[The value of dynamic contrast-enhanced MRI in the differentiation between benign and malignant lacrimal epithelial tumors].

Objective: To investigate the diagnostic performance of multiparametric dynamic contrast-enhanced MRI(DCE-MRI) for the differentiation between benign and malignant larcrimal gland epithelial tumors. Methods: The clinical and imaging data of 104 patients with epithelial tumors of the lacrimal gland who underwent orbital MRI scan and met the inclusion criteria in Beijing Tongren Hospital from January 2011 to December 2017 were retrospectively collected, including 48 males and 56 females, aged from 12 to 77 (43±7) years. Sixty-three cases of benign epithelial tumors and 41 cases of malignant epithelial tumors were examined by DCE-MRI. The parameters of semiquantitative analysis including: time to peak enhancement (Tpeak), maximum enhancement ratio (ERmax), Slope, washout ratio (WR) and time-signal intensity curve (TIC) types. The parameters of quantitative analysis including: volume transfer constant (Ktrans), the extravascular extracellular volume fraction (Ve) and rate constant (Kep). Receiver operating characteristic (ROC) curve analysis was performed for DCE-MRI parameters with statistically significant differences, the area under the curve (AUC) was calculated, the diagnostic threshold was determined, and the diagnostic performance was evaluated. Logistic regression analysis was used to determine the best parameters for differential diagnosis of benign and malignant epithelial tumors of the lacrimal gland. Results: For the semiquantitative analysis of DCE-MRI, malignant lacrimal gland epithelial tumor had a significantly shorter Tpeak than benign masses [(103.77±57.87) s vs (187.80±77.01) s,P<0.001)], while had a higher value in ERmax, Slope [M(Q1,Q3)] and WR in malignant masses compared with benign one [1.55±0.39 vs 1.36±0.33; 1.76 (0.97,2.27) vs 0.62 (0.50,0.93); 7.70%(1.40%, 21.60%)% vs 0(0, 0),all P<0.05)].The TICs of benign lacrimal tumors mainly showed a persistent type (49/63),while most malignant lacrimal tumors mainly showed a plateau type (25/41). For the quantitative analysis of DCE-MRI, the values of Ktrans and Kep[M(Q1,Q3)] in malignant tumors were significantly greater than those of benign tumors (0.99±0.52/min vs 0.43±0.23/min, P<0.001; 1.33(0.83, 1.55)/min vs 0.55(0.46, 0.68)/min, P<0.001). No significant difference in Ve was found between the groups (0.76±0.20 vs 0.73±0.22,P=0.467). Through the statistical analysis, TIC types (OR=3.887,95%CI: 1.409-10.725) and Ktrans(OR=50.979,95%CI: 6.046-429.830) can provide superior diagnostic performance for predicting malignant lacrimal gland epithelial tumors, with a sensitivity of 78.05%, specificity of 77.78%,and sensitivity of 70.73%, specificity of 95.24%, respevtively. Furthermore, the comprehensive diagnostic performance of Ktrans in AUC was proven to be significantly better than that of TIC [0.875 (0.796-0.932) vs 0.798 (0.708-0.870),P=0.049]. Conclusions: Multiparametric DCE-MRI is helpful for the differential diagnosis of benign and malignant epithelial tumors of lacrimal gland. TIC type and Ktrans have higher diagnostic value, and the diagnostic performance of Ktrans is better than that of TIC.

[The value of ultrasonic elastography in the differential diagnosis of choroidal melanoma and choroidal hemangioma].

