Complementary roles of MRI and endoscopic examination in the early detection of nasopharyngeal carcinoma.

BACKGROUND: Early-stage nasopharyngeal carcinoma (NPC) evades detection when the primary tumor is hidden from view on endoscopic examination. Therefore, in a prospective study of subjects being screened for NPC using plasma Epstein-Barr virus (EBV) DNA, we conducted a study to investigate whether magnetic resonance imaging (MRI) could detect endoscopically occult NPC. PATIENTS AND METHODS: Participants with persistently positive EBV DNA underwent endoscopic examination and biopsy when suspicious for NPC, followed by MRI blinded to the endoscopic findings. Participants with a negative endoscopic examination and positive MRI were recalled for biopsy or surveillance. Diagnostic performance was assessed by calculating sensitivity, specificity and accuracy, based on the histologic confirmation of NPC in the initial study or in a follow-up period of at least two years. RESULTS: Endoscopic examination and MRI were performed on 275 participants, 34 had NPC, 2 had other cancers and 239 without cancer were followed-up for a median of 36 months (24-60 months). Sensitivity, specificity and accuracy were 76.5%, 97.5% and 94.9%, respectively, for endoscopic examination and 91.2%, 97.5% and 96.7%, respectively, for MRI. NPC was detected only by endoscopic examination in 1/34 (2.9%) participants (a participant with stage I disease), and only by MRI in 6/34 (17.6%) participants (stage I = 4, II = 1, III = 1), two of whom had stage I disease and follow-up showing slow growth on MRI but no change on endoscopic examination for 36 months. CONCLUSION: MRI has a complementary role to play in NPC detection and can enable the earlier detection of endoscopically occult NPC.

Head and neck ultrasound: technical advances, novel applications and the role of elastography.

High-resolution ultrasound (US) provides superb anatomical detail in the superficial anatomy of the neck and has become the first-line imaging investigation for neck lumps and a crucial component of clinical pathways. In this article, a wide range of advances in neck US are described with a focus on the emerging role of ultrasound elastography. Selected examples of clinical utility are presented across a spectrum of scenarios with discussion of newer applications, service delivery, and training issues. The changing role of the neck ultrasound practitioner and the future of the technique in the head and neck are considered.

Staging nodal metastases in nasopharyngeal carcinoma: which method should be used to measure nodal dimension on MRI?

AIM: To investigate four methods to measure the maximum dimension (MD) of metastatic neck nodes and correlate with clinical outcome in nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Magnetic resonance imaging (MRI) examinations of 712 NPC patients were analysed. MD measurements using methods 1, 2, 3, and 4 were obtained from a single node in the axial plane; a single node in the axial/coronal plane; a single and/or confluent nodes in the axial/coronal plane; and a single and/or confluent and/or contiguous nodes in the axial/coronal plane, respectively. MDs obtained from the four methods were correlated with nodal volume (NV) using Pearson's correlation test. MDs obtained from the four methods, T and N stages, age, gender, and treatment were correlated with overall survival (OS), disease-specific survival (DSS), distant metastases free survival (DMFS), and regional relapse-free survival (RRFS) using cox regression. RESULTS: Method 4 (R: 0.84) had the strongest correlation with NV followed by method 3 (R: 0.77), method 2 (R: 0.70) and method 1(R: 0.69). Method 4 was the only independent nodal measurement of OS, DSS, and DMFS (p-values = 0.008, <0.001 and <0.001, respectively). None of the MD methods was an independent measurement of RRFS. CONCLUSIONS: The best method to obtain the MD for staging incorporates not only single and confluent, but also contiguous metastatic nodes measured in the plane with the MD.

The influence of precompression on elasticity of thyroid nodules estimated by ultrasound shear wave elastography.

