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Biomedical subjects

William W Mayo-Smith

Publications and source records attributed to William W Mayo-Smith.

At least 19 recordsLinked to original sources
PubMed2006

Percutaneous image-guided thermal ablation and radiation therapy: outcomes of combined treatment for 41 patients with inoperable stage I/II non-small-cell lung cancer.

PURPOSE: To evaluate the clinical outcomes in patients with early-stage non-small-cell lung cancer (NSCLC) after combined treatment with thermal ablation and radiation therapy (RT). MATERIALS AND METHODS: Forty-one patients with inoperable stage I/II NSCLC tumors underwent thermal ablation and RT at our institution between 1998 and 2005. Thirty-seven radiofrequency (RF) ablation procedures and four microwave ablation procedures were performed. Ablations were followed by standard-fraction external-beam RT within 90 days (n = 27) or postprocedural brachytherapy (n = 14). Survival and local recurrence were the primary endpoints evaluated by Kaplan-Meier analysis. RESULTS: The median follow-up was 19.5 months. The overall survival rates were 97.6% at 6 months, 86.8% at 1 year, 70.4% at 2 years, and 57.1% at 3 years. Patients with tumors smaller than 3 cm (n = 17) had an average survival time of 44.4 +/- 5.4 months (SE). Patients with tumors 3 cm or larger (n = 24) had an average survival time of 34.6 +/- 7.0 months (P = .08). Local recurrence occurred in 11.8% of tumors smaller than 3 cm after an average of 45.6 +/- 4.1 months and in 33.3% of the larger tumors after an average of 34.0 +/- 7.8 months (P = .03). Outcomes in the brachytherapy and RT groups did not differ significantly. Nine of 15 pneumothoraces required chest tube drainage (22.0%). CONCLUSIONS: Thermal ablation followed by RT for inoperable stage I/II NSCLC has a relatively low rate of complications that are easily managed. Combined therapy may result in an improved survival compared with either modality alone.

Aged↗
PubMed2006

Radiofrequency ablation followed by conventional radiotherapy for medically inoperable stage I non-small cell lung cancer.

PURPOSES: The standard treatment of stage I non-small cell lung cancer (NSCLC) is surgical resection. Some patients are poor surgical candidates due to severe comorbid medical conditions. Radiotherapy alone has historically been used in this patient population with limited success. Radiofrequency ablation (RFA) is an image-guided, thermally mediated ablative technique recently applied to lung tumors. Combination therapy with both these treatments has not been previously performed. We report our experience with combined CT-guided RFA and conventional radiotherapy in 24 medically inoperable patients with a minimum of 2-year study follow-up in surviving patients. PATIENTS AND METHODS: Twenty-four consecutive, medically inoperable patients with biopsy-proven, stage I NSCLC were treated with CT-guided RFA followed by radiotherapy to a dose of 66 Gy. RFA was performed with a single or cluster cool-tip F electrode; 21 patients were staged before therapy using fluorodeoxyglucose-positron emission tomography. RESULTS: There were 14 women and 10 men (median age, 76 years; range, 58 to 85 years). The histologic subtypes were squamous cell (n = 13), adenocarcinoma (n = 5), and undifferentiated (n = 6). All patients received RFA followed by three-dimensional conformal radiotherapy. There were no treatment-related deaths or grade 3/4 toxicities. Pneumothorax requiring chest tubes developed in three patients (12.5%). At a mean follow-up period of 26.7 months (range, 6 to 65 months), 14 patients (58.3%) died, with cumulative survival rates of 50% and 39% at the end of 2 years and 5 years, respectively. Ten of the deaths were cancer related. Two patients had local recurrence (8.3%), while nine patients had systemic metastatic disease. Three patients died of respiratory failure with no evidence of active disease, and one patient died of a cerebrovascular accident at 18-month follow-up. Pleural effusions developed after treatment in six patients (25%), which proved to be malignant in one patient. CONCLUSION: RFA followed by conventional radiotherapy is feasible in this population of medically inoperable stage I NSCLC patients. Procedural complication rates are low, and no additional major toxicities were seen despite the addition of RFA. Local control and survival rates appear to be better than with radiotherapy alone.

