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Objective To investigate the feasibility of iterative model reconstruction (IMR) combined with low tube voltage and low iodine intaken of contrast media in head and neck CT angiography (CTA). Methods Eighty patients with clinical suspicion of head and neck vascular disease underwent head and neck CTA were enrolled in this prospective study. According to random number table, patients were randomly divided into two groups. Group A (n=40) was scanned according to the protocol of 120 kV, 50 ml iopromide (370 mg/ml) and filtered back projection (FBP) reconstruction, and group B (n=40) was scanned with 80 kV, 30 ml iohexol (300 mg/ml) and IMR, while the other parameters kept consistent. Mann-Whitney U test was used to compare the enhanced CT value of arteries, image noise, signal noise ratio (SNR), contrast noise ratio (CNR), the score of image quality, effective radiation dose (ED) and iodine intaken of contrast media between two groups. Results The CT value at the origin level of common carotid artery were (316.9 ± 53.0) and (433.4 ± 101.8)HU in group A and B, image noise were (28.1 ± 6.8)and (12.1 ± 2.6)HU ,SNR were (11.9 ± 3.2) and (37.7 ± 13.3) ,and CNR were (10.2 ± 2.9) and (32.6 ± 13.3), respectively. There were showed significant differences in CT value, image noise, SNR and CNR between two groups (Z=-5.490,-7.592,-7.698,-7.660, P<0.05). The CT value at the origin level of internal carotid artery were (359.5 ± 54.3) and (443.5 ± 120.1) HU in group A and B, image noise were (18.8±6.2) and (6.8±1.7) HU ,SNR were 21.5±8.7 and 69.7±27.4 ,and CNR were 18.0±7.3 and 62.7± 26.4, respectively. The significant differences were acquired in CT value, image noise, SNR and CNR between two groups (Z=-3.022,-7.376,-7.496,-7.515, P<0.05). The CT value at M1 segment level of middle cerebral artery were (321.1±47.3) and (401.6±104.0) HU in group A and B, image noise were (32.3± 17.2) and (11.2 ± 2.7) HU,SNR were 12.4 ± 5.6 and 39.3 ± 18.4,and CNR were 10.7 ± 4.7 and 36.4 ± 17.7, respectively. There also showed significant differences in CT value, image noise, SNR and CNR between two groups (Z=-3.527,-7.487,-7.482,-7.535, P<0.05). The score of image quality of group A and B were 3.9 ± 0.7 and 4.5±0.6, which also showed significant difference between two two groups (Z=-3.517, P<0.05). The ED were (2.78 ± 0.13) and (0.84 ± 0.04) mSv for group A and B, which also showed significant difference between the two groups (Z=-7.706, P<0.05). The iodine intaken of contrast media were 1.85 g and 0.90 g in group A and B. Conclusion IMR combined with low tube voltage and low iodine intaken of contrast media can not only decrease effective radiation dose and iodine intaken of contrast media significantly, but also improve the imaging quality in head and neck CTA examination.
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Objective To investigate the difference of apparent diffusion coefficients (ADCs) changes in three major salivary glands after gustatory stimulation using two different stimuli. Methods Thirty healthy volunteers were examined with a 1.5 T MR unit. A diffusion-weighted MR imaging (MR DWI) sequence was performed once at rest and continuously repeated 13 times after gustatory stimulation using a commercially available lemon juice and vitamin C tablets in the same volunteer by using self-controlled method. The subsequence of two stimuli was random. In addition, the salivary flow rates at rest and after stimulation were measured. Characteristics and differences in ADCs curves of three salivary glands before and after stimulation between two stimuli were analyzed. Comparison of maximum ADCs, maximum ADCs increase rates (IRs) and times to maximum ADCs(Tmax) between two stimuli was performed by using independent-samples t test. Correlation analysis between rest salivary flow rates and rest ADCs, the maximum salivary flow rates and ADCs after stimulation, the maximum salivary flow IRs and ADC IRs after stimulation were performed by using Pearson correlation test. Results In lemon juice stimulation group, the mean ADCs mostly showed a steady increase to peak values during the first DW MRI scan after stimulation in all glands, followed by a gradually decrease fluctuating slightly around the baseline values. In vitamin C stimulation group, the mean ADCs were significantly increased in all glands during the first DW MRI scan after stimulation, followed by a gradual upward trend till peak values. In lemon juice stimulation group, the mean Tmax of submandibular and sublingual glands[(184±122)s, (345±232)s, respectively] were significantly earlier than those[(454 ± 301)s, (528 ± 297)s, respectively] in vitamin C stimulation group (t=-3.517 and-2.548 respectively, P0.05). Conclusion MR DWI with transient stimulation using lemon juice is more stable for evaluating the physiologic changes of salivary glands in vivo.
