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.

A Comparison of the Diagnostic Accuracy and Reliability of Subjective Grading and Computer-Aided Assessment of Intranodal Vascularity in Differentiating Metastatic and Reactive Cervical Lymphadenopathy.

PURPOSE: Ultrasound is a well-established imaging modality in the assessment of malignant cervical lymphadenopathy. With the use of Doppler ultrasound, intranodal vascularity can be evaluated. However, the major limitation of ultrasound is operator dependency. Therefore, this study aimed to evaluate and compare the diagnostic accuracy and reliability of the subjective grading and computer-aided approach in assessing intranodal vascularity for the differentiation of benign and malignant lymph nodes. MATERIALS AND METHODS: The present study retrospectively assessed 99 power Doppler ultrasound images of cervical lymph nodes and evaluated the degree of intranodal vascularity using qualitative subjective grading (QSG) and quantitative computer-aided (QCA) methods. The diagnostic accuracy of the two methods in distinguishing metastatic and reactive nodes and their inter- and intra-rater reliability in assessing intranodal vascularity were evaluated and compared. RESULTS: The results showed that the QCA method was more accurate than the QSG method with a significantly higher sensitivity (67.8 % and 61.9 %, respectively, p < 0.05) and specificity (73.3 % and 57.3 %, respectively, p < 0.05). Using the intranodal vascularity index as determined by the QCA approach, the optimum cut-off to differentiate metastatic and reactive cervical lymph nodes was 32 %. The QCA method showed higher inter- and intra-rater reliability than the QSG method. CONCLUSION: In the assessment of the degree of intranodal vascularity, the QCA method was more accurate and reliable than the QSG method in distinguishing metastatic and reactive lymph nodes.

Shear Wave Elastography--A New Quantitative Assessment of Post-Irradiation Neck Fibrosis.

PURPOSE: Shear wave elastography (SWE) is a new technique which provides quantitative assessment of soft tissue stiffness. The aim of this study was to assess the reliability of SWE stiffness measurements and its usefulness in evaluating post-irradiation neck fibrosis. MATERIALS AND METHODS: 50 subjects (25 patients with previous radiotherapy to the neck and 25 sex and age-matched controls) were recruited for comparison of SWE stiffness measurements (Aixplorer, Supersonic Imagine). 30 subjects (16 healthy individuals and 14 post-irradiated patients) were recruited for a reliability study of SWE stiffness measurements. SWE stiffness measurements of the sternocleidomastoid muscle and the overlying subcutaneous tissues of the neck were made. The cross-sectional area and thickness of the sternocleidomastoid muscle and the overlying subcutaneous tissue thickness of the neck were also measured. The post-irradiation duration of the patients was recorded. RESULTS: The intraclass correlation coefficients for the intraoperator and interoperator reliability of deep and subcutaneous tissue SWE stiffness ranged from 0.90-0.99 and 0.77-0.94, respectively. The SWE stiffness measurements (mean +/- SD) of deep and subcutaneous tissues were significantly higher in the post-irradiated patients (64.6 ± 46.8 kPa and 63.9 ± 53.1 kPa, respectively) than the sex and age-matched controls (19.9 ± 7.8 kPa and 15.3 ± 8.37 respectively) (p < 0.001). The SWE stiffness increased with increasing post-irradiation therapy duration in the Kruskal Wallis test (p < 0.001) and correlated with muscle atrophy and subcutaneous tissue thinning (p < 0.01). CONCLUSION: SWE is a reliable technique and may potentially be an objective and specific tool in quantifying deep and subcutaneous tissue stiffness, which in turn reflects the severity of neck fibrosis.

White matter hyperintensities and quality of life in acute lacunar stroke.

