Potential value of non-echo-planar diffusion-weighted imaging of the nasopharynx: a primary study for differential diagnosis between recurrent nasopharyngeal carcinoma and post-chemoradiation fibrosis

Surveillance tools for detection of recurrent nasopharyngeal carcinoma: An evidence-based review and recommendations

Objective

Nasopharyngeal carcinomas (NPC) are tumors arising from epithelium of the nasopharynx. The 5-year survival rate of primary NPC is 80% with significant risks of recurrence. The objective here is to provide an evidence-based systemic review of the diagnostic value of different modalities in detecting local, regional, and distal recurrent NPC, as well as the associated costs with these modalities.

Methods

MEDLINE, EMBASE, and the Cochrane review database were queried. Two hundred and twenty-three abstracts were generated using the inclusion criteria: patients >18 years of age; histopathological reference standard; and modalities pertaining to imaging or microbiology.

Results

Twenty-four manuscripts fulfilled the inclusion criteria and 5 surveillance tools identified: endoscopy, MR, FDG-PET, Tc-99m MIBI and ²⁰¹TI SPECT, and EBV DNA.

Conclusions

For local surveillance, endoscopy is the gold standard recommendation, with increased efficacy if Narrow Band Imaging or contact endoscopy are utilized. MRI and FDG-PET is also recommended to help with local to distal spread; however, Tc-99m MIBI and ²⁰¹TI SPECT are options as well. EBV DNA is recommended as a cheap and accessible adjunct surveillance tool if an available as an option.

ADC for Differentiation between Posttreatment Changes and Recurrence in Head and Neck Cancer: A Systematic Review and Meta-analysis

BACKGROUND

Previous studies reported that the ADC values of recurrent head and neck cancer lesions are lower than those of posttreatment changes, however, the utility of ADC to differentiate them has not been definitively summarized and established.

PURPOSE

Our aim was to evaluate the diagnostic benefit of ADC calculated from diffusion-weighted imaging in differentiating recurrent lesions from posttreatment changes in head and neck cancer.

DATA SOURCES

MEDLINE, Scopus, and EMBASE data bases were searched for studies.

STUDY SELECTION

The review identified 6 prospective studies with a total of 365 patients (402 lesions) who were eligible for the meta-analysis.

DATA ANALYSIS

Forest plots were used to assess the mean difference in ADC values. Heterogeneity among the studies was evaluated using the Cochrane Q test and the I² statistic.

DATA SYNTHESIS

Among included studies, the overall mean of ADC values of recurrent lesions was 1.03 × 10^-3mm²/s and that of the posttreatment changes was 1.51 × 10^-3mm²/s. The ADC value of recurrence was significantly less than that of posttreatment changes in head and neck cancer (pooled mean difference: -0.45; 95% CI, -0.59-0.32, P < .0001) with heterogeneity among studies. The threshold of ADC values between recurrent lesions and posttreatment changes was suggested to be 1.10 × 10^-3mm²/s.

LIMITATIONS

Given the heterogeneity of the data of the study, the conclusions should be interpreted with caution.

CONCLUSIONS

The ADC values in recurrent head and neck cancers are lower than those of posttreatment changes, and the threshold of ADC values between them was suggested.

Diffusion-weighted MRI for predicting treatment response in patients with nasopharyngeal carcinoma: a systematic review and meta-analysis

Early prediction of treatment response in nasopharyngeal carcinoma is clinically relevant for optimizing treatment strategies. This meta-analysis was performed to evaluate whether apparent diffusion coefficient (ADC) from diffusion-weighted imaging (DWI) can predict treatment response of patients with nasopharyngeal carcinoma. A systematic search of PubMed-MEDLINE and Embase was performed to identify relevant original articles until July 22, 2021. We included studies which performed DWI for predicting locoregional treatment response in nasopharyngeal carcinoma treated with neoadjuvant chemotherapy, definitive chemoradiation, or radiation therapy. Hazard ratios were meta-analytically pooled using a random-effects model for the pooled estimates of overall survival, local relapse-free survival, distant metastasis-free survival and their 95% CIs. ADC showed a pooled sensitivity of 87% (95% CI 72–94%) and specificity of 70% (95% CI 56–80%) for predicting treatment response. Significant between-study heterogeneity was observed for both pooled sensitivity (I² = 68.5%) and specificity (I² = 92.2%) (P < 0.01). The pooled hazard ratios of low pretreatment ADC for assessing overall survival, local relapse-free survival, and distant metastasis-free survival were 1.42 (95% CI 1.09–1.85), 2.31 (95% CI 1.42–3.74), and 1.35 (95% CI 1.05–1.74), respectively. In patients with nasopharyngeal carcinoma, pretreatment ADC demonstrated good predictive performance for treatment response.

Detection and staging of recurrent or metastatic nasopharyngeal carcinoma in the era of FDG PET/MR

PURPOSE

The aim of this pilot study was to evaluate the accuracy of 18 fluorodeoxyglucose (FDG) PET/MR imaging in detection and staging of recurrent or metastatic NPC.

PATIENTS AND METHODS

The PET/MR scans of 60 patients with clinically diagnosed recurrent or metastatic NPC between April 2017 and November 2019 were included in this study. Findings were evaluated according to the eighth edition of the American Joint Committee on Cancer staging system. Final diagnosis was confirmed at biopsy or imaging follow-up for at least 6 months.

RESULTS

Of the 60 patients, 25, 26 and 42 had developed local lesions, regional nodal metastases and distant metastases, respectively. The overall accuracy of PET/MR imaging for staging of recurrent or metastatic NPC was 88.3%.

