Generation of Brain Dual-Energy CT from Single-Energy CT Using Deep Learning.

Deep learning (DL) has shown great potential in conversions between various imaging modalities. Similarly, DL can be applied to synthesize a high-kV computed tomography (CT) image from its corresponding low-kV CT image. This indicates the feasibility of obtaining dual-energy CT (DECT) images without purchasing a DECT scanner. In this study, we investigated whether a low-to-high kV mapping was better than a high-to-low kV mapping. We used a U-Net model to perform conversions between different kV CT images. Moreover, we proposed a double U-Net model to improve the quality of original single-energy CT images. Ninety-eight patients who underwent brain DECT scans were used to train, validate, and test the proposed DL-based model. The results showed that the low-to-high kV conversion was better than the high-to-low kV conversion. In addition, the DL-based DECT images had better signal-to-noise ratios (SNRs) than the true (original) DECT images, but at the expense of a slight loss in spatial resolution. The mean CT number differences between the true and DL-based DECT images were within [Formula: see text] 1 HU. No statistically significant difference in CT number measurements was found between the true and DL-based DECT images (p > 0.05). The DL-based DECT images with improved SNR could produce low-noise virtual monoenergetic images. Our preliminary results indicate that DL has the potential to generate brain DECT images using single-energy brain CT images.

The prediction of acute ischemic stroke patients' long-term functional outcomes treated with bridging therapy.

BACKGROUND: Intravenous thrombolysis therapy (IVT) bridged with intra-arterial thrombectomy (IAT) has recently been recommended as favorable treatment option to ensure that the thrombolytic effect is delivered to the affected region for acute ischemic stroke patients. However, there remains a lack of studies reporting outcome prediction in this group of patients. In this study, we aimed to identify indicators from baseline data that could be used for early prediction of long-term functional outcomes. METHODS: This retrospective single center cohort study included acute ischemic stroke (AIS) patients (n = 92) who received IVT and IAT. Functional outcomes were assessed by the National Institute of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS) and Barthel Index. We investigated the relationship between functional outcomes at one-year post-procedure and potential predictors such as occlusion site, modified thrombolysis in cerebral infarction (mTICI) score following the IVT/IAT procedure, and degree of stenosis measured by carotid duplex. RESULTS: 67.4% of the studied patients had satisfactory outcomes with mTICI grades of 2b or 3. From baseline to one-year post-procedure, the NIHSS score improved in 88.0%, the mRS score improved in 69.6%, and the Barthel index improved with 59.8%. Patients with internal carotid artery (ICA) or vertebral artery (VA) stenosis detected by carotid duplex had significantly poorer functional outcomes, measured by the mRS score and Barthel index. In patients with a satisfactory mTICI grade, improvement in the mRS score was only observed in 60.0% of patients with ICA stenosis, compared to 93.8% without ICA stenosis. The VA stenosis was the most significant factor associated with the improvement of mRS (OR = 0.08; 95% CI: 0.01-0.63; P = 0.017) and Barthel Index (OR = 0.06; 95% CI: 0.01-0.47; P = 0.008) in multiple regression analysis. CONCLUSIONS: ICA or VA stenosis detected by carotid duplex could serve as predictors of significantly poorer functional outcomes in stroke patients treated with bridging therapy; they might be useful clinical markers, particularly as stenosis could be detected by a non-invasive and portable method.

Noise reduction in dual-energy computed tomography virtual monoenergetic imaging.

PURPOSE: Virtual monoenergetic images (VMIs) derived from dual-energy computed tomography (DECT) have been explored for several clinical applications in recent years. However, VMIs at low and high keVs have high levels of noise. The aim of this study was to reduce image noise in VMIs by using a two-step noise reduction technique. METHODS: VMI was first denoised using a modified highly constrained backprojection (HYPR) method. After the first-step denoising, a general-threshold filtering method was performed. Two sets of anthropomorphic phantoms were scanned with a clinical dual-source DECT system. DECT data (80/140Sn kV) were reconstructed as VMI series at 12 different energy levels (range, 40-150 keV, interval, 10 keV). For comparison, the averaged VMIs obtained from 10 repeated DECT scans were used as the reference standard. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and root-mean-square error (RMSE) were used to evaluate the quality of VMIs. RESULTS: Compared to the original HYPR method, the proposed two-step image denoising method could provide better performance in terms of SNR, CNR, and RMSE. In addition, the proposed method could achieve effective noise reduction while preserving edges and small structures, especially for low-keV VMIs. CONCLUSION: The proposed two-step image denoising method is a feasible method for reducing noise in VMIs obtained from a clinical DECT scanner. The proposed method can also reduce edge blurring and the loss of intensity in small lesions.

