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Paper 1
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
Mega cisterna magna is usually an incidental diagnosis which causes the appearances of a cystic midline posterior fossa lesion located posteriorly and displacing the cerebellum. It follows cerebrospinal fluid (CSF) on all MRI sequences. An arachnoid cyst would be another possible differential as it has the same signal characteristics, although the position is suggestive of mega cisterna magna. This appearance can be detected antenatally and in these cases can be associated with infections such as cytomegalovirus or chromosomal abnormalities.
Preoperative Ultrasound Imaging in Fibroid Uterus
Published in Rooma Sinha, Arnold P. Advincula, Kurian Joseph, FIBROID UTERUS Surgical Challenges in Minimal Access Surgery, 2020
Mamata Deenadayal, Anupama Deenadayal, Hema Desai, Aarti Deenadayal Tolani
MRI is the preferred method for accurately characterizing pelvic masses (Weinreb et al. 1990). Submucosal, intramural, and subserosal fibroids, including the small fibroids and cervical location, are well demonstrated. MRI should be considered when there are more than five fibroids or the uterus is larger than 375 cc. The diagnosis of uterine leiomyomas on USG is usually reasonably straightforward, although focal adenomyosis can mimic a leiomyoma and a pedunculated uterine leiomyoma sometimes can be mistaken for an adnexal mass (Weinreb et al. 1990). When there is doubt about the origin of a pelvic mass at USG, further evaluation with MRI should be carried out. MRI sequences should include axial and sagittal T1W and T2W images (Rha et al. 2003).
Functional imaging and emerging techniques in MRI
Published in Anju Sahdev, Sarah J. Vinnicombe, Husband & Reznek's Imaging in Oncology, 2020
Roberto García-Figueiras, Anwar Padhani, Sandra Baleato-González
MRI sequences allow the evaluation of multiple parameters (T1, T2, T2*, or proton density fat fraction values and T1rho mapping) in lesions or tissues, which may enable their differentiation/characterization. This multiparametric approach has been mainly applied in liver imaging (104) (Figure 42.16) but may have value in other anatomical areas (105–108).
Alveolar bone measurements in magnetic resonance imaging compared with cone beam computed tomography: a pilot, ex-vivo study
Published in Acta Odontologica Scandinavica, 2023
João Marcus de Carvalho e Silva Fuglsig, Brian Hansen, Lars Schropp, Donald R. Nixdorf, Ann Wenzel, Rubens Spin-Neto
Magnetic resonance imaging (MRI) has become an indispensable diagnostic modality in medicine for soft-tissue-related diagnosis and treatment planning [6,7]. However, diagnosis and treatment planning in implant dentistry depends mostly on the accurate presentation of the mineralized tissues, including bone [8]. Spatial resolution of current in vivo MRI techniques is inferior to CBCT [8,9]. An MRI sequence is a number of radiofrequency pulses and gradients that produces images with a particular contrast. Most often, the signal obtained in MRI is generally obtained from matter with slower magnetisation decay than crystalline tissues (i.e. mineralized components from bone) [10]. The depiction of crystalline tissue may be possible with a few dedicated imaging sequences, including those with ultra-short echo times and even ‘zero-echo-time’ MRI (ZTE-MRI) [10]. These pulse sequences enable the visualisation of materials with very rapidly decaying signals and has been demonstrated to allow MRI-based bone [11] and dentine/enamel depiction [12,13].
Can hyperuricemia predict the progression risk of cerebral small vessel disease?
Published in Neurological Research, 2022
Cunsheng Wei, Xiaorong Yu, Lin Wang, Junying Jiang, Qi Dai, Yue Kang, Junrong Li, Xuemei Chen
All patients were scanned on a 3.0 T MRI scanner (Ingenia, Philips Medical Systems, Netherlands) with an 8-channel receiver array head coil during their hospitalization. Head motion and scanner noise were reduced using foam padding and earplugs. We included the standardized parameters of the MRI sequences, including T1-weighted and T2-weighted fluid-attenuated inversion recovery images and susceptibility weighted imaging (SWI). The MRI manifestations of cerebral small vessel disease are shown in Figure 2. A scale ranging from 0–4 was used to calculate the total burden of cerebral small vessel disease in patients, and the evaluation of imaging markers (WMH, lacunes, PVS and CMBs) of SVD was reported in detail in previous studies [27–29]. Briefly, one point was awarded for each of the following items: moderate to extensive (10–25 or >25) PVS in the basal ganglia (1 point if present); ≥1 lacune (1 point if present); periventricular WMH Fazekas score 3 or, if deep WMH, Fazekas score 2 or 3 (1 point if present); and ≥1 deep CMB (1 point if present) [27,30]. All patients underwent at least two MRI examinations during the study, and the total burden of SVD was evaluated in each MRI examination. The patients were divided into two groups according to whether their total burden of cerebral small vessel disease scores increased or not during follow-up, with SVD progression (increased by at least one point) or without SVD progression (increased by 0 points).
Clinical features and diagnostic tools in idiopathic inflammatory myopathies
Published in Critical Reviews in Clinical Laboratory Sciences, 2022
Konstantinos I. Tsamis, Constantinos Boutsoras, Evripidis Kaltsonoudis, Eleftherios Pelechas, Ilias P. Nikas, Yannis V. Simos, Paraskevi V. Voulgari, Ioannis Sarmas
Like EMG, imaging modalities are also not included in the new classification criteria for IIMs because of lack of availability [22]. However, MRI has been successfully used to evaluate diverse muscle diseases, while it has provided valuable information to direct muscle biopsy since an affected muscle with no extensive degeneration or fatty substitution is more likely to demonstrate the histologic findings of the disease [44]. The MRI sequences that are typically used in muscles are T1, which highlights fat within the tissues, T2, which highlights both fat and water, and STIR, which suppresses the signal from fat. The main MRI finding in patients with IIMs is edema, but also fatty infiltration can be observed in cases with chronic disease. Edema is synonymous with the inflammatory process and is described as areas of high signal intensity using fat suppression in T2-weighted and short-tau inversion recovery (STIR) sequences and reduced signal intensity in T1-weighted sequences. Fatty infiltration is the result of the chronic disease, and it is described as high signal intensity areas using T1 and T2-weighted sequences and decreased STIR signal [45,46]. On ultrasound, inflamed muscles appear more echogenic, highlighting the value of the method as an inexpensive alternative for the evaluation of muscle disease [46].