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PubMed2004

An evaluation of impression techniques for multiple internal connection implant prostheses.

STATEMENT OF PROBLEM: Movement of impression copings inside the impression material using an open-tray impression technique during clinical and laboratory phases may cause inaccuracy in transferring the 3-dimensional spatial orientation of implants intraorally to the definitive cast. Consequently the restoration may require corrective procedures. PURPOSE: This in vitro study evaluated the accuracy of 3 different impression techniques using polyether impression material to obtain a precise definitive cast for a multi-unit implant restoration with multiple internal connection implants. MATERIAL AND METHODS: A reference acrylic resin model with 4 internal connection implants (3i Implant Innovations) was fabricated. Forty-five medium-consistency polyether impressions (Impregum Penta) of this model were made with square impression copings using an open-tray technique. Three groups of 15 specimens each were made with different impression techniques: in the first group, nonmodified square impression copings were used (NM group); in the second group, square impression copings were used and joined together with autopolymerizing acrylic resin before the impression procedure (R [resin] group); and in the third group, square impression copings previously airborne-particle abraded and coated with the manufacturer-recommended impression adhesive were used (M [modified] group). Matching implant replicas were screwed into the square impression copings in the impressions. Impressions were poured with ADA type IV stone (New Fujirock). A single calibrated examiner blinded to the nature of the impression technique used examined all definitive casts to evaluate the positional accuracy (mum) of the implant replica heads using a profile projector (at original magnification x10). These measurements were compared to the measurements calculated on the reference resin model which served as control. Data were analyzed with a 1-way analysis of variance at alpha=.05, followed by the Student Newman-Keuls test (alpha=.05). RESULTS: The data obtained with the profile projector revealed significant differences within the 3 impression techniques ( P <.001). The Student Newman-Keuls procedure disclosed significant differences between the groups, with group R casts being significantly more accurate than group NM and group M casts ( P =.05). The mean distance (+/-SD) between the posterior implants compared to the reference acrylic resin model was 18.17 mum (+/- 6.4) greater for group R casts, 41.27 mum (+/- 8.4) greater for group M casts, and 46.21 mum (+/- 8.9) greater for group NM casts. Distances between the anterior implants were also greater than those recorded on the reference model. The distance was 15.23 mum (+/- 5.9) greater on group R casts, 38.17 mum (+/- 8.3) greater on group M casts, and 43.23 mum (+/- 8.7) greater on group NM casts. CONCLUSION: Within the limitations of this study, improved accuracy of the definitive cast was achieved when the square impression copings joined together with autopolymerizing acrylic resin were used to make an impression of multiple internal connection implants.

Acrylic Resins↗

PubMed2005

Bioavailability of 2,3',4,4',5-pentachlorobiphenyl (PCB118) and 2,2',5,5'-tetrachlorobiphenyl (PCB52) from soils using a rat model and a physiologically based extraction test.

The bioavailability of coplanar 2,3',4,4',5-pentachlorobiphenyl (PCB118) and nonplanar 2,2',5,5'-tetrachlorobiphenyl (PCB52) from soils representing a range in organic carbon (OC), clay content and pH were investigated using an in vivo rat model and an in vitro physiologically based extraction test (PBET) to assess the role of soil and chemical properties on bioavailabilty. Affinity to soil and persistence of PCBs have been shown to increase with increasing soil organic carbon (OC) content, PCB chlorination, and PCB coplanarity. In the in vivo tests for both PCB118 and PCB52, the AUCs following iv injection were significantly higher than the AUCs for all soil groups, indicating that the soil matrix can reduce the absolute bioavailability of PCB118 and PCB52. However, no significant differences were detected between soils of different properties. In the in vitro PBET, significant differences in the mobilization of PCB118 and PCB52 were observed among soils, and PCBs had the least mobilization from the soil with the highest OC content consistent with hydrophobic partitioning theory. Also, significantly less PCB118 was mobilized relative to PCB52 in the PBET assay, showing the potential impact of spatial orientation and chlorine content on bioavailability. No correlation between the in vitro PBET and the in vivo rat model was observed for the PCBs. Although the in vitro PBET and related assays may serve as an indicator of bioavailability, it is likely to underestimate what can be released from a soil in an in vivo assay.

