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At least 649 records · Page 36Linked to original sources

PubMed2003

Immediate breast reconstruction using biodimensional anatomical permanent expander implants: a prospective analysis of outcome and patient satisfaction.

Immediate breast reconstruction is offered to the majority of women requiring a mastectomy for cancer treatment. Improvements in implant technology have seen the evolution of shaped, fixed-volume implants and permanent expanders. The theoretical benefits of biodimensional anatomical expander implants include better reconstructed breast form, the potential for achieving this at a single procedure, and the avoidance of a contralateral procedure as a result of improved ipsilateral cosmesis. The aim of the present study was to assess outcome after immediate breast reconstruction using the McGhan 150 permanent expander implant. A total of 107 consecutive patients (129 breast reconstructions) were studied over a 30-month period; 49 patients (68 reconstructions) had submuscular implant placement alone, and 58 patients (61 reconstructions) had an implant in conjunction with a latissimus dorsi flap. The mean patient age was 47 years (range, 22 to 72 years) and the mean follow-up was 18 months (range, 6 to 40 months). Outcome was assessed in the following four ways: geometric measurements, evaluation of photographs by four independent observers, linear numerical analogue scale, and a quality-of-life questionnaire. Geometric measurements after surgery showed median differences that were highly consistent with good symmetry. Transverse breast width difference between breasts was 0.35 cm, vertical breast height difference was 0.8 cm, sternal notch-to-nipple distance difference was 0.6 cm, midclavicular line-to-nipple distance difference was 0.5 cm, nipple-to-inframammary crease distance difference was 0.5 cm, midline-to-nipple distance difference was 0 cm, and projection difference was 0 cm. Photographic assessment by four observers who evaluated shape, cleavage, symmetry, and overall outcome produced correlation values of 0.73 to 0.81. More than 75 percent of each of these parameters was scored as good or excellent. A numerical analogue scale (from 1 to 10) assessing overall result by the surgeon and patient revealed good (7 to 8) or excellent (9 to 10) scores in 83 and 82 percent of respondents, respectively. Quality-of-life data showed that 81 and 88 percent of women felt "a little" or "not at all" less feminine, respectively, and 88 percent were satisfied with the appearance of their breasts. A total of 88 percent of women would also choose the same reconstructive procedure if faced with the same cancer diagnosis. Complication rates were low; infections occurred in 6.2 percent of reconstructions, hematoma occurred in 1.6 percent, and implant loss occurred in 3.9 percent. Only 24 of 107 patients (22 percent) elected to have a synchronous contralateral breast adjustment, and four of 107 (4 percent) chose to have a subsequent procedure for symmetry. Biodimensional expander implants used in immediate breast reconstruction are associated with high levels of patient and surgeon satisfaction. Optimum breast form can be achieved during a single operation with a low incidence of complications.

Adult↗

PubMed2003

Modified technique for nipple-areolar reconstruction: a case series.

SUMMARY: Thousands of women undergo postmastectomy breast reconstruction each year. Part of the reconstruction of an aesthetically pleasing breast is a high-quality nipple-areolar reconstruction. The goals for this reconstruction include appropriate nipple projection, areolar color, and areolar texture. Presented in this article is a novel technique that achieves these goals without the need for harvesting a distant skin graft. The nipple-areolar reconstruction is performed under local anesthesia. A skate flap is designed to achieve the nipple reconstruction. The skate flap donor sites are closed primarily, and the outline of the areola is then defined with a round template. The skin is then incised at the border of the areola, and a full-thickness graft is elevated to the base of the reconstructed nipple. After hemostasis is achieved, the skin graft is placed back down in its original position and a bolster dressing is applied. Tattooing is performed 4 months postoperatively to achieve a color match. Twenty-four consecutive patients underwent 31 nipple-areolar reconstructions using this novel technique. All patients achieved excellent results without complications. One patient did experience a partial skate flap loss; however, the wound healed secondarily without the need for revision. The technique described herein can achieve the goals of nipple-areolar reconstruction, including appropriate nipple projection, areolar color, and areolar texture, without the need for a distant skin graft.

Adult↗

PubMed2004

Nasal reconstruction--beyond aesthetic subunits: a 15-year review of 1334 cases.

