When should we image our patients? Appropriate use of imaging in inpatient psychiatry.

OBJECTIVE: Injudicious use of medical imaging may be associated with harm to patients and increased downstream healthcare costs. Guidance on the use of imaging in common psychiatric inpatient scenarios is inconsistent or absent. This paper explores three common clinical scenarios facing adult psychiatrists and provides guidance about the appropriate use of imaging. CONCLUSION: Psychiatrists and their junior colleagues would benefit from considering both pre- and post-test probability in each presentation.

Tumour-capsule interface measured on 18F-DCFPyL PSMA positron emission tomography/CT imaging comparable to multi-parametric MRI in predicting extra-prostatic extension of prostate cancer at initial staging.

INTRODUCTION: Nerve-sparing prostatectomy is recommended in cases of organ-confined prostate cancer but is generally contraindicated in patients with suspected extra-prostatic extension (EPE). PSMA ligand imaging has been shown to be valuable in predicting EPE when performed on a hybrid PET/MRI scanner; however, the majority of PSMA PET imaging is performed using PSMA-PET. To our knowledge, there are no established PET/CT criteria for assessing EPE. In this study, we aim to provide a reproducible method for evaluating EPE on PSMA-PET/CT imaging and assess its utility compared with MRI. METHODS: Imaging findings and histopathology were reviewed for 100 consecutive patients who underwent a radical prostatectomy after imaging with MRI and 18F-DCFPyL PSMA-PET/CT. RESULTS: A broad tumour-capsule interface measured using a standardised technique on fused PSMA-PET/CT imaging is associated with a higher risk for established EPE (P < 0.001). In our cohort, applying the criteria of tumour-capsule contact ≥ 10 mm measured on PET/CT was as sensitive as applying PI-RADS version 2 criteria to mpMRI imaging for predicting EPE (74% and 79%, respectively, P = 0.11) and had superior specificity (86% and 61%, respectively, P = 0.035). 93% of MRI-occult lesions were visualised on PSMA-PET/CT. Applying the proposed PET/CT criteria for EPE to this subgroup of 14 patients yielded a sensitivity of 67% and specificity of 92%. CONCLUSION: Our results suggest that tumour-capsule interface measured on fused F18-DCFPyL PSMA-PET/CT imaging is comparable to MRI criteria for predicting the presence of EPE. Applying PET/CT criteria may be of particular benefit in predicting EPE in patients with MRI-occult prostate cancer.

Idiopathic intradural dorsal thoracic arachnoid cysts: A case series and review of the literature.

BACKGROUND: Spinal intradural arachnoid cysts (SIAC) are cerebrospinal fluid (CSF) filled sacs formed by arachnoid membranes and may be either idiopathic or acquired. Idiopathic cysts represent a separate entity and their aetiology remains uncertain. By far the most difficult differential diagnosis is distinguishing between idiopathic anterior spinal cord herniation (IASCH) and dorsal thoracic intradural arachnoid cysts (TIAC), due to their similarity in radiological appearance. Cine-mode (SSFP) is emerging as a novel technique in the diagnosis and operative planning of SIAC. METHOD: Retrospective analysis of patients with idiopathic TIACs that were surgically managed at Royal North Shore Hospital and North Shore Private Hospital between November 2000 and November 2015. RESULTS: Ten patients were included in this study. Age ranged from 20 to 77years with a mean age of 60years and a female preponderance. The most common clinical features were progressive gait ataxia and lower limb myelopathy. Radicular pain tends to improve following surgery, however gait ataxia may not. DISCUSSION: While there are circumstances in which the distinction between dorsal thoracic intradural arachnoid cysts and idiopathic anterior spinal cord herniation are radiologically obvious, in cases where the appearances are less clear, cine-mode SSFP MRI imaging can provide an invaluable tool to differentiate these pathologies and lead the clinician towards the correct diagnosis and management. The mainstay of surgical management for dorsal TIACs is laminectomy and cyst excision or fenestration. Surgery for gait ataxia should be aimed towards preventing deterioration, while maintaining the potential for symptomatic improvement, whereas surgery for radicular pain should be curative.

Lumbosacral transitional vertebrae and its prevalence in the Australian population.

Study Design Retrospective cohort study. Objective Lumbosacral transitional vertebrae (LSTV) are a common congenital anomaly, and they can be accurately identified on anteroposterior (AP) radiographs of the lumbosacral spine. This study attempts to determine the prevalence of this congenital anomaly and to increase awareness among all clinicians to reduce the risk of surgical and procedural errors in patients with LSTV. Methods A retrospective review of 5,941 AP and lateral lumbar radiographs was performed. Transitional vertebrae were identified and categorized under the Castellvi classification. Results The prevalence of LSTV in the study population was 9.9%. Lumbarized S1 and sacralized L5 were seen in 5.8 and 4.1% of patients, respectively. Conclusion LSTV are a common normal variant and can be a factor in spinal surgery at incorrect levels. It is essential that all clinicians are aware of this common congenital anomaly.