Medullary Lesions Research Articles

MRI-Based Neuroanatomical Predictors of Dysphagia, Dysarthria, and Aphasia in Patients with First Acute Ischemic Stroke

Background: Due to the high post-stroke frequency of dysphagia, dysarthria, and aphasia, we developed comprehensive neuroanatomical, clinical, and demographic models to predict their presence after acute ischemic stroke. Methods: The sample included 160 randomly selected first-ever stroke patients with confirmed infarction on magnetic resonance imaging from 1 tertiary stroke center. We documented acute lesions within 12 neuroanatomical regions and their associated volumes. Further, we identified concomitant chronic brain disease, including atrophy, white matter hyperintensities, and covert strokes. We developed predictive models using logistic regression with odds ratios (OR) and their 95% confidence intervals (95% CI) including demographic, clinical, and acute and chronic neuroanatomical factors. Results: Predictors of dysphagia included medullary (OR 6.2, 95% CI 1.5–25.8), insular (OR 4.8, 95% CI 2.0–11.8), and pontine (OR 3.6, 95% CI 1.2–10.1) lesions, followed by brain atrophy (OR 3.0, 95% CI 1.04–8.6), internal capsular lesions (OR 2.9, 95% CI 1.2–6.6), and increasing age (OR 1.4, 95% CI 1.1–1.8). Predictors of dysarthria included pontine (OR 7.8, 95% CI 2.7–22.9), insular (OR 4.5, 95% CI 1.8–11.4), and internal capsular (OR 3.6, 95% CI 1.6–7.9) lesions. Predictors of aphasia included left hemisphere insular (OR 34.4, 95% CI 4.2–283.4), thalamic (OR 6.2, 95% CI 1.6–24.4), and cortical middle cerebral artery (OR 4.7, 95% CI 1.5–14.2) lesions. Conclusion: Predicting outcomes following acute stroke is important for treatment decisions. Determining the risk of major post-stroke impairments requires consideration of factors beyond lesion localization. Accordingly, we demonstrated interactions between localized and global brain function for dysphagia and elucidated common lesion locations across 3 debilitating impairments.

Phrenic Nerve Stimulation – and Chorda Tympani Nerve Stimulation – May Prevent Lethal Cardiac Arrhythmias During Sleep Apnea with Heart Failure

Medical investigators in the 21 st century have increasingly focused on neurotransmitter abnormalities in the medulla oblongata as the primary etiology of Sudden Infant Death Syndrome(1) and also as the etiology of sudden unexpected deaths that occur in adults with Multiple System Atrophy(2) – serotonin is the problem in both instances.Investigators have also reported numerous cases in which the presence of a very small anatomical medullary brain lesion, like a plaque of demyelinated white matter(3), was associated with sudden unexpected death(4,5) – and in all cases the lesions were without mass effect or hemorrhage(6). Many such medullary lesions have otherwise produced only minor clinical symptoms and have in themselves been previously considered relatively harmless – in cases where they have been known to be present.Many victims have been considered healthy prior to sudden death, and the medullary brain lesions were often incidental discoveries at autopsy, with no other causes of death identified.

Sleep Related Hypoventilation Disorder in the Absence of Medullary Lesion in a Patient with Diffuse Axonal Injury

Sleep Related Hypoventilation Disorder in the Absence of Medullary Lesion in a Patient with Diffuse Axonal Injury

Autologous Hematopoietic Stem Cell Transplantation in Multiple Myeloma for Long-Term Follow-up: Single Center Results

