Normative Data of the Interorbital Distance in Thai Population.

The incidence of the patients with craniofacial anomalies was high in southeast-Asian countries, for example, fronto-ethmoidal encephalo-menigocele or craniosynostosis. These craniofacial anomalies usually involve orbits, so a surgical orbital reconstruction is always required.Various methods have been used in the past to indirectly analyze the craniofacial region. Plain skull radiography, anthropometry, and cephalometry provided the limited information of interorbital distance in terms of accuracy whereas the interorbital distance is crucial to be reconstructed, increasing or decreasing. The accurate normal interorbital distance which grows by age as other craniofacial structures is the important data in the part of interorbital and orbital reconstruction. To date, the normative data of the bony interorbital distance among Thai population have not been established.The purpose of this study is to provide normal values and the growth patterns of the bony interorbital distances and other dimensions of the orbit according to age among Thai population through the axial computed tomography. Comparisons can then be made between normal values and those for an individual patient or those for a group of patients, for example, those with front-ethmoidal meningoencephalocele, Crouzon, or Treacher-Collins syndrome, or among values for individual patients at different time intervals.A retrospective study of computed tomography (CT) scan series of 698 normal orbits from 349 skeletally normal subjects (202 men and 147 women) was enrolled. The age range of the patients was 0 to 21 years (mean, 10.2 years; SD, 5.8 years). A series of 12 measurements were obtained from the CT scans of each subject. All CT images were obtained from patients who underwent CT of the facial bone, brain, and orbits at the Department of Radiology of 3 big hospital in Bangkok-Ramathibodi, Samitivej Srinakarin, and Bangkok hospital-since 2010 to 2015.The normal measurement values in the orbital region through the CT images, as the normal periorbital growth curve, will help improving diagnostic accuracy, staging of reconstruction, precision of corrective surgery, and follow-up of the Thai patients with craniofacial abnormalities such as front-ethmoidal meningoencephalocele, hypertelorism. These data may also apply to the related population in the southeast-Asian countries.

Factors Determining the Clinical Complications of Radiosurgery for AVM.

PURPOSE: To identify the predictors of symptomatic post-radiation T2 signal change in patients with arteriovenous malformations (AVM) treated with radiosurgery. MATERIALS AND METHODS: The charts of 211 consecutive patients with arteriovenous malformations treated with either gamma knife radisurgery or linear accelerator radiosurgery between 2000-2009 were retrospectively reviewed. 168 patients had a minimum of 12 months of clinical and radiologic follow-up following the procedure and complete dosage data. Pretreatment characteristics and dosimetric variables were analyzed to identify predictors of adverse radiation effects. RESULTS: 141 patients had no clinical symptomatic complications. 21 patients had global or focal neurological deficits attributed to symptomatic edema. Variables associated with development of symptomatic edema included a non-hemorrhagic symptomatic presentation compared to presentation with hemorrhage, p=0.001; OR (95%CI) = 6.26 (1.99, 19.69); the presence of venous rerouting compared to the lack of venous rerouting, p=0.031; OR (95% CI) = 3.25 (1.20, 8.80); radiosurgery with GKS compared to linear accelerator radiosurgery p = 0.012; OR (95% CI) = 4.58 (1.28, 16.32); and the presence of more than one draining vein compared to a single draining vein p = 0.032; OR (95% CI) = 2.82 (1.06, 7.50). CONCLUSIONS: We postulated that the higher maximal doses used with gamma knife radiosurgery may be responsible for the greater number of adverse radiation effects with this modality compared to linear accelerator radiosurgery. We found that AVMs with greater venous complexity and therefore instability resulted in more adverse treatment outcomes, suggesting that AVM angioarchitecture should be considered when making treatment decisions.Facteurs en cause dans les complications cliniques de la radiochirurgie pour une malformation artérioveineuse.

Angioarchitecture determines obliteration rate after radiosurgery in brain arteriovenous malformations.

BACKGROUND: Radiosurgery as a potential treatment modality for brain arteriovenous malformations (AVM) has 60% to 90% obliteration rates. OBJECTIVE: To test whether AVM angioarchitecture determines obliteration rate after radiosurgery. METHODS: This study was a retrospective analysis of 139 patients with AVM who underwent radiosurgery. Multiple angioarchitectural characteristics were reviewed on conventional angiogram on the day of radiosurgery: enlargement of feeding arteries, flow-related or intranidal aneurysms, perinidal angiogenesis, arteriovenous transit time, nidus type, venous ectasia, focal pouches, venous rerouting, and presence of a pseudophlebitic pattern. The radiation plan was reviewed for nidus volume and eloquence of AVM location. A chart review was performed to determine clinical presentation and previous treatment. Outcome was dichotomized into complete/incomplete obliteration, and various statistics were performed, examining whether outcome status was associated with the investigated factors. RESULTS: Marginal dose ranged from 15 to 25 Gy (mean, 18.8 Gy), with lower doses prescribed in eloquent locations. Sizes of AVMs ranged from 0.08 to 21 cm (mean, 3.78 ± 4.19 cm). Complete AVM obliteration was achieved in 92 patients (66%) and was related to these independent factors: noneloquent location (odds ratio [OR], 3.20), size (OR, 0.88), low flow (OR, 3.47), no or mild arterial enlargement (OR, 3.32), and absence of perinidal angiogenesis (OR, 2.61). Concerning the 3 last angioarchitectural characteristics, if no or only a single factor was present in an individual patient (n = 92 patients), obliteration was observed in 74 (80%); if 2 or 3 factors were present (n = 47), obliteration was observed in 18 patients (38%; OR, 6.62). CONCLUSION: Angioarchitectural factors that indicate high flow are associated with a lower rate of AVM obliteration after radiosurgery.

The use of 4D-CTA in the diagnostic work-up of brain arteriovenous malformations.

INTRODUCTION: We aimed to evaluate the use of time-resolved whole-head CT angiography (4D-CTA) in patients with an untreated arteriovenous malformation of the brain (bAVM), as demonstrated by catheter angiography (DSA). METHODS: Seventeen patients with a DSA-proven bAVM were enrolled. These were subjected to 4D-CTA imaging using a 320 detector row CT scanner. Using a standardized scoring sheet, all studies were analyzed by a panel of three readers. This panel was blind to the DSA results at the time of reading the 4D-CTA. RESULTS: 4D-CTA detected all bAVMs. With regard to the Spetzler-Martin grade, 4D-CTA disagreed with DSA in only one case, where deep venous drainage was missed. Further discrepancies between 4D-CTA and DSA analyses included underestimation of the nidus size in small lesions (four cases), misinterpretation of a feeding vessel (one case), misinterpretation of indirect feeding through pial collaterals (three cases) and oversight of mild arterial enlargement (two cases). 4D-CTA correctly distinguished low-flow from high-flow lesions and detected dural/transosseous feeding (one case), venous narrowing (one case) and venous pouches (nine cases). CONCLUSION: In this series, 4D-CTA was able to detect all bAVMs. Although some angioarchitectural details were missed or misinterpreted when compared to DSA, 4D-CTA evaluation was sufficiently accurate to diagnose the shunt and classify it. Moreover, 4D-CTA adds cross-sectional imaging and perfusion maps, helpful in treatment planning. 4D-CTA appears to be a valuable new adjunct in the non-invasive diagnostic work-up of bAVMs and their follow-up when managed conservatively.