Clinicopathological significance of unraveling mitochondrial pathway alterations in non-small-cell lung cancer.

Early detection, accurate monitoring, and therapeutics are major problems in non-small-cell lung cancer (NSCLC) patients. We identified genomic copy number variation of a unique panel of 40 mitochondria-targeted genes in NSCLCs (GEOGSE #29365). Validation of mRNA expression of these molecules revealed an altered panel of 34 genes in lung adenocarcinomas (LUAD) and 36 genes in lung squamous cell carcinomas (LUSC). In the LUAD subtype (n = 533), we identified 29 upregulated and 5 downregulated genes, while in the LUSC subtype (n = 502), a panel of 30 upregulated and 6 downregulated genes were discovered. The majority of these genes are associated with mitochondrial protein transport, ferroptosis, calcium signaling, metabolism, OXPHOS function, TCA cycle, apoptosis, and MARylation. Altered mRNA expression of SLC25A4, ACSF2, MACROD1, and GCAT was associated with poor survival of the NSCLC patients. Progressive loss of SLC25A4 protein expression was confirmed in NSCLC tissues (n = 59), predicting poor survival of the patients. Forced overexpression of SLC25A4 in two LUAD cell lines inhibited their growth, viability, and migration. A significant association of the altered mitochondrial pathway genes with LC subtype-specific classical molecular signatures was observed, implicating the existence of nuclear-mitochondrial cross-talks. Key alteration signatures shared between LUAD and LUSC subtypes including SLC25A4, ACSF2, MACROD1, MDH2, LONP1, MTHFD2, and CA5A could be helpful in developing new biomarkers and therapeutics.

Discriminating between benign and malignant salivary gland tumors using diffusion-weighted imaging and intravoxel incoherent motion at 3 Tesla.

PURPOSE: The purpose of this study was to retrospectively evaluate the diagnostic performances of diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) for discriminating between benign and malignant salivary gland tumors (SGTs). MATERIALS AND METHODS: Sixty-seven patients with 71 SGTs who underwent MRI examination at 3 Tesla were included. There were 34 men and 37 women with a mean age of 57 ± 17 (SD) years (age range: 20-90 years). SGTs included 21 malignant tumors (MTs) and 50 benign SGTs (33 pleomorphic adenomas [PAs] and 17 Warthin's tumors [WTs]). For each SGT, DWI and IVIM parameters, mean, skewness, and kurtosis of apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*) and perfusion volume fraction (f) were calculated and further compared between SGTs using univariable analysis. Areas under the curves (AUC) of receiver operating characteristic of significant parameters were compared using the Delong test. RESULTS: Significant differences in ADCmean, Dmean and D*mean were found between SGTs (P < 0.001). The highest AUC values were obtained for ADCmean (0.949) for identifying PAs and D*mean (0.985) for identifying WTs and skewness and kurtosis did not outperform mean. To discriminate benign from malignant SGTs with thresholds set to maximize Youden index, IVIM and DWI produced accuracies of 85.9% (61/71; 95% CI: 75.6-93.0) and 77.5% (55/71; 95% CI: 66.0-86.5) but misdiagnosed MTs as benign in 28.6% (6/21) and 61.9% (13/21) of SGTs, respectively. After maximizing specificity to 100% for benign SGTs, the accuracies of IVIM and DWI decreased to 76.1% (54/71; 95% CI: 64.5-85.4) and 64.8% (46/71; 95% CI: 52.5-75.8) but no MTs were misdiagnosed as benign. IVIM and DWI correctly diagnosed 66.0% (33/50) and 50.0% (25/50) of benign SGTs and 46.5% (33/71) and 35.2% (25/71) of all SGTs, respectively. CONCLUSION: IVIM is more accurate than DWI for discriminating between benign and malignant SGTs because of its advantage in detecting WTs. Thresholds set by maximizing specificity for benign SGTs may be advantageous in a clinical setting.

Imaging of head and neck mucosa-associated lymphoid tissue lymphoma (MALToma).

Marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALToma) arises in extranodal sites in the head and neck. Chronic inflammatory, infectious or autoimmune conditions are implicated in its pathogenesis. Within the head and neck, MALToma is often multifocal and indolent and the imaging appearances may be mistaken for non-malignant disease in the head and neck. The aim of this article is to illustrate the varied radiological and clinical features of MALToma in the head and neck, an awareness of which is needed for timely and correct diagnosis to guide subsequent disease management.

Multi-drug Resistant and Extended Spectrum ß-lactamase Producing Salmonella Species Isolated from Fresh Chicken Liver Samples.

Background Emergence of antibiotic resistance among microbes contaminating the fresh meat products is a global public health concern as they can be easily transmitted to humans through their consumption and contact. Objective The current study was conducted to determine the distribution of antimicrobial resistance among Salmonella species isolated from fresh chicken liver samples with special emphasis on extended spectrum beta-lactamase (ESBL) production. Method A total of 200 fresh chicken liver samples were cultivated for the isolation of Salmonella and further subcultivated to detect extended spectrum beta-lactamase production among them. Antimicrobial susceptibility testing (AST) was done by disk diffusion method using a panel of 7 antimicrobials. Result Out of 200 samples analyzed, 61 (30.5%) samples harbored Salmonella species out of which 15 (7.5%) samples showed the presence of Salmonella Typhi. A significant association was noted in the incidence of Salmonella with various factors pertaining to the butchers, such as age, sex, literacy rate, practices of washing knives and chopping board, wearing aprons and gloves and type of water used (p < 0.05). Salmonella isolates were highly sensitive to amikacin (82.0%) and least sensitive to tetracycline (3.3%). All the isolates were resistant to colistin. Sixty (98.4%) isolates were identified as multi-drug resistant (MDR). The total number of extended spectrum betalactamase producers reported among Salmonella isolates was 29 (47.5%). Conclusion The results indicate that the fresh chicken liver samples sold in Bharatpur Metropolis are reservoirs of multi-drug resistant Salmonella, including extended spectrum betalactamase producers, that could potentially be transmitted to the humans by direct contact or through inadequate cooking.

Amide proton transfer MRI detects early changes in nasopharyngeal carcinoma: providing a potential imaging marker for treatment response.

PURPOSE: To determine if treatment of nasopharyngeal carcinoma (NPC) induces early changes in amide proton transfer-weighted (APTw) magnetic resonance imaging (MRI), and to perform a preliminary evaluation of APTw imaging in response assessment. METHODS: Sixteen patients with NPC planned for treatment with radiotherapy and/or chemotherapy underwent APTw imaging of the primary tumour pre-treatment and 2-week intra-treatment. Difference in pre- and intra-treatment APT mean (APTmean) was compared using the Wilcoxon signed rank test. Differences in APTmean and percentage change (%Δ) in APTmean were compared between responders and non-responders based on the outcome at 6 months, using the Mann-Whitney U test. RESULTS: APTmean decreased in 9/16 (56.3%) and increased in 7/16 (43.7%) with no significant difference between the pre- and intra-treatment APT values for the whole group (p > 0.05). NPC showed response in 11/16 (68.8%) and non-response in 5/11 (31.2%). There were significant differences between the %Δ of responders and non-responders for APTmean (p = 0.01). Responders showed %Δ decrease in APTmean of - 23.12% while non-responders showed a %Δ increase in APTmean of + 102.28%. CONCLUSION: APT value changes can be detected in early intra-treatment. Intra-treatment %Δ APTmean shows potential in predicting short-term outcome.

Adenosine deaminase activity in type 2 diabetes mellitus: does it have any role?

