High-pitch low-dose abdominopelvic CT with tin-filtration technique for detecting urinary stones.

OBJECTIVES: To evaluate urinary stone detection, radiation exposure, image quality, breathing-motion artifacts, and scanning time with high-pitch tin filter-based abdominopelvic CT. METHODS: Sixty-three consecutive patients with urolithiasis underwent non-enhanced abdominopelvic CT with both regular (120 kV, pitch 0.6) and low-dose (Sn150kV, pitch 3.0) protocols on a third-generation dual-source CT. Stone characteristics, image noise (SD), signal-to-noise ratio (SNR), subjective image quality on a 5-point likert scale breathing-motion artifacts, and scanning time were evaluated. Volume CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED) were compared. RESULTS: A total of 157 urinary stones were detected by regular protocol; 154 were correctly identified by low-dose protocol with an overall detection rate of 98.1%. No significant differences were observed in SD, SNR, or subjective image quality between two protocols (P > 0.05). Compared to regular protocol, CTDIvol and ED were 56.6% (7.19 vs. 3.12 mGy, P < 0.001) and 55.6% (5.25 vs. 2.33 mSv, P < 0.001) lower; scanning time was 89.5% (7.9 vs. 0.83, P < 0.001) shorter; and breathing-motion artifacts were fewer (8 vs. 0 patients) with low-dose protocol. CONCLUSIONS: High-pitch abdominopelvic CT with Sn150kV substantially reduced radiation exposure and scanning time, while maintained stone detection and image quality and prevented breathing-motion artifacts.

Impact of target area selection in 125 Iodine seed brachytherapy on locoregional recurrence in patients with non-small cell lung cancer.

BACKGROUND: Computed tomography (CT)-guided percutaneous implantation of 125 Iodine radioactive seeds requires the precise arrangement of seeds by tumor shape. We tested whether selecting target areas, including subclinical areas around tumors, can influence locoregional recurrence in patients with non-small cell lung cancer (NSCLC). METHOD: We divided 82 patients with NSCLC into two groups. Target areas in group 1 (n = 40) were defined along tumor margins based on lung-window CT. Target areas in group 2 (n = 42) were extended by 0.5 cm in all dimensions outside tumor margins. Preoperative plans for both groups were based on a treatment plan system, which guided 125 I seed implantation. Six months later, patients underwent chest CT to evaluate treatment efficacy (per Response Evaluation Criteria in Solid Tumors version 1). We compared locoregional recurrences between the groups after a year of follow-up. We then used the treatment plan system to extend target areas for group 1 patients by 0.5 cm (defined as group 3 data) and compared these hypothetical group 3 planned seeds with the actual seed numbers used in group 1 patients. RESULTS: All patients successfully underwent implantation; none died during the follow-up period. Recurrence was significantly lower in group 2 than in group 1 ( P < 0.05). Group 1 patients and group 3 data significantly differed in seed numbers ( P < 0.01). CONCLUSION: Our results imply that extending the implantation area for 125 I seeds can decrease recurrence risk by eradicating cancerous lymph-duct blockades within the extended areas.

[Value of enhanced computed tomography in the diagnosis of adrenal hemangioma].

OBJECTIVE: To summarize the computed tomography (CT) findings of adrenal hemangioma. METHOD: The CT findings of 9 patients with pathologically proved adrenal hemangioma from June 2008 to March 2011 were retrospectively reviewed. RESULTS: All the tumors were located unilaterally, with 4 in the left and 5 in the right. The tumors were 1.5-8.4 cm in size with complete capsule and well-defined contour. Among these nine tumors, six were round or ovoid, while the other three had irregular shapes. Plain scan showed mixed density in 8 and cystic change in 1. After contrast enhancement, six tumors manifested with inhomogeneous enhancement and the other three without enhancement. For three cases who underwent multi-phase enhanced CT scans, irregular enhancement at the periphery of the masses were showed in artery phase, and centripetal filling with contrast medium to the center of masses were showed in the portal and delayed phases. CONCLUSIONS: Hemangioma is a rare benign tumor of the adrenal gland. CT findings are diverse, and the preoperative misdiagnosing rate can be high. Multi-phase enhanced CT scan may show characteristic features of adrenal hemangioma and help achieve correct preoperative diagnosis.