Aluminum Silicates↗

PubMed2004

Three-dimensional ultrasound in margin evaluation for breast tumor excision using Mammotome.

Sonographic evidence of tumor removal by Mammotome excision does not confirm histological clearance. The operator finds it hard to determine if a malignant tumor has been fully removed, leaving a safe margin in the direction of each border; that is, the spatial orientation during tumor retrieval is not well-established by naked eye under sonographic guidance. We propose a computational imaging process to extract reasonable tumor contour in pre- and postoperative data sets for sonographic guidance so that Mammotome excision can help the operator to evaluate the surgical outcome. There were five tumors in the study, including three benign and two malignant. The lesion of interest was delineated after 2-D examination was completed, then it was analyzed with 3-D breast ultrasound (US). To give a reference point for correlations between pre- and postoperative images, we used a marker tape pasted on the skin within the transducer scanning area and then the preoperative 3-D US images were obtained. Subsequently, 2-D breast US was applied during Mammotome operation. After the Mammotome procedures were finished, the postoperative 3-D US images were obtained; thus, we gained two different data sets of 3-D US images that were used for later analysis for evaluating the extension of postoperative margin status. From the results, the safe margin was not satisfactory in all directions, because the minimum differences measured by the proposed algorithm were not large enough in all five cases, and this was proved from two malignant mastectomy specimens. The experimental results representing this inadequate Mammotome excision can be visualized through the computer aid. The comparison of tumor contour and excision margin may possibly be used for small malignant tumors in the future to improve the breast-conserving surgery.

Breast Neoplasms↗

PubMed2004

Intracranial collateral pathways assessed by contrast-enhanced three-dimensional transcranial color-coded sonography.

Individual parameter settings of the duplex machine and limited insonation angles may influence the visualization of small intracranial vessels in 2-D transcranial color-coded sonography. The aim of our study was the morphologic assessment of intracranial collateral pathways (first auditory area celiac artery, A(1)CA; anterior communicating artery, AComA; first parental generation celiac artery P(1)CA; posterior communicating artery, PComA) using 3-D transcranial color-coded duplex sonography (3-D TCCS) and digital subtraction angiography (DSA). A total of 41 patients with large vessel disease and 30 patients who had suffered subarachnoidal hemorrhage (mean age 52 +/- 15 years) were involved. In all patients, angiography was performed within 10 days following 3-D sonography. The patients were investigated with a color-coded duplex system using the power mode. Contrast enhancement was achieved by continuous infusion of a galactose-based echo-enhancer using a perfusor pump. The 3-D system consists of an electromagnet that induces a low-intensity magnetic field near the head of the patient. A magnetic position sensor is attached to the ultrasound (US) probe and transmits the spatial orientation to a personal computer, which also receives the corresponding 2-D images from the video port of the duplex machine. Angiography revealed a "complete" circle of Willis in one third of the patients and, in the remaining patients at least one vessel was hypoplastic or absent. Sufficient temporal bone windows allowed the sonographic investigation of 466 (94%) of 497 expected arterial segments. The comparison of both techniques resulted in a weighted kappa value of 0.56 for the A(1)CA and 0.63 for the AComA. In the posterior circulation kappa values of 0.56 for the P(1)CA and 0.43 for the PComA were calculated. In 50 vessels (10%), 3-D sonography misdiagnosed the diameter of a collateral vessel as normal and angiography revealed hypoplasia or aplasia of this vessel. The main advantage of 3-D TCCS is that it enables the investigator to reconstruct virtually any arbitrary view angle. Compared with angiography or magnetic resonance (MR) angiography, 3-D sonography can be performed easily in critically ill patients on stroke units or intensive care units. The noninvasive assessment of the circle of Willis may be useful in patients who undergo carotid surgery without angiography. Combined with hemodynamic information, contrast-enhanced 3-D TCCS might increase the diagnostic impact of transcranial US.

