Jos M. A. van Engelshoven

USPIO-enhanced MR Imaging for Nodal Staging in Patients with Primary Rectal Cancer: Predictive Criteria

PURPOSE To prospectively determine diagnostic performance of predictive criteria for nodal staging with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance (MR) imaging in primary rectal cancer patients, with histopathologic findings as reference standard. MATERIALS AND METHODS Institutional review board approval and informed consent were obtained. Twenty-eight rectal cancer patients (18 men, 10 women; mean age, 68 years) underwent USPIO-enhanced MR. Two observers with different experience evaluated each node on three-dimensional T2*-weighted images for border irregularity, short- and long-axis diameter, and estimated percentage (<30%, 30%-50%, or >50%) of white region within the node. Ratio of measured surface area of white region within the node to measured surface area of total node (ratio(A)) was calculated. Signal intensity (SI) of gluteus muscle (SI(GM)), total node (SI(TN)), and white (SI(WR)) and dark (SI(DR)) regions within the node were used to calculate SI(TN)/SI(GM) and SI(WR)/SI(DR) ratios. Lesion-by-lesion, receiver operating characteristic curve, and interobserver agreement analyses were performed. The most accurate and practical criterion was evaluated by observer 3. RESULTS In 28 patients, 236 lymph nodes were examined. Area under the receiver operating characteristic curve (AUC) of estimated percentage of white region and ratio(A) were 0.96 and 0.99 (observer 1) and 0.95 and 0.97 (observer 2), respectively. AUC of estimated percentage criterion for observer 3 was 0.96. AUC of border, short- and long-axis diameter, and SI(TN)/SI(GM) and SI(WR)/SI(DR) ratios were 0.65, 0.75, 0.79, 0.85, and 0.75 (observer 1) and 0.58, 0.75, 0.79, 0.89, and 0.79 (observer 2), respectively. Interobserver agreement (kappa value) for estimated white region between observers 1 and 2, 1 and 3, and 2 and 3 were 0.77, 0.79, and 0.84, respectively. For observers 1 and 2, kappa value for border was 0.28. For observers 1 and 2, intraclass correlation coefficient for short- and long-axis diameters, ratio(A), and SI(TN)/SI(GM) and SI(WR)/SI(DR) ratios were 0.91, 0.96, 0.91, 0.72, and 0.92, respectively. CONCLUSION Estimated percentage of white region and measured ratio(A) are the most accurate criteria for predicting malignant nodes with USPIO-enhanced MR imaging; the first criterion is the most practical.

In vivo detection of hemorrhage in human atherosclerotic plaques with magnetic resonance imaging

To investigate the performance of high‐resolution T1‐weighted (T1w) turbo field echo (TFE) magnetic resonance imaging (MRI) for the identification of the high‐risk component intraplaque hemorrhage, which is described in the literature as a troublesome component to detect.

Motion of the distal renal artery during three-dimensional contrast-enhanced breath-hold MRA.

To study the potential detrimental effects of renal motion on breath‐hold three‐dimensional contrast‐enhanced (CE) magnetic resonance angiography (MRA).

Locally advanced rectal cancer: MR imaging for restaging after neoadjuvant radiation therapy with concomitant chemotherapy. Part II. What are the criteria to predict involved lymph nodes?

