Target Density Effects on Charge Transfer of Laser-Accelerated Carbon Ions in Dense Plasma.

We report on charge state measurements of laser-accelerated carbon ions in the energy range of several MeV penetrating a dense partially ionized plasma. The plasma was generated by irradiation of a foam target with laser-induced hohlraum radiation in the soft x-ray regime. We use the tricellulose acetate (C_{9}H_{16}O_{8}) foam of 2 mg/cm^{3} density and 1 mm interaction length as target material. This kind of plasma is advantageous for high-precision measurements, due to good uniformity and long lifetime compared to the ion pulse length and the interaction duration. We diagnose the plasma parameters to be T_{e}=17 eV and n_{e}=4×10^{20} cm^{-3}. We observe the average charge states passing through the plasma to be higher than those predicted by the commonly used semiempirical formula. Through solving the rate equations, we attribute the enhancement to the target density effects, which will increase the ionization rates on one hand and reduce the electron capture rates on the other hand. The underlying physics is actually the balancing of the lifetime of excited states versus the collisional frequency. In previous measurement with partially ionized plasma from gas discharge and z pinch to laser direct irradiation, no target density effects were ever demonstrated. For the first time, we are able to experimentally prove that target density effects start to play a significant role in plasma near the critical density of Nd-glass laser radiation. The finding is important for heavy ion beam driven high-energy-density physics and fast ignitions. The method provides a new approach to precisely address the beam-plasma interaction issues with high-intensity short-pulse lasers in dense plasma regimes.

[Evaluation of Crohn's disease activity with multi-slice CT enterography].

OBJECTIVE: To discuss the diagnostic value of Crohn's disease activity with multi-slice CT enterography. METHODS: MSCTE examination data of 88 cases of CD patients by clinical, endoscopy, pathology confirmed in Sir Run Run Shaw Hospital from January 2013 to June 2014 were analysed. According to the Harvey-Bradshaw index, all of CD patients were divided into the active phase group and remission phase group. Imaging findings of two groups were compared. To explore the relationship between MSCTE findings and CRP/ESR of CD patients. RESULTS: The wall thickness (8.2 ± 2.6) mm and enhancement degree (112 ± 16) HU in active phase group were higher than the wall thickness (5.4 ± 1.6) mm and enhancement degree (93 ± 17) HU in the remission phase group (P < 0.01). The incidences of intestinal wall stratification enhancement, comb sign, swollen lymph nodes, phlegmon, intestinal fistula, intestinal stenosis in active phase group (88.5%, 72.1%, 77%, 45.9%, 26.2%, 65.6%) were significantly higher than those in remission phase group (29.6%, 18.5%, 25.9%, 0, 3.7%, 37%) (P < 0.05). The incidences of intestinal wall homogeneous enhancement in remission phase group (70.4%) were higher than those in active phase group (11.5%) (P < 0.01). There was no significant difference in the incidences of abscesse in two groups (P > 0.05). CRP was correlated with the wall thickness and enhancement degree, abnornlal mesentery vascularity, lymph node enlargement, phlegmon, intestinal fistula (r > 0.2, P < 0.05). ESR was correlated with the wall enhancement degree, abnormal mesentery vascularity, lymph node enlargement and phlegmon (r > 0.2, P < 0.05). CONCLUSION: CT enterography can adequately demonstrate mural abnormalities and assess the presence of extramural complications, which are helpful in evaluating the activity of Crohn's disease.

A multicenter clinical AI system study for detection and diagnosis of focal liver lesions.

Early and accurate diagnosis of focal liver lesions is crucial for effective treatment and prognosis. We developed and validated a fully automated diagnostic system named Liver Artificial Intelligence Diagnosis System (LiAIDS) based on a diverse sample of 12,610 patients from 18 hospitals, both retrospectively and prospectively. In this study, LiAIDS achieved an F1-score of 0.940 for benign and 0.692 for malignant lesions, outperforming junior radiologists (benign: 0.830-0.890, malignant: 0.230-0.360) and being on par with senior radiologists (benign: 0.920-0.950, malignant: 0.550-0.650). Furthermore, with the assistance of LiAIDS, the diagnostic accuracy of all radiologists improved. For benign and malignant lesions, junior radiologists' F1-scores improved to 0.936-0.946 and 0.667-0.680 respectively, while seniors improved to 0.950-0.961 and 0.679-0.753. Additionally, in a triage study of 13,192 consecutive patients, LiAIDS automatically classified 76.46% of patients as low risk with a high NPV of 99.0%. The evidence suggests that LiAIDS can serve as a routine diagnostic tool and enhance the diagnostic capabilities of radiologists for liver lesions.

