Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Timothy J. Welch is active.

Publication


Featured researches published by Timothy J. Welch.


Journal of Clinical Oncology | 2004

Percutaneous Image-Guided Radiofrequency Ablation of Painful Metastases Involving Bone: A Multicenter Study

Matthew P. Goetz; Matthew R. Callstrom; J. William Charboneau; Michael A. Farrell; Timothy P. Mans; Timothy J. Welch; Gilbert Y. Wong; Jeff A. Sloan; Paul J. Novotny; Ivy A. Petersen; Robert A. Beres; Daniele Regge; Rodolfo Capanna; Mark B. Saker; Dietrich H. W. Grönemeyer; Athour Gevargez; Kamran Ahrar; Michael A. Choti; Thierry J. Debaere; Joseph Rubin

PURPOSE Few options are available for pain relief in patients with bone metastases who fail standard treatments. We sought to determine the benefit of radiofrequency ablation (RFA) in providing pain relief for patients with refractory pain secondary to metastases involving bone. PATIENTS AND METHODS Thirty-one US and 12 European patients with painful osteolytic metastases involving bone were treated with image-guided RFA using a multitip needle. Treated patients had > or = 4/10 pain and had either failed or were poor candidates for standard treatments such as radiation or opioid analgesics. Using the Brief Pain Inventory-Short Form, worst pain intensity was the primary end point, with a 2-unit drop considered clinically significant. RESULTS Forty-three patients were treated (median follow-up, 16 weeks). Before RFA, the mean score for worst pain was 7.9 (range, 4/10 to 10/10). Four, 12, and 24 weeks following treatment, worst pain decreased to 4.5 (P <.0001), 3.0 (P <.0001), and 1.4 (P =.0005), respectively. Ninety-five percent (41 of 43 patients) experienced a decrease in pain that was considered clinically significant. Opioid usage significantly decreased at weeks 8 and 12. Adverse events were seen in 3 patients and included (1) a second-degree skin burn at the grounding pad site, (2) transient bowel and bladder incontinence following treatment of a metastasis involving the sacrum, and (3) a fracture of the acetabulum following RFA of an acetabular lesion. CONCLUSION RFA of painful osteolytic metastases provides significant pain relief for cancer patients who have failed standard treatments.


Gastroenterology | 2003

Prospective blinded evaluation of computed tomographic colonography for screen detection of colorectal polyps.

C. Daniel Johnson; William S. Harmsen; Lynn A. Wilson; Robert L. MacCarty; Timothy J. Welch; Duane M. Ilstrup; David A. Ahlquist

BACKGROUND & AIMS This study used a low lesion prevalence population reflective of the screening setting to estimate the sensitivity and specificity of computerized tomographic (CT) colonography for detection of colorectal polyps. METHODS This prospective, blinded study comprised 703 asymptomatic persons at higher-than-average risk for colorectal cancer who underwent CT colonography followed by same-day colonoscopy. Two of 3 experienced readers interpreted each CT colonography examination. RESULTS Overall lesion prevalence for adenomas >/=1 cm in diameter was 5%. Seventy percent of all lesions were proximal to the descending colon. With colonoscopy serving as the gold standard, CT colonography detected 34%, 32%, 73%, and 63% of the 59 polyps >/=1 cm for readers 1, 2, 3, and double-reading, respectively; and 35%, 29%, 57%, and 54% of the 94 polyps 5-9 mm for readers 1, 2, 3, and double-reading, respectively. Specificity for CT colonography ranged from 95% to 98% and 86% to 95% for >1 cm and 5-9-mm polyps, respectively. Interobserver variability was high for CT colonography with kappa statistic values ranging from -0.67 to 0.89. CONCLUSIONS In a low prevalence setting, polyp detection rates at CT colonography are well below those at colonoscopy. These rates are less than previous reports based largely on high lesion prevalence cohorts. High interobserver variability warrants further investigation but may be due to the low prevalence of polyps in this cohort and the high impact on total sensitivity of each missed polyp. Specificity, based on large numbers, is high and exhibits excellent agreement among observers.


Skeletal Radiology | 2006

Image-guided ablation of painful metastatic bone tumors: a new and effective approach to a difficult problem.

