Huishu Yuan

Diffusion Tensor Imaging Study of the Anterior Limb of Internal Capsules in Neuroleptic-Naive Schizophrenia

RATIONALE AND OBJECTIVES Abnormalities in brain structure have been implicated in psychosis. Herein, we investigated the differences in fractional anisotropy (FA) and average diffusion coefficient (ADC) in the bilateral anterior limb of internal capsules between neuroleptic-naive schizophrenic patients and appropriately matched healthy controls. MATERIALS AND METHODS Magnetic resonance imaging was performed with a 1.5 T superconductive MR scanner, and diffusion tensor imaging was carried out in 21 neuroleptic-naive schizophrenic patients and 18 matched healthy controls. FA and ADC were measured by region of interest analysis. RESULTS Compared with healthy controls, the neuroleptic-naive schizophrenic patients showed significantly reduced FA in the bilateral anterior limb of the internal capsule. However, the difference in the ADC values between the patients and the controls was not significant. CONCLUSIONS FA of the bilateral anterior limb of the internal capsule was reduced in neuroleptic-naive schizophrenic patients, indicating that the integrity of the white matter of the bilateral thalamus-frontal connection or the bilateral thalamus-anterior cingulate gyrus connection was destroyed.

Differentiation of myeloma and metastatic cancer in the spine using dynamic contrast-enhanced MRI

Spinal myeloma and metastatic cancer cause similar symptoms and show similar imaging presentations, thus making them difficult to differentiate. In this study, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed to differentiate between 9 myelomas and 22 metastatic cancers that present as focal lesions in the spine. The characteristic DCE parameters, including the peak signal enhancement percentage (SE%), the steepest wash-in SE% during the ascending phase and the wash-out SE%, were calculated by normalizing to the precontrast signal intensity. The two-compartmental pharmacokinetic model was used to obtain K(trans) and kep. All nine myelomas showed the wash-out DCE pattern. Of the 22 metastatic cancers, 12 showed wash-out, 7 showed plateau, and 3 showed persistent enhancing patterns. The fraction of cases that showed the wash-out pattern was significantly higher in the myeloma group than the metastatic cancer group (9/9=100% vs. 12/22=55%, P=.03). Compared to the metastatic cancer group, the myeloma group had a higher peak SE% (226%±72% vs. 165%±60%, P=.044), a higher steepest wash-in SE% (169%±51% vs. 111%±41%, P=.01), a higher K(trans) (0.114±0.036 vs. 0.077±0.0281/min, P=.016) and a higher kep (0.88±0.26 vs. 0.49±0.23 1/min, P=.002). The receiver operating characteristic analysis to differentiate between these two groups showed that the area under the curve was 0.798 for K(trans), 0.864 for kep and 0.919 for combined K(trans) and kep. These results show that DCE-MRI may provide additional information for making differential diagnosis to aid in choosing the optimal subsequent procedures or treatments for spinal lesions.

A multi-resolution approach for spinal metastasis detection using deep Siamese neural networks

Spinal metastasis, a metastatic cancer of the spine, is the most common malignant disease in the spine. In this study, we investigate the feasibility of automated spinal metastasis detection in magnetic resonance imaging (MRI) by using deep learning methods. To accommodate the large variability in metastatic lesion sizes, we develop a Siamese deep neural network approach comprising three identical subnetworks for multi-resolution analysis and detection of spinal metastasis. At each location of interest, three image patches at three different resolutions are extracted and used as the input to the networks. To further reduce the false positives (FPs), we leverage the similarity between neighboring MRI slices, and adopt a weighted averaging strategy to aggregate the results obtained by the Siamese neural networks. The detection performance is evaluated on a set of 26 cases using a free-response receiver operating characteristic (FROC) analysis. The results show that the proposed approach correctly detects all the spinal metastatic lesions while producing only 0.40 FPs per case. At a true positive (TP) rate of 90%, the use of the aggregation reduces the FPs from 0.375 FPs per case to 0.207 FPs per case, a nearly 44.8% reduction. The results indicate that the proposed Siamese neural network method, combined with the aggregation strategy, provide a viable strategy for the automated detection of spinal metastasis in MRI images.

Microstructural white matter abnormalities independent of white matter lesion burden in amnestic mild cognitive impairment and early Alzheimer disease among Han Chinese elderly.

This study was designed to evaluate the microstructural integrity of white matter (WM) in amnestic mild cognitive impairment (MCI) and Alzheimers disease (AD) among Han Chinese elderly using diffusion tensor imaging (DTI) technique, and to investigate the relationship between WM abnormalities and cognitive dysfunction. Sixty-four subjects (23 mild probable AD, 20 amnestic MCI, and 21 age-matched normal controls) who did not have visible WM lesion burden were analyzed. Fractional anisotropy (FA) and mean diffusivity were measured in normal-appearing WM (NAWM) using DTI with 64 encoding directions. The results were correlated with the scores of Mini-Mental State Examination (MMSE) and Cognitive Ability Screening Instrument (CASI). Statistical analysis showed the FA value in parietal WM was significantly lower in MCI compared to NC (P<0.001), and further decreased in AD compared to MCI (P=0.005). The lower FA and elevated mean diffusivity values were found in temporal WM, frontal WM, parahippocampal and posterior cingulate fibers of AD group compared to MCI and NC (all P<0.01). Canonical correlation analysis showed that the parietal FA values measured from all subjects were significantly correlated with the scores of CASI and MMSE (P<0.01). The results indicated that DTI can detect microstructural WM abnormalities in AD and amnestic MCI, and the measures were correlated with cognitive performance. In MCI, the abnormality was found to be limited within the parietal WM; and in AD a more widespread alteration was found in other brain regions as well.