Objective: To explore the role of the scoring and strain ratio methods of ultrasonic elastography in the differential diagnosis of choroidal melanoma and choroidal hemangioma. Methods: A cross-sectional study. Twenty-five patients (25 eyes) with choroidal melanoma treated in the Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University from July to October 2016 were included in this study. There were 13 males and 12 females, with an average age of (48±12) years old. Twenty-five patients (25 eyes) with choroidal hemangioma treated in the same period were selected for differential diagnosis, including 12 males and 13 females, with an average age of (37±13) years. The lesions were examined by ultrasound elastography and scored, and the strain ratio of the tumor to the orbital tissue was measured. Two independent sample t test was used to compare the difference in the elasticity score and strain ratio between choroidal melanoma and choroidal hemangioma. The sensitivity, specificity and area under the receiver operating characteristic (ROC) curve were calculated to analyze the value of the two methods in the differential diagnosis of choroidal melanoma and choroidal hemangioma. Results: The elastography score of choroidal melanoma was (3.48±0.77) points, including 2 points in 3 cases, 3 points in 8 cases, 4 points in 13 cases, and 5 points in 1 case. The elastography score of hemangioma was (2.28±0.46) points, including 2 points in 18 cases and 3 points in 7 cases. The difference in the elasticity score between patients with the two kinds of tumors was statistically significant (t=6.694, P<0.01). The strain ratio was 42.97±15.83 and 12.21±9.24 in the patients with choroidal melanoma and choroidal hemangioma, respectively, and the difference was statistically significant (t=8.392, P<0.01). Using 3 points as the diagnostic critical point of the elastography score, the sensitivity was 88.0%, the specificity was 72.0%, and the area under the ROC curve was 0.80 (95% cofidence interval: 0.663 to 0.900, P<0.01). Using 21.67 as the diagnostic critical point of the strain ratio, the sensitivity was 92.0%, the specificity was 92.0%, and the area under the ROC curve was 0.92 (95% cofidence interval: 0.808 to 0.978, P<0.01). Conclusions: Ultrasound elastography plays a role in the differential diagnosis of choroidal melanoma and choroidal hemangioma. The differential diagnostic value of the strain ratio method is higher than the scoring method. (Chin J Ophthalmol, 2020, 56: 676-680).

[The effect of genioglossus activity to velopharyngeal surgery in patient with obstructive sleep apnea hypopnea syndrome].

Objective: To investigate the effect of genioglossus (GG) activation at sleep onset on the outcome of velopharyngeal surgery in obstructive sleep apnea hypopnea syndrome (OSAHS) patients. Methods: Thirty-five patients between April 2014 and February 2015 in Beijing Tongren Hospital with OSAHS underwent overnight polysomnography with synchronous genioglossus electromyography (GGEMG) using intraoral electrodes. The upper airway (UA) anatomy was evaluated by three-dimensional computer tomography (3D-CT) in OSAHS patients. Then, all of the patients received velopharyngeal surgery, including revised uvulopalatopharyngoplasty (UPPP) with uvula preservation or UPPP combined transpalatal advancement pharyngoplasty. All patients were followed-up using polysomnography 3-6 months after surgery. T-test or Wilcoxon test were used to compare the variables between groups, and Spearman correlation analysis was used to test the correlation between parameters. Results: Thirty-five patients received velopharyngeal surgery. Twenty-two patients (62.86%) were responders, and 13 patients (37.14%) were non-responders. Responders had a higher mean GGEMG during sleep onset (15.31±3.74 vs. 9.92±2.93, t=4.504, P=0.001). The decreased AHI was significantly positively related to the sleep onset mean GGEMG (r=0.541, P=0.004) and the change in GGEMG (r=0.422, P=0.028). The decreased AHI was significantly negatively related to the minimal cross sectional airway area (mCSA,ρ=0.629,P=0.000) and the minimal lateral airway dimension (mLAT, ρ=0.484, P=0.009) at velopharynx. Conclusions: The outcome of velopharyngeal surgery was affected by the mean GGEMG during sleep onset. We speculated that the patient with higher GGEMG at sleep onset and narrower velopharynx were more suitable candidates for velopharyngeal surgery.

[Quantitative dynamic contrast enhancement MR imaging parameters in the prediction and evaluation of the treatment response of malignant sinonasal tumors to chemotherapy:a preliminary result].

