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Amy K Hara

Publications and source records attributed to Amy K Hara.

15 recordsLinked to original sources
PubMed2006

Assessment of polyp and mass histopathology by intravenous contrast-enhanced CT colonography.

RATIONALE AND OBJECTIVES: We sought to demonstrate that intravenous contrast-enhanced CT colonography (CTC) can distinguish colonic adenomas from carcinomas. METHODS: Supine intravenous contrast-enhanced CTC with colonoscopic and/or surgical correlation was performed on 25 patients with colonic adenomas or carcinomas. Standard deviation of mean polyp CT attenuation was computed and assessed using ANOVA and receiver-operating characteristic analyses. RESULTS: Colonoscopy confirmed 32 polyps or masses 1 to 8 cm in size. The standard deviations of CT attenuation were carcinomas (n = 13; 36 +/- 6 HU; range 28-48 HU) and adenomas (n = 19; 49 +/- 14 HU; range 31-100 HU) (P = 0.005). At a standard deviation threshold of 42 HU, the sensitivity and specificity for classifying a polyp or mass as a carcinoma were 92% and 79%, respectively. The area under the receiver-operating characteristic curve was 0.89 +/- 0.06 (95% confidence interval 0.73-0.96). CONCLUSIONS: Measurement of the standard deviation of CT attenuation on intravenous contrast-enhanced CTC permits histopathologic classification of polyps 1 cm or larger as carcinomas versus adenomas. The presence of ulceration or absence of muscular invasion in carcinomas creates overlap with adenomas, reducing the specificity of carcinoma classification.

Adenoma↗
PubMed2006

Colonic perforation after computed tomographic colonography in a patient with fibrostenosing Crohn's disease.

Computed tomographic colonography (CTC) offers great promise in the management of patients with disorders of the colon. Few complications have been reported with its use thus far. We describe herein a case of colonic perforation during CTC in a patient with active stenosing ileocolonic Crohn's disease. To our knowledge, this is the first reported case of CTC-related perforation in the setting of Crohn's disease, and the third reported perforation overall. Perforation likely occurred in this case due to barotrauma in the setting of colonic strictures and an inflamed, weakened colonic wall. Physician awareness of the increased risk of perforation with CTC in the setting of inflammatory and/or obstructive disease of the colon will allow for improved clinical decision-making in the care of these patients.

Anastomosis, Surgical↗
PubMed2006

A meta-analysis of the yield of capsule endoscopy compared to other diagnostic modalities in patients with non-stricturing small bowel Crohn's disease.