Material decomposition using dual-energy CT with unsupervised learning.

Material decomposition (MD) is an application of dual-energy computed tomography (DECT) that decomposes DECT images into specific material images. However, the direct inversion method used in MD often amplifies noise in the decomposed material images, resulting in lower image quality. To address this issue, we propose an image-domain MD method based on the concept of deep image prior (DIP). DIP is an unsupervised learning method that can perform different tasks without using a large training dataset with known targets (i.e., basis material images). We retrospectively recruited patients who underwent non-contrast brain DECT scans and investigated the feasibility of using the proposed DIP-based method to decompose DECT images into two (i.e., bone and soft tissue) and three (i.e., bone, soft tissue, and fat) basis materials. We evaluated the decomposed material images in terms of signal-to-noise ratio (SNR) and modulation transfer function (MTF). The proposed DIP-based method showed greater improvement in SNR in the decomposed soft-tissue images compared to the direct inversion method and the iterative method. Moreover, the proposed method produced similar MTF curves in both two- and three-material decompositions. Additionally, the proposed DIP-based method demonstrated better separation ability than the other two studied methods in the case of three-material decomposition. Our results suggest that the proposed DIP-based method is capable of unsupervisedly generating high-quality basis material images from DECT images.

Ophthalmic artery flow direction change predicts recurrence of ischemic stroke after carotid stenting: a longitudinal observational study.

BACKGROUND AND PURPOSE: The implantation of carotid artery stents prevents recurrent ischemic stroke in patients with carotid stenosis. This study aimed to investigate associations between change of ophthalmic artery flow (COAF) post carotid stenting and recurrent ischemic stroke, as well as the link toward the anterior and posterior circulations and patients' prognosis after carotid stenting. METHODS: This retrospective, longitudinal cohort study recruited 87 left side carotid stenosed ischemic stroke patients undergoing left side carotid stenting between year of 2009 and 2013, and patients were followed up to 9 years after carotid procedures. Clinical data were derived from medical records. The primary outcome was stroke recurrence. Predictive factors were stenosis > 50% in one intracranial artery and ROAF. Kaplan-Meier and Cox regression analyses were used to identify risk factors associated with stroke recurrence. RESULTS: Among 87 included patients undergone left side carotid stent treatment, 44 had stroke recurrence within 3 years after carotid stenting. The recurrence group had significantly greater proportions of COAF after stenting (p = 0.001), and middle cerebral artery (MCA) and basilar artery or vertebral artery (BA/VA) stenosis > 50% (all p < 0.001) than the no-recurrence group. Survival was significantly shorter in patients with COAF than in those without (p < 0.01). Regression analysis showed that COAF was associated with stroke recurrence (HR: 3.638, 95% CI 1.54-8.62, p = 0.003). The recurrence rate was highest in patients with bilateral MCA stenosis > 50% (100%), followed by left MCA stenosis > 50% plus BA/VA stenosis > 50% (83.33%) or COAF (82.14%). Patients with bilateral MCA stenosis < 50% had no recurrence within 3-year follow-up. CONCLUSIONS: Prognosis after carotid stenting is poorer for patients with MCA stenosis > 50%, BA/VA stenosis > 50% and/or COAF. Carotid duplex and magnetic resonance angiography provide definitive information for prognosis prediction.

Impact of cerebral collateral flow on stroke outcomes after carotid stenting.

