MRI of heart morphology. Comparison of nongradient echo sequences with single- and multislice acquisition.

RATIONALE AND OBJECTIVES: A large variety of cardiac MRI sequences have been introduced for heart morphology evaluation. The aim of this study was to establish a practicable and robust examination protocol for standard high-field systems applying nongradient echo sequences with single- and multi-slice acquisition. METHODS: Fifty-one patients received electrocardiogramgated MRI of the heart with "black-blood" preparation, comparing three single-slice and three multislice sequences with a T1-weighted turbo spin echo reference sequence. Demarcation of the left ventricular myocardium and cavity and the extent of flow and motion artifacts were assessed. RESULTS: The myocardium and left ventricular cavity were depicted best with the single-slice T1- and T2-weighted turbo spin echo sequence. The nonbreath-hold multislice sequences produced marked artifacts and therefore were of poor diagnostic value. The TIRM haste sequence was best suited for fat suppression. The T2-weighted breath-hold single-shot sequence with half-Fourier imaging proved to be most appropriate for multislice imaging. CONCLUSIONS: Sufficient depiction of heart morphology with comprehensive evaluation of signal changes can be achieved using nongradient spin echo and turbo spin echo sequences with breath-holding. For rational imaging of myocardial and heart chamber morphology, multislice and single-slice sequences should be combined.

Gadolinium-enhanced elliptically reordered three-dimensional MR angiography in the assessment of hand vascularization before radial artery harvest for coronary artery bypass grafting: first experience.

RATIONALE AND OBJECTIVES: To assess the suitability of contrast-enhanced magnetic resonance angiography (MRA) in the preoperative evaluation of hand vasculature in potential candidates for radial artery bypass grafting. METHODS: In 21 patients, gadobenate dimeglumine-enhanced, three-dimensional gradient-echo sequences of both hands were performed, as well as a Doppler ultrasound study with radial artery compression. Doppler findings were correlated with MRA, focusing on the assessment of anastomoses between the vascular bed of the ulnar and radial arteries. RESULTS: One individual had to be excluded because of accidentally disclosed metal foreign bodies. Sufficient depiction of the hand vasculature was achieved in the remainder. Seventeen patients had evidence of adequate collateral flow between the ulnar and radial artery supply on Doppler ultrasound. Three patients exhibited inadequate collateral flow, with angiographic signs of vessel occlusion or missing collaterals between the palmar arches. Two patients presented with stenosis or occlusion of the radial artery. Magnetic resonance angiograms displayed great variations in hand vasculature and collateral formation, with no mismatch compared with Doppler ultrasound results. CONCLUSIONS: Contrast-enhanced MRA displays vascularization of the hand in detail and supplies ultrasound flow measurements for radial artery harvest, with high-resolution angiographic data about possible vessel variations and the presence of anastomoses between the radial or ulnar artery supply.

Pelvic imaging with a selenium-based detector (Thoravision). Comparison with screen-film radiography in 75 patients.

OBJECTIVE: To evaluate whether the selenium detector (Thoravision) provides sufficient diagnostic confidence in digital pelvic imaging compared with a conventional screen-film combination. METHODS: In 75 patients, pelvic imaging with conventional screen-film and isodose selenium radiography using a dedicated postprocessing mode was compared independently by three radiologists. The depiction of cortical and cancellous bone was evaluated in the iliac wings, sacral and pubic bones, acetabulum, femoral head, and trochanter. Demarcation of soft tissue was assessed in the iliac and trochanteric region. RESULTS: Visualization of cortical bone and soft tissue in the iliac area as well as soft tissue and cortical and cancellous bone in the trochanteric region was significantly superior with the selenium detector. However, conventional imaging was better in the trabecular bone of the sacral region, where results with the selenium system were particularly poor. CONCLUSIONS: The selenium detector (Thoravision) is advantageous in imaging soft tissue adjacent to the iliac wings and the trochanter, but results for the cancellous sacral bone are poor. Further modifications of postprocessing modes may lead to improved depiction of this critical pelvic area.

Neurovascular contact of the brain stem in hypertensive and normotensive subjects: MR findings and clinical significance.

BACKGROUND AND PURPOSE: About 20 years ago, a theory was put forward that neurovascular contact of the root entry zone (REZ) of the ninth and 10th cranial nerve is responsible for elevated blood pressure in patients with essential hypertension. To test this hypothesis, we used MR tomography and MR angiography to evaluate the presence and degree of neurovascular contact of the REZ of the ninth and 10th cranial nerves in patients with essential hypertension as compared with patients with renal parenchymal hypertension and normotensive healthy volunteers. METHODS: Patients with essential hypertension (group 1; n = 33), renal parenchymal hypertension (group 2; n = 30), and normotensive healthy volunteers (group 3; n = 25) underwent high-resolution (axial and coronal) brain stem MR imaging and MR angiography. The images were interpreted consensually by two radiologists who were blinded to the patients' hypertensive status. Neurovascular contact was graded as vessel contact without associated brain stem deformity (grade I), vessel contact with associated brain stem deformity (grade II), or vessel contact with associated deformity and displacement of the brain stem (grade III). RESULTS: Neurovascular contact of the REZ of the ninth and 10th cranial nerve on the left side was found in 48.5% in group 1, in 26.7% in group 2, and in 48.0% in group 3. The rate of neurovascular contact on the right side was 24.2%, 13.3%, and 40.0%, respectively. chi(2) analysis showed no statistical difference between the groups. CONCLUSION: Neurovascular contact is not more frequent in patients with essential hypertension than in normotensive control subjects or in those with secondary hypertension; therefore, MR imaging cannot aid patient selection for neurosurgical vascular decompression.

