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Parallel computations on pedigree data through mapping to configurable computing devices.

Pedigree data structures have a number of applications in genetics, including the estimation of allelic or haplotype probabilities in humans and agricultural species, and the estimation of breeding values in agricultural species. Sequential algorithms for general purpose CPU-based computers are commonly used, but are inadequate for some tasks on large data sets. We show that pedigree data can be directly represented on Field Programmable Gate Arrays (FPGA), allowing highly efficient massively parallel simulation of the flow of genes. Operating on the whole pedigree in parallel, the transmission of genes can occur for all individuals in a single clock cycle. By using FPGA, the algorithms to estimate inbreeding coefficients and allelic probabilities are shown to operate hundreds to thousands of times faster than the corresponding sequentially based algorithms. Where problems can be largely represented in an integer form, FPGA provide an efficient platform for computations on pedigree data.

Algorithms↗

Computer aided analysis of additional chromosome aberrations in Philadelphia chromosome positive acute lymphoblastic leukaemia using a simplified computer readable cytogenetic notation.

BACKGROUND: The analysis of complex cytogenetic databases of distinct leukaemia entities may help to detect rare recurring chromosome aberrations, minimal common regions of gains and losses, and also hot spots of genomic rearrangements. The patterns of the karyotype alterations may provide insights into the genetic pathways of disease progression. RESULTS: We developed a simplified computer readable cytogenetic notation (SCCN) by which chromosome findings are normalised at a resolution of 400 bands. Lost or gained chromosomes or chromosome segments are specified in detail, and ranges of chromosome breakpoint assignments are recorded. Software modules were written to summarise the recorded chromosome changes with regard to the respective chromosome involvement. To assess the degree of karyotype alterations the ploidy levels and numbers of numerical and structural changes were recorded separately, and summarised in a complex karyotype aberration score (CKAS). The SCCN and CKAS were used to analyse the extend and the spectrum of additional chromosome aberrations in 94 patients with Philadelphia chromosome positive (Ph-positive) acute lymphoblastic leukemia (ALL) and secondary chromosome anomalies. Dosage changes of chromosomal material represented 92.1% of all additional events. Recurring regions of chromosome losses were identified. Structural rearrangements affecting (peri)centromeric chromosome regions were recorded in 24.6% of the cases. CONCLUSIONS: SCCN and CKAS provide unifying elements between karyotypes and computer processable data formats. They proved to be useful in the investigation of additional chromosome aberrations in Ph-positive ALL, and may represent a step towards full automation of the analysis of large and complex karyotype databases.

Adolescent↗

Single-photon emission computed tomography gallium imaging versus computed tomography: predictive value in patients undergoing high-dose chemotherapy and autologous stem-cell transplantation for non-Hodgkin's lymphoma.

PURPOSE: To evaluate the predictive value of computed tomography (CT) scanning and single-photon emission computed tomography (SPECT) gallium (Ga) scanning in the disease-free survival of patients receiving high-dose chemotherapy and autologous stem-cell transplantation for non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: One hundred forty-three patients undergoing transplant for NHL underwent CT scanning of chest, abdomen, and pelvis, and a SPECT Ga scan before transplantation and at day + 100 after transplant. The failure-free survival (FFS) by scan result was analyzed. RESULTS: In the diffuse aggressive lymphoma patients, the 1-year FFS for patients having a positive SPECT Ga scan at day + 100 was 15% compared with a 3-year FFS of 47% for those with a negative scan (P < .001). Patients with a positive CT scan at day + 100 had a 36% 3-year FFS, and those with a negative CT scan had a 39% 3-year FFS (P = not significant [NS]). An analysis of the combination of CT scan and SPECT Ga scan results at day + 100 posttransplant demonstrated a 3-year FFS of 14% if they were both abnormal; if the CT was positive and Ga was negative, the 3-year FFS was 68%; positive Ga with a negative CT was 25%; and both negative was 34% (P = .0015). For the patients with follicular NHL, those with a positive SPECT Ga at day + 100 had a 14% 1-year FFS compared with those with a negative scan, who had a 45% 3-year FFS (P < .001). In the follicular NHL patients, the 3-year FFS of those with a positive CT was 17% compared with a 64% 3-year FFS for patients with a negative CT scan (P < .001). CONCLUSION: The use of SPECT Ga scan at day + 100 posttransplant for evaluation of disease activity in patients with diffuse aggressive NHL was highly predictive of eventual outcome and was more predictive than the CT scan results. However, for patients with follicular NHL, the addition of SPECT Ga scanning to CT scanning did not add substantially to the evaluation of transplant outcome.

