.7 [standard deviation]; range, 6.8-44.2 years) were prospectively examined. Forty-five (75%) patients were right handed, nine (15%) were left handed, and six (10%) had indeterminate hand dominance. Prospective questionnaires were used to evaluate diagnostic work-up, counseling, and treatment plans of the seizure team before and after functional MR imaging. Confidence level scales were used to determine effect of functional MR imaging on diagnostic and therapeutic thinking. Paired t test and 95% confidence interval analyses were performed. RESULTS In 53 patients, language mapping was performed; in 33, motor mapping; and in seven, visual mapping. The study revealed change in anatomic location or lateralization of language-receptive (Wernicke)(28% of patients) and language-expressive (Broca)(21% of patients) areas. Statistically significant increases were found in confidence levels after functional MR imaging in regard to motor and visual cortical function evaluation. In 35 (58%) of 60 patients, the seizure team thought that functional MR imaging results altered patient and family counseling. In 38 (63%) of 60 patients, functional MR imaging results helped to avoid further studies, including Wada test. In 31 (52%) and 25 (42%) of 60 patients, intraoperative mapping and surgical plans, respectively, were altered because of functional MR imaging results. In five (8%) patients, two-stage surgery with extra-operative direct electrical stimulation mapping was averted, and resection was accomplished in one stage. In four (7%) patients, extent of surgical resection was altered because eloquent areas were identified close to seizure focus. CONCLUSION Functional MR imaging results influenced diagnostic and therapeutic decision making of the seizure team; results indicated language dominance changed, confidence level in identification of critical brain function areas increased, patient and family counseling were altered, and intraoperative mapping and surgical approach were altered.

This article reviews the scientific evidence behind the diagnostic tools available for the appropriate workup and management of patients with occult spinal dysraphism (OSD). The diagnostic tools include the use of detailed history and physical examination, plain films, ultrasound, MR imaging, and neurophysiologic tests. In addition, the article discusses the epidemiology of the most common causes of OSD in children, which will allow physicians caring for children to develop a pretest probability of disease and make a more educated decision as to when additional diagnostic testing is required.

Ten pediatric medulloblastoma patients were analyzed for DNA content, cell cycle, expression of drug resistance, apoptosis, cell proliferation, and N-myc genes to determine their prognostic significance. Medulloblastoma patients with progressive disease had fourth ventricle foraminal extension and larger tumors in the imaging studies. Patients with aneuploid tumors responded well to treatment regimens as compared with those with diploid tumors. Cell cycle analysis showed that the patients with progressive disease had a high S-phase fraction in the tumor cell population as compared with patients with favorable response to treatment. The correlation coefficients between Bcl-2 and MRP, Bcl-2 and Bax, p53 and p21, as well as Ki67 and PCNA were positive and significant, indicating their possible coregulated expression. The relationship between these markers indicates their relative and cumulative effect on cellular drug resistance, apoptosis, and/or cell proliferation in pediatric medulloblastomas.

Transarterial radioembolisation with yttrium-90 (TARE-Y90), a catheter-directed therapy, has been used extensively in adults to treat primary and secondary hepatic malignancies. To our knowledge, the use of this palliative technique has not been described in children. We present two children with unresectable hepatocellular carcinoma (HCC) treated with TARE-Y90.

Background/Aims: This study evaluates endoscopic choroid plexus coagulation, in conjunction with third ventriculostomy when technically feasible, as a strategy to treat patients with hydranencephaly or hydrocephalus with a minimal cortical mantle. Methods: We retrospectively reviewed patients with hydranencephaly (n = 4) or hydrocephalus with the cortical mantle <1 cm in maximal thickness (n = 4) who underwent endoscopic choroid plexus coagulation from 2007 to 2010. Endoscopic third ventriculostomy was performed simultaneously when technically feasible (in 3 of 8 patients). Endoscopic management was considered successful if a shunt was not subsequently required. Results: Endoscopic management was successful in 4 of 8 patients (50%) who did not require a shunt over a median follow-up period of 15 months (range 2.5-24). Four patients (50%) failed endoscopic management and required a shunt 1 month to 11 weeks after endoscopic surgery. One patient died 4 days after shunt placement due to pneumonia and renal failure. Three of 4 patients who had a successful endoscopic procedure ultimately died of causes that were likely unrelated to hydrocephalus (pneumonia in 2 patients and sudden infant death syndrome in 1 patient). Besides failure to control hydrocephalus adequately in 4 patients, there were no additional complications noted after endoscopic surgeries. Conclusion: Endoscopic choroid plexus coagulation can enable some infants with hydranencephaly or massive hydrocephalus to avoid a ventriculoperitoneal shunt.

