The connectivity patterns among the DMN nodes when the brain is resting are still in great debate. Among the unknowns is whether a dominant node exists in the network and if any, how does it influences the other nodes. Resting state functional magnetic resonance imaging (rsfMRI) was utilized in data acquisition on 25 healthy male and female participants. The DMN nodes selected were posterior cingulate cortex (PCC), bilateral inferior parietal cortex (IPL) and medial prefrontal cortex (mPFC). Fully connected causal models were constructed comprising four DMN nodes. The time invariant covariance of the random fluctuations between nodes was then estimated to obtain the effective connectivity (EC) between the DMN nodes. The EC values among the DMN nodes were averaged over the participants using Bayesian Parameter Averaging (BPA). All the DMN nodes have self-inhibitory dynamics. All connections between nodes were significant (P > 0.9) with a condition for any of the two nodes, one node inhibited the others. The PCC which exhibited the highest signal intensity was in fact inhibited by others. Inter-hemispheric RIPC to LIPC connections acted the same way, with excitatory LIPC to RIPC and inhibitory RIPC to LIPC connections. The results also showed a stronger mPFC to RIPC connection in the right hemisphere (as compared to mPFC to LIPC connection in the left hemisphere) and a weaker PCC to RIPC connection in the right hemisphere (as compared to PCC to LIPC connection in the left hemisphere). PCC can be regarded as a dominant node among the four nodes, being connected to all other nodes in different ways. All the four nodes were significantly activated and connected to each other even though the brain was in a state of resting.
Alpha-fetoprotein (AFP)-producing carcinoma which microscopically mimics hepatocellular carcinoma (HCC) is a rare entity known as hepatoid adenocarcinoma (HC). They usually arise in the stomach, while oesophageal origin is only occasionally encountered. This tumour is highly aggressive and is associated with a poor prognosis. They frequently metastasise to the liver, thus giving rise to diagnostic difficulty, especially in cases where simultaneous oesophageal and liver mass are present. We reported a case of oesophageal hepatoid carcinoma with multiple liver metastasis, that was associated with an increased serum AFP. The distinction between HCC and HC is important because HC is more aggressive and has a poorer prognosis with limited therapeutic options. An extensive diagnostic work-up which include a thorough clinical history, radiological investigations (computed tomography or magnetic resonance imaging) as well as tissue biopsy supported by a panel of immunohistochemical markers are necessary to aid in the diagnosis of HC.
Introduction White matter hyperintense (WMHI) lesions are the most common finding in magnetic resonance imaging (MRI) of the brain in patients with systemic lupus erythematosus (SLE). Objective The objective of this article is to determine the clinical factors associated with an increase in WMHI lesion load among SLE patients. Method A total of 83 SLE patients with MRI of the brain from National University of Malaysia Medical Centre were included. The WMHI lesion load was determined using the Scheltens score and Fazekas scale, and their distribution was divided into the deep white matter (DWMHI) and periventricular (PVH) regions. The clinical correlates of WMHI lesions were initially determined using univariate analyses and subsequently multivariable regression analyses were performed to determine the independent factors of increased WMHI lesion load. Results MRI of the brain of 46 patients who had WMHI lesions were compared with 37 patients with normal MRI. We found significant association between the presence of WMHI lesions and age, presence of cerebral infarcts, positive antiphospholipid antibody (aPL), active disease, neuropsychiatric lupus (NPSLE) and disease damage. Age, SLEDAI scores, cerebral infarcts and disease damage were significantly associated with higher DWMHI and PVH Scheltens scores. Meanwhile, patients with active lupus nephritis (LN), lower serum albumin and more severe proteinuria were associated with larger Fazekas WMHI lesions. Multivariable regression analysis revealed that the independent factors associated with presence of WMHI lesions were positive aPL and SLEDAI scores ( p