Analysis of degradation kinetic modeling and mechanism of chlorinated-halonitromethanes under UV/monochloramine treatment.

Chlorinated-halonitromethanes (Cl-HNMs) including chloronitromethane (CNM), dichloronitromethane (DCNM), and trichloronitromethane (TCNM) are nitrogenous disinfection by-products, which have high cytotoxicity and genotoxicity to human. This study aimed to investigate the degradation kinetic modeling and mechanism of Cl-HNMs under monochloramine activated by ultraviolet of 254 nm (UV/NH2Cl) treatment. The first-principle kinetic model of UV/NH2Cl process was developed to simulate Cl-HNMs degradation. Of note, the second-order rate constants of Cl-HNMs reacting with HO• (∼108 M-1 s-1), Cl• (kCl•,CNM or DCNM = âˆ¼1010 M-1 s-1, kCl•,TCNM = âˆ¼102 M-1 s-1), Cl2•- (kCl•,CNM or DCNM = âˆ¼109 M-1 s-1, kCl•,TCNM = âˆ¼101 M-1 s-1), ClO• (∼105-106 M-1 s-1) and CO3•- (∼106-107 M-1 s-1) were obtained by the first-principle kinetic model. Overall, Cl-HNMs degradation under UV/NH2Cl treatment was successfully predicted by the kinetic model under various conditions. It was found that UV (>60%) was dominant in Cl-HNMs degradation, followed by HO• (3.8%-24.5%), reactive chlorine species (RCS, 0.9%-28.8%) and CO3•- (0-26.1%). Among the contributions of RCS, Cl• and Cl2•- were main radicals in the degradation of CNM and DCNM, while ClO• was responsible for the abatement of TCNM. The minimum EE/O values under UV/NH2Cl treatment were approximately 30% lower than those under UV treatment. Finally, the possible degradation pathways were proposed, including hemolytic/heterolytic cleavage of Cl-HNMs by UV irradiation, hydrogen abstraction/electron transfer of CNM and DCNM and adduct reaction of TCNM by free radicals. This study based on the kinetic model is beneficial to predict and control the concentrations of Cl-HNMs under UV/NH2Cl treatment.

An Unsupervised 3D Image Registration Network for Brain MRI Deformable Registration.

In recent years, deep learning has made successful applications and remarkable achievements in the field of medical image registration, and the method of medical image registration based on deep learning has become the current research hotspot. However, the performance of convolutional neural networks may not be fully exploited due to neglect of spatial relationships between distant locations in the image and incomplete updates of network parameters. To avoid this phenomenon, MHNet, a multiscale hierarchical deformable registration network for 3D brain MR images, was proposed in this paper. This network was an unsupervised end-to-end convolutional neural network. After training, the dense displacement vector field can be predicted almost in real-time for the unseen input image pairs, which saves a lot of time compared with the traditional algorithms of independent iterative optimization for each pair of images. On the basis of the encoder-decoder structure, this network introduced the improved Inception module for multiscale feature extraction and expanding the receptive field and the hierarchical forecast structure to promote the update of the parameters of the middle layers, which achieved the best performance on the augmented public dataset compared with the existing four excellent registration methods.

Undifferentiated carcinoma of the pancreas with osteoclast like giant cells: Literature review with CT/MR imaging findings in 3 cases.

Undifferentiated carcinoma with osteoclast-like giant cells of pancreas (UCOGCP) is a relatively rare tumor worldwide. Its accurate preoperative diagnosis is extremely difficult. Because the mass is usually large and closely related to neighboring structures, it is difficult to locate the tumor and it is often misdiagnosed as pancreatic cancer, neuroendocrine tumor or gastrointestinal stromal tumor. Combining literature to analyze UCOGCP clinical features (including age of onset, prevalent location) and imaging features (including lesion size, mass nature), to explore the value of preoperative CT and MRI in the diagnosis and differential diagnosis of UCOGCP and hope to help clinical diagnosis and treatment.

Development of nanoparticle-based magnetic resonance colonography.