Adult↗
PubMed2005

Adnexal masses in pregnancy: surgery compared with observation.

OBJECTIVE: To estimate whether the delay of surgery impacts the risk of adverse maternal and fetal outcomes in patients diagnosed with an adnexal mass during pregnancy. METHODS: A review was performed of pregnant patients diagnosed with an adnexal mass 5 cm or greater in diameter. Data collected included age, gravity/parity, gestational age at diagnosis, and presenting symptoms. Ultrasound examinations were evaluated for mass size and complexity. Pregnancy outcome, complications, and surgical pathology were reviewed. RESULTS: Between 1990 and 2003, 127,177 deliveries were performed at our institution. An adnexal mass 5 cm in diameter or greater was diagnosed in 63 (0.05%) patients. Pathologic diagnosis was available for 59 (94%) patients. The remaining 4 patients were lost to follow-up and excluded from the analysis. Antepartum surgery was performed in 17 patients (29%): 13 because of ultrasound findings that suggested malignancy and 4 secondary to ovarian torsion. The remaining patients were observed, with surgery performed in the postpartum period or at time of cesarean delivery. The majority of masses were dermoid cysts (42%). Four patients were diagnosed with ovarian cancer (6.8% of masses, 0.0032% of deliveries), and one patient (1.7%) had a tumor of low malignant potential. Antepartum surgery due to ultrasound findings that caused concern was performed on all 5 women diagnosed with a malignancy or borderline tumor, compared with 12 (22%) of the patients with benign tumors (P < .01). CONCLUSION: In select cases, close observation is a reasonable alternative to antepartum surgery in patients with an adnexal mass during pregnancy.

Adnexal Diseases↗
PubMed2005

Microwave ablation: principles and applications.

Microwave ablation is the most recent development in the field of tumor ablation. The technique allows for flexible approaches to treatment, including percutaneous, laparoscopic, and open surgical access. With imaging guidance, the tumor is localized, and a thin (14.5-gauge) microwave antenna is placed directly into the tumor. A microwave generator emits an electromagnetic wave through the exposed, noninsulated portion of the antenna. Electromagnetic microwaves agitate water molecules in the surrounding tissue, producing friction and heat, thus inducing cellular death via coagulation necrosis. The main advantages of microwave technology, when compared with existing thermoablative technologies, include consistently higher intratumoral temperatures, larger tumor ablation volumes, faster ablation times, and an improved convection profile. Microwave ablation has promising potential in the treatment of primary and secondary liver disease, primary and secondary lung malignancies, renal and adrenal tumors, and bone metastases. The technology is still in its infancy, and future developments and clinical implementation will help improve the care of patients with cancer.

Adolescent↗
PubMed2005

Percutaneous cryoablation of symptomatic extraabdominal metastatic disease: preliminary results.

OBJECTIVE: The objective of our study was to describe our initial experience using percutaneous cryoablation for palliation of symptomatic extraabdominal metastases or recurrent soft-tissue tumors. CONCLUSION: Preliminary results suggest that percutaneous cryoablation may offer a minimally invasive alternative for relief of symptomatic metastatic disease in patients for whom conventional therapy failed.

Adult↗
PubMed2005

CT imaging findings of pulmonary neoplasms after treatment with radiofrequency ablation: results in 32 tumors.

