Evaluation of deep gray matter volume, cortical thickness and white matter integrity in patients with typical absence epilepsy: a study using voxelwise-based techniques.

INTRODUCTION: The objective of this study was to evaluate the cortical thickness and the volume of deep gray matter structures, measured from 3D T1-weighted gradient echo imaging, and white matter integrity, by diffusion tensor imaging (DTI) in patients with typical absence epilepsy (AE). METHODS: Patients (n = 19) with typical childhood AE and juvenile AE, currently taking antiepileptic medication, were compared with control subjects (n = 19), matched for gender and age. 3D T1 magnetization-prepared rapid gradient echo-weighted imaging and DTI along 30 noncolinear directions were performed using a 1.5-T MR scanner. FreeSurfer was used to perform cortical volumetric reconstruction and segmentation of deep gray matter structures. For tract-based spatial statistics analysis of DTI, a white matter skeleton was created, along with a permutation-based inference with 5000 permutations. A threshold of p < 0.05 was used to identify abnormalities in fractional anisotropy (FA). The mean, radial, and axial diffusivities were also projected onto the mean FA skeleton. RESULTS: Patients with AE presented decreased FA and increased mean diffusivity and radial diffusivity values in the genu and the body of the corpus callosum and right anterior corona radiata, as well as decreased axial diffusivity in the left posterior thalamic radiation, inferior cerebellar peduncle, right cerebral peduncle, and right corticospinal tract. However, there were no significant differences in cortical thickness or deep gray matter structure volumes between patients with AE and controls. CONCLUSION: Abnormalities found in white matter integrity may help to better understand the pathophysiology of AE and optimize diagnosis and treatment strategies.

Neuromyelitis optica: a diffusional kurtosis imaging study.

BACKGROUND AND PURPOSE: Conventional MR imaging typically yields normal images of the brain or indicates lesions in areas of high aquaporin expression in patients with neuromyelitis optica. Diffusional kurtosis imaging was applied in patients with neuromyelitis optica to determine whether this technique could detect alterations in diffusion and diffusional kurtosis parameters in normal-appearing white matter and to explore the relationship between diffusional kurtosis imaging and DTI parameters. MATERIALS AND METHODS: Thirteen patients with neuromyelitis optica and 13 healthy controls underwent MR imaging of the brain with conventional and diffusional kurtosis imaging sequences. Tract-based spatial statistics and region-of-interest-based analyses were conducted to identify differences between patients with neuromyelitis optica and controls through conventional DTI and diffusional kurtosis imaging parameters. The parameters were correlated to determine the potential relationship between them. RESULTS: Compared with healthy controls, several diffusional kurtosis imaging and DTI parameters were altered in various fiber tracts of patients with neuromyelitis optica (P < .05). A significant decrease (P < .05) in radial kurtosis was observed in the corpus callosum and anterior corona radiata and left optic radiation. Differences (P < .1) in mean kurtosis were found in patients with neuromyelitis optica. We found a negative correlation between diffusional kurtosis imaging (radial kurtosis, axial kurtosis, mean kurtosis) and the corresponding DTI parameters (radial diffusivity, axial diffusivity, mean diffusivity). Positive correlations were found for radial kurtosis and mean kurtosis with fractional anisotropy. CONCLUSIONS: This study demonstrated differences in conventional diffusion and diffusional kurtosis parameters, especially radial kurtosis, in the normal-appearing white matter of patients with neuromyelitis optica compared with healthy controls. Larger studies of patients with neuromyelitis optica should be performed to assess the potential clinical impact of these findings.

Virtual bronchoscopy for evaluating cervical tumors of the fetus.