This study was to develop a novel method of nanoparticle-based MR colonography. Two types of solid lipid nanoparticles (SLNs) were synthesized with loading of (a) gadolinium (Gd) diethylenetriaminepenta acetic acid to construct Gd-SLNs as an MR T1 contrast agent and (b) otcadecylamine-fluorescein-isothiocyanate to construct Gd-fluorescein isothiocyanate (FITC)-SLNs for histologic confirmation of MR findings. Through an in vitro experiment, we first evaluated the size distribution and gadolinium diethylenetriaminepenta acetic acid entrapment efficiency of these SLNs. The SLNs displayed a size distribution of 50-300 nm and a gadolinium diethylenetriaminepenta acetic acid entrapment efficiency of 56%. For in vivo validation, 30 mice were divided into five groups, each of which was administered a transrectal enema using: (i) Gd-SLNs (n=6); (ii) Gd-FITC-SLNs (n=6); (iii) blank SLNs (n=6); (iv) gadolinium diethylenetriaminepenta acetic acid (n=6); and (v) water (n=6). T1-weighted fluid-attenuated inversion-recovery MRI was then performed on mice after transrectal infusion of Gd-SLNs or Gd-FITC-SLNs, which demonstrated bright enhancement of the colonic walls, with decrease in T1 relaxation time. When Gd-FITC-SLNs were delivered, green fluorescent spots were visualized in both the extracelluar space and the cytoplasm through colonic walls under confocal microscopy and fluorescence microscopy. This study establishes the "proof-of-principle" of a new imaging technique, called "nanoparticle-based MR colonography," which may provide a useful imaging tool for the diagnosis of colorectal diseases.

A Medical Image Registration Method Based on Progressive Images.

BACKGROUND: Medical image registration is an essential task for medical image analysis in various applications. In this work, we develop a coarse-to-fine medical image registration method based on progressive images and SURF algorithm (PI-SURF) for higher registration accuracy. METHODS: As a first step, the reference image and the floating image are fused to generate multiple progressive images. Thereafter, the floating image and progressive image are registered to get the coarse registration result based on the SURF algorithm. For further improvement, the coarse registration result and the reference image are registered to perform fine image registration. The appropriate progressive image has been investigated by experiments. The mutual information (MI), normal mutual information (NMI), normalized correlation coefficient (NCC), and mean square difference (MSD) similarity metrics are used to demonstrate the potential of the PI-SURF method. RESULTS: For the unimodal and multimodal registration, the PI-SURF method achieves the best results compared with the mutual information method, Demons method, Demons+B-spline method, and SURF method. The MI, NMI, and NCC of PI-SURF are improved by 15.5%, 1.31%, and 7.3%, respectively, while MSD decreased by 13.2% for the multimodal registration compared with the optimal result of the state-of-the-art methods. CONCLUSIONS: The extensive experiments show that the proposed PI-SURF method achieves higher quality of registration.

[White matter tractography by diffusion tensor imaging in prognosis of acute lacunar infarctions].

OBJECTIVE: To evaluate diffusion tensor tractography (DTT) of white matter in prognosis of acute lacunar infarctions. METHODS: Twenty-eight patients of pyramidal tract strokes at the acute phase (<3 days) with a marked motor defect were examined. Lesions were identified on diffusion weighted imaging and isotropic imaging of DTI, and infarctions and the tract were shown on the DTT images simultaneously. The anatomic location and pattern of the lesions were visualized on DTT, with regard of the corticospinal tract (CST), all patients were divided into three clinical subgroups: in Group 1 infarction lesions were close to CST, in Group 2 CST was partial involved, in Group 3 lesions centered in the pyramidal tract. Subsequently, they were compared with the National Institutes of Health Stroke Scale (NIHSS) scores at acute phase (<3 days), early chronic phase (8 approximately 14 days), and outcome(30 approximately 60 days). RESULT: NIHSS scores of Group 1(12/28) were not different with those of Group 2 (11/28) at the acute phase (U=-1.430, P>0.05), and NIHSS scores in Group 2 were significantly lower than those of Group 3(5/28) (U= -2.676, P <0.01). In the outcome, NIHSS scores of Group 1 were significantly lower than those of Group 2 (U= -2.501, P<0.05), NIHSS scores of Group 2 were significantly lower than those of Group 3 (U= -2.948, P<0.01). Among these three groups,Group 1 all had good recovery, Group 2 also had good recovery but sometimes with some mild motor disfunction, and Group 3 always had marked defect and minor improvement. Both rADC value and rFA value were induced in the acute lacunar infarctions. CONCLUSION: DTT is helpful in prognestic valuation of acute lacunar infarction by providing visualized stereo localization of CST and infarction lesions.

Chronic enteropathy associated with SLCO2A1 gene: A case report and literature review.

A case of chronic enteropathy associated with SLCO2A1 gene (CEAS) is presented. The female patient was readmitted four times during a three-year follow-up period for intractable dropsy and anemia. Multiple ulcers of small bowel wall were revealed by endoscopic examination. Computed tomography enterography (CTE) and magnetic resonance enterography (MRE) showed the segmental wall thickening of the small bowel. Hepatosplenomegaly and increased bone density of spine and pelvis suggested the diagnosis of myelofibrosis. X-ray films showed the cortical thickening of tibiofibula. The mutations of SLCO2A1 gene were revealed by gene test and the diagnosis of CEAS was confirmed. According to our case report, imaging examinations, including CTE, MRE and X-ray films provide additional valuable information during the diagnostic procedure of CEAS.

