Association Between Dispatch of Mobile Stroke Units and Functional Outcomes Among Patients With Acute Ischemic Stroke in Berlin.

Importance: Effects of thrombolysis in acute ischemic stroke are time-dependent. Ambulances that can administer thrombolysis (mobile stroke units [MSUs]) before arriving at the hospital have been shown to reduce time to treatment. Objective: To determine whether dispatch of MSUs is associated with better clinical outcomes for patients with acute ischemic stroke. Design, Setting, and Participants: This prospective, nonrandomized, controlled intervention study was conducted in Berlin, Germany, from February 1, 2017, to October 30, 2019. If an emergency call prompted suspicion of stroke, both a conventional ambulance and an MSU, when available, were dispatched. Functional outcomes of patients with final diagnosis of acute cerebral ischemia who were eligible for thrombolysis or thrombectomy were compared based on the initial dispatch (both MSU and conventional ambulance or conventional ambulance only). Exposure: Simultaneous dispatch of an MSU (computed tomographic scanning with or without angiography, point-of-care laboratory testing, and thrombolysis capabilities on board) and a conventional ambulance (n = 749) vs conventional ambulance alone (n = 794). Main Outcomes and Measures: The primary outcome was the distribution of modified Rankin Scale (mRS) scores (a disability score ranging from 0, no neurological deficits, to 6, death) at 3 months. The coprimary outcome was a 3-tier disability scale at 3 months (none to moderate disability; severe disability; death) with tier assignment based on mRS scores if available or place of residence if mRS scores were not available. Common odds ratios (ORs) were used to quantify the association between exposure and outcome; values less than 1.00 indicated a favorable shift in the mRS distribution and lower odds of higher levels of disability. Results: Of the 1543 patients (mean age, 74 years; 723 women [47%]) included in the adjusted primary analysis, 1337 (87%) had available mRS scores (primary outcome) and 1506 patients (98%) had available the 3-tier disability scale assessment (coprimary outcome). Patients with an MSU dispatched had lower median mRS scores at month 3 (1; interquartile range [IQR], 0-3) than did patients without an MSU dispatched (2; IQR, 0-3; common OR for worse mRS, 0.71; 95% CI, 0.58-0.86; P < .001). Similarly, patients with an MSU dispatched had lower 3-month coprimary disability scores: 586 patients (80.3%) had none to moderate disability; 92 (12.6%) had severe disability; and 52 (7.1%) had died vs patients without an MSU dispatched: 605 (78.0%) had none to moderate disability; 103 (13.3%) had severe disability; and 68 (8.8%) had died (common OR for worse functional outcome, 0.73, 95% CI, 0.54-0.99; P = .04). Conclusions and Relevance: In this prospective, nonrandomized, controlled intervention study of patients with acute ischemic stroke in Berlin, Germany, the dispatch of mobile stroke units, compared with conventional ambulances alone, was significantly associated with lower global disability at 3 months. Clinical trials in other regions are warranted.

Lumbar puncture rapidly improves olfaction in patients with idiopathic intracranial hypertension: A cohort study.

BACKGROUND: A lumbar puncture constitutes an important diagnostic procedure in the evaluation of idiopathic intracranial hypertension. Chronic overflow of cerebrospinal fluid into the sheaths of the olfactory nerves appears to be related to olfactory impairment in these patients. Here, we asked whether cerebrospinal fluid drainage in idiopathic intracranial hypertension patients improves olfactory function. METHODS: Fourteen idiopathic intracranial hypertension patients and 14 neurologic control patients were investigated before and after lumbar puncture using the extended Sniffin' Sticks procedure. We assessed odor threshold, discrimination, and identification. In idiopathic intracranial hypertension patients, cerebrospinal fluid was drained until cerebrospinal fluid pressure had normalized. In addition, a third group of 14 healthy controls participated in the two smell tests at similar intervals. RESULTS: Relative to healthy controls, threshold, discrimination, and identification composite scores before lumbar puncture were significantly lower in idiopathic intracranial hypertension patients and also in neurologic controls. Following lumbar puncture, threshold, discrimination, and identification scores for neurologic controls remained unchanged whereas idiopathic intracranial hypertension patients showed robust improvement on the composite score as well as on all three subscores (all changes: p < 0.003), quickly regaining olfactory function in the normal range. Cerebrospinal fluid opening pressure was significantly correlated with improvement in threshold, discrimination, and identification score upon cerebrospinal fluid drainage (r = 0.609, p = 0.021). CONCLUSION: Olfactory impairment is an important, yet underappreciated, clinical feature of idiopathic intracranial hypertension. Lowering of increased intracranial pressure improves hyposmia. Our findings shed new light on the pathophysiology of cerebrospinal fluid circulation in idiopathic intracranial hypertension.