A retrospective analysis was performed on 1334 patients who underwent nasal reconstruction between 1986 and 2001. The senior author performed all reconstructions in this series after Mohs' histographic excisions. Only secondary reconstructions were performed without a preceding Mohs' excision. Methods of reconstruction, number of operations per patient, locations of defects, and complications were recorded. Using preoperative and postoperative photographs, aesthetic results were reviewed. Basal cell carcinoma was the most common lesion, followed by squamous cancer and melanoma. The average age of the patients was 51 years. Cancers most commonly arose on the dorsum, ala, and tip. Of 1334 cases, a 1.9 percent recurrence rate was documented. The average time between surgery and clinical recognition of recurrence was 39 months. All recurrent lesions were reexcised by the Mohs' technique. Eighty-one percent of reconstructions were completed in three or fewer stages. Seventy-five percent of reconstructions were completed in two stages. Primary dermabrasion or primary laserbrasion using carbon dioxide or erbium lasers was used in nearly every case. Early secondary dermabrasion or laserbrasion was used in a few cases where indicated. A 1.2 percent revision rate was noted (16 patients). Thirteen partial flap necroses required revision. Three patients experienced dehiscence at the donor site of paramedian forehead flaps. A preferred philosophy toward nasal reconstruction is described. The goal is to achieve optimal cosmetic and functional results while minimizing stages and resection of healthy tissue. Six core principles are advocated that guide efficient and successful nasal reconstruction: (1) maximal conservation of native tissue is advised; (2) reconstruction of the defect, not the subunit, is advised; (3) complementary ablative procedures, such as primary dermabrasion, enhance the final result and decrease the number of revisionary procedures; (4) primary defatting also decreases the number of revisionary procedures; (5) when possible, the use of axial pattern flaps is preferred; and (6) good contour is the aesthetic endpoint.

Adult↗

PubMed2005

Patterns of care for immediate and early delayed breast reconstruction following mastectomy.

BACKGROUND: The purpose of this study was to analyze factors associated with immediate or early (up to 4 months) postmastectomy reconstruction and to update and extend knowledge of patterns of care for reconstruction, using data from a large, population-based surveillance program. METHODS: Procedures included analysis of data for 27,703 women diagnosed with breast carcinoma who underwent mastectomy in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program between 1998 and 2000. Descriptive, univariate, and multivariate logistic regression analyses were used to estimate the odds of selecting immediate or early reconstruction while simultaneously considering independent variables. RESULTS: Results of multivariate analyses showed that, for those women who underwent reconstruction, the proportion of black women was approximately one-third less than that of white women (odds ratio, 0.64; 95 percent CI, 0.55 to 0.74). Women who chose reconstruction were between two and four times more likely [odds ratio range, 2.27 (95 percent CI, 2.04 to 2.52) to 3.56 (95 percent CI, 2.53 to 4.58)] to be younger compared with those women aged 65 years and older, and were nearly 75 percent more likely to be diagnosed at the in situ stage compared with those diagnosed at later stages. Women choosing reconstruction were significantly less likely to live in Iowa and Seattle/Puget Sound and more likely to live in Detroit and Atlanta compared with women in San Francisco/Oakland, Connecticut, Hawaii, New Mexico, and Utah, and were significantly less likely to have never married or be widowed compared with married women. Women undergoing reconstruction were more than twice as likely to have had mastectomy with removal of the uninvolved contralateral breast. CONCLUSIONS: Results of this study updated previous research and showed that immediate or early reconstruction is used by a small but increasing proportion of women diagnosed with breast carcinoma who undergo mastectomy. Previous knowledge was extended by showing that use of reconstruction is most strongly associated with patient age and removal of the uninvolved contralateral breast and, to a lesser magnitude (but still significantly), with race, stage, marital status, and geographic location.

Adult↗

PubMed2006

Satisfaction with prophylactic mastectomy and breast reconstruction in genetically predisposed women.

