Neurovascular coupling in eye-open-eye-close task and resting state: Spectral correspondence between concurrent EEG and fMRI.

Neurovascular coupling serves as an essential neurophysiological mechanism in functional neuroimaging, which is generally presumed to be robust and invariant across different physiological states, encompassing both task engagement and resting state. Nevertheless, emerging evidence suggests that neurovascular coupling may exhibit state dependency, even in normal human participants. To investigate this premise, we analyzed the cross-frequency spectral correspondence between concurrently recorded electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data, utilizing them as proxies for neurovascular coupling during the two conditions: an eye-open-eye-close (EOEC) task and a resting state. We hypothesized that given the state dependency of neurovascular coupling, EEG-fMRI spectral correspondences would change between the two conditions in the visual system. During the EOEC task, we observed a negative phase-amplitude-coupling (PAC) between EEG alpha-band and fMRI visual activity. Conversely, in the resting state, a pronounced amplitude-amplitude-coupling (AAC) emerged between EEG and fMRI signals, as evidenced by the spectral correspondence between the EEG gamma-band of the midline occipital channel (Oz) and the high-frequency fMRI signals (0.15-0.25 Hz) in the visual network. This study reveals distinct scenarios of EEG-fMRI spectral correspondence in healthy participants, corroborating the state-dependent nature of neurovascular coupling.

White matter alterations and their associations with biomarkers and behavior in subjective cognitive decline individuals: a fixel-based analysis.

BACKGROUND: Subjective cognitive decline (SCD) is an early stage of dementia linked to Alzheimer's disease pathology. White matter changes were found in SCD using diffusion tensor imaging, but there are known limitations in voxel-wise tensor-based methods. Fixel-based analysis (FBA) can help understand changes in white matter fibers and how they relate to neurodegenerative proteins and multidomain behavior data in individuals with SCD. METHODS: Healthy adults with normal cognition were recruited in the Northeastern Taiwan Community Medicine Research Cohort in 2018-2022 and divided into SCD and normal control (NC). Participants underwent evaluations to assess cognitive abilities, mental states, physical activity levels, and susceptibility to fatigue. Neurodegenerative proteins were measured using an immunomagnetic reduction technique. Multi-shell diffusion MRI data were collected and analyzed using whole-brain FBA, comparing results between groups and correlating them with multidomain assessments. RESULTS: The final enrollment included 33 SCD and 46 NC participants, with no significant differences in age, sex, or education between the groups. SCD had a greater fiber-bundle cross-section than NC (pFWE < 0.05) at bilateral frontal superior longitudinal fasciculus II (SLFII). These white matter changes correlate negatively with plasma Aß42 level (r = -0.38, p = 0.01) and positively with the AD8 score for subjective cognitive complaints (r = 0.42, p = 0.004) and the Hamilton Anxiety Rating Scale score for the degree of anxiety (Ham-A, r = 0.35, p = 0.019). The dimensional analysis of FBA metrics and blood biomarkers found positive correlations of plasma neurofilament light chain with fiber density at the splenium of corpus callosum (pFWE < 0.05) and with fiber-bundle cross-section at the right thalamus (pFWE < 0.05). Further examination of how SCD grouping interacts between the correlations of FBA metrics and multidomain assessments showed interactions between the fiber density at the corpus callosum with letter-number sequencing cognitive score (pFWE < 0.01) and with fatigue to leisure activities (pFWE < 0.05). CONCLUSION: Based on FBA, our investigation suggests white matter structural alterations in SCD. The enlargement of SLFII's fiber cross-section is linked to plasma Aß42 and neuropsychiatric symptoms, which suggests potential early axonal dystrophy associated with Alzheimer's pathology in SCD. The splenium of the corpus callosum is also a critical region of axonal degeneration and cognitive alteration for SCD.

The two-back task leads to activity in the left dorsolateral prefrontal cortex in schizophrenia patients with predominant negative symptoms: a fNIRS study and its implication for tDCS.