OBJECTIVE: The purpose of this study is to describe the CT appearance of thoracic neoplasms after treatment with radiofrequency ablation (RFA). MATERIALS AND METHODS: Thirty-two thoracic neoplasms in 26 patients had pulmonary RFA and imaging follow-up. Fourteen neoplasms were primary lung cancer and 18 were metastases. The mean pretreatment neoplasm size was 3.1 cm (range, 1.0-7.0 cm), and the average number of neoplasms treated per patient was 1.2 (range, 1-3). The mean follow-up was 10.1 months (range, 1-30 months). Imaging findings on CT were evaluated by three radiologists and documented by consensus. RESULTS: The most common finding immediately after treatment was peripheral ground-glass opacity surrounding the treated neoplasm, seen in 27 of 32 tumors (84%). This rapidly resolved in all but one patient by the end of the first month. Cavitation was seen in 10 of 32 tumors (31%) on follow-up CT and was most common in neoplasms in the inner two thirds of the lung and adjacent to a segmental bronchus. Sixty percent of the cavitations decreased in size on follow-up scans. Ten of 32 tumors (31%) that did not develop cavitation developed bubble lucencies on follow-up CT. Pleural thickening was found in 12 of 22 (55%) parenchymal neoplasms, and linear opacifications were seen between the treated lesion and adjacent pleura in 14 of 22 parenchymal tumors (64%). Pleural effusions were seen in four patients (15%). Fourteen of 22 tumors (64%) with follow-up imaging at 1 month enlarged from pretreatment CT scans. At 3 and 6 months after RFA, the majority remained stable in size. CONCLUSION: Peripheral ground-glass opacity, cavitation, bubble lucencies, and pleural changes are common findings on CT after RFA. Many treated neoplasms increase in size from baseline on 1- to 3-month follow-up CT scans and then remain stable thereafter. Enlargement of a treated tumor after 6 months is felt to represent local recurrence. Stability of a treated lesion beyond 6 months does not guarantee continued stability.

Aged↗
PubMed2005

Characterization of breast masses with sonography: can biopsy of some solid masses be deferred?

OBJECTIVE: To determine whether sonography can be used to categorize some solid breast masses as probably benign so that biopsy can be deferred. METHODS: We prospectively characterized 844 sonographically visible solid breast masses referred for biopsy. Mammographic and sonographic features of the masses were recorded, and all masses were categorized by American College of Radiology Breast Imaging Reporting and Data System classification before biopsy. Of the 844 masses, 148 were categorized as probably benign (Breast Imaging Reporting and Data System category 3). Sonographically guided biopsy (n = 804) or fine-needle aspiration (n = 40) was performed for pathologic correlation. RESULTS: Of the 148 masses that met the sonographic criteria for probably benign masses, there was 1 malignancy, for a negative predictive value of 99.3%. CONCLUSIONS: Follow-up can be an acceptable alternative to biopsy for sonographically probably benign solid masses.

Adolescent↗
PubMed2004

Adrenal neoplasms: CT-guided radiofrequency ablation--preliminary results.

PURPOSE: To evaluate initial experience with radiofrequency (RF) ablation of adrenal neoplasms. MATERIALS AND METHODS: Thirteen adrenal masses in 12 patients (bilateral metastases in one patient) were treated with computed tomography (CT)-guided percutaneous RF ablation. Eleven adrenal lesions were metastases (five from lung cancer, four from renal cell carcinoma, and two from melanoma); one lesion was a pheochromocytoma and one was an aldosteronoma. There were 10 men and two women (average age, 58 years; range, 40-77 years) in the study; average adrenal mass diameter was 3.9 cm (range, 1-8 cm). Average number of RF applications per adrenal mass was 2.7 (range, 1-5 applications); average time per application was 7.8 minutes (range, 4-13 minutes). An internally cooled single electrode was used in five sessions; an internally cooled cluster electrode was used in eight sessions. RESULTS: Average follow-up was 11.2 months (range, 1-46 months). Eleven of 13 lesions were treated successfully with RF ablation after one session. Successful treatment was defined as lack of enhancement of the treated region on follow-up CT images and resolution of the biochemical abnormality in two patients. In two patients with large adrenal lesions (4 and 8 cm in diameter), enhancement of residual tissue was observed after one treatment session; this finding was indicative of residual tumor. One patient with thrombocytopenia that resulted from chemotherapy had a small hematoma, but no transfusion was required. No patient developed hypertension during the RF application. No patient with metastases had recurrent tumor at the treated site, and this lack of recurrence indicated effective local control; 11 patients had progression of metastatic disease at extraadrenal sites. CONCLUSION: Preliminary data suggest that CT-guided RF ablation is an effective technique for local control of adrenal neoplasms.

Adrenal Gland Neoplasms↗
PubMed2004

CT pulmonary angiography: quantification of pulmonary embolus as a predictor of patient outcome--initial experience.

