R E Koehler

University of Alabama at Birmingham, Birmingham, AL, United States

Are you R E Koehler?

Claim your profile

Publications (76)338.21 Total impact

  • Cheri L Canon · Robert J Stanley · Richard Pierce · Robert E Koehler
    No preview · Article · Apr 2006 · Journal of the American College of Radiology: JACR
  • Cheri L Canon · Susan Mulligan · Robert E Koehler
    [Show abstract] [Hide abstract] ABSTRACT: To organize and implement a mock oral examination for radiology residents in an attempt to prepare them for the American Board of Radiology Oral Examination. A mock oral examination was administered to junior and senior radiology residents by radiology faculty. All participants completed postexamination surveys. The mock oral examination process not only provided practice for preboard residents, but also determined areas of deficiency in their fund of knowledge and presenting skills. Additionally, it provided faculty members with areas of curricular weakness. Administration of a mock oral examination reaps multiple benefits, which far exceed the task of its implementation.
    No preview · Article · Apr 2005 · Academic Radiology
  • [Show abstract] [Hide abstract] ABSTRACT: The purpose of our study was to determine the effectiveness, clinical impact, and feasibility of double reading barium enemas. Independent double readings of 1,003 consecutive barium enemas (822 double- and 181 single-contrast examinations) were prospectively performed. From this pool of 1,003 examinations, 994 were included in our study. Examinations showing at least one polyp or carcinoma 5 mm or larger were considered to have positive results. For combined readings, results were considered positive if either of the two interpreters reported finding a polyp or carcinoma. A McNemar test was used to compare the first reader's results with the combined results of the first and second readers. Results were retrospectively correlated with endoscopic or surgical results in 360 patients, and agreement between first and combined readings and endoscopic results was determined. Adding a second reader increased the number of positive results on examinations from 249 to 315 (p < 0.0001) and resulted in potential alteration of clinical treatment in 98 patients (9.9%). Sensitivity of the first and combined readings for detection of all lesions was identical, 76.3% (95% CI, 65.4-87.1%). Specificity decreased from 91.0% (95% CI, 87.9-94.3%) for the first reading to 86.4% (95% CI, 82.2-90.0%) for the combined reading. The overall measurement of agreement decreased from a kappa value of 61.8 (95% CI, 51.2-72.4%) for the first reading to 52.9 (95% CI, 42.2-63.6%) for the combined reading. The second reading required an average of 3.3 min. Sensitivity for the detection of adenocarcinomas was 100%. Although feasible, double reading of barium enemas does not improve sensitivity for detection of polyps and produces a higher false-positive rate.
    No preview · Article · Jan 2004 · American Journal of Roentgenology
  • [Show abstract] [Hide abstract] ABSTRACT: No multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps >or=10 mm in diameter) in a multi-institutional study. A retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers. Colonoscopy and pathology reports provided the standard. A random sample of 117 patients, stratified by criterion standard, was requested. Ninety-three patients were included (47% with polyps >or=10 mm; mean age, 62 years; 56% men; 84% white; 40% reported colorectal symptoms; 74% at increased risk for colorectal cancer). Eighteen radiologists blinded to the criterion standard interpreted computerized tomography colonography examinations, each using 2 of 3 different software display platforms. The average area under the receiver operating characteristic curve for identifying patients with at least 1 lesion >or=10 mm was 0.80 (95% lower confidence bound, 0.74). The average sensitivity and specificity were 75% (95% lower confidence bound, 68%) and 73% (95% lower confidence bound, 66%), respectively. Per-polyp sensitivity was 75%. A trend was observed for better performance with more observer experience. There was no difference in performance across software display platforms. Computerized tomographic colonography performance compared favorably with reported performance of fecal occult blood testing, flexible sigmoidoscopy, and barium enema. A prospective study evaluating the performance of computerized tomography colonography in a screening population is indicated.