We report on four cases of fetal cervical tumor, comprising three lymphangiomas and one teratoma, evaluated by ultrasound and magnetic resonance imaging (MRI) between 26 and 37 weeks' gestation. The aim was to investigate the use of virtual bronchoscopy to evaluate fetal airway patency in each case. A three-dimensional (3D) model of the airway was created from overlapping image layers generated by MRI. The files obtained were manipulated using 3D modeling software, allowing the virtual positioning of observation cameras, adjustment of lighting parameters and creation of simulated 3D movies for analysis of a virtual path through the model. In all fetuses, fetal airway patency was clearly demonstrated by virtual bronchoscopy and this was confirmed postnatally. MRI with virtual bronchoscopy could become a useful tool for studying fetal airway patency in cases of cervical tumor.

Pseudoprogression and pseudoresponse: imaging challenges in the assessment of posttreatment glioma.

The current standard of care for newly diagnosed cases of high-grade glioma is surgical resection followed by RT with concurrent chemotherapy. The most widely used criteria for assessing treatment response are based on a 2D measurement of the enhancing area on MR imaging known as the Macdonald Criteria. Recently, nontumoral increases (pseudoprogression) and decreases (pseudoresponse) in enhancement have been found, and these can confuse outcome evaluation. Here we review pseudoprogression and pseudoresponse and describe how better understanding of these phenomena can aid interpretation.

Additive manufacturing models of fetuses built from three-dimensional ultrasound, magnetic resonance imaging and computed tomography scan data.

OBJECTIVE: To generate physical fetal models using images obtained by three-dimensional ultrasonography (3DUS), magnetic resonance imaging (MRI) and computed tomography (CT) to guide additive manufacturing technology. METHODS: Images from 33 fetuses, including three sets of twins, were used. Fifteen fetuses were normal and evaluated only by 3DUS. Eighteen cases had abnormalities such as conjoined twins, tumors, aneuploidy, skeletal abnormalities, central nervous system abnormalities and facial or thoracic defects. Scans were performed using high-resolution 3DUS. In cases of abnormalities, MRI and CT were performed on the same day as 3DUS. The images obtained with 3DUS, CT or MRI were exported to a workstation in DICOM format. A single observer performed slice-by-slice manual segmentation using a digital high-definition screen. Software that converts medical images into numerical models was used to construct virtual 3D models, which were physically realized using additive manufacturing technologies. RESULTS: Physical models based on 3DUS, MRI and CT images either separately or combined were successfully generated. They were remarkably similar to the postnatal appearance of the aborted fetus or newborn baby, especially in cases with pathology. CONCLUSION: The use of 3DUS, MRI and CT may improve our understanding of fetal anatomical characteristics, and these technologies can be used for educational purposes and as a method for parents to visualize their unborn baby. The images can be segmented and applied separately or combined to construct 3D virtual and physical models.

Case report. Atlantoaxial synovial cyst causing isolated unilateral hypoglossal nerve paralysis.

Cervical synovial cysts are rare entities that are, most of the time, asymptomatic. They can cause nerve root or spinal cord compression, especially when acute haemorrhage or a marked increase in size occurs. Isolated unilateral hypoglossal nerve paralysis caused by compression of its cisternal segment is also an extremely rare condition. We report the case of a 51-year-old woman who presented with dysarthria and tongue fasciculation. MRI revealed an atlantoaxial synovial cyst that extended cranially through the hypoglossal canal and compressed the fibres of the left XII nerve on its cisternal segment. To our knowledge, this is the first case report of XII nerve paralysis being caused by an atlantoaxial synovial cyst.

Myocardial delayed enhancement in patients with pulmonary hypertension and right ventricular failure: evaluation by cardiac MRI.