Objective: To evaluate the efficacy and long-term outcome of the total treatment of induction therapy, ASCT and consolidation and maintenance therapy.Methods: A retrospective analysis was made on in multiple myeloma patients in our center between April 1, 2003 and February 1, 2016. The 157 patietns received autologous hematopoietic stem cell transplantation and review the autologous transplantation of long-term follow-up results. Analysis of the effect of transplantation efficacy, the impact on survival remission of different transplantation depth, transplantation in first line or not, salvage transplantation, prognosis of different staging system and other factors. Results: The baseline characteristics of the patients were shown in table 1. Overall patient ASCT before total effective rate (ORR) was 93.6%, in which the complete remission (CR) ratio was 33.1%. After ASCT, the best treatment response rate of PR was 80.3%, and the rate of CR was 58.6%. 91.69 months of median follow-up, patients with an overall survival (OS) and progression free survival (PFS) respectively 91.69 and 50.76 months; in 2005 before the median OS and PFS 39.0m and 23.0m. In 2005 after respectively and 56.41m 120.90m, P = 0.000. The median OS and PFS in the first line transplantation group and salvage transplantation group were vs 54.21m 39.0m and vs 7.09m 119.0m (P value was 0). 136 cases of patients with R-ISS stage, I, II, III of the patients with the median survival time were 120.90m (n=46), 86.43m (n=69), 35.65m (n=21), there were significant differences between groups, p=0.000. Each period of PFS were 72.11m, 51.84m, 28.09m, I and II, III, p=0.001 and p=0.03, while there was no significant difference between II and III, p=0.122. The received autologous transplantation as first-line and salvage treatment of patients with subgroup survival analysis, median OS of the R-ISS stage III patients and different 15.84m 35.65m, P = 0.031; two groups of patients the median PFS (phase I: 91.69m vs18.92m; II: vs 16.69m 53.42m; phase III: vs 5.91m 28.52m) have difference (P = 0.000). In the first-line transplantation group, transplantation is more than or equal to PR and did not get effective PR group between OS were significantly different; before transplantation achieved CR, PR but did not obtain Cr and did not get effective PR group between PFS were significantly different; after transplantation and achieved CR CR did not get the patients had a median PFS were 65.57m 48.13m, P = 0.039 and median OS no difference. Accept any kind of noval agent- based chemotherapy were significantly longer OS and PFS than traditional chemotherapy (P = 0.001, P = 0.004) .There was no obvious difference on median OS between based regimen (bortezomib group median OS: NR; thalidomide group:120.90m); PFS in thalidomide group (median PFS : NR vs 54.21m) significantly prolonged (P = 0.010). By comparing the baseline characteristics of the two groups, it was found that the PFS was significantly shorter in the bortezomib group with an extra medullary lesion. Multivariate analysis showed that only R-ISS and the depth of remission before transplantation had effect on OS (p=0.003) and PFS (p=0.036) respectively.Conclusion: The total treatment of novel agent-based chemotherapy and ASCT for transplantation-eligible multiple myeloma patients is effective, further improve the remission rate and remission depth, prolong PFS and OS, the overall median survival up to 120.9m. First line transplantation can significantly prolong the OS and PFS compared with salvage transplantation. R-ISS and pre-transplant remission depth are prognostic factors influencing survival of patients. The total treatment to thalidomide based without extramedullary perhaps makes patients get long-term survival. DisclosuresNo relevant conflicts of interest to declare.

Simplified response monitoring criteria for multiple myeloma in patients undergoing therapy with novel agents using computed tomography

IntroductionMultiple myeloma is a malignant hematological disorder of the mature B-cell lymphocytes originating in the bone marrow. While therapy monitoring is still mainly based on laboratory biomarkers, the additional use of imaging has been advocated due to inaccuracies of serological biomarkers or in a-secretory myelomas. Non-enhanced CT and MRI have similar sensitivities for lesions in yellow marrow-rich bone marrow cavities with a favourable risk and cost-effectiveness profile of CT. Nevertheless, these methods are still limited by frequently high numbers of medullary lesions and its time consumption for proper evaluation. ObjectiveTo establish simplified response criteria by correlating size and CT attenuation changes of medullary multiple myeloma lesions in the appendicular skeleton with the course of lytic bone lesions in the entire skeleton. Furthermore to evaluate these criteria with respect to established hematological myeloma-specific parameters for the prediction of treatment response to bortezomib or lenalidomide. Materials and methodsNon-enhanced reduced-dose whole-body CT examinations of 78 consecutive patients (43 male, 35 female, mean age 63.69±9.2years) with stage III multiple myeloma were retrospectively re-evaluated. On per patient basis, size and mean CT attenuation of 2–4 representative lesions in the limbs were measured at baseline and at a follow-up after a mean of 8 months. Results were compared with the course of lytical bone lesions as well with that of specific hematological biomarkers. Myeloma response was assessed according to the International Myeloma Working Group (IMWG) uniform response criteria. Testing for correlation between response of medullary lesions (Respmed) and response of all myeloma manifestations including osteolyses (Resptotal) was performed using the corrected contingency coefficient (Ccorr). ResultsThe correlation between Respmed based on length diameter and transverse diameter and Resptotal was perfect (Ccorr=1.0; p<0.0001) whereas the correlation based on density was moderate (Ccorr=0.54; p<0.0001). The evaluation of simplified response criteria with a measurement of only 2 medullary lesions yielded the best sensitivity and specificity valued for treatment-induced changes for the length diameter evaluation with 94.4%/95.7% for prediction of progressive disease and 78.6%/93.3% for prediction of therapy response. There were no significant differences between patients treated with bortezomib and lenalidomide (p>0.05). ConclusionMeasurements of size of a minimum of two medullary lesions is sufficient for response assessment and correlates very well with the course of lytic bone lesions and that of hematologic parameters.

