Assessment of Masses of the External Ear With Diffusion-Weighted MR Imaging

Multi-parametric arterial spin labeling and diffusion-weighted imaging of paranasal sinuses masses

PURPOSE

To evaluate arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) in discrimination of benign from malignant paranasal sinus (PNS) tumors.

MATERIAL AND METHODS

A prospective study was done upon 42 cases of PNS masses that underwent magnetic resonance ASL and DWI of the head. Tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the masses were calculated by two observers. The pathological diagnosis was malignant (n = 28) and benign (n = 14) cases.

RESULTS

For both observers, the malignant PNS masses had significantly higher TBF (P < 0.001, 0.001) and lower ADC (P < 0.001, 0.001) than in benign masses. The ROC curve analysis of TBF, The threshed TBF was (121.45, 122.68 mL/100 g/min) used for differentiation between benign and malignant PNS masses, revealed sensitivity (92.9%, 89.3%), specificity (85.7%, 85.7%), accuracy (90.5%, 88.1%) and the AUC was 0.87 and 0.86 by both observers. the ROC curve analysis of ADC, The threshold ADC (1.215, 1.205 X10^-3mm2/s) was used for differentiation between benign and malignant PNS masses, revealed sensitivity (96.4%, 89.3%), specificity (78.6%, 78.6%), accuracy of (90.5%, 85.7%) and the AUC was 0.93 and 0.92 by both observers. Combined analysis of TBF and ADC used for differentiation between benign and malignant PNS masses had revealed sensitivity (96.4%, 89.3%), specificity (92.9%, 85.7%) accuracy of (95.2%, 88.1%) and AUC. (0.995, 0.985) for both observers.

CONCLUSION

Combined using of TBF and ADC have a role in differentiation malignant from benign PNS masses.

[Current status of the diagnosis and treatment of temporal bone squamous cell carcinoma]

Temporal bone squamous cell carcinoma, which is rare in the clinical setting, is the most common type of temporal bone malignancy. Its rarity makes the staging, the way of temporal bone resection, the management of parotid gland and cervical lymph node, and the application of radiotherapy and chemotherapy still controversial.There is no unanimous consensus and guideline about it to date at home and abroad.This paper reviewed the recent advance in the diagnosis and treatment of temporal bone squamous cell carcinoma in the hope of providing some help and reference for the management of the disease.

Arterial spin labeling and diffusion-weighted MR imaging: Utility in differentiating idiopathic orbital inflammatory pseudotumor from orbital lymphoma

PURPOSE

To assess arterial spin-labeling (ASL) and diffusion-weighted imaging (DWI) and in combination for differentiating between idiopathic orbital inflammatory pseudotumor (IOIP) and orbital lymphoma.

MATERIAL AND METHODS

A retrospective study was done on 37 untreated patients with orbital masses, suspected to be IOIP or orbital lymphoma that underwent ASL and DWI of the orbit. Quantitative measurement of tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the orbital lesion was done.

RESULTS

There was a significant difference (P = 0.001) in TBF between patients with IOIP (n = 21) (38.1 ± 6.2, 40.3 ± 7.1 ml/100 g/min) and orbital lymphoma (n = 16) (55.5 ± 7.1, 56.8 ± 7.9 ml/100 g/min) for both observers respectively. Thresholds of TBF used for differentiating IOIP from orbital lymphoma were 48, 46 ml/100 g/min revealed area under the curve (AUC) of (0.958 and 0.921), and accuracy of (86% and 83%) for both observers respectively. There was a significant difference (P = 0.001) in ADC between patients with IOIP (1.04 ± 0.19, 1.12 ± 0.23 × 10^-3 mm²/s) and orbital lymphoma (0.69 ± 0.10, 0.72 ± 0.11 × 10^-3 mm²/s) for both observers respectively. Thresholds of ADC used for differentiating IOIP from orbital lymphoma were 0.84 and 0.86 × 10^-3 mm²/s with AUC of (0.933 and 0.920), and accuracy of 89% and 90% for both observers respectively. The combined TBF and ADC used for differentiating IOIP from orbital lymphoma had AUC of (0.973 and 0.970) and accuracy of (91% and 89%) for both observers respectively.

CONCLUSION

TBF and ADC alone and in combination are useful for differentiating IOIP from orbital lymphoma.

Differentiation malignant from benign parotid tumors in children with diffusion-weighted MR imaging

PURPOSE

To differentiate pediatric solid malignant from the benign parotid tumors with diffusion-weighted MR imaging (DWI).