BACKGROUND: Prophylactic mastectomy with breast reconstruction is a risk-reducing strategy for women at increased risk of breast cancer. It remains a very radical intervention, and long-term data on satisfaction are insufficiently available. In the present follow-up study, the authors assess satisfaction with prophylactic mastectomy and breast reconstruction and its impact on sexual relationships. METHODS: The authors conducted a retrospective study using a short self-report questionnaire administered to 114 genetically predisposed women who underwent prophylactic mastectomy and breast reconstruction mainly by subpectorally implanted silicone prostheses performed at one institution. RESULTS: The median follow-up time between prophylactic mastectomy/breast reconstruction and completion of the questionnaire was 3 years. Sixty percent of all participants were satisfied with the result of prophylactic mastectomy/breast reconstruction. Satisfaction was significantly and negatively correlated with perceived lack of information, experienced complications, ongoing complaints, whether or not the reconstructed breasts feel "like your own," and not choosing this type of breast reconstruction again. Adverse effects in the patient's sexual relationship were strongly correlated with perceived lack of information, discrepant expectations, ongoing complaints and limitations, whether or not the reconstructed breasts feel "like your own," altered feelings of femininity, partner's negative perception on femininity and sexuality, and not choosing this type of breast reconstruction again. CONCLUSIONS: A majority of women would choose the procedure again, but adverse effects and untoward changes in the perception of the sexual relationship need to be addressed in the counselling of women at high risk, to optimize an informed choice and enable adequate adjustment postoperatively.

Activities of Daily Living↗

PubMed2006

A two-year prospective analysis of trunk function in TRAM breast reconstructions.

BACKGROUND: Functional outcomes in breast reconstruction are important quality measures and aid in patients' decision-making process. To address the concerns of abdominal wall morbidity with transverse rectus abdominis musculocutaneous (TRAM) flap reconstructions, the authors prospectively evaluated the long-term effects of postmastectomy breast reconstruction on trunk function using objective clinical measures. METHODS: Using a multicenter prospective cohort design, they recruited women undergoing first-time immediate or delayed breast reconstructions from 12 centers and 23 plastic surgeons. Trunk functional data, objectively measured with Cybex machines, for patients with an expander/implant, pedicle TRAM, and free TRAM reconstructions were evaluated preoperatively and at postoperative years 1 and 2 in 183 patients. The effects of procedure type, timing, and laterality on trunk peak torque and range of motion were analyzed using linear regression. RESULTS: At 2 years postoperatively, procedure type, timing, and laterality did not significantly affect the range of motion for trunk flexion and extension. Peak torque for trunk flexion at year 2 was significantly decreased in patients with TRAM compared with expander/implant reconstructions (p < 0.05), with a 6 to 19 percent decrease in flexion peak torque. However, no significant difference in flexion peak torque was found between patients with free and pedicle TRAM reconstructions. CONCLUSIONS: The authors found that (1) breast cancer patients with TRAM reconstructions had a less than 20 percent long-term deficit in trunk flexion peak torque and (2) there was no significant difference in trunk function between patients receiving pedicle and free TRAM reconstructions.

Biomechanical Phenomena↗

PubMed2006

A single surgeon's 12-year experience with tissue expander/implant breast reconstruction: part I. A prospective analysis of early complications.

BACKGROUND: Multiple prior reports are conflicted regarding the true incidence of complications following implant-based breast reconstruction. A review of a single surgeon's extensive experience with tissue expander/implant reconstruction provides the opportunity to critically evaluate outcomes in a uniformly treated patient population. The objective of this study was to analyze the development of early complications in patients following two-stage implant breast reconstruction. METHODS: A review of all tissue expander/implant reconstructions performed by a single surgeon over the 12-year period from July of 1992 to June of 2004 was performed. A prospectively maintained database was analyzed with respect to reconstructive and early complication data on 1522 reconstructions in 1221 patients. Early complications were defined as those occurring 12 months or less from initiation of reconstruction. RESULTS: The overall rate of early complications was 5.8 percent; the rate of premature expander removal was 2.7 percent. The most common complication was infection (2.5 percent). The incidence of complications after tissue expander insertion (8.5 percent) was significantly higher than that after the exchange procedure (2.7 percent). The rate of complications was significantly higher in patients with a history of preoperative chest wall irradiation. There was no difference in the incidence of complications in patients who were expanded during chemotherapy and those who were not. CONCLUSIONS: Tissue expander/implant reconstruction is a safe, reliable method of reconstruction with minimal early complications. Early complications are more common after expander insertion. Chemotherapy administered during tissue expansion does not increase the rate of complications. The rate of complications, although higher in previously irradiated patients, remains low.

Breast Implantation↗

PubMed2005

The importance of end-systole for optimal reconstruction protocol of coronary angiography with 16-slice multidetector computed tomography.

