Biomedical subjects

Mohammed A Kara

Publications and source records attributed to Mohammed A Kara.

7 recordsLinked to original sources

PubMed2006

Detection and classification of the mucosal and vascular patterns (mucosal morphology) in Barrett's esophagus by using narrow band imaging.

BACKGROUND: The detection of the mucosal morphology (ie, mucosal and vascular patterns) in Barrett's esophagus (BE) by magnifying (chromo)endoscopy may improve the distinction of high-grade intraepithelial neoplasia (HGIN) from nondysplastic specialized intestinal metaplasia (SIM). Narrow band imaging (NBI) is a new technique that uses optical filters to enhance the mucosal contrast without the need for chromoendoscopy. OBJECTIVE: To use NBI for the characterization and the classification of the mucosal morphology in nondysplastic BE and in BE with HGIN. DESIGN: Descriptive study. SETTING: Single-center study in a tertiary referral center for the diagnosis and treatment of patients with BE. PATIENTS: We used NBI with magnifying endoscopy to image and biopsy randomly selected areas in 63 patients with BE. A systematic image and a biopsy specimen evaluation process was followed, including unblinded assessment of an exploratory set of images and biopsy specimens, and blinded evaluation of learning and validation sets. MAIN OUTCOME MEASUREMENTS: The relationship between the mucosal morphology and the presence of SIM and HGIN. RESULTS: SIM was characterized by either villous/gyrus-forming patterns (80%), which were mostly regular and had regular vascular patterns, or a flat mucosa with regular normal-appearing long branching vessels (20%). HGIN was characterized by 3 abnormalities: irregular/disrupted mucosal patterns, irregular vascular patterns, and abnormal blood vessels. All areas with HGIN had at least 1 abnormality, and 85% had 2 or more abnormalities. The frequency of abnormalities showed a significant rise with increasing grades of dysplasia. The magnified NBI images had a sensitivity of 94%, a specificity of 76%, a positive predictive value of 64%, and a negative predictive value of 98% for HGIN. LIMITATIONS: No data on observer agreement. CONCLUSIONS: NBI with magnification reveals the mucosal morphology characteristics of nondysplastic BE and HGIN, without the need for staining and has a relatively high diagnostic value for HGIN when used for targeted detailed examination of areas of interest.

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PubMed2006

Endoscopic video-autofluorescence imaging followed by narrow band imaging for detecting early neoplasia in Barrett's esophagus.

BACKGROUND: Video-autofluorescence imaging (AFI) and narrow band imaging (NBI) are new endoscopic techniques that may improve the detection of high-grade intraepithelial neoplasia (HGIN) in Barrett's esophagus (BE). AFI improves the detection of lesions but may give false-positive findings. NBI allows for detailed inspection of the mucosal and (micro)vascular patterns, which are related to HGIN. OBJECTIVE: A proof-of-principle study to combine AFI and NBI to improve the detection of HGIN and to reduce false-positive findings. DESIGN: Cross-sectional study of consecutive eligible patients. SETTING: Single-center. PATIENTS: Twenty patients with BE with suspected or endoscopically treated HGIN were investigated with 2 prototype imaging systems: AFI (inspection with high-resolution videoendoscopy and autofluorescence imaging for detection of lesions) and NBI (for detailed inspection of mucosal and vascular patterns of identified lesions). Lesions were sampled for histopathologic evaluation. MAIN OUTCOME MEASUREMENTS: The positive predictive value of AFI alone and of AFI-NBI for detecting HGIN and the reduction of false-positive findings because of the use of NBI. RESULTS: All of the 28 lesions with HGIN were identified with AFI. Seventeen were identified with white light (61%). Forty-seven suspicious lesions were detected with AFI: 28 contained HGIN (60%) and 19 were false positive (40%). With NBI, 25 of the true-positive lesions had definitely suspicious patterns, and 3 had dubiously suspicious patterns. Of the 19 false positives, 14 were not suspicious on NBI. The false-positive rate, therefore, was reduced from 40% to 10%. Low-grade dysplasia was found in 4 of the remaining 5 false positives. All of the 14 patients with HGIN were identified by AFI-NBI (sensitivity 100%). LIMITATIONS: Uncontrolled study in high-risk patients. CONCLUSIONS: This proof-of-principle study confirms that AFI can be used as a red-flag technique to detect suspicious lesions. With NBI, detailed inspection of the surface patterns can be performed. This combination may increase the accuracy of detecting HGIN in BE.

