[Imaging findings of carcinoma ex pleomorphic adenoma in minor salivary glands].

PURPOSE: To summarize the CT and MR imaging features of carcinoma ex pleomorphic adenoma(Ca-ex-PA) in minor salivary gland, and analyze the correlation between various features and pathological classification. METHODS: Forty-three patients with Ca-ex-PA in minor salivary gland were collected. The CT and MRI findings were retrospectively analyzed and correlated with their pathological types. Fisher's exact test was used to analyze the correlation between various imaging features (tumor morphology, boundary, internal structure, bone invasion, cervical lymph node metastasis) and pathological types with SPSS 25.0 software package. RESULTS: Among the 43 patients with Ca-ex-PA, 83.7%(36/43) of the tumors were lobulated; 81.4%(35/43) showed cystic degeneration or necrosis, with heterogeneous enhancement. Coarse calcification or mixed calcification was found in 37.2%(16/43), 25.6%(11/43) had compressive absorption of adjacent bone. 75%(12/16) of type Ⅰ/Ⅱ tumors had regular morphology (round or oval), and 77.8%(21/27) of type Ⅲ tumors had irregular morphology, 93.8%(15/16) of type Ⅰ/Ⅱ tumors had well-defined margin and 66.7%(18/27) of type Ⅲ tumors had ill-defined margin. Osteolytic bone resorption occurred in 59.3%(16/27) of type Ⅲ tumors. The average maximum diameter of type Ⅰ/Ⅱ tumors was significantly shorter than that of type Ⅲ(P＜0.05). Fisher's exact test showed the characteristics of tumor morphology, boundary and osteolytic bone resorption were related to pathological grouping(P＜0.001). CONCLUSIONS: Most Ca-ex-PA in minor salivary glands is characterized by lobular and heterogeneous enhanced neoplasm on CT and MR imaging. A round or oval tumor with well-defined margin usually correlates with typeⅠ and Ⅱ, contrarily, an irregular mass with ill-defined margin and osteolytic bone destruction usually correlates with type Ⅲ. Combining the three characteristics of morphology, boundary and osteolysis is more helpful to distinguish type Ⅰ/Ⅱ and type Ⅲ tumors.

[MRI findings of parotid acinic cell carcinoma in 19 consecutive cases].

PURPOSE: To describe the MRI features of acinar cell carcinoma of parotid gland (AciCC) and to evaluate the diagnostic value of MR functional imaging. METHODS: A total of 269 cases of maxillofacial AciCC confirmed by surgery and pathology were analyzed. Among them, nineteen subjects with AciCC in the parotid gland underwent preoperative MRI examination (non-enhanced scan for one case, enhanced scan for 18 cases), seventeen patients underwent diffusion-weighted imaging scan, and 15 patients underwent dynamic contrast-enhanced scan. MRI findings of 19 patients were retrospectively analyzed. The lesion size, location, morphology, margin, internal composition, enhancement pattern and functional imaging characteristics were analyzed. SPSS 25.0 software package was used for statistical analysis. RESULTS: Among 269 cases of maxillofacial AciCC, there were 108 males and 161 females, male: female = 1:1.49, aged from 4 to 89 years, with a mean age of (45.95±17.33) years. 84.4% (227/269) were located in the parotid gland. On MRI images, 78.9% (15/19) had well-defined margin, 57.9% (11/19) were round or oval, and 36.8% (7/19) were lobed nodules. One case had irregular morphology and peripheral invasion. The range of maximum diameter was 6-56 mm, averaging (24.8±15.3) mm. Internal composition showed 57.9% (11/19) were cystic solid, 42.1% (8/19) were solid, 31.6% (6/19) had bleeding. T2-weighted MRI showed 52.6% (10/19) with envelope structure, 15.8% (3/19) with low signal separation inside, 38.9%(7/18) had uniform enhancement, and 61.1%(11/18) had uneven enhancement. Functional imaging showed the mean ADC value of tumor was (1.026±0.194)×10-3 mm2/s(n=17). 86.7%(13/15) TIC was type Ⅱ. CONCLUSIONS: Most maxillofacial AciCC are located in the parotid gland. It is difficult to distinguish AciCC from benign tumors with conventional MRI in morphology. The ADC value of AciCC is lower than that of benign tumors, and the type of TIC curve is mostly type Ⅱ. Combination of morphology and functional imaging can improve the diagnostic accuracy of this disease.