Objective: To investigate the value of quantitative dynamic contrast enhancement MR imaging (DCE-MRI) parameters in the prediction and evaluation of the response to neoadjuvant chemotherapy in patients with malignant sinonasal tumors by comparing the parameter values before and after chemotherapy. Methods: DCE-MRI was performed in 14 patients (6 male cases, 8 female cases, 16-83 years) with malignant sinonasal tumors before chemotherapy in Beijing Tongren Hospital from January 2012 to December 2013 in which DCE-MRI was performed in 8 patients on the 7th, 21st and 42nd days after chemotherapy. The values of quantitative parameter including K(trans), K(ep), and V(e) of the tumor were assessed and the change rate of these quantitative parameter values after chemotherapy was calculated. Results: Response to chemotherapy of the tumor was found in 11 patients with malignant sinonasal tumors,whereas no response to chemotherapy of the tumor was confirmed in 3 patients. K(trans) ((0.75±0.28)/min) and K(ep) ((3.23±1.48)/min) values of the tumor before chemotherapy in patients with response to chemotherapy were significantly bigger than those ((0.43±0.41)/min, (1.34±0.42)/min) in patients with no response to chemotherapy (all P<0.01).There was no significant difference in V(e) values between two groups (P=0.165). Compared with K(trans) values of the tumor before chemotherapy,the change rate of K(trans) values decreased more than 40% on the 7th,21st and 42nd days after chemotherapy in the patients with treatment response,whereas the change rate did not decrease significantly in the patients without treatment response. Conclusion: The bigger K(trans) and K(ep) values of the tumor before chemotherapy,the better the treatment response of the tumor to chemotherapy.

[Application of MRI in the etiological diagnosis of special forms of strabismus].

Objective: To explore the imaging features of patients with special forms of strabismus and summarize the subtypes by using MRI imaging techniques. Methods: A retrospective case series study. Among the patients who visited the Beijing Tongren Hospital between 2006 and 2016, 1 113 patients were identified with special forms of strabismus after complete ophthalmic and orthoptic evaluations. These patients were further evaluated using several types of high-resolution MRI techniques of the oculomotor nerves in the brain, the cavernous sinus, and the orbits. Results: Among the 1 113 patients, 818 patients (73.5%) were identified with MRI abnormal conditions, and 295 patients (26.5%) were identified with MRI normal conditions. Nine different disease types were identified in the studied populations, which included 257 patients (23.1%) with congenital cranial dysinnervation disorders, 209 patients (18.8%) with thyroid associated ophthalmopathy, and 169 patients (15.2%) with abnormalities of the extraocular muscles. Other diseases included orbital fractures (3.3%, 37 patients), intraorbital inflammations (2.7%, 30 patients), tumors (2.3%, 26 patients), injuries of medial rectus muscle after endoscopic sinus surgery (1.2%,13 patients), and lesions of cavernous sinus (2.0%, 22 patients). Additional 55 patients (4.9%) were identified with other causes such as high myopia fixed esotropia, and so on. Conclusion: Summarizing the common clinical characteristics and rules with the help of MRI can further clarify the etiology of special forms of strabismus, and accurately guide the diagnosis and treatment of strabismus. (Chin J Ophthalmol, 2019, 55: 361-368).

[Value of the apparent diffusion coefficient in diffusion weighted imaging at 3.0T MR for differentiating lacrimal gland tumors].

