Influence of lesion ratio on diagnostic performance of in-phase/opposed-phase imaging and apparent diffusion coefficient for differentiating acute benign vertebral fractures and metastases.

BACKGROUND: The usefulness of in-phase/opposed-phase imaging and diffusion weighted imaging (DWI) in differentiating benign and neoplastic vertebral fractures has been described. In this study, we aimed to evaluate the influence of the severity of vertebral damage on the diagnostic performance of these two technologies. METHODS: Totally 59 patients with 68 acute benign vertebral fractures and 43 patients with 79 vertebral metastases were included in this study. The MR protocol included DWIs and sagittal in-phase/opposed-phase gradient recalled sequence. The severity of vertebral damage was expressed by lesion ratio (LR, the ratio of lesion area to vertebral area on the slices of largest abnormal signal area in the T1-weighted sequence). Quantitative (signal intensity ratio (SIR) defined as signal intensity (SI) on opposed-phase gradient recalled echo (GRE) images divided by SI on in-phase; apparent diffusion coefficient (ADC) value derived from DWI analysis was performed, the relationships between LR and the measurements of these two technologies were analyzed using linear regression. The covariate-specific receiver operating characteristic (ROC) curves were also fitted to evaluate the influence of LR on the diagnostic performance of ADC and SIR. RESULTS: The difference in both SIR and ADC for vertebral metastasis and acute benign vertebral fractures was significant (P < 0.001). A positive correlation between the LR and the SIR was found in benign fractures (P < 0.05). The severity of vertebral damage had a significant influence on the AUC (area under ROC curve) for SIR (P < 0.05) but ADC (P > 0.05). More severe cases were associated with increased AUC for SIR. CONCLUSIONS: LR is capable of affecting the diagnostic performances of chemical shift imaging. Thus, when applying these tests to make diagnoses on vertebral fractures, the severity of the vertebral damage should be taken into account. The covariate-specific ROC model is recommended because it substantially improves the ability to avoid bias when evaluating tests.

[Role of 16 slices spiral CT angiography with 3-dimensional CT and CT virtual endoscopy in detecting blood supply of lung carcinoma].

BACKGROUND & OBJECTIVE: Angiography, a common method in evaluating blood supply of lung carcinoma, is invasive and complicated, with low success rate for bronchial artery, and could not assure to show all supply blood vessels at a time. This study was to explore clinical value of 16 slices spiral CT angiography with 3-dimensional CT (3DCT) and CT virtual endoscopy (CTVE) in diagnosing and evaluating supply blood vessels and blood supply of lung carcinoma, so as to find a non-invasive, safe, simple and effective method in diagnosing blood supply of lung carcinoma. METHODS: A total of 72 patients with pathologically proved lung carcinoma underwent 16 slices spiral CT angiography with 3DCT. Volume rendering (VR), maximum intensity projection (MIP), and surface shaded display (SSD) of supply blood vessels of lung carcinoma were used as 3DCT models. CTVE of bronchial artery was performed in 25 patients. Color VR of tumor lesion was performed in all patients. RESULTS: Supply blood vessels were showed in 68 patients, 59 of them showed only bronchial artery, 5 showed intercostals arteries, and 4 showed mixed types, including bronchial artery, intercostals arteries, or branch arteries of subclavian artery. The bronchial artery entered into enlarged mediastinal lymph nodes in 4 patients. CTVE well displayed the orifice and lumen of bronchial arteries in the 25 patients. The extent of red color of tumor lesion on VR color image were divided into 4 types: no color (n=11), light red (n=17), moderate red (n=32), and heavy red (n=12); the added CT values of tumor lesion after enhanced CT were (6.16+/-2.23) Hu, (15.71+/-3.13) Hu, (25.47+/-2.71) Hu, and (44.31+/-19.68) Hu, respectively. The corresponding rate between enhanced type and distributive type of red color on color VR was 86.1%. CONCLUSIONS: The 16 slices spiral CT angiography with 3DCT and CTVE could show clearly supply blood vessels and blood supply of lung carcinoma. It is a non-invasive, simple and effective method in evaluating and diagnosing blood supply of lung carcinoma.

[CT findings of ischemic infarction in relation to neuronal damage in rabbits].

OBJECTIVE: To explore the early changes in CT findings of ischemic infarction in relation to neuronal damage in rabbits. METHODS: Thirty-two rabbits were divided into control group and experiment groups and scanned with CT 2, 4, 8, 12, 18, 24, and 36 h after ischemic cerebral infarction induced by PVA embolization of the middle cerebral artery (MCA), respectively. The brain specimen were stained with HE, Nissle and TUNEL techniques for pathological examination. RESULTS: In stage I (2-8 h after MCA occlusion) by CT staging, the neurons exhibited ischemic change followed by cell edema. A small number of TUNEL-positive cells were found in the basal ganglia and cortex. In stage II (12-18 h after MCA occlusion), neuronal swelling and lysis were observed with greater number of TUNEL-positive neurons in the basal ganglia and cortex. In stage III ( 24-36 h after MCA obstruction), cerebral edema became obvious and ischemic cores were distinct, with numerous necrotic neurons seen and destruction of the cell structure. Numerous TUNEL-positive cells were seen in the ischemic penumbra and cortex. CONCLUSION: The damaged neurons after ischemic cerebral infarction showed varied morphology including cell edema, apoptosis, necrosis, and necrosis-apoptosis continuum. CT manifestations are strongly associated with the progression of ischemia and the pathological changes.

[The value of three-phase pulmonary helical CT in diagnosing peripheral pulmonary cancer (diameter

OBJECTIVE: To evaluate the value of three-phase pulmonary helical CT in diagnosing peripheral pulmonary cancer (diameter

[Helical dual-phase CT scan in evaluating blood supply of primary heptocellular carcinoma after transcatheter hepatic artery chemoembolization with lipiodol].

OBJECTIVE: To evaluate the blood supply of low density viable area of primary heptocellular carcinoma after transcatheter hepatic artery chemoembolization using lipiodol (LP-TACE), by helical dual-phase CT scanning and three dimensional CT (3DCT). METHODS: Thirty-four patients with primary heptocellular carcinoma after LP-TACE were examined by hepatic helical dual-phase CT. 3DCT model of the maximum intensity projection (MIP), surface shaded display (SSD) reconstruction of the hepatic artery and portal vein were simultaneously done in 5 cases. RESULTS: Viable tumor areas of 34 cases of primary heptocellular carcinoma after LP-TACE were divided into four types: peripheral, lateral, central and diffused types. Enhanced tumor vessel or tissue in viable tumor area was found during hepatic dual-phase in 17 cases, during hepatic artery-phase only in 8 and hepatic portal vein-phase only in 3. The viable tumor areas were found to have blood supply from the hepatic vein in 2 cases. The viable tumor area unenhanced during hepatic dual-phase was found in 6 cases. In 5 cases, the relation between the viable tumor area and branches of hepatic artery and portal vein was showed by MIP and SSD of hepatic artery and portal vein. CONCLUSION: Hepatic helical dual-phase CT scan with 3DCT is effective in evaluating the blood supply of viable tumor areas and the therapeutic effect of primary heptocellular carcinoma after LP-TACE.