Preliminary experience of CT imaging of the ischaemic brain penumbra through spectral processing of multiphasic CTA datasets

To assess ischaemic penumbra through the post-processing of the spectral multiphasic CT Angiography (mCTA) data in acute ischaemic stroke (AIS) patients. Thirty one consecutive patients strongly suspected of severe Middle Cerebral Artery AIS presenting less than 6 h after onset of symptoms or with unknown time of onset of symptoms underwent a standardized CT protocol in spectral mode including Non Contrast CT, mCTA, and Perfusion CT (CTP) on a dual-layer MDCT system. Areas disclosing delayed enhancement on iodine density (ID) maps were highlighted by subtraction of the serial mCTA datasets. Two neuroradiologists independently rated the correspondence between delayed enhancing areas at mCTA and the penumbral/infarcted areas delineated by two validated CTP applications using a 5-levels scoring scale. Interobserver agreement between observers was evaluated by kappa statistics. Dose delivery was recorded for each acquisition. Averaged correspondence score between penumbra delineation using subtracted mCTA-derived ID maps and CTP ones was 2.76 for one application and 2.9 for the other with best interobserver agreement kappa value at 0.59. All 6 stroke mimics out of the 31 patients' cohort were correctly identified. Average dose delivery was 7.55 mSv for the whole procedure of which CTP accounted for 39.7%. Post-processing of spectral mCTA data could allow clinically relevant assessment of the presence or absence of ischaemic penumbra in AIS-suspected patients if results of this proof-of-concept study should be confirmed in larger patients'series.

Ectopic sphenoidal ACTH-secreting adenoma revealed by 11C Methionine PET scan: case report

BACKGROUND

Ectopic ACTH pituitary adenomas (EAPA), located outside the sella turcica and deriving from cellular remnants of Rathke's pouch are a very rare cause of Cushing's syndrome (CS). The diagnosis is often difficult and delayed, even after comprehensive work-up. To our knowledge, we report for the first time an ectopic corticotroph tumor of the posterior wall of the sphenoid sinus, leading to false positive results of bilateral inferior petrosal sinus sampling (BIPPS) and which was finally localized by a co-registered¹¹ C Methionine PET/MR imaging.

CASE PRESENTATION

A 48-year-old woman was referred for a high clinical suspicion of ACTH-dependent CS. Biological testing comprising low dose dexamethasone suppression and CRH stimulation tests were indicative of pituitary Cushing's disease, but comprehensive pituitary MRI did not reveal any pituitary adenoma. BIPSS confirmed however a central origin of ACTH secretion (central-to-peripheral ACTH ratio > 100) and revealed a significant right-to-left gradient (6.2), leading to a first right-sided exploratory hypophysectomy, that did not cure the patient. BIPSS images were reviewed and revealed preferential drainage of the left pituitary to the right petrosal sinus, leading us to a left sided exploratory hypophysectomy, which was again unsuccessful. A¹¹ C Methionine PET/MRI was performed and revealed a hypermetabolic lesion adjacent to the posterior wall of the sphenoidal sinus. After surgical resection, this polypoid mass was identified as an ectopic ATCH-secreting pituitary adenoma expressing ACTH and T-Pit and complete remission of hypercortisolism was observed.

CONCLUSIONS

In conclusion, we report a case of ACTH-dependent Cushing's syndrome, caused by an ectopic corticotroph adenoma located in the sphenoidal sinus, which perfectly mimicked the biological features of a classical pituitary ACTH adenoma on a comprehensive hormonal evaluation including BIPPS, and the features of a benign naso-sinusal polyp at MRI. We report for the first time a key role of¹¹ C Methionine PET co-registered to high resolution MRI for localizing ectopic adenomas, efficiently guiding surgical removal and leading to complete remission of hypercortisolism.

