Purpose To evaluate ultrasonography in diagnosis of high recurrence risk gastrointestinal stromal tumors (GIST) by retrospective studying the ultrasound (US) imaging features of GITS. Materials and Methods US features of 72 GIST cases confirmed histopathologically were retrospectively studied. The tumor size, shape, boundary, echogenicity and blood flow of GITS were observed and compared with the results of histopathology. Results Of all the 72 tumors, 34 were originated in the stomach, 14 in the intestine, 2 in the colon, 8 in the rectum, 9 in the mesentery, 1 in the posterior peritoneum, 1 in the omentum and 3 huge masses of non definite origin. There were 7 cases with very low recurrence risk, 14 cases with low risk, 11 cases with intermediate risk and 40 cases with high risk. High recurrence risk group showed no statistical difference in heterogeneous hypoechoes and blood flow (P>0.05), but showed significantly higher rates in following US features:size larger than 5.0 cm, irregular shape, obscure boundary and cyst-solid echogenecity (P<0.001), which showed the sensitivity of 95.0% (32/40), 72.5% (29/40), 25.0% (10/40), and 55.0% (22/40), respectively; and the specificity of 59.4% (19/32), 81.3% (26/32), 90.6% (29/32), and 87.5% (28/32), respectively. Conclusion US can serve as a mean of screening GIST. The recurrence risk can be evaluated based on the tumor size, shape, boundary and echogenecity to guide clinical decisions and prognosis evaluation.

Purpose To detect the distribution of cerebral microbleeds (CMB) in patients with hypertension and evaluate its related risk factors in order to reduce long-term risk of cerebral hemorrhage in large areas. Materials and Methods A consecutive 110 patients of hypertension and 50 patients of non-hypertension in the departments of cardiovascular medicine and neurology were enrolled. All the patients underwent T2 star weighted angiography (SWAN) sequence scan of head. The location and quantity of CMB and other related information of patients were recorded. The distribution of CMB in patients with hypertension and correlation between CMB and age, sex, level of hypertension, duration of time, hemoglobin, platelets, smoking, diabetes, hyperlipidemia were also analyzed. Results A total of 472 CMB were detected in the hypertension group, of which 212 CMB (44.9%) were found in deep brain, 149 (31.6%) were in cortical and subcortical region, 111 (23.5%) under the tentorium. The highest distribution of CMB was in thalamus (98, 20.8%), followed by basal ganglia (78, 16.5%), temporal lobe (64, 13.6%) and brainstem (62, 13.1%). The univariate analysis showed that CMB group had significantly higher rate of hypertension and diabetes than that without CMB and the average age in CMB group was also higher (P<0.05). The results of multivariate analysis showed that age and hypertension were independent risk factors for CMB. In hypertension group, there was statistically significant difference in the incidence of CMB between patients aged 45 and older and those aged under 45 (P<0.05);the differences were significant between the patients with hypertension duration time less than 5 years, those with hypertension duration time 5 to 10 years and those over 10 years (P<0.05);the differences also existed between the patients with hypertension at class I and those patients with hypertension at class II and III (P<0.05). The quantity of CMB in patients with hypertension was correlated with duration time (P<0.05), but not correlated with age and the severity of hypertension (P>0.05). Conclusion Hypertension and age are independent risk factors for CMB. Patients aged 45 and older, with more than 5 years duration of hypertension, or with hypertension at class II and III, should be paid more attention in clinic. If necessary, magnetic resonance examination is suggested to be used, in order to reduce long-term risk of cerebral hemorrhage.

