Virtual colonoscopy

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Magnetic Resonance Colonography: Comparison of Contrast-Enhanced Three-Dimensional Vibe With Two- Dimensional FISP Sequences

Journal Title, Volume, Page: 
Investigative Radiology, Volume 40, Number 2, February 2005
Year of Publication: 
2005
Authors: 
Thomas C. Lauenstein
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany
Waleed Ajaj
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany
Current Affiliation: 
Department of Medicine, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
Christiane A. Kuehle
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany
Susanne C. Goehde
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany
Thomas W. Schlosser
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany
Stefan G. Ruehm
Department of Radiology, David Geffen School of Medicine at University of California at Los Angeles
Preferred Abstract (Original): 

Purpose: The purpose of this study was to compare a dark-lumen magnetic resonance colonography (MRC) approach with a True FISP-based bright-lumen technique concerning presence of artifacts and the detection rate of colorectal pathologies.
Materials and Methods: Thirty-seven patients with suspected colorectal lesions were included in this trial. The colon was filled with 2500 mL of tap water. Two-dimensional True FISP datasets as well as T1-weighted GRE sequences (pre- and post-intravenous contrast) were acquired. The detection rate of colorectal masses and inflammatory lesions was determined for both techniques separately. Besides, image quality was assessed. All patients underwent conventional colonoscopy as the standard of reference.
Results: By means of dark-lumen MRC datasets, all polyps >5 mm were correctly diagnosed, whereas 4 polyps <5 mm were missed. Sensitivity of dark-lumen MRC amounted to 78.9%. There were no false-positive results: residual stool could correctly be differentiated from colorectal masses. The True FISP-based bright-lumen MRC, however, failed to detect 2 additional polyps resulting in a sensitivity of 68.4%. Furthermore, bright-lumen MRC led to false-positive results in 5 patients. Both techniques visualized inflammatory bowel disease in 5 patients. However, image quality of True FISP was rated superior to that of dark-lumen MRC.
Conclusion: Dark-lumen MRC proved to be superior over bright-lumen MRC regarding the detection of colorectal masses. However, True FISP imaging can turn out to be helpful as a result of high image quality and motion insensitivity.

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MR Colonography For The Assessment of Colonic Anastomoses

Journal Title, Volume, Page: 
Journal of Magnetic Resonance Imaging Volume 24, Issue 1, pages 101–107, July 2006
Year of Publication: 
2006
Authors: 
Waleed Ajaj
Medical Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany
Current Affiliation: 
Department of Medicine, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
Mathias Goyen
Medical Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany
Jost Langhorst
Department of Internal Medicine, Kliniken Essen-Mitte, Essen, Germany
Stefan G. Ruehm
Department of Radiology, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California, USA
Guido Gerken
Department of Gastroenterology and Hepatology, University Hospital Essen, Essen, Germany
Thomas C. Lauenstein
Department of Radiology, Emory Clinic, Atlanta, Georgia, US
Preferred Abstract (Original): 

Purpose: To assess colonic anastomoses in patients after surgical treatment by means of MR colonography (MRC) in comparison with conventional colonoscopy (CC).
Materials and Methods: A total of 39 patients who had previously undergone colonic resection and end-to-endanastomosis were included in the study. MRI was based on a dark-lumen approach. Contrast-enhanced T1-weighted (T1w) three-dimensional (3D) images were collected following the rectal administration of water for colonic distension. The MRC data were evaluated by two radiologists. The criteria employed to evaluate the anastomoses included bowel wall thickening and increased contrast uptake in this region. Furthermore, all other colonic segments were assessed for the presence of pathologies.
Results: In 23 and 20 patients the anastomosis was rated to be normal by MRC and CC, respectively. In three patients CC revealed a slight inflammation of the anastomosis that was missed by MRI. A moderate stenosis of the anastomosis without inflammation was detected by MRC in five patients, which was confirmed by CC. In the remaining 11 patients a relevant pathology of the anastomosis was diagnosed by both MRC and CC. Recurrent tumor was diagnosed in two patients with a history of colorectal carcinoma. In the other nine patients inflammation of the anastomosis was seen in seven with Crohn’s disease (CD) and two with ulcerative colitis. MRC did not yield any falsepositive findings, resulting in an overall sensitivity/specificity for the assessment of the anastomosis of 84%/100%.
Conclusion: MRC represents a promising alternative to CC for the assessment of colonic anastomoses in patients with previous colonic resection.

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Utility of Dark-Lumen MR Colonography For The Assessment of Extra-Colonic Organs

Journal Title, Volume, Page: 
Eur Radiol (2007) 17: 1574–1583
Year of Publication: 
2007
Authors: 
Waleed Ajaj
Medical Center, University Hospital Hamburg-Eppendorf, Martini-Straße 52, 22046, Hamburg, Germany
Current Affiliation: 
Department of Medicine, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
Stefan G. Ruehm
David Geffen School of Medicine, Department of Radiology, University of California-Los Angeles, Los Angeles, USA
Susanne C. Ladd
Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany
Guido Gerken
Department of Gastroenterology and Hepatology, University Hospital Essen, Essen, Germany
Mathias Goyen
Medical Center, University Hospital Hamburg-Eppendorf, Martini-Straße 52, 22046, Hamburg, Germany
Preferred Abstract (Original): 

The aim of the study was to evaluate the utility of dark-lumen MR colonography (MRC) for the assessment of extra-colonic organs. Three hundred seventy-five subjects with suspected colonic disease underwent a complete MRC examination. MRC data were evaluated by two radiologists in a blinded fashion. In addition to the large bowel, the extra-intestinal organs from the lung bases to the pelvis were assessed for the presence of pathologies. All findings were divided into known or unknown findings and therapeutically relevant or irrelevant findings. If deemed necessary, other diagnostic imaging tests to further assess those findings were performed. In total, 510 extracolonic findings were found in 260 (69%) of the 375 subjects. Known extra-colonic findings were found in 140 subjects (54%) and unknown findings in 120 subjects (46%). Thirty-one (12%) of the 260 subjects had therapeutically relevant findings (45 findings); 229 patients (88%) had irrelevant findings (465 findings). Dark-lumen MRC is a useful tool not only for the assessment of the entire colon, but also for the evaluation of extra-colonic organs. Thus, intra- and extra-colonic pathologies can be diagnosed within the same examination.

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