CONCLUSIONS

For recurrent or metastatic NPC, 18 FDG PET/MRI might serve as a single-step staging modality.

The clinical features, recurrence risks and surgical strategies of bone invasive pituitary adenomas

OBJECTIVE

Bone invasive pituitary adenomas (BIPAs) show obvious malignant behaviour. The aim of this study was to analyse the clinical features, prognosis, recurrence risks and surgical strategies of BIPAs.

PATIENTS AND METHODS

Clinical charts and radiological information were reviewed retrospectively in 107 consecutive cases of BIPAs. Transnasal endoscopic surgery was adopted with the goal of removing tumours. Scheduled follow-up was performed.

RESULTS

Clinical variable analyses revealed a significant correlation between bone invasive range and sex, tumour volume and tumour regrowth. Gross total resection, subtotal resection and partial resection were achieved in 26 cases (24.3 %), 28 cases (26.2 %) and 53 cases (49.5 %), respectively. There was a significant correlation between nongross total resection and female sex, young age, large tumour volume, bone invasive range, tumour regrowth and functional pituitary adenomas in BIPAs. The tumour regrowth rates at 3 years, 5 years and 10 years were 45.3 %, 76.3 % and 97.5 %, respectively. Kaplan-Meier curve analysis showed that tumour volume, bone invasion range, age, recurrent tumours and tumour resection degree were associated with BIPA regrowth. Multivariate analysis showed that tumour resection degree, bone invasive range, and tumour diameter were independent risk factors for BIPA regrowth.

CONCLUSION

BIPAs have the characteristics of high surgical risk, low GTR rate and high recurrence rate. There was a significant correlation between bone invasive range and sex, tumour volume and tumour regrowth in BIPAs. Bone invasive range is an independent risk factor for BIPA regrowth.

Diffusion-weighted magnetic resonance imaging (DWMRI) of head and neck squamous cell carcinoma: could it be an imaging biomarker for prediction of response to chemoradiation therapy

Background

Chemoradiation therapy (CRT) has become a primary definitive treatment modality for head and neck squamous cell carcinoma (HNSCC); however, not all patients respond completely to treatment. Ability to identify those patients, who would not achieve complete response, before or early during the course of CRT will allow treatment modifications to improve outcome and overall survival. The aim of this prospective study was to assess the usefulness of diffusion-weighted imaging (DWI) in prediction of early therapeutic response of HNSCC after CRT.

Results

Local control was achieved in 22 patients out of 46 patients with pathologically proven HNSCC treated by chemoradiation therapy and local failure was detected in 24 patients out of 46 patients. Pretreatment mean apparent diffusion coefficient (ADCpre) was significantly higher in local failure group (1.1 ± 0.2 × 10−3 mm2/s) than local control group (0.89 ± 0.1 × 10−3 mm2/s). An optimal cut-off value of more than 0.94 × 10−3 mm2/s was predictive of local failure with sensitivity 83.33%, specificity 59.9%, PPV 69%, NPV 76.5%. Early intra-treatment percentage change of ADC (ΔADC) was significantly lower in local failure group (21.8% ± 21.3) than in local control group (45.2% ± 27.8). An optimal cut-off value of ≤ 33% was predictive of local failure after CRT with sensitivity of 71.34%, specificity of 60%, PPV of 62.5%, and NPV of 69.2%.

Conclusions

Diffusion-weighted MRI could be a potential predictive biomarker for therapeutic response of HNSCC to CRT. Primary tumors with higher pretreatment mean ADC, and a smaller early intratreatment percentage increase of mean ADC would be more likely to fail treatment.

Diffusion tensor magnetic resonance imaging of the postoperative spine with metallic implants

There has been a growing need to understand the mechanism of development of acute spinal cord injury (SCI) and to optimize treatment. The paramagnetic nature of metallic implants has hampered the application of diffusion tensor imaging (DTI) in postsurgical SCI monitoring. We describe here a successful implementation of spinal DTI in postsurgical SCI patients. Data were acquired using a single-shot turbo-spin-echo sequence, where an extra gradient is applied before the refocusing pulse train to eliminate contributions from the non-Carr-Purcell-Meiboom-Gill components following a diffusion preparation block where a single-spin echo scheme is deployed. The DTI images were acquired in axial orientation with a 2 x 2 x 4 mm³ resolution and a total of 18 slices. Diffusion gradients were applied in six directions with b values of 0 and 600 seconds/mm² . The whole scan took ~10 minutes. The sequence was compared with SENSE-DW-EPI and ZOOM-DW-EPI on a phantom, eight patients with either anterior or posterior titanium alloy implants, and a pork loin with a similar implant. The protocol resulted in dramatically reduced geometric distortions compared with routine imaging sequences, however, the SNR efficiency was compromised. The spinal cord signal displacement was 0.68±1.00 mm (mean±SD, n = 8) for the proposed protocol, and 5.14±3.07 and 2.82±1.60 mm for the SENSE-DW-EPI and ZOOM-DW-EPI sequences, respectively. Fiber tracking was achieved in the presence of implants, which in one case was accompanied by central spinal cord caviation. Mathematical analysis concluded that the proposed protocol would be generally applicable in the spinal cord when the titanium alloy implant is ~15 mm away (<0.5 kHz B₀ field drift). The protocol described is capable of DTI in postsurgery SCI patients with metallic implants at sufficient resolution and SNR.