OBJECTIVE: Internal carotid artery stenosis is a main contributor to recurrent ischemic stroke. This study aimed to evaluate associations between recurrent stroke and changes in prestenting flow direction in the primary collaterals or both primary and secondary collaterals, and the potential interaction between extra- and intracranial arteries. METHODS: This longitudinal study recruited stroke patients without intracranial stenosis who underwent right-side carotid stenting between 2011 and 2019. The main study outcome was recurrent stroke. Predictive factors were anterior circulation flow direction change (ACFDC), posterior circulation flow direction change, and reversal of ophthalmic artery/leptomeningeal anastomosis (ROALA) detected by transcranial color-coded duplex (TCCD) before carotid stenting. Patient follow-up was 9 years. Risk factors for recurrent stroke were identified by Kaplan-Meier plot and Cox regression analyses. RESULTS: A total of 234 patients (mean age 70.88 ± 10.3 years, 86.32% male) were included, and 115 had recurrent stroke. Kaplan-Meier plot showed that patients with left ACFDC and ROALA had worse outcomes than those with ACFDC only, while patients with left ACFDC had worse outcome than those with right ACFDC (both p < 0.001). Cox regression analysis showed that recurrent stoke was associated with ACFDC at right (hazard ratio [95% CI]: 20.988 [2.549-172.790], p < 0.01), left (151.441 [20.100-1140.993], p < 0.001), and both sides (144.889 [19.089-1099.710], p < 0.001). INTERPRETATION: Anterior circulation flow direction change is significantly associated with recurrent stroke in patients with unilateral carotid stenosis. Patients with ACFDC and ROALA together have worse outcomes compared to those with ACFDC only. Prestenting TCCD images help provide definitive information to predict outcomes after carotid stenting.

The age factor influencing long-term physical functionality in stroke patients undergoing intra-arterial thrombectomy treatment.

The treatment of acute ischemic stroke is heavily time-dependent, and even though, with the most efficient treatment, the long-term functional outcome is still highly variable. In this current study, the authors selected acute ischemic stroke patients who were qualified for intravenous thrombolysis with recombinant tissue plasminogen activator and followed by intra-arterial thrombectomy. With primary outcome defined by the functional level in a 1-year follow-up, we hypothesize that patients with older age are at a disadvantage in post-stroke recovery. However, an age-threshold should be determined to help clinicians in selection of patients to undergo such therapy. This is a retrospective chart review study that include 92 stroke patients in Changhua Christian hospital with a total of 68 evaluation indexes recorded. The current study utilized the forward stepwise regression model whose Adj-R2 and P value in search of important variables for outcome prediction. The chngpt package in R indicated the threshold point of the age factor directing the better future functionality of the stroke patients. Datasets revealed the threshold of the age set at 79 the most appropriate. Admission Barthel Index, Age, ipsilateral internal carotid artery resistance index (ICA RI), ipsilateral vertebral artery (VA) PI, contralateral middle cerebral artery (MCA) stenosis, contralateral external carotid artery (ECA) RI, and in-hospital pneumonia are the significant predicting variables. The higher the age, in-hospital pneumonia, contralateral MCA stenosis, ipsilateral ICA RI and ipsilateral VA PI, the less likely patient to recover from functional deficits as the result of acute ischemic stroke; the higher the value of contralateral ECA RI and admission Barthel Index, the better chance to full functional recovery at 1-year follow up. Parameters of pre-intervention datasets could provide important information to aid first-line clinicians in decision making. Especially, in patients whose age is above 79 receives diminish return in the benefit to undergo such intervention and should be considered seriously by both the patients and the physicians.

Predictive Factors of Cerebral Aneurysm Rerupture After Clipping.

BACKGROUND: We aimed to estimate the risk of rerupture after first-time aneurysmal clipping surgery, explore the possible related factors, and assess long-term physical functionality. We hypothesized that the modified Rankin scale (mRS) could serve as an effective substitute for Hunter and Hess scale. METHODS: This retrospective study included 171 patients with cerebral aneurysmal rupture who had completed aneurysmal clipping treatment and collected their demographic data and medical records. The outcome assessments include neuroimaging records, Hunter and Hess scale, and the mRS scale during hospitalization and follow-up after discharge. The mean length of follow-up was 4.28 years. RESULTS: After aneurysmal clipping treatment, 83 patients (48.5%) had subsequently ruptured aneurysms. The scores of the reruptured group on the Hunt and Hess scale and mRS were significantly higher than those of the non-reruptured group. Multiple Cox proportional-hazards regression also showed that postoperative mRS >2, smoking, and two or more aneurysms were potentially important risk factors leading to aneurysm rupture again [the corresponding hazard ratios (HRs) were 5.209, 2.109, and 2.775, respectively] in patients. In addition, the location of an aneurysm on the anterior cerebral artery (ACA) or the posterior communicating (Pcom) artery had a higher risk of rerupture (the corresponding HRs were 1.996 and 2.934, respectively). CONCLUSIONS: Nearly half of the collected participants experienced the rerupture episode, who had undergone the second-time clipping surgery. Smoking and multiple aneurysms are potential risk factors for aneurysmal rerupture. Most aneurysms are located along the ICA, but aneurysms located at the ACA or Pcom site are most likely to rerupture. As compared with the Hunter and Hess scale, the mRS scale does not have inferior predicting power in following patients' long-term functionalities.