Frequency of Cushing\u2019s syndrome due to ACTH-secreting adrenal medullary lesions: a retrospective study over 10 years from a single center

Cushing’s syndrome due to ectopic adrenocorticotropic hormone production from adrenal medullary lesions has occasionally been described. We retrospectively reviewed all 164 cases of Cushing’s syndrome and 77 cases of pheochromocytomas during 10 years. Of all cases with Cushing’s syndrome, only two cases (1.2 %) were due to ectopic adrenocorticotropic hormone production from adrenal medullary lesions (one case of pheochromocytoma and one case of adrenal medullary hyperplasia). Of all pheochromocytomas only the above-mentioned case (1.3 %) also gave rise to an ectopic adrenocorticotropic hormone syndrome. The clinical presentation of adrenocorticotropic hormone-secreting pheochromocytoma and adrenal medullary hyperplasia can be anything from mild to dramatic. These are rare conditions important to bear in mind in the workup of a patient with Cushing’s syndrome or with pheochromocytoma. The identification of ectopic adrenocorticotropic hormone secretion from adrenal medullary lesions can be life-saving.

Adrenal Pathology in the Adult: A Urological Pathologist's Perspective.

Adrenal gland diagnostics can pose significant challenges. In most academic and community practice settings, adrenal gland resections are encountered less frequently than other endocrine or genitourinary specimens, leading to less familiarity with evolving classifications and criteria. The unique dichotomy between cortical and medullary lesions reflects the developmental evolution of these functionally independent components. Adrenal cortical lesions at resection include hyperplasia, adenoma, and carcinoma, with some cases straddling the boundary between these distinct clinical classifications. The lack of immunohistochemical or molecular markers to definitively categorize these intermediate lesions enhances the diagnostic challenge. In addition, modified terminology for oncocytic and myxoid cortical lesions has been proposed. Medullary lesions are somewhat easier to categorize; however, the prediction of aggressive behavior in pheochromocytomas remains a challenge due to a lack of reliable prognostic biomarkers. Recent work by the Cancer Genome Atlas Project and other research groups has identified a limited subset of molecular and signaling pathway alterations in these 2 major neoplastic categories. Ongoing research to better define prognostic and predictive biomarkers in cortical and medullary lesions has the potential to enhance both pathologic diagnosis and patient therapy.

Body Image (BI) of acquired spinal cord injury (SCI) persons. Which patient care in an internal unit of physical and neurological rehabilitation. Experience of the patient care in an internal and neurological unit of PMR of the University Hospital of Liège

