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PubMed2004

Comparison of the radial forearm flap and the thinned anterolateral thigh cutaneous flap for reconstruction of tongue defects: an evaluation of donor-site morbidity.

The radial forearm flap is commonly used for reconstruction of tongue defects following tumor extirpation. This flap is easy to harvest and offers thin tissue with large-caliber vessels. However, its use leaves behind a conspicuous aesthetic deformity in the forearm and requires the sacrifice of a major artery of that limb, the radial artery. The anterolateral thigh cutaneous flap has found clinical applications in the reconstruction of soft-tissue defects requiring thin tissue. More recently, in a thinned form, the anterolateral thigh flap has been used for reconstructing defects of the tongue with functional results equivalent to that of the radial forearm flap. For the reconstruction of tongue defects, these two flaps could provide similar soft-tissue coverage, but they seem to result in different donor-site appearances. The donor site is closed primarily, leaving only a linear scar that is inconspicuous with normal clothing, and no functional deficit is left behind in the thigh. Thus, for the supply of flaps for tongue defects, a comparison between the radial forearm flap and the anterolateral thigh flap donor sites is provided in this study. Between December of 2000 and August of 2002, 41 patients who underwent reconstruction of defects of the tongue using either a radial forearm flap or an anterolateral thigh flap were evaluated. The focus was on the evaluation of the functional and aesthetic outcome of the donor site after harvesting these flaps for the purpose of reconstructing either total or partial tongue defects. Finally, a comparison was performed between the donor sites of the two flaps. The disadvantages of the radial forearm flap include the conspicuous unattractive scar in the forearm region, pain, numbness, and the sacrifice of a major artery of the limb. In some patients, the donor-site scar of the forearm acted as a social stigma, preventing these patients from leading a normal life. In contrast, the anterolateral thigh cutaneous flap, after thinning, achieved the same results in reconstructing defects of the tongue without the associated donor-site morbidity. Most importantly, the donor site in the thigh could be closed primarily in almost all patients without any functional deficit. The thinned anterolateral thigh cutaneous flap is a viable substitute for the radial forearm flap when reconstructing defects of the tongue. The results achieved are similar to those of the radial forearm flap, and the donor-site morbidity is significantly decreased.

Adult↗

PubMed2005

Selection of recipient vessels in double free-flap reconstruction of composite head and neck defects.

BACKGROUND: Massive defects of the head and neck regions after resection of advanced carcinoma often require two flaps for optimal reconstruction. This study focuses on the selection of proper recipient vessels. METHODS: A total of 262 free-flap transfers were performed in 130 patients using the two-flap approach (one patient received two flaps twice). RESULTS: For microvascular anastomosis of inner flaps (intraoral lining-bone reconstruction flaps), the ipsilateral facial artery was used in 56 flaps (42.8 percent), the ipsilateral superior thyroid artery was used in 49 flaps (37.4 percent), and a branch of the internal jugular vein was used as recipient vein in 101 flaps (77.1 percent). For external flaps (soft-tissue-external skin reconstruction flaps), the ipsilateral superior thyroid artery was used in 59 flaps (50.4 percent) and the transverse cervical artery was used in 19 flaps (16.2 percent). In 14 patients the inner flaps provided distal run-off for external flap revascularization. Only seven flaps required vein grafts; they were all used for external face reconstruction (2.8 percent). There were six total (2.3 percent) and 12 partial (4.6 percent) flap failures. CONCLUSIONS: Recipient vessel selection and preparation in primary head and neck cancer reconstruction requiring two simultaneous flaps should take into consideration (1) avoidance of unnecessary destruction during tumor ablations and preservation of as many neck vessels as possible, (2) length and diameter match between flap pedicles and recipient vessels to avoid vein grafts, and (3) possible need of another free-flap reconstruction for flap failure, complication, recurrence, or secondary primary cancers. The previously radiated or operated neck does not preclude the use of recipient vessels from that side. Distal run-off of the inner flap for external flap revascularization should be avoided if possible. Once those principles are observed, two-flap reconstruction for primary cancer presents no more difficulties than single-flap reconstruction.

Adult↗

PubMed2005

Strategies and options for free TRAM flap breast reconstruction in patients with midline abdominal scars.