Angiography, Digital Subtraction↗

PubMed2006

Utility of imaging mass spectrometry (IMS) by matrix-assisted laser desorption ionization (MALDI) on an ion trap mass spectrometer in the analysis of drugs and metabolites in biological tissues.

INTRODUCTION: The properties and potential liabilities of drug candidate are investigated in detailed ADME assays and in toxicity studies, where findings are placed in context of exposure to dosed drug and metabolites. The complex nature of biological samples may necessitate work-up procedures prior to high performance liquid chromatography-mass spectrometric (HPLC-MS) analysis of endogenous or xenobiotic compounds. This concept can readily be applied to biological fluids such as blood or urine, but in localized samples such as organs and tissues potentially important spatial, thus anatomical, information is lost during sample preparation as the result of homogenization and extraction procedures. However, the localization of test article or spatial identification of metabolites may be critical to the understanding of the mechanism of target-organ toxicity and its relevance to clinical safety. METHODS: Tissue imaging mass spectrometry (IMS) by matrix-assisted laser desorption ionization (MALDI) and ion trap mass spectrometry (MS) with higher order mass spectrometric scanning functions was utilized for localization of dosed drug or metabolite in tissue. Laser capture microscopy (LCM) was used to obtain related samples from tissue for analyses by standard MALDI-MS and HPLC-MS. RESULTS: In a toxicology study, rats were administered with a high dosage of a prodrug for 2 weeks. Birefringent microcrystalline material (10-25 microm) was observed in histopathologic formalin-fixed tissue samples. Direct analysis by IMS provided the identity of material in the microcrystals as circulating active drug while maintaining spatial orientation. Complementary data from visual cross-polarized light microscopy as well as standard MALDI-MS and HPLC-MS experiments on LCM samples validated the qualitative results obtained by IMS. Furthermore, the HPLC-MS analysis on the LCM samples afforded a semi-quantitative assessment of the crystalline material in the tissue samples. DISCUSSION: IMS by MALDI ion trap MS proved sensitive, specific, and highly amenable to the image analysis of traditional small molecule drug candidates directly in tissue.

Animals↗

PubMed2003

Attentional modulation of threshold sensitivity to first-order motion and second-order motion patterns.

Previous studies [e.g. Vision Research 40 (2000) 173] have shown that when observers are required to selectively attend to one of two, spatially-adjacent patches containing either first-order (luminance-defined) or second-order (contrast-defined) motion, threshold sensitivity for identifying the direction of second-order motion, but not first-order motion, is enhanced for the attended stimuli. The processing of second-order motion, unlike first-order motion, may, therefore, require attention. However, other studies have found little evidence for differential effects of attention on the processing of first-order and second-order motion [Investigative Ophthalmology and Visual Science 42(4) (2001) 5061]. We investigated the effects of attention instructions on the ability of observers to identify the directions and spatial orientations of luminance-defined and contrast-defined motion stimuli. Pairs of motion stimuli were presented simultaneously and threshold performance was measured over a wide range of drift temporal frequencies and stimulus durations. We found: (1) direction discrimination thresholds for attended motion stimuli were lower than those for unattended stimuli for both types of motion. The magnitude of this effect was reduced when the observers were not given prior knowledge of which patch of motion (attended or unattended) they had to judge first. (2) Direction discrimination for first-order motion was similarly affected at all temporal frequencies and durations examined, but for second-order motion the effects of attention depended critically on the drift temporal frequency and stimulus duration used. (3) Orientation discrimination showed little or no influence of attention instructions. Thus, whether or not attention influences the processing of second-order motion depends crucially on the precise stimulus parameters tested. Furthermore under appropriate conditions the processing of first-order motion is also influenced by attention, albeit to a lesser extent than second-order motion.