Adolescent↗

Results of computed tomography-based computer-assisted stereotactic resection of metastatic intracranial tumors.

Forty-four patients underwent 45 computer-assisted stereotactic resections of intracranial metastases from various centrally located and deep-seated regions using methods described in this report and elsewhere. Gross total removal was achieved in all cases. There was no postoperative mortality (within 30 days). Postoperative neurological examinations revealed that: (a) of 26 who presented with preoperative neurological deficits, 13 were normal postoperatively, 7 were improved, 3 were unchanged, and 3 were worse; (b) 5 of 5 patients who had increased intracranial pressure preoperatively were normal postoperatively; and (c) 3 of 3 patients who had increased intracranial pressure and neurological deficit preoperatively were neurologically normal postoperatively. Nine of 10 patients who were neurologically normal preoperatively were normal postoperatively, and the other had transient upper extremity weakness after resection of a lesion in the contralateral motor strip. The 1-year survival in this group of patients was 62.5%. No local recurrence was noted in any patient. Computer-assisted stereotactic resection permits accurate localization of metastatic lesions and gross total resection from difficult locations with acceptable levels of morbidity.

Adult↗

Usefulness of technetium-99m methoxyisobutylisonitrile single-photon emission computed tomography and computed tomography in the evaluation of cervical lymph node metastasis.

The aim of this study was to compare the effectiveness of technetium-99m methoxyisobutylisonitrile ((99m)Tc-MIBI) single-photon emission computed tomography (SPECT) and computed tomography (CT) in evaluating cervical lymph node metastasis of head and neck cancer. Histopathologic results of 166 cervical lymph node levels in 31 neck-dissected patients were compared with pre-operative CT and (99m)Tc-MIBI SPECT findings about cervical lymph node metastasis, retrospectively. Sensitivity, specificity and predictability of CT and (99m)Tc-MIBI SPECT were 68.2, 93.1 and 89.8 per cent and 59.1, 87.5 and 83.7 per cent, respectively. When analysing CT and(99m)Tc-MIBI SPECT together, sensitivity and specificity were 86.4 and 99.3 per cent, respectively. The combined use of (99m)Tc-MIBI SPECT and CT could increase the accuracy of cervical lymph node metastases detection, compared with separate use of either (99m)Tc-MIBI SPECT or CT.

Adult↗

Osseous abnormalities of the mandibular condyle: diagnostic reliability of cone beam computed tomography compared with helical computed tomography based on an autopsy material.

OBJECTIVES: We compared the diagnostic reliability of cone beam computed tomography (3DX) and helical computed tomography (helical CT) for the detection of osseous abnormalities of the mandibular condyle, using macroscopic observations as the gold standard. METHODS: Twenty-one temporomandibular joint autopsy specimens underwent imaging with 3DX and helical CT. The specimens were macroscopically evaluated for cortical erosion or osteophytosis and sclerosis. The images were independently assessed for the same osseous abnormalities. Observations with the two imaging modalities were compared with the macroscopic observations using the McNemar test. RESULTS: According to the macroscopic observations, 10 of the 21 mandibular condyles and one fossa showed osseous abnormalities. 3DX detected abnormalities in eight of these condyles and helical CT identified abnormalities in seven, giving a sensitivity of 0.80 for 3DX and 0.70 for helical CT. The specificity of the condyle assessment was 1.0 for both 3DX and helical CT and hence, the accuracy was 0.90 and 0.86, respectively. No significant differences were detected between the 3DX and helical CT for assessment of osseous abnormalities of the mandibular condyle (P=0.286). CONCLUSIONS: The cone beam CT equipment 3DX is a dose-effective and a cost-effective alternative to helical CT for the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

Adult↗

Comparison of ultrasonography, computed tomography, and single-photon emission computed tomography for the detection and localization of canine insulinoma.