BACKGROUND: Patients who have a midline abdominal scar from previous abdominal surgery often present a challenge when use of a transverse rectus abdominis myocutaneous (TRAM) flap is desired for breast reconstruction. In this study, the authors reviewed their experience with the TRAM flap for breast reconstruction in patients with midline abdominal scars to evaluate the various strategies used to optimize reconstructive outcomes. METHODS: Between January of 1994 and December of 2001, 43 patients with a midline abdominal scar underwent unilateral autologous tissue breast reconstruction with a TRAM flap at The University of Texas, M. D. Anderson Cancer Center. RESULTS: The mean age of the midline abdominal scar was 13 years (range, 4 to 45 years). In 26 patients, only free hemi-TRAM flaps were used for breast reconstruction. Free TRAM flaps were used in nine patients in whom zone II across the midline scar had an adequate blood supply and was able to be incorporated into the flap for breast reconstruction. In five patients, blood supplies from both sides of the TRAM flap were used to augment perfusion to the tissue across the midline scar. In three patients with infraumbilical midline scars, a free TRAM flap was designed higher in the abdomen so that the superior half of the flap was scar-free. CONCLUSIONS: Various strategies are available for autologous tissue breast reconstruction using a free TRAM flap in patients with a previous midline abdominal surgical scar. In some cases, the TRAM flap tissue across the midline scar can be used reliably for breast reconstruction.

Abdomen↗

PubMed2005

Unilateral postoperative chest wall radiotherapy in bilateral tissue expander/implant reconstruction patients: a prospective outcomes analysis.

BACKGROUND: Implant reconstruction has a major role to play in breast reconstruction, as some patients neither wish nor are suitable for autogenous reconstruction. The suitability of implant reconstruction in patients who may receive postoperative, adjuvant radiation therapy has not, however, been fully clarified. The purpose of this study was to evaluate complications, capsular contracture, aesthetic outcomes, and patient satisfaction in patients who have undergone bilateral tissue expander/implant reconstruction and unilateral, post exchange, adjuvant radiotherapy. In this study population, the effect of radiation can best be appreciated because the nonirradiated breast acts as a control. METHODS: A review of all bilateral tissue expander/implant reconstructions at a single cancer center was undertaken. Twelve patients who underwent bilateral expander/implant reconstruction and unilateral postexchange radiotherapy were eligible for participation. A prospective evaluation of complications, cosmesis, and patient satisfaction was performed. The evaluation of cosmesis and patient satisfaction was executed for 10 of the 12 patients, as two were dead at the time of follow-up. RESULTS: Mean follow-up was 23.5 months (range, 12 to 58.5 years). In 40 percent of patients, there was no discernible difference in capsular contracture between the irradiated and nonirradiated breasts. In 50 percent of patients, the irradiated breast demonstrated increased contracture by a single modified Baker grade. In 10 percent of patients, contracture of the irradiated breast was two modified Baker grades greater than that of the nonirradiated side (grade III versus grade I). CONCLUSION: For the majority of patients, the degree of capsular contracture was higher on the irradiated side, yet overall symmetry, aesthetic results, and patient satisfaction remained high. These data support the conclusion that immediate, bilateral breast reconstruction using tissue expansion and implants is an acceptable option for the subset of patients who may undergo unilateral, postexchange radiotherapy.

Algorithms↗

PubMed2006

Free flap reconstruction of foot and ankle defects in pediatric patients: long-term outcome in 91 cases.

