Urodynamic 4D-CT evaluation: 320-row area detector CT scanner combined with PhyZiodynamics software analysis provides an innovative system to evaluate urinary flow and outlet obstructions

Detection of Dural Defect Localization Using 4-Dimensional Dynamic Computed Tomography Myelography for Patients with Superficial Siderosis

BACKGROUND

There are cases of superficial siderosis (SS) with spinal ventral fluid-filled collection in the spinal canal. In our previous study, the balanced steady-state free precession sequence magnetic resonance imaging is useful in identifying the location of dural defects. However, because of its narrow scan area and long scan time, it cannot easily detect the defect location in some patients with small dural defect. In this study, we applied 4-dimensional (4D) dynamic computed tomography (CT) imaging, including time-axis imaging, to myelography using the latest CT imaging equipment, which can perform short-time continuous imaging, to identify the dural defect site.

METHODS

Twenty SS patients with ventral fluid-filled collection in the spinal canal (9 males, 11 females; mean age 61.6 years) underwent 4D dynamic CT myelography. A 192-row helical CT (SOMATOM Force, SIEMENS, Munich, Germany) with high-speed scanning capability was used to obtain 9-11 scans per minute at low dose while passing contrast medium into the subarachnoid space. Then, contrast leakage sites were identified.

RESULTS

The contrast leakage sites could be identified in all 20 cases: C7/Th1, 2 cases; Th1/2, 5 cases; Th2/3, 9 cases; Th3/4, 1 case; Th5/6, 1 case; Th7/8, 1 case; and Th8/9, 1 case. Eighteen cases underwent surgical operation, and actual dural defects were confirmed at the contrast leakage sites. The mean ± standard deviation of leakage time from contrast agent injection was 19.0 ± 9.2 s.

CONCLUSIONS

The 4D dynamic CT myelography can be used to reliably identify the location of spinal fluid leakage. In SS cases, dural defects could be visualized in an average of 19 seconds.

Dynamic aortic changes during the cardiac cycle in patients with aortic valve disease analyzed by computed tomography combined with PhyZiodynamics software

BACKGROUND

Endovascular therapy for the ascending aorta is expected in the future, but the dynamic changes in the ascending aorta are unclear.

PURPOSE

The purpose of the present study was to evaluate dynamic changes in the aortic cross-sectional area and examine related determinants.

METHODS

The subjects included 75 patients (aortic regurgitation [AR] in 18 patients, aortic stenosis [AS] in 46 patients, and 11 controls) who underwent dynamic computed tomography (CT) prior to cardiac treatment. According to the centerline method, the cross-sectional areas of the ascending and descending aortas at the same level were analyzed. The rate of change from the minimum value to the maximum value in one heartbeat and peak rate of change in cross-sectional area (peak area change) were measured.

RESULTS

The rates of change of the ascending and descending aortas were 4.4% and 6.4% (P < 0.05) and the peak area change was 0.3 mm2/msec vs. 0.2 mm2/msec (P < 0.05), respectively. In both the ascending and descending aortas, the rate of change and the peak area change were significantly greater in the AR group than in the AS and control groups. Results of the multiple regression analysis showed that greater stroke volumes (SVs) were associated with greater change in the ascending aorta and a faster momentary expansion rate. Furthermore, it was observed that the momentary expansion rate declined with age.

CONCLUSION

The ascending aortic diameter changes significantly in one heartbeat and differs depending on AR, age, and SV.

TRIAL REGISTRATION NUMBER

17 - 006.

DATE OF REGISTRATION

May 29, 2017 Retrospectively registered.

Visualization of flow dynamics in the portal circulation using 320-detector-row computed tomography: a feasibility study

Multidetector row computed tomography (CT) scanners perform dynamic scanning and have a wide scan range. Time-resolved three-dimensional CT (i.e., 4D CT) has recently enabled visualization of flow in neurovascular vessels. We hypothesized that 4D CT technology would be a useful and non-invasive method for visualizing the flow dynamics of the portal circulation. The aim of this study was to evaluate the technical feasibility of 4D CT for visualizing flow dynamics in the portal circulation using 320-detector-row CT. 4D CT images of 18 consecutive patients with portal circulation including gastrorenal shunt were retrospectively evaluated for their ability to generate flow dynamics of the portal circulation. Flow dynamics could be visualized by 4D CT in 68 of the 72 vessels in the portal vein, splenic vein, superior mesenteric vein, and gastrorenal shunt. Flow direction could not be identified in four vessels, all of them being superior mesenteric veins. Flow direction was recognized on 4D CT in the 68 vessels of the portal circulation. A preliminary validation study revealed that flow direction of all 19 vessels in the portal circulation had concordance between 4D CT and color Doppler ultrasound. 4D CT could visualize flow dynamics of the portal circulation.

Four-dimensional CT excretory urography is an accurate technique for diagnosis of canine ureteral ectopia

Computed tomographic (CT) excretory urography is commonly used to investigate canine ureteral ectopia (UE). Modern technology allows time-resolved CT imaging (four-dimensional CT excretory urography [4D-CTEU]) over a distance exceeding the detector collimation. Objectives of this prospective, observational, diagnostic accuracy study were to evaluate the diagnostic accuracy of CT excretory urography (CTEU) and 4D-CTEU for UE in dogs with lower urinary tract signs, assess the influence of pelvis positioning, and to determine the significance of the ureterovesical junction (UVJ) angle for UE diagnosis. Thirty-six dogs, with a total of 42 normotopic ureters, 27 intramural ectopic ureters, and three extramural ectopic ureters, underwent CTEU and 4D-CTEU with randomized pelvis positioning. Randomized CTEU and 4D-CTEU studies were scored by two observers for ureteral papilla location and murality on a grading scheme. Interobserver agreement, sensitivity, and specificity for ureter topia status and diagnosis were calculated. Computed tomographic excretory urography showed moderate interobserver agreement for the left ureter and perfect for the right ureter, whereas 4D-CTEU showed bilateral nearly perfect agreement between both observers. When comparing CTEU versus confirmed diagnosis, there was a sensitivity and specificity of 73% and 90.2%, respectively, whereas 4D-CTEU showed a sensitivity and specificity of 97% and 94.6%, respectively. An obtuse UVJ angle is significantly more commonly observed in ectopic intramural than normotopic ureters and is significantly associated with increased diagnostic confidence of UE. The use of a wedge to angle the pelvis did not increase the diagnostic confidence in determining ureteral opening position. Four-dimensional CT excretory urography is an accurate and reliable diagnostic technique to investigate UE as cause of urinary incontinence in dogs that is slightly superior to CTEU.