Attention↗

PubMed2001

[Alterations of the basal membrane in middle ear cholesteatoma].

Cholesteatoma epithelium is characterized by a keratinocyte disregulation accompanied by destruction of the ossicles and other bony parts of the temporal bone. Immunohistochemical methods using antibodies to fibronectin, tenascin and metalloproteinases were used to assess the alterations of the instrinsic and extrinsic components of the basement membrane. Spatial orientation of the basement membrane was preserved in histological sections. Collagen type IV, tenascin, fibronectin, basic fibroblastic growth factor (bFGF), and matrix metalloproteinases (MMPs) are related to the matrix, perimatrix of normal or pathological tissues. They were studied immunohistologically in twenty cholesteatomas, eight samples of normal auditory canal skin, and six specimens of normal middle ear mucosa. Cholesteatomas displayed alterations of the basal membrane, with presence of MMPs and a linear immunoreactivity for collagen type IV and laminin, disrupted in areas with intense inflammation. The electronic microscope revealed protrusions, duplications, thickening and disruptions of the lamina densa of the basement membrane. Thus, we conclude, that MMPs and bFGF could play an important role maintaining the proliferative activity and the aggressive behaviour of cholesteatoma in the middle ear.

Basilar Membrane↗

PubMed1984

Clinical applications of a new type of real-time two-dimensional Doppler flow imaging system.

The clinical significance of a newly developed real-time 2-dimensional (2-D) Doppler flow imaging technique was assessed. In the instrumentation of the echocardiograph, the pulsed Doppler mechanism was incorporated in a wide-angle, phased-array system. The Doppler flow signals obtained from the cardiac chamber were processed on the basis of the autocorrelation principle. The direction, velocity and variance of the intracardiac blood flow were calculated in real time and displayed in the color-coded mode on the television screen, and were superimposed on the 2-D echocardiographic image of the heart. The technique was used in 20 healthy subjects and 100 cardiac patients. The new technique clearly visualized the whole aspect of intracardiac blood flow by the cine mode in real time; thus, the technique may be called Doppler cineangiocardiography. The mitral inflow and the aortic ejection flow were clearly demonstrated. A regurgitant jet from the valve orifices was dynamically visualized as seen in the cineangiogram. The spatial orientation and extent of the regurgitant jet were easily assessed. The jet stream through the stenotic mitral orifice was well imaged in the left ventricular cavity, showing a variety of stream directions. Intracardiac shunts in ventricular septal defect and atrial septal defect were clearly visualized. The defect could be localized on the interventricular septum on the basis of the site where the shunt flow spurted, although the echocardiographic interruption was not demonstrated in the 2-D echocardiographic image of the cardiac structure. Although some technical problems remain, our new technique greatly improves the diagnostic efficacy of ultrasound.

Adolescent↗

PubMed1999

Usefulness of three-dimensional transesophageal echocardiographic imaging for evaluating narrowing in the coronary arteries.

Coronary artery (CA) imaging has relied on invasive techniques for diagnosing stenotic lesions. Two-dimensional techniques are limited in obtaining optimal longitudinal views of all segments of the CA because of their spatial orientations. Three-dimensional echocardiography (3DE) may produce any desired cross-sectional views and reconstruct 3-dimensional images from a volumetric data set. Its role in CA imaging has not been fully explored. The aim of this study was to evaluate the potential of 3DE in visualizing CAs and in assessing the severity of stenosis. We performed transesophageal 3DE in 46 patients. Images were collected sequentially with the transducer rotated through 180 degrees. From the 3DE data sets of all 46 patients, cross-sectional views and 3-dimensional images of CAs were reconstructed. For segment-by-segment comparison between CA angiography and 3DE in semiquantitative analysis of coronary stenosis, 5 segments were defined for the proximal CA tree in 20 patients who underwent both procedures. The left main, anterior descending, circumflex, and right CAs were visualized from 3DE in 100%, 100%, 98%, and 72%. The available lengths of these segments from 3DE were 12+/-4 mm (range 4 to 22), 15+/-6 mm (range 6 to 36), 30+/-12 mm (range 13 to 60), and 18+/-9 mm (range 6 to 36), respectively. Comparison between 3DE and CA angiography in semiquantitative estimation of CA stenosis resulted in complete agreement in 83% of the segments (kappa value = 0.7). The sensitivity and specificity of 3DE in detecting significant stenosis (> or =50%) were 84% and 97%. In conclusion, transesophageal 3DE allows imaging of the proximal CA, detection of stenotic lesions, and estimation of the severity of stenosis.

