ABSTRACT
OBJECTIVE: We wanted to evaluate the performance of prospective electrocardiogram (ECG)-gated axial scans for assessing coronary stents as compared with retrospective ECG-gated helical scans. MATERIALS AND METHODS: As for a vascular model of the coronary artery, a tube of approximately 2.5-mm inner diameter was adopted and as for stents, three (Bx-Velocity, Express2, and Micro Driver) different kinds of stents were inserted into the tube. Both patent and stenotic models of coronary artery were made by instillating different attenuation (396 vs. 79 Hounsfield unit [HU]) of contrast medium within the tube in tube model. The models were scanned with two types of scan methods with a simulated ECG of 60 beats per minute and using display field of views (FOVs) of 9 and 18 cm. We evaluated the in-stent stenosis visually, and we measured the attenuation values and the diameter of the patent stent lumen. RESULTS: The visualization of the stent lumen of the vascular models was improved with using the prospective ECG-gated axial scans and a 9-cm FOV. The inner diameters of the vascular models were underestimated with mean measurement errors of -1.10 to -1.36 mm. The measurement errors were smaller with using the prospective ECG-gated axial scans (Bx-Velocity and Express2, p < 0.0001; Micro Driver, p = 0.0004) and a 9-cm FOV (all stents: p < 0.0001), as compared with the other conditions, respectively. The luminal attenuation value was overestimated in each condition. For the luminal attenuation measurement, the use of prospective ECG-gated axial scans provided less measurement error compared with the retrospective ECG-gated helical scans (all stents: p < 0.0001), and the use of a 9-cm FOV tended to decrease the measurement error. CONCLUSION: The visualization of coronary stents is improved by the use of prospective ECG-gated axial scans and using a small FOV with reduced blooming artifacts and increased spatial resolution.
Subject(s)
Contrast Media , Coronary Angiography , Coronary Stenosis , Coronary Vessels , Electrocardiography/methods , Image Processing, Computer-Assisted/methods , Models, Cardiovascular , Observer Variation , Phantoms, Imaging , Radiographic Image Enhancement/methods , Stents , Tomography, Spiral Computed/methodsABSTRACT
@#Objective To use the multi-slice CT(MSCT)cerebral perfusion imaging and CT angiography(CTA)in the clinical diagnosis of transient ischemic attack(TIA).Methods 20 cases with transient ischemic attack within 48 h were examined with 16-slice CT perfusion imaging(CTPI)and CTA in head and neck.The interesting regional cerebral blood flow(rCBF),cerebral blood volume(rCBV)and the time to peak(rTP)were analyzed.Results The rTP of affected side delay compared with that of the healthy(t=3.04,P=0.008).CTA showed the responsible vascular stenosis or occlusion in varying degrees.There was not significant correlationship between rTP and vascular stenosis(r=0.32,P=0.17).Conclusion Cerebral perfusion imaging and head and neck CTA can provide valuable information for diagnosis and treatment of TIA.
ABSTRACT
A 16-year-old high school boy experienced intermittent claudication of his left lower limb during boxing training. Physical examination revealed a cold left foot and diminished pulse. A 64-row multi-slice CT (MSCT) demonstrated lateral shift and severe stenosis of the left popliteal artery due to malposition of the medial head of the gastrocnemius muscle. A diagnosis of popliteal artery entrapment syndrome (Delaney type II) was established and a surgical correction was planned. During surgery, since the artery was found to be compressed but not occluded, we simply released the popliteal artery by division of the medial head of the gastrocnemius and abnormal flips of muscle. The postoperative ankle brachial pressure index rose from “not measurable” to 1.22. MSCT was useful to characterize this anomaly by expressing the precise anatomical relation of muscle, bone and artery, which was a good guide for an appropriate surgical intervention.