OBJECTIVES: Capsule endoscopy (CE) allows for direct evaluation of the small bowel mucosa in patients with Crohn's disease (CD). A number of studies have revealed significantly improved yield for CE over other modalities for the diagnosis of CD, but as sample sizes have been small, the true degree of benefit is uncertain. Additionally, it is not clear whether patients with a suspected initial presentation of CD and those with suspected recurrent disease are equally likely to benefit from CE. The aim of this study was to evaluate the yield of CE compared with other modalities in symptomatic patients with suspected or established CD using meta-analysis. METHODS: We performed a recursive literature search of prospective studies comparing the yield of CE to other modalities in patients with suspected or established CD. Data on yield among various modalities were extracted, pooled, and analyzed. Incremental yield (IY) (yield of CE--yield of comparative modality) and 95% confidence intervals (95% CI) of CE over comparative modalities were calculated. Subanalyses of patients with a suspected initial presentation of CD and those with suspected recurrent disease were also performed. RESULTS: Nine studies (n = 250) compared the yield of CE with small bowel barium radiography for the diagnosis of CD. The yield for CE versus barium radiography for all patients was 63% and 23%, respectively (IY = 40%, p < 0.001, 95% CI = 28-51%). Four trials compared the yield of CE to colonoscopy with ileoscopy (n = 114). The yield for CE versus ileoscopy for all patients was 61% and 46%, respectively (IY = 15%, p= 0.02, 95% CI = 2-27%). Three studies compared the yield of CE to computed tomography (CT) enterography/CT enteroclysis (n = 93). The yield for CE versus CT for all patients was 69% and 30%, respectively (IY = 38%, p= 0.001, 95% CI = 15-60%). Two trials compared CE to push enteroscopy (IY = 38%, p < 0.001, 95% CI = 26-50%) and one trial compared CE to small bowel magnetic resonance imaging (MRI) (IY = 22%, p= 0.16, 95% CI =-9% to 53%). Subanalysis of patients with a suspected initial presentation of CD showed no statistically significant difference between the yield of CE and barium radiography (p= 0.09), colonoscopy with ileoscopy (p= 0.48), CT enterography (p= 0.07), or push enteroscopy (p= 0.51). Subanalysis of patients with established CD with suspected small bowel recurrence revealed a statistically significant difference in yield in favor of CE compared with all other modalities (barium radiography (p < 0.001), colonoscopy with ileoscopy (p= 0.002), CT enterography (p < 0.001), and push enteroscopy (p < 0.001)). CONCLUSIONS: In study populations, CE is superior to all other modalities for diagnosing non-stricturing small bowel CD, with a number needed to test (NNT) of 3 to yield one additional diagnosis of CD over small bowel barium radiography and NNT = 7 over colonoscopy with ileoscopy. These results are due to a highly significant IY with CE over all other modalities in patients with established non-stricturing CD being evaluated for a small bowel recurrence. While there was no significant difference seen between CE and alternate modalities for diagnosing small bowel CD in patients with a suspected initial presentation of CD, the trend toward significance for a number of modalities suggests the possibility of a type II error. Larger studies are needed to better establish the role of CE for diagnosing small bowel CD in patients with a suspected initial presentation of CD.

Barium Sulfate↗
PubMed2006

Crohn disease of the small bowel: preliminary comparison among CT enterography, capsule endoscopy, small-bowel follow-through, and ileoscopy.

PURPOSE: To prospectively compare four diagnostic small-bowel imaging techniques for depiction of abnormal findings in the same patients known to have or suspected of having Crohn disease. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Patients known to have or suspected of having nonobstructive Crohn disease were recruited. Each patient underwent capsule endoscopy, computed tomographic (CT) enterography, colonoscopy with ileoscopy, and small-bowel follow-through (SBFT). Findings consistent with Crohn disease were tabulated for each imaging examination (diagnostic yield). The proportions of patients with positive findings at each examination were compared, and any significant differences between the tests were calculated by using the exact McNemar test. RESULTS: Seventeen patients (nine women, eight men; mean age, 49 years; range, 18-78 years) completed the study out of 20 patients enrolled. Crohn disease was depicted by capsule endoscopy in 12 patients (71%), ileoscopy in 11 (65%), CT enterography in nine (53%), and SBFT in four (24%). Ileoscopy was incomplete in four patients, and capsule endoscopy was incomplete in two patients. Capsule endoscopy had the highest diagnostic yield for Crohn disease, and SBFT had the lowest, but these differences were not statistically significant (P = .02). SBFT failed to depict a stricture in one patient, which resulted in surgical removal of the capsule. CT enterography and SBFT depicted extraintestinal findings (eg, mesenteric adenopathy in two patients, perianal and enterocolic fistulas in one patient) not detected endoscopically. CONCLUSION: This preliminary study demonstrates capsule endoscopy and CT enterography may depict nonobstructive Crohn disease when techniques such as ileoscopy and SBFT have negative or inconclusive findings.

Adolescent↗
PubMed2005

Extracolonic findings at CT colonography.

CT colonography (CTC), also referred to as virtual colonoscopy, is a noninvasive CT examination of the colon. Usually performed without IV contrast, it allows detection of both intraluminal and extraluminal (extracolonic) disease. Several studies demonstrate that although extracolonic disease at CTC is found in the majority of patients, the detection of previously undiagnosed highly important findings (HIF) is much lower. The number of HIF can vary depending on the definition of an HIF, the patient population, as well as technical factors. This article will discuss the incidence and implication of detecting extracolonic findings at CTC.

