Detection of head and neck squamous cell carcinoma with diffusion weighted MRI after (chemo)radiotherapy: correlation between radiologic and histopathologic findings.

PURPOSE: To investigate the value of diffusion weighted magnetic resonance imaging (DW-MRI) in differentiating persistent or recurrent head and neck squamous cell carcinoma (HNSCC) from nontumoral postradiotherapeutic alterations. METHODS AND MATERIALS: In 26 patients with suspicion of persistent or recurrent HNSCC, MRI of the head and neck was performed, including routine turbo spin-echo (TSE) sequences and an additional echo-planar DW-MRI sequence, using a large range of b-values (0-1000 s/mm(2)). Apparent diffusion coefficient (ADC) maps were calculated. In the suspect areas at the primary site and in the suspect lymph nodes, signal intensity was measured on the native b0 and b1000 images and ADC values were calculated for these tissues. The same was done for surrounding irradiated normal tissue. Imaging results were correlated to histopathology. RESULTS: Signal intensity on native b0 images was significantly lower for HNSCC than for nontumoral postradiotherapeutic tissue (p < 0.0001), resulting in a sensitivity of 66.2%, specificity of 60.8%, and accuracy of 62.4%. Signal intensity on native b1000 images was significantly higher for HNSCC than for nontumoral tissue (p < 0.0001), resulting in a sensitivity of 71.6%, specificity of 71.3%, and accuracy of 71.4%. ADC values were significantly lower for HNSCC than for nontumoral tissue (p < 0.0001), resulting in a sensitivity of 94.6%, specificity of 95.9%, and accuracy of 95.5%. When compared with computed tomography, TSE-MRI and fluorodeoxyglucose-positron emission tomography, DW-MRI yielded fewer false-positive results in persistent primary site abnormalities and in persistent adenopathies, and aided in the detection of subcentimetric nodal metastases. CONCLUSIONS: Diffusion weighted-MRI accurately differentiates persistent or recurrent HNSCC from nontumoral tissue changes after (chemo)radiotherapy.

Validation and application of single breath-hold cine cardiac MR for ventricular function assessment in children with congenital heart disease at rest and during adenosine stress.

PURPOSE: To validate the accuracy of ventricular function analysis using a single breath-hold real-time steady sate free precession (SSFP) cine MR method and demonstrate its application during adenosine stress imaging in children with congenital heart disease. MATERIALS AND METHODS: Twenty-eight subjects with congenital heart disease were studied (mean age 12.4 +/- 2.3 years) with MR imaging at 1.5 T. Short-axis images covering the entirety of both ventricles were acquired at rest, with a conventional segmented SSFP cine sequence acquired over multiple breath-holds and a single breath-hold real-time SSFP sequence. Seventeen subjects were given an infusion of adenosine, and the single breath-hold real-time short-axis stack was repeated during stress. Two independent observers performed the ventricular function analysis. Data was compared between the 2 acquisition methods at rest and between the single breath-hold acquisition at rest and during adenosine stress. RESULTS: There was good agreement between the multiple breath-hold and single breath-hold methods for measurement of end-diastolic volume (r = 0.95 and 0.96, p < .0001) and end-systolic volume (ESV) (r = 0.76 and 0.90, p < .0001) for the left and right ventricles respectively, and the left ventricular mass (r = 0.97, p < .0001). Adenosine was administered safely to all subjects. During stress there were significant changes in the heart rate and ESV, which led to a significant increase in cardiac output (mean 1.5 +/- 1.0 L/min, p < .001). CONCLUSION: Single breath-hold real-time SSFP cine imaging is robust and accurate in assessing cardiac function in children with congenital heart disease. An application of this method is the rapid assessment of cardiac function during adenosine stress.

MR coronary angiography and late-enhancement myocardial MR in children who underwent arterial switch surgery for transposition of great arteries.

PURPOSE: To prospectively evaluate the feasibility of magnetic resonance (MR) coronary artery imaging and to define myocardial damage with late-enhancement myocardial MR imaging in children who underwent arterial switch surgery for transposition of the great arteries. MATERIALS AND METHODS: The local research ethics committee approved this study, and the subjects and/or a parent or guardian gave informed consent. Sixteen asymptomatic subjects who had undergone arterial switch surgery for transposition of the great arteries were studied (mean age, 10.8 years +/- 1.3; 11 male subjects, five female subjects). MR coronary angiography, late-enhancement MR imaging, global ventricular function, and regional wall motion were assessed. Fifteen children were awake during imaging; one was imaged with the use of general anesthetic. RESULTS: In 23 (72%) of 32 coronary arteries imaged, diagnostic-quality images of the coronary ostium and proximal coronary artery course were acquired; this increased to 100% in subjects older than 11 years. No coronary ostial stenoses were seen. In all subjects, the proximal course of the coronary arteries was visualized. Two subendocardial viability defects were detected, which corresponded to known compromise of the artery that supplied that territory at the time of surgery. Global left and right ventricular function were preserved, with no regional wall abnormalities. CONCLUSION: Diagnostic-quality MR coronary angiography is feasible in subjects who have undergone arterial switch surgery for transposition of the great arteries, with no unexpected areas of myocardial infarction detected.

High-spatial-resolution 3D balanced turbo field-echo technique for MR angiography of the renal arteries: initial experience.

PURPOSE: To compare a multislab balanced turbo field-echo magnetic resonance (MR) angiographic technique, without the use of a contrast agent, with digital subtraction angiography (DSA) for imaging of the renal arteries. MATERIALS AND METHODS: Twenty-five randomly selected patients (eight women and 17 men; age range, 27-88 years; mean age, 72 years) suspected of having renal artery stenosis underwent both DSA and balanced turbo field-echo MR angiography. A consensus result was obtained among three radiologists in evaluation of main renal arteries on balanced turbo field-echo images and DSA images. Sensitivity, specificity, and negative and positive predictive values of the balanced turbo field-echo technique were calculated, and receiver operating characteristic analysis was performed for depiction of hemodynamically significant stenosis. Cohen kappa analysis was used to assess agreement between the two imaging methods in grading of stenoses and depiction of significant stenosis. Accessory renal arteries also were evaluated. RESULTS: Fifty main renal arteries and 11 accessory arteries were fully depicted with DSA. DSA depicted 11 stenotic lesions in the main renal arteries. In comparison, balanced turbo field-echo MR angiography enabled visualization of 46 of 50 main renal arteries to their first branching points and depicted 10 of 11 accessory arteries. Sensitivity, specificity, negative predictive value, and positive predictive value of this technique for depiction of significant stenosis were 100% (four of four), 98% (41 of 42), 100% (41 of 41), and 80% (four of five), respectively. The area under the receiver operating characteristic curve was 0.988. kappa was 0.782 for grading of stenoses and 0.877 for depiction of significant stenosis. CONCLUSION: Multislab balanced turbo field-echo imaging has potential as an MR angiography technique for depiction of normal and diseased renal arteries.