OBJECTIVES: Multidetector-row computed tomography coronary images are usually analyzed in mid-diastole (MD). Because of slow coronary motion also in end-systole (ES), we evaluated the impact on image quality of including ES images and defined an efficient reconstruction protocol. MATERIAL AND METHODS: In 50 coronary multidetector-row computed tomography studies, 9 reconstructions (at 10% increments of the RR interval) were graded for image quality. Multiple combinations of reconstructions were compared. RESULTS: MD (60-70% of the RR interval) offered the best image quality. In 44% patients, the best reconstruction for >or=1 coronary was found in ES (20-30%). Their heart rate was higher (68.2+/-9.9 bpm vs. 59.2+/-8.8 bpm, P=0.0014). Combining ES and MD consistently offered superior image quality and less nonevaluable vessels than even larger numbers of diastolic reconstructions alone. A combination of 2-3 reconstructions was most efficient. Adding more reconstructions did not significantly improve results. CONCLUSIONS: Combining ES and MD reconstructions reduces nonevaluable coronary arteries, particularly with higher heart rates. A protocol including 2-3 reconstructions is the most efficient.

Adolescent↗

PubMed2004

Factors determining shape and symmetry in immediate breast reconstruction.

Although a number of studies compare different techniques of breast reconstruction there seems to be a paucity of information documenting the factors that affect breast shape and symmetry after immediate reconstruction. A photographic analysis by 5 plastic surgeons (who were blinded to the nature of the procedure) of 62 patients undergoing skin-sparing mastectomy and immediate reconstruction was undertaken in an endeavor to identify these factors. Autologous techniques used included deepithelialized pedicled transverse rectus abdominis musculocutaneous (TRAM) flaps (n = 23; in 9 patients a bilateral breast reduction using inverted-T keyhole skin markings was performed, and the TRAM flap was used to fill the reduced skin pocket) and 4 patients had extended latissimus dorsi flaps. Prosthetic reconstruction was undertaken in 35 patients in whom a bilateral breast reduction skin pattern was used in 23 (prosthesis inserted submuscularly in 5 patients and subcutaneously in 18 patients) or, in another 12 patients the skin envelope was retained and the prosthesis was inserted partially submuscularly in 7 patients and subcutaneously in 5 patients. As a total group, the results of autologous reconstruction were better than prosthetic reconstruction (P = 0.048, Mann-Whitney U test). However, when a breast reduction pattern was used and the prosthesis was inserted subcutaneously, the results were not significantly better than when the reduced skin envelope was filled by autologous tissue (P = 0.64, Mann-Whitney U test). Failure to replace the areola leads to a smaller reconstructed breast and asymmetry. The skin envelope, when retained in toto, seems to be a major factor affecting breast shape. In patients with a reduction pattern applied, the skin envelope again seems to be a major factor affecting shape, because the results are similar whether the envelope was filled with autologous tissue or prosthetic material. The neoparenchyma is an important factor affecting breast projection. In patients undergoing prosthetic reconstruction, the results were significantly better with subglandular placement compared with submuscular placement (P = 0.007, Mann-Whitney U test). Patients who developed a complication (requiring debridement in the operating room or that took more than a month to achieve healing) had a poorer cosmetic result (P = 0.015, Mann-Whitney U test). These factors need to be considered when planning breast reconstruction to optimize the aesthetic result.

Adult↗

PubMed2005

The suspension technique to avoid the use of tissue expanders in breast reconstruction.

BACKGROUND: Immediate or delayed breast reconstruction is usually performed using expansion techniques or pedicled or free flaps. The suspension technique hereby described can reduce the number of surgical stages, as well as donor-site sequelae. TECHNIQUE: The authors describe a new technique of breast reconstruction with implants using a nonabsorbable mesh to create a superior abdominal cutaneous flap, which contributes to the skin envelope of the reconstructed breast. The advantage of this technique is the opportunity to use immediately a definitive prosthesis also in cases requiring a mastectomy with the resection of a large amount of skin, consequently reducing the indications of tissue expanders or myocutaneous flaps. RESULTS: We performed the "suspension technique" in 67 cases of immediate reconstruction and in 6 cases of delayed reconstruction. No further surgery under general anesthesia was necessary in 56 patients (76.7%). In 14 cases (19.2%), a second operation under general anesthesia was necessary for implant replacement, capsula revision, and nipple and areola (NAC) reconstruction. In 3 cases (4.1%), implant removal was necessary due to implant exposition or infection. In 33 patients, only NAC reconstruction was performed under local anesthesia. In our series, capsula contracture was graded as Baker I in 24 cases, grade II in 16 cases, grade III in 9 cases, and grade IV in 1 case. Breast symmetry, patient's satisfaction, and surgeon cosmetic evaluation were respectively scored 7.56, 7.75, and 7.60 (range from 1 to 10). CONCLUSION: In conclusion, this technique can be applied in cases requiring a large skin resection at the time of mastectomy and refusing a reconstruction with myocutaneous flaps or a second surgery, necessary if a reconstruction with tissue expanders is planned.

