Payload for Contact Inspection Tasks with UAV Systems.

This paper presents a payload designed to perform semi-autonomous contact inspection tasks without any type of positioning system external to the UAV, such as a global navigation satellite system (GNSS) or motion capture system, making possible inspection in challenging GNSS- denied sites. This payload includes two LiDAR sensors which measure the distance between the UAV and the target structure and their inner orientation angle. The system uses this information to control the approaching of the UAV to the structure and the contact between both, actuating over the pitch and yaw signals. This control is performed using a hybrid automaton with different states that represent all the possible UAV status during the inspection tasks. It uses different control strategies in each state. An ultrasonic gauge has been used as the inspection sensor of the payload to measure the thickness of a metallic sheet. The sensor requires a stable contact in order to collect reliable measurements. Several tests have been performed on the system, reaching accurate results which show it is able to maintain a stable contact with the target structure.

New discretization method applied to NBV problem: Semioctree.

This paper presents a discretization methodology applied to the NBV (Next Best View) problem, which consists of determining the heuristical best position of the next scan. This new methodology is a hybrid process between a homogenous voxelization and an octree structure that preserves the advantages of both methods. An octree structure is not directly applicable to the NBV problem: as the point cloud grows with every successive scanning, the limits and position of the discretization, octree structure must coincide, in order to transfer the information from one scan to the next. This problem is solved by applying a first coarse voxelization, followed by the division of each voxel in an octree structure. In addition, a previous methodology for solving the NBV problem has been adapted to make use of this novel approach. Results show that the new method is three times faster than the homogenous voxelization for a maximum resolution of 0.2m. For this target resolution of 0.2m, the number of voxels/octants in the discretization is reduced approximately by a 400%, from 35.360 to 8.937 for the study case presented.

Four-year patency of PTFE grafts after replacement of the superior vena cava and the innominate veins.

We describe a simpler alternative to treating vena cava syndrome with composite spiral vein grafts. Instead, we used 2 polytetrafluoroethylene (PTFE) grafts to replace the resected superior vena cava and innominate veins of a man with a malignant thymoma. Both grafts have remained patent more than 4 years after surgery, and the patient has continued asymptomatic and free of malignancy. Therefore, we recommend using PTFE grafts to replace the great veins of the thorax.

Percutaneous needle biopsy of the irradiated skeleton.

Percutaneous needle biopsy was performed in 20 patients who had radiologic abnormalities after irradiation of the skeleton. The biopsies were performed to determine the nature of the bone changes and to differentiate radiation necrosis from metastases or local tumor extension. Eleven patients had tumors, two of which were radiation-induced sarcomas; nine patients did not show evidence of tumor. One patient had osteomyelitis rather than the suspected tumor. The value of percutaneous needle biopsy in the postirradiated skeleton is discussed.

Intraarterial cis-platinum chemotherapy for patients with primary and metastatic brain tumors.

A total of 49 patients were treated using intraarterial cis-platinum infusions at a dose of 100 mg/m2. The patients were separated into three groups. There were 13 patients with metastatic tumors, 10 with recurrent malignant gliomas, and 22 patients with high-grade gliomas who received intraarterial cis-platinum as part of an adjuvant program. In addition, four nongliomatous primary brain tumors were treated in this fashion. Cis-platinum was filtered immediately prior to intraarterial infusion using a 0.22-micron filter. Response to treatment was evaluated by follow-up CAT scans and neurologic examinations. There were three complete and eight partial responses in metastatic tumors, and eight partial responses in recurrent gliomas. The median survival was 19 weeks for patients with metastatic disease, and 16 weeks for patients with recurrent gliomas. Those high-grade glioma patients who received intraarterial cis-platinum as adjuvant chemotherapy along with CCNU and radiation therapy had a projected median survival of 91+ weeks. Toxicity from intraarterial cis-platinum following drug filtration was markedly reduced when compared with previous reports. Only five patients experiencing visual or central nervous system toxicity utilizing filtered cis-platinum and no radiographic or histopathologic evidence of central nervous system toxicity was observed. Bilateral deafness was observed following vertebral artery infusion in both patients treated in this manner and thus vertebral artery infusions should be avoided. Systemic toxicity was mild. Intracarotid infusion is a safe, well-tolerated delivery system for filtered cis-platinum with a high response rate for patients with both metastatic and primary malignant brain tumors.