BACKGROUND: Diabetes mellitus is a group of metabolic disorders of carbohydrate metabolism in which glucose is underused, producing hyperglycemia. Diabetic patients are prone to opportunistic infection, thus serum ADA levels in these patients is very important as a screening test for Tuberculosis and autoimmune diseases. Thus, the present study was conducted to estimate the Serum ADA activity, glycated Haemoglobin (HbA1c), fasting and postprandial glucose level in patients with T2DM and to correlate the serum level of ADA with glycated Hemoglobin (HbA1c), fasting and postprandial glucose level in T2DM. METHODS: This is a Hospital based cross-sectional study done in BPKIHs, Dharan, Nepal. 204 diagnosed patients (102 males and 102 females) with T2DM and 102 healthy controls were enrolled in the study. Diabetic patients were categorized into Uncontrolled and Controlled Diabetes on the basis of HbA1C; HbA1c > 7% = Uncontrolled Diabetes, HbA1c < 7% = Controlled Diabetes. RESULTS: Serum ADA levels (U/L) was significantly raised in Uncontrolled Diabetic patients (49.24 ± 16.89) compared to controlled population (35.74 ± 16.78) and healthy controls (10.55 ± 2.20), p value < 0.001. A significant positive correlation was obtained between Serum ADA and HbA1c, Fasting Plasma Glucose and Post-prandial Glucose respectively. CONCLUSION: There is a significant increase in Serum ADA activity in DM with increase in HbA1c levels which may play an important role in predicting the glycemic and immunological status in these patients.

Head and Neck Tumors: Amide Proton Transfer MRI.

Purpose To evaluate the utility of amide proton transfer (APT) imaging in the characterization of head and neck tumors. Materials and Methods This retrospective study of APT imaging included 117 patients with 70 nasopharyngeal undifferentiated carcinomas (NUCs), 26 squamous cell carcinomas (SCCs), eight non-Hodgkin lymphomas (NHLs), and 13 benign salivary gland tumors (BSGTs). Normal tissues were examined in 25 patients. The APT means of malignant tumors, normal tissues, and benign tumors were calculated and compared with the Student t test and analysis of variance. The added value of the mean APT to the mean apparent diffusion coefficient (ADC) for differentiating malignant and benign tumors was evaluated by using receiver operating characteristic analysis and integrated discrimination index. Results The mean APT of malignant tumors (2.40% ± 0.97 [standard deviation]) was significantly higher than that of brain tissue (1.13% ± 0.43), muscle tissue (0.23% ± 0.73), and benign tumors (1.32% ± 1.20) (P < .001). There were no differences between malignant groups (NUC, 2.37% ± 0.90; SCC, 2.41% ± 1.16; NHL, 2.65% ± 0.89; P = .45 to P = .86). The mean ADC of malignant tumors ([0.85 ± 0.17] × 10-3 mm2/sec) was significantly lower than that of benign tumors ([1.46 ± 0.47] × 10-3 mm2/sec) (P = .001). Adding APT to ADC increased the area under the curve from 0.87 to 0.96, with an integrated discrimination index of 7.6% (P = .13). Conclusion These preliminary data demonstrate differences in amide proton transfer (APT) mean of malignant tumors, normal tissues, and benign tumors, although APT mean could not be used to differentiate between malignant tumor groups. APT imaging has the potential to be of added value to apparent diffusion coefficient in differentiating malignant from benign tumors.

Nasopharyngeal carcinoma: relationship between invasion of the prevertebral space and distant metastases.

PURPOSE: To identify primary sites of nasopharyngeal carcinoma (NPC) invasion on the staging head and neck magnetic resonance imaging (MRI) that correlate with distant metastases (DM). MATERIALS AND METHODS: Staging head and neck MRI examinations of 579 NPC patients were assessed for primary tumour invasion into 16 individual sites, primary stage (T) and nodal stage (N). Results were correlated with distant metastasis-free survival (DMFS) using the Cox regression, and the diagnostic performance of significant independent markers for DM was calculated. In addition, sites of primary tumour invasion were correlated also with involvement of the first echelon of ipsilateral nodes (FEN+) using logistic regression. RESULTS: Distant metastases were present in 128/579 NPC patients (22.1%) after intensity-modulated radiotherapy (IMRT)/chemo-IMRT and 5-year DMFS was 78.8%. Prevertebral space invasion (PVS+) and N stage, but not T stage, were independent prognostic markers of DMFS (p = 0.016, < 0.001, and 0.433, respectively). Compared to stage N3, PVS invasion had a higher sensitivity (28.1 vs. 68.8%), but lower specificity (90.5 vs. 47.4%) and accuracy (76.7 vs. 48.9%) for correlating patients with DM. PVS invasion, together with parapharyngeal fat space invasion (PPFS+), was also an independent predictive marker of FEN+. CONCLUSION: PVS was the only site of primary tumour invasion that independently correlated with DM, and together with PPFS + was an independent prognostic marker of FEN+, but the low specificity and accuracy of PVS invasion limits its use as a prognostic marker of DM.