Transcranial direct current stimulation (tDCS) over left dorsolateral prefrontal cortex (DLPFC) has shown some potential as an adjunctive intervention for ameliorating negative symptoms of schizophrenia, but its efficacy requires optimization. Recently, 'functional targeting' of stimulation holds promise for advancing tDCS efficacy by coupling tDCS with a cognitive task where the target brain regions are activated by that task and further specifically polarized by tDCS.The study used 48-channel functional near infra-red spectroscopy (fNIRS) aiming to determine a cognitive task that can effectively induce a cortical activation of the left DLPFC in schizophrenia patients with predominant negative symptoms before running a tDCS trial. Sixty schizophrenia patients with predominant negative symptoms completed measures of clinical and psychosocial functioning characteristics and assessments across cognitive domains. Hemodynamic changes during n-back working memory tasks with different cognitive loads (1-back and 2-back) and verbal fluency test (VFT) were measured using fNIRS. For n-back tasks, greater signal changes were found when the task required elevated cognitive load. One sample t-test revealed that only 2-back task elicited significant activation in left DLPFC (t = 4.23, FDR-corrected p = 0.0007). During VFT, patients failed to show significant task-related activity in left DLPFC (one sample t-test, t = -0.25, FDR-corrected p > 0.05). Our study implies that 2-back task can effectively activate left DLPFC in schizophrenia patients with predominant negative symptoms. This neurophysiologically-validated task is considered highly potential to be executed in conjunction with high-definition tDCS for "functional targeting" of the left DLPFC to treat negative symptoms in a double-blind randomized sham-control trial, registered on ClinicalTrials.gov Registry (ID: NCT05582980).

Value of CT in targeted CT-guided epidural blood patching: Predictors for successful epidural punctures.

BACKGROUND AND PURPOSE: Differentiating epidural from intrathecal punctures before computed tomography (CT)-guided epidural blood patching (EBP) is subjective, relying on operator experience. This study aimed to investigate CT findings for epidural and intrathecal punctures and identify reliable predictors for successful epidural punctures before targeted CT-guided EBP. MATERIALS AND METHODS: We included 65 patients with low-cerebrospinal fluid (CSF)-pressure headache receiving targeted CT-guided EBP between January 2021 and October 2022 in this retrospective study. We analyzed clinical data, technical information, and CT features before EBP. Fisher's exact test was used for discrete variables, while Mann-Whitney U test was used for continuous variables. Positive (PLR) and negative likelihood ratios (NLR) were calculated to identify predictors for confirming epidural punctures. RESULTS: We confirmed 43 patients as epidural punctures and 22 patients as intrathecal punctures. Before contrast injection, epidural fat at the needle tip in the epidural group was higher than the intrathecal group (37.2 % [16/43] vs. 4.5 % [1/22], p = 0.006). After contrast injection, the "contrast-needle tip connection" sign was mostly observed in the epidural group than the intrathecal group (95.3 % [41/43] vs. 9.1 % [2/22], p < 0.001). Additionally, the epidural group had significantly higher boomerang-shaped contrast morphology than the intrathecal group (65.1 % [28/43] vs. 9.1 % [2/22], p < 0.001). The "contrast-needle tip connection" sign had the highest PLR (10.49) and lowest NLR (0.05). CONCLUSION: Identifying epidural fat at the needle tip, "contrast-needle tip connection" sign, and boomerang-shaped contrast morphology on CT scans are useful for confirming proper placement of the needle tip within the epidural space.

Simultaneous Patent Blue Dye Injections Aid in the Preoperative CT-Guided Localization of Multiple Pulmonary Nodules.

Background and Objectives: Clinically, a major challenge of multiple nodule localization is puncture-related pneumothorax, which may hamper the successful localization. This study aims to investigate and compare the efficacy and safety of the simultaneous and sequential patent blue dye (PBD) injections for identifying multiple pulmonary nodules during preoperative CT-guided localization. Materials and Methods: Sixty-one consecutive patients with multiple pulmonary nodules who underwent preoperative CT-guided localization with PBD injections between January 2020 and December 2020 were retrospectively enrolled. Of these patients, 31 patients with 64 nodules who underwent simultaneous injections were designated as the simultaneous group; the remaining 30 patients with 63 nodules who underwent sequential punctures were designated as the sequential group. The clinical and radiological features, technical information, pathological results, and procedure-related variables and complications of the two groups were reviewed and analyzed. Results: The localization success rate of the simultaneous group was higher than that of the sequential group (100% [64/64] vs. 93.7% [59/63], p = 0.041). The incidences of pneumothorax (32.3 vs. 33.3%, p = 0.929) and pulmonary hemorrhage (6.3 vs. 3.0%, p = 1) were not significantly different between the two groups, and all cases were minor, which did not require further intervention. Additionally, a significantly lower radiation dose (2.7 vs. 3.5 mSv, p = 0.001) and a shorter procedure time (20.95 vs. 25.28 min, p = 0.001) were observed in the simultaneous group than in the sequential group. Conclusions: Compared with the sequential method, simultaneous PBD injections may improve the localization success rate with a shorter procedure time and less radiation exposure if the patient with multiple pulmonary nodules can be approached in a single position. Further prospective studies are needed to validate these results.