[Shanghai municipal expert consensus on standardized prevention and control of COVID-19 during procedures of oral radiology].

The announcement of National Health Commission on January 20, 2020 (No.1 of 2020) has included novel coronavirus pneumonia into the B class infectious diseases according to the law of the People's Republic of China on the prevention and control of infectious diseases, and has been managed as A class infectious diseases. People's governments at all levels and health administration departments have been paying high attention to it. With the alleviation of COVID-19 nationwide, dental clinics gradually resume to work. The main transmission routes of COVID-19 are respiratory droplets and contact transmission, hence oral radiological examination is kind of a high-risk operation. Standardized radiologic process is of great significance to reduce the risk of COVID-19 transmission. In accordance with the national and Shanghai epidemic prevention requirements, and in combination with the actual situation of various medical institutions, Oral and Maxillofacial Radiology Committee of Shanghai Stomatological Association formulated the expert consensus on standardized prevention and control of COVID-19 for clinical reference. This recommendation will be updated according to the situation of epidemic prevention and control in China and the new relevant diagnosis and treatment plans.

Targeted molecular imaging of head and neck squamous cell carcinoma: a window into precision medicine.

Tumor biomarkers play important roles in tumor growth, invasion, and metastasis. Imaging of specific biomarkers will help to understand different biological activities, thereby achieving precise medicine for each head and neck squamous cell carcinoma (HNSCC) patient. Here, we describe various molecular targets and molecular imaging modalities for HNSCC imaging. An extensive search was undertaken in the PubMed database with the keywords including "HNSCC," "molecular imaging," "biomarker," and "multimodal imaging." Imaging targets in HNSCC consist of the epidermal growth factor receptor, cluster of differentiation 44 variant 6 (CD44v6), and mesenchymal-epithelial transition factor and integrins. Targeted molecular imaging modalities in HNSCC include optical imaging, ultrasound, magnetic resonance imaging, positron emission tomography, and single-photon emission computed tomography. Making the most of each single imaging method, targeted multimodal imaging has a great potential in the accurate diagnosis and therapy of HNSCC. By visualizing tumor biomarkers at cellular and molecular levels in vivo, targeted molecular imaging can be used to identify specific genetic and metabolic aberrations, thereby accelerating personalized treatment development for HNSCC patients.

Selection and application of coils in temporomandibular joint MRI.

OBJECTIVE: To compare and evaluate the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) values between a 15-channel phased array head coil and 6-channel dS Flex M surface coil in the MRI of temporomandibular joint. METHODS: 300 patients were randomly assigned to two groups: 150 patients were examined by using a 15-channel phased array head coil and the other 150 patients were scanned by using a 6-channel dS Flex M surface coil. All of the data were set in the same 6 regions of interest including the temporal lobe, condyle neck, lateral pterygoid muscle, parotid gland, the adipose area and an area of the background noise）. SNR and CNR values were measured respectively. RESULTS: The numerical variation law of SNR and CNR values measured in regionsof interest of each group was similar, although different coils were used. There were statistically significant differences of SNR values in all of the oblique sagittal (OSag) proton density-weighted imaging, the part of OSag T 2 weighted image (T 2WI) except for SNR4 and SNR5. and oblique coronal (OCor) T 2WI sequence except for SNR2. On the contrary, SNR4 and SNR5 values in the OCor T 2WI and SNR5 values in OSag T 2WI sequences by using the surface coil were higher than those by using the head coil. There were no statistically significant intergroup differences of CNR values in OSag proton density-weighted imaging sequence except CNR1 and in OSag T 2WI sequence except CNR5. But, statistically significant differences of all the values in the OCor T 2WI sequence except for CNR1 were observed. CONCLUSION: Both the phased array head coil and dS Flex M surface coil can be used for temporomandibular joint MRI.

Histogram analysis of apparent diffusion coefficient maps in the prognosis of patients with locally advanced head and neck squamous cell carcinoma: Comparison of different region of interest selection methods.