    No preview · Article · Sep 2003 · Gastroenterology
  • [Show abstract] [Hide abstract] ABSTRACT: Our purpose was to determine the frequency of intramural tracking in patients with esophageal intramural pseudodiverticulosis and to characterize the morphologic features of this finding on barium studies. A review of radiology files at two institutions revealed 30 cases of esophageal intramural pseudodiverticulosis diagnosed at esophagography. In all cases, the radiographs were reviewed retrospectively to determine the frequency and morphologic features of intramural tracking in these patients. The number and distribution of pseudodiverticula and the presence or absence of strictures or esophagitis were also noted. Fifteen (50%) of 30 patients with esophageal intramural pseudodiverticulosis had intramural tracking on esophagography. The tracks had an average length of 1.2 cm (length range, 0.3-7 cm) and an average width of 1.6 mm (width range, 1-4 mm). The pseudodiverticula were more numerous and had a more diffuse distribution in patients with tracking than in patients without tracking. Although patients with and without tracking had a similar frequency of strictures and esophagitis, patients with tracking were more likely to have strictures involving the upper or mid esophagus, whereas patients without tracking were more likely to have strictures in the distal esophagus. These findings indicate that intramural tracking is more likely to occur in patients with the diffuse form of esophageal intramural pseudodiverticulosis. Intramural tracking was detected on esophagography in 50% of patients with esophageal intramural pseudodiverticulosis, so this type of tracking is a more common radiographic finding than has previously been recognized. Although intramural tracking has little or no known clinical significance, it is important to be aware of this finding so that it is not mistaken for a large flat ulcer in the esophagus or for an extramural collection associated with esophageal peridiverticulitis.
    No preview · Article · Sep 2000 · American Journal of Roentgenology
  • No preview · Article · Aug 2000 · American Journal of Roentgenology
  • Matthew A. Mauro · Robert E. Koehler · Todd H. Baron
    [Show abstract] [Hide abstract] ABSTRACT: Metallic stents are currently an established component of the endoluminal treatment of stenoses within the blood vessels, bile ducts, esophagus, trachea, and bronchi. With the development of newer stent designs and delivery systems and the general momentum toward minimally invasive therapies, metallic stent placement has expanded into the nonsurgical therapy for gastroduodenal and colorectal obstructions. The use of metallic stents within the stomach, duodenum, or colon is intended not to be curative but to provide nonsurgical palliation for the symptoms of gastric or colonic obstruction. This palliation may be intended for the life of the patient in the case of unresectable disease or as a temporizing procedure prior to a definitive surgical procedure. In the latter clinical scenario, the benefits of a minimally invasive intestinal decompression procedure include (a) quick and noninvasive relief of the intestinal obstruction in an acutely ill patient that obviates a more extensive procedure; (b) allowance of time to improve a patient's overall medical condition and thus to allow a patient to better tolerate the definitive surgical procedure; and (c) reduction of the complexity of the definitive procedure by eliminating the need for staged procedures and allowing the definitive procedure to be performed at one setting.
    No preview · Article · Jul 2000 · Radiology
  • Source
    D E Morgan · K Logan · T H Baron · R E Koehler · J K Smith
    [Show abstract] [Hide abstract] ABSTRACT: The purpose of our study was to determine the prevalence, distribution, and clinical significance of pancreatic ductal changes due to pancreatitis on ERCP in patients with pancreas divisum. From January 1993 through December 1997, 1714 patients underwent 2469 ERCP studies. Ninety-four patients (5.5%) had pancreas divisum. Retrospective review of the spot radiographs was performed to establish the presence and location of pancreatitis. Clinical indications for and therapy during ERCP were correlated with radiographic findings. Of the 94 patients with pancreas divisum, 54 (57%) had radiographic evidence of pancreatitis. Of these 54 patients, 44 had at least one episode of clinically documented pancreatitis, seven had recurrent abdominal pain, and three underwent ERCP for biliary indications. In 76% of the 54 patients with radiographic evidence of pancreatitis, only the dorsal system showed irreversible inflammatory change (p < .0001). Acute recurrent pancreatitis was the most common indication for ERCP in divisum patients and was statistically more common than in pancreatitis patients with normal anatomy (p < .0001). Sixty-two (66%) of the 94 patients with pancreas divisum underwent endoscopic pancreatic intervention, most commonly minor papilla sphincterotomy or stenting or both. Eleven patients with clinically documented pancreatitis had no abnormalities revealed by ERCP. In our population of patients referred for ERCP and found to have pancreas divisum, the prevalence of pancreatitis was very high and usually was limited to a dorsal distribution.