PURPOSE: To determine whether quantification of pulmonary embolus (PE) with computed tomographic (CT) pulmonary angiography by using a standardized index is a predictor of patient outcome. MATERIALS AND METHODS: Multi-detector row CT was performed in 59 hospitalized patients (mean age, 61 years; age range, 22-89 years). PE was identified retrospectively by two radiologists who were blinded to patient outcome. A pulmonary arterial obstruction index was derived for each set of images on the basis of embolus size and location. By using logistic regression, PE indexes were compared with patient outcome-survival or death-to determine if there was a correlation between PE volume and survival. RESULTS: The PE index is a significant predictor of patient outcome (P =.002). One of 53 patients (1.9%) with an index of less than 60% died. Cause of death was end-stage malignancy. Five of six patients (83%) with an index of 60% and higher died. All five deaths were related to the presence of PE. The one survivor with a PE index higher than 60% received thrombolytic therapy. By using a cutoff of 60%, the PE index was used to identify 52 of 53 (98%) patients who survived and five of six (83%) patients who died. CONCLUSION: Preliminary evidence suggests that quantification of clot with CT pulmonary angiography is an important predictor of patient death in the setting of PE.

Adult↗
PubMed2003

Detection of intracranial aneurysms: multi-detector row CT angiography compared with DSA.

PURPOSE: To prospectively compare the effectiveness of multi-detector row computed tomographic (CT) angiography with that of conventional intraarterial digital subtraction angiography (DSA) used to detect intracranial aneurysms in patients with nontraumatic acute subarachnoid hemorrhage. MATERIALS AND METHODS: Thirty-five consecutive adult patients with acute subarachnoid hemorrhage were recruited into the institutional review board-approved study and gave informed consent. All patients underwent both multi-detector row CT angiography and DSA no more than 12 hours apart. CT angiography was performed with a multi-detector row scanner (four detector rows) by using collimation of 1.25 mm and pitch of 3. Images were interpreted at computer workstations in a blinded fashion. Two radiologists independently reviewed the CT images, and two other radiologists independently reviewed the DSA images. The presence and location of aneurysms were rated on a five-point scale for certainty. Sensitivity and specificity were calculated independently for image interpretation performed by the two CT image readers and the second DSA image reader by using the first DSA reader's interpretation as the reference standard. RESULTS: A total of 26 aneurysms were detected at DSA in 21 patients, and no aneurysms were detected in 14 patients. Sensitivity and specificity for CT angiography were, respectively, 90% and 93% for reader 1 and 81% and 93% for reader 2. The mean diameter of aneurysms detected on CT angiographic images was 4.4 mm, and the smallest aneurysm detected was 2.2 mm in diameter. Aneurysms that were missed at initial interpretation of CT angiographic images were identified at retrospective reading. CONCLUSION: Multi-detector row CT angiography has high sensitivity and specificity for detection of intracranial aneurysms, including small aneurysms, in patients with nontraumatic acute subarachnoid hemorrhage.

Acute Disease↗
PubMed2003

Portal venous gas detected by computed tomography: is surgery imperative?

BACKGROUND: Portal vein gas (PVG) has historically been associated with mortality rates of 75% or higher and mandatory abdominal exploration. The following study reassesses the clinical significance of gas in the portal venous system detected by computed tomography (CT) and reevaluates the need for surgical intervention in that setting. METHODS: We performed a retrospective chart review of 26 patients presenting with gas in the portal venous system as imaged by CT between August 1, 1993 and April 8, 2001. Characteristics assessed included age, sex, clinical presentation and course, additional CT findings, diagnosis, surgical versus non-surgical management, surgical findings, pathologic correlation, and mortality. RESULTS: Of the 26 patients who had gas in the portal venous system by CT, 11 underwent surgery to determine underlying pathology. Of those who underwent surgery, 8 survived to be discharged while 3 died (73% surgical survival). The survivors presented with gastrointestinal related signs/symptoms and were found at the time of surgery to have adhesions, non-surgically treated inflammation, unclear pathology, or resectable lesions. Those who died all demonstrated marked bowel ischemia intraoperatively. Among patients who did not undergo surgery, 9 survived and 6 died (60% nonsurgical survival). Those who survived presented either asymptomatically or with pathology including acute pancreatitis, recent hypotensive episode, uncomplicated diverticulitis, unresectable colon cancer, or infectious etiology. Those who died were poor surgical candidates or status postvascular procedure. The overall survival in patients with portal venous gas by CT was 65%. CONCLUSION: Portal venous gas on CT is associated with a wide range of pathologies that do not necessarily warrant surgical management. Clinical presentation should be correlated with the presence of PVG and other associated CT findings prior to deciding whether surgery should be performed.