In this study, we evaluated patients with pulmonary arterial hypertension (PAH) and impaired right ventricular function. We used cardiac MRI for the detection of myocardial delayed enhancement (MDE) and its possible association with other clinical variables. 20 patients (6 males and 14 females, aged 44.5+/-11 years; 15 New York Heart Association class III, 5 class IV) with known PAH (13 idiopathic, 7 resulting from chronic pulmonary embolism) were evaluated for the detection of MDE. Short-axis cine images of the heart were made for ventricular function assessment using a steady-state free precession sequence. For MDE evaluation, a short-axis phase-sensitive inversion recovery sequence was performed 10 min after intravenous administration of 0.2 mmol kg(-1) gadodiamide. Right ventricle (RV) systolic dysfunction, RV enlargement and RV hypertrophy were present in 20 patients (RV ejection fraction, 21.5+/-7.2%; RV diastolic diameter, 5.97+/-0.79 cm; RV wall thickness, 0.73+/-0.10 cm). 13 of the 20 patients (65%) were positive for MDE (10 anterior, 12 inferior). All 13 positive patients with MDE demonstrated small hyperintense areas at the insertion points of the RV free wall in the interventricular septum. We found no significant correlation between MDE and ejection fraction or other haemodynamic variables. In this study, MDE correlated positively only with the duration of disease. We found that septal MDE can be present in patients with PAH and impaired ventricular function. However, further studies are necessary to investigate this possible association and its prognostic implication.

Infra-renal abdominal aorta agenesis: a case report with emphasis on MR angiography findings.

The purpose of this study is to report a case of infra-renal aorta agenesis with emphasis on the MR angiography (MRA) findings. A 66-year-old woman presented with urinary complaints. Pelvic and abdominal ultrasound showed hydronephrosis secondary to ureteral lithiasis; the distal portion of the abdominal aorta was not identified. Abdominal CT showed that the infra-renal portion of the abdominal aorta was apparently absent. MRI and MRA demonstrated that, after the origin of the renal arteries, the abdominal aorta spontaneously terminated in two lumbar hypertrophic arteries. In addition, MRA showed a dilated superior mesenteric artery that formed a vascular loop, which continued posterior and inferiorly towards the posterior pelvic region. In this region, it bifurcated and formed internal iliac branches, which were responsible for the arterial supply of the pelvis. In conclusion, MRA allows for precise evaluation of patients with infra-renal abdominal aorta agenesis. Although it is a rare entity, radiologists should be able to recognize it in ultrasound, CT and MRI studies.

Susceptibility-weighted imaging for the evaluation of patients with familial cerebral cavernous malformations: a comparison with t2-weighted fast spin-echo and gradient-echo sequences.

BACKGROUND AND PURPOSE: The T2-weighted gradient-echo (GRE) imaging is currently the gold standard MR imaging sequence for the evaluation of patients with cerebral cavernous malformation (CCM) lesions. We aimed to compare the sensitivity of susceptibility-weighted imaging (SWI) with T2-weighted fast spin-echo (FSE) and GRE imaging in assigning the number of CCM lesions in patients with the familial form of the disease. MATERIALS AND METHODS: We studied 15 patients (8 men, 7 women; mean age, 34 years) with familial CCM. All patients underwent MR imaging with the following sequences: T1-weighted spin echo, T2-weighted FSE, T2-weighted GRE, and SWI. Two neuroradiologists read the images regarding the number of lesions seen on each sequence. The final decisions were reached by consensus. The number of lesions on the different sequences was compared with analysis of variance, followed by a nonparametric Wilcoxon matched-pairs signed rank test. RESULTS: The number of lesions was higher on T2-weighted GRE than on T2-weighted FSE (P = .001). In addition, more lesions were seen on SWI than on T2-weighted GRE (P = .001) and FSE (P = .001) sequences. CONCLUSION: The sensitivity of SWI in assigning the number of CCM lesions in patients with the familial form of the disease is significantly higher than that of T2-weighted FSE and GRE sequences.

Pulmonary and cardiac cysticercosis: helical CT findings.

The authors aim to report the chest CT findings of a patient with disseminated cysticercosis, emphasising the pulmonary and cardiac features. The main finding consisted of multiple pulmonary, cardiac and chest wall nodules. The present case demonstrates that cysticercosis should be considered in the differential diagnosis of multiple pulmonary nodules, mainly in those patients with similar lesions in the cardiac muscle and/or in the chest wall.