MATERIALS AND METHODS

A retrospective study comprising 38 children with parotid tumors (21 boys and 17 girls aged from 2 months to 17 years) was conducted using (DWI) of the parotid gland. Apparent diffusion coefficient (ADC) maps were generated. The ADC value of the parotid tumors was calculated.

RESULTS

The mean ADC value of malignant parotid tumors (1.08 ± 0.1, 1.04 ± 0.1 × 10^-3mm²/s) was significantly lower [P = 0.001] than that of benign lesions (1.69 ± 0.2, 1.72 ± 0.3 × 10^-3mm²/s). A threshold of ADC of 1.40, 1.33 × 10^-3mm²/s was used for differentiating malignant parotid tumors from benign lesions and led to the best results of the area under the curve of 0.940, 0.929, accuracy of 86, 89%, sensitivity of 94, 94%, specificity of 80, 85%, negative predictive value of 94.1, 94.4%, and positive predictive value of 81, 85%. There was insignificant difference in ADC values of malignant lesions (P = 0.23, 0.30) as well as within benign lesions (P = 0.25, 0.08).

CONCLUSION

DWI is an innovative anticipating imaging technique that can be used in the differentiation of pediatric solid malignant parotid tumors from benign lesions.

Prediction of skull base osteomyelitis in necrotising otitis externa with diffusion-weighted imaging

OBJECTIVE

To predict skull base osteomyelitis in patients with necrotising otitis externa using diffusion-weighted imaging.

METHODS

A retrospective analysis was conducted of 25 necrotising otitis externa patients with skull base osteomyelitis (n = 10) or without skull base involvement (n = 14) who underwent a single-shot diffusion-weighted imaging of the skull base.

RESULTS

The respective mean apparent diffusion coefficient values of the skull base, as determined by two reviewers, were 0.851 ± 0.15 and 0.841 ± 0.14 ×10-3mm2/s for the skull base osteomyelitis patients, and 1.065 ± 0.19 and 1.045 ± 0.20 ×10-3mm2/s for the necrotising otitis externa patients without skull base involvement. The difference in apparent diffusion coefficients between the groups was significant, for both reviewers (p = 0.008 and 0.012). The optimal threshold apparent diffusion coefficient for predicting skull base osteomyelitis in necrotising otitis externa patients was 0.945 ×10-3mm2/s and 0.915 ×10-3mm2/s, with an area under the curve of 0.825 and 0.800, accuracy of 87.5 and 83.3 per cent, sensitivity of 85.7 and 90.0 per cent, and specificity of 90.0 and 78.6 per cent, for each reviewer respectively.

CONCLUSION

Apparent diffusion coefficient is a non-invasive imaging parameter useful for predicting skull base osteomyelitis in necrotising otitis externa patients.

Reliability of diffusion-weighted magnetic resonance imaging in differentiation of recurrent cholesteatoma and granulation tissue after intact canal wall mastoidectomy

Objective

To assess the reliability of diffusion-weighted magnetic resonance imaging in differentiating recurrent cholesteatoma from granulation tissue after intact canal wall mastoidectomy.

Methods

A prospective study was conducted of 56 consecutive patients with suspected cholesteatoma recurrence after intact canal wall mastoidectomy who underwent diffusion-weighted imaging and delayed contrast magnetic resonance imaging of the temporal bone. The final diagnosis was recurrence in 38 patients and granulation tissue in 18 patients.

Results

Cholesteatoma detection on diffusion-weighted imaging based on two sets of readings had sensitivity of 94.7 and 94.7 per cent, specificity of 94.4 and 88.9 per cent, and accuracy of 94.6 and 92.8 per cent, with good intra-observer agreement (Κ= 0.72,p= 0.001). Cholesteatoma detection on delayed contrast magnetic resonance imaging had sensitivity of 81.6 and 78.9 per cent, specificity of 77.8 and 66.7 per cent, and accuracy of 80.4 and 75.0 per cent, with fair intra-observer agreement (Κ= 0.57,p= 0.001). The mean cholesteatoma diameter on diffusion-weighted imaging was 7.7 ± 1.8 and 7.9 ± 1.8 mm, with excellent intra-observer agreement (Κ= 0.994,p= 0.001).

Conclusion

Diffusion-weighted imaging is a reliable method for differentiating recurrent cholesteatoma and granulation tissue after intact canal wall mastoidectomy.

Differentiation of sublingual thyroglossal duct cyst from midline dermoid cyst with diffusion weighted imaging

PURPOSE

to differentiate sublingual thyroglossal duct cyst (TGDC) from midline dermoid cyst (DC) with diffusion weighted imaging (DWI).

