Low-dose multidetector-row CT angiography of the infra-renal aorta and lower extremity vessels: image quality and diagnostic accuracy in comparison with standard DSA.

To investigate the possibility of reducing X-ray exposure during multidetector-row spiral computed tomographic (MDCT) angiography and to compare the image quality and diagnostic accuracy of different dosages with digital subtraction angiography (DSA) in the evaluation of the infra-renal aorta and lower extremities vessels. Seventy-five patients, randomly divided into three groups of 25 patients each, were evaluated for atherosclerotic disease with four-row spiral CT angiography (4x2.5 mm) and DSA. MDCT scanning parameters were kept constant, except for milliamperage (mAs): group A: 50 mAs; group B: 100 mAs; group C: 130 mAs. Images were analysed by two vascular radiologists in consensus. DSA represented the standard of reference. The diagnostic value of MDCT and total radiation exposure were evaluated for each data set. The simulated effective dose was 3.7 mSv for 50 mAs, 8.2 mSv for 100 mAs and 13.7 mSv for 130 mAs for men, and 4 mSv for 50 mAs, 8.9 mSv for 100 mAs and 14.8 mSv for 130 mAs for women. The dose reduction was 74% for group A and 40% for group B. The evaluation of the presence and degree of stenoses revealed a sensitivity, specificity, accuracy, PPV and NPV of 96%, 94%, 95%, 83% and 99% for Group A (50 mAs), 96%, 96%, 96%, 89% and 99% for Group B (100 mAs) and 98%, 96%, 97%, 91% and 100% for the standard dose protocol, Group C (130 mAs). Low-dose scanning is thus a feasible and accurate option for four-row CT angiography of the peripheral vessels. This technique provides substantial reduction of the radiation dose delivered to the patient while maintaining optimal diagnostic accuracy.

CE-Magnetic Resonance Mammography for the evaluation of the contralateral breast in patients with diagnosed breast cancer.

PURPOSE: To evaluate the role of contrast-enhanced Magnetic Resonance Mammography (MRM) in the evaluation of the contralateral breast in patients with recently diagnosed breast cancer. MATERIALS AND METHODS: Fifty patients with proved unilateral breast cancer, with a negative contralateral breast at physical examination, ultrasound and mammography, were studied with a 1.5 T magnet (Siemens, Vision Plus, Germany). A bilateral breast surface coil was used. Dynamic 3D Flash T1-weighted sequences were acquired in the axial plane before and 0, 2, 4, 6 and 8 minutes after the administration of 0.1 mmol/kg of Gd-BOPTA at a flow rate of 2 ml/s followed by 10 ml of saline. The level of suspicion was reported on a scale from 0 to 5 following the BI-RADS classification, based on lesion morphology and kinetic features. The results were compared with the histological findings after biopsy or surgery. RESULTS: Fourteen out of 50 patients (28%) had contralateral lesions identified on MRM. Biopsy was performed in four of them for suspicious lesions (BI-RADS 4) while 10 patients underwent surgery because of highly suggestive malignant lesions (BI-RADS 5). Histology diagnosed three fibroadenomas, 5 ductal carcinomas in situ, 2 lobular carcinomas in situ, 3 invasive ductal carcinomas and 1 invasive lobular carcinoma. Contrast-enhanced MRM yielded no false negative and three false positives. CONCLUSIONS: Our results demonstrate a very good accuracy of Magnetic Resonance Mammography in the detection of synchronous contralateral cancer in patients with newly diagnosed breast cancer. Therefore, contrast-enhanced MRM could be introduced to screen patients with proven breast cancer before they undergo surgery.

Breast lesion detection and characterization at contrast-enhanced MR mammography: gadobenate dimeglumine versus gadopentetate dimeglumine.