Adult↗
PubMed2003

Transportable versus fixed platform CT scanners: comparison of costs.

PURPOSE: To compare the aggregate hospital technical costs of a transportable computed tomographic (CT) scanner used to image patients in an intensive care unit with those of a fixed platform CT scanner in the radiology department. MATERIALS AND METHODS: Direct fixed costs (ie, machine and service contract costs) and direct variable costs (ie, personnel costs) were calculated. Indirect costs, including space costs and departmental overhead, were calculated. Total costs were calculated as the sum of indirect, direct fixed, and direct variable costs. Personnel costs were calculated from time-motion analyses involving 95 patients who underwent brain CT with either a transportable (n = 51) or a fixed platform (n = 44) CT scanner. Costs per examination were calculated by using both low- and high-examination-volume models and compared with use of the Wilcoxon rank sum test. RESULTS: The total cost per examination for the transportable scanner ranged from 108.98 dollars to 167.20 dollars for the high- and low-volume models. Total cost per examination for the fixed platform scanner ranged from 75.24 dollars to 112.39 dollars for the high- and low-volume models. For the transportable scanner, direct fixed, variable, and overhead costs were 87.05 dollars, 70.73 dollars, and 9.42 dollars per examination, respectively, with the low-volume model. The corresponding costs for the fixed platform scanner were 46.66 dollars, 55.69 dollars, and 10.04 dollars, respectively. CONCLUSION: The technical cost of using an in-hospital transportable CT scanner is higher than that of using a fixed platform scanner.

Costs and Cost Analysis↗
PubMed2003

Imaging-guided percutaneous radiofrequency ablation of solid renal masses: techniques and outcomes of 38 treatment sessions in 32 consecutive patients.

OBJECTIVE: The purpose of this study was to describe the treatment techniques and results of 38 consecutive imaging-guided percutaneous radiofrequency ablations of solid renal masses performed in 32 patients. MATERIALS AND METHODS: Solid renal masses in 32 patients underwent 38 treatment sessions using imaging-guided percutaneous radiofrequency ablation. During 36 sessions, radiofrequency ablation was performed using CT guidance, and two, using sonographic guidance. The average patient age was 76 years (range, 52-87 years), and the average renal mass size was 2.6 cm (range, 1-5 cm). The average number of radiofrequency treatments per solid mass at each session was 2.4 (range, 1-6 treatments), and the average time per treatment was 9.2 min (range, 3-14 min). A single electrode was used in 12 sessions, and a cluster electrode was used in 26 sessions. The average follow-up time was 9 months (range, 1-36 months). RESULTS: Twenty-six of 32 patients had successful treatment of the solid renal mass using percutaneous imaging-guided radiofrequency ablation after one treatment session. Successful treatment was defined as lack of enhancement of the treated region on follow-up CT. Six of 32 patients had residual enhancing tissue after the first treatment session and returned for a second session. Five of these six retreatments were successful. Masses requiring a second treatment session were significantly larger than masses treated in a single session (3.5 vs 2.4 cm, respectively; p = 0.0013). Two patients had perinephric hematomas (which did not require transfusion), and one patient developed a 5-mm skin metastasis at the electrode insertion site, which was resected without recurrence. CONCLUSION: Percutaneous imaging-guided radiofrequency ablation shows promise in the treatment of solid renal malignancies.

Adenoma, Oxyphilic↗
PubMed2003

Multiinstitutional computer database for recording nonvascular imaging-guided interventions.