Objective: To investigate the diagnostic value of apparent diffusion coefficient in diffusion weighted imaging at 3.0 T MR for the differentiation in the larcrimal gland tumors. Methods: A total of 73 cases, 36 males and 37 female; mean age 14-81(44±15)years, with lacrimal gland tumors confirmed by pathology in Beijing Tongren Hospital were retrospectively analyzed between January 2011 and April 2016.All cases underwent the preoperative routine MRI and DWI scan, the ADC values were measured in region of interest within the solid zone. The cases were divided into benign and malignant group by the histopathology, according the different pathological categories, the malignant cases were further divided into the epithelial and non-epithelial malignacy. The receiver operating characteristic curve (ROC) was constructed using various cut points of ADC for different parameters to confirm the diagnostic threshold value and evaluate the diagnostic efficacy. Results: There were totally 77 lesions in 73 cases, of which 69 involved unilateral lacrimal gland,4 bilateral lacrimal glands. The mean ADC value of malignant and benign masses in lacrimal gland was (1.36±0.16) and (0.90±0.30)×10(-3) mm(2)/s respectively. There was significantly statistical difference between the both(t=-8.319, P<0.01). The mean ADC value of epithelial and non-epithelial malignacy in lacrimal gland was (1.08±0.18) and (0.54±0.09)×10(-3) mm(2)/s respectively. There was significantly statistical difference between the both(t=11.988, P<0.01). The area under the ROC for distinguishing malignant from benign lesions was 0.940. Using an ADC value of 1.275×10(-3) mm(2)/s as the threshold value, the best result obtained had a sensitivity of 94.4%(34/36), specificity of 82.9%(34/41), accuracy of 88.3%(68/77). The area under the ROC for differentiating non-epithelial from epithelial malignacy was 1.0. Using an ADC value of 0.736×10(-3) mm(2)/s as the threshold value, the best result obtained had a sensitivity of 100%, specificity of 100%, accuracy of 100%. Conclusion: The ADC value is helpful in differentiation among different kinds of tumors in lacrimal masses.

[Value of DCE-MRI and DWI in the differential diagnosis of inflammatory pseudotumor and lymphoma in the lacrimal gland].

Objective: To evaluate the value of dynamic contrast-enhanced MR (DCE-MRI) and diffusion weighted MR (DWI) in differential diagnosis of inflammatory pseudotumor and lymphoma in the lacrimal gland. Methods: In this retrospective study, a total of 24 cases of inflammatory pseudotumor and 22 cases of lymphoma in the lacrimal gland at Beijing Tongren Hospital confirmed by histological results were enrolled from January 2010 to January 2015.DCE-MRI and DWI were performed in these cases, and the type of time-signal intensity curve (time-intensity curve, TIC), the peak contrast index (CIpeak), maximum enhancement ratio (ERmax), washout ratio (WR) and ADC value were analyzed.Differences of these parameters between inflammatory pseudotumor and lymphoma in the lacrimal gland was evaluated by independent samples t test or Mann-Whitney U test.The receiver operating characteristic analysis was used to evaluate the utility of these parameters in discriminating the two diseases. Results: Type of TIC, CIpeak, WR, ERmax and ADC values were statistically different (all P<0.05) between the inflammatory pseudotumor and lymphoma in the lacrimal gland.ERmax, CIpeak and ADC values of inflammatory pseudotumor were greater than those of lymphoma, but the WR values of inflammatory pseudotumor was less than those of lymphoma.The area under the ROC of the CIpeak, WR, ERmax and ADC values was 0.68±0.08, 0.70±0.08, 0.70±0.08, 0.84±0.81 respectively.Using an ADC(b=0, 1000) value of 1.005×10(-3) mm(2)/s as the diagnostic threshold, the sensitivity, specificity and accuracy to differentiate benign lesions from malignant lesions were 84.2%, 65.0% and 75.0% respectively.The diagnostic ability of DWI combined with DCE-MRI was superior to that of DCE-MRI(P=0.000) or DWI alone(P=0.008) with overall sensitivity, specificity and accuracy of 86.3%, 87.5% and 86.9%. Conclusion: DCE-MRI and DWI may improve the diagnostic accuracy in differentiation of the inflammatory pseudotumors and lymphomas in the lacrimal gland, and play an important role in differentiation among them.

Association between GSTM1, GSTT1, and GSTP1 polymorphisms and gastric cancer risk, and their interactions with environmental factors.