PURPOSE: To prospectively and intraindividually compare equivalent (0.1 mmol per kilogram of body weight) doses of gadobenate dimeglumine and gadopentetate dimeglumine for accuracy of detection and characterization of breast lesions at contrast material-enhanced magnetic resonance (MR) mammography. MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Twenty-six consecutive women (mean age, 47.8 years) suspected of having a breast tumor at mammography and sonography underwent two identical MR examinations at 1.5 T; examinations were separated by more than 48 hours but less than 72 hours. A T1-weighted three-dimensional gradient-echo sequence was used, and images were acquired before and at 0, 2, 4, 6, and 8 minutes after randomized injection of gadopentetate dimeglumine or gadobenate dimeglumine at an identical flow rate of 2 mL/sec. Separate and combined assessment of unenhanced, contrast-enhanced, and subtracted images was performed blindly by two readers in consensus. Accuracy for lesion detection was determined against a final diagnosis based on findings at conventional mammography, sonography, and surgery. Sensitivity, specificity, positive and negative predictive values, and overall accuracy for malignant lesion identification were determined against histologic results. Data were analyzed with the McNemar test, proportional odds models, and analysis of variance. RESULTS: MR mammography with gadobenate dimeglumine depicted significantly (P = .003) more lesions (45 of 46) than did that with gadopentetate dimeglumine (36 of 46), and detected lesions were significantly (P < .001) more conspicuous with gadobenate dimeglumine. Confidence for characterization was significantly (P = .031) greater with gadobenate dimeglumine. Comparison of the contrast agents for their ability to help identify malignant lesions revealed significant (P = .02) superiority for gadobenate dimeglumine: Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for malignant lesion identification were, respectively, 94.7%, 100%, 100%, 80.0%, and 95.6% with gadobenate dimeglumine and 76.3%, 100%, 100%, 47.1%, and 80.4% with gadopentetate dimeglumine. Quantitative evaluation of signal intensity-time curves revealed significantly (P < .001) greater lesion enhancement with gadobenate dimeglumine. CONCLUSION: Detection of breast lesions and accurate identification of malignant lesions at MR imaging are significantly superior with gadobenate dimeglumine in comparison with gadopentetate dimeglumine.

Color-coded automated signal intensity curves for detection and characterization of breast lesions: preliminary evaluation of a new software package for integrated magnetic resonance-based breast imaging.

OBJECTIVES: The objective of this study was to evaluate the value of a color-coded automated signal intensity curve software package for contrast-enhanced magnetic resonance mammography (CE-MRM) in patients with suspected breast cancer. MATERIALS AND METHODS: Thirty-six women with suspected breast cancer based on mammographic and sonographic examinations were preoperatively evaluated on CE-MRM. CE-MRM was performed on a 1.5-T magnet using a 2D Flash dynamic T1-weighted sequence. A dosage of 0.1 mmol/kg of Gd-BOPTA was administered at a flow rate of 2 mL/s followed by 10 mL of saline. Images were analyzed with the new software package and separately with a standard display method. Statistical comparison was performed of the confidence for lesion detection and characterization with the 2 methods and of the diagnostic accuracy for characterization compared with histopathologic findings. RESULTS: At pathology, 54 malignant lesions and 14 benign lesions were evaluated. All 68 (100%) lesions were detected with both methods and good correlation with histopathologic specimens was obtained. Confidence for both detection and characterization was significantly (P < or = 0.025) better with the color-coded method, although no difference (P > 0.05) between the methods was noted in terms of the sensitivity, specificity, and overall accuracy for lesion characterization. Excellent agreement between the 2 methods was noted for both the determination of lesion size (kappa = 0.77) and determination of SI/T curves (kappa = 0.85). CONCLUSIONS: The novel color-coded signal intensity curve software allows lesions to be visualized as false color maps that correspond to conventional signal intensity time curves. Detection and characterization of breast lesions with this method is quick and easily interpretable.

Radial scars of the breast: contrast-enhanced magnetic resonance mammography appearance.