Purpose Central nervous system (CNS) hemangiopericytoma (HPC) is rare in clinic and prone to misdiagnosis. This paper aims to improve the diagnostic accuracy of CNS HPC by analyzing the MRI and CT features. Materials and Methods CT and MRI appearances and pathologic features of 14 cases with surgery and pathology proved CNS HPC were analyzed retrospectively. Results There were intracranial and intraspinal lesions in 12 and 2 cases respectively. 5 cases were lobular, 4 cases irregular, and 5 cases were round or oval in shapes. On CT scan, 2 intracranial lesions showed slight hyperdensity and were avidly enhanced following contrast injection. On T1WI, 11 cases showed isointensity compared with brain white matter;on T2WI, 10 cases showed isointensity compared with brain gray matter. Marked heterogeneous enhancement was shown in 7 cases. Necrosis and cystic changes were seen in 6 cases. Flow-void sign was seen in 9 cases;9 cases were attached to meninges through narrow base. Dural tail sign was observed in 4 cases. Bone erosion was seen in 4 cases. In 5 cases with DWI scan, isointensity was shown in 4 cases and slight hyperintensity in 1 case. The density and signals in 2 cervical spine lesions were uniform with homogenous enhancement;expansive bone swelling in 1 case. Conclusion CNS HPC shows hyperdensity on CT. They present equal signal compared with white matter on T1WI and equal signal compared with grey matter on T2WI, with some void signal of vessel, and isointense on diffusion weighted images. Tumor invades adjacent skull with rare dural tail sign.

Purpose To evaluate the left ventricular regional diastolic function in coronary heart disease (CHD) patients without regional wall motion abnormality by real-time three-dimensional speckle tracking imaging (RT3D-STI) to investigate the value of RT3D-STI in the diagnosis of early CHD. Materials and Methods 140 CHD patients with 420 coronary artery main branches were enrolled and divided into 4 groups according to the results of coronary angiography (CAG): normal group (101 coronary artery branches without stenosis), mild stenosis group (112 coronary artery branches with stenosis<50%), moderate stenosis group (95 coronary artery branches with stenosis 50%-75%) and sever stenosis group (112 coronary artery branches with stenosis>75%). Three dimensional full volume images were collected through the chest, and the corresponding strain imaging diastolic index (SI-DI) of each direction was calculated, their value for the diagnosis of coronary artery disease was analyzed. Results The longitudinal, area and radial SI-DI of mild coronary artery stenosis group were lower than those of normal group (P<0.05);the longitudinal, area, radial and circumferential SI-DI of moderate coronary artery stenosis group were lower than normal group (P<0.05) and the area, longitudinal and circumferential SI-DI were lower than those of the mild stenosis group (P<0.05);the longitudinal, area, radial and circumferential SI-DI were all lower than those of normal and mild stenosis group (P<0.05), and the area, longitudinal and radial SI-DI were all lower than the moderate stenosis group (P<0.05). ROC curve showed that the sensitivity of longitudinal SI-DI (84.0%) was highest, while the specificity of area SI-DI (78.9%) was the highest. Conclusion RT3D-STI has important significance for early detection and diagnosis of CHD, regional diastolic function decrease of the coronary artery supply area occurs earlier than systolic function reduction, and diastolic function is more sensitive for myocardial ischemia, as a result, SI-DI is able to reflect the stenosis degree of coronary artery in a certain extent.

Purpose Median arcuate ligament (MAL) compression is the most common reason for celiac artery stenosis or occlusion, celiac artery compression of asymptomatic MAL is often misdiagnosed. This study aims to evaluate the multi-slice spiral CT manifestations of the celiac artery compression of median arcuate ligament. Materials and Methods CT features of 26 patients with celiac artery compression of median arcuate ligament were retrospectively studied. Eleven cases were symptomatic and fifteen cases were asymptomatic. Results In 14 cases (53.8%), the location of compression was at the level of superior 1/3 of the L1 vertebral body. There was statistic difference in location of the origin of compression between the celiac artery narrowing group and the non-narrowing group (P<0.05). CT manifestations included: narrowing of the celiac artery were observed in 26 patients on sagittal reformatted images with hollow on the anterior wall; a characteristic hooked appearance was observed. Narrowed celiac artery on the transverse images was seen in 21 patients, and a soft-tissue band extending across the anterior aspect of artery in 12 of them. Poststenotic dilatation was revealed in 20 patients. Collateral circulation was seen in 8 patients. Conclusion Multi-slice spiral CT can be helpful in demonstrating the location of celiac artery compression of median arcuate ligament and tell the characteristic imaging features.

