Psoas proximal insertion as a simple and reliable landmark for numbering lumbar vertebrae on MRI of the lumbar spine.

OBJECTIVE: To evaluate the value of psoas muscle proximal insertion for correct numbering of the lumbar vertebrae in MRI, in particular in case of lumbosacral transitional vertebra (LSTV). METHODS: Two radiologists assessed 477 MRI scans of the lumbar spine with a sagittal localizer sequence on the whole spine for numbering vertebrae caudally from C2. Proximal insertion of the psoas was determined as the most proximal vertebra with psoas over half of its body on coronal T2 STIR sequence. The last lumbar vertebra was named considering both its number and the presence or absence of LSTV according to Castellvi classification. These same parameters were also assessed on 207 PET-CT scans of another cohort including the whole spine. RESULTS: Proximal insertion of the psoas was L1 in 94.1% of cases: 98.5% in case of modal anatomy, 81.4% in case of LSTV, and 51.7% in case of missing or supernumerary lumbar vertebra without LSTV. There was no statistically significant difference between MRI and CT data. The inter-reader agreement for determination of psoas proximal insertion was excellent (kappa = 0.96). CONCLUSION: Proximal insertion of the psoas muscle is a helpful marker for correct numbering of the lumbar vertebrae in MRI and to detect a complete lumbosacral segmentation anomaly. KEY POINTS: • Proximal insertion of the psoas muscle can be easily identified on a coronal T2 STIR sequence. • Psoas proximal insertion on the spine almost always designates the first lumbar vertebra and is helpful to accurately number all lumbar vertebrae, especially in case of lumbosacral transitional vertebra. • Conversely, when psoas muscle does not insert five lumbar bodies above the apparent lumbosacral joint, the probability of variation in the number of lumbar vertebrae is high.

FDG PET-CT for solitary pulmonary nodule and lung cancer: Literature review.

The investigation of solitary pulmonary nodule (SPN) and non-small cell lung cancer (NSCLC) has rapidly become one of the main indications for 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), currently combined with computed tomography (PET-CT). In this literature review, we first attempt to clarify how PET imaging contributes to investigating SPN, in conjunction with conventional CT. We highlight the prospects of research underway to improve our understanding of SPN. In the second part of this review, we analyze the current role of PET-CT in the overall care process for lung cancer. We review the indications for which consensus has been reached, for example initial staging, as well as new indications such as radiation therapy planning or prognostic assessment.

Value of (18)F-FDG PET/CT for therapeutic assessment of patients with polymyalgia rheumatica receiving tocilizumab as first-line treatment.

PURPOSE: To evaluate the use of (18)F-FDG PET/CT for the assessment of tocilizumab (TCZ) as first-line treatment in patients with polymyalgia rheumatica (PMR). METHODS: Patients with PMR were prospectively enrolled in a multicentre clinical trial assessing TCZ therapy (the TENOR trial). The patients underwent FDG PET/CT at baseline, after the first infusion of TCZ (TCZ 1) and after the last infusion of TCZ (TCZ 3). Responses to treatment were evaluated in terms of the PMR activity score (PMR-AS), and the C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) laboratory tests. Maximal standardized uptake value (SUVmax) was used for assessment of FDG uptake in regions usually affected in PMR (spinous processes, hips, shoulders, sternoclavicular region and ischial tuberosities). The Wilcoxon test was applied to evaluate the changes in parameters after the infusions and Spearman's rank correlation test was applied to assess the correlations between SUVmax and PMR-AS, CRP and ESR. RESULTS: Of 21 patients included in the trial, 18 were evaluated. The median bioclinical parameter values decreased after TCZ 1 (PMR-AS from 38.2 to 15.7, CRP from 65.2 to 0.4 mg/l and ESR from 49 to 6.5 mm; all p < 0.05) as did the median SUVmax (from 5.8 to 5.2; p < 0.05). All values also decreased after TCZ 3 (PMR-AS from 38.2 to 3.9, CRP from 65.2 to 0.2, ESR from 49 to 2, and SUVmax from 5.8 to 4.7; p < 0.05). In a region-based analysis, all SUVmax were significantly reduced after TCZ 3, except the values for the cervical spinous processes and shoulder regions. With regard to correlations, few significant differences were found between ∆SUVmax and the other parameters including ∆PMR-AS, ∆CRP and ∆ESR in the patient-based and region-based analysis. CONCLUSION: FDG uptake decreased significantly but moderately after TCZ therapy in PMR patients, and might reflect disease activity.

Comparison of positron emission tomography and lymphangiography in the diagnosis of infradiaphragmatic Hodgkin's disease.

PURPOSE: To evaluate the respective roles of positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) and lymphangiography (LAG) in staging Hodgkin's disease (HD) patients with negative contrast-enhanced infradiaphragmatic computed tomography (CT). MATERIAL AND METHODS: 28 patients underwent FDG-PET and LAG at initial staging. Concordant positive findings on both tests were regarded as actual HD locations and concordant negative findings as true negative. In case of discrepancy, the reference was biopsy or magnetic resonance imaging (MRI). RESULTS: Concordant results were obtained in 26 patients (24 negative, two positive). In two of the 24 negative patients, PET showed additional lesions in the spleen and one celiac lymph node (one patient), and in the right kidney and the right iliac crest (one patient). Discordant results were obtained in two patients. Both methods indicated infradiaphragmatic involvement in different locations in one patient. In the other, PET was falsely positive (PET done within 24 hours after a negative LAG), which was confirmed by biopsy (benign inflammatory, probably due to LAG medium). CONCLUSION: FDG-PET and LAG gave comparable results, making invasive LAG unnecessary. Furthermore, LAG, when performed before PET, can be responsible for false-positive PET results.