Dechun Zheng

Diffusion-weighted magnetic resonance imaging for early response assessment of chemoradiotherapy in patients with nasopharyngeal carcinoma

PURPOSE To prospectively evaluate the feasibility of diffusion-weighted magnetic resonance imaging (DWI) for monitoring early treatment response to chemoradiotherapy (CRT) of nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS Thirty-one patients with stage III and IV NPC were enrolled in this study from February 2012 to November 2012．T2-weighted and DWI sequences with diffusion factor of 0 and 800mm²/s were performed using a 3.0 T Philips Achieva TX scanner at baseline and 3 days, 20 days (after the first cycle of chemotherapy), 50 days (6 days after radiotherapy initiation) after neoadjuvant chemotherapy (NAC) initiation. The diameter of each primary lesion and target metastatic lymph node before and after the first cycle of NAC was measured and classified into stable disease (SD), partial response (PR) or completed response (CR) based on RECIST 1.1. The apparent diffusion coefficient (ADC) values and changes compared to baseline at each time point were compared between responders (CR and PR) and non-responders (SD). The rates of residual at the end of CRT were compared between these two groups. RESULTS A significant increase in ADC was observed at each stage of therapy (P=.001) in lesions of primary and metastatic. The ADC values (ADC), ADC changes (ΔADC) and percentage ADC changes (Δ%ADC) of day 20 in responders were significantly higher than in non-responders for both primary lesions (p=.005, p=.006, p=.008, respectively) and metastatic lymph nodes (p=.002, p=.002, p=.003). Non-responders showed a higher rate of residual for both primary lesions (p=.008) and metastatic lymph nodes (p=.024) than responders. CONCLUSIONS DW MR imaging allows for detecting early treatment response of NPC. Patients with high ADC values and large ADC increase early after NAC initiation tended to respond better to CRT. Thus, accessing the curative effect of NAC in advanced NPC provides the opportunity to adjust following CRT regimen.

Diffusion kurtosis imaging predicts neoadjuvant chemotherapy responses within 4 days in advanced nasopharyngeal carcinoma patients.

To explore the clinical value of diffusion kurtosis imaging (DKI) and monoexponential diffusion‐weighted imaging (DWI) for predicting early response to neoadjuvant chemotherapy (NAC) in patients with nasopharyngeal carcinoma (NPC).

Early response to chemoradiotherapy for nasopharyngeal carcinoma treatment: Value of dynamic contrast‐enhanced 3.0 T MRI

To prospectively evaluate the dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) value for predicting early nasopharyngeal carcinoma (NPC) chemoradiotherapy (CRT) response.

Dynamic contrast‐enhanced MRI of nasopharyngeal carcinoma: A preliminary study of the correlations between quantitative parameters and clinical stage

To evaluate the relationship between quantitative parameters of dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and clinical stage of nasopharyngeal carcinoma (NPC).

Unidimensional Measurement May Evaluate Target Lymph Nodal Response After Induction Chemotherapy for Nasopharyngeal Carcinoma.

AbstractThe aim of the study was to evaluate whether short axis and long axis on axial and coronal magnetic resonance imaging planes would reflect the tumor burden or alteration in size after induction chemotherapy in nasopharyngeal carcinoma.Patients with pathologically confirmed nasopharyngeal carcinoma (n = 37) with at least 1 positive cervical lymph node (axial short axis ≥15 mm) were consecutively enrolled in this prospective study. Lymph nodal measurements were performed along its short axis and long axis in both axial and coronal magnetic resonance imaging planes at diagnosis and after 2 cycles of induction chemotherapy. In addition, lymph nodal volumes were automatically calculated in 3D treatment-planning system, which were used as reference standard. Students t test or nonparametric Mann–Whitney U test was used to compare the continuous quantitative variables. Meanwhile, the &kgr; statistic and McNemars test were used to evaluate the degree of agreement and discordance in response categorization among different measurements.Axial short axis was significantly associated with volumes at diagnosis (P < 0.001). A good agreement (&kgr;=0.583) was found between axial short axis and volumetric criteria. However, the inconsistent lymph nodal shrinkage in 4 directions was observed. Axial short-axis shrinking was more rapid than the other 3 parameters. Interestingly, when utilizing the alternative planes for unidimensional measurements to assess tumor response, coronal short-axis showed the best concordance (&kgr;=0.792) to the volumes.Axial short axis may effectively reflect tumor burden or change in tumor size in the assessment of target lymph nodal response after induction chemotherapy for nasopharyngeal carcinoma. However, it should be noted that axial short axis may amplify the therapeutic response. In addition, the role of coronal short axis in the assessment of tumor response needs further evaluation.

