ABSTRACT
BACKGROUND: Dual-layer spectral detector CT (SDCT) may provide several theoretical advantages over pre-existing DECT approaches in terms of adjustment-free sampling number and dose modulation, beam hardening correction, and production spectral images by post-processing. In addition, by adopting noise reduction algorithm, high contrast resolution was expected even in low keV level. We surmised that this improvement would be beneficial to obese people. Therefore, our aim of study is to compare image quality of virtual monochromatic spectral images (VMI) and polychromatic images reconstructed from SDCT with different body size and radiation dose using anthropomorphic liver phantom. METHODS: One small and one large size of body phantoms, each containing eight (four high- and four low-contrast) simulated focal liver lesions (FLLs) were scanned by SDCT (at 120 kVp) using different Dose Right Indexes (DRIs). VMI were reconstructed from spectral base images from 40 keV to 200 keV. Hybrid iterative reconstruction (iDose4) was used for polychromatic image reconstruction. Image noise and contrast to noise ratio (CNR) were compared. Five radiologists independently rated lesion conspicuity, diagnostic acceptability and subjective noise level in every image sets, and determined optimal keV level in VMI. RESULTS: Compare with conventional polychromatic images, VMI showed superior CNR at low keV level regardless of phantom size at every examined DRIs (Ps < 0.05). As body size increased, VMI had more gradual CNR decrease and noise increase than conventional polychromatic images. For low contrast FLLs in large phantom, lesion conspicuities at low radiation dose levels (DRI 16 and 19) were significantly increased in VMI (Ps < 0.05). Subjective image noise and diagnostic acceptabilities were significantly improved at VMI in both phantom size. CONCLUSIONS: VMI of dual-layer spectral detector CT with noise reduction algorithm provides improved CNR, noise reduction, and better subjective image quality in imaging of obese simulated liver phantom compared with polychromatic images. This may hold promise for improving detection of liver lesions and improved imaging of obese patients.
Subject(s)
Liver/diagnostic imaging , Obesity/diagnostic imaging , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Algorithms , Body Size , Humans , Observer Variation , Phantoms, Imaging , Radiation Dosage , Signal-To-Noise RatioABSTRACT
We report the clinical details and imaging findings for a case of vesicovaginal reflux presenting as gross urocolpos in a 15-year-old female. Findings included a large fluid-filled vagina on full-bladder scan in the absence of any anatomical abnormality, which disappeared completely after micturition. It is important for radiologists to be aware of this entity as it is rarely encountered and leads to very confusing findings, which could result in an erroneous diagnosis.
Subject(s)
Hydrocolpos/diagnostic imaging , Hydrocolpos/etiology , Urinary Bladder Diseases/complications , Urinary Bladder Diseases/diagnostic imaging , Adolescent , Diagnosis, Differential , Female , Humans , Hydrocolpos/urine , Tomography, X-Ray Computed , Urinary Bladder Diseases/urine , Urination , Vagina/diagnostic imagingABSTRACT
Congenital duplication of facial nerve is a very rare anomaly commonly associated with inner and middle ear anomalies. There can be duplication of mastoid, tympanic, or labyrinthine segments. We describe duplication of mastoid segment of facial nerve in a young female who also showed middle ear anomalies and external auditory canal atresia.