Carotid duplex parameters to predict long term outcomes of ischemic stroke patients receiving intra-arterial thrombectomy treatment.

Early treatment of acute ischemic stroke with intravenous thrombolysis therapy (ITT) followed by intra-arterial thrombectomy (IAT) is a promising new treatment option for improving functional outcomes. Identifying patients who will benefit from this treatment combination is important.A total of 92 acute ischemic stroke patients who received ITT and IAT with a minimum of 1-year follow-up were included in the study. All parameters of clinical and imaging examinations at baseline were examined which parameters were significantly correlated with the 1-year functional outcomes (modified Rankin scale [mRS], National Institute of Health Stroke Scale [NIHSS], and Barthel Index) after stroke. Receiver-operating characteristic (ROC) curves analysis was performed to estimate the diagnostic performance of each significantly related parameter. Youden index was used to determine the optimal threshold value. Multivariate logistic regression model analyses were applied to verify the results of predicting the favorable functional outcomes.Immediate postoperation outcome with modified thrombolysis in cerebral infarction grading showed that total of 62 patients qualified for satisfactory result (2b or 3). In predicting NIHSS improvement, ROC curve analysis showed that a cutoff point of vertebral artery pulsatility index (VA PI)-ipsilateral ≤2.3 yields the best diagnostic performance (area under the ROC curve [AUC] = 0.728); in predicting mRS improvement, VA PI-ipsilateral ≤1.92 and internal carotid artery resistance index (ICA RI)-ipsilateral ≤0.71 yield good diagnostic performance (AUC = 0.697 and 0.672, respectively); and ICA RI-contralateral ≤0.70 or plaque index-ipsilateral ≤2 had better diagnostic accuracy (AUC = 0.764 and 0.689, respectively) than other indices to predict Barthel index improvement. The multivariate analysis also showed that these 5 indices were those more powerful and highly significant favorable functional outcomes predictors.Parameters of pulsatility and resistance index from carotid duplex could be easily accessed and noninvasive. The outcome of ischemic stroke patients receiving ITT followed by IAT can be forecasted by these 2 crucial predictors that hint the patients' functional outcomes as well as guiding first line in-charge clinician in terms of decision making.

Reversed ophthalmic artery flow following ischemic stroke: a possible predictor of outcomes following carotid artery stenting.

Stroke is the leading cause of death worldwide and stenosis of the carotid artery accounts for more than half of all cases. Carotid duplex is an effective non-invasive ultrasound test which identifies stroke patients with moderate to severe carotid stenosis who are candidates for preventative intervention to reduce the risk of recurrence. In patients with moderate to severe carotid stenosis, reversed ophthalmic artery flow (ROAF) is often observed at the time of the carotid duplex scan. In this study, we investigated whether ROAF, denoting exhaustion of cerebral collateral flow in ischemic stroke patients affected mid-term functional outcomes following carotid artery stenting (CAS) procedures. In total, 144 consecutive patients with a first episode of ischemic stroke and subsequent CAS procedure conducted between January 2010 and November 2014 at Changhua Christian Hospital, Taiwan were included. Clinical data were obtained by medical record review. Disability was assessed at two time points by utilising the Barthel Index (BI) and modified Rankin Scale (mRS) before CAS and 12 months post-CAS. Among 85 patients presenting without ROAF, 48/85 (56.4%) had improved mRS scores following stenting. The condition remained unchanged (stationary) in 36/85 (43.5%) patients after stenting and one patient exhibited deteriorated condition 1/85(1.1%). In contrast, among the 59 patients presenting with ROAF, 24/59 (40.6%) had improved mRS score following stenting. The condition remained unchanged (stationary) in the remaining 35/59 (59.3%) patients after stenting, and no patient exhibited deteriorated condition 0/59 (0 %). This study provides evidence that CAS is a valid and effective treatment option regardless of whether patients exhibited ROAF or not. Patients without ROAF were significantly more likely to have improved mid-term functional outcomes compared to those with ROAF. In the group without ROAF admission, CRP may play a role in predicting subsequent functional outcomes, whereas admission Barthel Index was a predictor of outcome in the ROAF group.