Conservative management of complicated Rathke's cleft cyst mimicking pituitary apoplexy

Summary

Complicated Rathke's cleft cyst (RCC) is a rare occurrence of symptomatic bleeding or growth of a previously asymptomatic (and often undiagnosed) intrasellar cyst derived from remnants of Rathke's pouch, situated on the midline between the adeno- and neurohypophysis. Symptoms may be identical to those of pituitary apoplexy: acute onset of headache, hypopituitarism, and neurological disturbances. Both syndromes may also exhibit a similar appearance of a large haemorrhagic sellar mass at initial radiological evaluation. We report on two patients who presented with headache and complete hypopituitarism. Based on the initial MRI, they were first diagnosed with pituitary apoplexy but managed conservatively with hormone therapy alone because of the absence of severe visual or neurological threat. Upon follow-up at 4 months, clinical evolution was good in both patients but their pituitary mass had not reduced in size and, after careful radiologic reviewing, was more indicative of a large midline complicated RCC. In conclusion, the diagnosis of complicated RCC is challenging because it can mimic pituitary apoplexy clinically, biologically, and radiologically. Clinicians should distinguish between the two entities using specific radiological signs or evolution of the mass at MRI if the patient does not undergo surgery. To our knowledge, we report conservative management of this rare condition for the first time, though it seems appropriate in the absence of neurological compromise or visual compression. Long-term follow-up is however mandatory.

Learning points

Complicated Rathke's cleft cyst can mimic pituitary apoplexy, presenting with sudden onset of headache, hypopituitarism, and visual and neurological compromise in the most severe cases. At diagnosis, pituitary MRI may not be able to differentiate between the two entities, showing a large haemorrhagic mass inside the sella, with little or no normal pituitary tissue visible. Patients are often diagnosed with apoplexy at this stage and may undergo pituitary surgery. When surgery has not been performed initially in these patients, repeat imaging at 3-6 months is unchanged and does not show the expected involution usually seen after adenoma apoplexy. Conservative management with hormonal replacement seems a valid option in the absence of visual or neurological deficits that would require trans-sphenoidal surgery.

Functional Prognostic value of optical coherence tomography in optic chiasmal decompression: A preliminary study

PURPOSE

To assess the predictive value for functional recovery of Ganglion Cell Complex Layer (GCC) and Retinal Nerve Fiber Layer (RNFL) measurements obtained by Optical Coherence Tomography (OCT) in patients undergoing chiasmal decompression and to define potential OCT thresholds for visual recovery.

METHODS

We measured preoperative GCC and RNFL thickness in patients with a sellar and/or perisellar tumor compressing the optic chiasm. Visual recovery was defined as recovery of mean deviation (MD) and pattern standard deviation (PSD) using Humphrey visual field testing after 12 successful decompressions (24 eyes). Receiver operating characteristic curve (ROC) analysis was used to identify the best thresholds.

RESULTS

Robust global and focal OCT thresholds were found. Superior GCC≥63μm had the best functional prognostic value (AUC=1) for visual improvement. Mean GCC ≥ 67μm and mean RNFL≥75μm also had excellent predictive values (AUC>0.9).

CONCLUSION

In this preliminary study, significant preoperative OCT thresholds for early visual recovery after chiasmal decompression were identified, mainly regarding GCC measurements. Further studies on larger cohorts with closely scheduled follow-up could refine our results.

Intracranial brain parenchymal spread of mucormycosis through olfactory tract: a diffusion-weighted imaging-based concept

Mucormycosis is an opportunistic fungal infection involving among others the paranasal sinuses, nasal fossa and brain parenchyma. Mucor can invade the brain parenchyma by either contiguous spread from the paranasal sinuses or through vascular invasion. We report a case of fatal rhino-cerebral mucormycosis in whom cytotoxic edema at magnetic resonance diffusion-weighted imaging was symmetrically restricted to both neocortical and paleocortical primary areas of olfactory projection at earliest phase of the disease process. Shortly later tissue damage extended into the whole brain. This undescribed observation raised the hypothesis of preferential way of brain invasion by Mucor through the olfactory tract.

T2-weighted magnetic resonance imaging characterization of prolactinomas and association with their response to dopamine agonists

PURPOSE

Recent work supports the use of T2-weighted MRI intensity as a tool for treatment stratification in acromegaly. Our study aimed to establish if the pattern of T2 intensity could be a predictor of hormonal and/or tumoral response to dopamine agonists (DAs) in prolactinomas.