PURPOSE To describe a combined transcranial-orbital approach for en bloc resection of optic nerve gliomas with preservation of the annulus of Zinn that minimizes recurrence and prevents postoperative paralytic ptosis. METHODS Design: A retrospective, noncomparative, interventional case series. Study Population: All patients who underwent optic nerve glioma resections using this technique with the authors between 1994 and 2010. PROCEDURE A transcranial-orbital approach is used to resect the intracranial segment of the optic nerve glioma from 2 mm anterior to the chiasm to the posterior extent of annulus of Zinn. The proximal transected edge of the nerve is examined intraoperatively for tumor margin clearance. Through a superior orbitotomy exposure, the entire retrobulbar segment of the tumor is transected from the globe to the annulus of Zinn. A simulation of the procedure in a cadaver and en bloc resection of the orbital apex are performed to demonstrate the subdural plane of dissection within the annulus of Zinn. MAIN OUTCOME MEASURES Postoperative outcome measures include: health of the ipsilateral globe, paralytic ptosis, postoperative complications, and tumor recurrence. RESULTS Eleven patients underwent resection of optic nerve gliomas using this technique. No patients had tumor recurrence or developed postoperative paralytic ptosis. CONCLUSIONS The combined transcranial-orbital approach with preservation of the annulus of Zinn is a safe and effective way to remove optic nerve gliomas and ensure tumor clearance while avoiding paralytic ptosis.

PURPOSE Medically refractory epilepsy caused by cortical tubers resulting from tuberous sclerosis complex (TSC) often requires surgical intervention. The locations of cortical tubers generally are determined by preoperative magnetic resonance imaging (MRI). In this pilot study, we explored the feasibility of using the optical characteristics of cortical tubers as a potential means to guide their resection intraoperatively. METHODS Optical characteristics of normal cortex and cortical tubers were measured intraoperatively using diffuse reflectance spectroscopy in three children undergoing epilepsy surgery for drug-resistant seizures. Unique diffuse reflectance spectroscopic features of cortical tubers were identified and their physiologic associations determined. KEY FINDINGS Diffuse reflectance spectra revealed several features that distinguish cortical tubers from normal cortex. In tubers, diffuse reflectance intensities at oxy- and deoxyhemoglobin isobestic points, like 500, 530, and 570 nm, were consistently higher than those in normal cortex. According to the profile of diffuse reflectance spectra from 520-580 nm, hemoglobin oxygenation in tubers often was lower than in normal cortex. SIGNIFICANCE Albeit preliminary, our findings suggest that the optical characteristics of cortical tubers differ from intervening normal cortex, likely reflecting the lower cerebral blood volumes and reduced hemoglobin oxygenation of cortical tubers. The results of this study can be used to design biomedical instruments that aid tuberectomies.

BACKGROUND AND IMPORTANCE -: Cavernous malformations of the cranial nerves are exceedingly rare. The classic radiographic appearance of cavernous malformations may not be obvious when located in a cranial nerve. CLINICAL PRESENTATION -: We present two cases of acute oculomotor paresis due to cavernous malformations of the oculomotor nerve that were mistaken for a thrombosed posterior communicating artery aneurysm on MRI, MRA and digital subtraction angiography. Both patients underwent a craniotomy with exploration of the lesion. Both cavernous malformations were completely resected while maintaining the integrity of the third cranial nerve. One patient experienced complete resolution of the oculomotor palsy. CONCLUSION -: Although rare, cavernous malformations should be included in the differential diagnosis of a partially thrombosed posterior communicating artery aneurysm. Exploration and complete lesional resection are possible with improvement of the cranial nerve function.