OBJECTIVE: To investigate the influence of different region of interest (ROI) selection methods on the histogram analysis of apparent diffusion coefficient (ADC) maps and to compare their performance in predicting overall survival (OS) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). METHODS: A total of 73 patients with locally advanced HNSCC who underwent pretreatment diffusion-weighted magnetic resonance imaging were included. Based on the largest slice ROI (ROILS) and whole tumor ROI (ROIWT), ADC histogram parameters including mean ADC (ADCmean); median ADC (ADCmedian); 10th, 25th, 75th, and 90th percentiles of ADC values (ADC10, ADC25, ADC75, and ADC90); kurtosis; and skewness were obtained. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to evaluate measurement reproducibility. The association of ADC histogram parameters and clinicopathological factors with OS was analyzed using log-rank tests and Cox regression. RESULTS: The measurements of ADC histogram parameters based on ROIWT showed better reproducibility than ROILS (ICCs for ROIWT: 0.772-0.961; ICCs for ROILS: 0.511-0.851). The higher ADC values (ADCmean, ADCmedian, ADC10, and ADC25 based on both ROIs; ADC75 based on ROILS) and lower kurtosis based on ROILS were significantly associated with worse OS of patients with locally advanced HNSCC (all P < 0.05). In the multivariate Cox analysis, ADC10 measured with ROIWT (P = 0.019, hazard ratio = 2.63, 95% confidence interval 1.17-5.90) was an independent prognostic factor after adjusting for clinicopathological factors. CONCLUSIONS: ROI selection methods could influence ADC histogram analysis. ADC10 based on ROIWT had the best independent prognostic value for patients with locally advanced HNSCC.

[Clinical analysis of spectrum CT imaging reducing metal artifacts of oral and maxillofacial region].

PURPOSE: To assess the capability of monochromatic energy images of gemstone spectral imaging(GSI) by using spectral CT in reducing metal artifacts of oral and maxillofacial region. METHODS: Spectral CT imaging was applied to 46 patients with metallic implants with GSI sequence to measure CT numbers (expressed in Hounsfield units, HU) and SD (standard deviation) numbers of the soft tissues. 11 monochromatic-image groups were obtained, ranging from 40 keV(kiloelectronvolts) to 140 keV (every 10 keV as one group). The data were analyzed with SPSS19.0 software package. RESULTS: Images in 20 subjects with orthodontic appliance, the minimal average AI ranged between (23.86±10.90) to (24.42±11.54) HU. Similarly, in 12 subjects with titanium implants, the minimal average AI ranged between (26.49±9.40) to (26.95±8.97) HU. In 10 images from 14 subjects with dental fillings or fixed dentures, the minimal average AI ranged between (29.84±13.04) to (30.97±13.15) HU. The average AI values were (63.36±70.52), (70.82±105.14) and (107.35±147.57) HU from 40 keV to 140 keV in 3 groups, respectively, which was similar to the average AI values of 70keV monochromatic images (61.46±32.06, 70.18±62.86, 110.28±78.70) HU in each corresponding group. There was a significant difference about AI value among 3 energy spectrum groups (P<0.05). CONCLUSIONS：Spectral CT imaging could obviously reduce metal artifacts, and improve the display capabilities of the structures around the metallic implants. 70 keV is the dividing point of metal artifact subtraction. The optimal energy range is at 110-140 keV in reducing metal artifacts of oral and maxillofacial region.

[Case-based learning based on CBCT software in clinical teaching of oral and maxillofacial radiology].

PURPOSE: To compare the teaching result of case-based learning based on cone-beam CT (CBCT) software and traditional pantomography. METHODS: Thirty-eight interns (7-year programme) of grade 2011 from College of Stomatology, Shanghai Jiao Tong University were enrolled. The inner diameter of the nasopalatine ducts (A), the length of upper canine's pulp cavity (B), the length between root furcation of upper first molar and the maxillary sinus (C), the length between the root of lower wisdom tooth and the inferior alveolar nerve (D) were measured on pantomographic films and CBCT in the same case. The results of 38 interns were evaluated by Chi-square test with SPSS 16.0 software package. A questionnaire, given to the whole group of interns, was used to evaluate the teaching effect and the understanding of the 2D and 3D conception of the radiologic films. RESULTS: Only 3 data A, 14 data B, 10 data C, and 16 data D were measured on pantomography, respectively. Thirty-eight data A, 36 data B, 37 data C, and 38 data D were measured on CBCT. Significant difference was found between measurements on CBCT and pantomography in 4 groups (P<0.05). 38 interns finished the questionnaires survey. More than 95% interns delivered positive comments in inspiring interest, deepening knowledge, improving clinical thinking ability, and etc. CONCLUSIONS: Case-based learning based on CBCT software for measuring anatomic structures and building 3D concept can improve the quality in oral and maxillofacial radiology learning, deepen the understanding of the specialty, and increase efficacy of clinical teaching.