Bilateral internal carotid artery agenesis with artery compression of the brain parenchyma.

Bilateral internal carotid artery (ICA) agenesis is an extremely rare congenital anomaly. The most common type of collateral circulation is developed through the circle of Willis via the basilar and posterior communicating arteries. Both anterior circulations are usually supplied by enlarged posterior communicating arteries (PCOMs). We present an unusual case of bilateral ICA agenesis, which is associated with dolichoectatic left PCOM and left posterior cerebral artery (PCA) compression of left basal ganglia and thalamus. These complex cerebral and vascular anomalies can be noninvasively revealed and evaluated by CT and MR.

Coexistence of small cell neuroendocrine carcinoma and villous adenoma in the ampulla of Vater.

Small cell neuroendocrine carcinoma of the ampulla of Vater is extremely rare and different from the common ampullary adenocarcinoma. The ampullary adenoma is also a rare neoplasm and has the potential to develop an adenocarcinoma. Their coexistence has been rarely reported in the literature. We herein describe an unusual case of a small cell neuroendocrine carcinoma associated with a villous adenoma in the ampulla of Vater with emphasis on computed tomography (CT) and histopathological findings. We also discuss their clinical, histopathological and radiological features as well as possible histogenesis.

Application of turbo fluid-attenuated inversion-recovery MRI in evaluation of intraspinal tumors.

PURPOSE: Although fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI) is widely applied to diagnose central nervous system diseases, its role in diagnosis of intraspinal tumors is unclear. In this study, we evaluated the potential clinical application of a turbo FLAIR sequence for imaging of intraspinal tumors. MATERIALS AND METHODS: Forty-eight consecutive patients with intraspinal tumors underwent MRI with turbo FLAIR and turbo spinal echo (TSE) sequences. Turbo FLAIR images were then qualitatively and quantitatively compared with T2-weighted TSE images. RESULTS: Turbo FLAIR images were evaluated as superior to T2-weighted TSE images for image artifact, extradural tumor conspicuity, and intradural extramedullary tumor conspicuity and detection. Intramedullary tumor conspicuity with turbo FLAIR was less than T2-weighted TSE. Similar capabilities in detection of extradural and intramedullary tumors were found between turbo FLAIR and T2-weighted TSE. Turbo FLAIR and T2-weighted TSE displayed similar normal spinal cord signal-noise ratio (SNR) and tumor-to-cerebrospinal fluid (CSF) contrast-to-noise ratio (CNR). In addition, turbo FLAIR yielded significantly higher tumor-to-CSF contrast than T2-weighted TSE. However, tumor SNR, tumor-to-normal spinal cord contrast and CNR with turbo FLAIR images were lower than those with T2-weighted TSE images. CONCLUSION: This study demonstrated (a) a superiority of turbo FLAIR to T2-weighted TSE in displaying and detecting intradural extramedullary tumors, (b) a superiority of turbo FLAIR to T2-weighted TSE in demonstrating extradural tumors, and (c) less usefulness in displaying intramedullary tumors with turbo FLAIR than with T2-weighted TSE.

[Functional MRI study on thalamus activation induced by electrical stimulation of different intensities].

OBJECTIVE: To detect the activation pattern of the thalamus in human by the functional magnetic resonance imaging (fMRI) with the electrical stimulation of different intensities, and to explore the mechanism of this area in pain modulation. METHODS: Ten healthy right-handed volunteers were given different electrical stimulations of 1-, 2-, and 3- times pain threshold respectively. The whole-brain was scanned simultaneously by GE 1.5T magnetic resonance imaging system. The data were postprocessed by analysis of functional neuroimages (AFNI) to establish the regional activity maps of the thalamus. RESULTS: Patterns of functional activity showed a positive linear relationship between the activation signals and stimulation intensity in bilateral thalamus, whereas the BOLD signal of bilateral medial thalamus demonstrated that the curve was similar to the exponential function. Meanwhile, the activation in the contralateral lateral thalamus (cThl), but not the contralateral medial thalamus (cThm), was prominent compared with the corresponding ipsilateral subregions, and only the lateral thalamus displayed a contralateral biased representation while the medial thalamus lacked this property. CONCLUSION: Thalamus is one of the vital components in the pain modulation network, which can present spatial segregation activations with unique characteristics of stimulation intensity-response in each subregion. All the results are helpful to understand the crucial role of thalamus in processing the pain information.