Aged↗
PubMed2005

A meta-analysis of the yield of capsule endoscopy compared to other diagnostic modalities in patients with obscure gastrointestinal bleeding.

OBJECTIVES: Due to its superior ability to examine the entire small bowel mucosa, capsule endoscopy (CE) has broadened the diagnostic evaluation of patients with obscure gastrointestinal bleeding (OGIB). Published studies have revealed a numerically superior performance of CE in determining a source of OGIB compared with other modalities, but due to small sample sizes, the overall magnitude of benefit is unknown. Additionally, the types of lesions more likely to be found by CE versus alternate modalities are also unknown. The aim of this study was to evaluate the yield of small bowel findings with CE in patients with OGIB compared to other modalities using meta-analysis. METHODS: We performed a recursive literature search of prospective studies comparing the yield of CE to other modalities in patients with OGIB. Data on yield and types of lesions identified among various modalities were extracted, pooled, and analyzed. Incremental yield (IY) (yield of CE-yield of comparative modality) and 95% confidence intervals (95% CI) of CE over comparative modalities were calculated. RESULTS: A total of 14 studies (n = 396) compared the yield of CE with push enteroscopy for OGIB. The yield for CE and push enteroscopy was 63% and 28%, respectively (IY = 35%, p < 0.00001, 95% CI = 26-43%) and for clinically significant findings (n = 376) was 56% and 26%, respectively (IY = 30%, p < 0.00001, 95% CI = 21-38%). Three studies (n = 88) compared the yield of CE to small bowel barium radiography. The yield for CE and small bowel barium radiography for any finding was 67% and 8%, respectively (IY = 59%, p < 0.00001, 95% CI = 48-70%) and for clinically significant findings was 42% and 6%, respectively (IY = 36%, p < 0.00001, 95% CI = 25-48%). Number needed to test (NNT) to yield one additional clinically significant finding with CE over either modality was 3 (95% CI = 2-4). One study each compared the yield of significant findings on CE to intraoperative enteroscopy (n = 42, IY = 0%, p= 1.0, 95% CI =-16% to 16%), computed tomography enteroclysis (n = 8, IY = 38%, p= 0.08, 95% CI =-4% to 79%), mesenteric angiogram (n = 17, IY =-6%, p= 0.73, 95% CI =-39% to 28%), and small bowel magnetic resonance imaging (n = 14, IY = 36%, p= 0.007, 95% CI = 10-62%). Ten of the 14 trials comparing CE with push enteroscopy classified the types of lesions found on examination. CE had a 36% yield for vascular lesions versus 20% for push enteroscopy, with an IY of 16% (p < 0.00001, 95% CI = 9-23%). Inflammatory lesions were also found more often in CE (11%) than in push enteroscopy (2%), with an IY of 9% (p= 0.0001, 95% CI = 5-13%). There was no significant difference in the yield of tumors or "other" findings between CE and push enteroscopy. CONCLUSIONS: CE is superior to push enteroscopy and small bowel barium radiography for diagnosing clinically significant small bowel pathology in patients with OGIB. In study populations, the IY of CE over push enteroscopy and small bowel barium radiography for clinically significant findings is >or=30% with an NNT of 3, primarily due to visualization of additional vascular and inflammatory lesions by CE.

Barium Sulfate↗
PubMed2003

Small bowel: preliminary comparison of capsule endoscopy with barium study and CT.