PURPOSE To prospectively determine diagnostic performance of predictive criteria for nodal restaging after radiation therapy with concomitant chemotherapy by using ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance (MR) imaging in patients with rectal cancer. MATERIALS AND METHODS After institutional review board approval and informed consent were obtained, 39 patients (24 men, 15 women; mean age, 64 years) with rectal cancer underwent USPIO-enhanced two-dimensional (2D) T2-weighted fast spin-echo, three-dimensional (3D) T1-weighted gradient-echo, and 3D T2*-weighted MR for restaging. Two observers evaluated nodes for border irregularity, short- and long-axis diameters, and estimated percentage of white region (<30%, 30%-50%, or >50%) within the node (3D T2*-weighted images). Ratio of the measured surface area of the white region within the black node to the measured surface area of the total node (Ratio(A)) was calculated. Signal intensity (SI) in gluteus muscle (SI(GM)) and in total node (SI(TN)) were used to calculate SI(TN)/SI(GM) ratio. Histopathologic findings were reference standard. Receiver operating characteristic (ROC) curves were compared and interobserver agreement was determined. RESULTS Lesion-by-lesion analysis was feasible in 201 lymph nodes. Area under the ROC curve (AUC) of border and short- and long-axis diameters for observer 1 were 0.85, 0.87, and 0.88 and for observer 2 were 0.70, 0.89, and 0.87, respectively. AUC for estimated percentage of white region within the node, Ratio(A), and SI(TN)/SI(GM) ratio for observer 1 were 0.98, 0.99, and 0.62 and for observer 2 were 0.97, 0.98, and 0.65, respectively. AUC for USPIO-enhanced MR criteria was significantly better than AUC for conventional MR criteria (P < .01). All criteria except border irregularity and SI(TN)/SI(GM) ratio showed high interobserver agreement (kappa > 0.79). CONCLUSION The most reliable predictors for identifying benign nodes after radiation therapy with concomitant chemotherapy by using USPIO-enhanced MR imaging for restaging in patients with rectal cancer were estimated percentage of white region within the node and Ratio(A). Measurements on standard 2D T2-weighted fast spin-echo images versus primary staging results offer reasonably good accuracy to identify benign lymph nodes after therapy.

Preoperative estimation of the pathological breast tumour size by physical examination, mammography and ultrasound: a prospective study on 105 invasive tumours.

OBJECTIVE The clinical breast tumour size can be assessed preoperatively by physical examination, mammography and ultrasound. At present it is not clear which modality correlates best with the histological invasive breast tumour size. This prospective study aims to determine the most accurate clinical method (physical examination, mammography or ultrasound) to predict the histological invasive tumour size preoperatively. METHODS AND PATIENTS Between October 1999 and August 2000, 96 women with 105 invasive malignant breast tumours were included in this study. All patients underwent excision and the tumour size was measured on histology. Tumour size was measured by all three modalities in 73 cases. Results were evaluated by calculating correlation coefficients. The examination modalities presenting the best estimation of the pathological tumour size were used in a stepwise linear regression analysis to construct a formula predicting the pathological tumour size from the result of the various diagnostic modalities. RESULTS The correlation coefficient between ultrasound and pathological size (r=0.68) was significantly better than the correlations between physical examination and pathological size (r=0.42) and mammographic and pathological size (r=0.44). Physical examination overestimates and ultrasound underestimates breast tumour classification. The most accurate prediction formula was: Pathological tumour size (mm) equals sonographic tumour size (mm)+3 mm. CONCLUSION When comparing physical examination, mammography and ultrasound for the prediction of the pathological size of a malignant breast tumour, ultrasound is the best predictor. The ensuing regression formula determines pathological size as tumour size by ultrasound+3 mm. However, with the wide 95% confidence interval of +/-11 mm, it remains difficult to predict the exact pathological size for an individual invasive breast tumour. A small deviation in millimetres of the tumour size could lead to a change in treatment and to another prognostic estimate.

Multicenter randomized controlled trial of the costs and effects of noninvasive diagnostic imaging in patients with peripheral arterial disease: The DIPAD trial

OBJECTIVE The purpose of our study was to compare the costs and effects of three noninvasive imaging tests as the initial imaging test in the diagnostic workup of patients with peripheral arterial disease. MATERIALS AND METHODS Of 984 patients assessed for eligibility, 514 patients with peripheral arterial disease were randomized to MR angiography (MRA) or duplex sonography in three hospitals and to MRA or CT angiography (CTA) in one hospital. The outcome measures included the clinical utility, functional patient outcomes, quality of life, and actual diagnostic and therapeutic costs related to the initial imaging test during 6 months of follow-up. RESULTS With adjustment for potentially predictive baseline variables, the learning curve, and hospital setting, a significantly higher confidence and less additional imaging were found for MRA and CTA compared with duplex sonography. No statistically significant differences were found in improvement in functional patient outcomes and quality of life among the groups. The total costs were significantly higher for MRA and duplex sonography than for CTA. CONCLUSION The results suggest that both CTA and MRA are clinically more useful than duplex sonography and that CTA leads to cost savings compared with both MRA and duplex sonography in the initial imaging evaluation of peripheral arterial disease.

