Coronary stent imaging with dual-source CT: assessment of lumen visibility using different convolution kernels and postprocessing filters.

BACKGROUND: Assesment of the coronary arteries after stent placement using coronary computed tomography angiography (CCTA) currently requires reconstruction of images with soft kernels for the assessment of atherosclerotic plaques and dedicated edge enhancing kernels for the evaluation of the stent lumen. PURPOSE: To evaluate a two-dimensional filter tool that provides instant postprocessing of images reconstructed with soft kernels into edge-enhanced images and vice versa and thus may eliminate the need for two separate reconstrcutions for the assessment of coronary artery stents using CCTA. MATERIAL AND METHODS: Twenty stents with a diameter of 3.0 mm placed in a vascular phantom were scanned with a dual-source CT using standard parameters. Images were reconstructed with a soft B30f and an edge-enhancing B46f kernel and postprocessed with the corresponding filter algorithm (F30 for B30f images; F46 for B46f images). The resulting four data-sets were evaluated for lumen visibility, intraluminal attenuation, and image noise by two independent readers. Results were validated in vivo against invasive coronary angiography in data-sets from patients with coronary artery stents. RESULTS: Average intraluminal attenuation was 552.6 HU, 527.3 HU, 207.9 HU, and 267.5 HU for B30f, F30, B46f, and F46 images, respectively (P < 0.0001). Average image noise was 11.3, 10.6, 19.2, and 15.0 HU, respectively (P < 0.0001). The visible stent diameter was significantly higher in the B46f (59.6%) and F46 images (54%) compared to the B30f (48.3%) and F30 (51.5%) images (P < 0.0001). In the patient study, lumen assessability was significantly better in B46f images than in F46 images. Sensitivity for stenosis detection was best in the original B46f images with a sensitivity of 67% and a specificity of 94%. CONCLUSION: The postprocessing filter reduces image noise, however currently it does not offer an alternative to image reconstruction using the edge-enhancing kernels for the evaluation of the stent lumen.

Automatic MDCT injectors: hygiene and efficiency of disposable, prefilled, and multidosing roller pump systems in clinical routine.

OBJECTIVE: This study evaluated three different injection systems with regard to microbiological contamination, time efficiency, and user handling during a clinical routine. SUBJECTS AND METHODS: A total of 825 patients were included. A double-syringe contrast injector with disposable syringes (system A; n = 150) and one that used prefilled syringes (system B; n = 150) were microbiologically analyzed during single use of the syringes in one patient. Moreover, the contamination of a roller pump injector capable of multidosing several patients from a contrast agent container, without the need for prior filling, was determined after being used for an entire day (system C; n = 35 injections/day for 15 days). The hygienic background was guaranteed by taking imprints of the surfaces of devices and the palms of the hands of members of CT staff before the clinical investigation. The time required for assembly of the injection systems and for filling or refilling of each injector system was measured. The handling of the three systems also was subjectively ranked by the technicians. RESULTS: Injection systems A, B, and C remained microbiologically sterile and free of contamination throughout their use in clinical routine. The mean (± SD) time for injection system assembly and installation of syringes and filling did not differ significantly between injection systems A and B (system A, 2.5 ± 1.1 minutes; system B, 1.9 ± 1.3 minutes; p = 0.12), whereas the time for assembly of system C was significantly shorter (0.9 ± 0.6 minutes; p < 0.05 vs system A; p < 0.05 vs system B). In the subjective ranking of injector handling, systems B and C were preferred. CONCLUSION: Double-syringe injectors used with disposable or prefilled contrast agent syringes, as well as roller pump injectors, ensure hygienic conditions in clinical routine. However, time efficiency and handling are aspects that favor prefilled and roller pump systems.

Noncaseating granulomatous diseases in germ cell cancer patients-A single-center experience.

OBJECTIVES: In patients with testicular Germ Cell Tumors (GCT) noncaseating granulomatous diseases such as Sarcoid Like Lesions (SLL) or Sarcoidosis can mimic metastasis due to hilar or mediastinal lymphadenopathy. Due to the clinical and prognostic impact, exclusion of malignant diseases is mandatory. MATERIAL AND METHODS: Retrospectively, data from 636 GCT patients, who were seen in the course of tumor surveillance/follow-up were collected. Focus was put on the detection of tumor relapse vs. noncaseating granulomatous reactions. For the differential diagnosis of thoracic lymphadenopathy or pulmonary infiltrates either bronchoscopy (e.g., endobronchial ultrasound-guided transbronchial needle aspiration, endobronchial ultrasound-guided transbronchial needle aspiration) or thoracic surgery was performed. Both GCT patients with either tumor relapse or coexisting SLL were compared to GCT patients without SLL and tumor relapse. RESULTS: Twenty-nine patients suffered from suspected tumor relapse. Whereas thoracic relapses were suspected in 15 patients on chest computed tomography, thoracic relapse was confirmed in 5 cases by open surgery. In 2 cases open surgery yielded reactive lymphadenitis, and in 8 cases SLL was diagnosed either via EBUS-TBNA (n = 7) or thoracoscopic wedge resection plus lymphadenectomy (n = 1). With focus on overall survival, no relevant difference was found between all tested subgroups (P = 0.265; logrank test). CONCLUSIONS: In GCT patients, the coexistence of noncaseating granulomatous disease is common. Minimal invasive bronchoscopic techniques can serve for the cytopathologic exclusion of malignant thoracic manifestations. In our monocenter patient group the coexistence of SLL did not have any prognostic impact on overall survival.

The role of multislice computed tomography (MSCT) angiography in the diagnosis and therapy of non-occlusive mesenteric ischemia (NOMI): Could MSCT replace DSA in diagnosis?

OBJECTIVES: Evaluation of multislice-CT (MSCT) during diagnosis and therapeutic decision-making in patients with suspected non-occlusive mesenteric ischemia (NOMI). METHODS: Retrospective, institutional review board-approved study of 30 patients (20 men, 10 women, mean age 64.6±14.2 years, range 24-87 years) undergoing biphasic abdominal MSCT followed by digital subtraction angiography (DSA) due to suspected NOMI. MSCT and DSA were qualitatively and quantitatively evaluated independently by two radiologists with respect to the possible diagnosis of NOMI. MSCT analysis included quantitative measurements, qualitative evaluation of contrast enhancement and assessment of secondary findings (bowel wall thickening, hypo-enhancement, intestinal pneumatosis). MSCT diagnosis and secondary findings were compared against DSA diagnosis. RESULTS: NOMI was diagnosed in a total of n = 28 patients. No differences were found when comparing the R1-rated MSCT diagnosis (p = 0.09) to the "gold standard", while MSCT diagnosis was slightly inferior with R2 (p = 0.02). With R1, vessel-associated parameters revealed the best correlation, i.e. qualitative vessel width (r = -0.39;p = 0.03) and vessel contrast (r = 0.45;p = 0.01). Moderate correlations were found for quantitative vessel diameters in the middle segments (r = -0.48,p = 0.01), increasing to almost high correlations in the distal (r = -0.66;p<0.00001) superior mesenteric artery (SMA) segments. No significant correlation was apparent from secondary findings. CONCLUSIONS: MSCT is an appropriate non-invasive method for diagnosing NOMI and leads to adequate and immediate therapeutic stratification.