Accurate preoperative detection, localization, and staging of the primary tumor and metastases are essential for the selection of appropriate candidates for surgery. In dogs with insulinoma, preoperative assessment usually is performed with transabdominal ultrasonography (US). There are no reports on the use of computed tomography (CT) for this purpose. The preoperative use of somatostatin receptor scintigraphy (SRS) recently has been advocated for the identification of insulinoma and gastrinoma in dogs, but its accuracy remains to be established. In this report US, CT, and single-photon emission computed tomography (SPECT) with [111In-DTPA-D-Phe1]-octreotide (a specific form of SRS) were compared for their effectiveness in detecting and localizing primary and metastatic insulinoma in dogs. Findings at surgery or postmortem examination served as control. Of 14 primary insulinomas, 5, 10, and 6 were correctly identified by US, CT, and SPECT, respectively. No lymph node metastases were detected by US or SPECT. CT identified 2 of 5 lymph node metastases but also identified 28 false-positive lesions. Two of 4 livers were found to be positive for metastases by 1 of the imaging techniques. US can be used for the initial evaluation of dogs with hypoglycemia. Although CT identifies most primary tumors, intraoperative inspection and palpation of the pancreas is still superior. SPECT appears as effective as US and CT in detecting insulinomas. Future developments in preoperative imaging techniques might improve current methods of canine insulinoma detection.

Animals↗

Computational flow dynamics in abdominal aortic aneurysm using multislice computed tomography.

Following the introduction of a new multislice computed tomography (MSCT) scanner, it has become possible to produce high-speed CT angiography (CTA), the preferred method for imaging in emergent abdominal vascular conditions. Unlike catheter angiography, multislice CTA not only depicts the vessels but also allows perfusion in adjacent organs to be assessed. To make the most effective diagnostic use of multi-detector row CTA and three-dimensional image post-processing, radiologists must be familiar with the optimal CTA protocols and the typical CT findings in various emergent vascular conditions using computational flow dynamics (CFD). This article describes a technical approach to estimating the blood flow state of human abdominal aortic aneurysms (AAA) in more detail by constructing realistic three-dimensional (3D) vessel models using CFD methods, focusing on pre- and postoperative cases.

Aged↗

Technetium-99m methoxy-isobutyl-isonitrile chest single photon emission computed tomography to detect mediastinal lymph node metastasis in patients with non-small cell lung cancer: comparison with computed tomography.

This study evaluated the clinical role of Tc-99m-methoxyisobtylisonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) of the chest in the detection of mediastinal lymph node (MLN) metastasis in patients with non-small cell lung cancer (NSCLC). Twenty-five patients with proven NSCLC were enrolled in this study. Each of the patients received computed tomography (CT) of the chest and Tc-MIBI SPECT of the chest for presurgical staging. A postsurgical pathologic diagnosis was made and these patients were evaluated for the study of mediastinal lymph nde (MLN) involvement. Meanwhile, 10 volunteers also accepted Tc-MIBI SPECT of the chest for comparison. The results showed that the diagnostic sensitivity, specificity and accuracy of Tc-MIBI chest SPECT were 81.8%, 85.7% and 84% and for chest CT they are 36.3%, 85.7% and 64%, respectively. Our results indicated that Tc-MIBI chest SPECT was more sensitive and accurate than chest CT in the evaluation and detection of MLN involvement in the NSCLC patients.

Adenocarcinoma↗

Detection of cervical lymph node metastases of nasopharyngeal carcinomas with technetium-99m tetrofosmin single photon emission computed tomography and comparison with computed tomography.