Coronary Angiography↗

PubMed2000

Complications and recommended practices for electrosurgery in laparoscopy.

BACKGROUND: Electrosurgery is one of the most commonly used energy systems in laparoscopic surgery. Two major categories of potential complications related to electrosurgery in laparoscopy are mechanical trauma and electrothermal injury. The latter can result from unrecognized energy transfer in the operational field or, less commonly, to unnoticed stray current outside the laparoscopic field of view. Stray current can result from insulation failure, direct coupling, or capacitive coupling. METHODS: We reviewed the literature concerning essential biophysics of electrosurgery, including electrosurgical waveform differentiation, tissue effect, and variables that determine tissue effect. The incidence of electrosurgical injuries and possible mechanisms responsible for the injuries are discussed. Different types of injuries may result in different clinical manifestations and histopathological findings. Gross and microscopic pathological check-ups of the injury sites may distinguish between different mechanisms, and thus provide further clues postoperatively. RESULTS: Several recommended practices are proposed to avoid electrosurgical injury laparoscopically. To achieve electrosurgical safety and to prevent electrosurgical injuries, the surgical team should have a good understanding of the biophysics of electrosurgery, the basis of equipment and general tissue effects, as well as the surgeon's spatial orientation and hand-eye coordination. Some intraoperative adjuvant procedures and newly developed safety devices have become available may aid to improve electrosurgical safety. CONCLUSIONS: Knowledge of the biophysics of electrosurgery and the mechanisms of electrosurgical injury is important in recognizing potential complications of electrosurgery in laparoscopy. Procedures for prevention, intraoperative adjuvant maneuvers, early recognition of the injury with in-time salvage treatment, and alertness to postoperative warning signs can help reduce such complications.

Burns, Electric↗

PubMed1976

Late clinical problems with Beall model 103 and 104 mitral valve prostheses: hemolysis and valve wear.

The purpose of this study was to determine the influence on hemolysis of the spatial orientation of the struts in the Beall mitral valve prosthesis, Models 103 and 104. Thirteen pairs of patients were selected to match struts oriented parallel and perpendicular to the left ventricular outflow tract axis. The average time after operation was 3.73 years. Complete blood counts and relative serum chemistry values were determined.

Adult↗

PubMed2003

A peptide mimetic of an anti-CD4 monoclonal antibody by rational design.

The development of rational methods to design 'continuous' sequence mimetics of discontinuous regions of protein sequence has, to now, been only marginally successful. This has been largely due to the difficulty of constraining the recognition elements of a mimetic structure to the relative conformational and spatial orientations present in the parent molecule. Using peptide mapping to determine 'active' antigen recognition residues, molecular modeling, and a molecular dynamics trajectory analysis, we have developed a peptide mimic of an anti-CD4 antibody, containing antigen contact residues from multiple CDRs. The design described is a 27-residue peptide formed by juxtaposition of residues from 5 CDR regions. It displays an affinity for the antigen (CD4) of 0.9nM, compared to 2nM for the parent antibody ST40. Nevertheless, the mimetic shows low biological activity in an anti-retroviral assay.

Amino Acid Sequence↗

PubMed2002

Models of eukaryotic gradient sensing: application to chemotaxis of amoebae and neutrophils.

