Purpose: To evaluate differences in the magnitude and time course of renal cortical contrast uptake in patients with minimal, moderate, and severe renal artery stenosis (RAS) using contrast-enhanced magnetic resonance renography (CE-MRR).Materials and Methods: CE-MRR was performed on 56 patients with renovascular disease using a three-dimensional volume interpolated breath-hold examination (VIBE) perfusion sequence. After administration of 2 mL of contrast, nine sequential axial VIBE datasets were acquired: at baseline, 7, 14, 21, 45, 60, 120, 180, and 240 seconds. Aortic peak signal enhancement and cortical peak signal enhancement through the mid portion of each kidney was recorded, along with the time delay between each peak. Each renal artery was subsequently examined using threedimensional contrast-enhanced MR angiography, and graded as being minimally (0%-30%), moderately (31%-70%), or severely (71%-100%) stenotic.Results: When the data were subdivided by RAS category, the cortical to aortic peak enhancement ratio (CAPR) reduced with increasing RAS. Further, the cortical to aortic time delay (CATD) increased with increasing RAS. These measurements were statistically significant between patients with minimal and moderate RAS compared to severe RAS Conclusion: CE-MRR can assist in the differentiation of patients with minimal or moderate RAS from those with severe RAS.

The aim of the study was to achieve earlier diagnosis of malignant cord compression (MCC) using urgent magnetic resonance imaging (MRI) for selected patients. A comparison was carried out of the current prospective audit of 100 patients referred by a general practitioner or a consultant over 32 months with both a previous national Clinical Research and Audit Group (CRAG) prospective audit (324 cases of MCC) and an earlier retrospective audit of 104 patients referred with suspected MCC. A telephone hotline rapid-referral process for patients with known malignancy and new symptoms (severe nerve root pain ± severe back pain) was designed. Patients were considered for urgent MRI after discussion with a senior clinician responsible for the hotline. Appropriate referrals were discussed with radiology and oncology ensuring timely MRI reporting and intervention. The main outcome measures are as follows: time from referral to diagnosis; time from the onset of symptoms to diagnosis; and mobility at diagnosis. A total of 50 patients (52%) of those scanned had either MCC (44) or malignant nerve root compression (6) compared with the earlier rate of 23 out of 104 patients (22%). Ten out of 44 MCC patients (23%) were paralysed at diagnosis, compared with 149 out of 324 (46%) in the CRAG audit. Time from reporting pain to diagnosis was 32 days compared with 89 days in the CRAG audit. Median time from referral to diagnosis was 1 day, again considerably shorter than the CRAG audit time of 15 days (interquartile (IQ) range: 3–66). In patients at risk of MCC, fast-track referral with rapid access to MRI reduces time between symptom onset and diagnosis, improves mobility at diagnosis and reduces the number of negative MRI scans.

, a manganese-containing hepatobiliary contrast agent, is excreted in bile. We review the principles and practice of a contrast-enhanced MRC technique using mangafodipir and compare it with standard T2-weighted magnetic resonance cholangiography (MRC) sequences. Potential applications include the evaluation of leaks and strictures; the assessment of drainage in normal, surgically by-passed, stented and obstructed biliary systems; the diagnosis of cholecystitis; and the evaluation of normal and variant biliary anatomy. THE CURRENT PRACTICE of magnetic resonance cholangiography (MRC) relies on multi-planar thick and thin slice heavily T2-weighted (T2W) fast spin-echo techniques. These MR hydrographic sequences, while demonstrating anatomy, have a limited ability to demonstrate function.Mangafodipir trisodium (Teslascan™, Nycomed Amersham, Oslo, Norway) is an MR contrast agent that contains the paramagnetic metal, manganese (Mn 2ϩ ), which shortens the T1 relaxation time of neighboring protons, providing a positive contrast effect on T1-weighted (T1W) sequences. The manganese is bound to DPDP, a vitamin B6 analogue. Following intravenous injection, the manganese is removed from its DPDP ligand. The manganese binds to plasma proteins and is rapidly cleared from the blood. Seventy to 80% of the manganese is taken up by normal hepatocytes and the liver parenchyma becomes hyperintense on T1W sequences (1-3). The manganese is then transported into the bile, which also becomes hyperintense. A potential therefore exists to use this agent as a positive biliary magnetic resonance imaging (MRI) contrast agent on a T1W sequence.We aimed to demonstrate potential functional applications of a contrast-enhanced MRC technique (CE-MRC) using mangafodipir. IMAGING TECHNIQUE Contrast AdministrationThe standard recommended dose of mangafodipir is 0.005 mmol/kg (0.5 mL/kg). For the average 70 kg patient, this usually involves the slow intravenous administration of 35 mL of mangafodipir (0.35 mmol), followed by 20 mL of saline. Imaging ProtocolOur current MRC protocol is based on a 1.5-T Siemens Symphony (Siemens Medical Systems, Erlangen, Germany) using a phased array coil. Our standard MRC protocol involves initial axial and coronal true fast imaging with steady state precession (FISP) sequences that are performed to localize the hepatobiliary tree. Coronal and coronal oblique thick slab MRC T2 TSE (4500/950/50 mm slab/512 matrix) and thin slice half-Fourier acquisition single-shot turbo spin-echo (HASTE) (ϱ/90 effective/4-mm slices/256 ϫ 512 matrix) MRC sequences are then performed. In most instances CE-MRC is not performed, and we would proceed to CE-MRC in less than 10% of cases.Without moving the patient, mangafodipir is administered as described above. Axial two-dimensional T1W sequences are performed at 10-minute intervals until there is adequate opacification of the biliary tree (typically 20 -30 minutes). At this time a three-dimensional coronal T1W gradient sequence (TR 6.2/TE 2.24/ 15°/32 partitions/effective thickness 1.8/f...

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