Detection of multiple sclerosis lesions in the cervical cord: which of the MAGNIMS 'mandatory' non-gadolinium enhanced sagittal sequences is optimal at 3T?

BACKGROUND AND PURPOSE: The magnetic resonance imaging in multiple sclerosis consensus guidelines currently mandate three sagittal non-contrast enhanced sequences of T2-weighted fast spin echo, proton density-weighted fast spin echo and short tau inversion recovery; however, these particular three sequences have not previously been compared at 3T. This study compared T2-weighted fast spin echo, proton density-weighted fast spin echo, short tau inversion recovery as well as the double inversion recovery sequence for the sagittal detection of multiple sclerosis lesions in the cervical spinal cord at 3T. METHODS: Nineteen multiple sclerosis patients underwent magnetic resonance imaging with 3T sagittal T2-weighted fast spin echo, proton density-weighted fast spin echo, short tau inversion recovery and double inversion recovery between November 2012 and April 2013. Two neuroradiologists independently reviewed the images, and the number of lesions detected on each sequence was recorded. Lesion conspicuity was quantitatively assessed with the lesion-to-cord-contrast ratio and lesion contrast-to-noise ratio. The Wilcoxon signed rank test was performed for statistical analysis. RESULTS: Proton density-weighted fast spin echo and short tau inversion recovery detected 32% more lesions compared to T2-weighted fast spin echo, and 37% more lesions compared to double inversion recovery. The lesion-to-cord-contrast ratio was highest in short tau inversion recovery, while the lesion contrast-to-noise ratio was highest for proton density-weighted fast spin echo. CONCLUSIONS: This study provides the necessary evidentiary support at 3T for the magnetic resonance imaging in multiple sclerosis spinal magnetic resonance imaging protocol consensus guidelines. At 3T sagittal proton density-weighted fast spin echo and short tau inversion recovery sequences allowed improved detection of cervical spinal cord multiple sclerosis lesions, compared to T2-weighted fast spin echo and three-dimensional double inversion recovery magnetic resonance imaging. Utilising T2-weighted fast spin echo alone at 3T is insufficient for lesion detection.

(68)Ga-DOTATATE and (18)F-FDG PET/CT in Paraganglioma and Pheochromocytoma: utility, patterns and heterogeneity.

BACKGROUND: Pheochromocytomas (PCC) and paragangliomas (PGL) are neuroendocrine tumours arising from pluripotent neural crest stem cells and are associated with neurons of the autonomic nervous system. PCCs/PGLs are often hereditary and multifocal, and their biologic behaviour and metabolic activity vary making imaging of these tumours challenging. The imaging gold standard has been I-123 MIBG complemented by CT or MRI. PGLs being neuroendocrine tumours express somatostatin receptors enabling imaging with Ga-68 DOTA-coupled peptides such as DOTATATE. Imaging with F-18 FDG also provides additional information regarding metabolic activity and biologic aggressiveness of these tumours, or, in some situations, reflecting metabolic reprogramming of these tumours. We report our experience using both Ga-68 DOTATATE and F-18 FDG PET/CT imaging in patients with PGLs and PCCs. METHODS: This was a retrospective review of 23 patients with proven PGL/PCC who underwent both DOTATATE and FDG PET/CT. Seven patients also had I-123 MIBG SPECT/CT and 1 patient had I-124 MIBG PET/CT. Lesional intensity and patterns of uptake were analysed. RESULTS: DOTATATE and FDG were positive at most sites of disease (96.2 % vs 91.4 %), although uptake intensity was significantly higher on DOTATATE with a median SUV of 21 compared to 12.5 for FDG (p < 0.001). SUVmax on F-18 FDG was significantly higher (p < 0.001) in clinically aggressive cases. I-123/I-124 MIBG detected fewer lesions (30.4 %). CONCLUSION: Overall, Ga-68 DOTATATE PET/CT detected similar number but has significantly greater lesion-to-background contrast compared to F-18 FDG PET/CT. Combined with high specificity, patient convenience and relatively low cost, DOTATATE PET/CT should be considered the ideal first line investigation for imaging PGL/PCC. Depending on DOTATATE findings and the clinical question, FDG and MIBG remain useful and, in selected cases, may provide more accurate staging, disease characterisation and guide treatment choices.

A Case Report of High 18F-FDG PET/CT Uptake in Progressive Transformation of the Germinal Centers.