White matter hyperintensities (WMH) are common in stroke. The influence of WMH on health-related quality of life (HRQoL) following a lacunar stroke is unknown. This study evaluated the impact of WMH on HRQoL in acute lacunar stroke. A cohort of 160 patients with acute lacunar stroke admitted to the stroke unit of a university-affiliated regional hospital in Hong Kong was recruited. Three months after the index stroke, a research assistant administered the Short Form-36 (SF-36) to assess HRQoL. The severity of WMH was evaluated with magnetic resonance imaging (MRI). In univariate analysis, the severity of deep WMH (DWMH) negatively correlated with patients' vitality (VT; p < 0.05), social function (SF; p < 0.001), role-emotional (RE; p < 0.01), mental health (MH; p < 0.01), and mental component summary (MCS; p < 0.001) scores of HRQoL. DWMH was independently associated with all of the above five SF-36 scores (p < 0.05) in linear regression analysis. These findings suggest that DWMH has a significant impact on the HRQoL of stroke survivors. The importance of DWMH in the long-term HRQoL in lacunar stroke warrants further investigation.

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.

Use of end-cutting needles in ultrasound-guided biopsy of neck lesions.

UNLABELLED: The management of a neck mass is dictated by its nature, location and extent. Pathological diagnosis by fine needle aspiration cytology (FNAC) or core biopsy is often required before proceeding to definitive treatment. It is not uncommon for the cytology result to come back as inadequate for various reasons. The unique design of the end-cutting biopsy needle in our experience makes it a good choice for use in obtaining both transcutaneous and intraoral biopsy under ultrasound guidance of neck lesions and serves as a useful alternative or adjunct to FNAC. Although there is, as yet, only a limited evidence base about end-cutting in comparison to side-cutting needles, they carry several potential advantages. KEY POINTS: End-cutting needles are safe to use for lesions close to vital structures. End-cutting needles yield sufficient tissue samples in a single pass. End-cutting biopsy needles are a useful adjunct to FNAC.

Reliability of shear wave ultrasound elastography for neck lesions identified in routine clinical practice.

PURPOSE: To evaluate the reliability of shear wave ultrasound elastography (SWE) in the neck. MATERIALS AND METHODS: 176 neck lesions (40 thyroid, 56 lymph nodes, 46 salivary, 34 miscellaneous) identified in a routine US clinic underwent SWE by one or two blinded radiologists. For this study, SWE required the operator to acquire three 10 second dynamic colour-coded SWE cineloops per lesion, select one static image per cineloop, and place circular regions-of-interest within the entire lesion and stiffest part to generate 3 SWE measurements per static image. For logistical reasons, one radiologist evaluated all 176 lesions and the other evaluated 58 lesions. Both radiologists also reviewed 27 archived cineloops independently to assess SWE excluding practical technique. Reliability was assessed using intraclass correlation coefficients (ICCs) concordance correlation coefficients (CCCs) and coefficients of repeatability (CORs). RESULTS: Test-retest ICCs for the radiologist evaluating 176 lesions were 0.78 - 0.85 (fair-excellent agreement), CCCs were 0.85 - 0.88 (substantial agreement), and CORs were 14.9 - 36.1 kPa. For both radiologists evaluating 58 lesions, intra-rater and inter-rater ICCs were 0.65 - 0.78 and 0.72 - 0.77 respectively. For SWE excluding practical technique, inter-rater ICCs were 0.97 - 0.98 (excellent agreement). ICCs differed according to tissue, being higher in thyroid lesions than lymph nodes (p < 0.001), and higher in benign than malignant lesions (p values < 0.001). CONCLUSION: Intra- and inter-rater reliability of SWE is fair to excellent according to ICCs. SWE reliability is influenced appreciably by acquisition technique. Nevertheless, CORs for SWE are not negligible. To determine whether these results are acceptable clinically, further research is required to establish SWE stiffness values of normal and pathological tissues in the neck.

Hemorrhagic complications in a phase II study of sunitinib in patients of nasopharyngeal carcinoma who has previously received high-dose radiation.