T2 mapping of molecular subtypes of WHO grade II/III gliomas.

BACKGROUND: According to the new WHO classification from 2016, molecular profiles have shown to provide reliable information about prognosis and treatment response. The purpose of our study is to evaluate the diagnostic potential of non-invasive quantitative T2 mapping in the detection of IDH1/2 mutation status in grade II-III gliomas. METHODS: Retrospective evaluation of MR examinations in 30 patients with histopathological proven WHO-grade II (n = 9) and III (n = 21) astrocytomas (18 IDH-mutated, 12 IDH-wildtype). Consensus annotation by two observers by use of ROI's in quantitative T2-mapping sequences were performed in all patients. T2 relaxation times were measured pixelwise. RESULTS: A significant difference (p = 0,0037) between the central region of IDH-mutated tumors (356,83 ± 114,97 ms) and the IDH-wildtype (199,92 ± 53,13 ms) was found. Furthermore, relaxation times between the central region (322,62 ± 127,41 ms) and the peripheral region (211,1 ± 74,16 ms) of WHO grade II and III astrocytomas differed significantly (p = 0,0021). The central regions relaxation time of WHO-grade II (227,44 ± 80,09 ms) and III gliomas (322,62 ± 127,41 ms) did not differ significantly (p = 0,2276). The difference between the smallest and the largest T2 value (so called "range") is significantly larger (p = 0,0017) in IDH-mutated tumors (230,89 ± 121,11 ms) than in the IDH-wildtype (96,33 ± 101,46 ms). Interobserver variability showed no significant differences. CONCLUSIONS: Quantitative evaluation of T2-mapping relaxation times shows significant differences regarding the IDH-status in WHO grade II and III gliomas adding important information regarding the new 2016 World Health Organization (WHO) Classification of tumors of the central nervous system. This to our knowledge is the first study regarding T2 mapping and the IDH1/2 status shows that the mutational status seems to be more important for the appearance on T2 images than the WHO grade.

The effect of CSF drain on the optic nerve in idiopathic intracranial hypertension.

BACKGROUND: Elevation of intracranial pressure in idiopathic intracranial hypertension induces an edema of the prelaminar section of the optic nerve (papilledema). Beside the commonly observed optic nerve sheath distention, information on a potential pathology of the retrolaminar section of the optic nerve and the short-term effect of normalization of intracranial pressure on these abnormalities remains scarce. METHODS: In this exploratory study 8 patients diagnosed with idiopathic intracranial hypertension underwent a MRI scan (T2 mapping) as well as a diffusion tensor imaging analysis (fractional anisotropy and mean diffusivity). In addition, the clinical presentation of headache and its accompanying symptoms were assessed. Intracranial pressure was then normalized by lumbar puncture and the initial parameters (MRI and clinical features) were re-assessed within 26 h. RESULTS: After normalization of CSF pressure, the morphometric MRI scans of the optic nerve and optic nerve sheath remained unchanged. In the diffusion tensor imaging, the fractional anisotropy value was reduced suggesting a tissue decompression of the optic nerve after lumbar puncture. In line with these finding, headache and most of the accompanying symptoms also improved or remitted within that short time frame. CONCLUSION: The findings support the hypothesis that the elevation of intracranial pressure induces a microstructural compression of the optic nerve impairing axoplasmic flow and thereby causing the prelaminar papilledema. The microstructural compression of the optic nerve as well as the clinical symptoms improve within hours of normalization of intracranial pressure.

Does IIH Alter Brain Microstructures? - A DTI-Based Approach.