METHODS

This was a retrospective study performed in two academic centers. We characterized the magnetic resonance T2-weighted aspect of prolactinomas (signal intensity and homogeneity in the whole tumors) before DA therapy and correlated this pattern to the prolactin (PRL) concentration at diagnosis and to hormonal and tumoral responses after 1 year of medical treatment. We separately analyzed a subgroup of prolactinomas visually very bright in more than 50% of the surface ("cystic" tumors).

RESULTS

Out of 70 prolactinomas, 80% were T2 hyperintense and 40% were heterogeneous. At diagnosis, heterogeneous prolactinomas were more frequent in men (68% vs. 28.9%, p ≤ 0.011), larger (median area 304.5 mm² vs. 56.5 mm², p ≤ 0.021), taller (mean height 18.6 mm vs. 9.9 mm, p < 0.001), more secreting (median PRL ULN_area 23 µg/L/cm² vs. 12.6 µg/L/cm², p ≤ 0.032) and had poorer hormonal response to DA as compared with homogeneous prolactinomas. "Cystic" tumors were diagnosed almost exclusively in women and secreted less prolactin, but showed similar hormonal and tumoral response as "non-cystic" tumors. In homogeneous prolactinomas, the T2-weighted intensity ratio was correlated to prolactin secretion, although not significantly, and did not predict hormonal and tumoral response to DA.

CONCLUSIONS

Our study confirms that hypo/isointense prolactinoma is a rare finding and suggests for the first time that the heterogeneity of prolactinoma T2 signal at diagnosis might be correlated with a different clinical behavior and could be used as a negative predictor factor of hormonal response to DA.

Partial cauda equina syndrome after an uneventful minimally invasive microdiscectomy in a patient with Crohn's disease

Cauda equina syndrome is a serious condition resulting from dysfunction of the lumbosacral nerve roots and characterized by impairment of bladder, bowel, sexual and lower limb functions. We report the case of a 48-year-old woman who had Crohn's disease for more than twenty years. The patient was undergoing immunotherapy with infliximab and developed a partial cauda equina syndrome after an uneventful minimally invasive microdiscectomy (L₅-S₁) that completely cured her sciatica. A postoperative magnetic resonance imaging examination showed root clumping but no compressive lesion. We discuss a possible relationship between the cauda equina syndrome and the patient's active Crohn's disease, treatment and surgery.

Post-injury smell disorders

Post-injury smell disorders.

PROBLEMS/OBJECTIVES

Head trauma is the third most common aetioiogy of post-traumatic olfactory loss (PTOL). This literature review aims to report the existing knowledge surrounding this issue, exploring the current understanding of the inducing pathogenesis and the assessment and management standards from the early phases to longer-term considerations.

METHODOLOGY

Literature search and appraisal in PubMed on the following themes directly associated with PTOL: olfactory disorders, trauma, pathogenesis, examination, recovery and treatment.

RESULTS

Scientific evidence was mainly available for epidemiology and exploration tools in cases suffering from PTOL. The current research into obj6ctive batteries of olfactory tests is promising.

CONCLUSIONS

This paper highlights the importance of an adequate assessment of PTOL for an early start in olfactory training.

Primary undifferentiated carcinoma of the trachea

BACKGROUND

Primary undifferentiated or lymphoepithelial carcinoma mainly occurs in the nasopharynx. Tracheal localization is exceedingly rare. To the best of our knowledge, only four cases have been reported previously, all in Asian patients.

CASE REPORT

A 61-year-old male European patient presented with hemoptysis and cough for several months. The workup revealed a primary tracheal tumor without regional or distant metastasis. The patient was treated with tracheal resection followed by end-to-end reconstruction. Pathologic analysis of the tumor, including immunohistochemistry, confirmed the diagnosis of lymphoepithelioma-like carcinoma. Testing for Epstein-Barr virus by hybridization in situ was massively positive. With a follow-up at 15 months, the patient is alive and free of disease.