Glutathione S-transferase (GST) is an important member of phase II metabolic enzymes; GSTM1, GSTT1, and GSTP1 belong to three subfamilies of the GST enzyme. Polymorphisms in GSTM1, GSTT1, and GSTP1 could affect detoxification processes, and increase individuals' susceptibility to cancers. We aimed to investigate the association between GSTM1, GSTT1, and GSTP1 polymorphisms and the risk of gastric cancer in a Chinese population. In addition, we also examined the effect of gene-environmental interactions, and their effect on risk of this cancer. Between July 2013 and June 2015, we recruited 242 gastric cancer patients and 396 healthy controls for our study. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to characterize genetic polymorphisms in GSTM1, GSTT1, and GSTP1. We observed that the Val/Val genotype of GSTP1 was associated with increased risk of gastric cancer when compared with the Ile/Ile genotype (OR = 3.19, 95%CI = 1.84-5.56). Moreover, the Val allele of GSTP1 was associated with higher susceptibility to gastric cancer as compared with the Ile allele (OR = 1.52, 95%CI = 1.19-1.93). However, GSTM1 and GSTT1 polymorphisms did not affect the development of gastric cancer. In conclusion, our study indicated that GSTP1 Ile105Val, but not GSTM1 and GSTT1 polymorphisms, was associated with risk of gastric cancer.

Analysis of ADH1B Arg47His, ALDH2 Glu487Lys, and CYP4502E1 polymorphisms in gastric cancer risk and interaction with environmental factors.

Gastric cancer is the fourth commonly diagnosed cancer and the second most frequent cause of cancer death worldwide. Genetic variations in ADH1B and ALDH2 may alter the function and activity of the corresponding enzymes, leading to differences in acetaldehyde exposure between drinkers. Cytochrome P4502E1 (CYP4502E1) is a phase I enzyme that plays an important role in metabolizing nitrosamine compounds and the bioactivation of procarcinogens. During the period of July 2013 to July 2015, 246 patients and 274 controls were enrolled from the First Affiliated Hospital of Jinan University. In the codominant model, the AA genotype of ALDH2 Glu487Lys significantly elevated the risk of gastric cancer in comparison with the GG genotype of ALDH2 Glu487Lys. In the recessive model, the AA genotype of ALDH2 Glu487Lys significantly increased the risk of gastric cancer compared to the GG+GA genotype (OR = 2.34 95%CI = 1.02-5.70). We found in the codominant model that individuals harboring the C2/C2 genotype of CYP4502E1 had a higher risk of developing gastric cancer than those with the C1/C1 genotype. In addition, in the recessive model, we found that the C2/C2 genotype correlated with an elevated risk of gastric cancer in comparison with the C1/C1+C1/C2 genotype (OR = 4.90, 95%CI = 2.04-13.51). However, no significant relationship was measured between ADH1B Arg47His and gastric cancer risk. In summary, the results of our study indicate that ALDH2 Glu487Lys and CYP4502E1 polymorphisms could be risk factors for the development of gastric cancer in the Chinese population.

Radiation dose reduction in temporal bone CT with iterative reconstruction technique.

BACKGROUND AND PURPOSE: Iterative reconstruction of CT images is characterized by reduced image noise and may allow reduction in radiation exposure. We investigated the influence of an IRT technique on image quality and radiation dose savings when applied to temporal bone CT. MATERIALS AND METHODS: Based on the typical image quality level of adult subjects using routine radiation dose and FBP, an exsomatized cadaveric head with CNR characteristics closest to the level of clinical subjects was identified. Cadaver acquisitions were performed at multiple levels of tube current exposure. Reconstructions were performed using FBP and IRT (iDose), with multiple iDose levels applied for each acquisition. Transverse and coronal reformations of all reconstructions were evaluated subjectively and objectively. Phantom tests were performed to validate the protocol optimizations with iDose, specifically the spatial resolution relative to routine dose acquisitions. Finally, the results of protocol optimization with iDose were clinically validated in 50 patients. RESULTS: At the same radiation dose, the image CNR of iDose reconstructions was higher than that of FBP and progressively increased with higher iDose levels. The combination of 100 mAs/section and iDoseL5 was the lowest dose that met the requirements for diagnostic acceptability, with CNR slightly higher than our routine institution protocol of 200 mAs/section with FBP reconstruction. Spatial resolution characteristics were similar between FBP and iDose at all different strengths. The findings were consistent among the cadaver, phantom, and clinical acquisitions. CONCLUSIONS: The iDose IRT can help reduce radiation dose of temporal bone CT by 50% relative to routine institution protocols with FBP, while maintaining diagnostic image quality.