OBJECT The natural history of untreated Chiari malformation Type I (CM-I) is poorly defined. The object of this study was to investigate outcomes in pediatric patients with CM-I who were followed up without surgical intervention. METHODS The authors retrospectively reviewed 124 cases involving patients with CM-I who presented between July 1999 and July 2008 and were followed up without surgery. The patients ranged in age from 0.9 to 19.8 years (mean 7 years). The duration of follow-up ranged from 1.0 to 8.6 years (mean 2.83 years). Imaging findings, symptoms, and findings on neurological examinations were noted at presentation and for the duration of follow-up. RESULTS The mean extent of tonsillar herniation at presentation was 8.35 mm (range 5-22 mm). Seven patients had a syrinx at presentation. The syrinx size did not change in these patients on follow-up imaging studies. No new syrinxes developed in the remaining patients who underwent subsequent imaging. The total number of patients with presenting symptoms was 81. Of those 81 patients, 67 demonstrated symptoms that were not typical of CM-I. Of the 14 patients with symptoms attributed to CM-I, 9 had symptoms that were not severe or frequent enough to warrant surgery, and surgery was recommended in the remaining 5 patients. Chiari malformation Type I was also diagnosed in 43 asymptomatic patients who had imaging studies performed for various reasons. No new neurological deficits were noted in any patient for the duration of follow-up. CONCLUSIONS The majority of patients with CM-I who are followed up without surgery do not progress clinically or radiologically. Longer follow-up of this cohort will be required to determine if symptoms or new neurological findings develop over the course of many years.

Advanced medical treatment options have improved pediatric survival but often require invasive vascular procedures or venous access. These procedures increase the risk for thromboembolism in children, and there has been a corresponding increase in the reported incidence of deep venous thrombosis and postthrombotic syndrome in the pediatric population. Percutaneous venous interventions using catheter-directed therapy (CDT), like mechanical thrombectomy and infusion thrombolysis, have been used much less frequently in children, even though they have shown good results in adults. A multidisciplinary team including pediatric hematology, interventional radiology, and intensive care unit is suggested for management of venous thrombosis in children. Indications and contraindications for CDT in children are similar to adults. Mechanical thrombectomy and infusion thrombolysis are some of the more commonly performed treatments. CDT in children requires adapting to patient size and locally available equipment. Ultrasound guidance for access,"cork" technique, appropriate dosing of tissue plasminogen activator for infusion/pharmacomechanical thrombolysis, and simultaneous administration of heparin, plasminogen (fresh frozen plasma), and deficient coagulation factors are some of the important variations of CDT technique in children. Postprocedure monitoring is very important for successful thrombolysis. Retrievable inferior vena cava filters are increasingly being used in children as well, for prophylaxis against pulmonary embolism (PE) if there is a significant risk of PE with/without contraindications to anticoagulation.

Intracranial endoscopy in the treatment of hydrocephalus, arachnoid cysts, or brain tumors has gained wide acceptance, but the use of endoscopy for intradural navigation in the pediatric spine has received much less attention. The aim of the authors' present study was to analyze their experience in using spinal endoscopy to treat various pathologies of the spinal canal. The authors performed a retrospective review of intradural spinal endoscopic cases at their institution. They describe 4 representative cases, including an arachnoid cyst, intrinsic spinal cord tumor, holocord syrinx, and split cord malformation. Intradural spinal endoscopy was useful in treating the aforementioned lesions. It resulted in a more limited laminectomy and myelotomy, and it assisted in identifying a residual spinal cord tumor. It was also useful in the fenestration of a multilevel arachnoid cyst and in confirming communication of fluid spaces in the setting of a complex holocord syrinx. Endoscopy aided in the visualization of the spinal cord to ensure the absence of tethering in the case of a long-length Type II split spinal cord malformation. Conclusions Based on their experience, the authors found intradural endoscopy to be a useful surgical adjunct and one that helped to decrease morbidity through reduced laminectomy and myelotomy. With advances in technology, the authors believe that intradural endoscopy will begin to be used by more neurosurgeons for treating diseases of this anatomical region.