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PubMed2006

Stepwise radical endoscopic resection is effective for complete removal of Barrett's esophagus with early neoplasia: a prospective study.

OBJECTIVES: Endoscopic therapy for early neoplasia in Barrett's esophagus (BE) is evolving rapidly. Aim of this study was to prospectively evaluate safety and efficacy of stepwise radical endoscopic resection (ER) of BE containing early neoplasia. METHODS: Patients with early neoplasia (i.e., high-grade intraepithelial neoplasia or early cancer) in BE < or = 5 cm, without signs of submucosal infiltration or lymph node/distant metastases, were included. Patients underwent resection sessions (cap technique after submucosal lifting) with intervals of 6 wk. RESULTS: Between January 2003 and December 2004, 39 consecutive patients were included. Therapy was discontinued in two patients due to unrelated comorbidity. Complete eradication of early neoplasia was achieved in all 37 treated patients in a median number of three sessions. Complete removal of all Barrett's mucosa was achieved in 33 (89%) patients: 4 patients (all had undergone APC [argon plasma coagulation]) were found to have small isles of Barrett's mucosa underneath neosquamous mucosa. Complications occurred in two out of 88 (2%) ER procedures: one asymptomatic perforation, one delayed bleeding. Symptomatic stenosis occurred in 10 of 39 (26%) patients and was effectively treated by endoscopic bougienage. During a median follow-up of 11 months, no patients died and none had recurrence of neoplasia or Barrett's mucosa. CONCLUSIONS: Stepwise radical ER is effective for selected patients with early neoplasia in BE; provides optimal histopathological diagnosis; and may reduce recurrence rate, since all mucosa at risk is effectively removed. Use of APC should be limited to prevent buried Barrett's mucosa. Methods for prevention of stenosis should be developed.

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PubMed2005

Endoscopic video autofluorescence imaging may improve the detection of early neoplasia in patients with Barrett's esophagus.

BACKGROUND: The aim of this study was to investigate the feasibility of detecting high-grade dysplasia (HGD) and early cancer (EC) in Barrett's esophagus (BE) with a prototype video autofluorescence endoscope. METHODS: Sixty patients with BE were evaluated with a prototype, high-resolution videoendoscope that has separate charge-coupled devices for white light endoscopy (WLE) and autofluorescence imaging (AFI). Nondysplastic BE appears green on AFI, whereas potentially neoplastic areas appear blue/violet. The BE was first screened with WLE for visible abnormalities and then was examined by AFI to detect additional lesions. Lesions that raised a suspicion of neoplasia and control areas that were normal on AFI were sampled for histopathologic assessment. Finally, random 4-quadrant biopsy specimens were obtained at 2-cm intervals. RESULTS: A diagnosis of HGD/EC was made in 22 patients; one patient had no visible abnormality, and 21 had endoscopically detectable areas with HGD/EC. In 6 of the latter 21 patients, the HGD/EC was detected with AFI alone; in another patient, HGD/EC was detected with AFI and random biopsies. In 14 patients, HGD/EC was detected with both WLE and AFI; in 3 of these 14 patients, additional lesions containing HGD/EC were detected by AFI alone. CONCLUSIONS: The results of this study suggest that video AFI may improve the detection of HGD/EC in patients with BE.