MATERIALS AND METHODS

Retrospective analysis of 22 consecutive patients (11 male and 11 female aged 5-15 years) with midline cystic lesion at floor of mouth. They underwent DWI of floor of mouth. Apparent diffusion coefficient (ADC) of the cystic lesions was calculated and correlated with surgical findings.

RESULTS

The mean ADC value of TGDC of 1st observer was (2.20 ± 0.28 × 10^-3 mm²/s) and of 2nd observer was (2.28 ± 0.27 × 10^-3 mm²/s) was significantly higher than that of DC (P = 0.001) whose ADC of 1st observer was (1.55 ± 0.15 × 10^-3 mm²/s) and of 2nd observer was (1.53 ± 0.11 × 10^-3 mm²/s). There was excellent inter-observer agreement of both readings (r = 92%, P = 0.001). When ADC of 1.76 and 1.62 × 10^-3 mm²/s was used as a threshold value for differentiating TGDC from DC, the best results were obtained with area under the curve of 0.94 and 0.96, accuracy of 90% and 86%, sensitivity of 91% and 91%%, specificity of 90% and 80%, negative predictive value of 90% and 88% and positive predictive value of 92% and 84% of both reviewers respectively.

CONCLUSION

DWI is reliable and reproducible imaging modality for differentiation sublingual TGDC from DC.

Influence of blade width and magnetic field strength on the ADC on PROPELLER DWI in head and neck

PURPOSE

The purpose of this study was to investigate the influence of blade width and magnetic field strength on apparent diffusion coefficient values of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion-weighted imaging in the head and neck at 1.5 and 3.0 T magnetic resonance imaging.

METHODS

Fifteen healthy volunteers (eight men and seven women; mean age 36.4 ± 10.1 years) underwent PROPELLER diffusion-weighted imaging using four blade widths at 3.0 T and three blade widths at 1.5 T. For the multigroup comparison of apparent diffusion coefficient values, we performed analysis of variance and Tukey-Kramer tests. The apparent diffusion coefficient values in each organ were compared among the different blade widths and magnetic field strengths by a t test. Inter and intra-observer agreements regarding apparent diffusion coefficient value measurements were evaluated using the intraclass correlation coefficient.

RESULTS

No significant differences were observed in apparent diffusion coefficient values of the cerebellum in each blade width at both field strengths. The apparent diffusion coefficient values of the right parotid glands were significantly lower for blade width 32 than for blade width 16 at 3.0 T (1.16 × 10^-3 mm²/s vs. 1.01 × 10^-3 mm²/s; P < 0.05). The apparent diffusion coefficient values of bilateral parotid glands were significantly higher at 1.5 T than at 3.0 T. Intraclass correlation coefficients were almost perfect to substantial in the cerebellum, whereas they showed moderate agreement in the parotid glands.

CONCLUSION

The largest blade width 32 at 3.0 T and high magnetic field strength lowered the apparent diffusion coefficient values of parotid glands of PROPELLER diffusion-weighted imaging. The apparent diffusion coefficient values in the parotid glands of PROPELLER diffusion-weighted imaging may be affected for blade width and magnetic field strength.

The routes of infection spread in central skull-base osteomyelitis and the diagnostic role of CT and MRI scans

Background

Central skull-base osteomyelitis (CSBO) represents a life-threatening complication of external ear canal infection. Computed tomography (CT) and magnetic resonance imaging (MRI) play key roles in assessment of CSBO progression.

Methods

Twelve patients with CSBO were included in a retrospective clinical study. In total, 62 scans (30 CTs and 32 MRIs) were performed to evaluate the extent of inflammatory changes. The scans were read independently by two radiologists specialised in imaging of the head and neck. The regions under the skull base were specified using the online Anatomy Atlas of the skull base. To clarify the timeline, the time period was divided into four parts, and inflammatory changes in the skull-base regions were tracked. Data were statistically analysed.

Results

In early stages of the disease, CT scan detects inflammatory changes closely related to the stylomastoid foramen and medially to the posterior belly of the digastric muscle, changes which have been proved to be crucial for the diagnosis of CSBO. Later the infection spreads to the contralateral side causing demineralisation of the bones.

Conclusion

Imaging methods play a crucial role not only in establishing the diagnosis, but also in anticipating the direction of infection spread underneath the skull base.

Arterial spin labelling and diffusion-weighted magnetic resonance imaging in differentiation of recurrent head and neck cancer from post-radiation changes

Objective

To assess arterial spin labelling and diffusion-weighted imaging in the differentiation of recurrent head and neck cancer from post-radiation changes.