Contrast‐enhanced peripheral MR angiography using SENSE in multiple stations: Feasibility study

To investigate if the use of parallel imaging is feasible and beneficial for peripheral contrast‐enhanced magnetic resonance angiography (CE‐MRA).

Contrast‐enhanced peripheral MR angiography at 3.0 Tesla: Initial experience with a whole‐body scanner in healthy volunteers

To report preliminary experience with contrast‐enhanced magnetic resonance angiography (CE‐MRA) of the peripheral arteries on a 3.0 T whole‐body scanner equipped with a prototype body coil.

Multimodality Imaging of Carotid Artery Plaques 18F-Fluoro-2-Deoxyglucose Positron Emission Tomography, Computed Tomography, and Magnetic Resonance Imaging

Background and Purpose— This study’s objective was to compare 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET), CT, and MRI of carotid plaque assessment. Materials and Methods— Fifty patients with symptomatic carotid atherosclerosis underwent 18F-FDG PET/CT and MRI. Correlations and agreement between imaging findings were assessed by Spearman and Pearson rank correlation tests, t tests, and Bland-Altman plots. Results— Spearman &rgr; between plaque 18F-FDG standard uptake values and CT/MRI findings varied from −0.088 to 0.385. Maximum standard uptake value was significantly larger in plaques with intraplaque hemorrhage (1.56 vs 1.47; P=0.032). Standard uptake values did not significantly differ between plaques with an intact and thick fibrous cap and plaques with a thin or ruptured fibrous cap on MRI. (1.21 vs 1.23; P=0.323; and 1.45 vs 1.54; P=0.727). Pearson &rgr; between CT and MRI measurements varied from 0.554 to 0.794 (P<0.001). For lipid-rich necrotic core volume, the CT–MRI correlation was stronger in mildly (≤10%) than in severely (>10%) calcified plaques (Pearson &rgr; 0.730 vs 0.475). Mean difference in measurement ±95% limits of agreement between CT and MRI for minimum lumen area, volumes of vessel wall, lipid-rich necrotic core, calcifications, and fibrous tissue were 0.4±18.1 mm2 (P=0.744), −41.9 ±761.7 mm3 (P=0.450), 78.4±305.0 mm3 (P<0.001), 180.5±625.7 mm3 (P=0.001), and −296.0±415.8 mm3 (P<0.001), respectively. Conclusions— Overall, correlations between 18F-FDG PET and CT/MRI findings are weak. Correlations between CT and MRI measurements are moderate to strong, but there is considerable variation in absolute differences.

CT lung densitometry: dependence of CT number histograms on sample volume and consequences for scan protocol comparability.

PURPOSE Our goals were to determine the dependence of CT number histograms of the lung on section thickness and reconstruction filter and to evaluate the consequences for scan protocol conformity required for universally comparable densitometry of the lungs. METHOD The effects of section thickness and reconstruction filter were parameterized with the CTs sample volume [V approximately (section thickness x in-plane resolution2)]. In a study of 31 patients, we determined as a function of V the following CT number histogram parameters: percentiles P(10) and P(90), pixel indexes PI(-905) and PI(-950), and standard deviation. RESULTS Patient histogram parameters depended strongly on sample volume. Large differences were found between protocols using 1 and 10 mm sections. For small variations in somewhat larger sample volumes (> 8 mm3), discrepancies were much smaller. CONCLUSION To obtain comparable histogram parameters, nearly identical sample volumes (> or = 8 mm3) should be used. When this condition is satisfied, available data suggest that universally comparable densitometry is feasible.