Accuracy of dopaminergic imaging as a biomarker for mild cognitive impairment with Lewy bodies.

BACKGROUND: Dopaminergic imaging is an established biomarker for dementia with Lewy bodies, but its diagnostic accuracy at the mild cognitive impairment (MCI) stage remains uncertain. AIMS: To provide robust prospective evidence of the diagnostic accuracy of dopaminergic imaging at the MCI stage to either support or refute its inclusion as a biomarker for the diagnosis of MCI with Lewy bodies. METHOD: We conducted a prospective diagnostic accuracy study of baseline dopaminergic imaging with [123I]N-ω-fluoropropyl-2ß-carbomethoxy-3ß-(4-iodophenyl)nortropane single-photon emission computerised tomography (123I-FP-CIT SPECT) in 144 patients with MCI. Images were rated as normal or abnormal by a panel of experts with access to striatal binding ratio results. Follow-up consensus diagnosis based on the presence of core features of Lewy body disease was used as the reference standard. RESULTS: At latest assessment (mean 2 years) 61 patients had probable MCI with Lewy bodies, 26 possible MCI with Lewy bodies and 57 MCI due to Alzheimer's disease. The sensitivity of baseline FP-CIT visual rating for probable MCI with Lewy bodies was 66% (95% CI 52-77%), specificity 88% (76-95%) and accuracy 76% (68-84%), with positive likelihood ratio 5.3. CONCLUSIONS: It is over five times as likely for an abnormal scan to be found in probable MCI with Lewy bodies than MCI due to Alzheimer's disease. Dopaminergic imaging appears to be useful at the MCI stage in cases where Lewy body disease is suspected clinically.

Evolving role of positron emission tomography (PET) in urological malignancy.

We present a review on the increasing indications for the use of positron emission tomography (PET) in uro-oncology. In this review we describe the details of the different types of PET scans, indications for requesting PET scans in specific urological malignancy and the interpretation of the results.

Incidentalomas in the head & neck.

Incidental findings (IFs) in the head & neck are a frequent challenge to the reporting radiologist. A combination of complex anatomy, widely varied imaging techniques and the high prevalence of benign pathology, makes safe and appropriate management of head & neck IFs problematic. The non-head & neck radiologist is unlikely to have prior personal experience of the relevant specialties or current involvement with the pertinent multidisciplinary teams, creating unfamiliarity with both the clinical aspects of head & neck disease and the value of examination techniques. This triumvirate of complex anatomy, pathology and imaging creates the perfect environment for excessive investigation and overdiagnosis. In this article, the most frequently encountered and clinically relevant head & neck IFs are summarised. To reflect daily clinical practice, we will firstly consider anatomic abnormalities identified on cross-sectional imaging and ultrasound, followed by a review of PET-CT incidental findings.

The application of radiomics in laryngeal cancer.

OBJECTIVES: Radiomics is the conversion of medical images into quantitative high-dimensional data. Laryngeal cancer, one of the most common head and neck cancers, has risen globally by 58.7%. CT, MRI and PET are acquired during the diagnostic process providing potential data for radiomic analysis and correlation with outcomes.This review aims to examine the applications of this technique to laryngeal cancer and the future considerations for translation into clinical practice. METHODS: A comprehensive systematic review-informed search of the MEDLINE and EMBASE databases was undertaken. Keywords "laryngeal cancer" OR "larynx" OR "larynx cancer" OR "head and neck cancer" were combined with "radiomic" OR "signature" OR "machine learning" OR "artificial intelligence". Additional articles were obtained from bibliographies using the "snowball method". RESULTS: The included studies (n = 15) demonstrated that radiomic features are significantly associated with various clinical outcomes (including stage, overall survival, treatment response, progression-free survival) and that predictive models incorporating radiomic features are superior to those that do not. Two studies demonstrated radiomics could improve laryngeal cancer staging whilst 12 studies affirmed its predictive capability for clinical outcomes. CONCLUSIONS: Radiomics has potential for improving multiple aspects of laryngeal cancer care; however, the heterogeneous cohorts and lack of data on laryngeal cancer exclusively inhibits firm conclusions. Large prospective well-designed studies in laryngeal cancer are required to progress this field. Furthermore, to implement radiomics into clinical practice, a unified research effort is required to standardise radiomics practice. ADVANCES IN KNOWLEDGE: This review has highlighted the value of radiomics in enhancing laryngeal cancer care (including staging, prognosis and predicting treatment response).

Accuracy of Cardiac Innervation Scintigraphy for Mild Cognitive Impairment With Lewy Bodies.