PURPOSE: To retrospectively compare capsule endoscopic (CE) findings with findings at barium studies or computed tomography (CT) in patients without evidence of small-bowel stricture at barium examination. MATERIALS AND METHODS: Fifty-two patients underwent CE, and the majority (43 of 52) did so for obscure gastrointestinal bleeding. Forty-two (81%) of 52 patients underwent 36 small-bowel follow-through examinations; four, enteroclysis; and 19, contrast material-enhanced CT of the abdomen and pelvis within 6 months of CE (either before or after CE). Imaging results were retrospectively reviewed and compared with CE, standard endoscopic, and surgical results. Findings of any examinations between CE and imaging that were discrepant were retrospectively reviewed by a radiologist not blinded to CE results. Proportion of positive findings at CE was compared with proportion of positive findings at barium studies and CT in the same patients. Statistical significance was calculated with McNemar chi2 statistic. RESULTS: Barium examination findings were positive in one (3%) of 40 patients; CE findings were positive in 22 (55%) (P <.001). CT demonstrated small-bowel findings in four (21%) of 19 patients, but CE demonstrated findings in 12 (63%) of 19 patients (P =.02). The most common CE finding, angioectasia (n = 11), was not detected at any imaging study. More ulcers (n = 8) were detected with CE than with barium study (one of eight) and CT (three of six). At CE, three of five surgically confirmed masses (carcinoid, intussusception, lymphangioma) were identified, but two jejunal tumors were not detected in a patient with poor bowel preparation. At barium study, no masses (zero of five) were detected; at CT, one of four masses was detected. CONCLUSION: In patients without a small-bowel stricture at barium study, more small-bowel disease was found at CE when findings were retrospectively compared with barium examination and CT findings.

Adult↗
PubMed2003

Computerized tomographic colonography: performance evaluation in a retrospective multicenter setting.

BACKGROUND & AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Colonic Neoplasms↗
PubMed2002

The future of colorectal imaging: computed tomographic colonography.

The development of colorectal cancer screening alternatives that are attractive to patients and effective for screening is critical for reducing this too-common and deadly disease. CTC is an exciting technique that is the only imaging alternative developed since the barium enema for colon screening. In the past few years, many obstacles to clinical implementation of CTC have been eliminated. For example, there is no longer any post-processing time, which was previously as long as 8 to 10 hours, and the interpretation time has been drastically reduced from 4 hours to 15 to 20 minutes. The majority of studies have demonstrated excellent results for detection of lesions > or = 1 cm, with few false positives. This examination will continue to improve with the development of automated (computer) detection programs and automated 3D rendering algorithms. In addition, cathartic bowel preparation, one of the biggest obstacles to patient compliance with colorectal cancer screening, may be eliminated if successful fecal tagging can be developed. The most important issue that remains is its performance in a screening population, and studies are currently underway to answer that important question.

Clinical Trials as Topic↗
PubMedDate not supplied

MR cholangiopancreatography: improved ductal distention with intravenous morphine administration.

Magnetic resonance (MR) cholangiopancreatography has proved a robust and noninvasive imaging modality for evaluating the biliary and pancreatic ducts without the use of ionizing radiation. Although MR cholangiopancreatography reliably depicts the main extrahepatic and intrahepatic bile ducts, it does not depict the segmental intrahepatic ducts unless they are dilated. The segmental ducts are difficult to visualize with MR cholangiopancreatography because of their small caliber and the limited spatial resolution and signal-to-noise ratio achievable with standard MR pulse sequences. However, visualization of the normal (ie, nondistended) biliary system is necessary for the evaluation of donor candidates for living related liver transplantation. Because of the prevalence of variant biliary anatomy, MR cholangiopancreatography is often used for preoperative evaluation of prospective liver donors. Intravenous morphine administered prior to MR cholangiopancreatography can improve image quality by causing the sphincter of Oddi to contract, which increases pressure in and distention of the biliary and pancreatic ducts. Morphine administration may also be particularly helpful for the evaluation of patients with primary sclerosing cholangitis, malignant neoplasms such as cholangiocarcinoma, or cystic and non-organ-deforming benign pancreatic neoplasms.

Bile Duct Diseases↗
PubMedDate not supplied

Imaging of small bowel disease: comparison of capsule endoscopy, standard endoscopy, barium examination, and CT.