Is carotid sonography a useful tool for predicting functional capabilities in ischemic stroke patients following carotid artery stenting?

Carotid stenosis is a major cause of stroke and timely intervention with stenting manipulation can significantly reduce the risk of secondary stroke. The impact of stenting procedures on patient functional capabilities has not yet been explored. The primary aim of this study was to examine associations between periprocedural carotid sonography parameters and post-treatment functional capabilities in stroke patients.Sixty-seven patients who received carotid stenting at 1 angiography laboratory were included. Prestenting and poststenting carotid duplex data were recorded and resistance index (RI) differences at various carotid system locations were compared. The modified Rankin Scale (mRS) was used to assess functional capability. All of the studied parameters were analyzed by SPSS (version 16.0, SPSS Inc, Chicago, IL).Following stenting, mRS scores improved (n = 44) or remained stationary (n = 23). Net contralateral internal carotid artery (ICA) RI for patients with improved mRS was lower compared to that for patients with stationary mRS (median = 0.040 vs 0.11; P = 0.003). The contralateral common carotid artery RI before and after stenting differed significantly (P < 0.050) in both. The ipsilateral ICA RI differed (P < 0.050) only in patients with improved mRS. The difference in mean transit time, Barthel index, net ipsilateral ICA RI, net contralateral external carotid artery RI, postipsilateral common carotid artery RI, and postipsilateral ICA RI differed significantly between different baseline stroke severity groups (P < 0.050).Carotid artery stenting improved physical function in a proportion of ischemic stroke patients with carotid stenosis. Carotid ultrasound is a useful assessment tool to predict likely functional outcomes following carotid artery stenting.

Impact of baseline characteristics on outcomes of carotid artery stenting in acute ischemic stroke patients.

Carotid artery stenting is an effective treatment for ischemic stroke patients with moderate-to-severe carotid artery stenosis. However, the midterm outcome for patients undergoing this procedure varies considerably with baseline characteristics. To determine the impact of baseline characteristics on outcomes following carotid artery stenting, data from 107 eligible patients with a first episode of ischemic stroke were collected by retrospective chart review. A modified Rankin Scale (mRS) was used to divide patients into two baseline groups, mRS ≤2 and mRS >2. A three-step decision-tree statistical analysis was conducted. After weighting the decision-tree parameters, the following impact hierarchy was obtained: admission low-density lipoprotein, gouty arthritis, chronic kidney disease, ipsilateral common carotid artery resistance index, contralateral ophthalmic artery resistance index, sex, and dyslipidemia. The finite-state machine model demonstrated that, in patients with baseline mRS ≤2, 46% had an improved mRS score at follow-up, whereas 54% had a stable mRS score. In patients with baseline mRS >2, a stable mRS score was observed in 75%, improved score in 23%, and a poorer score in 2%. Admission low-density lipoprotein was the strongest predictive factor influencing poststenting outcome. In addition, our study provides further evidence that carotid artery stenting can be of benefit in first-time ischemic stroke patients with baseline mRS scores >2.

Role of Extracranial Carotid Duplex and Computed Tomography Perfusion Scanning in Evaluating Perfusion Status of Pericarotid Stenting.

Carotid stenting is an effective treatment of choice in terms of treating ischemic stroke patients with concomitant carotid stenosis. Though computed tomography perfusion scan has been recognized as a standard tool to monitor/follow up this group of patients, not everyone could endure due to underlying medical illness. In contrast, carotid duplex is a noninvasive assessment tool and could track patient clinical condition in real time. In this study we found that "resistance index" of the carotid ultrasound could detect flow changes before and after the stenting procedure, thus having great capacity to replace the role of computed tomography perfusion exam.

First-ever ischemic stroke in elderly patients: predictors of functional outcome following carotid artery stenting.