The purpose of this study was to evaluate the usefulness of technetium-99m tetrofosmin (Tc-99m TF) single photon emission computed tomography (SPECT) in the detection of cervical lymph node (LN) metastasis in nasopharyngeal carcinomas (NPC), and to compare Tc-99m TF SPECT results with computed tomography (CT) findings. Fifty patients with biopsy-proven NPC and suspected cervical LN metastases underwent head and neck Tc-99m TF SPECT and CT to detect cervical LN metastases. Cervical LN metastases of 40 patients were confirmed by histopathological examination of biopsy samples. For 22 LN lesions with discordant results between Tc-99m TF SPECT and CT, Tc-99m TF SPECT could correctly detect 4 metastatic and 7 benign LN lesions while CT could correctly detect 5 metastatic and 6 benign LN lesions. Agreement positive results of Tc-99m TF SPECT and CT could correctly detect all of the 18 metastatic LN lesions. Tc-99m TF SPECT has a better specificity but a lower sensitivity for detecting cervical LN metastases in NPC when compared with CT. The combined use of Tc-99m TF SPECT and CT could significantly increase the accuracy of detect cervical LN metastases in NPC compared with the single use of either Tc-99m TF SPECT or CT.

Adult↗

A methodological tool for computer-assisted surgery interface design: its application to computer-assisted pericardial puncture.

Computer Assisted Surgery systems are becoming more and more prevalent. Design processes currently used, pay only a small attention to the surgeon's interaction. To address this lack in design, we propose the OP-a-S notation: OP-a-S modeling of a system adopts an interaction-centered point of view and highlights the links between the real world and the virtual world. Based on an OP-a-S modeling, predictive usability analysis can be performed by considering the ergonomic property. We illustrate our method on the retro-design of a computer assisted surgical application, CASPER.

Computer Simulation↗

Detection of cervical lymph node metastases in nasopharyngeal carcinomas: comparison between technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography.

The aim of this study was to compare the effectiveness of technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) and computed tomography (CT) of head and neck in evaluating cervical lymph node (LN) metastasis in nasopharyngeal carcinomas (NPC). Fifty NPC patients with suspected cervical LN metastases underwent Tc-99m MIBI SPECT and CT of the head and neck to evaluate cervical LN metastases. Among the 50 patient.s cervical LN lesion were confirmed by biopsy histopathological results in 40 patients. For 22 LN lesions with discordant results between Tc-99m MIBI SPECT and CT Tc-99m MIBI SPECT could correctly detect 5 metastatic and 7 benign LN lesions, while could correctly detect 5 metastatic and 6 benign LN lesions. Tc-99m MIBI SPECT and CT could correctly detect all of the 18 metastatic LN lesions. Tc-99m MIBI SPECT showed a better specificity but a lower sensitivity for detecting cervical LN metastases in NPC when compared with CT. The combined use of Tc-99m MIBI SPECT and CT could increase the accuracy, compared with the single use of either Tc-99m MIBI SPECT or CT, to detect cervical LN metastases in NPC.

Adult↗

Comparison of technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography to detect recurrent or residual nasopharyngeal carcinomas after radiotherapy.

The diagnostic accuracy of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) of head and neck to differentiate between recurrent or residual nasopharyngeal carcinomas (NPC) and benign lesions after radiotherapy was evaluated, and compared with computed tomography (CT). Thirty-six NPC patients 4 months after radiotherapy underwent Tc-MIBI SPECT and CT of head and neck, as well as histopathological examination of nasopharyngeal biopsies. Based on the biopsy results, the sensitivity, specificity, and accuracy of CT were 73%, 88%, and 83%, respectively. The sensitivity, specificity, and accuracy of Tc-MIBI SPECT were 64%, 96%, and 86%, respectively. The sensitivity, specificity, and accuracy of combined Tc-MIBI SPECT and CT were 100%, 88%, and 92%, respectively. Tc-MIBI SPECT had a better specificity and a lower sensitivity to differentiate benign lesions from recurrent/residual NPC when compared with CT The combined use of CT and Tc-MIBI SPECT significantly increased accuracy compared with the single use of either Tc-MIBI SPECT or CT to differentiate benign lesions recurrent/residual NPC.

