Assessment of small hepatocellular carcinoma: perfusion quantification and time-concentration curve evaluation using color-coded and quantitative digital subtraction angiography.

To explore the role of quantitative digital subtraction angiography (QDSA) in the diagnosis of small hepatocellular carcinoma (HCC).Between November 2015 and November 2017, all patients who underwent chemoembolization for HCC were retrospectively reviewed. Patients with tumors measuring more than 5 cm or evident post-processing imaging artifacts were excluded. Images were post-processed using the QDSA technique. Regions of interest were manually drawn on proper hepatic artery (as a reference), target HCC and peritumoral liver. Time-concentration curves and flow parameters of the peak ratio, subtracted time-to-peak (TTP), and area under the curve (AUC) ratio was obtained and analyzed.A total of 146 HCCs (mean diameter, 1.6 cm) of 71 cirrhotic patients (54 men, 17 women; mean age, 67.7 years) were enrolled. Compared with liver parenchyma, HCCs showed an increased and more rapid flow (peak ratio, AUC ratio, subtracted TTP, and wash-in slope; all P <.001). Compared with untreated HCCs, chemoembolized HCCs showed a slower flow (subtracted TTP and wash-in slope, P = .004 and .002, respectively). HCCs with a typical enhancement pattern on computed tomography (CT) or magnetic resonance imaging (MRI) had a trend toward Type III (washout pattern) time-concentration curves (P <.001). Chemoembolized HCCs had a trend toward Type II (plateau pattern) time-concentration curves (P = .005).QDSA technology can be used to quantify perfusion measurements of HCC and hepatic parenchyma and to assess perfusion changes after HCC chemoembolization.

Contextual interference enhances motor learning through increased resting brain connectivity during memory consolidation.

Increasing contextual interference (CI) during practice benefits learning, making it a desirable difficulty. For example, interleaved practice (IP) of motor sequences is generally more difficult than repetitive practice (RP) during practice but leads to better learning. Here we investigated whether CI in practice modulated resting-state functional connectivity during consolidation. 26 healthy adults (11 men/15 women, age = 23.3 ±â€¯1.3 years) practiced two sets of three sequences in an IP or RP condition over 2 days, followed by a retention test on Day 5 to evaluate learning. On each practice day, functional magnetic resonance imaging (fMRI) data were acquired during practice and also in a resting state immediately after practice. The resting-state fMRI data were processed using independent component analysis (ICA) followed by functional connectivity analysis, showing that IP on Day 1 led to greater resting connectivity than RP between the left premotor cortex and left dorsolateral prefrontal cortex (DLPFC), bilateral posterior cingulate cortices, and bilateral inferior parietal lobules. Moreover, greater resting connectivity after IP than RP on Day 1, between the left premotor cortex and the hippocampus, amygdala, putamen, and thalamus on the right, and the cerebellum, was associated with better learning following IP. Mediation analysis further showed that the association between enhanced resting premotor-hippocampal connectivity on Day 1 and better retention performance following IP was mediated by greater task-related functional activation during IP on Day 2. Our findings suggest that the benefit of CI to motor learning is likely through enhanced resting premotor connectivity during the early phase of consolidation.

Quantitative flow measurement after placing a flow diverter for a distal internal carotid artery aneurysm.

OBJECTIVES: To evaluate the differences in arterial flow after flow diverter placement using quantitative flow measurements based on digital subtraction angiography (DSA). METHODS: Between November 2013 and November 2015, all patients who had flow diverters placed for distal internal carotid artery (ICA) aneurysms were reviewed. Patients in whom the stent was placed across the ostia of the ophthalmic artery (OphA) and anterior choroidal artery (AChA) were enrolled. Five regions of interest were selected: the proximal ICA (as a reference), terminal ICA, middle cerebral artery (MCA), anterior cerebral artery (ACA), OphA, and AChA. The values of the peak, time-to-peak (TTP), and area under the curve (AUC) were analyzed using a quantitative DSA technique. RESULTS: The study enrolled 13 patients. The quantitative flow analysis showed improved flow in the terminal ICA (peak and AUC, p=0.036 and p=0.04, respectively), MCA (AUC, p=0.023), and ACA (AUC, p=0.006), and decreased flow in the OphA (peak and AUC, p=0.013 and p=0.005, respectively) and AChA (peak and subtracted TTP, p=0.023 and p=0.050, respectively) after flow diverter placement. Larger aneurysm volume was significantly correlated with decreased OphA flow after the procedure (peak and AUC, p=0.049 and p=0.037, respectively). Larger aneurysm volume also had a marginal correlation with increased distal ICA flow after the procedure, but this did not reach significance (peak and AUC, p=0.195 and p=0.060, respectively). CONCLUSIONS: Without using extra contrast medium or radiation dosages, color-coded DSA enables quantitative monitoring of the cerebral circulation after flow-diverting treatment.

Benefit of interleaved practice of motor skills is associated with changes in functional brain network topology that differ between younger and older adults.

Practicing tasks arranged in an interleaved manner generally leads to superior retention compared with practicing tasks repetitively, a phenomenon known as the contextual interference (CI) effect. We investigated the brain network of motor learning under CI, that is, the CI network, and how it was affected by aging. Sixteen younger and 16 older adults practiced motor sequences arranged in a repetitive or an interleaved order over 2 days, followed by a retention test on day 5 to evaluate learning. Network analysis was applied to functional MRI data on retention to define the CI network by identifying brain regions with greater between-region connectivity after interleaved compared with repetitive practice. CI effects were present in both groups but stronger in younger adults. Moreover, CI networks in younger adults exhibited efficient small-world topology, with a significant association between higher network centrality and better learning after interleaved practice. Older adults did not show such favorable network properties. Our findings suggest that aging affects the efficiency of brain networks underlying enhanced motor learning after CI practice.

[Retrospective investigation and analysis of endemic situation of schistosomiasis in hilly regions of Sichuan Province].

OBJECTIVE: To explore the rules of the changes of schistosomiasis infection and Oncomelania snails in areas where schistosomiasis transmission was controlled or interrupted or rebounded after interruption. METHODS: Qingbaijiang District, Longquanyi District and Xide County were selected and investigated retrospectively to collect schistosomiasis epidemiological information 10 years before they reached the criterion of transmission control and the subsequent years until 2008. The database of retrospective investigation was established for analyzing the trends and rules of changes of snail status and human infection status. RESULTS: In Qingbaijiang District, there was a positive correlation between density of living snails and snail area (r = 0.74, P < 0.01), and the infection rate of population was declining. In Longquanyi District, the snail area presented a declining trend. In Xide County, the human infection rate was positively correlated with snail area (R = 0.53, P < 0.01) and the density of living snails (r = 0.42, P < 0.05) respectively. CONCLUSIONS: The rebound of snail situation is always prior to the emerging of human infection, and it prompts that the rebound of snail situation can be considered one of the important indicators of early warning of the rebound of human infection situation in those places where schistosomiasis transmission was controlled or interrupted. Implementing comprehensive control of the snail habitat, as well as eliminating the potential infectious source is an important measure to consolidate the achievement of schistosomiasis control.