Role of serostatus in pediatric neuromyelitis optica spectrum disorders: A nationwide multicentric study.

BACKGROUND: Neuromyelitis optica spectrum disorders (NMOSD) are immune-mediated inflammatory disorders of the central nervous system (CNS) mostly presenting as optic neuritis and acute myelitis. NMOSD can be associated with seropositivity for aquaporin 4 antibody (AQP4 IgG), myelin oligodendrocyte glycoprotein antibody (MOG IgG), or can be seronegative for both. In this study, we retrospectively examined our seropositive and seronegative pediatric NMOSD patients. METHOD: Data were collected from all participating centres nationwide. Patients diagnosed with NMOSD were divided into three subgroups according to serology: AQP4 IgG NMOSD, MOG IgG NMOSD, and double seronegative (DN) NMOSD. Patients with at least six months of follow-up were compared statistically. RESULTS: The study included 45 patients, 29 female and 16 male (ratio:1.8), mean age 15.16 ± 4.93 (range 5.5-27) years. Age at onset, clinical manifestations, and cerebrospinal fluid findings were similar between AQP4 IgG NMOSD (n = 17), MOG IgG NMOSD (n = 10), and DN NMOSD (n = 18) groups. A polyphasic course was more frequent in the AQP4 IgG and MOG IgG NMOSD groups than DN NMOSD (p = 0.007). The annualized relapse rate and rate of disability were similar between groups. Most common types of disability were related to optic pathway and spinal cord involvement. Rituximab in AQP4 IgG NMOSD, intravenous immunoglobulin in MOG IgG NMOSD, and azathioprine in DN NMOSD were usually preferred for maintenance treatment. CONCLUSION: In our series with a considerable number of double seronegatives, the three major serological groups of NMOSD were indistinguishable based on clinical and laboratory findings at initial presentation. Their outcome is similar in terms of disability, but seropositive patients should be more closely followed-up for relapses.

Flocculus Herniation into the Internal Acoustic Canal in Incomplete Partition Type I: A Case Report.

In this study, we present the first case with cerebellar herniation into the internal acoustic canal in incomplete partition type I anomaly. Cerebellar herniation into the internal acoustic canal is very rare with only a few cases reported in the literature. Although it is a rare clinical situation, cerebellar herniation into the internal acoustic canal may be seen in patients with incomplete partition type I. We presented magnetic resonance imaging findings of a 3-year-old girl with a history of meningitis, middle ear effusion, and bilateral congenital sensorineural hearing loss. Magnetic resonance imaging showed bilateral incomplete partition type I malformation and an additional flocculus herniation into the right internal acoustic canal. In the presented case, predisposition to cerebrospinal fluid leak in incomplete partition type I anomaly may be the reason for cerebellar herniation into internal acoustic canal. Also, possible increased intracranial pressure due to meningitis may be a contributing factor.

SMART syndrome: a case report.

INTRODUCTION: Stroke-like migraine attacks after radiation therapy (SMART) syndrome, is a late complication of brain radiotherapy (1). Symptoms are commonly subacute in onset and involve migraine type of headache, seizures, focal neurologic deficits (2). Magnetic resonance imaging (MRI) findings are usually unilateral and posterior predominant cortical-subcortical hyperintensity, swelling and prominent gyriform (cortical and leptomeningeal) gadolinium enhancement in the areas of the brain that underwent irradiation with or without diffusion restriction (1). There is no standard treatment protocol for SMART syndrome. Antiepileptics and corticosteroids are commonly used drugs. CASE REPORT: A 65 years old woman was diagnosed with breast cancer with brain metastases and treated with more than 50 Gy brain radiotherapy. The patient presented with acute right-sided weakness and numbness, episodic myoclonic jerking of the right arm and leg, and gait instability five months later. MRI and magnetic resonance angiography of the brain with gadolinium revealed left parietooccipital cortical diffusion restriction and accompanying dilatation of the left posterior cerebral artery as new findings. Computed tomography (CT) perfusion revealed increased perfusion in the affected area. The patient was diagnosed with SMART syndrome. MANAGEMENT AND OUTCOME: The patient was treated with dexamethasone (16 mg/day) and anticonvulsant therapy. Myoclonic seizures had almost completely remitted. However, her cognitive impairment persisted, then the patient was arrested because of aspiration a month later. DISCUSSION: Besides confirming SMART syndrome, diagnostic investigations are also important to exclude other etiologies. Posterior reversible encephalopathy syndrome, post-ictal changes, meningoencephalitis, and cerebrovascular diseases are radiological differential diagnoses considered (3). Proper and early diagnosis of SMART syndrome is significant in preventing unnecessary aggressive approaches and appropriate treatment to avoid lesions of sequela.