Define and develop the acquired SCI patient's BI care within the internal unit of physical and neurological rehabilitation center of the University Hospital of Liège: – explore the patients’ and professionals’ representations and needs of BI care; – estimate the concordances and the dissonances of the visions; – identify if a patient's BI care exists within the unit and what form it takes. Qualitative, retrospective, exploratory and inductive study. Twenty-three acquired SCI patients who had been hospitalized in the unit were individually interviewed. Professionals were interviewed in 8 focused-groups and 4 individuals interviews. BI emerges as a vast and personal notion. The representations of 2 populations are multidimensional and relatively corresponding. Several elements support a positive BI: diverse attitudes of professionals, a relation of quality between professionals and patients, individual care, peer support, an integration in the unit's social life, general information, or even education on the sexual repercussion of the SCI. Professionals report ‘lack of time’ as a limiting factor in patient's BI care. Work experience stands out as a support for the representations of the possible repercussions of the medullary lesion on BI. The link between ‘multidisciplinary care’ and ‘BI’ can be direct or indirect. ‘BI’ and ‘self-esteem’ seem difficult to split, just like ‘BI’ and ‘disabilities’. There is actually a BI care in the unit. Nevertheless, it is not structured, not formal and not connected to the caregiver's profession. Multidisciplinarity care and individualized care seem necessary. Several lines of reflections emerge from the interviews: well-being centered care, levers facilitating the BI discussion, a greater reliable link if a professional takes care regularly of the same person, a common philosophy of patient care, the interest to set up a rising awareness of new professionals, as well as more timesharing of the practical knowledge. In view of our results, relevant elements in the literature can be explored: the formalization of peer support, a BI systematic questioning, the support for coping strategies, the satisfaction follow-up of the hospitalized people, or even the model of Bailey and al (2015) which describes SCI patient's positive BI.

Clear detection of lower medullary lesions by three‐dimensional double inversion recovery imaging in a patient with neuromyelitis optica spectrum disorder

Clear detection of lower medullary lesions by three‐dimensional double inversion recovery imaging in a patient with neuromyelitis optica spectrum disorder

MRI Patterns of Isolated Lesions in the Medulla Oblongata.

Isolated lesions of the medulla oblongata are difficult to diagnose due to their rarity and high biopsy risk. Several individual case reports have been published, but a systematic descriptive study is lacking. Our study has three objectives that 1) provide a differential diagnosis, 2) describe magnetic resonance imaging (MRI) findings, and 3) propose a stepwise MRI-based approach to the isolated lesions of the medulla oblongata in nonstroke patients. We performed an institutional Review Board-approved retrospective analysis of 34 consecutive cases of isolated medullary lesions from nonstroke causes identified from our imaging database between January 2000 and May 2015. Eleven were excluded due to lack of pretreatment or follow-up MRI. MR studies were reviewed by two blinded neuroradiologists. The diagnosis, demographic data, and MR findings were reported using frequencies and proportions. An MRI-based diagnostic algorithm was proposed. Most lesions were neoplasms (47%), followed by vascular malformations (15%), demyelinating/inflammatory lesions (15%), others (12%), unknown (8%), and infection (3%). Five MRI patterns were identified: 1) cystic lesion, 2) exophytic noncystic lesion, 3) intrinsic lesion with T2 hypointensity, 4) enhancing intrinsic lesion, and 5) nonenhancing intrinsic lesion. All showing patterns 1 and 2 were neoplasms or cysts. All showing pattern 3 were vascular malformations. Patterns 4 and 5 comprised of multiple etiologies. Neoplasms are the most common cause of isolated medullary lesions in nonstroke patients. Other differential diagnoses include vascular malformations, demyelinating/inflammatory lesions, and infections. A stepwise MRI-based approach can help differentiate between various etiologies.

Ipsilateral hemiparesis in lateral medullary infarction: Clinical investigation of the lesion location on magnetic resonance imaging

BackgroundIn 1946, Opalski reported two cases of Wallenberg syndrome with ipsilateral hemiparesis (IH). His hypothesis seems to be based on the view that IH is caused by post-decussating pyramidal tract damage. Afterwards, other researchers proposed a different hypothesis that ipsilateral sensory symptoms of limbs (ISSL) or ipsilateral limb ataxia (ILA) caused by lateral medullary infarction (LMI) might lead to ipsilateral motor weakness. The present study is aimed to clarify whether IH in LMI patients is attributable mainly to ISSL/ILA or disruption of ipsilateral post-decussating pyramidal tract. MethodsThirty-two patients with acute LMI admitted during the last 13years were divided to IH Group (n=7) and Non-IH Group (n=25). Lesion location/distribution on MRI and neurological findings were compared between the two groups. ResultsLMI involved the lower medulla in all seven IH patients and 12 of 25 Non-IH patients. The lower medullary lesion extended to the cervico-medullary junction (CMJ) in four of seven IH patients and one of 12 Non-IH patients. Definitive extension to upper cervical cord (UCC) was confirmed in none of the patients. ISSL was found in two IH and three Non-IH patients all showing only superficial sensory impairments. ILA or hypotonia was observed in 57% of IH and 60% of Non-IH patients. ConclusionIH in LMI appears to be due mainly to post-decussating pyramidal tract damage at the lower medulla instead of ILA or ISSL participation.

