Air-inflated magnetic resonance colonography in patients with incomplete conventional colonoscopy: Comparison with intraoperative findings, pathology specimens, and follow-up conventional colonoscopy.

BACKGROUND: To assess the usefulness of air-inflated magnetic resonance colonography (MRC) in patients with incomplete conventional colonoscopy (CC). METHODS: From September 2001 to December 2004, 51 patients (25 male and 26 female, age range 32 to 85 years) with incomplete colonoscopy were recruited to have MRC performed. Half-fourier single short turbo spin echo (HASTE) axial, coronal, and three dimensional fat suppressed gradient echo sequence (VIBE) coronal images in both the prone and supine positions were performed for each patient. MRC was reviewed by two radiologists for detection of synchronous colonic lesion. The location and size of lesions were recorded and were compared with the findings of CC. Patients were managed according to the clinical situation and intraoperative findings were compared with MRC findings. Follow-up colonoscopy was performed in 29 patients. The follow-up colonoscopy findings were then compared with the MRC findings. RESULTS: Forty-four patients had incomplete colonoscopy because of an obstructing tumor. The other seven patients had incomplete colonoscopy because of excessive bowel looping. Apart from one patient suffering from chronic obstructive airway disease with resulting nondiagnostic MRC, all other patients had MRC successfully performed. Each colon was divided into six bowel segments for analysis. All 300 segments were of diagnostic quality and were assessed by the MRC. MRC correctly identified all 44 obstructing tumors demonstrated by initial CC. Synchronous tumors in proximal colonic segments were identified in two patients by MRC. In addition, MRC identified two colonic tumors located in bowel segments inaccessible by CC because of excessive looping. CONCLUSIONS: MRC is useful for detection of colonic pathology and assessment of proximal colon in patients with colonic cancer after incomplete colonoscopy.

Magnetic resonance angiography of coronary arteries with a 3-dimensional magnetization-prepared true fast imaging with steady-state precession sequence compared with conventional coronary angiography.

BACKGROUND: The aim of the study was to compare the detection of clinically significant coronary artery stenosis using a magnetic resonance 3-dimensional (3D) breath-hold true fast imaging with steady-state precession (trueFISP) sequence with conventional coronary angiography. METHODS: Twenty-nine patients who were scheduled to undergo or had recently undergone diagnostic conventional coronary angiogram participated in this study. The left main, left anterior descending, left circumflex, and right coronary arteries were studied using the 3D breath-hold trueFISP technique. Each artery was imaged with 1 acquisition in 16 to 32 heartbeats. The image quality, vessel length, and presence or absence of stenosis were evaluated. A score of 1 to 3 (1 = noninterpretable, 2 = good, 3 = excellent) was used to assess image quality. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of magnetic resonance angiography in detecting significant coronary artery stenosis (> 50% luminal narrowing) on conventional coronary angiogram were calculated. RESULTS: Of 116 vessels, 108 were assessed in 29 patients. Twenty vessels that had image quality score of 1 were excluded from further evaluation. The mean lengths of vessels visualized were the following: left anterior descending 3.6 cm, left circumflex 3.4 cm, and right coronary 6.6 cm. The entire length of the left main coronary artery was visualized. For the visualized arterial segments, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for detecting significant coronary artery stenosis were 92.8%, 95.3%, 95.0%, 68.4%, and 99.2%, respectively. CONCLUSIONS: The 3D breath-hold trueFISP technique, which uses the endogenous contrast of blood, is potentially useful in ruling out significant coronary artery stenosis but not yet sensitive enough as a screening tool.

Assessment of hyperacute stroke like symptoms by diffusion-weighted images.

We assessed the role of diffusion-weighted images in the evaluation of hyperacute stroke like symptoms in 18 patients. The volume of infarct measured by diffusion-weighted imaging (DWI) was correlated with the later computed tomography (CT) examinations. DWI had a sensitivity of 92%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 86% in detection of acute hemorrhagic and ischemic stroke. There is a good correlation with the volume of infarct measured by DWI and follow-up CT with a P < .05.