Eukaryotic cells can detect shallow gradients of chemoattractants with exquisite precision and respond quickly to changes in the gradient steepness and direction. Here, we describe a set of models explaining both adaptation to uniform increases in chemoattractant and persistent signaling in response to gradients. We demonstrate that one of these models can be mapped directly onto the biochemical signal-transduction pathways underlying gradient sensing in amoebae and neutrophils. According to this scheme, a locally acting activator (PI3-kinase) and a globally acting inactivator (PTEN or a similar phosphatase) are coordinately controlled by the G-protein activation. This signaling system adapts perfectly to spatially homogeneous changes in the chemoattractant. In chemoattractant gradients, an imbalance between the action of the activator and the inactivator results in a spatially oriented persistent signaling, amplified by a substrate supply-based positive feedback acting through small G-proteins. The amplification is activated only in a continuous presence of the external signal gradient, thus providing the mechanism for sensitivity to gradient alterations. Finally, based on this mapping, we make predictions concerning the dynamics of signaling. We propose that the underlying principles of perfect adaptation and substrate supply-based positive feedback will be found in the sensory systems of other chemotactic cell types.

Amoeba↗

PubMed1993

Cross-bridge attachment and stiffness during isotonic shortening of intact single muscle fibers.

Equatorial x-ray diffraction pattern intensities (I10 and I11), fiber stiffness and sarcomere length were measured in single, intact muscle fibers under isometric conditions and during constant velocity (ramp) shortening. At the velocity of unloaded shortening (Vmax) the I10 change accompanying activation was reduced to 50.8% of its isometric value, I11 reduced to 60.7%. If the roughly linear relation between numbers of attached bridges and equatorial signals in the isometric state also applies during shortening, this would predict 51-61% attachment. Stiffness (measured using 4 kHz sinusoidal length oscillations), another putative measure of bridge attachment, was 30% of its isometric value at Vmax. When small step length changes were applied to the preparation (such as used for construction of T1 curves), no equatorial intensity changes could be detected with our present time resolution (5 ms). Therefore, unlike the isometric situation, stiffness and equatorial signals obtained during ramp shortening are not in agreement. This may be a result of a changed crossbridge spatial orientation during shortening, a different average stiffness per attached crossbridge, or a higher proportion of single headed crossbridges during shortening.

Actins↗

PubMed2003

Serotonin 5-HT1A receptors might control the output of cortical glutamatergic neurons in rat cingulate cortex.

The present study was designed to investigate the distribution of serotonin 5-HT1A receptor protein (5-HT1A-immunoreactivity) and its localization within cortical pyramidal neurons of the rat cingulate cortex. This experimental direction was inspired by recent data showing the role of 5-HT1A receptors in the pathology of schizophrenia, and in the mechanism of action of novel antipsychotic drugs as well as by the importance of the cingulate cortex in regulation of cognitive functions. It was found that 5-HT1A-immunoreactivity was densely distributed in neuronal eyelash-like elements, and their size, shape and spatial orientation may suggest concentration of 5-HT1A-immunopositive material in the proximal fragments of axons of cortical neurons. Moreover, it was observed that these 5-HT1A-immunopositive fragments were present predominately on proximal fragments of axons of pyramidal neurons, which was evidenced by double labeling experiments using glutamate and non-phosphorylated neurofilament H as markers of the cortical pyramidal cells. The 5-HT1A receptor immunoreactivity was localized distally to the inhibitory GABAergic terminals of chandelier and basket cells surrounding the pyramidal cell bodies and occasionally surrounding short initial segment of axonal hillock of pyramidal neurons. These anatomical data indicate that 5-HT1A receptors might control the excitability and propagation of information transmitted by the pyramidal cells. Moreover, our results indicate that drugs operating via 5-HT1A receptors in the cingulate cortex might control from this level the release of glutamate in the subcortical structures. Finally, the 5-HT1A receptors present in the cingulate cortex, as demonstrated in the present study, may constitute an important target for drugs used to repair dysfunction of glutamate neurotransmission, which is observed for example in schizophrenia.