Progressive transformation of the germinal centers (PTGC) is a benign reaction pattern in lymph nodes. An association with Hodgkin disease (HD) has been reported and PTGC may precede, coexist, or present after the diagnosis of HD. This case report describes a patient who presented with unprovoked pulmonary embolism and subsequent investigations showed a solitary abdominal mass, which was subsequently proven to be PTGC. PTGC is usually avid on fluorine-18-labeled fluorodeoxyglucose positron emission tomography with computed tomography for attenuation correction and may be mistaken for neoplastic disease. Being a reactive etiology, the metabolic activity is generally low with a low maximum standardized uptake value (SUVmax), but in our case, the metabolic activity and corresponding SUVmax were relatively high making the diagnosis difficult, as most clinicians would consider a high metabolically active process more likely malignant. Recognition of PTGC is important, as it is not a malignant process. Owing to its reported associations, however, patients with this diagnosis will likely require regular surveillance.

Intravascular small cell neuroendocrine tumor in the neck.

A 40-year-old man presented with a painless enlarging right neck mass over several weeks without a history of trauma or infection. Ultrasound, contrast-enhanced CT, and MRI showed a mass in an expanded vein extending into the parotid gland. Blood-stained fine-needle aspiration biopsy demonstrated atypical lymphoid cells, but there was insufficient material for a diagnosis. The mass was intensely avid on 18F-FDG PET/CT and was suggestive of a neoplasm. Excision confirmed a mass within the external jugular vein with areas of invasion through the vessel wall. A diagnosis of small cell neuroendocrine carcinoma was made on histology.

Efficacy of patient questionnaire in predicting renal dysfunction in outpatients older than 60 years of age prior to contrast-enhanced computed tomography.

INTRODUCTION: Contrast-induced nephropathy (CIN), a common iatrogenic cause of acute renal failure, is preventable. Identification of impaired renal function prior to intravenous contrast is important. Questionnaire screening has been useful to negate the need for cumbersome and costly renal function testing on all patients prior to contrast-enhanced CT (CECT). The Royal Australian and New Zealand College of Radiologists guidelines include age older than 60 as a risk marker requiring renal function testing. The aim of this retrospective study is to assess the efficacy of the pre-CT questionnaire in identifying patients with pre-existing renal impairment even in this older than 60 age group. METHODS: All outpatients were given questionnaires containing 11 CIN risk markers prior to CECT. Radiographers documented age, gender, serum creatinine and/or estimated glomerulofiltration rate (eGFR mL/min/1.72 m(2) ) within 3 months of CT. Questionnaires of all patients older than 60 years were collated. The data was tabulated and analyzed. Incomplete questionnaires were excluded. RESULTS: 134/171 (78.4%) patients had eGFR ≥ 60 and 37/171 (21.6%) had eGFR < 60, with 31/171 (18.1%) having eGFR between 30 and 60 and 3/171 (1.8%) having eGFR < 30. 47/171 (27.5%) circled 'no' to all risk markers. Percentage for sensitivity is 81.1% (95% confidence interval (CI) 64.8-92%), for specificity 29.9% (95% CI 22.3-38.4%), for positive predictive value 24.2% (95% CI 17-32.7%) and for negative predictive value 85.1% (95%CI 71.7-93.8%). Kidney disease, anaemia, myeloma and vasculitis seem to be statistically significant risk factors (P < 0.05). All three true-positive patients with eGFR < 30 indicated known kidney disease. Seven false-negative patients had eGFR 30-60, with 4/7 (57.1%) having CIN risk markers in their medical records. CONCLUSION: Questionnaire screening for CIN risk has a high negative predictive value (85.1%) even in patients older than 60 years.

Non-clinical errors using voice recognition dictation software for radiology reports: a retrospective audit.

The purpose of this study is to ascertain the error rates of using a voice recognition (VR) dictation system. We compared our results with several other articles and discussed the pros and cons of using such a system. The study was performed at the Southern Health Department of Diagnostic Imaging, Melbourne, Victoria using the GE RIS with Powerscribe 3.5 VR system. Fifty random finalized reports from 19 radiologists obtained between June 2008 and November 2008 were scrutinized for errors in six categories namely, wrong word substitution, deletion, punctuation, other, and nonsense phrase. Reports were also divided into two categories: computer radiography (CR = plain film) and non-CR (ultrasound, computed tomography, magnetic resonance imaging, nuclear medicine, and angiographic examinations). Errors were divided into two categories, significant but not likely to alter patient management and very significant with the meaning of the report affected, thus potentially affecting patient management (nonsense phrase). Three hundred seventy-nine finalized CR reports and 631 non-CR finalized reports were examined. Eleven percent of the reports in the CR group had errors. Two percent of these reports contained nonsense phrases. Thirty-six percent of the reports in the non-CR group had errors and out of these, 5% contained nonsense phrases. VR dictation system is like a double-edged sword. Whilst there are many benefits, there are also many pitfalls. We hope that raising the awareness of the error rates will help in our efforts to reduce error rates and strike a balance between quality and speed of reports generated.