Matthew R. Callstrom; J. William Charboneau; Matthew P. Goetz; Joseph Rubin; Thomas D. Atwell; Michael A. Farrell; Timothy J. Welch; Timothy P. Maus

Painful skeletal metastases are a common problem in cancer patients. Although external beam radiation therapy is the current standard of care for cancer patients who present with localized bone pain, 20–30% of patients treated with this modality do not experience pain relief, and few further options exist for these patients. For many patients with painful metastatic skeletal disease, analgesics remain the only alternative treatment option. Recently, image-guided percutaneous methods of tumor destruction have proven effective for treatment of this difficult problem. This review describes the application, limitations, and effectiveness of percutaneous ablative methods including ethanol, methyl methacrylate, laser-induced interstitial thermotherapy (LITT), cryoablation, and percutaneous radiofrequency ablation (RFA) for palliation of painful skeletal metastases.


Abdominal Imaging | 2002

Detection of flat lesions in the colon with CT colonography

Jeff L. Fidler; C. D. Johnson; Robert L. MacCarty; Timothy J. Welch; Amy K. Hara; William S. Harmsen

AbstractBackground:We investigated whether flat lesions of the colon could be detected on computed tomographic colonography (CTC). Methods: CTC and conventional colonoscopy were performed on 547 consecutive patients. A subset of 22 polyps was described as flat on colonoscopy (n= 16) or CTC (n= 6) and are the basis of this report. CTC was performed with a standard technique (5-mm collimation, 3-mm reconstruction intervals). Patients were scanned in supine and prone positions. Examinations were randomly assigned and reviewed in a blinded fashion by two of three radiologists. Prospective interpretations were recorded. All patients had conventional colonoscopy, which served as the gold standard. Results: Twenty-two flat lesions ranging from 0.4 to 3.5 cm were histologically classified as adenomatous (n= 8) or hyperplastic (n= 14). The sensitivities for detecting all flat lesions and flat adenomas by each reviewer were 43% and 100%, 65% and 100%, and 15% and 13%, respectively. “Double reading” resulted in detection of 68% of all lesions and 100% of adenomas. Of the seven hyperplastic polyps missed by both reviewers, four were identified retrospectively. Conclusion: Flat lesions of the colon represent an important source of false negative CTC examinations. Awareness of their morphology can assist radiologists in finding most of these challenging lesions.


Mayo Clinic Proceedings | 2000

Renal Cell Carcinoma Metastatic to the Pancreas: Clinical and Radiological Features

Reza Ghavamian; Katherine A. Klein; David H. Stephens; Timothy J. Welch; Andrew J. LeRoy; Ronald L. Richardson; Patrick A. Burch; Horst Zincke

OBJECTIVE To review the clinical features, computed tomographic (CT) appearance, and treatment outcomes in a case series of patients with renal cell carcinoma (RCC) metastatic to the pancreas. PATIENTS AND METHODS We retrospectively reviewed the records of 23 patients (15 men and 8 women) with RCC metastatic to the pancreas, detected by CT examination between 1986 and 1996. All patients had undergone a previous nephrectomy for RCC. RESULTS Isolated mild elevation in liver function test results (in 5 patients) or in serum amylase level (in 8 patients) was observed. New-onset diabetes was detected in 3 patients. The CT characteristics of the pancreatic metastases generally resembled those of primary RCC with well-defined margins and greater enhancement than normal pancreas with a central area of low attenuation. The mean interval between resection of the primary RCC and detection of the pancreatic metastases was 116 months (range, 1-295 months). In 18 patients (78%), the pancreatic metastases were diagnosed more than 5 years after nephrectomy. The pancreas was the initial metastatic site in 12 patients (52%). Survival was shortened with higher tumor grade (mean survival time of 41 months and 10 months in patients with grade 2 and 3, respectively). Surgical resection was carried out in 11 patients (7 distal and 3 total pancreatectomies and 1 distal pancreatectomy followed 4 years later by total pancreatectomy), with 8 patients alive at a mean follow-up of 4 years, 6 of whom remained free of recurrence. Overall, 12 patients (52%) were alive at a mean of 42 months after diagnosis of metastatic disease. CONCLUSIONS The appearance of metastatic RCC lesions in the pancreas closely resembles the appearance of primary RCC on CT images. Pancreatic metastases from RCC are frequently detected many years after nephrectomy. Patient survival correlates with tumor grade. Histologic analysis of pancreatic masses in patients with a history of resected primary RCC is important since the prognosis for RCC metastatic to the pancreas is much better than that for primary pancreatic adenocarcinoma.


Surgical Clinics of North America | 1988

Hemorrhage in major pelvic fractures.