Prediction of distant metastases from nasopharyngeal carcinoma: Improved diagnostic performance of MRI using nodal volume in N1 and N2 stage disease.

PURPOSE: To determine if the magnetic resonance imaging (MRI) of the head and neck can predict distant metastases (DM) from nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: MRI examinations of 763 NPC patients were assessed for primary tumour stage (T), nodal stage (N), primary tumour volume (PTV) and total nodal volume (NV). The association between MRI and clinical parameters were examined in DM+ and DM- patients using logistic regression and for distant metastases free survival (DMFS) using cox regression. Optimum thresholds were assessed by receiver-operating characteristics analysis, and positive predictive value (PPV) and odds ratio (OR) calculated. RESULTS: Distant metastases were present in 181/763 NPC patients (23.7%). Higher N stage and NV were the independent predictors of DM (p<0.001 and 0.018 respectively) and poor DMFS (p=0.001 and 0.030 respectively). Addition of NV (threshold≥32.8cm3) to the N stage improved the PPVs and ORs for DM in stage N1 (from 18.9% to 31.8% and 5.613 to 11.133 respectively) and stage N2 (from 40.4% to 60.8% and 16.189 to 36.979 respectively) but not in stage N3 (68.3% to 68.6% and 51.385 to 52.052 respectively). CONCLUSION: MRI N stage and NV were independent predictors of DM and DMFS. The addition of NV in NPC patients with bulky N1 and N2 disease improved the ability of MRI to predict DM.

Acute diffuse thyroid swelling: A rare complication of fine-needle aspiration.

We present a case illustrating the rare complication of acute generalized thyroid swelling shortly after sonographic-guided fine needle aspiration of a thyroid nodule. Ultrasound revealed the presence of characteristic linear hypoechoic avascular areas interspersed throughout the gland suggestive of edema. The patient was treated conservatively, with near complete normalization of the thyroid within 24 hours. Recognition of this potential complication is important, as the rapid onset of diffuse thyroid enlargement is often alarming but typically has a transient and self-limiting course. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:426-429, 2017.

Diffusion-weighted imaging of nasopharyngeal carcinoma to predict distant metastases.

Our study aimed to identify diffusion-weighted imaging (DWI) parameters obtained from primary nasopharyngeal carcinoma (NPC) at initial presentation, that can predict patients at risk of distant metastases. One hundred and sixty-four patients underwent pretreatment magnetic resonance imaging and DWI. The apparent diffusion coefficient (ADC)mean, ADCskewness, and ADCkurtosis were obtained by histogram analysis. Univariate and multivariate analyses of these ADC parameters together with primary volume (PV), nodal volume (NV), T stage, N stage and presence of locoregional relapse (LRR) were compared between patients with distant metastases (DM+) and patients without distant metastases (DM-) at 5 years using logistic regression. Twenty-eight out of 164 patients (17.1 %) were DM+ (2.5-60 months) and 136/164 patients were DM- (61.2-119.4 months). Compared to DM- patients, the primary tumour of DM+ patients showed significantly lower ADCskewness (ADC values with the greatest frequency were higher) (p = 0.041), and higher PV (p = 0.022), NV (p < 0.01), T stage (p = 0.023), N stage (p < 0.01) and LRR (p < 0.01). On multivariate analysis the ADCskewness was no longer significant (p = 0.120) and only NV and LRR were independent predictors for DM+ (p = 0.023 and 0.021, respectively). DWI showed that compared to DM- patients, DM+ patients had a significantly lower primary tumour ADCskewness, but at initial presentation NV was the only independent predictor of DM.

