Screening of Colonic Tumors by Air-Inflated Magnetic Resonance (MR) Colonography

Purpose: To assess the accuracy of air-inflated magnetic resonance (MR) colonography for the detection of colonic lesions. Materials and Methods: A total of 36 patients underwent both colonoscopy and air-inflated MR colonography. Breath-hold sequences (volumetric interpolated breath-hold examination (VIBE) coronal, and half-Fourier acquisition single-shot turbo spin-echo (HASTE) axial and coronal, both supine and prone) were performed with a 1.5T scanner. The detection of colonic lesions by MR colonography was then correlated with the findings from the colonoscopy performed on the same day. Results: Two patients were unable to complete the MR colonography examination. Analysis was based on the results from 34 patients (17 males and 17 females, 38-70 years old, mean age = 54.9 years) who completed both examinations. MR colonography depicted two of two colonic tumors, one of one P4 (>2 cm) polyp, one of two P2 (0.5-1 cm) polyps, and two of 11 P1 (5 mm, air-inflated MR colonography yielded a sensitivity of 75%, specificity of 93.3%, accuracy of 91.2%, positive predictive value of 60%, and negative predictive value of 96.6%. Conclusion: Air-inflated MR colonography is a new technique that deserves further investigation.link_to_subscribed_fulltex

Magnetic resonance colonography in the detection of colonic neoplasm in high-risk and average-risk individuals

OBJECTIVES: Magnetic resonance colonography (MRC) is a new noninvasive diagnostic modality for colorectal cancer. However, the use of MRC in the detection of colorectal neoplasm in average-risk individuals remains unknown. This study determined the performance and the patient's preference of MRC in the detection of colorectal neoplasm. METHODS: Both high-risk (i.e., symptoms suggestive of colorectal neoplasm, positive fecal occult blood test, history of colorectal cancer in one or more first-degree relatives) and average-risk (i.e., asymptomatic individuals >50 yr) individuals were recruited. MRC was performed immediately prior to conventional colonoscopy (CC) by using air inflation without contrast. The finding on CC together with histology was used as a gold standard. Patients' pain and discomfort score were recorded immediately and 24 h after the procedure. They were also asked about their preferences for the two procedures. RESULTS: A total of 165 patients (79 average risk and 86 high risk) were recruited. Eight patients had incomplete MRC and one patient had failed CC. Of the remaining 156 patients, 4 were found to have colonic cancer and 31 were found to have 67 polyps. MRC correctly identified 3 cancers (sensitivity 75%, specificity 99.3%) and 4 patients with colonic polyps (sensitivity 12.9% and specificity 97.6%). Sensitivity of MRC tended to be lower in polyps <10 mm in size and in average-risk individuals. The mean procedure time of CC was significantly shorter than MRC (13.6 ± 6.7 vs 20.6 ± 2.7 min, p < 0.001). Although there was no significant difference in the pain and discomfort scores of the 2 procedures, 75% of patients preferred CC to MRC. CONCLUSIONS: The performance of MRC when used in the detection of colonic neoplasm in average-risk individuals is unsatisfactory.link_to_subscribed_fulltex

Left ventricular systolic asynchrony after acute myocardial infarction in patients with narrow QRS complexes

Background: The aim of the study was to assess the degree of left ventricular (LV) asynchrony after myocardial infarction (MI) in patients with a narrow QRS complex using tissue Doppler imaging (TDI) and correlate this with the site and extent of the infarction measured by contrast-enhanced magnetic resonance imaging (Ce-MRI). Methods: Echocardiography with TDI and Ce-MRI was performed within 6 days of acute MI in 47 patients and compared with 69 age-matched healthy volunteers. Regional myocardial velocities were assessed in 12 segments, and the corresponding systolic velocity (Sm), early diastolic velocity (Em), as well as the time to peak Sm (Ts) and time to peak Em (Te) were measured. To assess LV synchronicity, SDs of Ts (Ts-SD) and Te (Te-SD) of all 12 segments were computed. Location and size of infarct were confirmed by Ce-MRI with a 16-segment model. Results: All the patients had a normal QRS complex duration. The Ts-SD was significantly prolonged in the MI group when compared with controls (42.2 ± 13.7 vs 18.0 ± 7.0 milliseconds, P <. 001). The Ts-SD was longer in patients with anterior than inferior MI (46.8 ± 13.9 vs 34.6 ± 8.5 milliseconds, P =. 002). Stepwise multiple regression analysis revealed that infarct size was the main independent predictor of systolic asynchrony (B = 0.79, 95% CI 0.75-1.23, P <. 001). Asynchrony was not related to the transmurality of the infarction. Conclusions: Myocardial infarction has a significant impact on LV synchronicity even in those with a narrow QRS complex. The degree of LV systolic asynchrony is mainly determined by the infarct size and not transmurality. © 2005, Elsevier Inc. All rights reserved.link_to_subscribed_fulltex

Identification of neuroglycan C and interacting partners as potential susceptibility genes for schizophrenia in a Southern Chinese population

Chromosome 3p was reported by previous studies as one of the regions showing strong evidence of linkage with schizophrenia. We performed a fine-mapping association study of a 6-Mb high-LD and gene-rich region on 3p in a Southern Chinese sample of 489 schizophrenia patients and 519 controls to search for susceptibility genes. In the initial screen, 4 SNPs out of the 144 tag SNPs genotyped were nominally significant (P<0.05). One of the most significant SNPs (rs3732530, P=0.0048) was a non-synonymous SNP in the neuroglycan C (NGC, also known as CSPG5) gene, which belongs to the neuregulin family. The gene prioritization program Endeavor ranked NGC 8th out of the 129 genes in the 6-Mb region and the highest among the genes within the same LD block. Further genotyping of NGC revealed 3 more SNPs to be nominally associated with schizophrenia. Three other genes (NRG1, ErbB3, ErbB4) involved in the neuregulin pathways were subsequently genotyped. Interaction analysis by multifactor dimensionality reduction (MDR) revealed a significant two-SNP interaction between NGC and NRG1 (P=0.015) and three-SNP interactions betweenNRG1 and ErbB4 (P=0.009). The geneNGC is exclusively expressed in the brain. It is implicated in neurodevelopment in rats and was previously shown to promote neurite outgrowth. Methamphetamine, a drug thatmay induce psychotic symptoms, was reported to alter the expression of NGC. Taken together, these results suggest thatNGC may be a novel candidate gene, and neuregulin signaling pathways may play an important role in schizophrenia. © 2009 Wiley-Liss, Inc.link_to_subscribed_fulltex