Peter Mucha; Timothy J. Welch

Significant hemorrhage following major pelvic fractures should always be expected. Early recognition of such fractures during the resuscitation of any multiply injured patient is essential before instituting measures that might combat blood loss. In the majority of patients, simple resuscitative measures, including employment of the pneumatic antishock garment, will suffice. With certain types of fracture geography, the early application of external fixation devices may also play an important role. Increasingly popular has been the technique of diagnostic angiography and therapeutic embolization, applicable to approximately 3 per cent of all pelvic fracture patients. With exsanguinating hemorrhage, even the best equipped and most sophisticated major trauma centers can be taxed. The decision whether a patient should be taken directly to the operating room or to the angiography suite remains one of the most difficult for even the most highly skilled trauma surgeon. Patients with rapidly expanding or free rupture of pelvic hematomas noted at the time of celiotomy, or those with large open wounds, usually leave no recourse but to attempt direct operative control, to include even the most morbid option of a life-saving hemipelvectomy or corpectomy. More often, however, once other sources of surgically correctable hemorrhage are controlled or ruled out, diagnostic angiography followed by therapeutic embolization is a mainstay in the modern-day management of pelvic fracture hemorrhage.


American Journal of Roentgenology | 2010

Incidence of Bleeding After 15,181 Percutaneous Biopsies and the Role of Aspirin

Thomas D. Atwell; Ryan L. Smith; Gina K. Hesley; Matthew R. Callstrom; Cathy D. Schleck; W. Scott Harmsen; J. William Charboneau; Timothy J. Welch

OBJECTIVE The objective of our study was to report the incidence of bleeding after imaging-guided percutaneous core biopsy at a single center using a standardized technique. MATERIALS AND METHODS We performed a retrospective review of percutaneous core biopsies performed at our institution from January 2002 through February 2008. Data were collected at the time of biopsy, and clinical information was obtained 24 hours and 3 months after the biopsy. The specific information that was collected included the results of coagulation studies, aspirin use, the organ biopsied, the size of the biopsy needle, and the number of needle passes. Bleeding complications were defined using the Common Terminology Criteria for Adverse Events (CTCAE, version 3.0) established by the National Cancer Institute. RESULTS Among the 15,181 percutaneous core biopsies performed during the study period, 70 hemorrhages (0.5%) that were CTCAE grade 3 or greater were identified within 3 months of biopsy. The incidence of bleeding in patients taking aspirin within 10 days before biopsy was 0.6% (18/3,195), which was not statistically different compared with the incidence of bleeding in those not taking aspirin (52/11,986, 0.4%; p = 0.34). The incidence of bleeding after liver biopsy was 0.5%; kidney biopsy, 0.7%; lung biopsy, 0.2%; pancreas biopsy, 1.0%; and other biopsy, 0.2%. There were significant associations between major bleeding and serum platelet count and international normalized ratio (p < 0.001), although the association between major bleeding and the size of the biopsy needle was not significant (p = 0.97). CONCLUSION The overall incidence of major bleeding after imaging-guided percutaneous core needle biopsy is low. Recent aspirin therapy does not appear to significantly increase the risk of such bleeding complications.


Clinical Gastroenterology and Hepatology | 2004

Comparison of the relative sensitivity of CT colonography and double-contrast barium enema for screen detection of colorectal polyps

C. Daniel Johnson; Robert L. MacCarty; Timothy J. Welch; Lynn A. Wilson; William S. Harmsen; Duane M. Ilstrup; David A. Ahlquist

BACKGROUND & AIMS In a population reflective of a screening setting, our aim was to compare the relative sensitivity and specificity of computed tomography (CT) colonography with double-contrast barium enema (DCBE) for detection of colorectal polyps and to assess the added value of double reading at CT colonography, using endoscopy as the arbiter. METHODS This prospective, blinded study comprised 837 asymptomatic persons at higher than average risk for colorectal cancer who underwent CT colonography followed by same-day DCBE. Examinations with polyps > or =5 mm in diameter were referred to colonoscopy. RESULTS CT colonography readers detected 56%-79% of polyps > or =10 mm in diameter. In comparison, the sensitivity at DCBE varied between 39% and 56% for the 31 polyps > or =1 cm. All of the readers detected more polyps at CT colonography than DCBE, but the difference was statistically significant for only a single reader (P = 0.02). Relative specificity for polyps > or =10 mm on a per-patient basis ranged from 96% to 99% at CT colonography, and 99%-100% at DCBE. Doubly read CT colonography detected significantly more polyps than DCBE (81% vs. 45% for polyps > or =1 cm [P = <0.01], and 72% vs. 44% for polyps 5-9 mm [P < or = 0.01]). CONCLUSIONS Double-read CT colonography is significantly more sensitive in detecting polyps than single-read double contrast barium enema. DCBE was significantly more specific than CT colonography.