CONCLUSION

We report the first case of lymphoepithelioma-like carcinoma in the trachea in the European population. Treatment possibilities are discussed. They should be based on each patient's clinical presentation and the results of their preoperative workup.

Tumour response and safety of cetuximab in a window pre-operative study in patients with squamous cell carcinoma of the head and neck

BACKGROUND

To investigate the safety and activity of cetuximab in the pre-operative treatment of squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Cetuximab was administered for 2 weeks before surgery to 33 treatment-naïve patients selected for primary surgical treatment. Tumour biopsies, 2-[fluorine-18]-fluoro-2-deoxy-d-glucose positron emission tomography ((18)FDG-PET) and imaging were carried out at baseline and before surgery. The primary aim of the study was safety and the secondary aims included metabolical, radiological and pathological tumour response. Five untreated patients were included as controls.

RESULTS

Cetuximab given 24 h before surgery was safe. Ninety percent of patients had (18)FDG-PET partial response (EORTC guideline) in the cetuximab group versus 0% in the control group. Delta maximal standardized uptake values (ΔSUVmax) were correlated with tumour cellularity on the surgical specimens (P < 0.0001). For patients with ΔSUVmax less than -25% or less than -50%, Ki67 was significantly decreased by cetuximab (P = 0.01 and 0.003). Cetuximab induced down-regulation of pEGFR (P = 0.0004) and pERK (P = 0.003).

CONCLUSIONS

Short-course pre-operative administration of cetuximab is safe and shows a high rate of (18)FDG-PET response. (18)FDG-PET response was correlated with residual tumour cellularity suggesting that (18)FDG-PET deserves further investigation as a potential early marker of cetuximab activity in SCCHN.

Pitfalls in preoperative work-up of parotid gland tumours: 10-year series

PROBLEMS/OBJECTIVES

Preoperative fine-needle aspiration cytology (FNAC) and magnetic resonance imaging (MRI) are the two most widely accepted diagnostic techniques used for the assessment of parotid gland tumours. We retrospectively evaluated the ability of FNAC and MRI to predict malignancy in parotid gland tumours.

METHODOLOGY

Over a period of 10 years (2002-2011), parotidectomy for primary parotid gland tumours was performed in a consecutive series of 178 patients. Preoperative MRI was performed in 75% (133/178) of cases, and preoperative FNAC was performed in 70% of cases (124/178). Both modalities were applied in 53% (94/178) of patients. Sensitivity, specificity, and accuracy were analyzed retrospectively for each subgroup of patients.

RESULTS

The sensitivity, specificity, and accuracy for predicting malignancy were 45%, 89%, and 84%, respectively, for FNAC (including only diagnostic cytology), and 40%, 88%, and 81%, respectively, for MRI. In the subgroup of patients who underwent both MRI and FNAC, sensitivity, specificity, and accuracy were 50%, 85%, and 80%, respectively. Preoperative MRI values improved significantly after introduction of diffusion-weighted (DW) acquisition in 2007 (71%, 93%, and 91%, respectively).

CONCLUSIONS

Compared to previously published results, the high number of nondiagnostic smears and the low sensitivity rates in our series were disappointing, In part, this can be explained by the low percentage of malignant tumours and the high number of low-grade tumours among these. We discuss possibilities for improving preoperative performance, such as ultrasound-guided FNAC.

Percutaneous pedicle screw implantation for refractory low back pain: from manual 2D to fully robotic intraoperative 2D/3D fluoroscopy

Many surgical treatments for chronic low back pain that is refractory to medical treatments focus on spine stabilization. One of the main surgical procedures consists of placing an interbody cage with bone grafts associated with pedicle screws [2, 25, 30]. This technique can be performed using different approaches: a large open posterior approach, tubular approaches (minimal open) or percutaneously (minimally invasive percutaneous or MIP) [5, 28]. One of the main difficulties is to precisely locate the screws into the pedicle avoiding especially infero-medial pedicle breaches. This difficulty is even great- er when working percutaneously. This paper focuses on percutaneously placed pedicle screws (PPS), reports the use of a robotic multi-axis 2D/3D fluoros- copy to enhance the accuracy of pedicle screw placement and reviews other strategies and results reported in the literature.

