magnetic resonance imaging

Purpose: To determine the normal value of basal angle measured using the modified MR imaging technique in Thai population compared with the standard value obtained from the Western population. Material and Methods: We retrospectively evaluated midline sagittal SE T1 weighted MR images in 200 adults and 50 children. The basal angle of the skull base was measured using the modified MR imaging technique described by Koenigsberg et al. The angle was formed by a line extending across the anterior cranial fossa to the tip of the dorsum sellae and another line drawn along the posterior margin of the clivus. The mean values of the basal angles among different age groups and sex were calculated and analyzed. Results: The mean skull base angle of our adult population was 115° (range 100.5°-130°, SD=5.7) with an inter-observer agreement of 0.85, slightly smaller than the previous study from the USA which was 117°. There was no significant difference between the male and female groups. The mean skull base angle in our children population was 114.7° (range 102- 130.5°, SD=6.3) with an inter-observer agreement of 0.89, quite similar to the previous USA study which was 114°. There was no significant difference between adult and children. Conclusion: The mean adult skull base angle measured using the modified MR imaging technique in Thai population was slightly smaller than the Western population, while the mean skull base angle of children was quite similar. The basal angle range of 103.6°-126.4° may be used as a guide for the potential range of normal skull base angles in Thai population and possibly also the Southeast Asian population.

Background: Low back pain has recently been reported as the leading cause for disability worldwide. The diagnostic value of imaging has been estimated low. Led by own positive experience, however, we hypothesized that MRI can detect signs of facet joint pain. Methods: 15 patients and 15 controls were retrospectively assessed by two readers. They compared de-identified T2 weighted lumbar spine MRI scans. Facet joint size, shape, angle, joint space signal and degeneration were rated. Pain aetiology was proven with the diagnostic gold standard of medial branch blocks. Results: Facet joint angles and joint diameters were significantly larger in symptomatic patients, who also showed significantly higher grades of degeneration but no difference in joint space distances or shape or signal intensity. The readers were able to correctly identify symptomatic patients with good interrater reliability (kappa 0.5, sensitivity and specificity 0.87-0.93), positive (LR+= 6.7-7.2) and negative likelihood ratios (LR-=0.15). Conclusion: Contrary to recent publications, we could demonstrate differences between asymptomatic and symptomatic subjects showing the latter to have larger joints and more signs of degeneration. One can conclude from the strong LR+ and LR- values that MRI is a useful investigation to rule in or rule out facet pain.

Inferior vena cava (IVC) involvement by intraluminal extension of tumor is infrequent, occuring in 4% to 10% of patients with renal cell carcinoma (RCC) [1-5]. Based on the cephalic extension of the thrombus, Mayo [6] described a classification of inferior vena cava thrombi in 4 categories, which has implications on surgical complexity, estimated blood loss (EBL) and peri-operative complications, but not cancer-specific survival [2,7]. Level III IVC thrombus is classified as being located in the retro-hepatic IVC below the diaphragm. Total resection of this tumor is the best chance of cure when no distant metastases are present [4,8]. Actually, open radical nephrectomy with concomitant thrombectomy is still the standard treatment. This procedure is technically challenging and involves a large incision and prolonged convalescence [9]. Recently, the feasibility of robotic IVC thrombectomy has been demonstrated, with potential lower EBL and shorter hospitalization and convalescence [7,10-14]. This surgery requires thorough knowledge of surgical anatomy, detailed pre-operative preparation and meticulous robotic technique [7]. The key point in the surgical management is the correct assessment of the extension of the endocaval thrombus, what is mainly based on radiological examinations [8]. Although Ultrasonography (US) and computerized tomography (CT) are useful in demonstrating the extent of the thrombus, CT is not always accurate in delineating the superior margin of the tumor in the IVC. More precisely, magnetic resonance imaging (MRI) can demonstrate a tumor thrombus and its extension, besides signs of wall invasion, being extremely useful to surgical procedure planning [8,15]. Vena cavography is not additive to US, CT, and MRI, and it increases the risk of contrast-associated renal injury [4,8]. However, new modern image technologies has emerged to help surgical planning, as three-dimensional visualization technique (3DVT) based on routine CT or MRI processed image data [16-20]. Recently, a comparative study showed advantage of 3DVT in management of complex renal tumor during laparoscopic partial nephrectomy [20]. This modality is able to demonstrate anatomy relations, allowing the surgeon to observe the relationship between targeted tumor and peripheral structure before surgery and perform virtual manipulation. This kind of preoperative accurate assessment can enhance surgeons confidence of surgical procedure and decrease surgical risk and incidence of complications [20]. There is no report in the literature of the use of this type of technology in cases of IVC tumor thrombus. We present the use of 3D holographic interactive reconstruction in a single case of robotic radical nephrectomy with level III IVC thrombectomy.

Vestibular disorders and anxiety are closely related, probably because they share some neuronal pathways. Ageing and patient comorbidities are important facilitating factors, and multiple vascular risk factors could contribute to the onset of a vestibular syndrome called vascular vertigo. White matter lesions (WML) are often seen on magnetic resonance imaging (MRI) scans of elderly people and are related to various geriatric disorders, including dizziness. The cause of this correlation could be the disruption of neuronal networks that mediate higher vestibular cortical function. Numerous neuronal pathways link the vestibular network with limbic structures and the prefrontal cortex modulates anxiety through its connections to amygdala. The aim of the present work was to investigate the correlation between WML, amygdala and cognitive functions.

Cancer metastasis to the pituitary gland is rare, but in most cases, it originates from a late-stage breast tumor or lung cancer. The most common symptoms of metastasis to the pituitary gland are diabetes insipidus and visual disturbance. The common site of metastasis is the posterior portion of the pituitary gland because it is highly vascularized. Metastases to this site represent 1% of all tumors [1]. Metastasis to the pituitary gland is difficult to diagnose by hormonal analysis and magnetic resonance imaging of the brain and requires biopsy for confirmation [2].