[Dual-energy computed tomographic angiography of head and neck arteries with different contrast material doses in second generation dual-source computed tomography system].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Radiological features of dual-energy CT lung perfusion imaging in patients with acute pulmonary embolism: comparison with CT pulmonary angiography].

OBJECTIVE: To explore the relationship of the perfusion defects in the dual-energy CT lung perfusion image and the filling defects in the CT pulmonary angiography (CTPA) in patients with acute pulmonary embolism. METHODS: The clinical data of 22 patients with acute pulmonary embolism were retrospectively analyzed. All of them underwent contrast CT scan in two phases using dual-energy CT: the first is pulmonary artery phase, and the second was performed immediately after the first phase using dual-energy scan covered the whole lung. Perfusion defects in the lung perfusion images were compared with the filling defects in the CTPA. RESULTS: Complete filling defects of segmental and subsegmental pulmonary arteries mostly showed correspondence perfusion defects in the CT perfusion map, accounting for 83% and 62% respectively. However, when there were partial or central filling defects, most of them were partial perfusion defects or normal in the CT perfusion map. Three segmental perfusion defects were depicted without the visualization of endoluminal thrombi within the corresponding arteries. CONCLUSIONS: The perfusion defects in the CT lung perfusion image are not completely corresponding to the filling defects in the CTPA. The combination of CTPA and CT lung perfusion map will offer more information for the acute pulmonary embolism.

Application of computed tomographic colonography in diagnosis of colonic polyps.

OBJECTIVE: To assess the clinical values of computed tomographic colonography (CTC) in diagnosis of colonic polyps. METHODS: Forty-two patients who were clinically suspicious of colonic polyps or underwent colonic polyps screening received examinations with both CTC and conventional colonoscopy. Sixteen- or 64-slice spiral computed tomography and professional imaging processing techniques were used for evaluation. Per-polyp and per-patient results were analyzed. Those by per-polyp were subsequently divided into > or = 10 mm group, 5-10 mm group, and < or =5 mm group. Sensitivity, positive predictive value (PPV), specificity, negative predictive value (NPV), and accuracy were calculated using statistical method for diagnostic studies, with conventional colonoscopy as a gold standard. RESULTS: Ninety and 61 polyps were found by CTC and conventional colonoscopy, respectively. The per-polyp sensitivity/PPV were 80.3%/55.6% in total, and 100%/92.9%, 93.8%/65.2%, and 68.8%/ 41.5% in the > or = 10 mm group, 5-10 mm group, and < or =5 mm group, respectively. The per-patient sensitivity, PPV, specificity, NPV, and accuracy were 97.1%, 89.5%, 42.9%, 75.0%, and 88.1%, respectively. CONCLUSION: CTC can clearly reveal the morphology of colonic polyps and be used as a routine monitoring method for the clinical diagnosis of polyps.

[Application of multi-slice spiral CT in the diagnosis of pulmonary hypertension].

OBJECTIVE: To evaluate the utility of multi-slice spiral CT in the diagnosis of pulmonary hypertension. METHODS: The clinical and multi-slice spiral CT data of 22 patients with pulmonary hypertension were retrospectively analyzed. The diagnoses included chronic thromboembolic pulmonary hypertension (CTEPH) (n = 9), primary pulmonary hypertension (PPH) (n = 7), connective tissue diseases (n = 2), portal-pulmonary hypertension (n = 2), eosinophilia-myalgia syndrome (n = 1), and fibrosing mediastinitis (n = 1). Lung parenchyma, such as ground-glass opacity, mosaic attenuation and septal thickness, mediastinum, pulmonary vascular, right ventricular enlargement and interventricular septum displacement were evaluated on CT. RESULTS: CT pulmonary angiography (CTPA) accurately diagnosed 95% of pulmonary hypertension and the signs of right ventricular dysfunction. Pulmonary embolism was found in 9 patients. The incidence of mosaic attenuation was significantly higher in CTECH than in PPH (P = 0.034). CONCLUSION: CTPA can accurately diagnose pulmonary hypertension and thereby provide useful information for the etiological diagnosis.

[Comparison of radiography and magnetic resonance imaging in detecting arthropathies in patients with hemophilia].

