Cine-Computed Tomography for the Evaluation of Prosthetic Heart Valve Function.

BACKGROUND: After aortic valve replacement (AVR), suspected prosthetic valve dysfunction (mechanical or biological) may arise based on echocardiographic transvalvular velocities and gradients, leading to reoperative surgical intervention being considered. Our experience has found that 4-dimensional (space and time) image reconstruction of ECG-gated computed tomography, termed cine-CT, may be helpful in such cases. We review and illustrate our experience. METHODS: Twenty-seven AVR patients operated previously by a single surgeon (who performs >100 AVRs/year) were referred for repeat evaluation of suspected aortic stenosis (AS) based on elevated transvalvular velocities and gradients. The patients were fully evaluated by cine-CT. RESULTS: In all but 2 cases, the cine-CT strikingly and visually confirmed normal leaflet function and excursion, with no valve thrombosis, restriction by pannus, or obstruction by clot. In only 2 cases did cine-CT reveal decreased mechanical valve leaflet excursion. Repeat surgery was required in only 1 case while all other patients continued clinically without cardiac events. CONCLUSIONS: Echocardiography is an extraordinarily useful tool for the evaluation of prosthetic valve function. Increased pressure recovery beyond the valve and other factors may occasionally lead to exaggerated gradients. Cine-CT is emerging as an extremely valuable tool for further evaluation of suspected prosthetic valve AS. Our experience has been extremely helpful, as is shown in the dramatically reassuring images.

Evaluation of the four-dimensional motion of lung tumors during end-exhalation breath-hold conditions using volumetric cine computed tomography images.

BACKGROUND AND PURPOSE: This study was performed to evaluate the four-dimensional motion of lung tumors during end-exhalation (EE) breath-holding (BH) using cine computed tomography (CT) and investigate the correlation between tumor and surrogate marker motions. MATERIALS AND METHODS: This study included 28 patients who underwent stereotactic body radiation therapy at our institution and were capable of 15-20 s of EE BH within a ±1.5-mm gating window with external markers. During EE BH with cine CT, 21 s of continuous data were acquired using 320-row multislice CT. Displacements in the tumor position during EE BH were assessed in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions. Pearson's correlation coefficient (r) between tumor motions during EE BH and diaphragm/external marker motions was also determined. RESULTS: The mean absolute maximum displacements of the tumor position during EE BH were 1.3 (range: 0.2-4.0), 1.9 (range: 0.3-12.0), and 1.3 (range: 0.1-7.2) mm in the LR, AP, and SI directions, respectively. The displacement of the tumor position in the AP direction was weakly correlated (|r| < 0.4) with the external marker and diaphragm displacements in many cases (proportions of 50% and 46%, respectively). CONCLUSION: We found some cases showing substantial displacement in lung tumor positions during EE BH, especially in the AP direction. Because these tumor position displacements did not correlate with surrogate markers and were difficult to detect, we recommend pretreatment evaluation of the four-dimensional motions of tumors during BH using cine CT.

Application of 4D-CT Scanning in Differential Diagnosis of Arytenoid Subluxation and Vocal Fold Paralysis.

OBJECTIVE: To differentiate arytenoid subluxation and vocal fold paralysis by CT cine mode scanning combined with three-dimensional (3D) reconstruction image. METHODS: Seventy-six patients with suspected vocal fold dyskinesia were collected. All patients were examined being asked to inhale deeply and then make "Yi" sound continuously during CT scanning with cine mode. The optimal maximum opening and minimum closing phases of glottis were selected and 3D reconstruction images were performed. The length of vocal fold, the width of glottis, and the subglottal convergence angle, anteversion angle, elevation angle, valgus angle, and varus angle of cricoarytenoid joints were measured. Vocal fold deformation was divided into three types: type I, type II, and type III. Kappa test was used to compare the consistency between CT diagnosis and clinical diagnosis. Single-factor analysis of variance was used to analyze the statistical differences among arytenoid subluxation, vocal fold paralysis, and normal vocal fold. RESULTS: There was high consistency between CT diagnosis and clinical diagnosis (k = 0.731, P < 0.05), as well as significant differences in the opening width of glottis between type I and type III, the valgus and varus angles of cricoarytenoid joints between type I and type II or type III, and the subglottal convergence angles among the three types of vocal fold deformation. CONCLUSIONS: CT scanning with cine mode combined with 3D reconstruction can display the changes of larynx structures in vocal fold dyskinesia, and can be used for the differential diagnosis of arytenoid cartilage subluxation and vocal fold paralysis.