Imaging spectrum of extracorporeal membrane oxygenation related neurologic events in children.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) can be associated with severe neurological complications increasing morbidity and mortality. We aimed to evaluate imaging findings in patients with neurological complications associated with ECMO. METHODS: Children ( < 18 years) who had ECMO support and received cross-sectional imaging (cranial CT and/ or MRI) were retrospectively evaluated. Age, gender, clinical and imaging findings were documented and the relation to ECMO duration and survival rates with imaging findings and imaging time (during ECMO or after weaning) were examined. RESULTS: Twenty children who had cranial CT/MRI during (n=6) ECMO and after weaning (n=14) were included in the study. The median duration of ECMO was 12.5 days (IQR=5-25 days) with a survival rate of 65%. Fourteen patients had positive imaging findings including ischemic stroke (n=4), hemorrhagic stroke (n=4), hypoxicischemic encephalopathy (n=2), posterior reversible encephalopathy syndrome (PRES) (n=3) and cerebral vein thrombosis (n=1). The duration of ECMO and survival rates did not significantly differ between patients with positive and unremarkable imaging findings. However, the survival rate was significantly higher (p < 0.001) and the duration of ECMO was significantly lower in patients scanned after weaning compared to patients imaged during ECMO support (p=0.033). CONCLUSIONS: Our series revealed PRES in ECMO-related neurologic events in addition to commonly reported thrombotic and hemorrhagic stroke in the literature. Availability of cross-sectional imaging and awareness of radiologists to these complications during ECMO or after weaning help in prompt diagnosis and treatment.

Pediatric head and neck rhabdomyosarcoma; the role of MRI in differentiation from other common pediatric malignant head and neck tumors.

BACKGROUND: The tumor localization/extent and imaging characteristics of rhabdomyosarcomas (RMSs) especially parameningeal type, could overlap with the common tumors of the head and neck (H&N) such as lymphoma and nasopharyngeal carcinoma (NPC). Our goal was to investigate magnetic resonance imaging (MRI) features that could favor the diagnosis of RMS over lymphoma and NPC in H&N region. METHODS: Pretreatment MRI of 42 pediatric patients (mean: 9.7±5.1 years, min-max: 2-18 years) with a recent diagnosis of RMS (n=12), lymphoma (n=14) and NPC (n=16) were retrospectively studied. Tumor localization, extension and spread were evaluated. Signal and enhancement characteristics of the tumors and the presence of necrosis were noted. ADC values were measured by using both the small sample and single slice methods. For comparison of three groups, the Kruskal Wallis test and Pairwise comparisons were used. The intra-class correlation coefficient (ICC) was calculated for the assessment of inter-observer agreement. RESULTS: Nasopharynx ±parapharyngeal space involvement was detected in 58.3% of RMSs. Rhabdomyosarcoma was more heterogeneous in T2 images compared to lymphoma (p=0.014). Rhabdomyosarcoma showed significantly higher frequency of heterogeneous enhancement (p < 0.001) and necrosis (p < 0.001) among these tumors. The mean ADC values of lymphoma were significantly lower than the values of RMS (p < 0.001) and NPC (p < 0.01) for both observers. The mean ADC values were higher in RMSs than NPCs (p > 0.05). Intra-class correlation in ADC measurements was higher for the single slice method (ICC=0.997) than the small sample method (ICC=0.989). CONCLUSIONS: Rhabdomyosarcoma tends to have higher ADC values than lymphoma and has a higher frequency of heterogeneous enhancement and necrotic parts than both lymphoma and nasopharyngeal carcinoma. These features could help radiologists to differentiate RMS from the above-mentioned mimickers.

