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PubMedDate not supplied

[Magnetic resonance for the study of osteosarcoma].

The authors report their experience with MR imaging in the study of osteosarcoma. Two main elements were evaluated: signal characteristics and loco-regional staging. Seventy-one patients were studied: 65 of them had central long-bone osteosarcoma, and 6 had telangiectatic long-bone osteosarcoma. T1- and T2-weighted spin-echo sequences were employed and all cases were scanned on 3 planes (sagittal, coronal, and axial). In 28 patients MR imaging was performed both before and after preoperative chemotherapy. The obtained data were compared to surgical and pathological findings. With the exception of the typical signal patterns of quite-osteoblastic osteosarcoma (which presents with low signal on both T1- and T2-weighted sequences), no particular signal features were observed which could help distinguish the different types of osteosarcoma. MR imaging is the method of choice in loco-regional staging for, in our series, it allowed a rational and adequate surgical planning. For this purpose, at least a longitudinal T1- and an axial T2-weighted images are required.

Adolescent↗
PubMedDate not supplied

PC-based multiparameter full-color display for tissue segmentation in MRI of adnexal masses.

OBJECTIVE: Our purpose was to apply full-color composite generation methods to multiparameter MRI to assess the ability of the technique to quantitatively segment clinically important anatomic and pathologic tissues. MATERIALS AND METHODS: With use of a personal computer with a 386 microprocessor and full-color (24 bit) graphics display capabilities, custom and commercially available image-processing softwares were applied to spatially aligned multiparameter SE MR image sets obtained from six patients undergoing diagnostic work-up for suspected adnexal or pelvic masses to generate intensity-based color composites. To quantitatively assess the ability of this technique to differentially segment anatomically and pathologically confirmed tissue types into unique color regions within the full-color spectrum, color image analysis was performed on the multiparameter color composites within each patient case, and the results were compared using 95% confidence intervals. RESULTS: Based on the results of pathologic correlation and color image analysis, the generation of full-color composites represents a feasible technique for compressing the diverse tissue contrast data present in multiparameter MR images of adnexal masses. CONCLUSION: With this technique, it is possible to generate composites that simultaneously display uniquely color-coded anatomic and pathologic tissue information within the context of partially natural-appearing images.

Adnexal Diseases↗
PubMedDate not supplied

Chondromyxoid fibroma of the upper thoracic spine in a 7-year-old patient. A case report and review of the literature.

BACKGROUND: We report a case of a 7-year-old white female who presented with acute, progressive bilateral lower extremity weakness over 48 h. METHODS: Case report and presentation of clinical, radiological and pathological data on a single case of chondromyxoid fibroma (CMF) of the T2 vertebral body. RESULTS: Magnetic resonance imaging of the thoracic spine revealed an extensive mass invading the lamina of the second thoracic vertebra, causing extensive cord compression and progressive neurological deterioration. Surgical resection and pathologic study of the mass revealed a CMF. CONCLUSIONS: A thorough Medline search has revealed that only 25 cases of spinal CMF have been reported, making this lesion an extremely rare bone tumor.

Child↗
PubMed2004

[3D-Visualisation of the middle ear by computer-assisted post-processing of helical multi-slice CT data].

Post-processing of CT-data allows non-invasive 3D-Visualisation of the middle ear for diagnosis and surgical planning. In this study different post-processing techniques and the clinical application of a 3D-postprocessing algorithm in a large number of patients are presented. 20 normal patients, 6 dissected temporal bones and 213 patients with suspected middle ear pathology were examined using a low-dosage Multi-Slice CT protocol. Virtual endoscopic views of the middle ear and 3D-images of the ossicles were generated using a standardised algorithm. Evaluation of the image quality was performed. The virtual views of the dissected temporal bones were compared to real views. In 32 patients high-quality 3D-models of the individual anatomical structures were generated and displayed using different visualisation techniques. The standardised and evaluated method enabled visualisation of the normal middle ear anatomy. Assessment of different pathologies, especially malformation, trauma, implants and postoperative alterations, was facilitated. The high-quality 3D-models allowed precise imaging of the anatomical structures. 3D-Visualisation of the middle ear using CT-data is beneficial for radiological diagnosis and surgical planning in cases of complex middle ear pathology as a complementary examination technique.