BACKGROUND: Free tissue transfer has not been fully adopted as the primary mode of treating foot and ankle defects in potentially indicated patients, partly because of the lack of sizable vessels and the potential in the long term of differential growth in the flap and the recipient site. Also lacking are long-term outcome studies in these growing patients. METHODS: Between 1989 and 2002, 91 children with 93 foot and ankle defects underwent microsurgical reconstructions. The patients underwent reconstruction with flaps with a cutaneous component or with muscle flaps (skin-grafted). RESULTS: Fifty-eight defects were reconstructed with cutaneous/musculocutaneous flaps (37 fasciocutaneous and 21 musculocutaneous flaps), and 35 were reconstructed with skin-grafted muscle flaps. Thirteen patients underwent secondary free flap surgery, for a total of 106 flaps used to complete the reconstructions. Twelve cases underwent reexploration, and overall survival was 95.3 percent (101 of 106). Secondary deformities were present in 37.9 percent of skin/musculocutaneous flaps and 58.9 percent of skin-grafted muscle flaps (p = 0.029). More resurfacing procedures were performed in skin-grafted muscle flaps than in skin/musculocutaneous flaps (32.4 percent versus 12.1 percent; p = 0.0386). CONCLUSIONS: Free tissue transfer in pediatric patients is a viable and reliable option. Skin/musculocutaneous flaps and skin-grafted muscle flaps both had equal survival rates; however, flaps with a skin component required fewer secondary procedures to correct deformities. Whenever a skin component was present, it provided useful tissue during the secondary procedure and minimized complications. For plantar foot reconstructions, skin-grafted muscle flaps demonstrated a higher incidence of trophic ulcers and a higher need for resurfacing procedures than flaps with a skin component. Reconstructions of tendons in the immediate setting led to fewer secondary operations than staged tendon reconstructions.

Adolescent↗

PubMed2004

Mandibular reconstruction: are two flaps better than one?

This study compared the combined iliac and ulnar forearm flaps with the osteomusculocutaneous fibular free flap for mandibular reconstruction. A retrospective study of 40 patients who had oromandibular reconstruction was performed, of whom 23 patients had a combined iliac crest without skin and ulnar forearm free flap. Seventeen patients had an osteomusculocutaneous free fibular flap. Ten women and 30 men with a mean age of 57.5 years comprised this study population. Ninety percent of the cases were squamous cell carcinoma (55%, T4), of which 11% were recurrent tumors. Anterolateral mandibular defects constituted 52.9% of the fibular reconstructions and 60.9% accounted for the iliac/ulnar reconstructions. The mean bone gaps were 8.79 cm and 8.95 cm respectively. Functional evaluation was based on the University of Washington Questionnaire through phone calls and personal communication. The mean hospital stay was 15.43 days and 10.09 days for the fibular and iliac/ulnar flaps respectively. The facial artery (64.7%) and facial vein (60%) were the main recipient vessels for the fibular reconstructions whereas the external carotid artery (95.6%) and the internal jugular vein (66.7%) were the main recipient vessels for the iliac/ulnar reconstruction. Overall flap survival was 96.8% (100% of fibular flaps and 95.65% of iliac/ulnar flaps). Two flaps were lost in the iliac/ulnar series because of unsalvageable venous thrombosis. Local complications for the iliac/ulnar flaps were 30.4% but were 5.9% for the fibular reconstructions. Function such as speech, swallowing, and chewing were notably better in the fibular than the iliac/ulnar group in 23 of the patients tested. The cosmetic acceptance of 77.8% of the fibular flaps was judged to be excellent and good, whereas 71.4% of the iliac/ulnar flaps were rated good. It appears that within this study population the free osteomusculocutaneous fibular flap had fewer local complications and a higher flap survival rate than the combined iliac/ulnar forearm flaps. Overall functional outcome was also improved. The use of the double flap may be appropriate in massive oromandibular defects, but may be less appropriate in more modest functional reconstructions of mandibular defects.

Adult↗

PubMed2005

Nipple-areola reconstruction following chest-wall irradiation for breast cancer: is it safe?

Radiation therapy (RT) is considered by some to be a contraindication to nipple-areola reconstruction (NAR) particularly in patients with breast implant reconstruction. In this retrospective chart review, all patients who underwent breast reconstruction with tissue expanders and implants from 1997-2003 were reviewed. A subset of patients with a history of radiation therapy (pre- or postoperative) was identified. Postoperative complications, surgical technique, and the time course of reconstructive procedures were analyzed. Thirteen percent of patients with a history of RT had NAR compared with 36% of similarly reconstructed patients without a history of RT. Reconstruction was accomplished using a variety of local flaps, with an overall complication rate of 25%. Nipple-areola reconstruction after chest-wall irradiation in patients reconstructed with breast implants should be performed in carefully selected patients. Acceptable surgical candidates demonstrate resolution of acute radiation changes, no evidence of late radiation changes, and appropriate thickness of the mastectomy skin flaps.