Age is an important risk factor for stroke, and carotid artery stenosis is the primary cause of first-ever ischemic stroke. Timely intervention with stenting procedures can effectively prevent secondary stroke; however, the impact of stenting on various periprocedural physical functionalities has never been thoroughly investigated. The primary aim of this study was to investigate whether prestenting characteristics were associated with long-term functional outcomes in patients presenting with first-ever ischemic stroke. The secondary aim was to investigate whether patient age was an important factor in outcomes following stenting, measured by the modified Rankin scale (mRS). In total, 144 consecutive patients with first-ever ischemic stroke who underwent carotid artery stenting from January 2010 to November 2014 were included. Clinical data were obtained by review of medical records. The Barthel index (BI) and mRS were used to assess disability before stenting and at 12-month follow-up. In total, 72/144 patients showed improvement (mRS[+]), 71 showed stationary and one showed deterioration in condition (mRS[-]). The prestenting parameters, ratio of cerebral blood volume (1.41 vs 1.2 for mRS[-] vs mRS[+]), BI (75 vs 85), and high-sensitivity C-reactive protein (hsCRP 5.0 vs 3.99), differed significantly between the two outcome groups (P<0.05). The internal carotid artery/common carotid artery ratio (P=0.011), BI (P=0.019), ipsilateral internal carotid artery resistance index (P=0.003), and HbA1c (P=0.039) were all factors significantly associated with patient age group. There was no significant association between age and poststenting outcome measured by mRS with 57% of patients in the ≥75 years age group showing mRS(-) and 43% showing mRS(+) (P=0.371). Our findings indicate that in our elderly patient series, carotid artery stenting may benefit a significant proportion of carotid stenotic patients regardless of age. Ratio of cerebral blood volume, BI, and admission hsCRP could serve as important predictors of mRS improvement and may facilitate differentiation of patients at baseline.

Is unenhanced 18F-FDG-PET/CT better than enhanced CT in the detection of retropharyngeal lymph node metastasis in nasopharyngeal carcinoma?

Positron-emission tomography/computed tomography (PET/CT) has been proposed as a means to enhance the pretreatment evaluation of cervical lymph node status in patients with nasopharyngeal carcinoma (NPC). We conducted a prospective study to compare PET/CT and enhanced CT for the detection of retropharyngeal lymph node (RLN) metastasis in NPC, and to ascertain the factors that affect its diagnostic performance. Our study population was made up of 33 patients-24 men and 9 women, aged 30 to 81 years (mean: 52)-with newly diagnosed NPC who had been treated over a 2-year period. All patients underwent enhanced CT first, followed by unenhanced 18F-fluorodeoxyglucose (FDG) PET/CT. The detection rate of RLN metastasis on PET/CT was significantly lower than that on enhanced CT (36.4 vs. 75.8%; p < 0.001). A total of 25 of 26 nodes with a discordant finding were negative on PET/CT; they included 13 metastatic lymph nodes with low FDG uptake, 9 that were located close to the primary tumor, 2 that were confluent RLNs, and 1 that was adjacent to the physiologic FDG-avid prevertebral muscle. The maximum standardized uptake value (SUVmax) of RLNs was positively correlated with the minimum axial diameter (r = 0.803, p < 0.001). The PET/CT detection rate was 0% for lymph nodes smaller than 5 mm, 9% for those 5 to 10 mm, and 73% for those 1 cm or larger. The detection rate of PET/CT at level C1 was significantly lower than that at C2 (22 vs. 67%; p = 0.035). We conclude that unenhanced PET/CT is markedly inferior to enhanced CT for detecting RLN metastasis in NPC, especially in lymph nodes with a minimum axial diameter of less than 1 cm and those in proximity to the primary tumor. Using enhanced CT in PET/CT is justified to improve the recognition of RLN metastasis in patients with NPC.

Fuzzy C-means clustering of magnetic resonance imaging on apparent diffusion coefficient maps for predicting nodal metastasis in head and neck cancer.