Capsule endoscopy is a revolutionary new diagnostic tool for the detection of small bowel disease. As the name implies, capsule endoscopy makes use of a swallowable video capsule; as such, it is the only technique that allows noninvasive endoscopic examination of the entire small bowel without sedation. Obscure gastrointestinal bleeding is the most common indication for capsule endoscopy, which commonly depicts arteriovenous malformations, small bowel tumors, and ulcers missed at standard endoscopy and imaging examinations. However, capsule endoscopy is not optimal for the localization of small bowel lesions. In addition, lesions can be missed due to poor bowel preparation, rapid or delayed small bowel transit, or orientation of the camera away from a lesion. Computed tomography and barium examinations are useful for detecting these missed lesions and for localizing lesions detected at capsule endoscopy. Other limitations of capsule endoscopy are the inability to treat lesions and its limited use in patients with small bowel strictures or obstruction. Nevertheless, this new technique is easy to perform, is well tolerated by patients, and, for the first time, allows noninvasive endoscopic evaluation of the entire small bowel.

Barium Sulfate↗
PubMedDate not supplied

CT colonography with intravenous contrast material: varied appearances of colorectal carcinoma.

Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that has been shown in some studies to be comparable with conventional colonoscopy for the screening of colorectal cancer. Because colorectal cancer has a widely varying appearance at both endoscopy and CT colonography, familiarity with the gamut of morphologic appearances can help improve interpretation of the results. The addition of intravenous contrast material to CT colonography can aid differentiation of true colonic masses from pseudolesions such as residual stool and improves the depiction of enhancing masses that might otherwise be obscured by residual colonic fluid. In contrast to staging of most other tumors, staging of colorectal carcinoma depends more on the depth of tumor invasion than on the size of the primary mass. The diverse appearances of colorectal cancers at two- and three-dimensional CT colonography include sessile, annular, ulcerated, necrotic, mucinous, invasive, and noninvasive lesions. Imaging pitfalls that can simulate or obscure neoplasms are retained fecal material or fluid, incomplete distention, and advanced diverticulosis.

Colonography, Computed Tomographic↗
PubMedDate not supplied

Evaluation of benign and malignant rectal lesions with CT colonography and endoscopic correlation.

Colorectal carcinoma is a significant cause of death from cancer in the United States, and early detection and treatment are critical. Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that is a potential alternative to conventional colonoscopy for colorectal cancer screening. Rectal disease (eg, polyps, cancerous lesions, extramucosal lesions, inflammatory disease) can be especially challenging to diagnose with CT colonography because of several factors that can simulate or obscure the disease (eg, over- or underdistention, rectal tube, stool, artifacts). Familiarity with the spectrum of rectal diseases and with the potential pitfalls and technical limitations of CT colonography will help minimize interpretative and perceptual errors.

Colonography, Computed Tomographic↗
PubMedDate not supplied

Three-dimensional virtual dissection at CT colonography: unraveling the colon to search for lesions.

Computed tomographic (CT) colonography is a promising noninvasive examination for colorectal cancer screening; however, the optimal interpretation strategy remains undecided. Virtual dissection is an innovative technique whereby the three-dimensional (3D) model of the colon is virtually unrolled, sliced open, and displayed as a flat 3D rendering of the mucosal surface, similar to a gross pathologic specimen. This technique has the potential to reduce evaluation time by providing a more rapid 3D image assessment than is possible with an antegrade and retrograde 3D endoluminal fly-through. It may also ultimately improve accuracy by reducing blind spots present with 3D endoluminal displays and by reducing reader fatigue. A disadvantage of virtual dissection is the potential for distortion of colonic lesions and normal anatomy. To avoid potential pitfalls in image interpretation, the radiologist must be familiar with the unique appearance of the normal colon anatomy and of various pathologic findings when using virtual dissection with two-dimensional axial and 3D endoluminal CT colonographic image data sets.

Colonic Diseases↗