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PubMed2005

A randomized crossover study comparing light-induced fluorescence endoscopy with standard videoendoscopy for the detection of early neoplasia in Barrett's esophagus.

BACKGROUND: Light-induced fluorescence endoscopy (LIFE) may improve the detection of high-grade dysplasia (HGD) and early stage cancer (EC) in Barrett's esophagus (BE). The aim of this study was to compare LIFE with standard endoscopy (SE) in a randomized crossover study. METHODS: Fifty patients with BE underwent SE and LIFE in a randomized sequence (4 to 6-week interval between procedures). The two procedures were performed by two different endoscopists who were blinded to the findings of the other examination. Targeted biopsy specimens were taken from detected lesions, followed by random biopsy specimens with a 2-cm interval, 4-quadrant protocol. Biopsy specimens were routinely evaluated and subsequently reviewed by a single, blinded expert GI pathologist. RESULTS: Targeted biopsy specimens had a sensitivity for the diagnosis of HGD/EC of 62% (8/13) for both techniques. The overall sensitivity (all biopsy specimens) was 85% for SE and 69% for LIFE (p = 0.69). All targeted biopsy specimens had a positive predictive value (PPV) for HGD/EC of 41% for SE and 28% for LIFE (p = 0.40); autofluorescence-targeted biopsy specimens had a PPV of 13%. False-positive lesions had a significantly higher rate of acute inflammation than random biopsy specimens. CONCLUSIONS: In this study, LIFE did not improve the detection of HGD or EC in patients with BE compared with SE.

Barrett Esophagus↗

PubMed2005

Endoscopic treatment of high-grade dysplasia and early stage cancer in Barrett's esophagus.

BACKGROUND: The aim of this study was to prospectively evaluate endoscopic resection (ER) combined with photodynamic therapy (PDT) for the treatment of selected patients with early neoplasia in Barrett's esophagus. METHODS: Patients with Barrett's esophagus and neoplastic lesions <2 cm in diameter and no sign of submucosal infiltration, positive lymph nodes, or distant metastasis underwent diagnostic ER (cap technique). Patients with a T1sm tumor in the resection specimen were referred for surgery; those with a T1m or a less invasive tumor underwent additional endoscopic therapy (ER, PDT, and/or argon plasma coagulation [APC]), or they were followed. PDT was performed with 5-aminolevulinic acid and a light dose of 100 J/cm 2 at lambda = 632 nm. RESULTS: Thirty-three patients underwent diagnostic ER. Endoscopic treatment was not performed in 5 patients, who underwent surgery (4 T1sm; 1, patient preference). Five patients were immediately entered into a follow-up protocol, and 23 received additional endoscopic treatment (13 additional ER, 19 PDT, 3 APC). Endoscopic treatment was successful in 26/28 patients; no severe complication was observed. During follow-up (median 19 months, range 13-24 months), 5/26 patients had a recurrence of high-grade dysplasia: all were successfully re-treated with ER. At the end of follow-up, 26/33 originally enrolled patients (79%) and 26/28 endoscopically treated patients (93%) were in local remission. CONCLUSIONS: Endoscopic therapy is safe and effective for selected patients with early stage neoplasia in Barrett's esophagus.

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PubMed2003

Follow-up for high-grade dysplasia in Barrett's esophagus.

This article will focus on the value of endoscopic follow-up for patients with high-grade dysplasia (HGD). Because the diagnosis of HGD in Barrett's esophagus is not a simple straightforward task, the article first will discuss the controversies regarding the histological diagnosis, followed by a discussion of the importance of endoscopic imaging for making the clinical diagnosis of HGD, and a systematic review of the literature relating to the presence of synchronous cancers in patients with HGD and the occurrence of cancer during endoscopic follow-up in these patients (metachronous cancers). Furthermore, the article will also discuss endoscopic techniques currently available for surveillance of these patients and make recommendations regarding surveillance intervals and the optimal biopsy protocol.

Adenocarcinoma↗