INTRODUCTION: To investigate the correlation of microstructural parameters with CSF pressure and macroscopic changes assessed by diffusion tensor imaging (DTI) in patients with idiopathic intracranial hypertension (IIH). METHODS: Twenty-three patients with IIH as well as age-, sex-, and body mass index (BMI)-matched controls underwent high resolution MR imaging of the optic nerve sheaths (ONS), pituitary gland, and ventricles. For DTI data a voxelwise permutation analysis was performed for the whole brain and ROI analysis was performed for the optic nerve and optic radiation. DTI measurements were correlated to morphometric measurements, CSF opening pressure, and headache intensity. The reliability of diagnostic performance of DTI parameters was assessed using ROC analysis. RESULTS: Analysis of DTI metrics revealed a significant reduction in the fractional anisotropy (FA) of the optic nerve in patients with IIH. In contrast, systematic regional variations between IIH patients and controls were neither observed in the whole brain analysis nor in the optic radiation. FA values of the optic nerve show significant correlations with the optic nerve sheath diameter (P = .003, r = -.589). The correlation of the alterations of the FA values of the optic radiation and the whole brain do not show a significant association to morphometric alterations in the ONS diameter and hypophysis height as well as to CSF opening pressure and headache intensity. CONCLUSIONS: The results indicate that IIH is associated with microstructural changes in the optic nerve. These alterations may be the direct consequence of chronically elevated intracranial pressure.

Reducing radiation dose in the diagnosis of pulmonary embolism using adaptive statistical iterative reconstruction and lower tube potential in computed tomography.

OBJECTIVES: To assess the impact of ASIR (adaptive statistical iterative reconstruction) and lower tube potential on dose reduction and image quality in chest computed tomography angiographies (CTAs) of patients with pulmonary embolism. MATERIALS AND METHODS: CT data from 44 patients with pulmonary embolism were acquired using different protocols-Group A: 120 kV, filtered back projection, n = 12; Group B: 120 kV, 40 % ASIR, n = 12; Group C: 100 kV, 40 % ASIR, n = 12 and Group D: 80 kV, 40 % ASIR, n = 8. Normalised effective dose was calculated; image quality was assessed quantitatively and qualitatively. RESULTS: Normalised effective dose in Group B was 33.8 % lower than in Group A (p = 0.014) and 54.4 % lower in Group C than in Group A (p < 0.001). Group A, B and C did not show significant differences in qualitative or quantitative analysis of image quality. Group D showed significantly higher noise levels in qualitative and quantitative analysis, significantly more artefacts and decreased overall diagnosability. Best results, considering dose reduction and image quality, were achieved in Group C. CONCLUSIONS: The combination of ASIR and lower tube potential is an option to reduce radiation without significant worsening of image quality in the diagnosis of pulmonary embolism. KEY POINTS: • Iterative algorithms and lowering of tube potential reduce radiation without compromising interpretability • 40 % ASIR and 100 kV tube potential led to a 54.4 % dose reduction • 40 % ASIR and 80 kV tube potential led to significantly worse image quality.

Morphometric and volumetric MRI changes in idiopathic intracranial hypertension.

OBJECTIVE: We aimed at validating established imaging features of idiopathic intracranial hypertension (IIH) by using state-of-the-art MR imaging together with advanced post-processing techniques and correlated imaging findings to clinical scores. METHODS: Twenty-five IIH patients as well as age-, sex- and body mass index (BMI)-matched controls underwent high-resolution T1w and T2w MR imaging in a 1.5 T scanner, followed by assessment of optic nerve sheaths, pituitary gland, ventricles and Meckel's cave. Imaging findings were correlated with cerebrospinal fluid (CSF) opening pressures and clinical symptom scores of visual disturbances (visual field defects or enlarged blind spot), headache, tinnitus (pulsatile and non-pulsatile) and vertigo. CSF as well as ventricle volumes were determined by using an automated MRI volumetry algorithm. RESULTS: So-called 'empty sella' and optic nerve sheath distension were identified as reliable imaging signs in IIH. Posterior globe flattening turned out as a highly specific but not very sensitive sign. No abnormalities of the lateral ventricles were observed. These morphometric results could be confirmed using MR volumetry (VBM). Clinical symptoms did not correlate with an increase in lumbar opening pressure. CONCLUSIONS: Our study results indicate that lateral ventricle size is not affected in IIH. In contrast, abnormalities of the pituitary gland and optic nerve sheath were reliable diagnostic signs for IIH.

Prevalence and patterns of anatomical risk factors in patients after patellar dislocation: a case control study using MRI.

