Automatic quantification of multi-modal rigid registration accuracy using feature detectors.

In radiotherapy, the use of multi-modal images can improve tumor and target volume delineation. Images acquired at different times by different modalities need to be aligned into a single coordinate system by 3D/3D registration. State of the art methods for validation of registration are visual inspection by experts and fiducial-based evaluation. Visual inspection is a qualitative, subjective measure, while fiducial markers sometimes suffer from limited clinical acceptance. In this paper we present an automatic, non-invasive method for assessing the quality of intensity-based multi-modal rigid registration using feature detectors. After registration, interest points are identified on both image data sets using either speeded-up robust features or Harris feature detectors. The quality of the registration is defined by the mean Euclidean distance between matching interest point pairs. The method was evaluated on three multi-modal datasets: an ex vivo porcine skull (CT, CBCT, MR), seven in vivo brain cases (CT, MR) and 25 in vivo lung cases (CT, CBCT). Both a qualitative (visual inspection by radiation oncologist) and a quantitative (mean target registration error-mTRE-based on selected markers) method were employed. In the porcine skull dataset, the manual and Harris detectors give comparable results but both overestimated the gold standard mTRE based on fiducial markers. For instance, for CT-MR-T1 registration, the mTREman (based on manually annotated landmarks) was 2.2 mm whereas mTREHarris (based on landmarks found by the Harris detector) was 4.1 mm, and mTRESURF (based on landmarks found by the SURF detector) was 8 mm. In lung cases, the difference between mTREman and mTREHarris was less than 1 mm, while the difference between mTREman and mTRESURF was up to 3 mm. The Harris detector performed better than the SURF detector with a resulting estimated registration error close to the gold standard. Therefore the Harris detector was shown to be the more suitable method to automatically quantify the geometric accuracy of multimodal rigid registration.

Clinical, diagnostic and therapeutic features of keratocystic odontogenic tumors: a review.

Keratocystic odontogenic tumors (KCOTs) are benign but locally aggressive lesions of the gnathic skeleton with high propensity to recur following surgical treatment. High proliferative activity of KCOTs epithelial cells is considered as one of the factors contributing to their aggressive clinical behavior. Aggressive growth within the jaws, tendency to invade surrounding anatomical structures and occasional malignant alteration are the features that distinguish KCOTs from other types of odontogenic tumors. Due to their unique clinical and biological features, KCOTs still present an important problem in oral and maxillofacial surgery. This is especially true when a choice of the most appropriate treatment modality should be made. Establishing balance between effective reduction of recurrence risk and selection of a less aggressive surgical procedure is an issue that should be carefully considered for each individual patient.

[Pathophysiological mechanism of the developing radicular cyst of the jaw].

The radicular cysts are result of inflammatory process in the periapical tissues associated with necrotic and infected pulps. Humoral and cellular immune responses play a central role in the pathogenesis of these lesions. The most important role in the growth of these lesion have proinflammatore cytokine TNF-alpha, IL-1 and IL-6. Cytokine can be secreted by macrophages, monocytes and other cells of the immune system and can participate in skeletal homeostasis including osteoclastic formation, and bone resorption in maxillofacial region. The aim of this study is to give a consise rewiew for mechanism of growth of maxilofacial radicular cysts, indicated of clinical aspect, as well as expalined role of cytokine in this pathophysiology process.

The concentration of TNF-alpha correlate with number of inflammatory cells and degree of vascularization in radicular cysts.

OBJECTIVE: To correlate values of tumor necrosis factor-alpha (TNF-alpha) depending on the count of inflammatory cells with degree of vascularization in cystic fluid of radicular cysts. MATERIAL AND METHODS: We investigated TNF-alpha concentration in 43 radicular cysts obtained from patients undergoing surgery, under local anaesthesia, and after aspiration of cystic fluid from non-ruptured cysts by enzyme-linked immunosorbent assay assay in respect of different clinical parameters as well as by histomorphometric analyses. RESULTS: Significantly higher concentration of TNF-alpha is associated with smaller radicular cysts, higher protein concentration in cystic fluid as well as with higher presence of inflammatory cells, and increased degree of vascularization in pericystic tissues and cyst wall thickness. CONCLUSIONS: We believe that determination of TNF-alpha in cystic fluid simultaneously with other parameters can be an additional parameter for clinical diagnosis of inflammed cysts.

[Comparison of single and double doses of hydrochlorothiazide in the treatment of arterial hypertension with special emphasis on changes in vascular reactivity]. / Usporedba jednokratne i dvokratne doze hidroklorotiazida u lijecenju arterijske hipertenzije s posebnim osvrtom na promjenu zilne reaktivnosti.

The hypotensive effects of 100 and 50 mg hydrochlorothiazide (HTZ) were evaluated in 30 mild-to-moderate hypertensives, divided into two groups, with diastolic pressure between 95 and 110 mmHg. In both groups, the average MAP reduction was 15% (P less than 0.05). There were no significant differences in antihypertensive effects between single (50 or 100 mg o.d.) and double (25 or 50 mg b.i.d.) doses of the same drug. Blood pressure control was better after two than after one month on each of the various dosing schedules. Side-effects were mild and well tolerated: observed was a significant increase in triglyceride level from 3.0 +/- 1.8 to 4.8 +/- 2.4 mmol/L under the treatment with 100 mg HTZ o.d. and a statistically significant decrease in potassium level from 4.4 +/- 0.3 mmol/L to 4.1 +/- 0.3 mmol/L after two months treatment with 50 mg HTZ o.d. Unexpectedly, these changes were not dose-related. The venous reflexes showed atenuated response to norepinephrine after HTZ treatment, while arterial inflow, venous capacity and venous outflow increased significantly (P less than 0.05). It is concluded that HTZ exhibits some direct vasodilator activity and that the pharmacokinetic features of this drug do not correlate with the pharmacodynamic ones. At least in the management of mild-to-moderate arterial hypertension single daily dosage is quite adequate.

Indapamide versus beta-blocker therapy: a double-blind, crossover study in essential hypertension.

A controlled, double-blind, double-placebo, crossover clinical trial was carried out in 24 mild to moderate hypertensives of either sex to compare the anti-hypertensive and other effects of indapamide (2.5 mg) and pindolol (15 mg). After a 2-week run-in placebo period the patients were randomly assigned to one of the drugs in the study for 6 weeks. After a second 2-week placebo period, the subjects received the alternative drug for an additional 6 weeks. Both drugs produced a significant and similar decrease in arterial blood pressure (averaging 19 mmHg for systolic and 15 mmHg for diastolic blood pressure; p less than 0.05), with minimal differences between the drugs in this respect (p greater than 0.10). Pulse, rate, however, was significantly reduced (from 76 to 67 beats/min; p less than 0.05) only with pindolol. The laboratory data did not change appreciably, and few side-effects were reported. It is concluded that indapamide and pindolol at the dosage levels used are drugs of comparable antihypertensive activity.