Cardiac cine CT approaching 1 mSv: implementation and assessment of a 58-ms temporal resolution protocol.

Clinical use of cardiac cine CT imaging is limited by high radiation dose and low temporal resolution. To evaluate a low radiation dose, high temporal resolution cardiac cine CT protocol in human cardiac CT and phantom scans. CT scans of a circulating iodine target were reconstructed using the conventional single heartbeat half-scan (HS, approx. 175 ms temporal resolution) and the 3-heartbeat multi-segment (MS, approx. 58 ms) algorithms. Motion artifacts were quantified by the root-mean-square error (RMSE). Low-dose cardiac cine CT scans were performed in 55 subjects at a tube potential of 80 kVp and current of 80 mA. Image quality of HS and MS scans was assessed by blinded reader quality assessment, left ventricular (LV) free wall motion, and LV ejection rate. Motion artifacts in phantom scans were higher in HS than in MS reconstructions (RSME 188 and 117 HU, respectively; p = 0.001). Median radiation dose in human scans was 1.2 mSv. LV late diastolic filling was observed more frequently in MS than in HS images (42 vs. 26 subjects, respectively; p < 0.001). LV free wall systolic motion was more physiologic and had less error in MS than in HS reconstructions (sum-of-squared errors 34 vs. 45 mm2, respectively; p < 0.001), and LV peak ejection rate was higher in MS than in HS reconstructions (166 vs. 152 mL/s, respectively; p < 0.001). Cardiac cine CT imaging is feasible at a low radiation dose of 1.2 mSv. MS reconstruction showed improved imaging of rapid motion in phantom studies and human cardiac CTs.

Preliminary Assessment of Dynamic Voice CT in Post-Airway Reconstruction Patients.

Objectives To compare the ability of the dynamic voice computed tomography (CT) scan to characterize laryngeal function in airway reconstruction patients vs bedside endoscopic nasopharyngolaryngoscopy and videolaryngostroboscopy. Study Design Case series with chart review. Settings Pediatric tertiary care center. Subjects and Methods Retrospective case series of children and young adults with a history of complex airway surgeries with subsequent dysphonia. We analyzed clinical data for all patients who underwent an airway reconstruction procedure between January 1, 2010, and April 30, 2016, and also had a dynamic voice CT and bedside endoscopic exam during the same period. Results Twenty-four patients were analyzed (4 male, 20 female) with a mean age of 15.1 years (95% confidence interval [CI], 12.9-17.22). Patients had a mean of 2.2 airway surgeries (95% CI, 1.8-2.6), with 62.5% of them being open procedures. Laryngotracheoplasty with a cartilage graft was the most common procedure (40.0%). The pattern of laryngeal closure could be detected in all cases with the dynamic CT scan (n = 24/24, 100%) compared to 87.5% (21/24) with the standard endoscopic examination ( P = .04). The location of gap closure could be detected in all cases (24/24) with the dynamic voice CT while 20.8% (5/24 patients) could not be rated with standard endoscopy/stroboscopy ( P = .02). Dynamic voice CT was able to assess the vertical closure pattern of the glottis 100% (24/24) while it could be detected in 83.3% (20/24) cases with endoscopic study ( P = .04). Conclusion Dynamic voice CT shows promise as an additional tool for evaluation of patients with a history of complex airway procedures by providing complementary information.

Utility of spiral and cine CT scanning in children suspected of foreign body in trachea / 中国医学影像技术

Objective To assess the value of spiral and cine CT for the diagnosis of foreign body in trachea in children. Methods Fifty-one consecutive pediatric patients suspected of aspirating radiolucent foreign body underwent chest radiography, 12 of them underwent three-dimensional spiral CT and cine CT scan within 24 h before rigid bronchoscopy. Results Rigid bronchoscopy showed foreign bodies in the main bronchus or bronchus intermedius of 42 patients, while spiral CT localized airway foreign bodies in the same patients. In the remaining 9 patients without foreign body found by rigid bronchoscopy, 6 were true-negative and 3 were false-positive on CT, making the overall sensitivity, specificity, accuracy, and positive and negative predictive values of CT scans was 100% (95% confidence interval, 91%-100%), 66.67% (29%-92%), 94.12% (64%-99%), 93.33% (81%-98%) and 100% (54%-100%), respectively. The cine CT scan correctly diagnosed 9 of 12 patients as true-positive and 3 as true-negative with identification of air trapping and secondary lung changes. Conclusion CT may be used in airway foreign body management of pediatric patients, especially with diagnostic dilemmas, and further prospective evaluations should be considered to assess its overall efficacy.