Reduction in respiratory motion artefacts on gadoxetate-enhanced MRI after training technicians to apply a simple and more patient-adapted breathing command.

OBJECTIVE: To investigate whether a trained group of technicians using a modified breathing command during gadoxetate-enhanced liver MRI reduces respiratory motion artefacts compared to non-trained technicians using a traditional breathing command. MATERIALS AND METHODS: The gadoxetate-enhanced liver MR images of 30 patients acquired using the traditional breathing command and the subsequent 30 patients after training the technicians to use a modified breathing command were analyzed. A subgroup of patients (n = 8) underwent scans both by trained and untrained technicians. Images obtained using the traditional and modified breathing command were compared for the presence of breathing artefacts [respiratory artefact-based image quality scores from 1 (best) to 5 (non-diagnostic)]. RESULTS: There was a highly significant improvement in the arterial phase image quality scores in patients using the modified breathing command compared to the traditional one (P < 0.001). The percentage of patients with severe and extensive breathing artefacts in the arterial phase decreased from 33.3 % to 6.7 % after introducing the modified breathing command (P = 0.021). In the subgroup that underwent MRI using both breathing commands, arterial phase image quality improved significantly (P = 0.008) using the modified breathing command. CONCLUSION: Training technicians to use a modified breathing command significantly improved arterial phase image quality of gadoxetate-enhanced liver MRI. KEY POINTS: • A modified breathing command reduced respiratory artefacts on arterial-phase gadoxetate-enhanced MRI (P < 0.001). • The modified command decreased severe and extensive arterial-phase breathing artefacts (P = 0.021). • Training technicians to use a modified breathing command improved arterial-phase images.

Suction/Inspiration against resistance or standardized Mueller maneuver : a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study.

OBJECTIVE: Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. MATERIAL AND METHODS: The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. RESULTS: Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. CONCLUSION: Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. KEY POINTS: • Suction/Inspiration against resistance is promising to improve contrast density within the pulmonary artery. • Patients potentially suffering pulmonary embolism are able to follow suction/inspiration against resistance. • Contrast density after suction is superior in comparison to other breathing maneuvers.

Ultra-high-field magnetic resonance enterography in the diagnosis of ileitis (Neo-)terminalis: a prospective study.

BACKGROUND AND GOALS: Magnetic resonance (MR) enterography provides the advantages of conventional enteroclysis and those of cross-sectional imaging. Adequate luminal distension, combined with ultrafast sequences, results in excellent delineation of mural and extramural manifestations of Crohn's disease. Recent technical advances, including ultra-high-field strength MR with its capability to provide fast multiplanar images with excellent soft tissue contrast, are only rarely included in abdominal studies. STUDY: One hundred four consecutive patients with a proved or suspected diagnosis of ileitis terminalis were prospectively selected for MR imaging studies and ileocolonoscopy. The final diagnosis was based on histopathological findings or based on a combined endpoint of clinical, laboratory, endoscopic, and imaging findings. RESULTS: According to the endoscopic examination, stenosis was present in 26 patients (25%) and could be ruled out in 78 patients (75%). Total agreement between MR and endoscopy could be reached in 74 patients (71%). Histology indicated absence of inflammation in 50 patients (48%). MR and endoscopic findings were concordant in 38 patients (76%) and 37 patients (74%), respectively. Corresponding results by ileocolonoscopy were 37 true negative, 29 true positive, 4 false positive, and 12 false negative (sensitivity, 70.7%; specificity, 74%). CONCLUSIONS: MR enterography with a 3.0-T scanner is a powerful tool in the evaluation of ileal diseases, and has therefore made MR enterography the first-line modality at our institution in patients with suspected inflammatory bowel disease.

Diameter of occluded superficial femoral arteries limits percutaneous recanalization: preliminary results.

PURPOSE: To explore if the diameter of an occluded superficial femoral artery (SFA) can predict the technical success of percutaneous recanalization. METHODS: Two hundred patients (151 men; mean age 57 +/- 16 years) suffering from peripheral arterial occlusive disease were evaluated with duplex ultrasonography to measure arterial diameters and percent diameter reduction. Seventy-nine (39.5%) patients had segmental or complete SFA occlusions that ranged in age from 2 to 26 months (median 11). The majority of occlusions (45, 57.0%) were < or =10 cm long (range 10-35). Percutaneous recanalization was performed in 71 patients using either conventional angioplasty or local low-dose thrombolysis with rtPA. RESULTS: Diameters of 79 unilaterally occluded SFAs at the level of occlusion were 4.5 +/- 1.4 mm versus 5.7 +/- 1.3 mm for the patent contralateral artery (p=0.055). None of the 121 patent SFAs had diameters < or =3.5 mm, but 12 (15%) of the 79 occluded SFAs did, and none of these could be recanalized. The sensitivity of the 3.5-mm cut point to predict recanalization failure was 44% (specificity 100%). CONCLUSIONS; Our data suggest that occluded SFAs with a diameter reduction to < or =3.5 mm are not suitable for percutaneous recanalization, as the original arterial lumen cannot be reconstructed.

Whole-body MR imaging: evaluation of patients for metastases.

PURPOSE: To compare the results of whole-body magnetic resonance (MR) imaging with staging based on computed tomographic (CT), dedicated MR imaging, and nuclear scintigraphic results as standard of reference. MATERIALS AND METHODS: Fifty-one patients with known malignant tumors were included in the study. Patients were placed on a rolling table platform capable of moving the patient rapidly through the isocenter of the magnet bore. The thorax and the abdomen were imaged by using fast breath-hold T2-weighted sequences in the transverse plane. After intravenous administration of a paramagnetic contrast agent, three-dimensional gradient-echo data sets were collected in five stations and covered the body from the skull to the knees. Location and size of cerebral, pulmonary, hepatic, and osseous metastases were documented by two experienced radiologists. Whole-body MR imaging findings were compared with results obtained at skeletal scintigraphy, CT, and dedicated MR imaging. RESULTS: The mean examination time for whole-body MR imaging was 14.5 minutes. All cerebral, pulmonary, and hepatic metastases greater than 6 mm in diameter could be identified with whole-body MR imaging. Small pulmonary metastases were missed with MR imaging, which did not change therapeutic strategies, but MR imaging depicted a single hepatic metastasis that was missed with CT. Skeletal scintigraphy depicted osseous metastases in 21 patients, whereas whole-body MR imaging revealed osseous metastases in 24 patients. The additional osseous metastases seen with MR imaging were confirmed at follow-up examinations but did not result in a change in therapy. Whole-body MR imaging performed on a per-patient basis revealed sensitivity and specificity values of 100%. CONCLUSION: Whole-body MR imaging for the evaluation of metastases compared well with the reference techniques for cerebral, pulmonary, and hepatic lesions. Whole-body MR imaging was more sensitive in the detection of hepatic and osseous metastases than were the reference techniques.