    Full-text · Article · Jul 1999 · American Journal of Roentgenology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: The in vivo radiographic features of two commercially available formulations of barium used as contrast media in dedicated small-bowel series were compared. Fifty-six consecutive outpatients referred for a dedicated small-bowel series were randomly administered either E-Z-Paque or Entrobar. Representative survey radiographs from each examination were randomized and reviewed by six gastrointestinal radiologists from three institutions. Each observer assigned a numeric score (1 = poor, 2 = fair, 3 = good, and 4 = excellent) that rated the quality of the radiograph with respect to these characteristics: definition of fold pattern, translucency, distention, and integrity of the barium column. Statistical analysis was performed for each characteristic using Wilcoxon's two-sample rank sum test. All six observers found a statistically significant difference between the two barium formulations for mean scores for definition of fold pattern and translucency. Mean scores for fold pattern were 3.3, 3.0, 3.2, 3.6, 3.3, and 3.4 for Entrobar and 2.1, 2.3, 2.4, 3.2, 2.6, and 2.7 for E-Z-Paque. Mean scores for translucency were 2.5, 2.7, 2.8, 3.1, 2.7, and 3.3 for Entrobar and 1.6, 1.7, 2.1, 2.3, 1.9, and 2.7 for E-Z-Paque. No statistically significant difference was found for mean score for distention or integrity of the barium column. On radiographs, Entrobar was found to have superior characteristics for visualization of fold pattern and translucency but offered no advantages for distention or integrity of the barium column. Improved translucency and definition of fold pattern may translate into improved sensitivity and confidence in diagnosing small-bowel abnormality.
    Full-text · Article · Mar 1999 · American Journal of Roentgenology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Intrasphincteric injection of botulinum toxin is a new treatment option for achalasia. To compare the immediate and long term efficacy of botulinum toxin with that of pneumatic dilatation. Symptomatic patients with achalasia were randomised to botulinum toxin (22 patients, median age 57 years) or pneumatic dilatation (20 patients, median age 56 years). Symptom scores were assessed initially, and at one, three, six, nine, and 12 months after treatment. Objective assessment included oesophageal manometry initially and at one month, and barium oesophagram initially and at one, six, and 12 months post-treatment. Pneumatic dilatation resulted in a significantly (p=0.02) higher cumulative remission rate. At 12 months, 14/20 (70%) pneumatic dilatation and 7/22 (32%) botulinum toxin treated patients were in symptomatic remission (p=0.017). Failure rates were similar initially, but failure over time was significantly (p=0.01) higher after botulinum toxin (50%) than pneumatic dilatation (7%). Pneumatic dilatation resulted in significant (p<0.001) reduction in symptom scores, and lower oesophageal sphincter pressure, oesophageal barium column height, and oesophageal diameter. Botulinum toxin produced significant reduction in symptom scores (p<0.001), but no reduction in objective parameters. At one year pneumatic dilatation is more effective than botulinum toxin. Symptom improvement parallels objective oesophageal measurements after pneumatic dilatation but not after botulinum toxin treatment for achalasia.
    Full-text · Article · Feb 1999 · Gut
  • [Show abstract] [Hide abstract] ABSTRACT: The authors attempted to determine whether videotaping the fluoroscopic portion of hysterosalpingography would result in changed diagnoses or an increase in diagnostic confidence. Ninety-nine consecutive outpatients underwent routine hysterosalpingography. The fluoroscopic portion of the examination was captured on videotape. Two consecutive interpretations of each hysterosalpingogram were made by attending radiologists. First, spot radiographs were interpreted alone. Second, these images were viewed along with videofluoroscopy. Concordance of and confidence in findings for the two interpretations were assessed with the two-tailed Fisher exact test. Interpretations of spot radiographs alone and with videofluoroscopy were in agreement in 92 of 99 uterine examinations and 164 of 198 tubal examinations. For uterine examinations classified as normal, interpretations of spot radiographs and videofluoroscopy were in agreement in 56 of 57 cases; there was no change in confidence with review of videofluoroscopic images. For uterine examinations interpreted as abnormal, agreement was noted in 36 of 42 cases (P = .04), and confidence increased with videofluoroscopy in 10 of 42 cases (P = .00001). With normal tubal findings, interpretations agreed in 94 of 118 cases, and confidence increased in 56 of 118 cases (P = .002). With abnormal tubal findings, interpretations agreed in 70 of 80 cases, and confidence increased in 20 of 80 cases (P = .002). When findings with and without videofluoroscopy were discordant, confidence was always higher after review of video-fluoroscopic images. Review of videofluoroscopic images obtained during hysterosalpingography increases the accuracy and confidence of diagnoses compared with review of spot radiographs alone.