Animals↗

PubMed2006

Visual field expansion in patients with retinitis pigmentosa.

BACKGROUND: To determine the effectiveness of using spectacle-mounted prisms for field expansion in patients with retinitis pigmentosa (RP). METHODS: Vision-related activities of daily living (V-ADL) questionnaire scores and functional visual field score (FFS) measurements were conducted before and after a one-month trial of spectacle-mounted prisms in those patients with RP who had residual central visual fields of less than 10 degrees. RESULTS: 16 patients were recruited who met study inclusion criteria. Mean V-ADL and FFS at baseline were 67.6 (73%) and 22.9 (46%), respectively. After a 1-month trial using spectacle-mounted prisms, V-ADL and FFS demonstrated significant improvement to 73.4 (80%, p < 0.05) and 27.0 (54%, p < 0.001), respectively. INTERPRETATION: Spectacle-mounted prisms effectively create visual field expansion and noticeable spatial orientation benefits in patients with RP. This may provide an adjunctive tool in low vision rehabilitation and should be considered in all cases with RP with less than 10 degrees of visual field.

Adult↗

PubMed1999

Fluorescent probes used to monitor membrane interfacial polarity.

The polarity of the interface between a lipid bilayer membrane and bulk water is an important physical parameter of the membrane. It is likely that several membrane-dependent biological functions are modulated by this property. However, interfacial polarity can be difficult to define because of an imprecise knowledge of the molecular nature of the interface. Nevertheless, attempts have been made to measure this quantity with the use of fluorescent probes which are sensitive to the solvent polarity. Often, however, other factors, such as the rate of solvent relaxation must be known in order to interpret the fluorescent properties in terms of the dielectric constant. In addition, the spatial orientation and location of the fluorophore are often not known precisely. Nevertheless, there have been successful efforts to gain a more accurate knowledge of this aspect of membrane physical properties and its relationship to biological phenomena is discussed.

Cell Membrane↗

PubMed1998

Multiplanar reformatting and three-dimensional reconstruction: for pre-operative assessment of the thoracic aorta by computed tomography.

INTRODUCTION: Conventional CT demonstrates pathology of the thoracic aorta. This study aimed to evaluate the additional contributions to surgical planning of multiplanar reformatting, maximum intensity projections and three-dimensional (3-D) reconstruction. DESIGN: Retrospective. SUBJECT AND METHODOLOGY: Fifty-three patients with newly diagnosed pathology of the thoracic aorta were scanned over a 15-month period; 25 scans were spiral acquisitions. Scans were acquired during and following rapid injection of 100 ml of intravenous iopromide. The reconstructed data was displayed as axial images, oblique or other multiplanar reformats and shaded surface display 3-D reconstructions. Two radiologists and two surgeons reviewed the images. The axial images were assessed initially, subsequently the reformats and 3-D reconstructed views were examined looking particularly for additional information that might add to the surgical management. RESULTS: Pathologies encountered were aortic dissection (21 patients, including two with Marfan's syndrome), saccular aneurysms (eight), fusiform aneurysms (16), aortic root and ascending aortic dilatation (seven) and coarctation (one). The relationship of aneurysms and dissections to major vessels are better shown with 3-D reconstruction or oblique reformats. Morphology of saccular aneurysms, particularly the neck, is well shown with 3-D reconstruction. Coarctation was best demonstrated by oblique reformats. There was little additional information from 3-D reconstruction or reformats in assessment of type A dissection. Improved spatial orientation by visualization in varying projections was helpful for surgical planning in certain cases of type B dissection, fusiform aneurysms and aortic root and ascending aortic root dilatation. Spiral acquisitions have the advantage of speed and hence a greater anatomical coverage for a single breath-hold. CONCLUSION: Oblique reformats and 3-D reconstruction, although using identical data as the axial images, in specific cases were felt to aid surgical assessment of aneurysms and dissections, thus assisting pre-operative planning.

Aortic Dissection↗