OBJECTIVE To demonstrate the role of magnetic resonance imaging (MRI) in determining the treatment protocol for hydatid disease of the spine. DESIGN Case report; literature review. FINDINGS Diffusion-weighted MRI can help differentiate complicated infected hydatidosis from abscesses, epidermoid cysts from arachnoid cysts, and benign from malignant vertebral compression fractures. It is also helpful in differentiating between abscesses and necrotic tumors. CONCLUSION Diffusion-weighted MRI can help differentiate between infections requiring immediate surgery and those that can be treated medically with antihelmintic treatment.

Early diagnosis and prompt initiation of adequate treatment are essential for clinical outcome in ISCA. We report a case in which DWI provided a more specific diagnosis than conventional MR imaging and allowed differentiation of a ring-enhancing lesion from intramedullary tumor. Diagnosis was proved by PCR from CSF (Streptococcus intermedius). Adequate antibiotic treatment was immediately initiated, and the patient recovered completely.

Symptomatic intramedullary arachnoid cysts are rare, especially in children; these lesions are rarely described as a cause of spinal cord compression in this age group. The authors report on an 18-month-old boy who experienced a sudden loss of his ability to stand and walk due to a paraparesis. Magnetic resonance imaging of the spine exhibited a cystic intramedullary lesion at the level of T5-6. A hemilaminectomy was performed, and after myelotomy the cystic lesion was decompressed by fenestration to the subarachnoid space. The histopathological examination verified the diagnosis of an arachnoid cyst. In the postoperative course the boy experienced complete resolution of the initial paraparesis.

Imaging of the spine is a fundamental part of assessment of paraparesis. Since the advent of MRI the indications for myelograms have diminished. However, a myelogram, although an invasive test, should still be considered a useful investigation for localising lesions in the spinal cord and for identifying rare causes of myelopathy. This case illustrates how a CT myelogram identified an arachnoid cyst, which is a potentially treatable cause of paraparesis.

BACKGROUND The differential diagnosis of various intracranial cystic lesions is sometimes difficult on the basis of CT or MRI findings. Our objective was to evaluate (1)H MRS and DWI in the differential diagnosis of these lesions and in comparison with conventional MRI. METHODS Fifty patients with intracranial cystic lesions (21 pyogenic abscesses, 23 tumor cysts, 3 epidermoid cysts, and 3 arachnoid cysts) were evaluated with conventional MRI, DWI, and in vivo (1)H MRS. Preoperative diagnosis of the lesions was based on the results of DWI and in vivo MRS. All DWI and (1)H MRS studies were performed with a clinical 1.5-T system. The DWI was performed using single-shot spin-echo echo-planar pulse sequence with b = 1000 s/mm(2). The ADC value was measured. Diagnostic accuracy of conventional MRI, DWI, and in vivo (1)H MRS was calculated with respect to a final diagnosis of brain abscess vs nonabscess cystic tumor. RESULTS Lactate and cytosolic amino acids with/without succinate, acetate, and alanine were observed in 18 of 21 cases of abscesses on MRS. In 3 cases of epidermoid cysts, lactate was observed and could be differentiated from 3 cases of arachnoid cysts, which showed only minimal lactate. Only lactate was seen in 14 of 23 patients with tumor cysts, whereas both lipid/lactate and choline were visible in 9 patients with tumor cysts. Increased signal was seen in 20 of 21 patients with abscesses and 3 patients with epidermoid cysts on DWI. Decreased signal was observed in 22 of 23 patients with tumor cysts and 3 patients with arachnoid cyst on DWI. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of conventional MRI for the differentiation of brain abscess from nonabscess cystic tumor were 61.4%, 61.9%, 60.9%, 59.1%, and 63.6%, respectively, whereas they were 93.2%, 85.7%, 100%, 100%, and 88.5% with MRS; 95.5%, 95.2%, 95.7%, 95.2%, and 95.7% with DWI; and 97.7%, 95.2%, 100%, 100%, and 95.8% with MRS and DWI. Magnetic resonance imaging, when combined with in vivo MRS and DWI, accurately predicted the diagnosis in 47 (94%) of 50 and 48 (96%) of 50 of the cases, respectively. CONCLUSIONS Proton MRS and DWI are useful as additional diagnostic modalities in differentiating intracranial cystic lesions. Combination of DWI with calculated ADC values and metabolite spectrum acquired by MRS add more information to MRI in the differentiation of intracranial cystic mass lesions.