CT imaging of bone and bone marrow infiltration in malignant melanoma—Challenges and limitations for clinical staging in comparison to 18FDG-PET/CT

Rationale of this study was the evaluation of the diagnostic value of computed tomography (CT) in the detection of bone marrow infiltration in comparison to PET/CT.Fifty patients (age 61±15.12years) with metastatic malignant melanoma underwent 18F-FDG-PET/CT, including contrast-enhanced CT. 2 readers evaluated the CT images in consensus for bone and bone marrow lesions focusing on lesion location, type and size. PET/CT was used as reference standard to estimate sensitivity, specificity, negative and positive predictive value. Moreover, the bone marrow density was estimated in the long bones and the sacral bone. Serum hamoglobin, thrombocyte level and S100 protein were correlated with the presence or absence of bone and bone marrow lesions.According to PET/CT as standard of reference, of 594 bone and medullary lesions 495 were considered malignant. Of these 77.8% were medullary, 20.4% lytic, 1% sclerotic and 0.8% mixed lytic/sclerotic. Contrast-enhanced CT yielded a lesion-based sensitivity of 36.8% and a specificity of 87.9% (PPV 93.8%; NPV 21.8%). Patient-based sensitivity and specificity were 78.8% and 82.4%, respectively. Of the missed lesions, most were medullary (95.8%). A disseminated bone marrow involvement (defined as >10 bone marrow lesions or diffuse infiltration of a whole body segment) was described in 11 cases, in 6 cases the disseminated involvement was underestimated or missed on CT. In cases with disseminated bone marrow involvement the bone marrow density was significantly higher in the humerus (p=0.04), but not in the femur or sacral bone (p=0.06). Multivariate analysis revealed no isolated effect of bone metastases on S100 serum and hemoglobin level, but both were significantly altered in patients with disseminated bone marrow involvement (p<0.05).In conclusion, the diagnostic value of computed tomography for the detection of bone marrow metastases in patients with melanoma, is limited. Especially in cases with disseminated bone marrow involvement about 50% of the cases were missed or underestimated.

Intractable Hiccup in Demyelinating Disease with Anti-Myelin Oligodendrocyte Glycoprotein (MOG) Antibody.

The patient was a 29-year-old man who presented with intractable hiccup at the onset of demyelinating disease. This was followed, in quick succession, by blurred vision, gait disturbance with myoclonic spasms and paresthesia in both legs, and the inability to urinate. Brain and spinal MRI revealed lesions in the parasagittal cingulate gyri, pulvinar, cerebral peduncles, superior colliculi, middle cerebellar peduncles, inferior medulla, and upper cervical cord (Picture). The patient was diagnosed with neuromyelitis optica spectrum disorder (NMOSD) based on the clinical findings (1). However, a serum analysis showed that the patient was negative for serum anti-aquaporin-4 (AQP4) antibody and positive for anti-myelin oligodendrocyte glycoprotein (MOG) antibody. We therefore considered that the correct diagnosis was acute demyelinating disease associated with anti-MOG-antibody. Two courses of steroid pulse therapy and oral prednisolone therapy alleviated the symptoms within two months. Although intractable hiccup is a characteristic manifestation of NMOSD with anti-AQP4-antibody (2), it can occur in patients with anti-MOG-antibody-associated diseases whose medullary lesions are not located in the area postrema.