[Preoperative examination of potential kidney transplantation donors: value of gadolinium-enhanced 3D MR angiography in comparison with DSA and urography]. / Präoperative Untersuchung potentieller Nierenlebendspender: Wertigkeit der Gadoliniumverstärkten 3D-MR-Angiographie im Vergleich mit der DSA und Urographie.

PURPOSE: To assess a contrast-enhanced standardized MRA protocol for the presurgical evaluation of potential renal transplant donors. METHODS: Twenty-three potential donors for renal transplantations were examined with gadolinium-enhanced, two-phase MR angiograms (1.5 T) and DSA/urography for the number of renal arteries, the presence of aberrant arterial and venous branches, renal artery stenoses and anatomy of the renal collecting system and ureters. The diagnostic value was assessed by evaluating different image processing modalities and interobserver variability. RESULTS: Using maximum intensity projections (MIP) together with multiplanar reformatting (MPR), accessory arteries were detected with a sensitivity/specificity of 100%/98%. Depending on diagnostic experience, exclusive evaluation of MIP yielded a sensitivity/specificity of 67-100%/95-100%. Using MIP/MPR, venous depiction was good in 80%, with MIP solely in 30-40%. At least the proximal third of the ureter was visible in 67%. CONCLUSION: MPR/MIP evaluation of two-phase, contrast-enhanced MRA provides an excellent depiction of renal vessel anatomy for presurgical evaluation of renal transplant donors. Exclusive MIP assessment is less reliable and depends strongly on the examiner's experience. For sufficient visualization of the ureters, either additional measurements or low-dose diuretic injection have to performed.

Background suppression using magnetization preparation for contrast-enhanced 3D MR angiography of the pelvic and lower leg arteries.

PURPOSE: To develop and evaluate non-slab-selective magnetization preparation in contrast-enhanced 3D-MR angiography. METHODS: An ultrafast spoiled mr angiography sequence (FLASH) with non-selective inversion prepulses for background suppression was implemented on a 1.5 T MR system. In 11 patients gadobenate dimeglumine-enhanced mr-angiography of the pelvic and lower leg arteries was performed using the AngioSURF device. Source data was evaluated for contrast-to-noise-ratio, image quality and the extent of background suppression. RESULTS: Background suppression and selective vessel contrast was excellent in all vascular levels. The mr protocol was comfortable and easy-to-handle. Abandonment of precontrast-series acquisition simplified the examination procedure markedly. CONCLUSIONS: Magnetization preparation provides efficient suppression of the background signal in contrast-enhanced 3D mr angiography of the pelvic and lower leg arteries. Since no subtraction technique is needed, moving-bed and whole body MRA-protocols can be simplified significantly.

Epithelioid angiosarcoma of the scapula.

Epithelioid angiosarcoma is a rare variation of an angiosarcoma and its localization in the bone is exceptionally infrequent. This report presents the case of a 48-year-old male with an epithelioid angiosarcoma of the scapula. In CT and MRI scans an inhomogeneous tumour with osseous destructions, lytic areas, central necrosis and marginal hyperperfusion was observed. The bordering skeletal muscles were already infiltrated. The tumour was treated initially with neoadjuvant chemotherapy, followed by dose escalation, peripheral blood stem cell transplantation and resection of the lesion. Despite advanced local tumour stage at initial presentation, the patient is in complete remission.

Detection and characterization of benign focal liver lesions with multislice CT.

MDCT is a rapidly evolving technique that significantly improves CT imaging for several indications including depiction of focal benign lesions. Imaging mainly profits from improved longitudinal spatial resolution allowing high-quality non-axial reformations and 3D reconstructions and CT angiography as well as rapid accurate multiphase imaging with short breath-holding periods. This review provides an overview of the current status of MDCT with respect to liver imaging and the implications for characterizing benign focal liver lesions. MDCT currently allows the acquisition of thin slices in daily routine diagnostics providing an improved detection rate of small liver lesions. Whereas large benign focal liver lesions exhibit typical patterns of morphology, attenuation and perfusion, which also may be assessed with single-slice scanners, small lesions remain challenging even with MDCT, since the specific criteria for confident diagnosis become more ambiguous. Here, MR imaging provides more detailed information about tissue components and the availability of liver-specific contrast agents, adding further impact to this technique. With respect to dose considerations, the number of necessary multiphase scans as well as the application of very thin collimation should be strictly checked for each patient undergoing MDCT based on the individual clinical situation and question.

Cerebral and renal embolization after lymphography in a patient with non-Hodgkin lymphoma: case report.