OBJECTIVE: To assess anatomical risk factors in patients after lateral patellar dislocation (LPD) and controls using MRI. METHODS: MR images of 186 knees after LPD and of 186 age- and gender-matched controls were analysed. The presence of trochlear dysplasia was assessed by evaluation of trochlear inclination, facet asymmetry, and trochlear depth; patella alta was evaluated by the Insall-Salvati index and Caton-Deschamps index; the lateralised force vector was measured by the tibial tuberosity-trochlear groove (TT-TG) distance. RESULTS: Compared with controls, dislocators had significantly lower values for all three parameters of trochlear dysplasia (-32 %, -32 %, -44 %) and significantly higher values for patella alta (+14 %,+13 %) and TT-TG (+49 %) (all P < 0.001). Trochlear dysplasia was observed in 112 dislocators (66 %), of whom 61 (36 %) additionally had patella alta and 15 (9 %) an abnormal TT-TG. As isolated risk factors, patella alta (15 %) and abnormal TT-TG (1 %) were rare. Only 25 dislocators (15 %) had no anatomical risk factors. Trochlear dysplasia in conjunction with abnormal TT-TG or patella alta is associated with a 37- and 41-fold higher risk. CONCLUSION: Most dislocators have anatomical risk factors, varying in severity and constellation.

Low-grade (WHO II) and anaplastic (WHO III) gliomas: differences in morphology and MRI signal intensities.

OBJECTIVE: To evaluate the diagnostic potential of a multi-factor analysis of morphometric parameters and signal characteristics of brain tumours and peritumoural areas for distinguishing WHO-grade II and III gliomas at magnetic resonance imaging (MRI). METHODS: MR examinations of 108 patients with histologically proven World Health Organization (WHO) grade II and III gliomas were included. Morphological criteria and MR signal characteristics were evaluated. The data were subjected to a multifactorial logistic regression analysis to differentiate between grade II and grade III gliomas. The discriminatory power was assessed by receiver operating characteristic (ROC). RESULTS: Logistic regression analysis showed that WHO grade II and III can be distinguished based on contrast enhancement, cortical involvement, margin of the enhancing lesion and maximum diameter (width and length) of the peritumoural area (the so-called tumour infiltration zone). With the final model of logistic regression analysis and with the cut-off value ≥ 0.377, WHO grade III glioma is predicted with a sensitivity of 71.0 % and a specificity of 80.4 %. CONCLUSION: Measurement of maximum diameter of peritumoural area, contrast enhancement as well as cortical involvement and the margin of the contrast-enhancing lesion can be used easily in clinical routine to adequately distinguish WHO grade II from grade III gliomas. KEY POINTS: • MRI offers new information concerning WHO-grade II and III gliomas. • The differentiation between such tumour grades is important for therapeutic decisions. • We assessed differences in enhancement, cortical involvement, margins and peritumoural appearances. • WHO grade III gliomas can be predicted with reasonable sensitivity and specificity.

Prevalence of cartilage lesions and early osteoarthritis in patients with patellar dislocation.

OBJECTIVES: Assessment of cartilage lesions and osteoarthritis (OA) of the patellofemoral joint in patients following lateral patellar dislocation using magnetic resonance imaging (MRI). METHODS: MR images of 129 knees (mean age 26 years, range 11-56) grouped as acute (A), recurrent (B), and chronic (C) dislocators were analysed regarding the prevalence and severity of patellofemoral cartilage lesions. Grades of OA were assessed using modified WORMS. RESULTS: In groups A, B, and C the prevalence of cartilage lesions was 71%, 82%, and 97%, respectively. Most lesions were located on the central patella in groups A and B (central 69% and 78%; medial 56% and 47%; lateral 31% and 42%), whereas group C revealed all regions affected (73%, 61%, and 67%). Of group A, 14% had mild OA and 64% of group B. Group C showed mild OA in 62% and moderate OA in 18%. Cartilage defect size and prevalence of OA was correlated with number of dislocations (r = 0.41 and r = 0.59; P < 0.001). CONCLUSIONS: Cartilage lesions and early OA are common after patellar dislocation and appear to increase with the frequency of dislocation. Both conditions should be considered when interpreting MRI in such patients, because of implications for treatment. KEY POINTS : • Cartilage lesions are very common after patellar dislocation. • The severity of cartilage lesions increases with number of dislocations. • Osteoarthritis is common after recurrent patellar dislocation, even in young patients. • Detecting cartilage lesions is important after patellar dislocation.