Thin-section computed tomography-histopathologic comparisons of pulmonary focal interstitial fibrosis, atypical adenomatous hyperplasia, adenocarcinoma in situ, and minimally invasive adenocarcinoma with pure ground-glass opacity.

OBJECTIVE: To retrospectively compare focal interstitial fibrosis (FIF), atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), and minimally invasive adenocarcinoma (MIA) with pure ground-glass opacity (GGO) using thin-section computed tomography (CT). MATERIALS AND METHODS: Sixty pathologically confirmed cases were reviewed including 7 cases of FIF, 17 of AAH, 23of AIS, and 13 of MIA. All nodules kept pure ground glass appearances before surgical resection and their last time of thin-section CT imaging data before operation were collected. Differences of patient demographics and CT features were compared among these four types of lesions. RESULTS: FIF occurred more frequently in males and smokers while the others occurred more frequently in female nonsmokers. Nodule size was significant larger in MIA (P<0.001, cut-off value=7.5mm). Nodule shape (P=0.045), margin characteristics (P<0.001), the presence of pleural indentation (P=0.032), and vascular ingress (P<0.001) were significant factors that differentiated the 4 groups. A concave margin was only demonstrated in a high proportion of FIF at 85.7% (P=0.002). There were no significant differences (all P>0.05) in age, malignant history, attenuation value, location, and presence of bubble-like lucency. CONCLUSION: A nodule size >7.5mm increases the possibility of MIA. A concave margin could be useful for differentiation of FIF from the other malignant or pre-malignant GGO nodules. The presence of spiculation or pleural indentation may preclude the diagnosis of AAH.

Advantage in Bright-blood and Black-blood Magnetic Resonance Imaging with High-resolution for Analysis of Carotid Atherosclerotic Plaques.

BACKGROUND: About 50% of the cerebral ischemia events are induced by intracranial and extracranial atherosclerosis. This study aimed to evaluate the feasibility and accuracy for displaying atherosclerotic plaques in carotid arteries and analyzing their ingredients by using high-resolution new magnetic resonance imaging (MRI) techniques. METHODS: Totally, 49 patients suspected of extracranial carotid artery stenosis were subjected to cranial MRI scan and magnetic resonance angiography (MRA) examination on carotid arteries, and high-resolution bright-blood and black-blood MRI analysis was carried out within 1 week. Digital subtraction angiography (DSA) examination was carried out for 16 patients within 1 month. RESULTS: Totally, 103 plaques were detected in the 49 patients, which were characterized by localized or diffusive thickening of the vessel wall, with the intrusion of crescent-shaped abnormal signal into lumens. Fibrous cap was displayed as isointensity in T1-weighted image (T1WI) and hyperintensities in proton density weighted image (PDWI) and T2-weighted image (T2WI), lipid core was displayed as isointensity or slight hyperintensities in T1WI, isointensity, hyperintensities or hypointensity in PDWI, and hypointensity in T2WI. Calcification in plaques was detected in 11 patients. Eight patients were detected with irregular plaque surface or ulcerative plaques, which were characterized by irregular intravascular space surface in the black-blood sequences, black hypointensity band was not detected in three-dimensional time-of-flight, or the hypointensity band was not continuous, and intrusion of hyperintensities into plaques can be detected. Bright-blood and black-blood techniques were highly correlated with the diagnosis of contrast-enhanced MRA in angiostenosis degree, Rs = 0.97, P < 0.001. In comparison to DSA, the sensitivity, specificity, and accuracy of MRI diagnosis of stenosis for ≥50% were 88.9%, 100%, and 97.9%, respectively. CONCLUSIONS: High-resolution bright-blood and black-blood sequential MRI analysis can accurately analyze ingredients in atherosclerotic plaques. Determined by DSA, MRI diagnosis of stenosis can correctly evaluate the serious degree of arteriostenosis.