Methods

A retrospective study was conducted of 47 patients with head and neck cancer, treated with radiotherapy, who underwent magnetic resonance arterial spin labelling and diffusion-weighted magnetic resonance imaging. Tumour blood flow and apparent diffusion co-efficient of the lesion were calculated.

Results

There was significant difference (p= 0.001) in tumour blood flow between patients with recurrent head and neck cancer (n= 31) (47.37 ± 16.3 ml/100 g/minute) and those with post-radiation changes (n= 16) (18.80 ± 2.9 ml/100 g/minute). The thresholds of tumour blood flow and apparent diffusion co-efficient used for differentiating recurrence from post-radiation changes were more than 24.0 ml/100 g/minute and 1.21 × 10−3mm2/second or less, with area under the curve values of 0.94 and 0.90, and accuracy rates of 88.2 per cent and 88.2 per cent, respectively. The combined tumour blood flow and apparent diffusion co-efficient values used for differentiating recurrence from post-radiation changes had an area under the curve of 0.96 and an accuracy of 90.2 per cent.

Conclusion

Combined tumour blood flow and apparent diffusion co-efficient can differentiate recurrence from post-radiation changes.

New methods for specialized subjective and high-precision objective evaluation of constricted ears: A pilot study

The effects of therapy on constricted ears are evaluated subjectively and objectively. However, previous methods are not specific, comprehensive, precise, or effective in diagnosing and predicting surgical outcomes. This study aimed to present a personalized, subjective evaluation scale and new objective indices utilizing a digital method for the accurate evaluation of constricted ears.Nine consecutive patients with constricted ears were selected. To perform subjective evaluations, the patients' parents were contacted by telephone within 3 to 6 months after surgery and asked to answer questions using a scale. To perform objective evaluations, the constricted and normal ears of each patient were scanned using a 3-dimensional scanner before and 14 days after surgery. The vertical height of the auricle (VHA), transverse diameter of the auricle, minimum length of the helix (MLH), length of the inner auricle (LIA), and transverse diameter of the inner auricle were calculated using Mimics software. The Wilcoxon matched pairs signed-rank test was used for data analysis.High satisfaction scores were reported. The folds of the ear and helix had the highest median scores, whereas the crus of the antihelix had the lowest. The difference in LIA and postoperative MLH was greater than that in VHA and preoperative MLH. The mean values of the 5 indices of the normal ear were greater than those of the indices of the preoperative constricted ear (P < .05).The specialized subjective scale reported in this study allows comprehensive and personalized assessment of constricted ears. The new objective indices are more effective than existing methods and the digital measurement method is precise and reliable. These methods will allow the treatment of constricted ears to be better evaluated, leading to improvements in patient management and treatment selection.

Prediction of venous malformations with localized intravascular coagulopathy with diffusion-weighted magnetic resonance imaging

Background

Venous malformations may be complicated by localized intravascular coagulopathy which is a serious condition with hematological sequel. Prediction of localized intravascular coagulopathy is mandatory for prompt anticoagulation therapy. Laboratory and routine magnetic resonance imaging can predict localized intravascular coagulopathy in venous malformations; however, the results are variable.

Purpose

To predict venous malformations with localized intravascular coagulopathy with diffusion-weighted magnetic resonance imaging.

Material and methods

A retrospective analysis was performed on 55 patients (34 male, 21 female aged 14–64 years: mean 39 years) with venous malformations that underwent diffusion-weighted magnetic resonance imaging. The apparent diffusion coefficient value of venous malformations was calculated.

Results

The mean apparent diffusion coefficient value of venous malformations with localized intravascular coagulopathy (n = 26) (1.28 ± 0.18 × 10−3 mm2/s) was significantly different ( P = 0.001) from venous malformations without localized intravascular coagulopathy (n = 29) (1.60 ± 0.18 × 10−3 mm2/s). When apparent diffusion coefficient value of 1.454 × 10−3 mm2/s was used as a threshold value for the prediction of venous malformations with localized intravascular coagulopathy, the best result was obtained with an accuracy of 83.6%, sensitivity of 84.6%, specificity of 82.8%, and area under the curve of 0.895. The apparent diffusion coefficient value of venous malformations was correlated with D-dimer level ( r = −0.59, P = 0.006) and fibrinogen level ( r = 0.73, P = 0.001).

Conclusion

The apparent diffusion coefficient value is a non-invasive imaging parameter that can be used to predict venous malformations with localized intravascular coagulopathy.