MRI of diffuse large B-cell non-Hodgkin's lymphoma of the head and neck: comparison of Waldeyer's ring and sinonasal lymphoma.

To document the magnetic resonance imaging (MRI) features of diffuse large B-cell lymphoma (DLBCL) in Waldeyer's ring (WR) and the sinonasal (SN) region, and to identify any differences between lymphatic and extra-lymphatic DLBCLs, and predictors of disease beyond the neck. Primary, nodal, and multifocal sites on head and neck MRI were compared between 31 WR and 15 SN DLBCL, and between 27 patients with disease confined to the head and neck and 16 patients with disease beyond the neck, using logistic regression. Compared to SN, WR DLBCLs had significantly smaller primary tumour volumes (p = 0.009), less deep invasion (p = 0.001), and more nodal disease (p = 0.016). Tumour site (WR vs. SN) was an independent predictor of deep invasion (p = 0.007). Nodal and multifocal diseases were predictors of disease beyond the neck (p = 0.027 and 0.011, respectively). Lymphatic WR DLBCLs were less locally aggressive but had greater propensity to nodal spread than extra-lymphatic SN DLBCLs. Nodal and multifocal diseases predicted disease beyond the neck.

Comparative evaluation of fracture resistance of glass fiber reinforced, carbon, and quartz post in endodontically treated teeth: An in-vitro study.

AIM AND OBJECTIVES: Use of posts improves the physical properties of endodontically-treated teeth. Different post types are developed such as metal, custom-made, carbon, and quartz. The present study was conducted to evaluate the fracture resistance of glass fiber-reinforced, carbon, and quartz post in endodontically-treated teeth. MATERIALS AND METHODS: Forty extracted human maxillary incisor teeth were decoronated and endodontically treated and equally divided into 4 groups; control, glass fiber-reinforced, carbon, and quartz posts. No post was used in the control group. Post space was prepared and cemented with different posts and subjected to universal testing machine to check fracture resistance. The data were statistically analyzed using t-test and analysis of variance to compare the mean difference between groups (SPSS version 20, IBM). RESULTS: Quartz type of endodontic post showed good fracture resistance compared to carbon and resin-reinforced post. Least resistance was observed in the control group without post. CONCLUSION: Quartz, carbon, and glass fiber-reinforced posts show good resistance to fracture, and hence can be used in endodontically-treated teeth to enhance their strength.

Cervical nodal metastases from head and neck squamous cell carcinoma: MRI criteria for treatment assessment.

BACKGROUND: The purpose of this study was to assess MRI criteria for detecting residual malignant head and neck squamous cell carcinoma (HNSCC) nodes after chemoradiotherapy (CRT). METHODS: One hundred and six metastatic nodes were assessed 6 weeks posttreatment by MRI for necrosis, extranodal neoplastic spread (ENS), size, and percentage of size change. Size measurements were reanalyzed after dividing posttreatment nodes into "discrete solid," "discrete necrotic," and "indiscrete" groups. Results were correlated with nodal response at 2 years. RESULTS: Eighty-three residual nodes were benign and 23 were malignant. Significant predictors of outcome were percentage of change in solid volume (total-necrotic volume; p = .0002) for all posttreatment nodes and percentage of change in total volume for "discrete solid" posttreatment nodes (p = .0003), the latter showing a ≤78% reduction of predicted residual malignant nodes with a negative predictive value (NPV) of 98.2% and positive predictive value (PPV) of 60%. Necrosis, ENS, and size of "discrete necrotic" and "indiscrete" nodes were not significant criteria. CONCLUSION: Necrosis and ENS were inaccurate criteria for residual malignant nodes and hindered the accuracy of size measurements. © 2016 Wiley Periodicals, Inc. Head Neck 38: E1598-E1604, 2016.

CT pre-operative planning of a new semi-implantable bone conduction hearing device.