Adult↗

PubMed2006

Nonexpansive immediate breast reconstruction using human acellular tissue matrix graft (AlloDerm).

Immediate breast reconstruction has become a standard of care following mastectomy for cancer, largely due to improved esthetic and psychologic outcomes achieved with this technique. However, the current historical standards--transverse rectus abdominis myocutaneous flap reconstruction and expander--implant surgery-still have limitations as regards patient morbidity, short-term body-image improvements, and even cost. To address these shortcomings, we employ a novel concept of human tissue replacement to enhance breast shape and provide total coverage, enabling immediate mound reconstruction without the need for breast expansion prior to permanent implant placement. AlloDerm (human acellular tissue matrix) is a human-derived graft tissue with extensive experience in various settings of skin and soft tissue replacement surgery. This report describes the success using acellular tissue matrix to provide total coverage over the prosthesis in immediate reconstruction, with limited muscle dissection. In this population, 49 patients (76 breasts) successfully underwent the acellular tissue matrix-based immediate reconstruction, resulting in durable breast reconstruction with good symmetry. These findings may predict that acellular tissue matrix-supplemented immediate breast reconstruction will become a new technique for the immediate reconstruction of the postmastectomy breast.

Biopsy↗

PubMed1998

Three-dimensional reconstruction of live embryos using robotic macroscope images.

To determine the three-dimensional (3-D) shape of a live embryo is a technically challenging task. We show that reconstructions of live embryos can be done by collecting images from different viewing angles using a robotic macroscope, establishing point correspondences between these views by block matching, and using a new 3-D reconstruction algorithm that accommodates camera positioning errors. The algorithm assumes that the images are orthographic projections of the object and that the camera scaling factors are known. Point positions and camera errors are found simultaneously. Reconstructions of test objects and embryos show that meaningful reconstructions are possible only when camera positioning and alignment errors are accommodated since these errors can be substantial. Reconstructions of early-stage axolotl embryos were made from sets of 33 images. In a typical reconstruction, 781 points, each visible in at least three different views, were used to form 1511 triangles to represent the embryo surface. The resulting reconstruction had a mean radius of error of 0.27 pixels (1.1 microns). Mathematical properties of the reconstruction algorithm are identified and discussed.

Algorithms↗

PubMed1997

Choice of initial conditions in the ML reconstruction of fan-beam transmission with truncated projection data.

We investigate the effects of initial conditions in the iterative maximum-likelihood (ML) reconstruction of fan-beam transmission projection data with truncation. In an iterative ML reconstruction, the estimate of the transmission reconstructed image in the previous iteration is multiplied by some factors to obtain the current estimate. Normally, a flat initial condition (FIC) or an image with equal positive pixel values is used as initial condition for an ML reconstruction. Usage of FIC has also been perceived as a way of preventing any bias on the reconstruction which may have come from the initial condition. When projection data have truncation, we show that using an FIC in an ML iterative reconstruction can introduce a bias to the reconstruction inside the densely sampled region (DSR), whose projection data have no truncation at any angle. To reduce this bias, we propose to use the largest right singular vector (LRSV) of the system matrix as the initial condition, and demonstrate that the bias can be reduced with the LRSV. When data truncation is reduced, the LRSV approaches the FIC. This result does not contradict to the use of FIC when projection data are not truncated. We also demonstrate that the reconstructed transmission image using LRSV as initial condition provides a more accurate attenuation coefficient distribution than that using FIC. However, the improvement is mostly in the area outside the DSR.

Humans↗

PubMed1998

Projection space image reconstruction using strip functions to calculate pixels more "natural" for modeling the geometric response of the SPECT collimator.