The depth of the olfactory sulcus is an indicator of congenital anosmia

BACKGROUND AND PURPOSE

In congenital anosmia, the OB and OT can be aplastic or hypoplastic. In clinical routine, these are sometimes difficult to assess. We thus wanted to investigate morphologic differences of the OS in patients with IA since birth or early childhood in comparison with controls, to investigate whether there is a depth of OS that is predictive of IA.

MATERIALS AND METHODS

Within the context of a 2-center study, we investigated 36 patients with IA in comparison with 70 controls. MR imaging was performed with a standard quadrature head coil (1.5T; T1- and T2-weighted spin-echo sequences were used on the coronal plane). We assessed the depth of OS in the PPTE.

RESULTS

Looking at the depth of the OS in the PPTE, we found that patients with IA had a significantly smaller OS compared with controls (P < .001). None of the healthy controls exhibited a depth of <8 mm. In patients with IA, 10 had an OS deeper than 8 mm, while 26 had an OS smaller than 8 mm. Thus, a depth of the OS less than 8 mm clearly indicates IA, with a specificity of 1 and a sensitivity of 0.72.

CONCLUSIONS

In IA, the depth of the OS in the PPTE is a useful clinical indicator. Indeed, if it is ≤8 mm, it clearly indicates IA, with a specificity of 1.

[Intramedullary tumours and pseudotumours]

Swelling of the spinal cord and/or enhancement after intravenous gadolinium administration are not always specific features of intramedullary tumour. These may also be seen in association with several diseases of inflammatory, infectious, granulomatous or vascular origin. A tumour is characterized by its sagittal location, axial topography: central, lateral or exophytic, its size and size of the spinal canal, macroscopic components: calcium, fat, methemoglobin, melanin, hemosiderin, vascular pedicle, cystic component, enhancement after intravenous gadolinium administration, effect on the spinal cord tracts and edema. Characteristics: astrocytoma is lateral and infiltrative, ependymoma is central with white matter tract displacement and hemosiderin cap, hemangioblastoma is postero-lateral and shows enhancement with a vascular pedicle, metastases are very edematous or leptomeningeal in location.

Olfactory bulb volume in the clinical assessment of olfactory dysfunction

The olfactory bulb collects the sensory afferents of the olfactory receptor cells located in the olfactory neuroepithelium. The olfactory bulb ends with the olfactory tract and is closely related to the olfactory sulcus of the frontal lobe. Many studies demonstrated that olfactory bulb volume assessed with magnetic resonance imaging is related to the olfactory function both in normal and pathological conditions. It has been shown that olfactory bulb volume changes with the degree of olfactory dysfunction, that it decreases with the duration of the olfactory loss and that patients with qualitative disorder such as parosmia have smaller olfactory bulbs than patients without parosmia. In this review, we will discuss the actual knowledge regarding olfactory bulb function, practical ways to measure olfactory bulb volume and olfactory sulcus depth, and report systematic observations regarding these measurements related to various causes of olfactory dysfunction, e.g. infection of the upper respiratory tract, head trauma, or neurodegenerative disease. Measurement of olfactory bulb volume may provide valuable information for patients with olfactory dysfunction.

How to measure olfactory bulb volume and olfactory sulcus depth?

In combination with psychophysical testing and electrophysiological studies, magnetic resonance imaging plays a role in the clinical evaluation of patients with an olfactory dysfunction. Quantitative measurements of olfactory bulb volume and of olfactory sulcus depth, and the morphological depiction of structural abnormalities, make synergistic contributions to the accurate radiological diagnosis of smell dysfunction. Moreover, the plasticity of our olfactory system can be demonstrated by temporal changes in OB volumetric measurements. In this paper, we provide an outline of how to measure olfactory bulb volume and olfactory sulcus depth, with numerous illustrative cases of patients with congenital anosmia, post-infectious or posttraumatic olfactory loss and sinonasal-related olfactory dysfunction.