The Utility of Diffusion-Weighted Magnetic Resonance Imaging for Discriminating and Early Detecting of Nasopharyngeal Carcinoma

Purpose: To study the utility of Diffusion-Weighted Magnetic Resonance Imaging to distinguish among Nasopharyngeal Carcinoma (NPC), lymphoma, tuberculosis and nasopharyngitis which originates in nasopharynx. Materials and Methods: Our hospital’s institutional review board approved this retrospective study. Forty-two patients with early stage NPC, sixteen with lymphoma, eleven with tuberculosis, and twenty-six with nasopharyngitis were included in this retrospectively study. All patients underwent both nasopharynx and skull base region MR Imaging and nasopharyngo-fiberscope biopsy in our hospital, and were finally diagnosed with histopathologically proven (n = 86) and clinical follow-up (n = 9). The Apparent diffusion coefficient (ADC) values were investigated by experienced radiologist, and averaged ADC value of per patient was compared in groups. Mean ADC values between two groups were compared by independent - samples T-test, and one-way Analysis of Variance was used to analyze mean ADC values among four groups. Results: Mean ADC values of malignant nasopharyngeal lesions (early stage NPC and lymphoma) and benign nasopharyngeal lesions (tuberculosis and nasopharyngitis) were (0.708 ± 0.158) and (0.913 ± 0.168) × 10-3 mm2/s respectively (t = 6.05, P < 0.01). Mean ADC values of nasopharyngeal lesions of early stage NPC, lymphoma, tuberculosis and nasopharyngitis were (0.753 ± 0.135), (0.590 ± 0.156), (0.855 ± 0.137), and (0.935 ± 0.179) × 10-3 mm2/s respectively (F = 18.89, P < 0.01), and post multiple comparisons showed that they were all Statistical significance on 0.05 level between NPC, lymphoma, tuberculosis and nasopharyngitis except subgroup tuberculosis and nasopharyngitis (p = 0.55); An ADC value lower than or equal to 0.828 × 10-3 mm2/s was used as threshold for nasopharyngeal malignancy, with a sensitivity 82.8% and specificity of 70.3%. When the same ADC value ≤ 0.828 × 10-3 mm2/s was used as threshold to differentiate early stage NPC from nasopharyngitis, sensitivity and specificity were 78.6% and 69.2% respectively. When an ADC value ≤ 0.681 × 10-3 mm2/s was used as threshold to differentiate lymphoma from early stage NPC, sensitivity and specificity were 81.3% and 71.4% respectively. Conclusion: MR DWI has a potential value in differentiating nasopharyngeal diseases.

Early diagnosis of radio-insensitive human nasopharyngeal carcinoma xenograft models by diffusion kurtosis imaging

OBJECTIVE To investigate the feasibility of DKI in early detection of radio-insensitive nasopharyngeal carcinoma (NPC) xenografts in nude mice. MATERIALS AND METHODS Seventy-two nude mice were implanted with CNE-1 (low radio-sensitive) and CNE-2 (high radio-sensitive) NPC cell lines, and their respective xenografts were obtained. Then, the NPC-bearing nude mice were exposed to different doses of fraction irradiation, which are divided into non-irradiated group (G0), 10Gy group (G1), 20Gy group (G2), 30Gy group (G3), 3rd (G4) and 5th (G5) days after the entire dose (30y) of irradiation. Subsequently, DKI was performed on each group. Tumor volumes, shrink rates, D and K parameters were measured by two experienced radiologists. Students t-test and receiver operating characteristic (ROC) curve analysis were conducted in this study. RESULTS The differences of volume shrinkage rate between CNE-1 and -2 were observed in G2 (P = 0.032), with the shrink rates of 5.954% and 27.716%, respectively. The D values were reduced at G1 (DG1, P = 0.001) and then increased gradually after irradiation. The K values were increased at G1 (KG1, P = 0.001) and then declined sharply in CNE-2 (P < 0.01), but not in CNE-1 xenografts (P > 0.05). The respective AUC values for DG1 and KG1 were 0.875 and 0.917, with 66.7% and 83.3% sensitivity and 100% specificity, at the cutoff values of 1.27 × 10-3 mm2/s for parameter D and 0.88 for parameter K. CONCLUSION DKI can be used for early detection of radio-insensitive NPC xenografts prior to morphological change, where DG1 and KG1 may be the most valuable indicators.