The spatially varying geometric response of the collimator-detector system in single photon emission computed tomography (SPECT) causes loss in resolution, shape distortions, reconstructed density nonuniformity, and quantitative inaccuracies. A projection space image reconstruction algorithm is used to correct these reconstruction artifacts. The projectors F use strip functions to calculate pixels more "natural" for modeling the two-dimensional (2-D) geometric response of the SPECT collimator transaxially to the axis of rotation. These projectors are defined by summing the intersection of an array of multiple strips rotated at equal angles to approximate the ideal system geometric response of the collimator. Two projection models were evaluated for modeling the system geometric response function. For one projector each strip is of equal weight, for the other projector a Gaussian weighting is used. Parallel beam and fan beam projections of a physical three-dimensional (3-D) Hoffman brain phantom and a Jaszczak cold rod phantom were used to evaluate the geometric response correction. Reconstructions were obtained by using the singular value decomposition (SVD) method and the iterative conjugate gradient algorithm to solve for q in the imaging equation FGq = p, where p is the projection measurement. The projector F included the new models for the geometric response, whereas, the backprojector G did not always model the geometric response in order to increase the computational speed. The final reconstruction was obtained by sampling the backprojection Gq at a discrete array of points. Reconstructions produced by the two proposed projectors showed improved resolution when compared against a unit-strip "natural" pixel model, the conventional image pixelized model with ray tracing to calculate the geometric response, and the filtered backprojection algorithm. When the reconstruction is displayed on fine grid points, the continuity and resolution of the image is preserved without the ring artifacts seen in the unit-strip "natural" pixel model. With present computing power, the geometric response correction using the proposed projection space reconstruction approach is not yet feasible for routine clinical use.

Algorithms↗

PubMed2005

Three-dimensional biplanar reconstruction of scoliotic rib cage using the estimation of a mixture of probabilistic prior models.

In this paper, we present an original method for the three-dimensional (3-D) reconstruction of the scoliotic rib cage from a planar and a conventional pair of calibrated radiographic images (postero-anterior with normal incidence and lateral). To this end, we first present a robust method for estimating the model parameters in a mixture of probabilistic principal component analyzers (PPCA). This method is based on the stochastic expectation maximization (SEM) algorithm. Parameters of this mixture model are used to constrain the 3-D biplanar reconstruction problem of scoliotic rib cage. More precisely, the proposed PPCA mixture model is exploited for dimensionality reduction and to obtain a set of probabilistic prior models associated with each detected class of pathological deformations observed on a representative training scoliotic rib cage population. By using an appropriate likelihood, for each considered class-conditional prior model, the proposed 3-D reconstruction is stated as an energy function minimization problem, which is solved with an exploration/selection algorithm. The optimal 3-D reconstruction then corresponds to the class of deformation and parameters leading to the minimal energy. This 3-D method of reconstruction has been successfully tested and validated on a database of 20 pairs of biplanar radiographic images of scoliotic patients, yielding very promising results. As an alternative to computed tomography-scan 3-D reconstruction this scheme has the advantage of low radiation for the patient, and may also be used for diagnosis and evaluation of deformity of a scoliotic rib cage. The proposed method remains sufficiently general to be applied to other reconstruction problems for which a database of objects to be reconstructed is available (with two or more radiographic views).

Algorithms↗

PubMed2005

Direct reconstruction of kinetic parameter images from dynamic PET data.

Our goal in this paper is the estimation of kinetic model parameters for each voxel corresponding to a dense three-dimensional (3-D) positron emission tomography (PET) image. Typically, the activity images are first reconstructed from PET sinogram frames at each measurement time, and then the kinetic parameters are estimated by fitting a model to the reconstructed time-activity response of each voxel. However, this "indirect" approach to kinetic parameter estimation tends to reduce signal-to-noise ratio (SNR) because of the requirement that the sinogram data be divided into individual time frames. In 1985, Carson and Lange proposed, but did not implement, a method based on the expectation-maximization (EM) algorithm for direct parametric reconstruction. The approach is "direct" because it estimates the optimal kinetic parameters directly from the sinogram data, without an intermediate reconstruction step. However, direct voxel-wise parametric reconstruction remained a challenge due to the unsolved complexities of inversion and spatial regularization. In this paper, we demonstrate and evaluate a new and efficient method for direct voxel-wise reconstruction of kinetic parameter images using all frames of the PET data. The direct parametric image reconstruction is formulated in a Bayesian framework, and uses the parametric iterative coordinate descent (PICD) algorithm to solve the resulting optimization problem. The PICD algorithm is computationally efficient and is implemented with spatial regularization in the domain of the physiologically relevant parameters. Our experimental simulations of a rat head imaged in a working small animal scanner indicate that direct parametric reconstruction can substantially reduce root-mean-squared error (RMSE) in the estimation of kinetic parameters, as compared to indirect methods, without appreciably increasing computation.