Bowel Wall Visualization Using MR Enterography in Relationship to Bowel Lumen Contents and Patient Demographics.

BACKGROUND: MR enterography (MRE) is generally performed without bowel preparation, but the frequency and extent by which bowel contents affect bowel wall visualization are poorly described in the literature. PURPOSE: To evaluate MRE bowel wall visualization quality relative to bowel lumen contents and patient demographics. STUDY TYPE: Retrospective, single-center. POPULATION: One hundred and four consecutive patients (mean age 29 years, range 5-76 years) without prior bowel resection who had undergone MRE. FIELD STRENGTH/SEQUENCE: 3 T (N = 87) or 1.5 T (N = 17)/T2-weighted single-shot spin echo (T2WI) and fat-saturated T1-weighted gradient echo (T1WI) without and with gadolinium. ASSESSMENT: For the proximal and distal jejunum and ileum and colon, three readers independently categorized bowel lumen signal (water = bright T2 dark T1, T1-bright, or air = dark T2 and T1 signal) and scored distension (0 = poor, 1 = moderate, 2 = well) and wall enhancement (0 = unclear, 1 = perceptible, 2 = clear) based upon gadolinium enhanced T1WI for the 104 MRE exams). The bowel visualization score was the sum of the wall enhancement and distension scores and was considered adequate if ≥3. STATISTICAL TESTS: Wilcoxon signed-rank test. RESULTS: The bowel lumen content was water signal in 93% (97/104 scans), 92% (95/104), 98% (102/104), and 93% (92/104) of the proximal and distal jejunum and proximal and distal ileum, respectively, but only in 12.5% (13/104) of the colon. There was adequate bowel visualization of 53.8%, 77.8%, 84.6%, 90.4% of the proximal and distal jejunum and proximal and distal ileum, respectively, but only 19.2% of the colon. In children (age < 18 years), the visualization score of the ileum was lower when the adjacent colon contained air (2.4 ± 0.97) compared to water (3.75 ± 0.29, P < 0.05) or T1-bright material (3.21 ± 0.82, P < 0.05). DATA CONCLUSION: Without bowel preparation, colon wall visualization was often unsatisfactory at MRE, and air-filled colon also degraded small bowel visualization, particularly in children. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 1.

Differentiating focal interstitial fibrosis from adenocarcinoma in persistent pulmonary subsolid nodules (> 5 mm and < 20 mm): the role of coronal thin-section CT images.

OBJECTIVES: To investigate thin-section computed tomography (CT) features of pulmonary subsolid nodules (SSNs) with sizes between 5 and 20 mm to determine predictive factors for differentiating focal interstitial fibrosis (FIF) from adenocarcinoma. METHODS: From January 2017 to December 2018, 169 patients who had persistent SSNs 5-20 mm in size and underwent preoperative nodule localization were enrolled. Patient characteristics and thin-section CT features of the SSNs were reviewed and compared between the FIF and adenocarcinoma groups. Univariable and multivariable analyses were used to identify predictive factors of malignancy. Receiver operating characteristic (ROC) curve analysis was used to quantify the performance of these factors. RESULTS: Among the 169 enrolled SSNs, 103 nodules (60.9%) presented as pure ground-glass opacities (GGOs), and 40 (23.7%) were FIFs. Between the FIF and adenocarcinoma groups, there were significant differences (p< 0.05) in nodule border, shape, thickness, and coronal/axial (C/A) ratio. Multivariable analysis demonstrated that a well-defined border, a nodule thickness >4.2, and a C/A ratio >0.62 were significant independent predictors of malignancy. The performance of a model that incorporated these three predictors in discriminating FIF from adenocarcinoma achieved a high area under the ROC curve (AUC, 0.979) and specificity (97.5%). CONCLUSIONS: For evaluating persistent SSNs 5-20 mm in size, the combination of a well-defined border, a nodule thickness > 4.2, and a C/A ratio > 0.62 is strongly correlated with malignancy. High accuracy and specificity can be achieved by using this predictive model. KEY POINTS: • Thin-section coronal images play an important role in differentiating FIF from adenocarcinoma. • The combination of a well-defined border, nodule thickness>4.2 mm, and C/A ratio >0.62 is associated with malignancy. • This predictive model may be helpful for managing persistent SSNs between 5 and 20 mm in size.