Morphological and dynamic contrast enhanced MR imaging features for the differentiation of chordoma and giant cell tumors in the Axial Skeleton.

To characterize the morphological and dynamic‐contrast‐enhanced (DCE) MRI features of chordoma and giant cell tumor (GCT) of bone occurring in the axial skeleton.

Different post label delay cerebral blood flow measurements in patients with Alzheimer's disease using 3D arterial spin labeling

PURPOSE To evaluate cerebral blood flow (CBF) in patients with Alzheimers disease (AD) using a three-dimensional pseudocontinuous arterial spin labeling (PCASL). We aimed to study the effects of different post label delay on the resulting CBF maps and to investigate the characteristics and clinical applications of brain perfusion. MATERIALS AND METHODS Sixteen AD patients and nineteen healthy control subjects were recruited. 3D PCASL was performed using a 3.0 T MR scanner. ASL was performed twice with different post label delays (PLD). Comparisons of CBF were made between AD patients and healthy control subjects respectively with PLD of 1.5 s and PLD of 2.5 s. Relationship between the CBF values and cognition was investigated using correlation analysis. A receiver operating characteristic (ROC) curve was generated for CBF measurements in posterior cingulate region. RESULT AD patients with PLD of 1.5 s showed lower CBF values primarily in bilateral temporal lobes, precuneus, middle and posterior cingulate gyri, left inferior parietal gyrus, left angular gyrus and left superior frontal gyrus. Lowered cerebral values were also observed in similar regions with PLD of 2.5 s, but the clusters of voxel were smaller. CBF values were associated with cognition scores in most of gyri mentioned above. CONCLUSION Hypoperfusion areas were observed in AD patients. PLD of 1.5s was sufficient to display CBF. Considering the complicated AD pathology, multiple PLDs are strongly recommended.

Assessment of porosity index of the femoral neck and tibia by 3D ultra‐short echo‐time MRI

To measure the porosity index (PI) by ultrashort echo‐time magnetic resonance imaging (UTE MRI) of the femoral neck and tibia; assess its correlations with age, gender, and body mass index (BMI); and analyze the PI correlations between both sites to assess whether tibial PI can reflect changes of femoral neck PI.

Solitary fibrous tumour of the spine: imaging features of a commonly misdiagnosed entity

ObjectiveSolitary fibrous tumours (SFTs) occurring in the spine are rare. Herein, we review the clinical and imaging data of spinal SFT.MethodsWe retrospectively analysed eight cases of pathologically confirmed spinal SFT imaging and clinical data, pathological manifestations, surgical methods, and follow-up results.ResultsFive SFTs cases occurred in the cervical spine, two in the thoracic spine, and one in the lumbosacral spine. Five cases showed a dumbbell-shaped or lobulated soft tissue mass that grew across the intervertebral foramen, two cases showed an expansive intraosseous mass formation in the vertebral body and/or posterior element, and one case showed a long-spindle shaped intraspinal canal mass growing along the spinal canal. Seven caused local invasion and destruction of the vertebral body and posterior element. Benign SFTs displayed a good prognosis, whereas malignant SFTs were prone to recurrence and metastasis (3/4).ConclusionSpinal SFTs are difficult to characterise with imaging and required pathological and immunohistochemical investigation. Prolonged follow-up is recommended once a diagnosis of spinal SFTs has been established because of the unclear biology.Key Points• Spinal solitary fibrous tumours are extremely rare.• SFTs should be showed the differential of masses developing though the foramen.• Combing imaging with pathology and immunochemistry assesses the diagnosis and establish nature.

Spinal cellular schwannoma: An analysis of imaging manifestation and clinicopathological findings

OBJECTIVES Cellular schwannoma that occurs in the spine is relatively rare. Herein, we retrospectively analyzed the clinical and imaging data from nine cases of spinal cellular schwannoma. MATERIALS AND METHODS The clinical, imaging data and pathological manifestations were retrospectively analyzed from nine cases of pathologically confirmed spinal cellular schwannoma. RESULTS All nine cases were treated with surgical excision; seven cases were solitary lesions characterized by a dumbbell-shaped soft tissue mass growing out across the intervertebral foramen and two cases were multiple nodular lesions in the spinal canal. Six cases had compressive bony destruction, one case displayed osteolytic and compressive bony destruction, and two cases were without apparent bony destruction. Computed Tomography (CT)scans showed three cases were isodense and two cases were miscellany density. Magnetic Resonance Imaging (MRI) scans showed that the solid part of the tumor was isointense on the T1-weighted imaging (T1WI); five cases were isointense and three cases were slightly hyperintense on T2-weighted imaging (T2WI). Five cases exhibited hyperintense cystic regions. MRI enhanced scanning showed that 3/7 cases showed moderately to markedly heterogeneous enhancement and the remaining 4/7 cases showed markedly homogeneous enhancement. Except for one recurrence, 8/9 cases had a good prognosis. CONCLUSION Spinal cellular schwannoma should be diagnosed combining the imaging manifestation with clinical performance and pathological examination in order to distinguish it from other tumors, such as classical schwannoma and malignant peripheral nerve sheath tumors.