Hyperacute intraventricular hemorrhage: detection and characterization, a comparison between 5 MRI sequences

We aimed to evaluate the diagnostic accuracy of MRI for detecting early intraventricular hemorrhage (IVH) (within 6 hours after hemorrhage and to describe the MR features that allow diagnosis. For this purpose, MR data of 22 patients with hyperacute intraparenchymal hemorrhage were independently rated as negative or positive for IVH by two observers, in a blind, retrospective study taking computed tomography (CT) as providing the correct diagnosis of IVH. Sensitivity, specificity, intra- and interobserver agreement were assessed. On FSE-FLAIR, EPI-GRE-T2* and DWI images, all cases of IVH were correctly rated (sensitivity of 100%). For b0 EPI images, obtained from diffusion-weighted echo planar sequences, one case of IVH was missed by one reader (sensitivity of 88%). For T1 images, one patient was incorrectly rated negative for IVH by the two readers (sensitivity of 90%). Three forms of IVH were described, including clotted hematoma, layered hemorrhage and red blood cell deposit. When CT images were obtained within a time span of less than 3 hours after MRI, volume was assessed. Volume of hemorrhage on CT correlated best with DWI images but was underestimated on EPI-GRE T2* images.

Ischemic Cerebral Lesions after Carotid Surgery and Carotid Stenting

OBJECTIVES

To evaluate the risk of new ischemic cerebral lesions after carotid endarterectomy and carotid stenting and their clinical significance.

METHODS

Prospective and non-randomized single-center study including 121 patients with symptomatic and asymptomatic significant carotid stenosis. 60 patients were treated by surgery and 61 treated by carotid stenting. Stenting was restricted to patients at high risk for surgery. Neurological examination and Diffusion-Weighted Cerebral Magnetic Resonance (DW-MRI) were performed before and after each procedure. The presence, location and volume of new cerebral lesions were determined.

RESULTS

In the surgical group, 2 minor strokes were registered. DW-MRI showed new lesions in 7 patients (11.6%). All except one were located in the ipsilateral anterior circulation. In the stenting group, 1 minor stroke and 1 occurrence of quadranopsia were registered. DW-MRI showed new lesions in 26 patients (42.6%). 10 of these patients (38.4%) had lesions in the contralateral hemisphere and 7 patients (26.9%) in the posterior circulation. Deficits are found in patients with higher lesion volumes.

CONCLUSIONS

Cerebral ischemic lesions are significantly (p<0.0001) more frequent after carotid stenting than after endarterectomy. The majority of these lesions have no immediate clinical implication, but more specific tests are needed to evaluate their exact significance.

Unusual CT/MR features of putative ligamentum flavum ossification in a North African woman

To display the unusual spinal CT and MR findings in a 48-year-old North African woman presenting with two adjacent intracanalar mineralized epidural outgrowths exhibiting mature bone organization with "cortical" and "trabecular" areas and pseudoarthritic changes at their interface. An unusual form of ligamentum flavum ossification (LFO) was speculated, of which features are discussed under the light of the available literature.

Microsurgical results with large vestibular schwannomas with preservation of facial and cochlear nerve function as the primary aim

OBJECTIVE

To evaluate our microsurgical results in dealing with vestibular schwannomas (VS) greater than or equal to 30 mm when preservation of cranial nerve function was considered more important than total tumour removal.

METHODS

Sixteen consecutive cases were operated on by the same neurosurgeon according to a prospective protocol using intraoperative neuro-monitoring (IONM) based on electromyographic and brain stem auditory evoked potential recordings. Facial nerve function was evaluated on the House-Brackmann Scale and cochlear nerve function on the Gardner-Robertson Scale. Someone not involved in the clinical management of our patients collected all data.

RESULTS

Fifteen patients showed facial nerve (FN) function of House-Brackmann grade (HBG) I or II at one year postoperatively and one kept the HBG IV she had preoperatively. Two patients of four maintained a cochlear nerve function of Gardner-Robertson grade (GRG) II. The tumour excision rates were: total, 68.7%; near total, 6.3%; subtotal, 18.7%, and partial, 6.3%. The average follow-up was 55 months (1-106). Three patients underwent radiotherapy later with growth stabilisation and no additional morbidity.