Dynamic MR imaging of temporomandibular joint: an initial assessment with fast imaging employing steady-state acquisition sequence.

PURPOSE: The study was aimed to determine and optimize the parameters for the MR fast imaging employing steady-state acquisition (FIESTA) sequence, which was to obtain an acceptable image to evaluate the value of the movement of the temporomandibular joint (TMJ). METHODS: In this investigation, 20 volunteers were examined to determine and optimize the parameters of the FIESTA sequence. Then, 160 TMJs from 80 patients with temporomandibular joint disorders (TMD) of clinical suspicion were consecutively performed by both static MRI and dynamic FIESTA MRI on the oblique sagittal position. The FIESTA MR images of TMJs were obtained from a slow, consecutive, free and open-closed movement. Based on the cycles of TMJ movements during the process of FIESTA MRI (90seconds), we classified all TMJs into 2 groups: cycles of open-closed mouths less than or equal to 3 (group 1) and more than 3 (group 2). Each image was marked level 1-3 by its quality. Meanwhile, the location of articular disc, mandibular condyle, motive artifact, "jumping sign" and the joint effusion in each TMJ were assessed respectively. RESULTS: By dynamic FIESTA MRI among 160 TMJs, 92 TMJs (57.50%) were in group 1, and 68 TMJs were (42.50%) in group 2. There were statistically significant differences between group 1 and group 2(p<0.05). It was shown that the number of "level 3" in group 1 was greater than group 2, and the number of "level 1" in group 1 was less than group 2. The phenomenon of motion artifact and "jumping sign" were much significantly higher in group 2 than those in group 1 (p<0.01). Furthermore, in all of the "jumping sign" cases, the phenomenon of "jumping sign" was significantly higher in group ADDwR than in group ADDw/oR (p<0.01). There was a statistically significant correlation between disc-condyle complex in "jumping sign" phenomenon and group ADDwR (r=0.621, p<0.05). The data with the false matching rate of 31.52% showed that the maximum motion range on the dynamic imaging was greater than the static imaging. Among 160 TMJs, joint effusions of 37 TMJs (23.13%) were identified by dynamic FIESTA-MRI. Among 79 TMJs with ADDw/oR(anterior disc displacement without reduction), 42 sides were operated with Maxillofacial arthroscopy surgery. The surgical result was in agreement with the MR result. CONCLUSION: Most TMJs images with a slow free open-close movement (cycles≦3) could be successfully obtained by the dynamic FIESTA MRI. The FIESTA MRI might be considered as an additional method to evaluate the movement of the articular disk and the mandibular condyle.

Spontaneous osteosarcoma in craniomaxillofacial fibrous dysplasia: clinical and computed tomographic features in 8 cases.

OBJECTIVE: The aim of this study was to evaluate the patient demographic and computed tomography (CT) imaging findings of spontaneous osteosarcoma in craniomaxillofacial fibrous dysplasia. STUDY DESIGN: Ten cases of spontaneous osteosarcoma in craniomaxillofacial fibrous dysplasia diagnosed during 1993-2013 were reviewed. Eight cases with CT images were reviewed. RESULTS: The mean age of diagnosis of osteosarcoma was 37.8 years (range, 8-55 years). The presence of a soft tissue extension component beyond the area of cortical bone destruction was demonstrated radiographically in 7 out of 8 cases. Mineralization of tumor matrix was seen in 6 cases. Periosteal reaction was demonstrated in only 1 case; 1 out of 6 cases showed significant enhancement on postcontrast CT images. Nine patients had surgical resections of tumor. Seven of them died of tumor, with a mean survival time of 5.3 years. CONCLUSIONS: This study provides CT imaging features with clinical information of spontaneous osteosarcoma in craniomaxillofacial fibrous dysplasia.

Assessment of dynamic contrast-enhanced magnetic resonance imaging in the differentiation of malignant from benign orbital masses.