Spinal Hansens with Pseudo Syringomyelitic Form

Spinal cord involvement is rare in leprosy but not unknown. We document an interesting case of a 56 year old male presented with progressive weakness of all four limbs with gross wasting of limb muscles and multiple painless trophic ulcers over the hands and legs. Examination revealed pan sensory loss in glove and stock distribution with suspended sensory loss for pain and temperature over the chest. Areflexia was noted in the upper limbs and brisk reflexes were present in the lower limbs. Generalized peripheral nerve thickening was noted. Leprosy was diagnosed and confirmed by nerve biopsy. Other causes of intra spinal lesions were excluded. This pseudo syringomyelitic from of leprosy is difficult to diagnose as it often mimics intra medullary spinal lesions.

Abnormal Neural Circuits Model in Central Post-stroke Pain

Central post-stroke pain (CPSP) was first described by Dejerine and Roussy as a consequence of stroke-related lesions in the thalamus [1]. CPSP can develops after both haemorrhagic and ischemic lesions occurring at any level of somato-sensory pathway of the brain, including medulla, thalamus, and cerebral cortex. CPSP is characterized by either spontaneous or evoked unpleasant sensory described as allodynia, hyperalgesia, and dysesthesia, which severely affect the quality of life. The prevalence of CPSP has been reported to be 8–55%, which is due to different locations of the lesion in the brain. Evidences suggest that the occurrence of CPSP is particularly high after lateral medullary infarction or lesions in the ventroposterior thalamus [2]. In addition, lesions in other brain areas in the somatosensory pathway also result in CPSP [3-5].

Complications et facteurs pronostiques des vessies neurogènes

ObjectivesTo determine the uronephrologic complications of neurogenic bladder and to identify the risk factors. Patients & MethodsThe authors carried out a retrospective study, involving 79 patients recruited at the service of Physical Medicine and Functional Readaptation of CHU IBN ROCHD of Casablanca, for a urodynamic evaluation. Patients presenting with neurogenic bladders were included. ResultsThe average age was 20.5 years with a female predominance. Urinary disorders were dominated by leakage (51.9%). The duration of evolution was longer in pediatric patients (6.5 years). Neurogenic bladders were usually associated with a medullary lesion. Neurogenic bladders represented 55.7% of cases. Repeated urinary infections (34.2%), uterero- hydronephrosis (22.8%), vesicoureteral reflux (20.2%), and chronic terminal kidney failure (6,3%) were the main complications. These complications were most frequent in children (69.56%) and patients with hypocompliance (92.85%). ConclusionThe main risk factor for complications in patients with neurologic and neurogenic bladders is hypocompliance, hence the importance of urodynamic exploration in the management of urinary disorders.

Decreased regional cerebral blood flow in the bilateral thalami and medulla oblongata determined by an easy Z-score (eZIS) analysis of 99mTc-ECD-SPECT images in a case of MM2-thalamic-type sporadic Creutzfeldt–Jakob disease

We report a case of autopsy-verified MM2-thalamic-type sporadic Creutzfeldt–Jakob disease (sCJD) in a 46-year-old patient with a 16-month history of abnormal behavior, progressive dementia, insomnia, and speech disturbances without family history. Neurological examination revealed progressive dementia, frontal signs, insomnia, speech disturbance, gait disturbance and bilaterally exaggerated tendon reflexes. Both brain MRI and cerebrospinal fluid examinations, including 14-3-3 protein, yielded normal results. An easy Z-score (eZIS) analysis for 99mTc-ethyl cysteinate dimer-single photon emission computed tomography (99mTc-ECD-SPECT) revealed decreased regional cerebral blood flow in the bilateral thalami and medulla oblongata. PRNP gene analysis revealed methionine homozygosity at codon 129 without mutation. Neuropathological examinations revealed severe neuronal loss, gliosis, and hypertrophic astrocytosis in the medial thalamus and inferior olivary nucleus. A slight depletion of Purkinje cells was observed. PrP immunostaining showed no obvious PrP deposits in the basal ganglia, thalamus, cerebellum, or brainstem; however, mild synaptic-type PrP deposits with some smaller plaque-like structures were only partially observed in the localized region of the frontal lobe with the spongiform change.Western blot analyses of protease-resistant PrP showed a type 2 pattern. In conclusion, eZIS analysis of 99mTc-ECD-SPECT images is useful for detecting both thalamic and medullary lesions. This is the first case of medullary lesions detected in a live patient with MM2-thalamic-type sCJD using SPECT.