Post-operative assessment in patients after liver transplantation: imaging parameters associated with 1-year graft failure.

PURPOSE: To identify post-liver transplant CT findings which predict graft failure within 1 year. MATERIALS AND METHODS: We evaluated the CT scans of 202 adult liver transplants performed in our institution who underwent CT within 3 months after transplantation. We recorded CT findings of liver perfusion defect (LPD), parenchymal homogeneity, and the diameters and attenuations of the hepatic vessels. Findings were correlated to 1-year graft failure, and interobserver variability was assessed. RESULTS: Forty-one (20.3%) of the 202 liver grafts failed within 1 year. Graft failure was highly associated with LPD (n = 18/25, or 67%, versus 15/98, or 15%, p < 0.001), parenchymal hypoattenuation (n = 20/41, or 48.8% versus 17/161, or 10.6%, p < 0.001), and smaller diameter of portal veins (right portal vein [RPV], 10.7 ± 2.7 mm versus 14.7 ± 2.2 mm, and left portal vein [LPV], 9.8 ± 3.0 mm versus 12.4 ± 2.2 mm, p < 0.001, respectively). Of these findings, LPD (hazard ratio [HR], 5.43, p < 0.001) and small portal vein diameters (HR, RPV, 3.33, p < 0.001, and LPV, 3.13, p < 0.05) independently predicted graft failure. All the measurements showed fair to moderate interobserver agreement (0.233~0.597). CONCLUSION: For patients who have CT scan within the first 3 months of liver transplantation, findings of LPD and small portal vein diameters predict 1-year graft failure. KEY POINTS: •Failed grafts are highly associated with liver perfusion defect, hypoattenuation, and small portal vein. •Right portal vein < 11.5 mm and left portal vein < 10.0 mm were associated with poor graft outcome. •Liver perfusion defect and small portal vein diameter independently predicted graft failure.

Fried egg sign: A typical ultrasonography feature of neurolymphomatosis.

Neurolymphomatosis (NL) is a rare condition caused by non-Hodgkin's lymphoma or leukemia. We present a case of NL and describe ultrasound features, including the "fried egg sign" in which there is a clear demarcation between an avascular echogenic core and a hypoechoic vascularized peripheral zone that may help to distinguish NL from primary nerve sheath tumors.

Appearance and Frequency of Gas Interface Artifacts Involving Small Bowel on Rapid-Voltage-Switching Dual-Energy CT Iodine-Density Images.

OBJECTIVE: The purpose of this study is to describe the appearance and frequency of gas interface artifacts in the jejunum that may mimic severe bowel disease on iodine-density images generated from rapid-voltage-switching dual-energy CT (DECT) scans. MATERIALS AND METHODS: Two readers retrospectively reviewed 108 consecutive abdominal rapid-voltage-switching DECT scans to record the presence of image artifacts in jejunal segments with different degrees of gaseous luminal filling, classified as full, partial, or absent. Readers viewed iodine-density images and corresponding 140-kVp and 65-keV virtual monochromatic images and classified the jejunal artifacts on iodine-density images as pseudostratified appearance of the bowel wall, pseudopneumatosis, pseudohyperenhancement, or pseudohypoenhancement. We correlated the presence of the artifacts with clinical features suggesting bowel disease. RESULTS: Image artifacts were found in 91 of 108 scans (84.3%), appeared in 148 of 265 jejunal segments (55.8%), and included each type except for pseudohypoenhancement. Artifacts occurred exclusively when gas was present in the bowel lumen and were seen in 59 of 59 (100%) fully gas-distended segments, 89 of 98 (90.8%) partially gas-distended segments, and none of 108 gas-absent segments (p < 0.0001). In fully and partially gas-distended jejunal segments (n = 157), 148 (94.3%) segments had two or more artifacts. None of the patients was found to have clinical bowel-related injury on follow-up of medical records. CONCLUSION: Pseudostratified appearance, pseudopneumatosis, and pseudohyperenhancement, but not pseudohypoenhancement, artifacts are common in gas-filled jejunal segments on iodine-density images generated from rapid-voltage-switching DECT scans and are not seen in the corresponding 140-kVp or 65-keV images. Knowledge of the appearance of such iodine-density image artifacts will avoid potential examination interpretation pitfalls.