Comparison of early- and late-phase CT angiography findings in brain death.

BACKGROUND: Late-phase images on computed tomography angiography (CTA), traditionally used for assessing cerebral circulatory arrest in brain death, suffer from suboptimal diagnostic yield due to stasis filling. Herein, we assessed contrast filling in individual intracranial arteries and veins in the early and late phases of CTA in patients with clinically confirmed brain death. METHODS: Contrast opacification within 28 arterial/venous segments was evaluated in both phases of CTA in 79 patients. This information was combined with reports in the literature to calculate prevalence of contrast filling in different intracranial vessels. Additionally, diagnostic sensitivity of 4-point, 7-point, and 10-point scores defined for brain death were compared among ratings based on early, late, and both phases (arteries rated on early, veins rated on late phase) of imaging. RESULTS: The median (IQR) number of vessel segments with contrast opacification was 0 (0-2) in early phase and 6 (0-10) in late phase. All segments showed increased prevalence of opacification when evaluated in late phase (p < 0.05). The M4 segments of MCA, internal cerebral veins, and vein of Galen had the lowest percentage of opacification in both phases. The sensitivity of 4-, 7-, and 10-point scoring algorithms increased from 59-91% to 94-99% when ratings were performed using early-phase images rather than based solely on late-phase images. CONCLUSIONS: The incorporation of early-phase images might be considered as a strategy to improve the sensitivity of CTA as an ancillary test in confirming brain death, especially in patients without missing or questionable elements in clinical examination.

Synthetic MRI in children with tuberous sclerosis complex.

OBJECTIVE: The generation of numerous sequences and quantitative data in a short scanning time is the most potential advantage of Synthetic MRI (SyMRI). We aimed to test detection of the tubers and to determine underlying tissue characteristics, and morphometric alterations in the brain of pediatric tuberous sclerosis complex (TSC) patients, using SyMRI. METHODS: Conventional brain MRI (cMRI) and SyMRI were prospectively obtained from 10 TSC patients and 18 healthy control subjects (HCs). Two neuroradiologists independently evaluated tubers on both scans. Additionally, automatically segmented volume calculation and myelin quantification, including the subcortical part of the tubers and normal-appearing brain parenchyma (NABP) of patients, were carried out using SyMRI. RESULTS: The cMRI and SyMRI comparison showed a very good correlation on the detection of the tubers (k = 0.82-0.94). Automatic segmentation of Non-gray matter/white matter/cerebrospinal fluid (Non), %Non/brain parenchymal volume, and %Non/intracranial volume was significantly higher; however, %Myelin/intracranial volume and %Myelin/brain parenchymal volume were significantly lower in the TSC patients (p < 0.05). The proton density values were significantly increased, and myelin fraction volume and myelin-correlated compound values were significantly decreased in the NABP in TSC patients on myelin maps (p < 0.05). The white-matter volume, myelin and white-matter fractional volume, longitudinal relaxation rate, transverse relaxation rate, and myelin-correlated compound values were significantly decreased in the subcortical part of tubers on quantification maps (p < 0.001) in TSC patients. CONCLUSION: SyMRI enables the detection of cortical tubers and is a developing tool in the quantification of morphometric and tissue alterations in pediatric TSC patients with a rational scanning time.