In vivo viscoelastic properties of the brain in normal pressure hydrocephalus.

Nearly half a century after the first report of normal pressure hydrocephalus (NPH), the pathophysiological cause of the disease still remains unclear. Several theories about the cause and development of NPH emphasize disease-related alterations of the mechanical properties of the brain. MR elastography (MRE) uniquely allows the measurement of viscoelastic constants of the living brain without intervention. In this study, 20 patients (mean age, 69.1 years; nine men, 11 women) with idiopathic (n = 15) and secondary (n = 5) NPH were examined by cerebral multifrequency MRE and compared with 25 healthy volunteers (mean age, 62.1 years; 10 men, 15 women). Viscoelastic constants related to the stiffness (µ) and micromechanical connectivity (α) of brain tissue were derived from the dynamics of storage and loss moduli within the experimentally achieved frequency range of 25-62.5 Hz. In patients with NPH, both storage and loss moduli decreased, corresponding to a softening of brain tissue of about 20% compared with healthy volunteers (p < 0.001). This loss of rigidity was accompanied by a decreasing α parameter (9%, p < 0.001), indicating an alteration in the microstructural connectivity of brain tissue during NPH. This disease-related decrease in viscoelastic constants was even more pronounced in the periventricular region of the brain. The results demonstrate distinct tissue degradation associated with NPH. Further studies are required to investigate the source of mechanical tissue damage as a potential cause of NPH-related ventricular expansions and clinical symptoms.

T2 mapping of the peritumoral infiltration zone of glioblastoma and anaplastic astrocytoma.

PURPOSE: To characterise peritumoral zones in glioblastoma and anaplastic astrocytoma evaluating T2 values using T2 mapping sequences. MATERIALS AND METHODS: In this study, 41 patients with histopathologically confirmed World Health Organization high grade gliomas and preoperative magnetic resonance imaging examinations were retrospectively identified and enrolled. High grade gliomas were differentiated: (a) by grade, glioblastoma versus anaplastic astrocytoma; and (b) by isocitrate dehydrogenase mutational state, mutated versus wildtype. T2 map relaxation times were assessed from the tumour centre to peritumoral zones by means of a region of interest and calculated pixelwise by using a fit model. RESULTS: Significant differences between T2 values evaluated from the tumour centre to the peritumoral zone were found between glioblastoma and anaplastic astrocytoma, showing a higher decrease in signal intensity (T2 value) from tumour centre to periphery for glioblastoma (P = 0.0049 - fit-model: glioblastoma -25.02± 19.89 (-54-10); anaplastic astrocytoma -5.57±22.94 (-51-47)). Similar results were found when the cohort was subdivided by their isocitrate dehydrogenase profile, showing an increased drawdown from tumour centre to periphery for wildtype in comparison to mutated isocitrate dehydrogenase (P = 0.0430 - fit model: isocitrate dehydrogenase wildtype -10.35±16.20 (-51) - 0; isocitrate dehydrogenase mutated 12.14±21.24 (-15-47)). A strong statistical proof for both subgroup analyses (P = 0.9987 - glioblastoma R2 0.93±0.08; anaplastic astrocytoma R2 0.94±0.15) was found. CONCLUSION: Peritumoral T2 mapping relaxation time tissue behaviour of glioblastoma differs from anaplastic astrocytoma. Significant differences in T2 values, using T2 mapping relaxation time, were found between glioblastoma and anaplastic astrocytoma, capturing the tumour centre to the peritumoral zone. A similar curve progression from tumour centre to peritumoral zone was found for isocitrate dehydrogenase wildtype high grade gliomas in comparison to isocitrate dehydrogenase mutated high grade gliomas. This finding is in accordance with the biologically more aggressive behaviour of isocitrate dehydrogenase wildtype in comparison to isocitrate dehydrogenase mutated high grade gliomas. These results emphasize the potential of mapping techniques to reflect the tissue composition of high grade gliomas.

Neuroimaging by 320-row CT: is there a diagnostic benefit or is it just another scanner? A retrospective evaluation of 60 consecutive acute neurological patients.