OBJECTIVES: To investigate the influence of variations in resting pressure (precompression) on thyroid ultrasound supersonic shear wave elastography (SWE). METHODS: Thirty-five normal thyroid glands (Norm), 55 benign hyperplastic nodules (BHN), and 17 papillary thyroid cancers (PTC) in 96 subjects underwent thyroid SWE. Four precompression levels were applied manually by the operator, ranging from A (baseline, 0 % strain) to D (high, 22-30 % strain). SWE results at each precompression level were compared using ANOVA tests with P < 0.05 indicating significance. RESULTS: SWE indices were highest in PTC, followed by BHN and Norm at each precompression level (P < 0.05). All tissue types showed successive increases in SWE results as precompression increased, although the rate was higher for PTC than BHN and Norm (Ps < 0.05). SWE values (kPa) of Norm, BHN, and PTC at baseline precompression (A) were 10.3 ± 3.3, 17.7 ± 7.6, and 22.2 ± 11.9 compared with 21.1 ± 4.2, 42.3 ± 16.0, and 97.6 ± 46.8 at high precompression (D). SWE index differences between precompression levels A and D were 10.8 kPa for Norm, 24.6 kPa for BHN, and 75.4 kPa for PTC. CONCLUSION: PTCs show greater SWE stiffening than BHN as precompression rises. Precompression effects on thyroid nodules are not negligible and may account for wide discrepancies in published SWE discriminatory performance results for thyroid malignancy. KEY POINTS: • Increases in resting pressure (precompression) applied by the operator increases thyroid stiffness. • Papillary cancers show greater increases in stiffness (strain hardening) than benign nodules. • Precompression may affect the diagnostic performance of shearwave elastography for thyroid malignancy.

Unusual parotid gland lesions: a pictorial review.

This is a pictorial essay of unusual parotid gland lesions that may be encountered in routine clinical practice.

Under-mask beard covers achieve an adequate seal with tight-fitting disposable respirators using quantitative fit testing.

BACKGROUND: Tight-fitting respirators are a critical component of respiratory protection against airborne diseases for health workers. However, they are not recommended for health workers with facial hair. Some health workers are unable to shave for religious or medical reasons. Under-mask beard covers have been proposed as a solution to allow health workers with facial hair to wear tight-fitting respirators. However, studies to date have been limited by their predominant reliance on qualitative rather than quantitative fit testing techniques. AIM: To assess the efficacy of under-mask beard covers in achieving an adequate seal with tight-fitting disposable P2/N95 respirators using quantitative fit testing. METHODS: Bearded adult males underwent quantitative fit testing with an under-mask beard cover using either a TSI PortaCount Respirator Fit Tester 8038 or an AccuFit 9000 PRO fit testing device on up to five disposable P2/N95 respirators (3M 1860, 3M 1870+, BYD N95 Healthcare Particulate Respirator, BSN Medical ProShield N-95 Medium and Trident RTCFFP2). The primary outcome was the proportion of subjects that passed or failed quantitative fit testing with an under-mask beard cover. FINDINGS: Thirty subjects were assessed; of these, 24 (80%) passed quantitative fit testing with at least one tight-fitting P2/N95 disposable respirator. Among these subjects, the median best-achieved fit factor was 200 (interquartile range 178-200). None of the subjects had an adverse reaction to the under-mask beard cover. CONCLUSION: The under-mask beard cover technique may be used to achieve a satisfactory seal with tight-fitting P2/N95 respirators in health workers with facial hair who cannot shave.

Cystic change in thyroid nodules: a confounding factor for real-time qualitative thyroid ultrasound elastography.

OBJECTIVE: To evaluate real-time qualitative ultrasound elastography for focal thyroid masses undergoing fine-needle aspiration in a routine thyroid ultrasound clinic. MATERIALS AND METHODS: Ninety-four thyroid nodules scheduled for fine-needle aspiration cytology in a thyroid ultrasound clinic also underwent real-time freehand elastography. Colour-scaled elastograms were graded visually on the stiffness of the solid component of nodules relative to thyroid parenchyma using an elastography score (ES) scale from 1 (soft) to 4 (stiff). The ES for benign and malignant nodules and the influence of cystic change on ES were analysed using Chi-square with trend and Fishers exact tests, with a p<0.05 used to indicate statistical significance. RESULTS: There were 19 papillary carcinomas, five metastases, 57 hyperplastic nodules, and four follicular adenomas based on definitive cytology (n=54) or histology (n=31). Nine nodules were excluded due to indeterminate cytology and no histology. Of malignancies (all solid), two were ES=1, four were ES=2, eight were ES=3, and 10 were ES=4. Of benign nodules, 17 were ES=1, 17 were ES=2, 16 were ES=3, and 11 were ES=4. An ES>2 was more common in benign nodules with predominant cystic components (17/18) than mildly cystic (3/12) or completely solid (7/31) benign nodules (p=0.0004, p<0.0001). The ES was not significantly different between benign and malignant nodules (p=0.09) unless partially cystic nodules were excluded (p=0.005). For solid nodules, an ES>2 optimally predicted malignancy, achieving 74% sensitivity, 77% specificity, and 76% accuracy. CONCLUSION: Qualitative real-time thyroid elastography predicts malignancy only if predominantly cystic nodules are excluded, which may limit its utility in routine clinical practice.