CT Findings for Detecting the Presence of Gangrenous Ischemia in Cholecystitis.

OBJECTIVE: The objective of our study was to evaluate the diagnostic accuracy of CT in differentiating gangrenous cholecystitis from uncomplicated cholecystitis and healthy gallbladders. MATERIALS AND METHODS: We performed a retrospective review of 308 patients with histologically proven gangrenous cholecystitis who underwent preoperative CT 1 month before gallbladder removal over a 4-year period. Two readers who were blinded to the histologic diagnosis independently recorded CT features of and overall likelihood of gangrenous cholecystitis on a 5-point scale (1, definitely absent; 5, definitely present). Ratings were dichotomized such that a diagnosis was considered present at a rating of 4 or 5 and considered absent at lower ratings. Interobserver variability for individual CT findings was also assessed. RESULTS: Patients had gangrenous cholecystitis (n = 28), acute cholecystitis (n = 98), chronic cholecystitis (n = 118), or healthy gallbladders (n = 64). Multivariate analysis showed that CT findings of gallbladder distention greater than 4.0 cm (odds ratio [OR], 9.63; p < 0.01), mural striation (OR, 11.39; p < 0.01), and decreased mural enhancement (OR, 3.55; p < 0.05) independently predicted gangrenous cholecystitis. Using these CT features, the diagnosis of gangrenous cholecystitis was made with a specificity of 93.9% and 89.6% for readers 1 and 2, respectively, and accuracy of 90.9% and 87.0%, respectively. Good agreement was seen between the two readers with respect to gallbladder distention greater than 4.0 cm (κ = 0.77) and decreased mural enhancement (κ = 0.64). CONCLUSION: A markedly distended gallbladder associated with decreased wall enhancement is highly specific for gangrenous cholecystitis.

Imaging differentiation of phytobezoar and small-bowel faeces: CT characteristics with quantitative analysis in patients with small- bowel obstruction.

OBJECTIVE: The objective is to use multidetector computed tomography (MDCT) to differentiate phytobezoar impaction and small-bowel faeces in patients with small-bowel obstruction (SBO). METHODS: We retrospectively reviewed 91 consecutive SBO patients with surgically proven phytobezoars (n = 31) or adhesion with small-bowel faeces (n = 60). Two readers blinded to the diagnosis recorded the following MDCT features: degree of obstruction, transition point, mesenteric fatty stranding, intraperitoneal fluid, air-fluid level, pneumatosis intestinalis, and portal venous gas. MDCT measurements of the food debris length, attenuation, luminal diameter, and wall thickness of the obstructed bowel were also compared. RESULTS: A higher grade of obstruction with an absence of mesenteric fatty stranding and intraperitoneal fluid was more commonly seen in the phytobezoar group than in the small-bowel faeces group (p < 0.01). The food debris length (phytobezoar, 5.7 ± 2.8 cm; small-bowel feces, 20.3 ± 7.9 cm, p < 0.01) and mean attenuation (phytobezoar, -59.6 ± 43.3 Hounsfield units (HU); small-bowel faeces, 8.5 ± 7.7 HU, p <0.01) were significantly different between the two groups. The ROC curve showed that food debris length <9.5 cm and mean attenuation value < -11.75 HU predicted phytobezoar impaction. CONCLUSIONS: MDCT features with measurements of the food debris length and mean attenuation assist the differentiation of phytobezoar impaction and small-bowel faeces. KEY POINTS: • MDCT examination helps to differentiate phytobezoar and small-bowel faeces. • A higher grade of obstruction is commonly associated with phytobezoar impaction. • Mesenteric fatty stranding and intraperitoneal fluid are frequently associated with small-bowel faeces. • Quantitative measurement of the obstructed bowel adds the diagnostic accuracy.

Prognostic potential of initial CT changes for progression-free survival in gefitinib-treated patients with advanced adenocarcinoma of the lung: a preliminary analysis.