Adolescent↗

Differentiating recurrent or residual nasopharyngeal carcinomas from post-radiotherapy changes with 18-fluoro-2-deoxyglucose positron emission tomography and thallium-201 single photon emission computed tomography in patients with indeterminate computed tomography findings.

The aim of this study was to compare the accuracy of 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and thallium-201 (Tl-201) single photon emission computed tomography (SPECT) in differentiating recurrent/residual nasopharyngeal carcinomas (NPC) from post-radiotherapy (RT) changes in patients with indeterminate computed tomography (CT) findings. Twenty NPC patients with indeterminate CT findings were included at least 4 months after RT. CT, FDG-PET, Tl-201 SPECT and biopsy were performed within 1 week. The final diagnoses were based on biopsy findings and clinical follow-up for at least 6 months. For differentiating recurrent/residual NPC from post-RT changes in patients with indeterminate CT findings, the sensitivity, specificity and accuracy of FDG-PET were 100.0%, 92.3% and 96.0%, respectively. The sensitivity, specificity and accuracy of Tl-201 SPECT were 91.7%, 92.3% and 92.0%, respectively. Based on this study's findings, we can conclude FDG-PET is more sensitive but equally specific as Tl-201 SPECT is differentiating recurrent/residual NPC from post-RT changes in patients with indeterminate CT findings.

Adolescent↗

Comparison of (99)mTc-methoxyisobutylisonitrile myocardial single-photon emission computed tomography and electron beam computed tomography for detecting coronary artery disease in patients with no myocardial infarction.

BACKGROUND: Previous studies have compared single-photon emission computed tomography (SPECT) and electron beam computed tomography (EBCT) in detection of coronary artery disease (CAD) in patients with myocardial infarction (MI). The purpose of this study was to compare SPECT with EBCT in detection of CAD in patients with no MI. METHODS: One hundred and forty-seven patients with suspected CAD underwent stress-rest (99)mTc-methoxyisobutylisonitrile ((99)mTc-MIBI) myocardial SPECT, cardiac EBCT and coronary angiography (CAG) within one month. Of them, 73 patients (aged 52.6 +/- 10.6 years old) with no history of MI were included in this study. Coronary artery calcium (CAC) was defined as a CT value >or= 130 HU within the boundary of coronary artery on EBCT. RESULTS: There were 35 and 38 patients with or without CAD according to CAG. Ninety-six percent of the patients with abnormal SPECT and CAC had a coronary arteries stenosis >or= 50%, and 90.9% patients with normal SPECT and EBCT showed no CAD. The sensitivity of SPECT and EBCT in detection of CAD was comparable, and the specificity of SPECT (92.1%) was significantly higher than that of EBCT (55.3%) (P < 0.005). For the detection of individual coronary artery stenosis, both sensitivity and specificity of SPECT (75.0% and 93.7%) were significantly higher than those of EBCT (53.3% and 76.7%) (P < 0.025 and P < 0.005, respectively). In patients without chest pain, the sensitivity and specificity of SPECT (76.9% and 91.4%) were significantly higher than those of EBCT (23.1% and 69.0%) in detection of a coronary artery stenosis of >or= 50% (P < 0.01 and P < 0.005, respectively). However, in patients with chest pain, both sensitivity and specificity of SPECT were comparable to those of EBCT. In patients or= 50% (P < 0.005), and the specificity of SPECT was comparable to that of EBCT. In patients > 45 years old, the specificity of SPECT (94.3%) was significantly higher than that of EBCT (70.5%) (P < 0.005), and the sensitivity of SPECT was comparable to that of EBCT. CONCLUSION: (99)mTc-MIBI myocardial perfusion SPECT has higher accuracy than that of EBCT in detection of CAD in patients without MI.

Adult↗

Quantitative computer-aided computed tomography analysis of sphenoid sinus anatomical relationships.