Newer disease modifying treatments in pediatric onset multiple sclerosis: Experience from a single center.

BACKGROUND: Disease modifying treatments (DMTs) for multiple sclerosis include injectable drugs (iDMTs) like interferons (IFNs) or glatiramer acetate (GA), and newer agents (nDMTs) in oral and intravenous forms. nDMTs are usually applied in escalation and less frequently as initial treatment in pediatric-onset (POMS). OBJECTIVE: We intended to evaluate the effect of nDMTs in comparison with iDMTs by retrospective examination of our patients with POMS. METHOD: Clinical records of POMS cases who received nDMTs either as escalation or initial treatment and who had at least 12 months' follow-up in our clinic were examined in two groups: patients who were started on iDMTs and later switched to nDMTs (Group A), and those who received nDMTs from the beginning (Group B). Presenting symptoms, annualized relapsing rate (ARR), recent Expanded Disability Status Scale (EDSS), lesion load and presence of contrast enhancing (CE) lesions on magnetic resonance imaging (MRI) were compared. RESULTS: Total 43 patients were included: 33 in Group A and 10 in Group B. Age at onset, female/male ratio, duration since disease onset and duration under nDMT were similar in both groups. Initial involvement was predominantly brainstem and cerebellar in Group A and sensorial, brainstem/cerebellar, and optic nerve in Group B. The most frequently used nDMT was fingolimod in Group A (n = 17, 51.5%) and teriflunomide (n = 6, 60%) in Group B. Median ARR before any treatment was 2 in Group A and 1.5 in Group B (p > 0.05); it decreased to median 1 under iDMTs in Group A and to 0 under nDMTs. Mean follow-up was 6.7 ± 5 years (1-19, median 6 years) in Group A and 3.9 ± 3.7 years (range 1-12, median 2 years) in Group B. At the latest follow-up median EDSS scores were 1 in Group A and 0 in Group B. ARR had increased and lesion load on MRI went up progressively in both groups during follow-up. However, the rate of patients with CE lesions diminished in Group B. CONCLUSION: This single-center study of POMS shows the ARR decreases under any treatment, more markedly under nDMTs, and nDMTs reduce the rate of patients with CE lesions on MRI without a clear effect on lesion load. The ARR tends to increase after the first 2 years of both iDMT and nDMT, suggesting a re-evaluation at that time. The ARR decreases shorty after treatment is changed from an iDMT to a nDMT.

X-linked deafness/incomplete partition type 3: Radiological evaluation of temporal bone and intracranial findings.

PURPOSE: X-linked deafness (XLD) is a rare disease, characterized by typical cochlear incomplete partition type 3 anomaly (IP-III). Accompanying hypothalamic anomalies were also recently described. The purpose of this study was to document the temporal bone and intracranial imaging findings in a series of patients with XLD with a review of the literature, to better understand this anomaly. METHODS: The CT and MRI studied of 13 XLD patients were retrospectively evaluated. All structures of the otic capsule (OC) were subjectively and retrospectively assessed. The OC thickness and the size of the cochlea were measured and compared to the age-matched control group. Intracranial structures were also evaluated with specific attention to the hypothalamic region. RESULTS: All cases had bilateral IP-III anomaly, bulbous internal auditory canals (IACs), absent bony modiolus with preserved interscalar septa, intact cochleovestibular, and facial nerves. OC thickness was decreased in all cases compared to the control group (p<0.001). In XLD patients, the cochlea had decreased transverse dimension and increased height compared to the control group (p< 0.001). Five patients (38.4%) had bilateral cystic structures adjacent to the vestibule and/or semicircular canals (SCCs). Hypothalamus was thickened or had a lobular appearance in all cases (subtle in one). Additionally, hamartoma-like appearance of the hypothalamus was present in half. CONCLUSION: XLD is a rare inner ear anomaly that is frequently associated with hypothalamic malformations. The OC thickness of IP-III patients appears to be decreased with accompanying decreased transverse dimension of the cochlea which could have implications in electrode selection during cochlear implantation. Cystic /diverticular lesions surrounding the vestibule and semicircular canals are also frequently seen but a rarely reported finding.