Purely lytic osteosarcoma.

The radiographic features of 42 purely lytic osteosarcomas are presented. Purely lytic osteosarcoma is identified as a lytic lesion of bone with no demonstrable osteoid matrix by conventional radiographic modalities. Purely lytic osteosarcoma represented 13.7% of a group of 305 osteosarcomas. The most common presentation was that of a lytic ill-defined lesion with a moderate to large extraosseous mass component. Nine lesions presented with benign radiographic features. The differential diagnosis is outlined. The need for awareness of this type of presentation of osteosarcoma is stressed.

Periosteal chondroma: a radiographic spectrum.

The radiographic features of 22 cases of histologically proven periosteal chondroma are analyzed in detail. The typical tumor consisted in an area of outer cortex remodeling (scalloping) involving the metaphyseal lesion of a long bone with slightly overhanging edges and a small amount of cartilage calcified matrix adjacent to the scalloping. The presence of a visible soft tissue mass was uncommon, present in only third of the cases. The radiographic differential diagnosis is analyzed in detail and illustrated.

Computed tomography in liposarcoma.

Seventeen cases with proven liposarcoma were evaluated by computed tomography (CT) to assess the specificity and value of this radiographic modality. A specific diagnosis of liposarcoma could be made in only four cases (22%). Despite its relative nonspecificity, CT proved extremely useful in the clinical evaluation of this tumor and evidenced considerable superiority to other radiographic methods. In several cases, CT was the only radiographic modality to demonstrate the presence of the lesion. The use of CT gained additional important information in approximately 50% of the cases studied.

Diagnosis of eosinophilic granuloma of bone by cytology, histology, and electron microscopy of transcutaneous bone-aspiration biopsy.

The cytological, histological, and ultrastructural morphology of transcutaneous bone aspirates from five patients with eosinophilic granuloma of bone were studied. Use of this combined approach enabled us to make a definitive diagnosis of eosinophilic granuloma from a small quantity of tissue without having to resort to open biopsy. By light microscopy, eosinophilic granuloma is composed of a polymorphous infiltrate of characteristic lobulated histiocytes, eosinophils, polymorphonuclear leukocytes, and giant cells. Each specimen examined ultrastructurally demonstrated the characteristic Langerhans granule-containing histiocyte. Eosinophilic granuloma is a benign lesion which is readily diagnosed by this technique, and more aggressive diagnostic procedures usually are not warranted.

Computed tomography in the evaluation of small round cell tumors of bone.

The value of computed tomography (CT) in the management of 20 cases of round cell tumors of bone is reported. CT is useful in: (a) early diagnosis, particularly incomplex anatomical areas; (b) the evaluation of the extent of disease; (c) the determination of the radiation portals; (d) the evaluation of the response to therapy; and (e) the preoperative evaluation of those tumors removed surgically. In comparison with other radiographic modalities, CT was equally accurate in six and more accurate in 10 patients. In three cases CT alone revealed the presence of pathology.

Synovial hyperemia in giant cell tumor of bone: angiographic pitfall.

Arteriography has been found useful in the clinical staging of giant cell tumors of bone in its capacity to demonstrate the presence and extent of soft tissue, extraosseous extension of the tumor. A potential source of error is the presence of hyperemic synovial tissue that may closely resemble tumor vascularity, and therefore be confused with tumor extraosseous extension. Of the 48 giant cell tumors in this series, 21 demonstrated extraosseous vascularity representing synovial hyperemia. Two patients were considered to have extraosseous tumor extent but only hypertrophic synovial tissue was found at surgery. The angiographic features of synovial hyperemia are outlined.

Computed tomography in the evaluation of osteosarcoma: experience with 25 cases.