MR Imaging Criteria for the Detection of Nasopharyngeal Carcinoma: Discrimination of Early-Stage Primary Tumors from Benign Hyperplasia.

BACKGROUND AND PURPOSE: MR imaging can detect nasopharyngeal carcinoma that is hidden from endoscopic view, but for accurate detection carcinoma confined within the nasopharynx (stage T1) must be distinguished from benign hyperplasia of the nasopharynx. This study aimed to document the MR imaging features of stage T1 nasopharyngeal carcinoma and to attempt to identify features distinguishing it from benign hyperplasia. MATERIALS AND METHODS: MR images of 189 patients with nasopharyngeal carcinoma confined to the nasopharynx and those of 144 patients with benign hyperplasia were reviewed and compared in this retrospective study. The center, volume, size asymmetry (maximum percentage difference in area between the right and left nasopharyngeal halves), signal intensity asymmetry, deep mucosal white line (greater contrast enhancement along the deep tumor margin), and absence/distortion of the adenoidal septa were evaluated. Differences were assessed with logistic regression and the χ2 test. RESULTS: The nasopharyngeal carcinoma center was lateral, central, or diffuse in 134/189 (70.9%), 25/189 (13.2%), and 30/189 (15.9%) cases, respectively. Nasopharyngeal carcinomas involving the walls showed that a deep mucosal white line was present in 180/183 (98.4%), with a focal loss of this line in 153/180 (85%) cases. Adenoidal septa were absent or distorted in 111/111 (100%) nasopharyngeal carcinomas involving the adenoid. Compared with benign hyperplasia, nasopharyngeal carcinoma had a significantly greater volume, size asymmetry, signal asymmetry, focal loss of the deep mucosal white line, and absence/distortion of the adenoidal septa (P < .001). Although size asymmetry was the most accurate criterion (89.5%) for nasopharyngeal carcinoma detection, use of this parameter alone would have missed 11.9% of early-stage T1 nasopharyngeal carcinomas. CONCLUSIONS: MR imaging features can help distinguish stage T1 nasopharyngeal carcinoma from benign hyperplasia in most cases.

Diffusion-Weighted Imaging of Nasopharyngeal Carcinoma: Can Pretreatment DWI Predict Local Failure Based on Long-Term Outcome?

BACKGROUND AND PURPOSE: Pretreatment prediction of patients with nasopharyngeal carcinoma who will fail conventional treatment would potentially allow these patients to undergo more intensive treatment or closer posttreatment monitoring. The aim of the study was to determine the ability of pretreatment DWI to predict local failure in patients with nasopharyngeal carcinoma based on long-term clinical outcome. MATERIALS AND METHODS: One hundred fifty-eight patients with pretreatment DWI underwent analysis of the primary tumor to obtain the ADC mean, ADC skewness, ADC kurtosis, volume, and T-stage. Univariate and multivariate analyses using logistic regression were performed to compare the ADC parameters, volume, T-stage, and patient age in primary tumors with local failure and those with local control, by using a minimum of 5-year follow-up to confirm local control. RESULTS: Local control was achieved in 131/158 (83%) patients (range, 60.3-117.7 months) and local failure occurred in 27/158 (17%) patients (range, 5.2-79.8 months). Compared with tumors with local control, those with local failure showed a significantly lower ADC skewness (ADC values with the greatest frequencies were shifted away from the lower ADC range) (P = .006) and lower ADC kurtosis (curve peak broader) (P = .024). The ADC skewness remained significant on multivariate analysis (P = .044). There was a trend toward higher tumor volumes in local failure, but the volume, together with T-stage and ADC mean, were not significantly different between the 2 groups. CONCLUSIONS: Pretreatment DWI of primary tumors found that the skewness of the ADC distribution curve was a predictor of local failure in patients with nasopharyngeal carcinoma, based on long-term clinical outcome.