    No preview · Article · Aug 1998 · Academic Radiology
  • [Show abstract] [Hide abstract] ABSTRACT: Acute left-sided colonic obstruction is a surgical emergency whose management is controversial. Because experience using expandable metal stents for relief of this type of obstruction is limited, we evaluated their effectiveness, feasibility, safety, and outcome. Twenty-five patients with acute colorectal obstruction underwent placement of various metal stents under fluoroscopic and endoscopic guidance. On an intent-to-treat basis, stents were placed for decompression before one-stage surgical resection in 10 patients and palliatively in 15 patients. Two preoperative patients had unresectable malignant disease, and stents were left for palliation resulting in 17 palliative and 10 preoperative patients for analysis. Stent placement was technically successful in 94% of patients. Overall effectiveness in relieving obstruction was 85% (palliative 82%, preoperative 90%). In the palliative group, stent duration ranged from 2 to 64 weeks (mean 17.3 weeks). Major complications occurred in 7 patients (30%). Expandable metal stents are a feasible, effective adjunct and alternative to surgery for acute colorectal obstruction.
    No preview · Article · Apr 1998 · Gastrointestinal Endoscopy
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Our purpose was to define a simple technique for timing a barium swallow by which radiologists can assess esophageal emptying in patients with achalasia before and after minimally invasive therapy. Our purpose was also to determine the best method of quantifying the degree of emptying using this timed technique. In the barium swallow technique, upright frontal spot films of the esophagus are obtained at 1, 2, and 5 min after ingestion of 100-200 ml of low-density (45% weight in volume) barium sulfate (volume of barium determined by patient tolerance). Forty-two of these barium swallows done by 23 patients with achalasia were retrospectively reviewed. The examination served either as a baseline study or as a 1-month follow-up study after patients had undergone pneumatic dilatation or Clostridium botulinum toxin injection. The spot films were digitized, and a region of interest was drawn around the column of barium by two observers. The change in area seen in the region of interest on the 1- and 5-min films served as the gold standard for percentage of emptying. The spot films were then analyzed by four other observers, each of whom independently, subjectively, and qualitatively estimated the percentage of emptying between the 1- and 5-min spot films. Percentages were divided into quintiles. On a separate occasion, each of these four observers also independently measured the height and width of the barium column on the 1- and 5-min spot films. The product of height times width seen on the 1- and 5-min films became the quantitative estimate for percentage of emptying. We found no statistically significant difference between the percentage of emptying as measured on the digitized images by the two observers and the height-times-width calculations or qualitative emptying percentage as estimated by the four observers. Interobserver agreement for the area evaluated on the digitized films as well as the height-times-width measurements and qualitative estimates of emptying was almost perfect (the correlation coefficients being 0.99, 0.87, and 0.93, respectively). The timed barium swallow is a simple and reproducible technique. Both qualitative assessment and estimated change in area based on height-times-width measurements of the barium column are accurate methods of estimating esophageal emptying.
