ABSTRACT
<p><b>OBJECTIVE</b>To investigate the feasibility and image quality of coronary artery angiography with 640-slice CT system in the pacemaker patients.</p><p><b>METHODS</b>ECG-triggered 640-slice CT coronary angiography was performed in 16 pacemaker patients. Image quality of the fifteen coronary segments and metal-related artifact originating from pacemaker were assessed by two experienced radiologists in consensus. Image quality was assessed using a 4-point grading scale. ECG trigger information was recorded.</p><p><b>RESULTS</b>The rate of available diagnostic images was 99.07% (Grade 1 in 83.64%, Grade 2 in 15.42%, Grade 3 in 0.47% and Grade 4 in 0.47% of patients, respectively). Image quality and the effect of streak artifact were similar between the high heart rate group and low heart rate group (P > 0.05) and between normal pacing group and arrhythmia group (P > 0.05). In coronary MSCT angiography, streak artifact of the pacemaker can render segments of the coronary artery uninterpretable, especially on S1, S2, S3, S4 and S8 segments of the coronary artery. Small shifts in the reconstruction window resulted in significance reduction of streak artifact (χ(2) = 151.818, P < 0.01).</p><p><b>CONCLUSIONS</b>640-slice gated CT coronary angiography could provide excellent image quality for patients with pacemaker. The streak artifact induced by pacemaker on some segments of the coronary artery could be improved by small shifts in the reconstruction window.</p>
Subject(s)
Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Coronary Angiography , Methods , Coronary Disease , Diagnostic Imaging , Therapeutics , Heart Rate , Pacemaker, Artificial , Tomography, X-Ray ComputedABSTRACT
Objective To explore the distribution rule of metastatic lymph node in nasopharyngeal carcinoma (NPC) by magnetic resonance imaging (MRI).Methods 315 histopathologically proved NPC patients were studied retrospectively.All patients had had their nasopharynx scanned by MRI with plain and contrast enhanced sequences.The distribution of lymph node was divided into six cervical levels plus retro- pharyngeal nodes(RN) according to RTOG guidelines proposed in 2003.Results 254 out of 315 patients (80.6%) had lymph node involvement,with 81 in the right neck alone,72 left neck alone,and 101 both necks;73 in RN alone,21 neck node alone,and 160 both necks and RN node.Skip metastasis was found in only 4 patients (1.6%).There was significant difference in BN metastasis between the primary tumor be- ing located merely on the superior/posterior wall and lateral wall (78% vs 49%,P＜0.01).The incidence of lymph node metastasis in T1,T2,T3 and T4 patients was 73.5%,91.2%,71.9%,73.5% (P＞0.05), respectively,without significant difference between early or advanced T stage in node distribution (P＞0.05).Conclusions The incidence of lymph node metastasis is high in nasopharyngeal carcinoma,with retropharyngeal node being the most commonly involved,but the incidence of skip metastasis is very low. There is no significant difference between T stage and the incidence of lymph node metastasis.So is the dis- tribution of metastatic node.