Establishment of prognostic factors in recurrent nasopharyngeal carcinoma patients who received salvage intensity-modulated radiotherapy: A meta-analysis

Local recurrence remains a major cause of therapeutic failure in patients with nasopharyngeal carcinoma (NPC) and the effective treatment of recurrent NPC (r-NPC) is still a challenge. Intensity-modulated radiotherapy (IMRT) is considered as a favorable technique in the management of r-NPC, especially for extensive lesions. However, local r-NPC is a highly heterogeneous disease and the survival outcome following salvage IMRT varies. Furthermore, due to varied samples and therapeutic protocols, no consensus has been reached in the establishment of prognostic values. Hence, we used Medline and Embase electronic databases to conducted a meta-analysis to generate the best estimation of the prognostic factors in local r-NPC following salvage IMRT. Finally, a total of 783 patients in seven studies were enrolled. Overall, the pooled HR for OS of recurrent T stage and recurrent tumor volume was 1.77 (95% CI = 1.15-2.39) and 2.12 (95% CI = 1.42-2.82), without any heterogeneity. In addition, despite a significant association was observed in the pooled HR of significant compliance for OS, however, significant heterogeneity was also observed (I2 = 76.6%, p = 0.039). Furthermore, no significant association was observed among the pooled HRs for OS in terms of age, gender, recurrent time interval, synchronous nodal recurrence, chemotherapy and total re-irradiation dose. Therefore, the present meta-analysis demonstrated that recurrent T stage and tumor volume may serve as the prognostic factors for OS in patients with r-NPC who received salvage IMRT. The other factors such as age, gender, and optimal re-irradiation dose warranted further investigation.

Diffusion kurtosis imaging of a human nasopharyngeal carcinoma xenograft model: Initial experience with pathological correlation

PURPOSE The aim of this study was to investigate the relationship between diffusion kurtosis imaging (DKI)-related parameters and pathological measures using human nasopharyngeal carcinoma (NPC) xenografts in a nude mouse model. MATERIALS AND METHODS Twenty-six BALB/c-nu nude mice were divided into two groups that were injected with two different nasopharyngeal squamous cell carcinoma cell lines (CNE1 and CNE2). DK magnetic resonance (MR) imaging was performed on a 3.0 Tesla MR scanner. DWI and DKI-related parameters, including apparent diffusion coefficient (ADC), mean diffusivity (MD) and mean kurtosis (MK) were measured. Mice were euthanatized when the maximum diameter of the primary tumor reached 1.5cm after MR scanning. Tumor tissues were then processed for hematoxylin and eosin staining. The pathological images were analyzed using a computer-aided pixel-wise clustering method to evaluate tumor cellular density, nuclei portion, cytoplasm portion, extracellular space portion, the ratio of nuclei to cytoplasm and the ratio of nuclei to extracellular space. The relationships between DWI and DKI-related parameters and pathological features were analyzed statistically. RESULTS The ADC and MD values of the CNE1 group (1.16±0.24×10-3mm2/s, 2.28±0.29×10-3mm2/s) was higher than that of the CNE2 group (0.82±0.14×10-3mm2/s, 1.53±0.24×10-3mm2/s, P<0.001), but the MK values between the two groups were not significantly different (CNE1: 0.55±0.14; CNE2: 0.47±0.23; P>0.05). A Pearson test showed that the ADC and MD values were significantly correlated with cellular density, nuclei portion, extracellular space portion and the ratio of nuclei to extracellular space (r=-0.861; -0.909, P<0.001; r=-0.487; 0.591, P<0.05; r=0.567; 0.625, P<0.05; r=-0.645; -0.745, P<0.001, respectively). The MK values were significantly correlated with nuclei portion, cytoplasm portion and the ratio of nuclei to cytoplasm (r=-0.475, P<0.05; r=0.665, P<0.001; r=-0.494, P<0.05, respectively). CONCLUSION The preliminary animal results suggest that DKI findings can provide valuable bio-information for NPC tissue characterization. DKI imaging might be utilized as a surrogate biomarker for the non-invasive assessment of tumor microstructures.

Integrating dynamic contrast-enhanced magnetic resonance imaging and diffusion kurtosis imaging for neoadjuvant chemotherapy assessment of nasopharyngeal carcinoma: Assessing Chemotherapy in NPC by MRI

Since neoadjuvant chemotherapy (NAC) has proven a benefit for locally advanced nasopharyngeal carcinoma (NPC), early response evaluation after chemotherapy is important to implement individualized therapy for NPC in the era of precision medicine.