CT dose management for neurologic events in patients with cardiac devices: Radiation exposure variation in patients with cardiac devices.

PURPOSE: To compare the inter-center cranial computed tomography (CT) acquisition rates, CT findings, CT related radiation dose, and variability of CT acquisition parameters for neurologic events among patients with implantable cardioverter-defibrillator (ICD) or left ventricular assist device (LVAD). METHODS: A total of 224 patients [ICD group (n = 155) and LVAD group (n = 69)] who had at least one cranial CT scan were enrolled from three medical centers. The variability and effect of the number, indication, and findings of cranial CT scans as well as CT acquisition parameters including tube potential, tube current, tube rotation time (TI), slice collimation (cSL), and spiral or sequential scanning techniques on CT dose index volume (CTDIvol), total dose length product (DLP) were analyzed. RESULTS: The mean DLP value of Center A and mean CTDIvol values of Center A and C were significantly lower than Center B (p < 0.001). The mean CTDIvol and DLP values in the ICD group were substantially lower than the LVAD group (p<0.001). The most potent parameters causing the changes in CTDIvol and DLP were kV, mAs values, and CT scanning technique as sequential or spiral according to multivariate linear regression analysis. CONCLUSION: Cranial CT acquisition parameters and radiation doses vary significantly between centers, which necessitates optimization of cranial CT protocols to overcome the cumulative radiation dose burden in patients with neurologic events.

Reduced myelin in patients with isolated hippocampal sclerosis as assessed by SyMRI.

PURPOSE: Synthetic MRI (SyMRI) enables to quantify brain tissue and morphometry. We aimed to investigate the WM and myelin alterations in patients with unilateral hippocampal sclerosis (HS) with SyMRI. METHODS: Adult patients with isolated unilateral HS and age-matched control subjects (CSs) were included in this study. The SyMRI sequence QRAPMASTER in the coronal plane perpendicular to the hippocampi was obtained from the whole brain. Automatic segmentation of the whole brain was processed by SyMRI Diagnostic software (Version 11.2). Two neuroradiologists also performed quantitative analyses independently from symmetrical 14 ROIs placed in temporal and extratemporal WM, hippocampi, and amygdalae in both hemispheres. RESULTS: Sixteen patients (F/M = 6/10, mean age = 32.5 ± 11.3 years; right/left HS: 8/8) and 10 CSs (F/M = 5/5, mean age = 30.7 ± 7 years) were included. Left HS patients had significantly lower myelin and WM volumes than CSs (p < .05). Myelin was reduced significantly in the ipsilateral temporal lobe of patients than CSs, greater in left HS (p < .05). Histopathological examination including luxol fast blue stain also revealed myelin pallor in all of 6 patients who were operated. Ipsilateral temporal pole and sub-insular WM had significantly reduced myelin than the corresponding contralateral regions in patients (p < .05). No significant difference was found in WM values. GM values were significantly lower in hippocampi in patients than CSs (p < .05). CONCLUSION: SyMRI revealed myelin reduction in the ipsilateral temporal lobe and sub-insular WM of patients with HS. Whether this finding correlates with electrophysiological features and SyMRI could serve as lateralization of temporal lobe epilepsy need to be investigated.