Detection of Nasopharyngeal Carcinoma by MR Imaging: Diagnostic Accuracy of MRI Compared with Endoscopy and Endoscopic Biopsy Based on Long-Term Follow-Up.

BACKGROUND AND PURPOSE: Our previous nasopharyngeal carcinoma detection study, comparing MR imaging, endoscopy, and endoscopic biopsy, showed that MR imaging is a highly sensitive test that identifies nasopharyngeal carcinomas missed by endoscopy. However, at the close of that study, patients without biopsy-proved nasopharyngeal carcinoma nevertheless had shown suspicious abnormalities on endoscopy and/or MR imaging. The aim of this study was to determine whether there were any patients with undiagnosed nasopharyngeal carcinoma by obtaining long-term follow-up and to use these data to re-evaluate the diagnostic performance of MR imaging. MATERIALS AND METHODS: In the previous study, 246 patients referred to a hospital ear, nose, and throat clinic with suspected nasopharyngeal carcinoma, based on a wide range of clinical indications, had undergone MR imaging, endoscopy, and endoscopic biopsy, and 77 had biopsy-proved nasopharyngeal carcinoma. One hundred twenty-six of 169 patients without biopsy-proved nasopharyngeal carcinoma underwent re-examination of the nasopharynx after a minimum of 3 years, including 17 patients in whom a previous examination (MR imaging = 11; endoscopy = 7) had been positive for nasopharyngeal carcinoma, but the biopsy had been negative for it. Patients with nasopharyngeal carcinoma were identified by biopsy obtained in the previous and this follow-up study; patients without nasopharyngeal carcinoma were identified by the absence of a tumor on re-examination of the nasopharynx. The sensitivity and specificity of the previous investigations were updated and compared by using the Fisher exact test. RESULTS: One patient with a previous positive MR imaging finding was subsequently proved to have nasopharyngeal carcinoma. Nasopharyngeal carcinomas were not found in the remaining 125 patients at follow-up, and the previous positive findings for nasopharyngeal carcinoma on MR imaging and endoscopy were attributed to benign lymphoid hyperplasia. The diagnostic performances for the previous MR imaging, endoscopy, and endoscopic biopsy were 100%, 88%, and 94%, respectively, for sensitivity, and 92%, 94%, and 100%, respectively, for specificity; the differences between MR imaging and endoscopy were significant for sensitivity (P = .003) but not specificity (P = .617). CONCLUSIONS: MR imaging detected the 12% of nasopharyngeal carcinomas that were endoscopically invisible, including 1 cancer that remained endoscopically occult for several years. Lymphoid hyperplasia reduced the specificity of MR imaging.

Synergistic effect of iontophoresis and a series of fatty acids on LHRH permeability through porcine skin.