OBJECTIVES: We aimed to determine whether initial tumour responses measured during short-term follow-up computed tomography (CT) examinations after baseline examinations would correlate with clinical outcomes in patients with non-small cell lung cancer (NSCLC) who received epidermal growth factor receptor (EGFR)-targeted therapy. METHODS: A total of 86 gefitinib-treated patients with advanced adenocarcinoma of the lung were retrospectively reviewed. All patients underwent baseline and short-term follow-up CT examinations. The new response criteria (NRC) by Lee et al. were used for the response evaluations. A Cox proportional hazards multiple regression model and Kaplan-Meier survival analyses were used to evaluate correlations between the initial tumour changes and progression-free and overall survival (PFS, OS). RESULTS: Better separation and smaller p values were observed for both PFS and OS when good and poor disease responses (as defined by NRC) were compared after excluding tumours with characteristic morphologies. Early tumour changes correlated with PFS in a size-dependent manner. Moreover, a stronger association was observed between size changes and PFS when characteristic morphology was also considered. CONCLUSIONS: Initial changes in tumour size during short-term post-treatment CT examinations could act as a potential prognostic imaging surrogate for PFS in gefitinib-treated patients with advanced adenocarcinoma of the lung. KEY POINTS: • Initial responses to gefitinib on computed tomography significantly correlate with clinical outcomes. • Regardless of morphology, size decrease greater than 30 % predicts prolonged progression-free and overall survival. • Combination of size and morphological changes yields prognostic independence regarding progression-free survival.

Transient respiratory motion artifact during arterial phase MRI with gadoxetate disodium: risk factor analyses.

OBJECTIVE: The purpose of this article is to identify risk factors for arterial phase respiratory motion artifact in gadoxetate disodium-enhanced liver MRI. MATERIALS AND METHODS: We retrospectively identified 220 consecutive patients who underwent 357 MRI examinations, including 68 patients who underwent multiple MRI examinations, with gadoxetate disodium between 2010 and 2013. The arterial phase timing was determined by a fluoroscopic-triggering method. T1-weighted unenhanced and contrast-enhanced images were reviewed to record respiratory motion artifact, which was graded on a 5-point scale. Arterial phase transient severe motion was considered to be present if the motion score was 4 or greater on the arterial phase images and if the motion scores were 2 or less on unenhanced and other contrast-enhanced images. Patient characteristics and risk factors (e.g., age, sex, weight, body mass index, medical and radiologic history, allergy to MRI and iodinated contrast agents, estimated glomerular filtration rate, Child-Pugh class, and findings on current MRI examinations) were recorded. We included a history of transient severe motion on prior MRI as a predictor variable. We performed univariable and multivariable analysis using the generalized estimated equations to adjust for clustering. RESULTS: The incidence of transient severe motion was 12.9% (46/357). On univariable analysis, a history of transient severe motion (odds ratio [OR] = 3.31; p = 0.04) on prior MRI and allergy to iodinated contrast agent (OR = 3.03; p = 0.01) statistically significantly increased the incidence of transient severe motion for a given MRI examination. These associations were not seen on multivariable analysis (adjusted OR = 2.38 and p = 0.23 for a history of transient severe motion; adjusted OR = 1.93 and p = 0.23 for allergy to CT contrast agent). CONCLUSION: The occurrence of transient severe motion during arterial phase MRI with gadoxetate disodium is 12.9% and is poorly predicted on the basis of risk factors.

Breast Nonmass Enhancement Detected with MRI: Uility and Lesion Characterization with Second-Look Ultrasonography.

The purpose of this study was to verify the utility of second-look ultrasonography (US) in evaluating nonmass enhancement (NME) lesions detected on breast magnetic resonance imaging (MRI) by analysing its correlation and imaging features. From July 2008 to June 2012, 102 consecutive MRI-detected NME lesions were subsequently evaluated with US. Lesions were evaluated according to the established Breast Imaging Reporting and Data System (BI-RADS) lexicon. The correlation between MRI-detected NME lesion characteristics, lesion size, histopathological findings and features at second-look US were analysed. Second-look US identified 44/102 (43%) of the NME lesions revealed by MRI. A US correlate was seen in 34/45 (76%) malignant lesions compared with 10/57 (18%) benign lesions (p < 0.0001). The likelihood of malignancy was significantly higher for NME lesions with a US correlate than lesions without: 34/44 (77%) versus 11/58 (19%) (p < 0.0001). The malignancy of the 44 (43%) MRI-detected NME lesions with a US correlate was significantly associated with US lesion margins and BI-RADS categories (p = 0.001 and 0.002 respectively). Second-look US of MRI-detected NME lesions is useful for decision-making as part of the diagnostic workup. Familiarity with the US features associated with malignancy improves the utility of US in the workup of these NME abnormalities.