MR evaluation of sinonasal angiomatous polyp.

BACKGROUND AND PURPOSE: SAP is a rare lesion of the sinonasal cavity, which may be misdiagnosed as a benign or malignant neoplasm. The purpose of our study was to comprehensively evaluate the MR imaging features of SAP. MATERIALS AND METHODS: Forty patients with SAP confirmed pathologically were retrospectively reviewed. Of the 40 patients undergoing MR imaging, 39 had postcontrast T1WI; 30, DCE MR imaging; and 17, DWI. The image features assessed included the location, shape, margin, size, signal intensity, and enhancement pattern on DCE MR imaging and ADC maps. RESULTS: All 40 SAPs originated from the maxillary sinus, but the lesions frequently extended into the ipsilateral nasal cavity (38/40), toward the choana (19/40), and into the nasopharynx (8/40). The lesions demonstrated hypointensity on T1WI and heterogenous hyperintensity on T2WI. All 40 lesions showed a peripheral hypointense rim on T2WI. Postcontrast MR imaging revealed marked heterogeneous nodular and patchy enhancement. Progressive enhancement was found on DCE MR imaging in 30 cases. The TIC showed a steady enhancement pattern in 3 cases, a rapidly enhancing and slow washout pattern in 6 cases, and a rapidly enhancing and rapid washout pattern in 21 cases. On DWI, the mean ADC value was (1.40 ± 0.20) × 10(-3) mm(2)/s. CONCLUSIONS: Distinctive features of SAP on conventional MR imaging include internal heterogeneous hyperintensity and a peripheral hypointense rim on T2WI, as well as strong nodular and patchy enhancement on postcontrast MR images. The progressive enhancement on DCE MR imaging can also suggest the diagnosis.

Experimental study and optimization of scan parameters that influence radiation dose in temporal bone high-resolution multidetector row CT.

BACKGROUND AND PURPOSE: MDCT has some specific scan parameters that may systematically increase or decrease radiation dose to patients. This study explored the scan protocol parameters that impact radiation dose in temporal bone MDCT and determined the optimal scan parameters that balance radiation dose with diagnostic image quality. MATERIALS AND METHODS: Using exsomatized cadaveric heads, traditional axial scanning, and helical scanning were performed with different detector collimations. Helical scans of the same scan region were then acquired by using the determined optimal detector collimation and various tube voltages, whereas other scan parameters remained fixed. Next, the scans were repeated by using various tube current-time products by using the determined optimal tube voltage. Last, with fixed tube current-time product, the scans were repeated with various pitches. All thin-section, helically acquired scans were reformatted to axial and coronal images with respect to the relevant scanning baseline. In each of the image volumes, the mean and SD HU values in regions of interest were measured in the central section of the internal auditory canal, and CNR values were calculated. RESULTS: In agreement with theory, wider detector collimations such as 16 × 0.625 mm and 64 × 0.625 mm were associated with lower radiation doses than narrower collimations due to their lower overbeaming and higher geometric efficiency. In helical scanning, the detector collimation of 16 × 0.625 mm had higher image quality and the minimum DLP. Axial and coronal images acquired by using a 140-kVp tube voltage had significantly lower noise than scans acquired at 120 or 80 kVp with equivalent volume CT dose index. Diagnostic image quality was achieved when using a minimum tube current-time product of 120 mAs. Noise, CNR, and dose were jointly optimized with a pitch of 0.685. CONCLUSIONS: Temporal bone CT scanning parameters may be optimized by following a systematic procedure that allows for the optimization of diagnostic image quality and the minimization of radiation dose. One such procedure for a particular 64-section MDCT scanner has been presented.