[The value of spiral computed tomography in diagnosis of adult intussusception].

OBJECTIVE: To evaluate the value of spiral computed tomography (CT) in diagnosis of adult intussusception. METHODS: Sixty-eight patients with adult intussusception, 42 males and 28 females, aged 52.5 (30-82), with the course of 3 days-13 months, underwent plain CT scanning and biphase CT enhanced scanning of the abdomen. Operation was performed later. RESULTS: Sixty-six of the 68 patients (97.1%) were diagnosed as with intussusception by spiral CT. Direct signs of intussusception were shown in 66 patients: concentric circle sign in 66 cases, vessel involvement in 61 cases, and fat sign in 58 cases. And main indirect signs were shown in 19 cases: ring sign in 19 cases, ileus sign in 24 cases, and ascitic fluid sign in 4 cases. Other signs included mesenteric infiltration in 4 cases and retroperitoneal lymphadenectasis in 8 cases. Operation performed later showed an accurate rate of etiological diagnosis of intussusception by CT of 72.1%. CONCLUSION: Spiral CT has important value in diagnosis of adult intussusception and its etiology. The specific signs to diagnose adult intussusception are concentric circle sign, vessel involvement and fat sign.

The activation of the cortical hand area by toe tapping in two bilateral upper-extremities amputees with extraordinary foot movement skill.

Functional reorganization of the human brain after an arm amputation has been documented in several investigations, but as far as we know, there has been no report on amputees with skilled foot movement ability. To further assess the power of functional reorganization of the brain after an amputation, we investigated two bilateral upper-extremities amputees who were professional sculptors and painters with their feet. Performance tests showed that they possessed high foot movement ability. Functional MRI data indicated that toe tapping of the amputees not only activated the classical foot primary motor cortex, but also activated the hand area. In the T1-weighted MRI, the central sulci of both amputees kept their characteristic shape. Our study suggests that there is a remarkable power of neural plasticity in the motor cortex, and the maturation of the cortex develops in response to daily practice. The possible mechanisms of the reorganization are tentatively discussed.

Functional magnetic resonance imaging study of writer's cramp.

BACKGROUND: Writer's cramp is a type of task specific idiopathic focal dystonia and has an incompletely understood pathophysiology. The present study utilized functional magnetic resonance imaging (fMRI) to investigate what type of brain activity correlates with writer's cramp and its physiological mechanism. METHODS: Ten patients with writer's cramp were age and gender matched with ten healthy control subjects in a block design. Subjects were scanned by fMRI while performing three consecutive, visually instructive, tasks with MR Vision 2000: (1) suppositional writing, (2) writing with finger and (3) writing with a pencil. Data was analysed using AFNI software for groups of patients and controls. RESULTS: The patients with writer's cramp showed significant activations of contralateral basal ganglion (especially the putamen), motor cortex (primary sensorimotor cortex, supplementary motor cortex, premotor cortex) and ipsilateral cerebellar hemisphere in writing with a pencil compared with controls; whereas there was no obvious difference between patients and controls during writing with finger. Furthermore, these differences exist in the subtractive activated maps for "writing with a pencil" minus "writing with finger" of patients, when the activation of subcortical area and insula in controls disappeared. CONCLUSIONS: Abnormal activations of contralateral basal ganglion, motor cortex and ipsilateral cerebellar hemisphere of the patients with writer's cramp suggest dysfunction of basal ganglion and subcortical-cortical loop might play a pathophysiological role in writer's cramp.

Solid-pseudopapillary tumor of the pancreas: CT and MRI features of 3 cases.

BACKGROUND: Solid-pseudopapillary tumor of the pancreas is a rather rare but low-grade malignant tumor with good prognosis after surgical excision. METHODS: In 3 patients with solid-pseudopapillary tumor of the pancreas which were proved pathologically, the imaging features (CT in all and MRI in one patient) of the tumor were analyzed. RESULTS: In the 3 female patients under 35-year-old who presented no jaundice, CT revealed that huge solid-cystic masses of the pancreatic head with calcification in one and slight dilation of the pancreatic duct in another, but without dilation of the bile duct system in all. MRI demonstrated mixed signal intensity on T1WI and T2WI of the mass in one patient. CT and MRI revealed obvious enhancement of the cystic wall and solid part of the masses. CONCLUSIONS: CT and MRI findings of solid-pseudopapillary tumor of the pancreas are characteristic, and the diagnosis can be made preoperatively with the combination of clinical features.