OBJECTIVE: We sought to describe a multiinstitutional database created for tracking CT and sonographically guided interventional procedures. CONCLUSION: The database, created using commercially available software, has been placed on the secure hospital internal network for easy access from two institutions. More than 1,000 separate interventions have been added. The data may be queried and filtered for quality assurance and research purposes.

Computer Systems↗
PubMed2003

Intracanalicular aneurysm of the anterior inferior cerebellar artery revealed by multi-detector CT angiography.

A 62-year-old woman had sudden-onset headache and posterior neck pain, and a subarachnoid hemorrhage was revealed by unenhanced CT. Both multi-detector CT angiography and digital subtraction angiography were performed and revealed a small intracanalicular aneurysm of the left anterior inferior cerebellar artery. The patient underwent successful retrosigmoid craniectomy and trapping of the aneurysm. This case shows the ability of multi-detector CT angiography to indicate bony landmarks that can alter the surgical approach.

Angiography, Digital Subtraction↗
PubMed2002

Hepatic radiofrequency ablation.

HYPOTHESIS: Hepatic radiofrequency ablation (RFA) is effective in treating patients with unresectable hepatic malignancies. DESIGN: Case series of 123 patients with unresectable hepatic tumors or tumors with histological findings not traditionally treated by means of hepatic resection were considered for hepatic RFA. Median follow-up was 20 months. SETTING: Tertiary referral center. PATIENTS: The 123 patents underwent 168 RFA sessions from January 1, 1998, through September 30, 2001. Sixty-nine patients were male and 54, female; average age was 65 years (range, 1-89 years). Fifty-two patients had metastatic colorectal cancer; 30, hepatocellular carcinoma; and 41, cancers with other histological findings. INTERVENTIONS: A 200-W, cooled-tip RF probe system was used for all cases. Probe placement and ablation were monitored by means of real-time ultrasonography or fluoroscopic computed tomography. Final tissue temperature of greater than 50 degrees C was achieved in all cases. RESULTS: Initial treatment sessions were percutaneous in 87 patients, open operations in 33, and laparoscopic in 3. Repeated sessions were percutaneous in all but 2 patients. The mean number of lesions treated per session was 2.7 (range, 1-24). Mean tumor size was 5.2 cm (range, 0.5-15.0 cm). One death occurred within 30 days of a procedure. No hepatic bleeds, bile leaks, or adult respiratory distress syndrome occurred. Overall morbidity was 7.1%. Complications included hepatic abscesses in 4 patients, transient liver insufficiency in 3, segmental hepatic infarcts in 2, diaphragm paralysis in 1, hepatic artery-to-portal vein fistula in 1, and systemic hemolysis in 1. CONCLUSIONS: Hepatic RFA is an effective treatment option for patients with unresectable hepatic malignancies. Careful patient selection based on tumor size, location, and number and on patient clinical status should determine the choice of treatment. Further controlled trials are needed to determine the effect of hepatic RFA on long-term survival.

Adolescent↗
PubMed2002

Clinical applications of radio-frequency tumor ablation in the thorax.

Minimally invasive alternatives to surgery for the treatment of malignancy are becoming more attractive owing to improvements in technology, reduced morbidity and mortality, and the ability to provide treatment in an outpatient setting. Radio-frequency (RF) ablation has become the imaging-guided ablative method of choice because of its relatively low cost, its capability of creating large regions of coagulative necrosis in a controlled fashion, and its relatively low toxicity. RF ablation in the thorax involves the use of computed tomography (CT) to localize the tumor and determine the optimal approach. The size of the tumor determines whether a cluster of electrodes or a single electrode of a particular length will be used to perform the ablation. CT fluoroscopy aids in guiding placement of the electrode. In patients with non-small cell lung malignancy who are not candidates for surgery owing to poor cardiorespiratory reserve, RF ablation alone or followed by conventional radiation therapy with or without chemotherapy may prove to be a treatment option. In patients with metastatic disease, RF ablation may be suitable for treatment of a small tumor burden or for palliation of larger tumors that cause symptoms such as cough, hemoptysis, or pain. Patients with chest wall or osseous metastatic tumors in whom other therapies have failed may benefit from RF ablation as an alternative to radiation therapy.

Catheter Ablation↗