Fibrous dysplasia-like appearance of the frontal process of the maxilla on CT: prevalence in North China.

The frontal process of the maxilla occasionally shows a localized FD-like appearance. The purpose of this study was to determine its prevalence and findings on CT. A retrospective study of 1000 consecutive paranasal sinus CT scans was preformed on outpatients without a history of trauma or previous surgery in our hospital during 6 months. CT images were interpreted independently by 2 experienced head and neck radiologists on a PACS system in a bone window setting. Of the 1000 patients (546 males; 454 females), 51 (5.1%,41 males and 10 females) had an FD-like appearance in the frontal process of the maxilla. There was a statistically significant difference between sexes (P < .001). Twenty-nine (56.9%) entities arose from the right frontal process and 22 (43.1%) from the left frontal process. These entities, with well-defined margins, were located at the base of the frontal process of the maxilla, appearing as an ovoid or triangular configuration on axial-plane CT and as a spindle or elliptic shape on the coronal plane. The mean maximal diameter was 9.8 mm (range, 3.6-16.1 mm). These entities exhibited a pagetoid appearance (type I) in 37 (72.5%), a ground-glass appearance (type II) in 8 (15.7%), and a cyst-like appearance (type III) in 6 (11.8%) patients on CT. The FD-like appearance of the frontal process of the maxilla is not rare and can be readily detected by CT.

Sphenoid sinus ectopic pituitary adenomas: CT and MRI findings.

Ectopic pituitary adenomas (EPAs) are rare lesions. The purpose of this study was to describe the CT and MRI features of sphenoid sinus EPAs. Eight patients with histology-proven EPAs in the sphenoid sinus, all of whom underwent CT and MRI, were reviewed retrospectively. The following imaging features were analysed: (i) size, (ii) margin, (iii) CT attenuation characteristics and (iv) MRI signal intensity. In addition, the involvement of adjacent structures and the time-intensity curve (TIC) of dynamic contrast-enhanced (DCE) MRI were analysed. All EPAs had well-defined margins and showed no relationship to the intrasellar pituitary gland. The mean size was 28 mm (range, 20-46 mm). On non-enhanced CT, the lesions appeared isodense to grey matter in 7 (88%) patients and hypodense in 1 (12%) patient. Only two patients underwent post-contrast CT, and they showed moderate enhancement. On T1 weighted images, EPAs appeared isointense in 6 (75%) patients and hypointense in 2 (25%). On T2 weighted images, the lesions appeared hyperintense in 2 (25%) patients and isointense in 6 (75%). EPAs showed mild to moderate heterogeneous contrast enhancement and exhibited a cribriform-like appearance. Two patients underwent DCE MRI; the TIC showed a rapidly enhancing and slow washout pattern. The following features were also seen: an empty sella, bone changes and involvement of the cavernous sinus (5 patients; 62.5%). In conclusion, a high index of suspicion for EPA and a familiarity with the imaging findings may help to diagnose this rare entity accurately.

Primary chordoma in the nasal cavity and nasopharynx: CT and MR imaging findings.