OBJECTIVE: The present study evaluated and analyzed apparent diffusion coefficients (ADCs) from partitions through a fuzzy C-means (FCM) technique for distinguishing nodal metastasis in head and neck cancer. METHODS: MRI studies of 169 lymph node lesions, dissected from 22 patients with a histopathologically confirmed lymph node status, were analyzed using in-house software developed using MATLAB(®) (The MathWorks(®) Inc., Natick, MA). A radiologist manually contoured the lesions, and ADCs for each lesion were divided into two (low and high) and three (low, intermediate and high) partitions by using the FCM clustering algorithm. RESULTS: The results showed that the low-value ADC clusters were more sensitive (95.7%) in distinguishing malignant from benign lesions than the whole-lesion mean ADC values (78.3%), while retaining a high specificity (approximately 90%). Moreover, receiver-operating characteristic curves demonstrated that the low-value ADC clusters used as a predictor of malignancy for lymph nodes could achieve a higher area under the curve (0.949 and 0.944 for two and three partitions, respectively). CONCLUSION: The segmentation by ADC values of lesions through the FCM technique enables the efficient characterization of the lymph node pathology and can help distinguish malignant from benign lymph nodes. ADVANCES IN KNOWLEDGE: Tumour heterogeneity may degrade the prediction of metastatic lymph nodes that involves using mean region-of-interest ADC values. The clustering of ADC values in lesions by using FCM can improve the diagnostic accuracy of nodal metastasis and reduce interreader variance.

Reversible cerebral periventricular white matter changes with corpus callosum involvement in acute toluene-poisoning.

Substance poisoning, such as toluene intoxication, has seldom been reported in the relevant literature. The documented cerebral neuroimaging has mostly described reversible symmetrical white matter changes in both the cerebral and cerebellar hemispheres. This paper presents 2 patients with toluene poisoning, whose brain magnetic resonance imaging studies showed a similar picture that included extra involvement over the corpus callosum; however, such corpus callosum involvement has never been mentioned and is quite rare in the literature. We discussed the underlying neuropathological pathways in this article. Hopefully, these cases will provide first-line clinicians with some valuable information with regard to toluene intoxication and clinical neuroimaging presentations.

Bilateral hemiballism-hemi-chorea presenting in a diabetes taiwanese woman.

Hemiballism-hemichorea (HB-HC) is a hyperkinetic disorder characterized by continuous involuntary movements of the extremities. It could be associated with non-insulin dependent diabetes mellitus. A very few cases of bilateral HB-HC have been reported until today. We describe here the case of a Taiwanese woman (85 years old) presenting with bilateral HB-HC and diabetes mellitus.

Intracranial venous hemodynamics and rupture of cerebral aneurysm.

Many uncertain and inconsistent etiologies of cerebral aneurysmal rupture including a wide spectrum of factors have been reported. Our recent observation discloses the potential new factor of cerebral aneurysm rupture with cerebral venous pressure gradient. We retrospectively reviewed 52 cases treated with coil embolization with or without cerebral aneurysmal rupture. Seventeen males and 30 females were recruited in this study. Quantitative color-coded cerebral angiography was performed during coil therapeutic procedures to measure cerebral venous circulation. Ruptured cases had shorter and symmetrical cerebral venous circulation time (P <0.05). In addition, an asymmetrical venous outflow pattern was critical for aneurysmal rupture. Non-ruptured cases tended to have slower and asymmetrical cerebral venous circulation compared with rupture cases. Symmetrical and shorter cerebral venous circulation in the dysplasia venous outlet may be a potential new factor for cerebral aneurysm rupture.

Clinical impact of multidetector computed tomography before double-balloon enteroscopy for obscure gastrointestinal bleeding.

AIM: To evaluate the clinical impact of multidetector computed tomography (MDCT) before double-balloon endoscopy (DBE) for patients with obscure gastrointestinal bleeding (OGIB). METHODS: A retrospective analysis of prospectively collected cases with DBE and MDCT for overt OGIB was conducted from April 2004 to April 2010 at Changhua Christian Hospital. We evaluated the clinical impact of MDCT on the subsequent DBE examinations and the diagnostic yields of both MDCT and DBE respectively. RESULTS: From April 2004 to April 2010, a total of 75 patients underwent DBE for overt OGIB. Thirty one cases received MDCT followed by DBE for OGIB. The overall diagnostic yields of DBE and MDCT was 93.5% and 45.2%. The MDCT had a high diagnostic yield of tumor vs non-tumor etiology of OGIB (85.7% vs 33.3%, P = 0.014). Additionally, the choice of initial route of DBE was correct in those with a positive MDCT vs negative MDCT (100% vs 52.9%, P = 0.003). CONCLUSION: This study suggests MDCT as a triage tool may identify patients who will benefit from DBE and aid the endoscopist in choosing the most efficient route.