BACKGROUND: We aimed to evaluate the safety and efficacy of single-agent sunitinib in nasopharyngeal carcinoma (NPC). METHODS: Eligible patients had progressive disease after prior platinum-based chemotherapy. Sunitinib was given as continuous once-daily dosing of 37.5 mg in 4-week cycles until progression. RESULTS: Thirteen patients were enrolled. Recruitment was stopped after two patients died of hemorrhagic events. All patients had previously received curative radiotherapy (RT) to nasopharynx/neck (including nine patients who had chemoradiotherapy). Patients received a median of three cycles of sunitinib. One patient was still on sunitinib with stable disease after 24 cycles. Hemorrhagic events occurred in nine patients (64%), including epistaxis in six, hemoptyses in three and hematemesis in two patients. Prior RT to thorax was significantly associated with hemoptyses (P = 0.03). Two patients with local tumor invasion into the carotid sheath developed fatal epistaxis/hematemesis within the first cycle of sunitinib, likely due to internal carotid blowout after tumor shrinkage. CONCLUSIONS: Sunitinib demonstrated modest clinical activity in heavily pretreated NPC patients. However, the high incidence of hemorrhage from the upper aerodigestive tract in NPC patients who received prior high-dose RT to the region is of concern. Direct vascular invasion by tumors appeared to increase the risk of serious bleeding.

Relationship between gender, bone mineral density, and disc degeneration in the lumbar spine: a study in elderly subjects using an eight-level MRI-based disc degeneration grading system.

UNLABELLED: The study cohort comprised 196 females and 163 males. Lumbar spine bone mineral density (BMD) and magnetic resonance imaging (MRI) were acquired. Females had more severe disc degeneration than males. Lumbar spine lower BMD was associated with less severe disc degeneration. Lumbar disc spaces were more likely to be narrower when vertebral BMD was higher. INTRODUCTION: The purpose of this paper is to study the relationship between gender, BMD, and disc degeneration in the lumbar spine. METHODS: The study cohort comprised 196 females and 163 males (age range 67-89 years) with no age difference between the two groups. Lumbar spine BMD was measured with dual X-ray densitometry, and MRI was acquired at 1.5 T. A subgroup of 48 males had additional lumbar vertebral quantitative computerized tomography densitometry. Lumbar disc degeneration was assessed using a MRI-based eight-level grading system. RESULTS: Female subjects had more severe disc degeneration than male subjects. After removing age effect, a positive trend was observed between T-score and severity of lumbar disc degeneration. This was significant in female subjects while not significant in male subjects. Lumbar disc spaces were more likely to be narrowed when vertebral BMD was higher. These observations were more significant in the midlumbar region (L3/4 and L4/5) and less so at the thoracolumbar junction. CONCLUSION: Female subjects tended to have slightly more severe lumbar disc degeneration than male subjects. Lower lumbar spine BMD was associated with less severe disc degeneration.

An imaging checklist for pre-FESS CT: framing a surgically relevant report.

The reference standard for preoperative imaging in functional endoscopic sinus surgery (FESS) is multiplanar high-resolution computed tomography (HRCT). Surgeons require a precise preoperative anatomical road map, and hence it is essential for radiologists to be familiar with the normal three-dimensional sinonasal anatomy and the normal variants encountered in this region. Sagittal imaging has recently emerged as an important tool to visualize additional details in this critical anatomical region. Radiologists also need to report these examinations with special focus on the surgeon's expectations. Constant communication between the radiologist and the surgeon helps to resolve specific issues and improve the overall quality of reports. This results in better preoperative patient counselling and in predicting postoperative improvement in clinical status. This review provides a basic structured format for reporting pre-FESS CT, which can be tailored to meet individual requirements. The CT reporting format follows the order in which the sinonasal structures are approached during surgery.

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.

Cerebral microbleeds and quality of life in acute ischemic stroke.

This study evaluated the impact of cerebral microbleeds (CMBs) on the health-related quality of life (HRQoL) in 458 Chinese patients with first or recurrent acute ischemic stroke. HRQoL was assessed with the Short Form-36 (SF-36). Univariate analysis showed the presence of lobar CMBs to be negatively correlated with patients' physical functioning (PF; p < 0.01), social function (SF; p < 0.01), and role-emotional (RE; p < 0.05) scores. Subsequent linear regression analysis revealed lobar CMBs to be independently associated with the PF and SF scores (p < 0.05). The limitations of this study include the exclusion of patients with more severe stroke, the lack of longitudinal assessments, the use of a generic rather than stroke-specific HRQoL scale, and the less than optimal sensitivity of the CMB measurement. The study findings suggest that CMBs have a significant impact on the HRQoL of stroke survivors.

An uncommon cause of recurrent falls in an elderly man.