Radiofrequency ablation of hepatic metastases: factors influencing local tumor progression.

BACKGROUND: Although radiofrequency ablation (RFA) of nonresectable hepatic metastases has gained wide acceptance by showing survival benefit in selected patients, scattered reports are available regarding risk factors of local control of percutaneous RFA. The purpose of this study was to prospectively evaluate the factors influencing local tumor progression after percutaneous RFA of hepatic metastases. METHODS: Sixty-nine hepatic metastatic lesions in 54 patients were treated by percutaneous RFA. Efficacy was evaluated by contrast-enhanced computed tomography or magnetic resonance imaging at 1 month after ablation, then at 3-month intervals for the first year and biannually thereafter. RESULTS: The results of the log-rank test showed that tumor size of <3 cm (p = 0.024) and the absence of tumor contiguous with large vessels (p = 0.002) significantly correlated with local control for hepatic metastases. Cox regression analysis showed that the tumor size <3 cm and the absence of tumor contiguous with large vessels were independent factors (p = 0.055 and 0.009, respectively). The results of the log-rank test showed that neither the threshold post-ablation margin of 1.8 cm (p = 0.064) nor the presence of a tumor with subcapsular location (p = 0.134) correlated with the success of local control. CONCLUSIONS: Percutaneous RFA is more effective in achieving local control in patients with hepatic metastases when the tumor size is <3 cm and not contiguous with large vessels.

Value of ¹8F-FDG uptake on PET/CT and CEA level to predict epidermal growth factor receptor mutations in pulmonary adenocarcinoma.

PURPOSE: The identification of the mutation status of the epidermal growth factor receptor (EGFR) is important for the optimization of treatment in patients with pulmonary adenocarcinoma. The acquisition of adequate tissues for EGFR mutational analysis is sometimes not feasible, especially in advanced-stage patients. The aim of this study was to predict EGFR mutation status in patients with pulmonary adenocarcinoma based on (18)F-fluorodeoxyglucose (FDG) uptake and imaging features in positron emission tomography/computed tomography (PET/CT), as well as on the serum carcinoembryonic antigen (CEA) level. METHODS: We retrospectively reviewed 132 pulmonary adenocarcinoma patients who underwent EGFR mutation testing, pretreatment FDG PET/CT and serum CEA analysis. The associations between EGFR mutations and patient characteristics, maximal standard uptake value (SUVmax) of primary tumors, serum CEA level and CT imaging features were analyzed. Receiver-operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors. RESULTS: EGFR mutations were identified in 69 patients (52.2 %). Patients with SUVmax ≥6 (p = 0.002) and CEA level ≥5 (p = 0.013) were more likely to have EGFR mutations. The CT characteristics of larger tumors (≥3 cm) (p = 0.023) and tumors with a nonspiculated margin (p = 0.026) were also associated with EGFR mutations. Multivariate analysis showed that higher SUVmax and CEA level, never smoking and a nonspiculated tumor margin were the most significant predictors of EGFR mutation. The combined use of these four criteria yielded a higher area under the ROC curve (0.82), suggesting a good discrimination. CONCLUSION: The combined evaluation of FDG uptake, CEA level, smoking status and tumor margins may be helpful in predicting EGFR mutation status in patients with pulmonary adenocarcinoma, especially when the tumor sample is inadequate for genetic analysis or genetic testing is not available. Further large-scale prospective studies are needed to validate these results.

The association of haemoglobin A1C levels with the clinical and CT characteristics of Klebsiella pneumoniae liver abscesses in patients with diabetes mellitus.