BACKGROUND AND PURPOSE: Primary chordoma in the nasal cavity and nasopharynx is an extremely rare tumor in the extraosseous axial skeleton. Unlike intracranial chordomas, lesions in these sites primarily present as a soft tissue mass without involvement of the skull base bone (clivus), so the preoperative diagnosis of the tumor is possibly difficult. Here, we reviewed the imaging features of 5 cases of chordomas in the nasal cavity and nasopharynx that resulted in successful diagnosis and differential diagnosis of this rare tumor. MATERIALS AND METHODS: We retrospectively studied 5 patients with histologically proven chordomas in the nasal cavity and nasopharynx. The lesion features of CT and MR imaging were reviewed, with emphasis on the size, shape, location, margin, calcification, CT attenuation characteristics, signal intensity, and degree of MR imaging enhancement. RESULTS: Expansible and lobular soft tissue masses were mainly present, with irregular intratumor calcification in all 5 cases on CT examination. MR imaging revealed a well-defined tumor with heterogeneous signal intensity in 4 patients, whereas homogeneous signal intensity in 1 patient was present on all pulse sequences. Four cases of nasopharyngeal mass showed mild to moderate heterogenous enhancement. Intratumor septa could be seen in 2 cases. CONCLUSIONS: Although no imaging features are pathognomonic, primary chordomas without skull base (clivus) bony changes in the nasal cavity and nasopharynx have some CT and MR imaging findings that are suggestive of diagnosis. The differential diagnosis of the soft tissue mass should be limited to these sites.

Leiomyoma of the sinonasal cavity: CT and MRI findings.

AIM: To determine the computed tomography (CT) and magnetic resonance imaging (MRI) features of leiomyoma of the sinonasal cavity. MATERIALS AND METHODS: Six patients with histology-proven leiomyomas in the sinonasal cavity were retrospectively reviewed. All six patients underwent CT and three patients also underwent MRI. The following imaging features were reviewed: size, margin, CT attenuation, MRI signal intensity, and lesion extent. In addition, the time-intensity curve (TIC) of dynamic contrast-enhanced (DCE) MRI and diffusion-weighted imaging (DWI) were analysed in two patients. RESULTS: All leiomyomas had well-defined margins. The mean size was 36 mm (range 20-51 mm). On unenhanced CT, the lesions appeared isodense to cerebral grey matter in four (67%) and slightly hypodense in two (33%) patients. Leiomyomas appeared isointense On T1-weighted imaging (WI) and slightly hyperintense on T2WI in three patients. The lesions showed moderate contrast enhancement. Two patients underwent DCE MRI, and the TIC showed a rapidly enhancing and slow washout pattern. The mean apparent diffusion coefficient (ADC) value were 1.66x10(-3) mm(2)/s and 1.78x10(-3) mm(2)/s for the two lesions, respectively. CONCLUSIONS: Well-defined, homogeneous, expansile masses without bony erosion are typical features of leiomyoma. Althrough rare, this entity should be included in the differential diagnosis of benign tumours in this region.

MR imaging features of primary mucosal melanoma of the eustachian tube: report of 2 cases.

We observed 2 cases of malignant melanoma arising from the eustachian tube with MR imaging. In this region, we explored further characteristics of primary mucosal melanoma. We discuss the value of using MR imaging to diagnose and treat patients with melanoma in the eustachian tube. In addition, we introduce the key points to differentiate melanoma from some common diseases in the region.

[The evaluation of cervical lymph node metastasis of laryngeal cancer using magnetic resonance imaging (MRI)].

OBJECTIVE: To assess the potential or limitation of MRI for demonstrating the pathological cervical lymphnodes. METHOD: A prospective diagnostic study on cervical lymphnode metastasis from laryngeal carcinoma was performed for 19 cases undergone neck dissection (5 cases undergone bilateral neck dissection, 24 specimens of neck dissection were collected in total). With pathological findings as the criterion, sensitivity and specificity and accuracy were calculated for palpation and MRI examination of all patients. RESULT: MRI had obviously higher sensitivity specificity and accuracy than palpation. Besides the changes in size and shape of the metastatic lymphnodes, the intensity of MRI inside the metastatic lymphnodes was showed as mixed hypo-isointensity in T1WI and hyper intensity in T2WI. CONCLUSION: MRI examination was accurate in detecting cervical lymphnode metastasis and could image occult lymphnodes which are inaccessible on palpation. Thus, MRI will probably play an important role in the evaluation of malignant lymphnode metastasis.