The effect of chemical penetration enhancers (e.g., fatty acids) in combination with iontophoresis was examined on the in vitro permeability of luteinizing hormone releasing hormone (LHRH) through porcine skin. Porcine epidermis was pretreated with either ethanol (EtOH) or 10% fatty acid/EtOH. The permeability coefficient of LHRH was significantly (p < 0.05) greater through EtOH, lauric acid/EtOH, palmitic acid/EtOH, oleic acid/EtOH, linoleic acid/EtOH, and linolenic acid/EtOH treated epidermis than the control (untreated epidermis). Iontophoresis further enhanced the permeability of LHRH (p < 0.05) through enhancer-pretreated epidermis in comparison with corresponding passive permeability. Among saturated fatty acids tested, 10% palmitic acid/iontophoresis showed the highest permeability coefficient [(59.52 +/- 2.40) x 10(-4) cm/h], which was approximately 16-fold higher than that of the control [(3.57 +/- 0.41) x 10(-4) cm/h]. Unsaturated cis-octadecenoic acids were more effective penetration enhancers when compared with octadecanoic acid. Among cis-octadecenoic acids in combination with EtOH, the greater iontophoretic permeability coefficient [(59.18 +/- 12.43) x 10(-4) cm/h] was obtained through linolenic acid treated epidermis, which was significantly greater (p < 0.05) than through saturated octadecanoic acid treated epidermis [(29.08 +/- 3.18) x 10(-4) cm/h]. Also, pretreatment of epidermis with 5% linolenic acid/propylene glycol (PG) resulted in greater (p < 0.05) iontophoretic flux of LHRH in comparison to 5% linolenic acid/EtOH. Furthermore, increases in the degree of unsaturation in octadecenoic acids did not produce corresponding increases in the degree of enhancement. Reversibility studies revealed that the postrecovery passive flux of LHRH through 5% linolenic acid in combination with EtOH or PG/iontophoresis treated epidermis was significantly (p < 0.05) reduced than the prerecovery value but could not completely recover to the baseline flux (i.e., flux of LHRH through untreated epidermis).

Effect of penetration enhancers and iontophoresis on the ultrastructure and cholecystokinin-8 permeability through porcine skin.

The present study explores the effect of chemical penetration enhancers and iontophoresis on the in vitro permeability of cholecystokinin-8 (CCK-8) through porcine epidermis and on the ultrastructural changes in stratum corneum as observed by transmission electron microscopy (TEM). Enhancer [i.e., ethanol (EtOH), and 10% oleic acid in combination with ethanol (OA/EtOH)] pretreatment significantly increased (p < 0.01) the permeability coefficient of CCK-8 in comparison with the control (pretreated epidermis without enhancer). Iontophoresis further increased the permeability of CCK-8 (p < 0.01) through the enhancer-pretreated epidermis in comparison with the control. These results showed the synergistic effect of iontophoresis and enhancers such as OA/EtOH that provides an additional driving force to maintain and control the target flux of CCK-8. The ultrastructure of stratum corneum treated with ethanol demonstrated a loss of structural components in the superficial stratum corneum cell layers. OA/EtOH transformed the highly compact cells of stratum corneum into a looser network of filaments, creating an increased free volume and greater intracellular surface area. Treatment of stratum corneum with OA/EtOH followed by iontophoresis resulted in further swelling of stratum corneum cell layers. In conclusion, OA/EtOH in combination with iontophoresis increased the permeability of CCK-8 by loosening and swelling of stratum corneum cell layers.

Effect of linolenic acid/ethanol or limonene/ethanol and iontophoresis on the in vitro percutaneous absorption of LHRH and ultrastructure of human epidermis.

The effect of enhancer(s) (e.g. ethanol (EtOH), 5% linolenic acid/EtOH, and 5% limonene/EtOH) and iontophoresis was investigated on the in vitro percutaneous absorption of luteinizing hormone releasing hormone (LHRH) and ultrastructure of human epidermis by transmission electron microscopy (TEM). 5% linolenic acid/EtOH or 5% limonene/EtOH significantly enhanced (P<0.05) the passive flux of LHRH through human epidermis in comparison to the control (no enhancer treated epidermis). Iontophoresis further increased the flux of LHRH through enhancer(s) treated epidermis. Iontophoretic flux of LHRH through 5% linolenic acid/EtOH and 5% limonene/EtOH treated epidermis was significantly (P<0.05) enhanced in comparison to iontophoretic flux through the control epidermis. TEM is the most efficient way to visualize the ultrastructure of the stratum corneum (SC). TEM results reveal that iontophoresis in combination with enhancers (e.g. linolenic acid/EtOH or and limonene/EtOH) transformed the highly compact cells of the SC into a looser network of filaments, disrupted the keratin pattern, and resulted in swelling of SC cell layers of human epidermis. Thus, linolenic acid/EtOH or limonene/EtOH in combination with iontophoresis increased the flux of LHRH through human epidermis by disrupting keratin pattern as well as loosening and swelling of SC cell layers.