CONCLUSION

When dealing with VS greater than or equal to 30 mm, microsurgery guided by IONM, with a rate of total or near-total tumour excision of about 75%, can retain socially acceptable facial nerve function (HBG I or II) in all cases and serviceable hearing (GRG I or II) in two cases out of four. Maintaining serviceable cranial nerve function should take precedence over total tumour excision.

Paucisymptomatic brainstem lesions revealing CNS schistosomiasis

We describe clinical and magnetic resonance (MR) features in a 69-year-old, Caucasian woman presenting with an unusual meningeal onset of cerebral schistosomiasis. Magnetic resonance work-up demonstrated supra- and infratentorial lesions with prominent brainstem involvement contrasting with the paucisymptomatic clinical presentation. Because of a recent stay in Uganda, including swimming in Lake Victoria, a diagnosis of neuroschistosomiasis was suggested. Serological tests and rectal biopsy confirmed the putative diagnosis. The patient was successfully treated with praziquantel at a dose of 50 mg/kg/day for 15 days. Brain MRI abnormalities improved dramatically within two months.

Detection of oligoclonal free kappa chains in the absence of oligoclonal IgG in the CSF of patients with suspected multiple sclerosis

BACKGROUND

Oligoclonal free kappa bands are present as frequently as oligoclonal IgG bands in the cerebrospinal fluid (CSF) from patients with definite multiple sclerosis (MS) and can even occur in the absence of oligoclonal IgG. As such, they too are markers of an ongoing intrathecal immune process.

OBJECTIVES

To determine how frequently oligoclonal free kappa bands are detectable in the CSF from patients with clinical signs and symptoms suggestive of MS in the absence of CSF restricted oligoclonal IgG.

METHODS

An immunoaffinity mediated immunoblotting technique specific for free kappa chains was used, after isoelectric focusing of paired CSF and serum samples from 33 patients with clinical signs and symptoms suggestive of MS but without CSF oligoclonal IgG. CSF data were correlated with MRI results in the context of the new diagnostic criteria from McDonald et al.

RESULTS

Eighteen CSF samples contained oligoclonal free kappa bands (54%), mainly from patients with motor dysfunction (83%) and optic neuritis (64%). All patients with a positive MRI according to Barkhof's criteria (n = 6) had free kappa bands in their CSF.

CONCLUSIONS

(1) Oligoclonal free kappa bands in the CSF are related to the dissemination of MS lesions; (2) such bands should be looked for in oligoclonal IgG negative CSF, and (3) the presence of free kappa bands in the CSF may be a substitute for oligoclonal IgG in the McDonald's criteria for diagnosis of MS.

[MRI of closed head injury]

The superiority of MR imaging to demonstrate the presence of intra- or extra-axial hemorrhage or edematous lesions, including axonal injuries, following closed head trauma has been proven over the last 15 years. CT remains the initial imaging modality in the evaluation of these patients because it is easier to obtain and allows detection of lesions requiring immediate surgical management. However, MRI should replace CT in patients with moderate to mild trauma in order to better precise the extent and degree of injuries, especially in a context of litigation. MRI could also be used following CT to further assess patients following severe trauma for prognosis purposes and better classification of traumatic injuries as well as therapeutic management.

Familial bilateral medial parietooccipital band heterotopia not related to DCX or LIS1 gene defects

A father and his daughter displayed strictly similar focal brain dysplasia at MR examination, characterized by regional medial posterior laminar sub-cortical grey matter heterotopia. To our knowledge, no family presenting such anomalies has yet been described. LIS1 and DCX gene defects were excluded. Collecting patients with such inherited dysplasia should improve our knowledge of the genetic basis of cortical malformations.

Discrepant time course of cranial and spinal subdural collections in a case of SIH treated by EBP

The MR monitoring of a patient with acute spontaneous intracranial hypotension successfully treated by epidural blood patch revealed strikingly different time course of the initially concomitant cranial and spinal subdural fluid collections. This undescribed feature suggested different pathophysiological mechanisms for the disorder in the two locations and should be kept in mind when imaging patients with the condition.