OBJECTIVE: To provide evidence that cardiac I-123-metaiodobenzylguanidine sympathetic innervation imaging (MIBG) scintigraphy differentiates probable mild cognitive impairment with Lewy bodies (MCI-LB) from mild cognitive impairment due to Alzheimer disease (MCI-AD), we scanned patients with MCI and obtained consensus clinical diagnoses of their MCI subtype. We also performed baseline FP-CIT scans to compare the accuracy of MIBG and FP-CIT. METHODS: We conducted a prospective cohort study into the accuracy of cardiac MIBG scintigraphy in the diagnosis of MCI-LB. Follow-up clinical assessment was used to diagnose MCI-AD (no core features of MCI-LB and normal FP-CIT), probable MCI-LB (2 or more core features, or 1 core feature with abnormal FP-CIT), or possible MCI-LB (1 core feature or abnormal FP-CIT). For the comparison between MIBG and FP-CIT, only core clinical features were used for diagnosis. RESULTS: We recruited 95 people with mild cognitive impairment. Cardiac MIBG was abnormal in 22/37 probable and 2/15 possible MCI-LB cases and normal in 38/43 MCI-AD cases. The sensitivity in probable MCI-LB was 59% (95% confidence interval [CI], 42%-75%), specificity 88% (75%-96%), and accuracy 75% (64%-84%). The positive likelihood ratio was 5.1 and negative likelihood ratio 0.46. With symptom-only diagnoses, the accuracies were 79% for MIBG (95% CI, 68%-87%) and 76% for FP-CIT (95% CI, 65%-85%). CONCLUSIONS: Cardiac MIBG appears useful in early disease, with an abnormal scan highly suggestive of MCI-LB. Validation in a multicenter setting is justified. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that cardiac MIBG distinguishes MCI-LB from MCI-AD.

Spontaneous femoral shaft fracture after long-term alendronate.

Alendronate is used as first-line treatment for osteoporosis in postmenopausal women worldwide. The evidence supporting its benefit in reducing the risk of fragility fracture among this high-risk group is well established. Due to its mechanism of action, there were concerns about potential reduction in bone turnover, repair of microdamage and hence reduced bone toughness and increased risk of fractures with long-term use. A number of cases have been reported from other countries describing a pattern of atraumatic mid-femoral fractures in women on long-term alendronate therapy. We present a case of an atraumatic femoral shaft fracture in an elderly woman on long-term alendronate therapy admitted to a UK Hospital.

99m-Technetium Sestamibi Uptake in a Gastric Schwannoma.

We report the case of a 74-year-old woman with primary hyperparathyroidism who underwent 99m-technetium-sestamibi single photon emission computed tomography-computed tomography for preoperative localization of parathyroid adenoma. Unexpected focal sestamibi uptake was observed at a 5 cm submucosal tumor arising from the greater curve of the stomach. The patient underwent partial gastrectomy and the histological and immunohistochemical findings were consistent with the diagnosis of gastric schwannoma.

Intra- and interobserver variability in skeletal muscle measurements using computed tomography images.

PURPOSE: The progressive loss of skeletal muscle and function (known as sarcopenia) has been shown to be associated with various adverse outcome measures. Sophisticated measurements of body composition are increasingly being incorporated into research studies to stratify patients into those with or without sarcopenia, monitor treatment effects, and predict complications. A typical approach is to select axial image(s) at the mid-lumbar level and use semi-automated software to identify and quantify the skeletal muscle area. This area is then used to estimate whole-body parameters. This approach is somewhat subjective, and in this study we investigate its reproducibility, both within and between observers. MATERIALS AND METHODS: Repeated muscle measurements were performed on a cohort of 29 patients by 3 radiologists, to examine their intra- and interobserver reproducibility. RESULTS AND DISCUSSION: Mean muscle area for the cohort was 156 cm2, with a wide range (98 - 261 cm2). There was good intraobserver agreement between measurements, with a mean absolute difference between repeated measurements on the same patient of 0.98 cm2, and a measurement variability of 2.92 cm2. Much of the variability was shown to be due to the choice of a different slice when performing the repeated measurement. Averaging two slices provided a small but non-significant improvement in comparison to the single slice approach. Interobserver results showed good agreement, though there was a small bias for one observer, who measured slightly larger volumes compared to the other two. We conclude that the approach described provides reproducible skeletal muscle area measurements, and offer three specific recommendations to minimise variability.

Assessment of normal reference values for thyroid uptake of technetium-99m pertechnetate in a single centre UK population.

OBJECTIVE: This study aims to explore the normal reference values for thyroid uptake of technetium-99m (Tc) pertechnetate in a UK population. PATIENTS AND METHODS: A retrospective review of 60 euthyroid patients who underwent thyroid imaging with Tc pertechnetate between January 2012 to April 2014 as part of dual-tracer subtraction parathyroid scintigraphy. Tc pertechnetate thyroid uptake values were determined for each patient. Medical records and biochemical thyroid function tests were reviewed to ensure that all patients were not on medication that could affect thyroid function and they were both clinically and biochemically euthyroid 6 months before and following the scan. RESULTS: Median and interquartile uptake range of Tc pertechnetate in euthyroid patients were 0.9 and 0.5-1.4%, respectively. The normal reference range in the study population was 0.2-2.0%. Thyroid uptake inversely correlated with age in females (r=-0.40, P=0.04), males (r=-0.50, P=0.04), and whole group (r=-0.40, P=0.002). CONCLUSION: The calculated normal reference range in this study was found to be less than that used in our own and many other UK institutions. The results demonstrate the importance of periodic evaluation of normal uptake values and provide support for prospective studies defining the normal reference range to be performed.