3 Tesla MR imaging of the large endolymphatic duct and sac anomaly with audiological correlation.

PURPOSE: Large endolymphatic duct and sac (LEDS) is one of the most common imaging abnormalities in congenital sensorineural hearing loss and is frequently seen with coexistent cochlear anomalies, especially incomplete partition type II. However, MRI findings of accompanying cochlear and especially modiolar dysplasias may be subtle. The purpose of this study is to evaluate the imaging findings of LEDS with high-resolution imaging at 3 T and correlate with the audiological data. METHODS: 3 T temporal bone MRIs of 54 ears in 30 LEDS patients were retrospectively evaluated. The cochlear dysmorphism and modiolar deficiency were assessed qualitatively and quantitatively. The severity of LEDS anomaly, the signal changes within the LEDS and cochlea were also noted. The imaging findings were correlated to the audiological data. RESULTS: The cochlea was abnormal in 77.8% of the ears with an isolated modiolar deficiency in 11.1%. Cochlea and modiolus were completely normal in 11.1% of the ears. In 63% of the ears X-distance was increased. T2 hypointensity within LEDS and cochlea were detected in 42.6%, and 7.4% of the ears, respectively. The median diameters of LEDS were higher in ears with severe to profound HL than ears with normal to moderate HL (p < 0.05). The X-distance, presence of T2 hypointensity within LEDS, and diameters of modiolus did not show statistical correlation with the audiographic data. CONCLUSION: High-resolution 3 T imaging of patients with LEDS anomaly revealed a spectrum of cochlear anomalies, but up to 11.1% of the ears had no underlying anomaly despite severe (endolymphatic duct/sac) dilatation and/or profound HL.

Volume and T2 relaxation time measurements of quadriceps femoris and hamstring muscles are reliable and reproducible

Background/aim: Volume and T2 relaxation time measurements of the skeletal muscle provide quantitative information. We aimed to evaluate the interobserver reliability and the intraobserver reproducibility of measurements of volumes and T2 relaxation times of the quadriceps femoris and the hamstring muscles. Materials and methods: A cross-sectional reliability study was conducted on ten recreational athletes. The images of the quadriceps and the hamstring muscles of both limbs were obtained using a 3.0 Tesla magnetic resonance imaging (MRI) scanner. Two sports medicine specialists measured muscle volumes from a total of 2560 images and T2 relaxation times from a total of 40 images, and repeated this once more. The intraobserver and interobserver compliance were assessed by the intraclass correlation coefficient (ICC) and Cronbach's alpha (α). Results: Volume and T2 relaxation time of quadriceps femoris and hamstring muscle measurements with MRI had good to excellent reliability (Muscle volume; intraobserver ICCs: between 0.97 and 0.99, α: between 0.98 and 0.99 and interobserver ICCs: between 0.96 and 0.99, α: 0.99. T2 relaxation time; intraobserver ICCs: between 0.74 and 0.96, α: between 0.85 and 0.98 and interobserver ICCs: between 0.75 and 0.90, α: between 0.85 and 0.95). Conclusion: Volume and T2 relaxation time measurements of the quadriceps femoris and the hamstring muscles are reliable and reproducible.

Diffusion-weighted imaging for the differentiation of Ewing sarcoma from osteosarcoma.

OBJECTIVE: The purpose of this study is to assess the ability of apparent diffusion coefficient (ADC) values in differentiating Ewing sarcoma and osteosarcoma. MATERIALS AND METHODS: This retrospective cross-sectional observational study included a total of 35 patients with a recent diagnosis of Ewing sarcoma (n = 13) and osteosarcoma (n = 22) who underwent conventional MRI and diffusion-weighted imaging (DWI). Three ADC measurements from the areas of the lowest diffusivity in ADC maps (ADCmin), and other areas with low diffusivity (ADCother), were made independently by two observers on pre-treatment MRI, and the means of these measurements were compared using independent samples t-test. Intraclass correlation coefficient was calculated for inter-observer agreement. RESULTS: There was a significant difference between the ADCmin (P < 0.001) and ADCother (P < 0.001) in Ewing sarcoma and osteosarcoma for both observers. For Ewing sarcoma and osteosarcoma, mean ADCmin was 0.566 ± 0.07 and 1.193 ± 0.33 × 10-3 mm2/s; 0.551 ± 0.08 and 1.182 ± 0.33 × 10-3 mm2/s; and mean ADCother was 0.813 ± 0.11 and 1.510 ± 0.35 × 10-3 mm2/s; 0811 ± 0.12 and 1.501 ± 0.33 × 10-3 mm2/s for observers 1 and 2, respectively. Inter-observer correlation coefficient for mean ADCmin was 0.994 and for mean ADCother was 0.995. CONCLUSION: Diffusion-weighted imaging and ADC values could be used in the differentiation of Ewing sarcoma and osteosarcoma in borderline cases.