Adolescent↗
PubMed2005

Rapid prototyping to create vascular replicas from CT scan data: making tools to teach, rehearse, and choose treatment strategies.

Our goal was to develop and prove the accuracy of a system that would allow us to re-create live patient arterial pathology. Anatomically accurate replicas of blood vessels could allow physicians to teach and practice dangerous interventional techniques and might also be used to gather basic physiologic information. The preparation of replicas has, until now, depended on acquisition of fresh cadaver material. Using rapid prototyping, it should be able to replicate vascular pathology in a live patient. We obtained CT angiographic scan data from two patients with known arterial abnormalities. We took such data and, using proprietary software, created a 3D replica using a commercially available rapid prototyping machine. From the prototypes, using a lost wax technique, we created vessel replicas, placed those replicas in the CT scanner, then compared those images with the original scans. Comparison of the images made directly from the patient and from the replica showed that with each step, the relationships were maintained, remaining within 3% of the original, but some smoothing occurred in the final computer manipulation. From routinely obtainable CT angiographic data, it is possible to create accurate replicas of human vascular pathology with the aid of commercially available stereolithography equipment. Visual analysis of the images appeared to be as important as the measurements. With 64 and 128 slice detector scanners becoming available, acquisition times fall enough that we should be able to model rapidly moving structures such as the aortic root.

Angiography↗
PubMed1991

Monte Carlo modelling of light propagation in breast tissue.

Light transport in three-dimensional plane-parallel tissue slabs has been modelled by Monte Carlo analogue simulation. The model design has allowed the study of transmission properties that are pertinent to imaging systems for the detection of breast cancer. An important aspect of the investigations is that they make use of data obtained from quantitative measurements of light scattering and absorption in normal and pathological breast tissues. It is shown that an imaging technique which used a raster scanning laser and detector arrangement and plane-parallel compression of the breast could have considerable advantages in terms of improved transmittance, spatial unsharpness and contrast. Time-of-flight gating of images is also found to be beneficial provided that the light intensities after temporal filtering remain adequate.

Breast↗
PubMed1995

Islet cell tumors of the pancreas: pathologic-imaging correlation among size, necrosis and cysts, calcification, malignant behavior, and functional status.

OBJECTIVE: The purpose of our study was to correlate the imaging and pathologic features of islet cell tumors with regard to tumor size, necrosis and cysts, calcification, malignant behavior, and functional status. MATERIALS AND METHODS: We retrospectively reviewed the clinical, pathologic, and imaging features of all 133 cases of pathologically proved islet cell tumors of the pancreas seen at the Armed Forces Institute of Pathology. Clinical data, including the patients' symptoms and serologic characteristics, were used to distinguish hyperfunctioning tumors (those causing symptoms related to elevated serum polypeptide levels) from nonhyperfunctioning tumors; hyperfunctioning tumors were divided further into insulin-producing and non-insulin-producing types. All patients had at least one cross-sectional imaging study, including CT (n = 118), sonography (n = 42), or MR imaging (n = 22). Clinical, pathologic, and imaging features were evaluated and correlated with tumor size, necrosis and cysts, calcification, local invasion, vascular invasion, metastases, and functional status. RESULTS: Islet cell tumors with areas of necrosis or cystic change found pathologically and on imaging studies (56/133) were larger (8.4 cm in mean transverse diameter) than homogeneous solid lesions (2.9 cm in mean transverse diameter) and were predominantly non-insulin producing (48/56) and nonhyperfunctioning (36/56). Of the 43 insulinomas, 35 were small (2.2 cm in mean transverse diameter), solid, and homogeneous. Larger size also was associated with calcification and malignant behavior, including local invasion, vascular invasion, and distant metastases. CONCLUSION: Our findings show that cystic and necrotic islet cell tumors are usually non-insulin-producing and nonhyperfunctioning neoplasms and larger than the typically solid and small insulinomas. Calcification, local invasion, vascular invasion, and metastatic disease are more commonly seen with larger neoplasms.

Adenoma, Islet Cell↗
PubMed1991

[Image diagnosis of polypoid lesions of the gallbladder].