OBJECTIVES: To compare the characteristics of Klebsiella pneumoniae liver abscesses (KPLA) in diabetic patients with different levels of glycaemic control. METHODS: The institutional review board approved this retrospective study. A total of 221 patients with KPLA were included. Clinical features of KPLA were compared. We divided the 120 diabetic patients with KPLA into three subgroups based on haemoglobin A1C (HbA1C) concentration (good, HbA1C ≤ 7.0 %; suboptimal, 7.0 % < HbA1C ≤ 9.0 %; poor, HbA1C > 9.0 %). In this study, we used a semiautomated quantitative method to assess the gas and total abscess volumes in KPLA. Statistical analysis was performed with the chi-squared test and one-way analysis of variance. RESULTS: The mortality rate did not significantly differ between the nondiabetic and diabetic groups. However, patients with poor glycaemic control had significantly more complications and therefore a longer hospital stay (P < 0.05). In our study, CT and quantitative analyses found that patients in the group with poor glycaemic control had a significantly higher incidence of gas formation and hepatic venous thrombophlebitis and a higher gas-to-abscess volume ratio than patients with suboptimal and good glycaemic control (P < 0.05). CONCLUSIONS: Diabetic patients with a high HbA1C concentration (>9.0 %) have an association with hepatic venous thrombophlebitis, gas formation and metastatic infection complications associated with KPLA. KEY POINTS: • Poorly controlled diabetes is associated with complications in Klebsiella pneumoniae liver abscesses. • Hepatic venous thrombosis and gas are important signs of metastatic infection. • Hepatic venous thrombophlebitis is associated with 72.7 % of metastatic infections.

Histological grade of hepatocellular carcinoma correlates with arterial enhancement on gadoxetic acid-enhanced and diffusion-weighted MR images.

PURPOSE: To retrospectively determine the correlation between heptic tumor signal intensity on gadoxetic acid-enhanced and diffusion-weighted MR images and histopathological grading of hepatocellular carcinoma (HCC). METHODS: We retrospectively reviewed the MR images of 79 patients with 141 surgically resected HCCs. The signal intensity and its relationship with histopathological grade were assessed. We measured the apparent diffusion correlation (ADC) values and calculated arterial enhancement ratios, washout ratios, and relative intensity ratios of HCCs relative to the surrounding liver parenchyma in gadoxetic-enhanced MR images in order to determine their relationship to the histological grade. RESULTS: Morphological evaluation showed that larger tumor size and extrahepatic extension were associated with higher histologic grade (p < 0.01). Multivariate logistic regression showed that low ADC value and low relative intensity ratio in the arterial phase (RIRa) predict high histological grade. ADC value (cut-off 1.7 × 10(-3) mm(2)/s, sensitivity 82.4%, specificity 83.2%) was the best predictor of well-differentiated HCC, and RIRa (cut-off 0.93, sensitivity 81.4%, specificity 93.9%) was superior to ADC for predicting poorly differentiated HCC. CONCLUSION: Relative low arterial enhancement on gadoxetic acid-enhanced MR images and low ADC are predictive of worse histological grades of HCC.

Heterogenous liver parenchymal enhancement in CT is a favorable prognosis of HCC after hepatic resection.

This study aimed to define the role of heterogeneity of liver parenchymal enhancement on computed tomography (CT) in the survival of patients with hepatocellular carcinoma (HCC) after hepatic resection. The medical records of patients with HCCs and who had undergone hepatic resection were retrospectively reviewed. The standard deviation (SD) of three different enhanced CT scan images was used to estimate the heterogeneity of liver parenchymal enhancement: SD of > 5.6, heterogenous enhancement, and SD of ≤ 5.6, homogeneous enhancement. A total of 57 patients had heterogenous enhancement, and 143 patients had homogeneous enhancement. The patients with heterogenous enhancement had longer disease-free and overall survivals than those with other enhancements (log-rank test, P < 0.001 and P = 0.036). The pathologic exam showed that heterogenous enhancement tended to develop septa in the peritumoral liver tissues. The prevalence of CD8+ cells was significantly higher in the peritumor liver tissues with septa than in those without (0.83% vs. 0.26%, P < 0.001). The peritumoral CD8/Foxp3 ratio was higher in the liver tissues with septa than in those without (1.22 vs. 0.47, P = 0.001), and patients with CD8/Foxp3 of > 0.8 had better overall survival than those with CD8/Foxp3 of ≤ 0.8 (log-rank test, P = 0.028). In conclusion, patients who had undergone hepatic resection with a heterogenous liver parenchymal enhancement tended to develop hepatic septa, which was associated with a higher CD8/Foxp3 ratio and longer survival. Therefore, contrast-enhanced CT scans might be a useful tool to predict the outcome of HCC.