Algorithms↗

PubMed2006

Tomographic reconstruction using an adaptive tetrahedral mesh defined by a point cloud.

Medical images in nuclear medicine are commonly represented in three dimensions as a stack of two-dimensional images that are reconstructed from tomographic projections. Although natural and straightforward, this may not be an optimal visual representation for performing various diagnostic tasks. A method for three-dimensional (3-D) tomographic reconstruction is developed using a point cloud image representation. A point cloud is a set of points (nodes) in space, where each node of the point cloud is characterized by its position and intensity. The density of the nodes determines the local resolution allowing for the modeling of different parts of the image with different resolution. The reconstructed volume, which in general could be of any resolution, size, shape, and topology, is represented by a set of nonoverlapping tetrahedra defined by the nodes. The intensity at any point within the volume is defined by linearly interpolating inside a tetrahedron from the values at the four nodes that define the tetrahedron. This approach creates a continuous piecewise linear intensity over the reconstruction domain. The reconstruction provides a distinct multiresolution representation, which is designed to accurately and efficiently represent the 3-D image. The method is applicable to the acquisition of any tomographic geometry, such as parallel-, fan-, and cone-beam; and the reconstruction procedure can also model the physics of the image detection process. An efficient method for evaluating the system projection matrix is presented. The system matrix is used in an iterative algorithm to reconstruct both the intensity and location of the distribution of points in the point cloud. Examples of the reconstruction of projection data generated by computer simulations and projection data experimentally acquired using a Jaszczak cardiac torso phantom are presented. This work creates a framework for voxel-less multiresolution representation of images in nuclear medicine.

Algorithms↗

PubMed2005

Usefulness of ultrasonic strain measurement-based shear modulus reconstruction for diagnosis and thermal treatment.

We previously reported an ultrasonic strain measurement-based one-dimensional (1-D) shear modulus reconstruction technique using a regularization method for differential diagnosis of malignancies on human superficial tissues (e.g., breast tissues). Here, ultrasonic strain measurement-based 2-D and 3-D shear modulus reconstruction techniques are described, and the 1-D technique is reviewed and subsequently applied to various human in vivo tissues, including deeply situated tissues (e.g., liver). Because soft tissues are deformed in 3-D space by externally situated arbitrary mechanical sources, the accuracy of the low-dimensional (i.e., 1-D or 2-D) reconstructions is lower to that of 3-D reconstruction due to occurrence of erroneous reconstruction artifacts (i.e., the reconstructed modulus is different than reality). These artifacts are confirmed on simulated inhomogeneous cubic phantoms containing a spherical homogenous inclusion using numerically calculated deformation data. The superiority of quasi-real-time imaging of the shear modulus is then demonstrated by comparing it with conventional B-mode imaging and strain imaging from the standpoints of monitoring the effectiveness of minimally invasive thermal therapy as well as differential diagnosis. Because the 2-D and 3-D techniques require special ultrasonic (US) equipment, the 1-D technique using conventional US imaging equipment is used, even though erroneous artifacts will occur. Specifically, the 1-D technique is applied as a diagnostic tool for differentiating malignancies in human in vivo liver and breast tissue, and a monitoring technique for determining the effectiveness of interstitial electromagnetic wave (micro and rf) thermal therapy on human in vivo liver and calf in vitro liver. Even when using the 1-D technique, reconstructed shear moduli were confirmed to be a suitable measure for monitoring thermal treatment as well as differential diagnosis. These results are encouraging in that they will promote use of 2-D and 3-D reconstruction techniques.

Algorithms↗

PubMed2004

Trilobed skin flap on the face: for reconstruction of full-thickness or commissural defects.