    Full-text · Article · Sep 1997 · American Journal of Roentgenology
  • Source
    C L Canon · T H Baron · D E Morgan · P A Dean · R E Koehler
    [Show abstract] [Hide abstract] ABSTRACT: The purpose of this prospective study was to evaluate the efficacy of expandable metal stents for colonic decompression in patients presenting with acute malignant obstruction and to describe the associated radiographic findings. Using both fluoroscopic and endoscopic guidance, we placed expandable metal stents within the colons of 13 patients presenting with acute malignant obstruction. Stents were placed in four patients to permit a standard bowel cleansing before surgical resection with primary anastomosis. In the other nine patients, stents were placed for palliation of nonresectable tumors, obviating colostomy. Outcomes and complications were analyzed. The radiologic aspects of procedural planning, stent placement, assessment after placement, and detection of complications were evaluated. Of the four surgical candidates who were successfully resected with primary anastomosis, two received incomplete bowel cleansing because of stent migration with recurrent obstruction. Eight of the nine patients who had stents placed for palliation of nonresectable tumors had relief of acute obstruction. Complications in this group included two perforations, one that required immediate colostomy and one that was self-limited and conservatively treated. Two other patients of the eight developed early stent obstruction, requiring colostomy in one. The other patient who had a stent placed for palliation of a nonresectable tumor declined further treatment. Contrast-enhanced enema examination proved useful in assessing the suitability of lesions for stent decompression, directing the choice of stent type and the most appropriate position for the patient during the stent placement. Immediately after stent placement, plain abdominal radiographs and water-soluble contrast enema examinations helped us verify stent position and patency. These results suggest that placement of expandable metal stents in patients presenting with acute, malignant colonic obstruction is a viable alternative to colostomy and can potentially decrease morbidity and mortality. Radiologic assessment before, during, and after stent placement plays an integral role in the management of patients undergoing stent decompression of the colon.
    Preview · Article · Feb 1997 · American Journal of Roentgenology
  • Source
    S P Singh · C L Canon · R C Treat · D R Crowe · R H O'Dell · R E Koehler
    Full-text · Article · Feb 1997 · American Journal of Roentgenology
  • TH Baron · PA Dean · CR Shumate · RE Koehler · C Canon
    No preview · Article · Apr 1996 · Gastrointestinal Endoscopy
  • TH Baron · PA Dean · CR Shumate · RE Koehler · C Canon
    No preview · Article · Apr 1996 · Gastrointestinal Endoscopy
  • [Show abstract] [Hide abstract] ABSTRACT: A 75-year-old woman with known systemic mastocytosis presented with abdominal pain, ascites, and bile duct thickening on computed tomography and ultrasonography. A liver biopsy specimen showed infiltration with mast cells. Endoscopic retrograde cholangiography showed ductal changes compatible with those found in primary sclerosing cholangitis. Brush cytology of the intrahepatic bile ducts confirmed mast cell infiltration. Systemic mastocytosis can infiltrate the biliary system, producing a cholangiopathy radiographically similar to primary sclerosing cholangitis.
    No preview · Article · Dec 1995 · Gastroenterology
  • No preview · Article · Apr 1995 · Gastrointestinal Endoscopy
  • [Show abstract] [Hide abstract] ABSTRACT: To conduct a retrospective analysis of one center's experience with treating achalasia over 4 yr with skilled gastroenterologists using primarily the Rigiflex balloon dilator and with a senior surgeon performing Heller myotomies. Newly diagnosed cases of achalasia were identified by a computer search of hospital records. Charts were reviewed for the presence/severity of dysphagia, regurgitation, heartburn, and chest pain. Weight loss was also recorded. Esophageal manometries and barium swallows were reviewed. Choice of treatment was made freely by patients. With an a priori definition of success, follow-up was conducted by telephone interviews. A total of 45 achalasia patients (mean age, 46 yr; 32 females, 13 males) were identified with a symptoms-frequency as follows: dysphagia, 100%; regurgitation, 78%; heartburn, 50%; and chest pain, 42%. Mean weight loss was 17.5 pounds. Primary treatment was pneumatic dilation in 36 patients and surgery in nine patients. In a total of 45 pneumatic dilations, three (6.6%) were complicated by perforation. Five (14%) patients required repeat dilation. Mean duration of follow-up for pneumatic dilation and surgery was 27 months and 20.8 months, respectively. The overall excellent-good success rates were: pneumatic dilation 88% and surgery 89%. In comparing the efficacy of pneumatic dilation versus surgery, all symptoms were improved significantly (p < 0.01) in both groups, except heartburn, which increased postmyotomy. If both procedures are available by skilled operators, pneumatic dilation and surgery are equally effective in the treatment of achalasia.
    No preview · Article · Jul 1994 · The American Journal of Gastroenterology

Publication Stats

3k Citations
338.21 Total Impact Points


  • 1987-1998
    • University of Alabama at Birmingham
      • Department of Radiology
      Birmingham, AL, United States
  • 1995
    • Indiana University-Purdue University Indianapolis
      Indianapolis, Indiana, United States