BACKGROUND: Extradural arachnoid cysts in the spine are uncommon causes of spinal cord compression in the pediatric population that are thought to arise from congenital defects in the dura mater. Most reports describe such cysts as communicating with the intrathecal subarachnoid space through a small defect in the dura. Excision of the cyst with obliteration of the communicating dural defect is the mainstay of treatment in symptomatic patients. Solitary extradural arachnoid cysts have been reported in several studies, but multiple extradural arachnoid cysts are very rarely reported in children. MATERIALS AND METHODS: The authors report a case of multiple extradural spinal arachnoid cysts in a 14-year-old boy who presented progressive lower extremity weakness, myelopathy, and severe gait ataxia. Magnetic resonance (MR) of the spine demonstrated four extradural arachnoid cysts extending from T-1 to T-9. The patient underwent a thoracic laminoplasty for en bloc resection of the spinal extradural arachnoid cysts. Postoperatively, the patient's motor strength and ambulation improved immediately. CONCLUSIONS: Multiple spinal extradural arachnoid cysts are rarely reported in the literature. Excision of the cysts at the spinal cord level leads to a favorable outcome.

Symptomatic multiple extradural arachnoid cysts of the spine are extremely uncommon in children and have only rarely been reported. The authors report a case of multiple extradural spinal arachnoid cysts in a 14-year-old child who presented with signs of spinal cord compression. The disease affected the thoracic spine and extended from T-5 to T-10 with an underlying defect in the dura of the spinal canal that was predisposed to the formation of cysts. The authors describe the imaging examination, surgical planning, and surgical technique, and they review the literature. They also discuss the possible mechanisms of cyst formation.

Juxtafacet cysts are lesions that are associated with spinal facet joints. Although these lesions are frequently noted as incidental findings on imaging studies of the spine, they may produce symptoms in some patients. Juxtafacet cysts can mimic herniated discs, resulting in symptoms from focal nerve root and/or spinal cord compression. Some of these lesions are associated with spinal instability, and patients may require spinal fusion to address this underlying disorder. Conservative therapy for symptomatic lesions is often unsuccessful, although there are reports of spontaneous resolution of these cysts as well as the symptoms associated with them. Surgical therapy should be focused on decompression of the lesions causing nerve root compression and the accompanying symptoms, while recognizing that instability requiring fusion may be present in some but not all cases.

Multiple sclerosis is now recognized as more than simply a disease of inflammation and demyelination in the brain and spinal cord. Conventional MRI has been established as the most important paraclinical tool in the diagnostic assessment of patients with suspected MS, and in the monitoring of treatment efficacy in clinical trials, at least in relapsing disease. Magnetization-transfer, diffusion-weighted MRI, 1H-MRS, and fMRI improve our ability to quantify the pathological changes in MS in vivo. Although we have gained some insight into the disease and are starting to uncover some of the structural and physiological substrates for the disability that develops in MS patients, we are far from understanding what causes MS and how to prevent its progression. Imaging can be used as a tool to better understand the pathophysiology of MS and ultimately improve on the treatment of MS.