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Objective To assess the diagnostic capability of spiral CT for giant pure seminoma in intraabdominal undescended testis.Methods Spiral CT of 6 cases with pure seminoma of inabdominal testes as proved by surgery and pathology were analyzed.All patients were male,and the age ranged from 31 to 45 years old with the mean of 35.2 years old.Results All tumors were located along the path of testicular descent on CT images.The arterial-supply of tumors all came from the testicular artery ipsilaterally.The draining vein could be seen between the mass and inferior vena cava or left renal vein in 5 cases.Isolaterally spermatic cord was absent in the inguinal region.Isolateral kidney was shifted upward.CT scans typically demonstrated a unilateral,mixed solid and cystic mass,with areas of solid located at the lateral aspect and areas of necrosis at the medial aspect.Contrast-enhanced CT scan showed mild enhancement of solid areas and band-like septal enhancement in areas of necrosis.There is no evidence of calcification or fat within the mass.Conclusion Spiral CT proves to be a very useful preoperative imaging modality for the giant intraabdominal seminoma.
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Objective To assess the value of contrast-enhanced computed tomography (CT) in the differentiation of benign solitary pulmonary nodules(SPN) from malignant ones.Methods Thirty-seven patients with solitary pulmonary nodules(≤3 cm phi)were examined by contrast-enhanced CT.Qualitative and quantitative characters of benign and malignant lesions were analysed after administration of Ultravist in order to evaluate the attenuation value of contrast-enhanced CT in the differentiation of benign SPN from malignant ones .Results A threshold value of 30 HU was selected on enhanced CT images to distinguish malignant( CT value≥30 HU)from benign( CT value
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Objective To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in the diagnose of prostatic cancer and benign prostatic hyperplasia (BPH), and to determine the correlation between dynamic MRI findings with angiogenesis.Methods Thirty-two cases of prostatic cancer and 40 cases of BPH underwent dynamic contrast-enhanced MRI.All the patients in this study were diagnosed by histopathology.The results of dynamic contrast-enhanced MRI were evaluated by early-phase enhancement parameters and time-signal intensity curves (SI-T curves), and the curves were classified according to their shapes as type Ⅰ, which had steady enhancement; type Ⅱ, plateau of signal intensity; and type Ⅲ, washout of signal intensity.The pathologic specimens of region of interest (ROI) were obtained, and HE staining, immunohistochemical vascular endothelial growth factor (VEGF), and microvessel density (MVD) measurements were performed.The relationships among dynamic contrast-enhanced MRI features, VEGF, and MVD expression were analyzed.Results In the early-phase enhancement parameters of dynamic contrast-enhanced MRI, onset time,maximum signal intensity, and early-phase enhancement rate differed between prostatic cancer and BPH(P
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Objective To summarize and analysis CT characteristics of traumatic adrenal hematomas.Methods There were 22 cases ofadrenal hematomas.The size, distribution and density of the adrenal hematomas on CT scanning, and the complications of other visceralinjury were analysed.Results 23 adrenal hematomas were found in 22 cases, of them,16 were in right,6 in left and 1 in bilateral. Conclusion CT has high value in diagnosis of the adrenal hematomas.
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Objective To evaluate the correlation between the irradiation dose and superparamagnetic iron oxide (SPIO) enhanced MR imaging of the irradiated liver. Methods 25 rabbits were separated randomly into 5 groups. 3 days after focal irradiation (0, 10, 20, 30 and 40Gy), MR imaging was performed before and after SPIO injection with TSE-T 2W sequence, and the number of Kupffer cell containing SPIO particles was counted. The characteristics of MR enhancement were evaluated according to the pathological findings.Results The liver injury induced by no less than 30Gy irradiation can be detected by SPIO-enhanced T 2 weighted imaging (P
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Objective To investigate the MR features of adenomyosis and its diagnostic value.Methods Forty-six patients with suspicious adenomyosis underwent preoperative ultrasound and MR exam.Inversion recovery sequence(IR)T 1-weighted images and turbo spin echo sequence(TSE)including T 1-weighted and T 2-weighted images were adopted.All patients were performed with contrast enhancement.Comparative analysis between MRI findings and pathology results was done. Results The diagnostic specificity,sensitivity and accuracy of MRI was 100%,94.74% and 97.14% respectively.The effect of MRI for diagnosis of adenomyosis was better than that of US significantly.All cases showed enlargement of uterus with regular contour.Diffuse and local thickening of junctional zone or low signal intensity lesion in outer myometrial layer was found on T 2-weighted images,sometimes bright foci observed in lesion on T 2-weighted images or on T 1-weighted images.Conclusion MRI has high value in gualitative diagnosis and localization of adenomyosis.It can be used as an important complementary method to ultrasound.