Adult↗

PubMed2005

Use of fascia component of the anterolateral thigh flap for different reconstructive purposes.

The anterolateral thigh flap is commonly used for reconstruction of soft-tissue defects located at various sites of the body. This versatile flap offers many advantages to the reconstructive microsurgeons for the treatment of difficult defects. From 2000 to 2005, 70 anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. We retrospectively reviewed these patients and found that the fascia lata component of the flap was used for different purposes in 19 patients. The fascia lata component of the flap was used for suspension of the flap in lip reconstruction in 12 patients, for reconstruction of dural defect in the scalp in 2 patients, for reconstruction of tendon defects in the forearm in 3 patients, and for reconstruction of fascia defect in the abdominal wall in the remaining 2. Complete loss of the flap was seen in an anterolateral thigh flap (5.2%) that was used for lower lip reconstruction. One flap necrosed partially (5.2%), and it was treated with surgical debridement and transposition of latissimus dorsi musculocutaneous flap. The objective of this study is to focus on the reliability of the fascial component of the anterolateral thigh flap. Although many authors have described other advantages of the anterolateral thigh flap extensively, this peculiarity has not been stressed adequately. Anterolateral thigh flap offers a thick and vascular fascial component with large amounts that can be used for different reconstructive purposes, and it should be taken into consideration as an important advantage of the flap, together with other well-known advantages.

Adolescent↗

PubMed2006

Immediate reconstruction of oncologic hemipelvectomy defects.

BACKGROUND: Soft tissue and bony tumors of the pelvis are rare, but when they occur, treatment presents both an oncologic surgical and a reconstructive challenge. After reconstruction, soft tissue defects can be large and there is usually exposed bone and/or joint. A retroperitoneal abdominal wall defect may also be present. Flap mobilization is generally necessary to eliminate dead space and cover the exposed bone, viscera, and/or prosthetic orthopedic material. We performed immediate reconstruction on 11 patients after radical pelvic resections for tumor. PATIENTS AND METHODS: Eleven cases of radical pelvic resection and immediate reconstruction were identified during the period from 1992 to 2002 at University Hospital, Newark, New Jersey. All patients were treated by both the orthopedic oncology and plastic surgery teams. A retrospective review of office charts and hospital records was performed. Data were gathered regarding the following: tumor type and oncologic history, extent of resection, reconstructive modality, complications, and outcome. RESULTS: All patients underwent radical resection of pelvic masses depending on the tumor type and location. Tumor types included chondrosarcoma (6), Paget osteosarcoma (1), giant cell tumor (1), metastatic uterine carcinoma (2), and invasive squamous cell carcinoma arising in a chronic decubitus ulcer (1). The reconstructive procedures performed were the following: rectus abdominus flaps (6), gluteus maximus musculocutaneous flaps (3), and thigh fillet flaps (2). The retroperitoneal defects were repaired with primary tissue approximation of the surrounding available musculature. Additionally, Gore-Tex mesh was used in 2 cases, tensor fascia lata was used in 2 cases, and acellular dermal matrix in 1 case. Blood loss for the combined procedures ranged from 400 mL to 1400 mL. The follow-up period in this series ranged from 24 to 114 months. Complications included skin flap loss with subsequent infection (1), local cellulitis controlled with antibiotics (1), regional recurrence (2). The postoperative course was uneventful for the remainder of the cases. CONCLUSION: Soft tissue reconstructions after extensive pelvic resections always present as complex reconstructive problems. Reconstruction is dictated by the size of the defects and by tissue availability. The extent and type of resections vary according to tumor size and location. In our experience, local pedicled muscle-based flaps, if available, usually provide adequate tissue mass to eliminate dead space, cover the extent of the wound, and close the retroperitoneal defect. Microvascular tissue transfer is always an option but was reserved in our series for cases with no suitable local alternative.

Adolescent↗

PubMed2007

Dynamic function of the ACL-reconstructed knee during running.