An unusual case of lipid embolization to brain and kidney after lymphography in a patient with non-Hodgkin lymphoma of the upper anterior mediastinum is reported. Contrast material-enhanced echocardiography demonstrated a right-to-left shunt to the left atrium without evidence of a patent foramen ovale. Echo contrast particles were transiently present within the tumor surrounding the great vessels.

Diagnosis of the hypothenar hammer syndrome by high-resolution contrast-enhanced MR angiography.

Our objective was to describe the imaging features of hypothenar hammer syndrome using minimally invasive contrast-enhanced MR angiography in comparison with oscillography study. In five patients with hypothenar hammer syndrome Gd-BOPTA-enhanced elliptically reordered 3D pulse sequence MR was compared with oscillography findings and clinical symptoms focusing on angiographic appearance of vessel injury, distribution pattern of hand vasculature and joining branches between the radial and ulnar artery supply. All patients showed segmental occlusion at the site of trauma impact with varying involvement of the superficial palmar arch, common volar digital arteries. Embolic disease was present in 50% of patients and could be clearly identified with MRA. Good correspondence was found between angiographic appearance including the presence of collaterals, clinical symptoms and oscillography. Bilateral comparison was helpful in distinguishing between vessel variants and pathology. Bilateral Gd-BOPTA-enhanced MR angiography is a minimally invasive method to depict clearly the localization and extent of vessel injury in hypothenar hammer syndrome providing valuable information about distribution pattern of hand vasculature and presence of collaterals; however, no flow data can be obtained.

Optimization of contrast-enhanced MR angiography of the hands with a timing bolus and elliptically reordered 3D pulse sequence.

Our objective was to optimize bolus administration and sequence setting in gadolinium-enhanced magnetic resonance (MR) angiography of the hands. Elliptically reordered three-dimensional (3D) spoiled gradient-echo sequence with non-slab-selective radio frequency excitation was optimized according to the measurements of arterial and venous time-signal curves in 21 patients. Great variations in bolus arrival time and arterio-venous transit time could be observed. In most patients high-quality arterial depiction could be obtained with minor venous contamination. Contrast-to-noise, spatial resolution, and selective arterial filling is still a challenge for 3D MR angiography of the hand but can be optimized using Gadolinium-BOPTA and a dedicated pulse sequence setting with exact bolus timing.

Radiologic findings in lymphangioma of the posterior tibial nerve.

A case of lymphangioma of the posterior tibial nerve is reported. MRI showed an elongated multiseptated cystic lesion along the tibial nerve leading to axonal degeneration and progressive left calf pain. A similar cystic lesion in a second patient was shown to be a ganglion. The diagnosis was made by surgical resection.

Cardiac phase contrast gradient echo MRI: characterization of abnormal left ventricular wall motion in patients with ischemic heart disease.

PURPOSE: In our patient study, we examined the clinical usefulness of phase contrast velocity mapping for the detection and characterization of localized abnormalities of left ventricular motion. MATERIALS AND METHODS: Velocity encoding is based on the fact that motion in the presence of a magnetic field gradient causes a change of the phase of the MRI signal that is proportional to the velocity of tissue motion. Left ventricular motion was characterized by parameters describing rotation and contraction/dilatation, respectively. We examined 34 patients with localized abnormalities of left ventricular motion due to ischemic heart disease. RESULTS: Three patients could not be sufficiently evaluated due to technical problems including varying positions of the heart during successive breathhold periods. In 27 of the remaining 31 patients, MRI could demonstrate abnormal radial velocities that corresponded fully or partly with perfusion deficits in single photon emission computed tomography or positron emission tomography. The abnormalities were most pronounced in early diastole. Rotational velocities did not show any regional changes. CONCLUSION: Our study showed that our technique is suitable for the detection and characterization of localized abnormalities of left ventricular motion in patients with ischemic heart disease.

Contrast-enhanced subtraction MR angiography in occlusive disease of the pelvic and lower limb arteries: results of a prospective intraindividual comparative study with digital subtraction angiography in 76 patients.

PURPOSE: The purpose of this work was to evaluate the feasibility and clinical use of MR angiography (MRA) for examining the pelvic and lower limb arteries in patients with arterial occlusive disease. METHOD: Seventy-six patients with clinical signs of peripheral arterial occlusive disease were included in the study. MRA was performed using a fast contrast-enhanced high-resolution 3D technique that covered the area from the distal abdominal aorta to the distal lower limbs in two examination steps. RESULTS: In all patients, diagnostic images comparable with those of conventional intraarterial digital subtraction angiography (DSA) could be obtained. No false-negative findings were seen in the iliac, femoral, or popliteal arteries. Ten to 16% of the mild stenoses and 6-14% of the severe stenoses, mainly in the crural vessels, were overgraded compared with intraarterial DSA. Particularly in patients with proximal severe obstructions or occlusions, the crural segments could be depicted more clearly due to decreased arterial runoff in conventional angiography. CONCLUSION: The consistency of the excellent depiction of the vascular territories of the distal aorta and the pelvic and lower limb arteries in a standardized setting suggests great potential for the use of MRA in the primary diagnosis of peripheral arterial occlusive disease.