Temporal encephaloceles can be missed in patients with refractory temporal lobe epilepsy.

Temporal encephaloceles (TEs) are one of the cause of refractory temporal lobe epilepsy (TLE). We reviewed the neuroimaging and video-electroencephalography (EEG) records of epilepsy patients who underwent temporal lobectomy in our center to investigate frequency of TEs. We retrospectively reevaluated 294 patients who underwent epilepsy surgery in our tertiary epilepsy centre between January 2010 and March 2019 and included 159 patients (78 females, 49 %; 81 males) who had temporal lobectomy. Preoperatively, TEs were reported in 3 of 159 patients (1 female, 2 males). After reevaluation 4 more patients with TEs (1 female, 3 males) were added. The ratio of TE in patients who underwent temporal lobectomy increased from 1.8 % (n=3) to 4,4 % (n=7). The median ages were 18 (range 16-22) versus 10 years (range 5-17) at habitual seizure onset and the median of epilepsy duration was 5 (range 3-15) versus 175 (range 11-25) years between patients with and without TE. Habitual seizure onset age was significantly higher (p =, 007) in the patients with encephalocele and epilepsy duration was shorter (p =, 003) than patients without encephalocele. The ictal EEG records of all patients TE rhythmic delta activity which is suggested neocortical temporal lobe onset seizures. 4 of 7 patients' PET imaging showed temporal lobe hypometabolism compatible with ipsilateral to the TEs. The three patients underwent anterior temporal lobectomy without amygdalohippocampectomy and others had anterior temporal lobectomy with amygdalohippocampectomy. We suggested that there might be some clues for temporal encephalocele, an easily overlooked cause in patients with nonlesional temporal lobe epilepsy.TLE patients with TE had relatively late onset of epilepsy and rhythmic delta activity on ictal EEG. Also, temporal hypometabolism on PET may be a useful key to suspicion of TE.

The evolution of bone marrow signal changes at the skull base in nasopharyngeal carcinoma patients treated with radiation therapy.

BACKGROUND: Clival infiltration is frequently seen in nasopharyngeal carcinoma (NPC) and the resultant bone marrow signal changes (BMSC) can persist even after complete tumor response to the radiation therapy (RT). The differentiation of those residual BMSC from recurrent/persistent disease may be challenging. We performed serial analysis of the clival BMSC after RT, to define an expected temporal evolution of those signal changes during the follow-up. MATERIALS AND METHODS: Serial MRI studies of 50 NPC patients (with or without initial clival infiltration) who had undergone RT were retrospectively examined. Abnormal clival BMSC and contrast enhancement (CE) were evaluated on each follow-up scan. Duration of BMSC/CE was correlated with the degree of baseline clival involvement (BCID), RT dose, and primary mass volume (PMV). RESULTS: Clival BMSC persisted without any evidence of recurrence, for a mean of 66.5 (max. 137) months (with accompanying CE for up to 125 months) in 26 patients with clival infiltration at diagnosis. Duration of BMSC and CE showed statistical correlations with PMW (p < 0.05), but not with RT dose or BCID. The rate of recurrence in clivus was 14%. New clival lesions that occurred within the first 12 months after RT (in six patients) did not develop recurrence suggesting radiation osteitis (12%). CONCLUSION: After RT, residual clival medullary signal change/enhancement is seen in most NPC patients and can persist even years without recurrence.