BACKGROUND: Although many local skin flaps have been described for reconstruction of defects on the face, there are still some difficulties in reconstruction of full-thickness defects of alar and ear region and commissural defects in periorbital and perioral region. OBJECTIVE: A trilobed skin flap can offer single-stage reconstruction of difficult full-thickness or commissural defects. We performed trilobed skin flaps in reconstruction of the defects on the face. The design of the flap and outcomes of the procedures are presented. METHODS: Twelve patients with skin cancer on the face were operated under general or local anesthesia. After tumor resection, defects were closed with a trilobed skin flap. Patients were followed-up for a minimum 6 months. RESULTS: There was no early or late complication in all patients. Oral competence was achieved in reconstruction of the oral commissure. A new lateral canthus with angles as in the original one was created. Alar and ear reconstructions were performed at one session using the same flap without a graft. The outcome was satisfactory. CONCLUSION: Because it is easy to obtain a trilobed skin flap, it can be used for reconstruction of canthal, oral, and commissural defects, and the new canthus, mouth, and commissures with angles as in the original ones can be created. In addition, the flap can be used for reconstruction of full-thickness defects in the alar region and the ear.

Aged↗

PubMed2006

Use of reconstructed computed tomography for the assessment of joint spaces in the canine elbow.

OBJECTIVES: To assess the accuracy of reconstructed computed tomography for imaging canine elbow joint spaces. METHODS: Computed tomography scans of eight cadaveric elbows were obtained and reconstructed computed tomography images were formatted in the dorsal and sagittal planes. Humeroradial and humeroulnar joint space measurements were obtained from these images. Intra-observer and inter-observer variations in joint space measurements were assessed, as was the effect of specimen positioning (inter-image variation). After freezing, four elbows were sectioned in the dorsal plane and four in the sagittal plane. In addition to visual comparison of the frozen sections with reconstructed computed tomography images, joint space measurements were obtained from frozen sections and compared with those from reconstructed computed tomography images. Variation was assessed using statistical calculations and graphical techniques. RESULTS: Both inter-image and intra-observer analyses revealed good agreement and low variation between data sets. Inter-observer correlation was only moderate, though variation was low. Visually, the reconstructed computed tomography images accurately reflected the frozen section anatomy. Agreement between frozen section and reconstructed computed tomography joint space measurements was good, with minimal variation. CLINICAL SIGNIFICANCE: These results indicate that reconstructed computed tomography is capable of accurately imaging elbow joint spaces and precise joint space measurements can be obtained. Reconstructed computed tomography may be useful for determining joint space measurements and detecting elbow incongruencies in dogs with elbow dysplasia.

Animals↗

PubMed2000

Feasibility of brain volumetric analysis and reconstruction of images by transfontanel three-dimensional ultrasound.

Based on the authors' experience with reconstruction of the heart using three-dimensional echocardiography, the authors assessed the feasibility of three-dimensional reconstruction of brain images using transfontanelle ultrasound in selected cases of infants with abnormal intracranial findings. A conventional 5-MHz ultrasound transducer inside a transducer holder was rotated 180 degrees around its vertical axis using a computer-controlled stepper motor to acquire multiple sequential cross-sections of the brain. The raw digital data of this three-dimensionally recorded dataset were transferred to a PC-based workstation for further analysis. The reconstruction of the three-dimensional brain images and volumetric analysis were undertaken using a new dedicated software capable of three-dimensional reconstruction and volumetric analysis (Echo-PAC-3D, version 1.2 Beta, GE Vingmed, Horton, Norway). The reconstruction of sequential slices from the stored three-dimensional data allowed the visualization of the epicortical extension and volumetric measurements of the focal ischemic infarction in the superior tempoparietal lobe in a 2-week-old newborn with a focal ischemic brain lesion. In other 2-week-old newborns, the extension and volume of a periventricular hemorrhage was visualized by three-dimensional reconstruction of coronal cross-sectional images from the acquired three-dimensional dataset. The three-dimensional reconstruction of the lateral ventricles allowed the three-dimensional visualization and estimation of ventricular dilatation in milliliters in an 8-week-old infant with hydrocephalus. Three-dimensional reconstruction of brain images and volume estimation of brain lesions and cavities by ultrasound may provide new insights into the morphology and extension of ultrasonographically visible brain lesions.

Brain↗