Evaluation of Cone-Beam Computed Tomography Scans to Develop a Staging Method of External Carotid Artery Calcification.

Background: The objective of this study was to develop a practical staging method for reporting external carotid artery calcifications (ECACs) using cone-beam computed tomography (CBCT) imaging, specifically to standardize reporting for oral and maxillofacial radiologists. Methods: This retrospective study evaluated 489 CBCT scans for the presence of ECACs. Two calibrated evaluators assessed the scans in all three orthogonal planes, using the axial plane to develop the staging system. Calcifications were graded on a scale from 0 to 5. Results: ECACs were found in 170 out of 489 scans (34.7%). There was a statistically significant increase in ECAC distribution with age progression. The prevalence of ECACs was similar between genders. Grade 1 calcifications were most common in the 51-60 age group, Grade 2 in the 61-70 and 71-80 groups, and Grades 3 and 4 in the 81-90 group. No Grade 5 calcifications were observed in any age group. The inter-rater reliability showed an excellent correlation in the identification and grading of ECACs. Conclusions: The proposed grading system enables oral and maxillofacial radiologists to quantitatively report ECACs, facilitating timely referrals to physicians for further evaluation and early intervention, thereby potentially reducing the risk of cardiovascular events.

Effective doses of dental cone beam computed tomography: effect of 360-degree versus 180-degree rotation angles.

OBJECTIVES: The aims of this study were to compare radiation absorbed dose (AD) and effective dose (ED) to tissues from cone beam computed tomography (CBCT) scans with 360-degree versus 180-degree rotations with use of different fields of view (FOV), to compare EDs calculated from measured ADs versus dose area product (DAP) values, and to compare doses to the lens of the eye (LOE) from different scan parameters. STUDY DESIGN: ADs for each protocol were measured in tissues, including the LOE, by using an anthropometric phantom. EDs were calculated on the basis of dosimetry (EDm) and DAP values (EDd). Dose differences were determined with analysis of variance (ANOVA). RESULTS: ADs and EDs were substantially lower for 180-degree rotation scans compared with 360-degree rotation scans (P < .01). Remainder tissues had the greatest effect on effective dose for most FOVs. Doses were generally lower with small FOVs compared with large FOVs. Most EDm values were lower than EDd values in large FOVs but higher in small FOVs. Differences in EDm and EDd were variable and unpredictable. LOE doses were smaller with the 180-degree scans and smaller FOVs. CONCLUSIONS: Radiation doses were generally lower with 180-degree rotation scans and smaller FOVs. These parameters should be used for CBCT acquisitions, whenever possible, and should be made available in all units.

Cardiac remodeling in Drosophila arises from changes in actin gene expression and from a contribution of lymph gland-like cells to the heart musculature.

Understanding the basis of normal heart remodeling can provide insight into the plasticity of the cardiac state, and into the potential for treating diseased tissue. In Drosophila, the adult heart arises during metamorphosis from a series of events, that include the remodeling of an existing cardiac tube, the elaboration of new inflow tracts, and the addition of a layer of longitudinal muscle fibers. We have identified genes active in all these three processes, and studied their expression in order to characterize in greater detail normal cardiac remodeling. Using a Transglutaminase-lacZ transgenic line, that is expressed in the inflow tracts of the larval and adult heart, we confirm the existence of five inflow tracts in the adult structure. In addition, expression of the Actin87E actin gene is initiated in the remodeling cardiac tube, but not in the longitudinal fibers, and we have identified an Act87E promoter fragment that recapitulates this switch in expression. We also establish that the longitudinal fibers are multinucleated, characterizing these cells as specialized skeletal muscles. Furthermore, we have defined the origin of the longitudinal fibers, as a subset of lymph gland cells associated with the larval dorsal vessel. These studies underline the myriad contributors to the formation of the adult Drosophila heart, and provide new molecular insights into the development of this complex organ.

The Hox gene abdominal-A specifies heart cell fate in the Drosophila dorsal vessel.

The Drosophila melanogaster dorsal vessel is a linear organ that pumps blood through the body. Blood enters the dorsal vessel in a posterior chamber termed the heart, and is pumped in an anterior direction through a region of the dorsal vessel termed the aorta. Although the genes that specify dorsal vessel cell fate are well understood, there is still much to be learned concerning how cell fate in this linear tube is determined in an anteroposterior manner, either in Drosophila or in any other animal. We demonstrate that the formation of a morphologically and molecularly distinct heart depends crucially upon the homeotic segmentation gene abdominal-A (abd-A). abd-A expression in the dorsal vessel was detected only in the heart, and overexpression of abd-A induced heart fate in the aorta in a cell-autonomous manner. Mutation of abd-A resulted in a loss of heart-specific markers. We also demonstrate that abd-A and sevenup co-expression in cardial cells defined the location of ostia, or inflow tracts. Other genes of the Bithorax Complex do not appear to participate in heart specification, although high level expression of Ultrabithorax is capable of inducing a partial heart fate in the aorta. These findings for the first time demonstrate a specific involvement for Hox genes in patterning the muscular circulatory system, and suggest a mechanism of broad relevance for animal heart patterning.