OBJECTIVE: To compare magnetic resonance imaging (MRI) and radiography in detecting arthropathies in patients with hemophilia. METHODS: Of 41 symptomatic joint images in the 14 patients with hemophilia, each joint was examined with both radiography and MRI within the same day. Imaging findings with both two modes were compared. RESULTS: Soft tissue swelling or joint effusion was observed in 33 joints by radiographs and in 34 joints by MRI. Joint erosions were demonstrated in 34 joints by MRI and in 20 joints by radiographs. Joint cysts were shown in 21 joints by MRI and in 9 joints by radiographs. Significant differences in the detection of erosion and cyst were found between radiography and MRI (P < 0. 05). MRI showed improvement for detecting more foci of both erosion and cyst than radiography. Bone marrow edema in 14 joints, hemorrhage in 34 joints, and synovial hypertrophy in 27 joints were revealed only by MRI. CONCLUSION: MRI is superior to conventional radiography in detecting the abnormal changes, and should be considered as the imaging mode of choice in evaluating hemophilic arthropathies.

[Clinical, pathological and radiological characters of appendiceal mucocele].

OBJECTIVE: To improve capability of appendiceal mucocele diagnosis via analyzes its clinical, pathological basis and radiological results. METHODS: Summarize 18 cases with pathological diagnosed appendiceal mucocele in PUMC Hospital since January 1985 till september 2004, including 4 males and 14 females (1:3.5), age ranged from 31 to 78 yrs old (average 59.8 years old). Eleven cases underwent barium enema, in which 9 cases received abdominal CT scanning and 1 case received CT virtual colonography. RESULTS: (1) CLINICAL RESULTS: 8 cases (44.4%) had right lower abdominal pain, 12 cases (66.7%) had palpable abdominal mass. (2) Radiological results: barium enema showed extrinsic oppressed filling defect at the end of cecum without destruction of mucosa; CT scanning showed right lower abdominal cystic mass, 75% with cystic wall calcification, massive septal mucous ascites was seen in one case with pseudomyxoma peritonei; CT virtual colonography showed clearly the extra cavity and intracavity changes at cecum. (3) Pathological results: simple mucocele (4 cases, 22.2%), mucous cystadenoma (12 cases, 66.7%) and mucous cystadenocarcinoma (2 cases, 11.1%) CONCLUSION: There are four pathological types in appendiceal mucocele. Radiological characters of appendiceal mucocele have distinct specificities while its clinical ones not. Radiological procedures are vital for correct clinical diagnosis.

[Techniques and clinical applications of 16 multislice helical CT in colonic diseases].

OBJECTIVE: To evaluate the techniques and clinical applications of 16 multislice helical CT in colonic lesions. METHODS: Eighty-one patients including 54 colorectal carcinomas, 5 adenomas, 1 non-Hodgkin's lymphoma, 6 inflammatory bowel diseases, and other 15 cases underwent volume scanning using 16 multislice helical CT. Four types of reconstruction included multiple planar reconstruction, shaded surface display, raysum, and CT virtual colonoscopy. RESULTS: Complete colon could be shown in all patients. The lesions' morphology, number, size, location, intestinal cavity, pericolonic changes, and other abdominal organs were satisfactorily shown by CT. CONCLUSIONS: Sixteen multislice helical CT colonography is a valuable imaging technique for detecting colonic diseases. It is effective in diagnosis and treatment planning. It can display the portions of colon that is inaccessible at colonoscopy.

[Thoracic high resolution CT findings of 100 SARS patients in convalescent period].

OBJECTIVE: To study thoracic high resolution CT findings of severe acute respiratory syndrome (SARS) patients in convalescent period and the relationship between the features with laboratory and pulmonary function results. METHODS: All the 100 SARS patients who had been discharged from hospital for about 2 months underwent thoracic high resolution CT examinations. Among them, 65 also had laboratory results and 91 underwent examinations of pulmonary function. RESULTS: Forty-nine SARS patients (49.0%, 49/100) in convalescent period still had abnormal findings in CT examination. And ground-glass opacification (95.9%, 47/49) and reticular opacification (59.2%, 29/49) were common. There was no significant difference in the level of lymphocytes and CD4 cells among groups divided according to severity of CT findings (P > 0.01). Diffusing capacity for carbon monoxide (DLco%) of level 2 and 3 were statistically lower than that of level 0 (P < 0.01). CONCLUSIONS: The features of CT findings of SARS patients in convalescent period are not the same as those of patients in period of apparent manifestation. The high resolution CT can reflect pulmonary diffusing function to some degree.