Between 1980 and 1990, 120 cases of polypoid lesions of the gallbladder (GBPL), confirmed surgically and pathologically, were evaluated comprehensively with each kind of image examinations. 110 cases of B-US data were dealt with multiple stepwise regression analysis, and three carcinoma risk factors (size & location of the lesion, age of the patient) were found. The results of Mahalanobis' discriminant analysis showed that the conformity rates of retrospective test (80 cases) and prospective test (30 cases) were 94% and 90%, respectively. In addition, we put forward our own clinical classification of GBPL according to the surgical and pathological data and the need of clinical practice.

Adenocarcinoma↗
PubMed1993

Clinical application of three-dimensional sonography in internal medicine.

Three-dimensional sonography represents a development of non-invasive diagnostic imaging by real-time two-dimensional sonography. The use of transparent rotating scans, comparable to a block of glass, generates a three-dimensional effect. The first clinical application of this technique was in the field of gynecology and obstetrics, namely in prenatal diagnostics. In this study we describe its first application in internal medicine. In preliminary examinations on healthy volunteers we obtained specific processing data for optimal imaging results. This was followed by secondary examinations on 123 patients who had previously undergone conventional sonography with pathological findings. In more than 75% of the cases examined we found an optimal reproduction of sonographic findings with respect to the evaluation criteria developed by us for the three dimensional imaging of processed data. With the inclusion of measurement parameters such as distance determination and volume measurements the data gathered will allow the generation of reproducible results. Future studies will confirm the value of this method in diagnostic imaging.

Adult↗
PubMed2006

Pattern of T2 hypointensity associated with ring-enhancing brain lesions can help to differentiate pathology.

Ring-enhancing lesions seen on MR images can occur with a variety of etiologies. Some ring-enhancing lesions have hypointense rims peripherally on T2-weighted MR images. In this study, we examined whether T2 hypointense rims were associated with specific pathologies. A search for ring-enhancing lesions on MR images obtained from 1996 to 2004 was performed, and revealed 221 patients with MRI findings of ring enhancement. The pattern of T2 hypointensity (arc or rim) corresponding with ring enhancement was recorded. In addition, we analyzed other imaging characteristics, including signal on diffusion-weighted images, central homogeneity on T2 and multiplicity of lesions. We then reviewed clinical data on the patients to ascertain the diagnosis for each examination. The most common associated pathologies in our study were gliomas (40%), metastases (30%), abscesses (8%) and multiple sclerosis (MS; 6%). Hypointense borders on T2-weighted images were present in 67% of lesions in the form of a rim in 40% and an arc in 60%. Abscesses had the highest percentage of hypointense rims. Metastases and gliomas more commonly had arcs, and MS lesions were divided between rims and arcs. Abscesses and MS lesions were more commonly homogeneous centrally, compared to gliomas and metastases. Additionally, abscesses were more often bright on diffusion imaging than the other pathologies. As expected, abscesses and MS lesions were usually multiple, whereas metastases were typically multiple in approximately 50% of the patients; gliomas were generally solitary. Trends in T2 hypointensity may aid in distinguishing among etiologies of ring-enhancing lesions, although there is overlap between the MR appearance of these various pathologies.

Brain↗
PubMed2006

Durability of portal venous reconstruction following resection during pancreaticoduodenectomy.

Venous resection and reconstruction is becoming more common during pancreaticoduodenectomy (PD). There are multiple options for reconstruction of the mesenteric venous system ranging from primary repair to grafting with autologous or synthetic material. Few studies report on the patency rates and long-term morbidity of these repairs. We sought to describe our experience with venous reconstruction during PD with specific attention to patency and long-term morbidity and mortality. Thrombosis rates of mesenteric venous reconstruction during PD are low, with low associated morbidity. In this retrospective cohort, clinical, operative, and pathologic data were collected from consecutive patients for 1988 through 2003. Graft patency on follow-up imaging studies was determined, and short- as well as long-term morbidity and mortality were recorded. Sixty-four patients underwent PD with venous resection/reconstruction from 1988 through 2003. Mean patient age was 63 years, with pancreatic ductal adenocarcinoma as the pathology in 88%. Reconstruction consisted of primary lateral venorrhaphy in 29 (45%), PTFE graft in 18 (28%), primary end-to-end repair in 13 (20%), and autologous vein graft in 4 (6%). There was one perioperative death (2%). Follow-up imaging to assess patency was available for a mean of 12.2 months postoperatively. Eleven thromboses were diagnosed at a mean of 11.9 months. Three thromboses (5%) were noted within 30 days and full anticoagulation was chosen. Fifty-three percent of patients received anticoagulation with aspirin, warfarin, or clopidogrel based upon surgeon preference. There was no difference in thrombosis rates between those receiving anticoagulation and those who did not (P=0.65). In those patients with thrombosis outside the acute time period, morbidity was limited to ascites in three patients and splenic vein thrombosis with uncomplicated esophageal varices in another patient. Mesenteric venous resection and reconstruction during PD has a high patency rate, and those reconstructions that do thrombose are associated with a low morbidity. The majority of reconstruction thromboses that occurred late were associated with recurrence.