Annals of Vascular Surgery | 1992

The Role of Intravenous Fluorescein in the Detection of Colon Ischemia During Aortic Reconstruction

R. Thomas Bergman; Peter Gloviczki; Timothy J. Welch; James M. Naessens; Thomas C. Bower; John W. Hallett; Peter C. Pairolero; Kenneth J. Cherry

Intravenous fluorescein is an accurate predictor of small bowel viability, but its effectiveness in assessing colon perfusion during aortic surgery has not been evaluated. Over a 10 year period 186 of 3,306 patients undergoing aortic reconstruction received 500 to 1000 mg of intravenous fluorescein intraoperatively to evaluate colon viability. Prior history of colectomy, hypogastric or mesenteric arterial occlusive disease, or ruptured aneurysm placed these patients at risk to develop ischemic colitis. Patients were operated on for aneurysmal disease (n=94), occlusive disease (n= 66), or a combination of both (n=26): 171 exhibited uniform normal perfusion patterns under Woods lamp illumination, while in 11 it was “patchy.” None of these patients developed full-thickness ischemic colitis (observed specificity: 100%). Fluorescence of the rectosigmoid was absent in four patients. One of these patients with a ruptured aneurysm underwent immediate sigmoid resection, while three underwent inferior mesenteric artery reimplantation. The fluorescein pattern subsequently normalized in two patients, but one underwent sigmoid resection for an expanding mesenteric hematoma. The second patient recovered without complications. The final patient continued to show a segmental sigmoid defect and postoperatively developed full-thickness injury requiring sigmoidectomy. During the same period 18 other patients developed transmural colon ischemia from 3,120 aortic reconstructions (0.6%), with a mortality rate of 56%. None had received intraoperative fluorescein. Selective use of intravenous fluorescein may reduce the mortality of ischemic colitis following aortic reconstruction.


Journal of Vascular Surgery | 1990

Multiple aortic aneurysms : the results of surgical management

Peter Gloviczki; Peter C. Pairolero; Timothy J. Welch; Kenneth J. Cherry; John W. Hallett; Barbara J. Toomey; James M. Naessens; Thomas A. Orszulak; Hartzell V. Schaff

During the past 2 decades 102 consecutive patients (77 men and 25 women) with multiple aortic aneurysms underwent 201 aortic reconstructions. These procedures (174 elective and 27 emergent) represented 3.4% of the 5837 aortic aneurysm operations performed. Seventy-five (30.9%) of the 243 aneurysms occurred in the infrarenal aorta, 65 occurred in the descending aorta (26.7%), 56 occurred in the thoracoabdominal aorta (23.0%), and 47 occurred in the ascending aorta or arch (19.3%). Ages ranged from 20 to 81 years (mean 63.3 years). Smoking history and abnormal electrocardiographic tracings were present in 84.3% of the patients, hypertension was present in 77.5%, and obstructive lung disease was present in 60.8%. Multiple aortic aneurysms were present at the time of the first repair in 55 patients (53.9%). Twelve patients had one procedure, 81 had two, and nine had three. Sixteen (17.8%) of the 90 patients who had multiple operations had a subsequent operation for complications of the unrepaired aneurysm (rupture 12, symptoms 4). Fourteen perioperative deaths occurred among the 174 elective repairs (8.0%), and 11 occurred among the 27 emergent procedures (40.7%). Procedure mortality increased with the ordinal number of elective operations and was 4.4% for the first, 10.4% for the second, and 33.3% for the third. Seven of 21 patients (33.3%) who had simultaneous repair of at least two aortic aneurysms died in the perioperative period. Overall, 77 of the 102 patients (75.5%) survived all surgical procedures to repair their multiple aortic aneurysms; of these, 63 had complete resection of all known aneurysms. Follow-up was complete in all patients and averaged 6.3 years (ranges: 1 month to 19 years). There were 30 late deaths; the most frequent cause was myocardial infarction. Kaplan-Meier 5-year survival including perioperative deaths for all patients after the first operation was 76% and after the last operation 40%. We conclude that multiple aortic aneurysms can be safely managed, usually with staged repairs, and that long-term survival is probably. After the first aortic operation the presence of multiple aneurysms mandates close observation with timely surgical intervention.

Collaboration


Dive into the Timothy J. Welch's collaboration.

Researchain Logo
Decentralizing Knowledge