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Objective To determine the clinical value of contrast enhanced MRI in differentiating benign and malignant pancreatic endocrine tumors (PNETs).Methods MRI findings on 13 cases who were pathologically diagnosed as PNETs were retrospectively analyzed , including the tumor volume , border , MRI signal and adjacent organ involvement of Grade 1~3 tumors, and the sensitivity, specificity and accuracy of MRI for diagnosing PNETs were calculated .Results A total of 18 tumors were detected , including 12 benign (Grade 1) and 6 malignant (Grade 2~3) tumors.Eight Grade 1 tumors′(66.7%) maximal diameters were≤2 cm, while 100%(6 /6) Grade 2 ~3 tumors′maximal diameters were ≥2 cm.All of Grade 1 tumors (100%) had clear boundary , while 50%(2/4) Grade 2 and 100%(2/2) Grade 3 tumors had unclear boundary.Ten Grade 1 tumors (83.3%) had intratumoral homogeneous signal , while 100%(6/6) Grade 2~3 tumors had heterogeneous intratumoral signal .Two Grade 3tumors ( 100%) had organ infiltration and retroperitoneal lymph node metastasis .The sensitivity ,specificity and accuracy of MRI for differentiating benign and malignant PNETs were 833.%, 85.7%and 84.6%, respectively.Conclusi ons MRI had higher sensitivity, specificity and accuracy in differentiating benign and malignant PNETs , but it was still difficult to differentiate Grade 1 from Grade 2 tumors by MRI.Tumors size could not be considered to be a reliable indicator for differentiating benign and malignant PNETs .
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<p><b>OBJECTIVE</b>To evaluate the clinical feasibility of dual-source computed tomographic urography using dual-energy virtual non-enhanced CT.</p><p><b>METHODS</b>Totally 240 patients received dual-source CT, which included true non-enhanced CT (TNCT) , nephrographic phase scanning with dual-energy mode (100kVp/230mAs and Sn140kVp/178mAs) , and excretory phase scanning. A contrast bolus injection of 100 ml (370 mgI/ml) contrast agent was applied (4.5ml/s) , followed by 100ml normal saline (4.5ml/s) . Virtual non-enhanced CT (VNCT) image sets were reformatted from 'Liver VNC ' software. The mean CT number, noise, signal to noise ratio (SNR) , image quality, and radiation dose were compared between TNCT and VNCT image sets.</p><p><b>RESULTS</b>There was no significant difference in mean CT numbers of all organs (P>0.05) . However, VNCT images had significantly lower noise and higher SNR than TNCT images (both P<0.05) . Image quality of VNCT was lower than that of TNCT without significant difference (P>0.05) . Radiation dose of nephrographic phase with dual-energy mode was significantly higher than that of TNCT and excretory phase scanning (P<0.05) .</p><p><b>CONCLUSION</b>Dual-energy VNCT requires less radiation dose and therefore has a potential to replace TNCT in the dual-source CT urography.</p>
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Radiation Dosage , Radiography, Dual-Energy Scanned Projection , Methods , Reproducibility of Results , Sensitivity and Specificity , Signal-To-Noise Ratio , Tomography, X-Ray Computed , Methods , Urography , MethodsABSTRACT
<p><b>OBJECTIVE</b>To explore the feasibility of a dual-energy computed tomographic angiography (DECTA) protocol using test-bolus injection with reduction of contrast material (CM) dose in second generation dual-source CT system.</p><p><b>METHODS</b>Totally 57 consecutive patients underwent CT angiography scan covering the cervical and cerebral arteries. CT was performed with second generation dual-source CT system. The time to peak (T) using a test-bolus injection was calculated. The patients were divided into three groups (A, B, and C) with different CM doses (40, 45, and 50 ml) and different delay time points [ (T+1) , (T+1) , and (T+2) s] . All the patients were followed by a 48 ml saline flush. Arterial enhancements were quantified by measuring attenuation values of the aortic arch, bifurcation of common carotid artery, contralateral internal jugular vein of the CM injection, superior vein cava, proximal middle cerebral artery, basilar artery, and straight sinus on source images. Visualizations of intracranial artery and ipsilateral venous effect of the CM injection were rated on a four-point grading scale on CTA images for qualitative assessment.</p><p><b>RESULTS</b>Although the attenuation of internal jugular vein and straight sinus were significantly lower in group A than in groups B and C (P<0.05) , the attenuation of aortic arch, superior vein cava, common carotid artery, middle cerebral artery, and basilar artery vessels showed no significant differences among these three groups. The scores of the visualizations of intracranial artery and ipsilateral venous effect of the CM injection were also not significantly different among these three groups.</p><p><b>CONCLUSION</b>Based on the delay time calculated by a test-bolus injection, a reduced-dose contrast material may provide an equal degree of arterial attenuation and a lower attenuation of vein for dual-energy CTA covering the craniocervical region in second generation dual-source CT system.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Angiography , Methods , Contrast Media , Feasibility Studies , Head , Diagnostic Imaging , Neck , Diagnostic Imaging , Radiation Dosage , Tomography, X-Ray Computed , MethodsABSTRACT
Objective To evaluate the diagnostic value of physical examination,digital mammography and color Dopplor ultrasonography for breast masses.Methods The materials of clinic,digital mammography and color Dopplor ultrasonogrpahy(US)in 92 women(raged from 18～80 years old in age,with average of 49.8 years old)with breast masses confirmed by pathology were retrospectively analysed,including benign in 43 and malignant in 49.Digital mammographic findings including the location,shape,margins,calcifications and the lymph node of axillary of the breast lesions,and color Dopplor ultrasonographic findings including mainly the characteristics of lesions on two-dimensional sonography,the distribution of the internal and peripheral vessels of the lesions were observed,the physical examination mainly observed the skin and nipple,and the margins,texture and movement of the lesions.Results In diagnosing breast masses,the sensitivity,specificity,positive predictive value,negative predictive value and accuracy were 85.71%,79.07%,82.35%,82.93% and 82.61%,respectively with digital mammography,79.59%,83,72%,84.78%,78.26% and 81.52%,respectively with US,71.42%,76.74%,77.78%,70.21%,73.91%,respectively with physical examination,while were 91.84%,93.02%,93.75%,93.3% and 90.91%,respectively in combination with three methods,which were significantly higher than that of each single examination(P＜0.05),but there were no differences between each examination(P＞0.05).Conclusion It can improve the diagnosing accuracy of breast masses by suitable combination of three of digital mammography,color Dopplor ultrasonography and physical examination.