OBJECTIVE: Dynamic contrast enhanced MR imaging (DCE-MRI) allows imaging of the physiology of the microcirculation. The purpose of this study was to determine the diagnostic efficacy of time intensity curve (TIC) and DCE parameters for characterization of orbital masses. METHODS: Fifty-nine patients with untreated orbital lesions underwent DCE-MRI before surgery. For each lesion, peak height (PH), maximum enhancement ratio (ERmax), time of peak enhancement (Tpeak) and maximum rise slope (Slopemax) were plotted and calculated. Receiver operator characteristics (ROC) analysis was conducted to assess the appropriate cut-off value. RESULTS: All 26 lesions that demonstrated persistent pattern (type-I) TICs were benign. Most of the masses with the washout pattern (type-III) TIC were malignant (10/14), including lymphoma (n=6) and melanoma (n=4). The Slopemax of benign lesions was statistically lower than malignant ones, while the ERmax and Tpeak values of benign lesions were significantly higher. No statistical difference was found in PH (P=0.121). The AUC for ERmax, Tpeak and Slopemax in differentiating benign orbital lesions from malignant ones were 0.683, 0.837 and 0.738, respectively. In the three DCE parameters, Slopemax cut-off value of 1.10 provided the highest sensitivity of 93.8%; however, the corresponding specificity was low (58.1%). The ERmax cut-off value of 1.37 and Tpeak cut-off value of 35.14 respectively offered the best diagnostic performances. CONCLUSION: DCE-MRI, especially the qualitative TIC pattern and quantitative value of Slopemax, ERmax and Tpeak, could be a complementary investigation in distinguishing malignant orbital tumor from benign ones.

Dual-energy computed tomography angiography for evaluating the renal vascular variants.

BACKGROUND: Recognizing renal vascular variants preoperatively is important in order to avoid vascular complications during surgery. This study aimed to investigate the renal vascular variants with dual-energy computed tomography (DECT) angiography to provide valuable information for surgery. METHODS: A total of 378 patients underwent DECT. The number, size, course and relationships of the renal vessels were retrospectively observed from the scans. Anomalies of renal arteries and veins were recorded and classified. Multiplanar reformations (MPR), maximum intensity projections (MIP), and volume renderings (VR) were used for analysis. RESULTS: In 378 patients (756 kidneys), renal artery variations were discovered and recorded in 123 kidneys (16.3%, 123/756) of 106 patients (28.0%, 106/378). Type IB (early branches of the only one main renal artery) and IC (accessory renal artery with only one main renal artery) were found most frequently with an incidence of 11.4% (43/378) and 14.5% (55/378). The incidence of renal artery variations in the left kidney was not statistically different than in the right kidney (12.4% vs. 11.1%). The incidence of renal vein variations was detected in 104 patients (27.5%, 104/378). The incidence of venous variants in the right kidney was higher than in the left kidney (20.1% vs. 7.4%), but left renal vein variations were more complex. Variants of the left renal vein were detected in 28 patients including type 1 (circumaortic left renal vein) in eight cases, type 2 (retroaortic left renal vein) in seven cases, type 3 (abnormal reflux) in six cases, type 4 (late venous confluence of left renal vein) in five cases, and type 5 (rare type) in two cases. The frequency of left renal vein variation associated with the left renal accessory artery was significantly higher than with early branches of the left renal artery (P = 0.037). CONCLUSIONS: The renal vascular variants are rather common and complex. DECT angiography can demonstrate the precise anatomy of the renal vessels, which is a benefit for renal transplantation or other renal operations.

Calcified cerebral cryptococcal granuloma.

The authors report a 12-mo-old girl with calcified cerebral cryptococcal granuloma. She was admitted with a 6-mo history of seizures. Laboratory examinations showed no abnormal findings. Electroencephalography revealed bilateral slow wave activity, greater in the right occipital region. CT showed an irregular calcified focus with small surrounding low density in the right parieto-occipital region. MRI demonstrated mixed signals without edema and visible flow-voids. The clinical symptoms mimicked intracranial vascular malformations. The diagnosis of cerebral cryptococcal granuloma was made by histopathology. Partial resection of the lesion with post-operatively antifungal and anticonvulsant therapy offered the satisfactory result. Cerebral cryptococcal granuloma is extremely rare, especially in infants. Calcification is indeed unusual. Cerebral cryptococcal granuloma should be included in the differential diagnosis of intracranial mass with calcification in infants.

[Application of apparent diffusion coefficient ratio in the diagnosis of bladder cancer grading pre-operation].

