Radiography Imaging Techniques

HIP OBLIQUE AXIAL MRI PLANNING AND REFERENCE LINES 

Proptosis: For most of the non-vascular lesions, pseudotumor, orbital cellulitis, thyroid eye diseases orbital cysticercosis, MRI is modality of choice. However, certain facts must be kept in mind if we suspect calcification in lesion, bony erosion or hyperostosis then CT is a better option, but MRI will be a better option if we suspect extension of lesion in orbital apex, optic canal or intracranial extension. For vascular lesions such as arterio- venous malformations, orbital varix and carotico- cavernous fistulas, MRI and MRI with contrast are better options. Retinoblastoma: MRI is the better choice. However, it will not pick up calcification. Papilledema and optic neuritis: MRI is the better option. Isolated 3 rd nerve plasy: MRI with MRA to detect posterior communicating artery aneurysm, but sometimes MRA can miss aneurysm less than 5 mm in size. Multiple cranial nerve palsy: MRI is better choice. Sometimes T2* weighted images are required to study the intracranial cours...

Neutral or low-density oral contrast media are a prerequisite for good-quality CT enterography [3-5] because they maximise contrast between the lumen and enhancing small bowel wall, facilitating assessment of mucosal thickening and wall stratification/enhancement patterns [1-8]. Water–methylcellulose solution, polyethylene glycol, commercially available low-density barium, 0.1% Volumen (Bracco, Milan, Italy) and milk are examples of neutral oral contrast agents with CT attenuation properties similar to that of water. Water alone usually results in inadequate distension due to rapid reabsorption, although some authors advocate its use [9]. Use of Volumen has been shown to improve the quality of bowel distension compared with water alone [4,10-12], but it remains unlicensed for use in the UK and therefore is not available. Milk was shown to give similar results as Volumen [13], but although less expensive and freely available in Europe, it may be deemed unpalatable by many patients wh...

Germ cell tumors represent 15% to 20% of all tumors of the ovary. Dermoids account for 95% of all ovarian germ cell tumors. Most of these are unilocular, contain sebaceous fluid, and are commonly referred to as mature cystic teratomas or dermoid cysts. Although these are usually asymptomatic and are incidental findings in young women, the standard treatment is surgical removal because of their potential to cause ovarian torsion or for the cyst to rupture. There is also a rare chance of malignant degeneration to squamous cell carcinoma. Although most mature cystic teratomas can be diagnosed at ultrasound, one prospective study has shown the sensitivity to be 58% with a specificity of 99%. 11  Numerous pitfalls exist in their diagnosis by ultrasound. The presence of blood clot within a hemorrhagic cyst can appear echogenic, which causes confusion in the diagnosis. Adjacent echogenic bowel can also be mistaken for a mature cystic teratoma and vice versa. MRI has a high sensitivity f...

Because relaxation times are longer at 3.0 T than at 1.5 T, there may be decreased soft-tissue contrast and decreased lesion conspicuity on unenhanced T1-weighted images (Fig 2). To compensate, longer repetition times are required to improve soft-tissue contrast when performing high-field-strength abdominal imaging. However, longer repetition times result in a longer imaging time and are often limited by the length of the patient’s breath hold. One solution that has been used for unenhanced T1-weighted imaging at higher field strengths is incorporating an inversion recovery preparatory pulse to accentuate T1 contrast. Use of a magnetization preparation prepulse for gradient-echo imaging is also beneficial (53,54). Parallel imaging techniques also may be used to decrease overall acquisition time at T1-weighted imaging.