Experience with computed tomography (CT) in 25 patients with histologically proven osteosarcoma is presented. CT was as accurate as conventional radiographic methods in determining the presence of a lesion, but it was definitely superior in defining the extent of disease, particularly intramedullary extension and soft tissue extraosseous tumor component. CT was capable of demonstrating skip metastases in one patient. CT plays a key role in the preoperative evaluation of osteosarcoma patients, particularly when less than radical surgery is planned as primary treatment and when postoperative recurrence is suspected. CT is also useful in assessing the response to therapy in nonsurgical cases. The technique involved in the performance of this examination is discussed.

Angiography in giant-cell bone tumors.

Angiography was performed on 48 patients with giant-cell bone tumors. Sixty-four per cent were hypervascular; 25% were hypo- or moderately vascular; and 10% were avascular. Findings were similar in the 45 benign and 3 malignant tumors. There was no correlation between the findings and degree of histological aggressiveness. There was a high (60%) incidence of aneurysmal bone cyst component in the hypovascular group. Hyperemic synovium, occasionally simulating tumor, was seen in 80% of surgically proved lesions. Angiography was useful in assessing tumor extent, particularly when an extraosseous component was present.

The value of percutaneous needle biopsy in the management of primary bone tumors.

Thirty-four suspected primary bone neoplasms were evaluated by needle biopsy at M. D. Anderson Hospital and Tumor Institute between September 1976 and February 1978. Adequate material for evaluation was obtained in 31 cases. The accuracy rate of the procedure was 93%. Needle biopsy is a rapid, effective and safe method of evaluating unsuspected primary lesions of bone. The indications, contraindications, and technique are emphasized. The benefits over open biopsy are indicated.

Metastatic osteogenic sarcoma to the brain.

The radiographic appearances of intracranial metastases from primary osteogenic sarcomas in three patients are presented. In two patients, the diagnosis of metastatic disease could be made on conventional roentgenograms of the skull since mineralization of tumor osteoid could be seen within the brain parenchyma. This had a similar appearance to the primary bone tumor. Angiography in two of the three patients revealed the cerebral metastases to be hypervascular with tumor vessels, tumor stain and early draining veins.

Arterial occlusion of pelvic bone tumors.

Arterial occlusion of the internal iliac artery was successful in the relief of pain due to primary and secondary neoplasms of the bony pelvis in 8 of 9 patients. These included 3 giant cell tumors, 1 aneurysmal bone cyst, 1 recurrent chondrosarcoma, 3 metastatic renal cell carcinoma and 1 metastatic clear cell sarcoma. Calcification of the margin of the lesion occurred in 3 of 4 primary neoplasms after infarction. The transcatheter arterial occlusion was accomplished utilizing Gelfoam and stainless steel coils. Although most patients experienced pain and fever for several days following the procedure, no permanent sequelae or complications were encountered.

Computed tomography in the evaluation of post-nephrectomy patients.

Twenty-one CT examinations were performed in 19 patients who had undergone previous nephrectomy for renal carcinoma or retroperitoneal malignancy. Nine patients were free of disease and 10 had recurrence. Findings of recurrent disease included masses in the vacant renal fossa, inability to visualize the inferior vena cava or aorta, and ipsilateral psoas muscle thickening. Possible pitfalls in diagnosis are discussed.

Osteogenic sarcoma after the age of 50: a radiographic evaluation.

Twenty-four cases of primary osteosarcoma in individuals over the age of 50 are described. This represents 6% of all osteosarcomas and 80% of osteosarcomas occurring over the age of 50 at this institution. Radiographically, features were similar to osteosarcoma in younger individuals. Females were more frequently affected than males (2.4:1). The radiographic features are discussed in detail, and the differential diagnosis outlined.

Computed tomography in the evaluation of musculoskeletal neoplasms.

In a study of 62 musculoskeletal neoplasms, computed tomography contributed little to establishing tissue diagnosis. Its primary value lay in the assessment of intraosseous and/or extraosseous extent of disease. CT also established the presence or absence of disease in a small number of cases with clinically questionable findings. In most cases, conventional radiographic methods were superior in diagnosing musculoskeletal neoplasms.