Measurement of fluorescence decay of crude oil: a potential technique to identify oil slicks.

The single photon counting technique has been used to measure the decay time for several Kuwaiti crude and refined oils. Fluorescent characteristics of two different bunker oils from widely separate geographic areas have been studied. Laser induced fluorescent data for the crude oil samples are compared with the decay time results to evaluate the potential of these techniques for the identification of oil sticks in the marine environment. Response of the oil film thickness to various excitation wavelengths from a CW Ar ion laser and a pulsed xenon lamp has been investigated.

Laser ablation of gall bladder stones.

Study of laser interaction with calculi is presented. A system of Nd-Yag and Ho-Yag pulsed lasers were used to produce fluorescence and plasma signals at the stone surface surrounded by saline and bile fluids. Fourth harmonic from Nd-Yag laser was transmitted to the samples by graded UV optical fibres. Gall bladder stones of various compositions were subjected to the high power Ho-Yag laser. Temporal transients and spectral evolution of plasma and fluorescence signals were monitored by a streak camera. A profile of acoustic pressures generated by shock waves was recorded with sensitive hydrophones placed in the surrounding fluids. Ablation threshold, cavitation process and fluorescence dependence on the laser parameters were studied in detail. Potential of stone identification by fluorescence and possible hydrodynamic model for ablation of biological samples is discussed.

Review of ultrasonography of malignant neck nodes: greyscale, Doppler, contrast enhancement and elastography.

Assessment of neck lymph nodes is essential in patients with head and neck cancers for predicting the patient's prognosis and selecting the appropriate treatment. Ultrasonography is a useful imaging tool in the assessment of neck lymph nodes. Greyscale ultrasonography assesses the size, distribution, and internal architecture of lymph nodes. Doppler ultrasonography evaluates the intranodal vascular pattern and resistance of lymph nodes. Contrast-enhanced ultrasonography provides information on lymph node parenchymal perfusion. Elastography allows qualitative and quantitative assessment of lymph node stiffness. This article reviews the value of greyscale, Doppler and contrast-enhanced ultrasonography as well as elastography in the assessment of malignant nodes in the neck.

The Bonebridge semi-implantable bone conduction hearing device: experience in an Asian patient.

For over three decades, bone conduction hearing aids have been changing the lives of patients with impaired hearing. The size, appearance and fitting discomfort of early generations of bone conduction hearing aids made them unpopular. The advent of bone-anchored hearing aids in the 1970s offered patients improved sound quality and fitting comfort, due to the application of osseointegration. However, the issue of post-operative peri-abutment pin tract wound infection persisted. The Bonebridge system incorporates the first active bone conduction device, and aims to resolve peri-abutment issues. Implantation of this system in an Asian patient is presented.

T2-weighted MR imaging early after chemoradiotherapy to evaluate treatment response in head and neck squamous cell carcinoma.

BACKGROUND AND PURPOSE: T2-weighted MRI shows potential in early posttreatment assessment of the primary tumor. Residual masses composed entirely of low T2-signal scar tissue suggest local control and those ≥1 cm of similar signal to untreated tumor suggest local failure. The purpose of this study was to investigate the diagnostic accuracy of T2-weighted MR imaging early after chemoradiotherapy for identifying primary tumor treatment failure in squamous cell carcinoma of the head and neck. MATERIALS AND METHODS: At 6 weeks after treatment, T2-weighted MR images of 37 primary tumors in 37 patients were assessed. Residual masses were divided into 3 patterns: pattern 1 = scar tissue only (flat-edged/retracted mass of low T2 signal intensity); pattern 2 = mass without features described in pattern 1 or 3; and pattern 3 = any pattern that included an expansile mass ≥1 cm of intermediate T2 signal intensity (similar grade of signal intensity to the untreated tumor). T2 patterns were analyzed for local outcome (Fisher exact test) and time to local failure (univariate and multivariate analysis of T2 pattern, age, T stage, and tumor size by use of the Cox regression model). RESULTS: Residual masses after treatment were present in 34 (92%) of 37 patients. Local failures occurred in residual masses with pattern 1 in 0 (0%) of 14 patients; pattern 2 in 6 (55%) of 11 patients; and pattern 3 in 9 (100%) of 9 patients. Significant associations were found between local control and pattern 1 (P = <.0001; sensitivity, 74%; specificity, 100%; PPV, 100%; NPV, 75%; accuracy, 85%), and between local failure and pattern 3 (P = <.0001; sensitivity, 60%; specificity, 100%; PPV, 100%; NPV, 76%; accuracy, 82%). Pattern 2 showed no significant associations with local outcome. Univariate analysis of time to local failure showed that the T2 pattern was significant (P < .0001) and remained significant on multivariate analysis. CONCLUSIONS: T2-weighted MR imaging is a potential tool for early posttreatment assessment of primary HNSCC treatment response. Awareness of correlation of the T2 pattern of any residual mass with treatment outcome at the primary site may contribute to patient treatment.