PURPOSE: Accommodating a novel semi-implantable bone conduction hearing device within the temporal bone presents challenges for surgical planning. This study describes the utility of CT in pre-operative assessment of such an implant. METHODS: Retrospective review of pre-operative CT, clinical and surgical records of 16 adults considered for device implantation. Radiological suitability was assessed on CT using 3D simulation software. Antero-posterior (AP) dimensions of the mastoid bone and minimum skull thickness were measured. CT planning results were correlated with operative records. RESULTS: Eight and five candidates were suitable for device placement in the transmastoid and retrosigmoid positions, respectively, and three were radiologically unsuitable. The mean AP diameter of the mastoid cavity was 14.6 mm for the transmastoid group and 4.6 mm for the retrosigmoid group (p < 0.05). Contracted mastoid and/or prior surgery were predisposing factors for unsuitability. Four transmastoid and five retrosigmoid positions required sigmoid sinus/dural depression and/or use of lifts due to insufficient bone capacity. CONCLUSION: A high proportion of patients being considered have contracted or operated mastoids, which reduces the feasibility of the transmastoid approach. This finding combined with the complex temporal bone geometry illustrates the importance of careful CT evaluation using 3D software for precise device simulation. KEY POINTS: • Preoperative temporal bone CT is essential for determining Bonebridge device suitability. • Mastoid under-pneumatisation and prior mastoidectomy predict a retrosigmoid Bonebridge position. • 3D simulation software is recommended for precise device positioning.

Contemporary solutions for patients with microtia and congenital aural atresia - Hong Kong experience.

Managing microtia patients is always a challenge. Multidisciplinary approach, good family support, well established doctor-patient relationship and well organised patient-support groups are the essential elements for success. With the advancement of implantable hearing devices, more options will be available for the microtia patients. Otologists play a leading role in the whole management process. They not only provide proper guidance to the patients in choosing the correct path of the treatment, but also play a key role in organising and maintaining a cost-effective multidisciplinary rehabilitation team for the microtia patients.

DCE-MRI for Pre-Treatment Prediction and Post-Treatment Assessment of Treatment Response in Sites of Squamous Cell Carcinoma in the Head and Neck.

BACKGROUND AND PURPOSE: It is important to identify patients with head and neck squamous cell carcinoma (SCC) who fail to respond to chemoradiotherapy so that they can undergo post-treatment salvage surgery while the disease is still operable. This study aimed to determine the diagnostic performance of dynamic contrast enhanced (DCE)-MRI using a pharmacokinetic model for pre-treatment predictive imaging, as well as post-treatment diagnosis, of residual SCC at primary and nodal sites in the head and neck. MATERIAL AND METHODS: Forty-nine patients with 83 SCC sites (primary and/or nodal) underwent pre-treatment DCE-MRI, and 43 patients underwent post-treatment DCE-MRI, of which 33 SCC sites had a residual mass amenable to analysis. Pre-treatment, post-treatment and % change in the mean Ktrans, kep, ve and AUGC were obtained from SCC sites. Logistic regression was used to correlate DCE parameters at each SCC site with treatment response at the same site, based on clinical outcome at that site at a minimum of two years. RESULTS: None of the pre-treatment DCE-MRI parameters showed significant correlations with SCC site failure (SF) (29/83 sites) or site control (SC) (54/83 sites). Post-treatment residual masses with SF (14/33) had significantly higher kep (p = 0.05), higher AUGC (p = 0.02), and lower % reduction in AUGC (p = 0.02), than residual masses with SC (19/33), with the % change in AUGC remaining significant on multivariate analysis. CONCLUSION: Pre-treatment DCE-MRI did not predict which SCC sites would fail treatment, but post-treatment DCE-MRI showed potential for identifying residual masses that had failed treatment.

Thyroid nodule ultrasound: technical advances and future horizons.