The purpose of this study was to evaluate the appearance of contrast-enhanced magnetic resonance mammography (CE-MRM) in patients with suspected radial scar on mammography. Thirty women with radial opacities or black star findings at mammography, preoperatively underwent CE-MRM. Examinations were performed with a 1.5 T magnet with a bilateral surface coil using a FS T2-weighted turbo spin echo (TSE) and three-dimensional (3D) dynamic T1-weighted fast low-angle shot (FLASH) sequences. Criteria for lesion evaluation included morphologic patterns and signal intensity curves. Mammography and CE-MRM findings were compared with pathologic findings. CE-MRM suggested the presence of radial scar in 18 of 30 cases and the presence of malignancy in 11 of 30 cases; 1 lesion was classified as borderline. At surgery 22 radial scars (including 4 with associated ductal carcinoma in situ) and 8 carcinomas were detected. CE-MRM provided a specificity of 89%, sensitivity of 83%, and accuracy of 87%. Differently from breast cancer, radial scars are nonenhancing at CE-MRM. Nevertheless, the possibility of nonenhancing carcinomatous foci existing within radial scars implies that surgical excision should be performed in all cases.

Laparoscopic splenectomy: multi-detector row CT for preoperative evaluation.

PURPOSE: To prospectively evaluate multi-detector row spiral computed tomography (CT) for determination of splenic volume, splenic vascular anatomy, and presence of accessory spleens and parenchymal lesions in patients who were undergoing laparoscopic splenectomy. MATERIALS AND METHODS: Twenty-two patients who were candidates for laparoscopic splenectomy underwent multiphasic multi-detector row CT. Two observers evaluated splenic volume with two hand-tracing editing modalities. Variability between the two observers was calculated with a reliability coefficient (Cronbach alpha). A linear regression equation for each modality was generated to identify the correlation between the two observers. Multi-detector row CT angiography was evaluated for assessment of splenic vascular anatomy. Presence and number of both accessory spleens and parenchymal lesions were recorded. RESULTS: Mean splenic volume was 1,050 and 1,046 mL, respectively, for observers A and B by using each-section editing (technique 1) and 1,067 and 1,068 mL for observers A and B by using distanced editing (technique 2). For each editing modality, alpha reliability coefficient was higher than 0.99. Both techniques 1 and 2 were very highly predictive of specimen weight and had R2 values of greater than 0.99 (P <.001). CT angiograms correctly showed polar arteries in all cases and the presence of the arteria pancreatica magna in one case. Multi-detector row CT demonstrated the presence, number, and size of all accessory spleens and of focal parenchymal lesions. CONCLUSION: Multi-detector row CT volumetric and anatomic evaluation provided accurate and reproducible information.

Gadobenate dimeglumine (Gd-DTPA) vs gadopentetate dimeglumine (Gd-BOPTA) for contrast-enhanced magnetic resonance angiography (MRA): improvement in intravascular signal intensity and contrast to noise ratio.

PURPOSE: The purpose of this study was to compare contrast enhanced MR angiography (MRA) with gadopentetate dimeglumine (Gd-DTPA) to MRA with gadobenate dimeglumine (Gd-BOPTA), a high relaxivity paramagnetic contrast agent. MATERIALS AND METHODS: Twelve patients referred for carotid artery stenosis were examined with MR angiography using a fast spoiled gradient echo sequence. Gd-DTPA and Gd-BOPTA enhanced MR angiography were performed within 48-72 hours using a dose of 0.1 mmol/kg for Gd-BOPTA and 0.2 mmol/kg for Gd-DTPA, at a flow rate of 2 ml/s. Images were evaluated by two blinded radiologists. Qualitative and quantitative evaluations were performed comparing the sets of images from the two examinations. RESULTS: Qualitative evaluation demonstrated superior arterial contrast enhancement and vessel conspicuity with Gd-BOPTA compared with Gd-DTPA. Quantita-tive evaluation showed an improvement in both signal intensity and contrast to noise ratio with Gd-BOPTA. CONCLUSION: The greater relaxivity of Gd-BOPTA, at lower doses, compared with Gd-DTPA, provides higher intravascular signal and signal to noise ratio. Gd-BOPTA appears to be an optimal contrast agent for contrast enhanced MRA.