Skull base osteomyelitis: Comprehensive analysis and a new clinicoradiological classification system.

OBJECTIVE: Skull baseosteomyelitis (SBO) is a rare phenomenon that typically occurs in diabetic or immunocompromised patients, causing significant morbidity and mortality. This study aimed to analyze a single institution's treatment results in SBO patients and propose anew integrated clinicoradiological classification system. METHODS: The medical records of 32 SBO patients that were treated at a tertiary care center between 2006 and 2017 were retrospectively reviewed. A scoring system based on anatomical involvement according to MRI was created. Subsequently, the scoring system was integrated with cranial nerve dysfunction status and a clinical grading system (CGS) was proposed. RESULTS: Among the 32 patients, 78.1% were diabetic and 63% had cranial nerve dysfunction at presentation. Bone erosion based on CT was greater in the patients without regression (P = 0.046). The regression rate decreased from clinical grade (CG)1 to CG3 (P = 0.029). Duration of hospitalization increased as CG increased (P = 0.047). Surgery had no effect on regression status at the time of discharge (P = 0.41). The 1-year, 2-year, and 5-year overall survival rates were 82.2%, 70.8%, and 45.8%, respectively. CG was significantly correlated with overall survival but not with disease-specific survival (log-rank; P = 0.017, P = 0.362, respectively). CONCLUSION: SBO continues to pose a challenge to clinicians, and causes significant morbidity and mortality. The proposed new classification system can be an option for grouping SBO patients according to clinical and radiological findings, helping clinicians estimate prognosis.

Single shot echo planar imaging (ssEPI) vs single shot turbo spin echo (ssTSE) DWI of the orbit in patients with ocular melanoma.

OBJECTIVES: Diffusion weighted imaging (DWI) has become important for orbital imaging. However, the echoplanar imaging (EPI) DWI has inherent obstacles due to susceptibility to magnetic field inhomogeneities. We conducted a comparative study assessing the image quality of orbits in a patient cohort with uveal melanoma (UM). We hypothesized that single shot turbo spin echo (ssTSE) DWI would have better image quality in terms of less distortion and artifacts and yield better tissue evaluation compared to ssEPI-DWI. METHODS: ssEPI-DWI and ssTSE-DWI of orbits were obtained from 50 patients with uveal melanoma who were prospectively enrolled in the study. Distortion ratio (DR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diffusion signal properties, and apparent diffusion coefficient (ADC) values were collected and compared between ssEPI-DWI and ssTSE-DWI. Two reviewers evaluated and compared the geometric distortion, susceptibility and ghosting artifacts, resolution, demarcation of ocular mass, and overall quality. RESULTS: A higher DR was found in ssEPI-DWI compared to ssTSE-DWI (p < 0.001). SNR and CNR were lower for the temporal lobe cortex (p ≤ 0.004), but higher for melanoma in ssEPI-DWI than ssTSE-DWI (p ≤ 0.037). Geometric distortion and artifacts were more common in ssEPI-DWI (p < 0.001). Resolution (p ≤ 0.013) and overall quality (p < 0.001) were better in ssTSE-DWI. Ocular masses were demarcated better on ssEPI-DWI (p ≤ 0.002). Significant negative correlations between T1 and T2 signal intensities (r = -0.369, p ≤ 0.008) and positive correlations between T2 and both DWI signal intensities (r = 0.686 and p < 0.001 for ssEPI-DWI, r = 0.747 and p < 0.001 for ssTSE-DWI) were revealed. CONCLUSION: With less geometric distortion and susceptibility artifacts, better resolution, and overall quality, ssTSE-DWI can serve as an alternative to ssEPI-DWI for orbital DWI. ADVANCES IN KNOWLEDGE: ssTSE-DWI can be a better alternative of diffusion imaging of orbits with less susceptibility artifact and geometric distortion compared to ssEPI-DWI.