Purpose To analyze the correlation of pulmonary artery obstruction index (PAOI) and the cardiovascular parameters in patients with massive pulmonary embolism (MPE), and to explore the CT pulmonary angiography (CTPA) significant in radiological massive pulmonary embolism. Materials and Methods Sixty-two patients with massive pulmonary embolism confirmed by CTPA were divided into two groups according to the severity with 17 cases in high-risk group and 45 cases in non-risk group. The correlation between pulmonary artery obstruction index and cardiovascular parameters of all subjects was analyzed. Parameters in the two groups were compared including PAOI, ratio of main pulmonary artery diameter (MPAd) to the ascending main artery diameter (AAd) named rPA, and ratio of right ventricular diameter (RVd) to the left ventricular diameter (LVd) named RVd/LVd. Results Pulmonary artery obstruction index had positive correlation with the cardiovascular parameters (r=0.504, 0.543, 0.629 and 0.657, P<0.05), but negative correlation with LVd (r=-0.500, P<0.05). PAOI, MPAd, rPA, RVd/LVd and RVd were higher in the high-risk group than those in the non-high-risk group (P<0.05). LVd was lower in the high-risk group than that in the non-high-risk group (P<0.05). Conclusion CTPA can not only effectively diagnose pulmonary embolism but also assess the severity of the radiologic massive pulmonary embolism, which contributes to the clinical prognosis and treatment options.

Purpose To explore the feasibility of optimizing monochromatic images in reducing iodinated contrast dose in CT pulmonary angiography (CTPA). Materials and Methods Sixty-eight patients undergoing CTPA were randomly divided into two groups, with half in research group and half in conventional group to evaluate image quality. Research group underwent spectral CT imaging with the injection of 30 ml Omnipaque (300 mgI/ml) and optimal monochromatic images were postprocessed using the software of GSI viewer. Conventional group underwent conventional CTPA with the injection of 80 ml Ultravist (370 mgI/ml). The CT values were measured respectively in the main pulmonary artery, left pulmonary trunk, right pulmonary trunk, left lobe artery and right lobe artery. The contrast noise ratio (CNR) in two groups were calculated, and image quality were subjectively assessed. Results The total iodine intake in research group (9000 mg) was significantly lower than that of conventional group (29 600 mg). CNR in the main pulmonary artery, left pulmonary trunk, right pulmonary trunk, left lobe artery and right lobe artery in research group was significantly higher than that of conventional group (t=2.07-2.71, P<0.05). Subjective image quality scores in research group were also higher than that of conventional group but had no statistical difference (Z=-0.944, P>0.05), while there was a good agreement between the two readers (Kappa=0.8, P<0.05). Conclusion It is possible to reduce iodinated contrast dose using spectral CT imaging and improve the image quality of CTPA.

PurposeWith the extensive use of percutaneous radiofrequency ablation (RFA) for the treatment of hepatic carcinoma (HC), the study of MRI findings and its clinical signiifcance after RFA of HC have important value and can improve the complete ablation rate.Materials and MethodsA retrospective analysis of post-procedure MRI ifndings of 79 patients (114 lesions) with HC were performed, the size of the lesion, the signal changes and enhancement condition were observed at the ifrst, fourth and seventh month after RFA; the two different ifndings of high signal ring on MRI T1WI and local recurrence rate were analyzed.ResultsOne month after RFA, peripheral region of RFA lesion showed high signal on T1WI, and slightly lower signal on T2WI, the size of lesions was slightly larger than pre-procedure, enhancement scan showed the thin homogeneous ring enhanced around the non-enhanced lesions; 4 months later, the size of lesions were relative stable and the periphery enhancement was weaken; 7 months later, the size of lesions were reduced and showed no enhancement. For recurrence lesions, the high signal ring was incomplete on TIWI, the incomplete area showed nodular enhancement on the arterial phase, and most of nodule showed slightly lower signal on the delay phase demonstrated a feature of quick wash-in and wash-out; 7 months after RFA, recurrence rate was 6.12% in patients with complete high signal ring and 43.75% in patients with incomplete high signal ring, the difference was statistically significant (P<0.05). The total survival rate and accumulated survival rate of the patients with complete high signal ring on T1WI were higher than the patients with incomplete ring, the difference was statistically signiifcant (P<0.05).ConclusionThere are characteristic ifndings of MRI examination of liver cancer after percutaneous RFA, observation of the integrity of high signal ring on T1WI image and ifnding of dynamic enhancement scan can early evaluate efifcacy of RFA guide the selection of treatment plan.