Vestibular-evoked myogenic potentials in central vestibular disorders.

Vestibular-evoked myogenic potentials (VEMPs) are short latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. Although cervical and ocular VEMPs have mostly been applied to peripheral vestibular disorders, the characteristics and the diagnostic values of VEMPs have been expanded to assess the function of the central otolithic pathways. In the central nervous system, the cervical VEMPs (cVEMPs) are mediated by the vestibular nuclei and uncrossed medial vestibulospinal tract descending in the lower brainstem and spinal cord. In contrast, the ocular VEMPs (oVEMPs) reflect the function of the vestibular nuclei and the crossed vestibulo-ocular reflex (VOR) pathways, mostly contained in the medial longitudinal fasciculus (MLF). Therefore, lesions involving the vestibular nuclei can present abnormalities of both cVEMPs and oVEMPs. The medullary lesions involving the descending MLF or the spinal accessory nucleus impair cVEMPs. In contrast, the lesions involving the MLF, the crossed ventral tegmental tract, oculomotor nuclei and the interstitial nucleus of Cajal can impair oVEMPs. Patients with unilateral cerebellar infarctions may show abnormal VEMPs especially when they have the ocular tilt reaction. Delayed responses of VEMPs are characteristic of multiple sclerosis (MS). Reduced VEMP responses can be observed in patients with vestibular migraine. VEMPs are useful in evaluating central as well as peripheral otolithic function that are not readily defined by conventional vestibular function tests, and can aid in detecting and localizing central lesions, especially silent brainstem lesions such as tiny infarctions or MS plaques.

Bone Regeneration and Remodeling within a Unidirectional Porous Hydroxyapatite Bone Substitute at a Cortical Bone Defect Site: Histological Analysis at One and Two Years after Implantation.

Unidirectional porous hydroxyapatite (UDPHAp) is an artificial bone substitute with a unique microstructure consisting of 100–300-µm oval pores that present the material unidirectionally. UDPHAp has a compression strength of 14 MPa and a porosity of 75%, which promotes cell migration and capillary formation within the material. Despite these advantageous properties, bone remodeling and bone formation with UDPHAp remain unclear. To examine long-term remodeling and differences in bone formation based on the defect site, trapezoidal prism-shaped UDPHAp blocks were implanted into rectangular-shaped cortical bone defects in the proximal tibia of Japanese white rabbits. Histological analysis performed at 52 and 104 weeks after implantation revealed that bone and capillaries had formed within the implanted UDPHAp material. Bone formed within the UDPHAp implanted in the cortical defect of rabbit tibia and remodel up to two years. The percentage of new bone area within UDPHAp was larger in cortical lesions than that in medullary lesions. These findings suggest that UDPHAp is a promising material for the repair of non-critical-sized cortical bone defects.

Clinical and prognostic significance of bone marrow abnormalities in the appendicular skeleton detected by low-dose whole-body multidetector computed tomography in patients with multiple myeloma.

Clinical significance of medullary abnormalities in the appendicular skeleton (AS) detected by low-dose whole-body multidetector computed tomography (MDCT) in patients with multiple myeloma (MM) was investigated. A total of 172 patients with monoclonal gammopathy of undetermined significance (MGUS) (n=17), smoldering MM (n=47) and symptomatic MM (n=108) underwent low-dose MDCT. CT values (CTv) of medullary density of AS⩾0 Hounsfield unit (HU) was considered as abnormal. Percentage of medullary abnormalities and the mean CTv of AS in patients with MGUS, smoldering MM and symptomatic MM were 18, 55 and 62% and −44.5 , −20.3 and 11.2 HU, respectively (P<0.001 and P<0.001). Disease progression of MM was independently associated with high CTv on multivariate analysis. In symptomatic MM, the presence of abnormal medullary lesions was associated with increased incidence of high-risk cytogenetic abnormalities (34.4% vs 7.7% P=0.002) and extramedullary disease (10.4% vs 0% P=0.032). It was also an independent poor prognostic predictor (hazard ratio 3.546, P=0.04). This study showed that CTv of AS by MDCT is correlated with disease progression of MM, and the presence of abnormal medullary lesions is a predictor for poor survival.