Falls are common among the elderly population. Examinations for the cause of falls are usually mundane, but may be challenging, leading to surprising diagnoses. We report on a previously healthy elderly man who presented with repeated falls and rapidly progressive limitations in mobility, in addition to a stutter. Neuroimaging was particularly helpful for making the diagnosis in this patient.

Tuberculosis in the head and neck--a forgotten differential diagnosis.

The aim of the present review is to illustrate the pathogenesis and imaging findings of tuberculosis in specific head and neck regions to avoid pitfalls in diagnosis. It is imperative to be aware of, and provide an early diagnosis for, extra-pulmonary tubercular lesions in the head and neck. A high index of suspicion combined with an appropriate clinical setting serves as an important background to diagnose tubercular lesions in the head and neck region and differentiate them from malignancy and other disease entities. Early diagnosis and treatment can prevent irreversible and debilitating complications and mortality from disseminated tuberculosis.

Microbleeds and post-stroke emotional lability.

OBJECTIVE: The clinical significance of microbleeds (MBs) in the development of psychiatric conditions following a stroke is unknown. Lesions located in various cortical and subcortical areas are thought to be involved in the pathophysiology of post-stroke emotional lability (PSEL). This study examined the association between PSEL and MBs. METHODS: A total of 519 Chinese patients with acute ischaemic stroke consecutively admitted to the acute stroke unit of a university affiliated regional hospital in Hong Kong were screened for PSEL 3 months after their index stroke. The number and location of MBs were evaluated with MRI. RESULTS: According to Kim's criteria, 74 (14.3%) patients had PSEL. In comparison with the non-PSEL group, patients in the PSEL group were more likely to have MBs in the thalamus as a whole (16.2% vs 6.5%; p = 0.004), its anterior (6.9% vs 2.0%, p = 0.02) and paramedian territories (8.1% vs 3.1%; p = 0.04), and a higher number of MBs in the entire brain (1.7+3.4 vs 1.3+5.0; p = 0.031). MBs in the thalamus remained an independent predictor of PSEL in the multivariate analysis, with an odds ratio of 4.7 (p = 0.002). CONCLUSION: Our results suggest that MBs in the thalamus may play a role in the development of PSEL. The importance of MBs in PSEL and other psychiatric conditions in stroke survivors warrants further investigation.

Tissue characterization using terahertz pulsed imaging in reflection geometry.

Terahertz pulsed imaging (TPI) is a non-ionizing and non-destructive imaging technique that has been recently used to study a wide range of biological materials. The severe attenuation of terahertz radiation in samples with high water content means that biological samples need to be very thin if they are to be measured in transmission geometry. To overcome this limitation, samples could be measured in reflection geometry and this is the most feasible way in which TPI could be performed in a clinical setting. In this study, we therefore used TPI in reflection geometry to characterize the terahertz properties of several organ samples freshly harvested from laboratory rats. We observed differences in the measured time domain responses and determined the frequency-dependent optical properties to characterize the samples further. We found statistically significant differences between the tissue types. These results show that TPI has the potential to accurately differentiate between tissue types non-invasively.

Pitfalls in interpreting rat knee joint magnetic resonance images and their histological correlation.

BACKGROUND: Magnetic resonance (MR) imaging has been increasingly used as an investigational tool for assessing the structure and function of animal joint disease models, while to date MR tomographic knowledge of laboratory animal skeletal microanatomy remains limited. PURPOSE: To describe pitfalls in interpreting rat knee joint MR images and their histological correlation. MATERIAL AND METHODS: MR scans of the right knee of five 3-month-old Sprague-Dawley (SD) rats were carried out using a 4.7T magnet, using a fat-suppressed three-dimensional (3D) gradient echo sequence with a spatial resolution of 59 x 117 x 234 microm. Histology assessment with hematoxylin and eosin staining and Safranin O staining was carried out in the five 3-month-old SD rats and two SD rats of 1 month and 6 months old, respectively. MR images were analyzed by a radiologist, and histology data were assessed by a radiologist and a pathologist. RESULTS: Though the MR images were acquired in normal rats, many signs unfamiliar to radiologists were noted, including notch-like bright signal areas in the epiphysis, gray signal areas in the epiphysis, and fuzzy joint surface of the epiphysis of the femur and tibia. Detailed inspection of the histology specimen showed more unfamiliar features of rat knee microanatomy, including curvy or dipped surface of the femur/tibia epiphysis, areas composed of a mixture of cartilage and bone components, normal notch structure, cyst-like structure, and cavity between cortical lamellae under the joint cartilage. CONCLUSION: There are a number of normal microstructures of the rat knee joint that can be potentially misinterpreted as arthritic changes on MR images. Recognizing these rat knee microstructures can help correct image reading during biomedical research.