Carcinoma, Pancreatic Ductal↗
PubMed2001

Tumoral calcinosis of the spine: a study of 21 cases.

STUDY DESIGN: A retrospective study was conducted to investigate 21 patients found during spinal surgery to have paraspinal masses of dystrophic calcification (tumoral calcinosis). OBJECTIVES: To determine the magnetic resonance imaging characteristics of this disorder, and to document the associated spinal pathology. SUMMARY OF BACKGROUND DATA: Tumoral calcinosis usually is associated with hereditary disorders of calcium metabolism or renal dialysis. It also occurs in degenerated tissues in the absence of systemic disorders. Characteristically, calcific masses in the appendicular skeleton are visible on plain radiographs. Tumoral calcinosis has only rarely been reported in the spine. Documented patients have had an obvious calcific mass, and almost always the disorder has existed in other locations as well. Careful histologic study of specimens removed during spinal surgery suggests that tumoral calcinosis is common in the spine and usually is secondary to preexisting pathology. METHODS: This study involved 21 patients with lesions of tumoral calcinosis identified by histopathologic analysis of specimens removed during spinal surgery. The magnetic resonance images and the plain radiographs of the patients were reviewed and correlated with their clinical histories. RESULTS: In all the patients, the lesion of tumoral calcinosis was associated with a mass lesion seen on magnetic resonance imaging. Calcific masses were not apparent on plain films. In no case was the mass diagnosed before surgery as tumoral calcinosis. The magnetic resonance imaging changes were variously misinterpreted as neoplasms, infections, extruded disc material, or cysts. The observed features of tumoral calcinosis were those of an extradural mass showing a heterogeneous mixed-signal lesion that was identical on T1- and T2-weighted images. Characteristically, gadolinium did not enhance the lesions. CONCLUSIONS: Awareness of tumoral calcinosis of the spine may prevent unwarranted diagnoses of a more serious lesion in patients with characteristic magnetic resonance imaging changes. Also, this awareness may prevent pathologists from interpreting lesional tissue as nondiagnostic when other diagnoses are suspected clinically. This process may be a manifestation of degenerative spinal disease that has become so dominant that the underlying processes are obscured.

Adult↗
PubMed2005

Correlation of proton MR spectroscopic imaging with gleason score based on step-section pathologic analysis after radical prostatectomy.

PURPOSE: To determine whether hydrogen 1 magnetic resonance (MR) spectroscopic imaging can be used to predict aggressiveness of prostate cancer. MATERIALS AND METHODS: All patients gave informed consent according to an institutionally approved research protocol. A total of 123 patients (median age, 58 years; age range, 40-74 years) who underwent endorectal MR imaging and MR spectroscopic imaging between January 2000 and December 2002 were included. MR imaging and spectroscopy were performed by using combined pelvic phased-array and endorectal probe. Water and lipids were suppressed, and phase-encoded data were acquired with 6.2-mm resolution. Voxels in the peripheral zone were considered suspicious for cancer if (Cho + Cr)/Cit was at least two standard deviations above the normal level, where Cho represents choline-containing compounds, Cr represents creatine and phosphocreatine, and Cit represents citrate. Correlation between metabolite ratio and four Gleason score groups identified at step-section pathologic evaluation (3 + 3, 3 + 4, 4 + 3, and > or =4 + 4) was assessed with generalized estimating equations. RESULTS: Data from 94 patients were included. Pathologic evaluation was used to identify 239 lesions. Overall sensitivity of MR spectroscopic imaging was 56% for tumor detection, increasing from 44% in lesions with Gleason score of 3 + 3 to 89% in lesions with Gleason score greater than or equal to 4 + 4. There was a trend toward increasing (Cho + Cr)/Cit with increasing Gleason score in lesions identified correctly with MR spectroscopic imaging. Tumor volume assessed with MR spectroscopic imaging increased with increasing Gleason score. CONCLUSION: MR spectroscopic imaging measurement of prostate tumor (Cho + Cr)/Cit and tumor volume correlate with pathologic Gleason score. There is overlap between MR spectroscopic imaging parameters at various Gleason score levels, which may reflect methodologic and physiologic variations. MR spectroscopic imaging has potential in noninvasive assessment of prostate cancer aggressiveness.