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Objective To discuss the features of MRI and differential diagnosis of cerebral fat embolism syndrome(CFE).Methods The features of MRI of 4 final diagnosis cases of CEF were retrospectively analysed.Results MRI showed that there were spotty and patchy high T_2-weighted signals and some of them were low or equal signals on T_1-weighted.These signals were distributed in bilateral centrum semiovale,corona radiata,thalamus,deep part white matter of brain along the lateral ventricle,the cortex of brain of watershed,collose,brain stem and the hemisphere of cerebellum.The position of these abnormal signals was symmetric in the rough.The figure of the MRI signals in the midbrain liked the reverse Chinese number "eight".Brain swelling was showed in 2 of 4 cases.Conclusion There are some features of the CEF on T_2-weighted of MRI,but the history,the physical signal and the results of laboratory must be considered,and must be differential diagnosed with the diseases liking diffuse axonal injury,etc.
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Objective To discuss the imaging diagnostic value using seven division for dystopic thymomas in mediastinum. Methods 11 cases of dystopic thymomas proved by biopsy and histopathology were analyzed based on chest radiography, computed tomography (CT) and magnetic resonance imaging (MRI) .Results According to nine division, 3 cases located in left mid-middle and mid-inferior mediastinum, 4 cases in right mid-middle and mid-inferior mediastinum, 4 cases in right ante-middle and ante-inferior mediastinum.While according to seven division,all cases (11) located in ante-inferior mediastinum. Conclusion Seven division of mediastinum is of great value in diagnosing dystopic thymomas and in guiding clinical management.
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Objective To study the clinial application value of MR dispersion arthrography in meniscus tear of knee.Methods The conventional MR scans of 24 knee joints in 24 patients who were considered to have meniscus tear were performed and followed by MR dispersion arthrography.All cases were approved by arthroscope or operation.The results of both convention MR scan and MR arthrography were compared with arthroscope and operation.The sensitivity and the specificity of plain MR scan and MR dispersion scan were evaluated respectively.Results The signal intensity in the area of meniscus tear was obiously highen on MR dispersion scan than that of MR plain scan.The sensitivity was improved from 74.2% to 94.3% ,and the specificity improved from 88% to 94.3%.Conclusion MR dispersion scan is superior to convention MR scan in image quality and sensitivity in detecting meniscus tear.
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Objective To analyze the MRI manifestations of meningeal carcinomatosis, and to investigate the value of MRI in diagnosis of meningeal carcinomatosis.Methods The MRI data of 28 cases with proven meningeal carcinomatosis were reviewed retrospectively.Results 11, 8 and 25 cases were detected respectively on pre-contrast T 2WI and T 1WI of SE sequence , and post-contrast T 1WI.According to the manifestations of post-contrast MRI, meningeal carcinomatosis were divided into two types: dura-arachnoid enhancement(7 cases) and pia-subarachnoid space enhancement(18 cases) in accordance with the standard of Meltzer.Conclusion MRI, especially the post-contrast MRI is a reliable modality in diagnosis of meningeal carcinomatosis. Double dosage of contrast medium and thin slice thickness can provide more informations.
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Objective To assess the value of CT in diagnosis of recurrent rectal carcinoma.Methods Forty seven patients who had undergone locally curative surgery were examined by CT.All patients received intravenous contrast medium and two oral doses and a intrarectal doses of 500 ml 3% Ultravist were given.The characters of benign and malignant lesions were analysed in order to evaluate the value of the classification on CT in the differentiation of benign masses from malignant ones.Results 26 local recurrences occurred in 47 cases,including 13 cases with an round preasacral mass,8 cases with an irregular rectal wall thickening,2 cases with a flat preasacral mass,3 cases with a preasacral mass with low attenuation.The degree of enhancement of local recurrent masses was higher than that of benign masses.Conclusion The features of recurrence of rectal carcinoma on CT is an round or irregular asymmetrical preasacral mass or an irregular rectal wall thickening.It is useful way in diagnosis of recurrence of rectal carcinoma.