Case report: The promising application of dynamic functional connectivity analysis on an individual with failed back surgery syndrome.

Failed back surgery syndrome (FBSS), a chronic neuropathic pain condition, is a common indication for spinal cord stimulation (SCS). However, the mechanisms of SCS, especially its effects on supraspinal/brain functional connectivity, are still not fully understood. Resting state functional magnetic resonance imaging (rsfMRI) studies have shown characteristics in patients with chronic low back pain (cLBP). In this case study, we performed rsfMRI scanning (3.0 T) on an FBSS patient, who presented with chronic low back and leg pain following her previous lumbar microdiscectomy and had undergone permanent SCS. Appropriate MRI safety measures were undertaken to scan this subject. Seed-based functional connectivity (FC) was performed on the rsfMRI data acquired from the FBSS subject, and then compared to a group of 17 healthy controls. Seeds were identified by an atlas of resting state networks (RSNs), which is composed of 32 regions grouped into 8 networks. Sliding-window method and k-means clustering were used in dynamic FC analysis, which resulted in 4 brain states for each group. Our results demonstrated the safety and feasibility of 3T MRI scanning in a patient with implanted SCS system. Compared to the brain states of healthy controls, the FBSS subject presented very different FC patterns in less frequent brain states. The mean dwell time of brain states showed distinct distributions: the FBSS subject seemed to prefer a single state over the others. Although future studies with large sample sizes are needed to make statistical conclusions, our findings demonstrated the promising application of dynamic FC to provide more granularity with FC changes associated with different brain states in chronic pain.

CT angiography and MRI imaging features do not predict the tumor type and grade of feline injection site sarcoma.

Computed tomographic angiography (CTA) and magnetic resonance imaging (MRI) have been described as methods for preoperative surgical planning in cats with feline injection site sarcomas (FISS), however, few published studies have compared these modalities. The objective of this retrospective, secondary analysis study was to determine if imaging features of FISS on CTA and MRI are predictive of neoplastic peritumoral projections. Archived data from a previous prospective study were retrieved for 10 cats with FISS. All cats had been evaluated in a single anesthetic episode with MRI and dual phase CT (CTA) imaging followed by surgical removal. Histopathological grading and targeted histopathology of imaging-identified peritumoral projections were performed. Two observers evaluated the CTA and MRI studies for FISS shape, margination, size, enhancement pattern, postcontrast uniformity, pre- and postcontrast margination, the number of muscles involved, mass mineralization, and bone lysis. Metal was present in the imaging field of three of 10 cats, resulting in one nondiagnostic MRI. Peritumoral projections were detected in all cats with both imaging modalities, and most were benign. At least one neoplastic peritumoral projection was detected in six cats using MRI, five cats using CTA, and three cats with both modalities. Higher grade FISS were larger than low grade using MRI, and FISS were larger using MRI. Other FISS imaging features using MRI and CTA were similar. Findings supported use of either MRI or CTA for detecting neoplastic peritumoral projections in cats with FISS. Authors recommend CTA for cats with known metallic objects in the scan field.

Identification of unique DNA sequences present in highly virulent 2009 Alabama isolates of Aeromonas hydrophila.

In 2009, a disease outbreak caused by Aeromonas hydrophila occurred in 48 catfish farms in West Alabama, causing an estimated loss of more than 3 million pounds of food size channel catfish. Virulence studies have revealed that the 2009 isolates of A. hydrophila are at least 200-fold more virulent than a 1998 Alabama isolate AL98-C1B. However, up to now, no molecular markers have been identified to differentiate the highly virulent 2009 isolates from other isolates of A. hydrophila. To understand the genetic differences between the highly virulent 2009 isolates and the less virulent AL98-C1B at molecular level, PCR-select bacterial genome subtractive hybridization was used in this study. A total of 96 clones were selected from the subtractive genomic DNA library. Sequencing results revealed that the 96 clones represented 64 unique A. hydrophila sequences. Of the 64 sequences, three (hypothetical protein XAUC_13870, structural toxin protein RtxA, and putative methyltransferase) were confirmed to be present in the three virulent 2009 Alabama isolates but absent in the less virulent AL98-C1B. Using genomic DNAs from nine field isolates of A. hydrophila with different virulence as templates, two sequences (hypothetical protein XAUC_13870 and putative methyltransferase) were found to be only present in highly virulent A. hydrophila isolates, but absent in avirulent isolates.