BACKGROUND: This study describes a novel computer-generated anatomic symmetry plane as a framework for the quantitative description of sphenoid sinus anatomy. The aim of this study was to (1) determine relationships and distances between a midline sphenoid reference point (called the central sphenoid point [CSP]) and lateral sphenoid wall structures and (2) assess the incidence of anterior clinoid process (ACP) pneumatization and pterygoid recess (PR) pneumatization. METHODS: Axial computed tomography (CT) scans (1-mm slice thickness) were obtained on a VolumeZoom CT scanner (Siemens Medical, Erlangen, Germany). Mathematically derived anatomic symmetry planes were created using custom postprocessing software. A standardized review of each CT scan using surgical planning software (CBYON Suite version 2.6; CBYON, Mountain View, CA) was performed. The CSP was defined as a reference point in the midline sagittal plane at the intersection of the vertical sellar face and the horizontal sellar floor. RESULTS: A total of 128 sides in 64 cadaveric specimens were available for review. The incidences of ACP pneumatization and PR pneumatization were 23.4 and 37.5%. The mean distances from the CSP to the left optic canal midpoint, the left ACP entrance point, and the left PR lateral wall were 17.2, 15.6, and 27.6 mm, respectively. The corresponding distances from the CSP on the right side were 17.3, 15.8, and 28.0 mm, respectively. Measurements from the maxillary spine to the optic canal midpoint, ACP entrance point, and PR lateral wall on each side were performed also. CONCLUSION: This approach provides both quantitative and qualitative understanding of sphenoid osteology and may be coupled with intraoperative surgical navigation to reduce the risks of sphenoid surgery. Both PR and ACP pneumatization are surprisingly common. Because the CSP-derived relationships may be referenced during endoscopic surgical navigation, they may provide greater clinical utility than traditional alternatives. This paradigm may facilitate a greater understanding of sphenoid anatomy and enhance surgical safety and precision.

Adult↗

A computer-aided diagnosis (CAD) system in lung cancer screening with computed tomography.

We evaluated a computer-aided diagnosis (CAD) system with automatic detection of pulmonary nodules for lung cancer screening with computed tomography (CT). Five hundred and eighteen participants were examined with low-dose helical CT during a lung cancer screening by three respiratory physicians according to the General Rule edited by the Japan Lung Cancer Society. Four cases were detected by CAD and pathologically diagnosed as lung cancer. We compared the detection capability of the physician and CAD in 301 participants. Three physicians determined 75/301 (24.9%) participants as "e" (suspicious of lung cancer) in consensus without CAD, while 3 participants were added to "e" with CAD. Three physicians did not independently judge as "e" in 14 (18.7%), 16 (21.3%) and 16 (21.3%) out of 75 participants. CAD could not identify 17 (22.7%) nodules of 75 participants, and all 17 were less than 6 mm in diameter. The CAD system offers a useful second opinion when physicians examine patients at lung cancer CT screenings.

Adult↗

Principles and applications of Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) technology in orthopaedics.

The principles involved in Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) technology is presented in this article. It also highlights the current advances and capability of this technology. Application of the CAD/CAM technology in orthopaedics is relatively new. Three broad areas of applications can be defined: (1) three-dimensional reconstructions of skeletal structure based on any of the imaging technique, i.e. CT scan, MRI or X-ray, to analyse, simulate, design and evaluate orthopaedic procedures without having to actually perform the surgery; (2) the production of plastic or wax models for surgeons to have global impressions and understanding of complex cases of bone and joint disorders and the possibility of using the physical models as templates to sculpt allograft pre-operatively; and (3) to design and manufacture geometrically optimal standard and customised implants. CAD/CAM technology is also rapidly developing in the field of prosthetics, orthotics and orthopaedics footwear. The advantages offered include shorter delivery time, more consistent design, quantifiable rectification and "modern" or remote manufacturing. Apart from these applied usage, the CAD/CAM technology is also an effective tool for education and training. The application of CAD/CAM technology in orthopaedics and its related fields has been shown to have tremendous potential, but may appear to be too esoteric, complex and costly at the present moment. However, with improved generality, simplicity and cost-effectiveness of the system, it will become more practical.

Computer Simulation↗