PurposeConventional gastric CT provides poor contrast for gastric cancer lesions, the purpose of this study is to investigate the application value of dual energy CT image fusion technology in the improvement of lesion contrast in gastric cancer.Materials and Methods Abdominal dual energy contrast-enhanced CT images of 30 gastric cancer patients were retrospectively analyzed, dual-energy images were reconstructed with different linear and nonlinear fusion settings, contrast between lesions and normal gastric wall, lesion contrast to noise ratio (CNR) were compared among 100 kVp, 140 kVp and different fusion groups, and image quality was evaluated subjectively.Results There were statistically significant differences among the gastric cancer contrast and CNR of 100 kVp, 140 kVp and three linear blending images (F=29.6 and 26.1,P<0.001), with M=0.7 linear fusion group showing the highest CNR. The gastric cancer contrast and CNR was signiifcantly higher with a bandwidth (BW) of 0 HU when compared among the three groups of nonlinear blending images (F=268.5 and 49.5,P<0.001). Moreover, the nonlinear group with a width of 0 HU had a 36% and 47% increase in lesion contrast and CNR over that of a linear blending image. In the subjective evaluation of images, the BW=0 HU nonlinear fusion image was most frequently estimated as the most preferred images for lesion observation of gastric cancer.Conclusion Nonlinear blending with a BW of 0 HU improves display of gastric cancer, and has the potential clinical value to increase the accuracy of staging.

PurposeRecurrence limits the survival of postoperative hepatocellular carcinoma (HCC) patients. The purpose of this study is to investigate the value of ultrasound (US), CT and MRI follow-up in alpha fetoprotein (AFP) negative HCC patients.Materials and MethodsThe follow-up data of 31 pathology-confirmed, AFP negative HCC patients were analyzed retrospectively. All patients underwent US, CT and MRI. Features including tumor size, morphology, echogenicity and enhancement pattern were analyzed. The recurrent lesion detection rates of all three diagnostic modalities were compared.ResultsThere were 55 recurrent lesions. On CT and MRI, these lesions were round or ovoid in shape with long axis of 0.7-3.4 (1.7±1.1) cm. There were 16 solitary lesions and multifocal lesions in 15 cases. US showed widely distributed blood vessels within the lesions and heterogeneous flow rate. CT and MRI demonstrated significant enhancement in the arterial phase with wash out in portal phase and delayed phase. The detection rate were 60.0% (33/55), 83.6% (46/55), 89.1% (49/55) for US, CT and MRI, respectively (χ2=15.120,P<0.01). Detection rate of MRI (80.0%, 16/20) was signiifcantly higher than that of CT (65.0%, 13/20) and US (40.0%, 8/20) for lesions with long axis diameter of 0.7-1.0 cm (χ2=6.910,P<0.05). For lesions between 1.0-2.0 cm, MRI, CT and US detection rate were 91.7% (22/24), 91.7% (22/24) and 66.7% (16/24), respectively (χ2=6.792,P<0.05). ConclusionImaging follow up can detect AFP negative HCC recurrence. MRI has unique advantage in lesions <2 cm.