Adult↗
PubMed2001

Polyurethane real-size models used in planning complex spinal surgery.

STUDY DESIGN: The application of polyurethane real-size models for planning and performing complex spinal surgery is described. OBJECTIVE: To determine the feasibility of using polyurethane real-size models to plan osteotomies, resections, and designs of custom-made spinal implants in complex spinal surgery. SUMMARY OF BACKGROUND DATA: In selected patients with complex spinal pathology, exact planning of the surgical procedure is not possible using current imaging methods. In these cases, real-size spinal models would be desirable to enhance pre- and perioperative planning by visual and tactile feedback, and to improve the production of custom-made spinal implants. METHODS: A real-size spinal model of six patients was produced from hardened polyurethane foam on the basis of data from contiguous computer tomography slices. In two patients, the models were used to plan correction osteotomies and resections, with the assistance of image-guided surgery in one of the patients. In four patients, the models were used to plan tumor resections and to produce custom-made spinal implants. RESULTS: In all the patients, the surgical procedure could be performed exactly according to the preplanned intervention. The polyurethane real-size models provided essential and additional information by direct visual and tactile feedback. They allowed in vitro testing of custom-made spinal implants with a perfect fit. CONCLUSIONS: Real-size spinal models made from polyurethane foam can be used to provide excellent understanding of the complex spinal pathology in highly selected patients. These models allow complex spinal surgery with a more predictable outcome.

Adolescent↗
PubMed2000

Electrical impedance tomography (EIT) in applications related to lung and ventilation: a review of experimental and clinical activities.

This review article is a summary of the publications dealing with the pulmonary applications of electrical impedance tomography (EIT). Original papers on EIT lung imaging published over 15 years are analysed and several aspects of the performed EIT measurements summarized. Information on the type of the EIT device and electrodes used, the studied transverse thoracic planes, the data acquisition rate, the number of studied animals, normal subjects or patients, the kind of lung pathology, the performed ventilatory manoeuvres and other interventions, as well as the applied reference techniques, is given. The type of the generated pulmonary EIT images and the quantitative analysis of the EIT data are described. Finally, the major results achieved are presented, followed by an analysis of the perspectives of EIT in clinical applications. A comparative analysis of the EIT hardware and the quality of the evaluation tools was not performed.

Animals↗
PubMed2006

High-level virtual reality simulator for endourologic procedures of lower urinary tract.

OBJECTIVES: To analyze the limitations of existing simulators for urologic techniques, and then test and evaluate a novel virtual reality (VR) simulator for endourologic procedures of the lower urinary tract. Surgical simulation using VR has the potential to have a tremendous impact on surgical training, testing, and certification. Endourologic procedures seem to be an ideal target for VR systems. METHODS: The URO-Trainer features genuine VR, obtained from digital video footage of more than 400 endourologic diagnostic and therapeutic procedures, as well as data from cross-sectional imaging. The software offers infinite random variations of the anatomy and pathologic features for diagnosis and surgical intervention. An advanced haptic force feedback is incorporated. Virtual cystoscopy and resection of bladder tumors were evaluated by 24 medical students and 12 residents at our department. RESULTS: The system was assessed by more than 150 international urologists with varying experience at different conventions and workshops from March 2003 to September 2004. Because of these evaluations and constant evolutions, the final version provides a genuine representation of endourologic procedures. Objective data are generated by a tutoring system that has documented evident teaching benefits for medical students and residents in cystoscopy and treatment of bladder tumors. CONCLUSIONS: The URO-Trainer represents the latest generation of endoscopy simulators. Authentic visual and haptic sensations, unlimited virtual cases, and an intelligent tutoring system make this modular system an important improvement in computer-based training and quality control in urology.

Computer Simulation↗