Apparent diffusion coefficient measurements within intracranial epidermoid cysts in six patients

The purpose was to determine whether a strong decrease in apparent diffusion coefficient (ADC) within epidermoid cysts (ECs) is actually responsible for their bright signal intensity on diffusion-weighted (DW) trace images. We studied six patients with surgically proven ECs in whom ADC calculation from T2-weighted DW-EPI-SE data were performed within the ECs and within the deep white matter and cerebrospinal fluid (CSF) as references. All ECs displayed highest signal intensity on the DW trace images. ADC values ranged from 1,280 to 807 x 10(-6) mm(2)/s within cysts (with a mean value of 1,070), from 849 to 698 x 10(-6) mm(2)/s within white matter (with a mean value of 764) and from 3,370 to 2,980 x 10(-6) mm(2)/s within CSF (with a mean value of 3,185). ECs exhibited slightly higher ADC values than white matter, and not the strongly decreased ones which would have been expected if diffusion-weighting were the prominent mechanism for bright signal intensity of the ECs on DW images. However, the EC ADC values are much lower than those of the CSF. Other mechanisms must therefore be involved, i.e. the T2 shine-through effect. Reduced ADC is not the only explanation of the EC bright signal intensity on the DW trace images.

Concurrent spinal cord and vertebral bone marrow radionecrosis 8 years after therapeutic irradiation

Concurrent radionecrosis within the spinal cord and the bone marrow at the same thoracic level was observed 8 years after localized therapeutic irradiation in a patient who had undergone repeated cycles of radiotherapy, glucocorticoid treatment, and chemotherapy for a non-Hodgkin's lymphoma. Mechanisms combining radiotoxic potentialization by glucocorticoids/alkylating agents and delayed radiation-induced vasculitis involving the common arterial pathways to the spinal cord and to the vertebrae were speculated to have acted in a synergistic way.

[Susac syndrome in a man]

The association of an acute encephalopathy, neurosensory hearing loss and retinal branch artery occlusions in a 35 year old man as well as the absence of systemic disease suggest the diagnosis of Susac's syndrome. This is the eighth male case described, the syndrome being more frequently reported in females.

Is there an apparent diffusion coefficient threshold in predicting tissue viability in hyperacute stroke?

BACKGROUND AND PURPOSE

Rapid and precise identification of the penumbra is important for decision-making in acute stroke. We sought to determine whether an early and moderate decrease in the apparent diffusion coefficient (ADC) may help to identify, within the diffusion/perfusion (DWI/PWI) mismatch, those areas that will eventually evolve toward infarction.

METHODS

We reviewed 48 patients not treated by thrombolytics who had a DWI/PWI within 6 hours after onset, with infarct evolution documented by follow-up magnetic resonance on days 2 to 4. We calculated absolute values for ADC and the ADC ratio (ADCr) in (1) the initial DWI hypersignal; (2) the final volume of the infarct, ie, the follow-up fluid-attenuated inversion recovery abnormalities; (3) the infarct growth (IGR) area; and (4) the oligemic area (OLI) that remained viable despite initial hemodynamic disturbance. We tested the value of the ADC to predict tissue outcome by using discriminant analysis.

RESULTS

ADC values were marginally but significantly decreased in the IGR area (ADC 782+/-82x10(-6) mm(2)/s, ADCr 0.94+/-0.08) compared with mirror values (P=0.01) and with OLI (ADC 823+/-41x10(-6) mm(2)/s, ADCr 0.99+/-0.07; P=0.001). Of all quantitative DWI and PWI parameters, the ADCr best discriminated between IGR and OLI (F(1,50)=13.6, cutoff=0.97, 64% sensitivity, 92% specificity) and between the final volume of infarct and OLI (F(1,83)=219, cutoff=0.91, 91% sensitivity, 100% specificity).

CONCLUSIONS

A simple approach based on ADC alone may allow the identification of tissue at risk of infarction in acute-stroke patients.