320-row CT enables dynamic CT angiography (4D CTA) of the entire intracranial circulation and whole-brain perfusion imaging (CTP). Sixty acute patients with neurological symptoms underwent various 320-row CT-specific protocols, including combined 4D CTA and CTP. Clinical and neuroradiological records were assessed for presumptive diagnoses, final diagnoses, supplementary and follow-up imaging studies. Additional diagnostic benefits delivered by 320-row CT were noted. Out of 60 procedures, 59 were accomplished successfully. Ischemia (n = 19), intracerebral hemorrhage (n = 7) and transient ischemic attacks (n = 10) were the major final diagnoses. Except one small cortical and two small subcortical infarctions all ischemias were diagnosed. All hemorrhages were diagnosed together with their underlying vascular pathology in five atypical cases. In conclusion, 320-row CT is a technically robust procedure being suitable for comprehensive neuroimaging of acute patients. It can provide dynamic angiographic and perfusion data of the whole brain and can deliver additional diagnostic information not available by standard CT.

Obesity and pituitary gland volume - a correlation study using three-dimensional magnetic resonance imaging.

PURPOSE: Obesity has become a major health problem and is associated with endocrine disorders and a disturbed hypothalamic-pituitary axis. The purpose of this study was to correlate pituitary gland volume determined by routine magnetic resonance imaging with patient characteristics, in particular body mass index and obesity. MATERIAL AND METHODS: A total of 144 'healthy' patients with normal findings in cerebral magnetic resonance imaging were retrospectively included. Pituitary gland volume was measured in postcontrast three-dimensional T1-weighted sequences. A polygonal three-dimensional region of interest covering the whole pituitary gland was assessed manually. Physical characteristics (gender, age, body height and body mass index) were correlated with pituitary gland volume. Multiple subgroup and regression analyses were performed. RESULTS: Pituitary gland volumes were significantly larger in females than in males (p<0.001) and young individuals (<35 years) versus middle-aged patients (35-47 years) (p=0.042). Obese patients (body mass index ≥30) had significantly larger pituitary gland volumes than overweight (250.05). Regression analysis showed that increased pituitary gland volume is associated with higher body mass index independent from gender, age and body height. CONCLUSION: Pituitary gland volume is increased in obese individuals and a high body mass index can be seen as an independent predictor of increased pituitary gland volume. Therefore, gland enlargement might be an imaging indicator of dysfunction in the hypothalamus-pituitary axis. Besides gender and age, body mass index should be considered by radiologists when diagnosing abnormal changes in pituitary gland volume.

Multivariable non-invasive association of isocitrate dehydrogenase mutational status in World Health Organization grade II and III gliomas with advanced magnetic resonance imaging T2 mapping techniques.

AIM: To investigate multivariable analyses for noninvasive association of the isocitrate dehydrogenase (IDH) mutational status in grade II and III gliomas including evaluation of T2 mapping-sequences. METHODS: Magnetic resonance imaging (MRI) examinations with histopathologically proven World Health Organization grade II and III gliomas were retrospectively enrolled. Multivariate receiver operating characteristics (ROC) analyses to associate IDH mutational status were performed containing quantitative T2 mapping analyses and qualitative characteristics (sex, age, localization, heterogeneity, oedema, necrosis and diameter). Relaxation times were calculated pixelwise by means of standardized ROI analyses. Interobserver variability also was tested. RESULTS: Out of 32 patients (mean age: 50.7 years; range: 32-83), nine had grade II gliomas and 24 grade III, while 59.5% showed a positive IDH mutated state (IDHm) and 40.5% were wildtype (IDHw). Multivariable ROC analyses were calculated for relaxation time and range, localization and age with a cumulative 0.955 area under the curve (AUC) (p < 0.001), while central T2-relaxation time had by far the highest single variable sensitivity (AUC: 0.873; range: 0.762; age: 0.809; localization: 0.713). Age (cut off: 49 years; p = 0.031) and localization (p = 0.014) were the only qualitative parameters found to be significant as IDHw gliomas were older and IDHm gliomas were preferentially located fronto-temporal. CONCLUSIONS: This is the first study evaluating quantitative T2 mapping sequences for association of the IDH mutational status in grade II and III gliomas demonstrating an association between relaxation time and mutational status. Analyses of T2 mapping relaxation times may even be suitable for predicting the correct IDH mutational state. Prognostic accuracy increases significantly in predicting the correct mutational state when combing T2 relaxation time characteristics and the qualitative MRI features age and localization.