OBJECTIVE: To explore the value of apparent diffusion coefficient (ADC) ratio in the diagnosis of bladder cancer pre-operation by analyzing its differences among different grades of bladder cancer. METHODS: A total of 52 cases of bladder cancer were all definitely diagnosed with histological results.Routine examinations of magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) were performed preoperatively on each patient. ADC map was constructed in work station and ADC values of tumor and internal obturator muscle were measured (b = 800 s/mm(2)).Ratio of ADC was calculated with internal obturator muscle as reference site. Then the relationship between ADC ratio and bladder cancer grade was analyzed. RESULTS: Mean ratio of ADC of all tumors was 0.98±0.35, G1 (1.12±0.21) and G2 (0.67±0.29), the sensitivity and specificity of ADC ratio was 90.2% and 85.3% respectively with an optimal threshold of 0.96. The ratios of ADC of low-grade group were significantly higher than those of high-grade group while the values of non-muscle-invasive group were significantly higher than those of muscle-invasive group. The ratios of ADC of tumor were inversely associated with the malignancy degree of bladder cancer (r = -0.845, P < 0.05). CONCLUSION: The ratio of ADC of bladder cancer reflects the lesion tissue properties. And its measurement plays an important role in the diagnosis of bladder cancer grading pre-operation.

Initial HRCT findings of novel influenza A (H1N1) infection.

OBJECTIVES: The aim of our study was to describe the presentation and illustrate the imaging features of chest high-resolution computed tomography (HRCT) of patients with novel influenza A (H1N1) virus infection. METHODS: Data were collected from 163 hospitalized patients between November 2009 and March 2011, who fulfilled the clinical criteria for H1N1 influenza infection and underwent HRCT examinations within 24 hours of admission. RESULTS: Abnormal findings were observed in 40.5% of the patients. The patients with positive imaging findings were significantly older than patients with normal HRCT findings (P=0.02). The most common finding was ground-glass opacity (GGO) (n=35). Interlobular septal thickening (n=31) and centrilobular nodules (n=30) were the second most frequent findings. Other common findings were consolidation, reticulation, and linear shadow. The most common imaging finding for lung involvement was GGO with a patchy pattern. Pulmonary involvement of the disease may be extensive and variable, but the total volume of affected lung was mostly <1 lobe. CONCLUSION: The baseline HRCT may be valuable and suggestive even for non-severe H1N1 infections. When a severe case or a evolution is suspected, chest CT could be essential both for determining the precise extent of parenchymal damage and for monitoring its evolution.

The diagnostic value of dynamic contrast-enhanced MRI for thyroid tumors.

BACKGROUND AND PURPOSE: The exact place for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the diagnosis and management of thyroid tumors is still under debate. We performed the study to analyze and compare the parameters generated from DCE-MRI for thyroid lesions. MATERIALS AND METHODS: For each thyroid lesion, time intensity curves (TIC), time of peak enhancement (Tpeak), maximum enhancement ratio (ERmax) and maximum rise slope (Slopemax) were plotted and calculated. Receiver operator characteristics (ROC) analysis was conducted to assess the diagnostic ability and appropriate cut-off value. The area under the ROC curve (AUC) and the confidence intervals (CIs) were also assessed. RESULTS: Forty-two patients were consecutively included. All 21 lesions demonstrated the rapid inflow and washout pattern (type-I) were benign. The 12 cases with delayed inflow pattern (type-III) were all malignant. When compared with the benign lesions, the thyroid carcinoma showed significantly lower Slopemax and higher Tpeak (P<0.05). No statistical difference of ERmax was found between malignant and benign ones (P=0.15). The AUC of ERmax, Slopemax and Tpeak in differentiating benign thyroid lesions from malignant ones were 0.63, 0.93 and 1, respectively. The ERmax cut-off value of 73.86 (sensitivity, 71.4%; specificity, 64.3%), Slopemax cut-off value of 2.4126 (sensitivity, 92.9%; specificity, 82.1%) and Tpeak value of 28 (sensitivity, 100%; specificity, 100%) offered the best diagnostic performances. CONCLUSIONS: DCE-MRI, especially the pattern of TIC and the value of Slopemax and Tpeak, could be helpful in differentiating thyroid carcinoma from benign thyroid lesions.