Little is known about the three-dimensional behavior of the anterior cruciate ligament (ACL) reconstructed knee during dynamic, functional loading, or how dynamic knee function changes over time in the reconstructed knee. We hypothesized dynamic, in vivo function of the ACL-reconstructed knee is different from the contralateral, uninjured knee and changes over time. We measured knee kinematics for 16 subjects during downhill running 5 and 12 months after ACL reconstruction (bone-patellar tendon-bone or quadrupled hamstring tendon with interference screw fixation) using a 250 frame per second stereoradiographic system. We used repeated-measures ANOVA to ascertain whether there were differences between the uninjured and reconstructed limbs and over time. We found no differences in anterior tibial translation between limbs, but reconstructed knees were more externally rotated and in more adduction (varus) during the stance phase of running. Anterior tibial translation increased from 5 to 12 months after surgery in the reconstructed knees. Anterior cruciate ligament reconstruction failed to restore normal rotational knee kinematics during dynamic, functional loading and some degradation of graft function occurred over time. These abnormal motions may contribute to long-term joint degeneration associated with ACL injury and reconstruction.

Adult↗

PubMed1998

Optimal CT scanning plan for long-bone 3-D reconstruction.

Digital computed tomographic (CT) data are widely used in three-dimensional (3-D) reconstruction of bone geometry and density features for 3-D) modeling purposes. During in vivo CT data acquisition the number of scans must be limited in order to protect patients from the risks related to X-ray absorption. Aim of this work is to automatically define, given a finite number of CT slices, the scanning plan which returns the optimal 3-D) reconstruction of a bone segment from in vivo acquired CT images. An optimization algorithm based on a Discard-Insert-Exchange technique has been developed. In the proposed method the optimal scanning sequence is searched by minimizing the overall reconstruction error of a two-dimensional (2-D) prescanning image: an anterior-posterior (AP) X-ray projection of the bone segment. This approach has been validated in vitro on three different femurs. The 3-D reconstruction errors obtained through the optimization of the scanning plan on the 2-D) prescanning images and on the corresponding 3-D data sets have been compared. Two-dimensional and 3-D data sets have been reconstructed by linear interpolation along the longitudinal axis. Results show that direct 3-D optimization yields root mean square reconstruction errors which are only 4%-7% lower than the 2-D-optimized plan, thus proving that 2-D-optimization provides a good suboptimal scanning plan for 3-D reconstruction. Further on, 3-D reconstruction errors given by the optimized scanning plan and a standard radiological protocol for long bones have been compared. Results show that the optimized plan yields 20%-50% lower 3-D reconstruction errors.

Algorithms↗

PubMed1998

An evaluation of exact and approximate 3-D reconstruction algorithms for a high-resolution, small-animal PET scanner.

MicroPET is a low-cost, high-resolution positron emission tomography (PET) scanner designed for imaging small animals. MicroPET operates exclusively without septa, acquiring fully three-dimensional (3-D) data sets. The performance of the projection-reprojection (3DRP), variable axial rebinning (VARB), single slice rebinning (SSRB), and Fourier rebinning (FORE) methods for reconstruction of microPET data were evaluated. The algorithms were compared with respect to resolution, noise variance, and reconstruction time. Results suggested that the 3DRP algorithm gives the best combination of resolution and noise performance in 9 min of reconstruction time on a Sun UltraSparc I workstation. The FORE algorithm provided the most acceptable accelerated method of reconstruction, giving similar resolution performance with a 10%-20% degradation in noise variance in under 2 min. Significant degradation in the axial resolution was measured with the VARB and SSRB methods, offsetting the decrease in reconstruction time achieved with those methods. In-plane angular mashing of the 3-D data before reconstruction led to a 50% reduction in reconstruction time but also introduced unacceptable tangential blurring artifacts. This thorough evaluation of analytical 3-D reconstruction techniques allowed for optimal selection of a reconstruction method for the diverse range of microPET applications.

Algorithms↗

PubMed2000

Single-slice rebinning reconstruction in spiral cone-beam computed tomography.