Isotropic proton-density-weighted high-resolution MRI for volume measurement of reconstructed orbital fractures--a comparison with multislice CT.

OBJECTIVE: The cause of enophthalmos as a late complication after orbital reconstruction is poorly investigated. Multislice CT (MSCT) is usually employed for its assessment, in spite of limitations regarding soft tissue depiction/imaging, as well as the implication of radiation and production of artifacts. Magnetic resonance imaging (MRI) has been shown to be a valuable alternative. The aim of this study was to establish a bony and soft tissue orbital volume calculation method based on different high-resolution MRI sequences compared to MSCT. MATERIALS AND METHODS: Thirty-seven patients were included in this prospective study investigating the origin of enophthalmos present 3-4 months after complex orbital reconstruction. Morphological and dimensional changes of the orbit, eye globes, extraocular muscles and fat content were investigated 3-4 months after surgery. To assess the site and size of bony and soft tissue changes in the traumatized orbits, we used MSCT and MR images as well as corresponding 3-D reconstructions. RESULTS: All enophthalmic orbits revealed a significant bony volume increase compared to the contralateral side as well as a reduced sagittal eye projection. Mean orbital volume enlargements of 1.0 cm3 lead to 0.93 mm enophthalmos (P< .05). Hardly any fatty atrophy could be depicted by the different MRI techniques. CONCLUSIONS: For soft tissue depiction of the orbit, MRI was superior to MSCT. Particularly, proton density weighting proved to be the best sequence for soft tissue volume segmentation, allowing determination of the cause and degree of posttraumatic enophthalmos in reconstructed orbits.

Contrast enhanced cartilage imaging: Comparison of ionic and non-ionic contrast agents.

Our objective was to compare relaxation effects, dynamics and spatial distributions of ionic and non-ionic contrast agents in articular cartilage at concentrations typically used for direct MR arthrography at 1.5T. Dynamic MR-studies over 11h were performed in 15 bovine patella specimens. For each of the contrast agents gadopentetate dimeglumine, gadobenate dimeglumine, gadoteridol and mangafodipir trinatrium three patellae were placed in 2.5mmol/L contrast solution. Simultaneous measurements of T(1) and T(2) were performed every 30min using a high-spatial-resolution "MIX"-sequence. T(1), T(2) and DeltaR(1), DeltaR(2) profile plots across cartilage thickness were calculated to demonstrate the spatial and temporal distributions. The charge is one of the main factors which controls the amount of the contrast media diffusing into intact cartilage, but independent of the charge, the spatial distribution across cartilage thickness remains highly inhomogeneous even after 11h of diffusion. The absolute DeltaR(2)-effect in cartilage is at least as large as the DeltaR(1)-effect for all contrast agents. Maximum changes were 5-12s(-1) for DeltaR(1) and 8-15s(-1) for DeltaR(2). This study indicates that for morphologically intact cartilage only the amount of contrast agents within cartilage is determined by the charge but not the spatial distribution across cartilage thickness. In addition, DeltaR(2) can be considered for quantification of contrast agent concentrations, since it is of the same magnitude and less time consuming to measure than DeltaR(1).

Cross Sectional Imaging of Solitary Lesions of the Neurocranium.

Background Although a wide range of processes along the neurocranium are of a benign nature, there are often difficulties in the differential diagnosis. Method In the review CT/MRI scans of the head were evaluated retrospectively regarding solitary lesions along the neurocranium. The majority of the lesions were histologically proven. Results The purpose of the review is to present typical pathologies of the neurocranium and provide a systematic overview based on 12 entities, their locations, prevalence and radiological characteristics. Conclusion Processes, which primarily originate from the neurocranium have to be differentiated from secondary processes infiltrating the neurocranium. For this important diagnostic feature, MRI is typically essential, while the definitive diagnosis is often made on the basis of the medical history and the typical appearance on computer tomography. Key Points · There are often difficulties in the precise differential diagnosis of solitary lesions along the neurocranium. Typical solitary pathologies of the neurocranium based on 12 entities were presented. Both magnetic resonance imaging and computed tomography are often essential for an exact differential diagnosis.. Citation Format · Schäfer M, Koch A, Streitparth F et al. Cross Sectional Diagnosis of Solitary Lesions of the Neurocranium. Fortschr Röntgenstr 2017; 189: 1135 - 1144.