Association of general and abdominal obesities and metabolic syndrome with subclinical atherosclerosis in asymptomatic Chinese postmenopausal women.

OBJECTIVE: This study aimed to investigate the relationships between obesity, especially abdominal obesity, andmetabolic syndrome (MS) with carotid intima-media thickness (IMT) and plaque, markers of subclinical atherosclerosis, in asymptomatic Chinese postmenopausal women in Hong Kong. DESIGN: A total of 518 postmenopausal women aged 50 to 64 years were recruited through random telephone dialing. Body mass index (BMI), waist circumference, waist-to-hip ratio, sociodemographic characteristics, blood pressures, medical, biochemical and lifestyle factors were obtained. MS was defined on the basis of the National Cholesterol and Education Program, Adult Treatment Panel III criteria. Subclinical atherosclerosis was determined by measuring IMT and plaque using high-resolution B-mode ultrasonography. RESULTS: Women with a BMI of 25 kg/mor greater, a waist circumference of 80 cm or greater, a waist-to-hip ratio of 0.85 or greater, or MS were observed to have higher IMT values and prevalence of plaque. Multivariate analyses revealed that waist circumference was significantly associated with IMT independent of age, hormone therapy, lifestyle and sociodemographic factors, and BMI (P < 0.05), whereas a waist-to-hip ratio of 0.85 or greater was significantly associated with plaque (odds ratio = 1.7; 95% CI: 1.0-2.8) after controlling for age, hormone therapy, lifestyle and sociodemographic factors, BMI, and the traditional cardiovascular risk factors. MS was also associated with IMT after adjustment for age, hormone therapy, lifestyle and sociodemographic factors, and BMI (P < 0.05), whereas its association with plaque was also significant (odds ratio = 1.7; 95% CI: 1.0-2.6) after controlling for age. CONCLUSIONS: Abdominal obesity and MS are independent of general obesity markers of subclinical atherosclerosis in Chinese postmenopausal women.

Imaging of salivary gland tumours.

Salivary gland neoplasms account for <3% of all tumors. Most of them are benign and parotid gland is the commonest site. As a general rule, the smaller the involved salivary gland, the higher is the possibility of the tumor being malignant. The role of imaging in assessment of salivary gland tumour is to define intra-glandular vs. extra-glandular location, detect malignant features, assess local extension and invasion, detect nodal metastases and systemic involvement. Image guided fine needle aspiration cytology provides a safe means to obtain cytological confirmation. For lesions in the superficial parotid and submandibular gland, ultrasound is an ideal tool for initial assessment. These are superficial structures accessible by high resolution ultrasound and FNAC which provides excellent resolution and tissue characterization without a radiation hazard. Nodal involvement can also be assessed. If deep tissue extension is suspected or malignancy confirmed on cytology, an MRI or CT is mandatory to evaluate tumour extent, local invasion and perineural spread. For all tumours in the sublingual gland, MRI should be performed as the risk of malignancy is high. For lesions of the deep lobe of parotid gland and the minor salivary glands, MRI and CT are the modalities of choice. Ultrasound has limited visualization of the deep lobe of parotid gland which is obscured by the mandible. Minor salivary gland lesions in the mucosa of oral cavity, pharynx and tracheo-bronchial tree, are also not accessible by conventional ultrasound. Recent study suggests that MR spectroscopy may differentiate malignant and benign salivary gland tumours as well as distinguishing Warthin's tumor from pleomorphic adenoma. However, its role in clinical practice is not well established. Similarly, the role of nuclear medicine and PET scan, in imaging of parotid masses is limited. Sialography is used to delineate the salivary ductal system and has limited role in assessment of tumour extent.