At the advent of multislice computed tomography ICT) a variety of approximate cone-beam algorithms have been proposed suited for reconstruction of small cone-angle CT data in a spiral mode of operation. The goal of this study is to identify a practical and efficient approximate cone-beam method, extend its potential for medical use, and demonstrate its performance at medium cone-angles required for area detector CT. We will investigate two different approximate single-slice rebinning algorithms for cone-beam CT: the multirow Fourier reconstruction (MFR) and an extension of the advanced single-slice rebinning method (ASSR), which combines the idea of ASSR with a z-filtering approach. Thus, both algorithms, MFR and ASSR, are formulated in the framework of z-filtering using optimized spiral interpolation algorithms. In each view, X-ray samples to be used for reconstruction are identified, which describe an approximation to a virtual reconstruction plane. The performance of approximate reconstruction should improve as the virtual reconstruction plane better fits the spiral focus path. The image quality of the respective reconstruction will be assessed with respect to image artifacts, spatial resolution, contrast resolution, and image noise. It turns out that the ASSR method using tilted reconstruction planes is a practical and efficient algorithm, providing image quality comparable to that of a single-row scanning system even with a 46-row detector at a table feed of 64 mm. Both algorithms tolerate any table feed below the maximum value associated to the detector height. Due to the z-filter approach, all detector data sampled can be used for image reconstruction.

Algorithms↗

PubMed1998

Bone mineral assessments in the calcaneus after anterior cruciate ligament injury. An investigation of 92 male patients before and two years after reconstruction or revision surgery.

The aim of this study was to assess the Bone Mineral Areal mass (BMA) in the calcaneus of male patients with unilateral anterior cruciate ligament (ACL) injury before and after reconstruction and to assess whether the BMA ratio or the BMA of the injured and uninjured side correlated with the level of activity, functional performance or the time period between the injury and the reconstruction. Ninety-two male patients with unilateral ACL injury were included in the study. The BMA was analysed immediately prior to surgery: a median of 11 (2-192) months after the injury in 30 patients aged 26 (15-41) years scheduled for primary ACL reconstruction (Group A). Forty-nine patients aged 29 (18-49) years had their BMA analysed a median of 24 (23-29) months after the primary ACL reconstruction (Group B). Thirteen patients aged 27 (21-39) years had their BMA analysed a median of 24 (20-45) months after ACL revision surgery (Group C). The median BMA ratio (injured side/uninjured side) was 96 (88-105)% in Group A, 96 (86-118)% in Group B and 95 (83-111)% in Group C. In all three groups, the median BMA value in the calcaneus was significantly lower on the injured side compared with the uninjured side (P=0.001, P=0.0003, P=0.01 in Groups A, B and C, respectively). The time period between the injury and the reconstruction neither correlated with the BMA ratio nor the BMA of the injured or the uninjured side in Group A. The level of activity as measured by the Tegner activity level and the functional performance as measured by the one-leg-hop quotient did not correlate with the BMA ratio in any of the groups. In the 49 patients with a primary ACL reconstruction (Group B), the post-operative Tegner activity level correlated with the BMA, on both the injured and uninjured side (P=0.0003, P=0.0005, respectively), when the BMA was assessed two years after the index operation. Male patients with unilateral ACL injury had a significantly lower BMA in the calcaneus on the injured side compared with the uninjured side before primary reconstruction, two years after primary reconstruction and two years after revision surgery. The time period between the injury and the index operation did not correlate with the BMA. A high level of activity correlated with the BMA on both the injured and the uninjured side two years after primary reconstruction.

Absorptiometry, Photon↗

PubMed2003

General surface reconstruction for cone-beam multislice spiral computed tomography.

A new family of cone-beam reconstruction algorithm, the General Surface Reconstruction (GSR), is proposed and formulated in this paper for multislice spiral computed tomography (CT) reconstructions. It provides a general framework to allow the reconstruction of planar or nonplanar surfaces on a set of rebinned short-scan parallel beam projection data. An iterative surface formation method is proposed as an example to show the possibility to form nonplanar reconstruction surfaces to minimize the adverse effect between the collected cone-beam projection data and the reconstruction surfaces. The improvement in accuracy of the nonplanar surfaces over planar surfaces in the two-dimensional approximate cone-beam reconstructions is mathematically proved and demonstrated using numerical simulations. The proposed GSR algorithm is evaluated by the computer simulation of cone-beam spiral scanning geometry and various mathematical phantoms. The results demonstrate that the GSR algorithm generates much better image quality compared to conventional multislice reconstruction algorithms. For a table speed up to 100 mm per rotation, GSR demonstrates good image quality for both the low-contrast ball phantom and thorax phantom. All other performance parameters are comparable to the single-slice 180 degrees LI (linear interpolation) algorithm, which is considered the "gold standard." GSR also achieves high computing efficiency and good temporal resolution, making it an attractive alternative for the reconstruction of next generation multislice spiral CT data.

Algorithms↗