Can diffusion-weighted imaging distinguish between normal and squamous cell carcinoma of the palatine tonsil?

The utility of diffusion-weighted imaging (DWI) in the detection of squamous cell carcinoma (SCC) of the tonsils has not been previously investigated. This preliminary study compared DWI of apparent SCC tonsillar tumours with normal tonsils. DWI of the tonsils was performed in 10 patients with newly diagnosed tonsil SCC that was evident on conventional MRI and in 17 patients undergoing cranial MRI for other indications. Regions of interest (ROI) were drawn around each identifiable tonsil on the apparent diffusion coefficient (ADC) map and the mean ADC value for each tonsil was calculated. ADC values for normal and SCC tonsils were compared using the Mann-Whitney U-test. The median ADC and range (x10(-3) mm(2) s(-1)) were found to be 0.814 and 0.548-1.312, respectively, for normal tonsils compared with 0.933 and 0.789-1.175, respectively, for SCC tonsils. ADC values were significantly higher for SCC tonsils than for normal tonsils (p = 0.009). No SCC tonsil had an ADC less than 0.82 x 10(-3) mm(2) s(-1) compared with 58% of normal tonsils. We conclude that there is a difference in the ADC between normal tonsils and SCC tonsils where the cancer is apparent on conventional MRI. These results are promising, although further studies are now required to determine whether DWI can be used to identify or exclude smaller foci of SCC within tonsils where the cancer is not evident on conventional MRI.

Does primary tumour volumetry performed early in the course of definitive concomitant chemoradiotherapy for head and neck squamous cell carcinoma improve prediction of primary site outcome?

Although previous studies have documented correlations between pre-treatment or post-treatment primary tumour volumes and local outcome following definitive concomitant chemoradiotherapy (CCRT) in head and neck squamous cell carcinoma (HNSCC), no study has included and compared tumour volumes during CCRT. We reviewed the MRIs of 69 HNSCC patients treated with a 6 weeks course of CCRT and who underwent successful MRI pre-treatment (n = 69), 2 weeks intra-treatment (n = 48) and 6 weeks post-treatment (n = 61). Primary tumour volumes on MRI at the three time points were calculated and compared for their predictive value for primary site outcome. Volume thresholds optimised to predict failure with the highest accuracy and positive predictive value (PPV) were calculated. The mean pre-treatment volume was 24.6 cm³ (range, 1.1-187.9 cm³) and the mean follow-up interval was 41 months (range, 12-100 months). 23 primary tumours failed treatment (33%). Volumes before, during and after CCRT were positively associated with local failure (p = 0.015, p = 0.009, p<0.0001). Volume reductions during and after CCRT were negatively associated with local failure (p = 0.021, p = 0.001). Pre-treatment and intra-treatment volume thresholds achieved the highest accuracy and produced intermediate PPVs (51-64%) for predicting local failure. Optimised intra-treatment thresholds did not identify any more treatment failures than the pre-treatment thresholds. By comparison, a 6 weeks post-treatment volume reduction (<35%) achieved 100% PPV for failure, albeit with 26% sensitivity. In conclusion, primary tumour volumetry performed early in CCRT provides minimal additional information compared with pre-treatment volumetry, with respect to predicting post-treatment local failures. Therefore, volumetry during CCRT is unlikely to be useful for guiding individual response-based therapeutic modifications.