UNLABELLED: Thyroid nodules are extremely common and the vast majority are non-malignant; therefore the accurate discrimination of a benign lesion from malignancy is challenging. Ultrasound (US) characterisation has become the key component of many thyroid nodule guidelines and is primarily based on the detection of key features by high-resolution US. The thyroid imager should be familiar with the strengths and limitations of this modality and understand the technical factors that create and alter the imaging characteristics. Specific advances in high-resolution US are discussed with reference to individual features of thyroid cancer and benign disease. Potential roles for three-dimensional thyroid ultrasound and computer-aided diagnosis are also considered. The second section provides an overview of current evidence regarding thyroid ultrasound elastography (USE). USE is a novel imaging technique that quantifies tissue elasticity (stiffness) non-invasively and has potential utility because cancers cause tissue stiffening. In recent years, there has been much research into the value of thyroid USE for distinguishing benign and malignant nodules. Preliminary findings from multiple pilot studies and meta-analyses are promising and suggest that USE can augment the anatomical detail provided by high-resolution US. However, a definite role remains controversial and is discussed. TEACHING POINTS: • High-resolution US characterises thyroid nodules by demonstration of specific anatomical features • Technical advances heavily influence the key US features of thyroid nodules • Most papillary carcinomas appear stiffer than benign thyroid nodules on US elastography (USE) • Thyroid USE is controversial because of variation in the reported accuracies for malignancy • Combined grey-scale US/USE may lower the FNAC rate in benign nodules.

Amide proton transfer-weighted imaging of the head and neck at 3 T: a feasibility study on healthy human subjects and patients with head and neck cancer.

The aim of this study was to explore the feasibility and repeatability of amide proton transfer-weighted (APTw) MRI for the head and neck on clinical MRI scanners. Six healthy volunteers and four patients with head and neck tumors underwent APTw MRI scanning at 3 T. The APTw signal was quantified by the asymmetric magnetization transfer ratio (MTRasym) at 3.5 ppm. Z spectra of normal tissues in the head and neck (masseter muscle, parotid glands, submandibular glands and thyroid glands) were analyzed in healthy volunteers. Inter-scan repeatability of APTw MRI was evaluated in six healthy volunteers. Z spectra of patients with head and neck tumors were produced and APTw signals in these tumors were analyzed. APTw MRI scanning was successful for all 10 subjects. The parotid glands showed the highest APTw signal (~7.6% average), whereas the APTw signals in other tissues were relatively moderate. The repeatability of APTw signals from the masseter muscle, parotid gland, submandibular gland and thyroid gland of healthy volunteers was established. Four head and neck tumors showed positive mean APTw ranging from 1.2% to 3.2%, distinguishable from surrounding normal tissues. APTw MRI was feasible for use in the head and neck regions at 3 T. The preliminary results on patients with head and neck tumors indicated the potential of APTw MRI for clinical applications.

Non-Gaussian analysis of diffusion weighted imaging in head and neck at 3T: a pilot study in patients with nasopharyngeal carcinoma.

PURPOSE: To technically investigate the non-Gaussian diffusion of head and neck diffusion weighted imaging (DWI) at 3 Tesla and compare advanced non-Gaussian diffusion models, including diffusion kurtosis imaging (DKI), stretched-exponential model (SEM), intravoxel incoherent motion (IVIM) and statistical model in the patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: After ethics approval was granted, 16 patients with NPC were examined using DWI performed at 3T employing an extended b-value range from 0 to 1500 s/mm(2). DWI signals were fitted to the mono-exponential and non-Gaussian diffusion models on primary tumor, metastatic node, spinal cord and muscle. Non-Gaussian parameter maps were generated and compared to apparent diffusion coefficient (ADC) maps in NPC. RESULTS: Diffusion in NPC exhibited non-Gaussian behavior at the extended b-value range. Non-Gaussian models achieved significantly better fitting of DWI signal than the mono-exponential model. Non-Gaussian diffusion coefficients were substantially different from mono-exponential ADC both in magnitude and histogram distribution. CONCLUSION: Non-Gaussian diffusivity in head and neck tissues and NPC lesions could be assessed by using non-Gaussian diffusion models. Non-Gaussian DWI analysis may reveal additional tissue properties beyond ADC and holds potentials to be used as a complementary tool for NPC characterization.