Vibeke Løgager

Nephrogenic systemic fibrosis (NSF): a late adverse reaction to some of the gadolinium based contrast agents

Abstract Until recently it was believed that extracellular gadolinium based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium based contrast agents may trigger the development of nephrogenic systemic fibrosis, a generalised fibrotic disorder, in renal failure patients. Accordingly, the use of gadodiamide and gadopentate dimeglumine for renal failure patients was banned in Europe in spring 2007. The same two compounds should only be used cautiously in patients with moderate renal dysfunction. The current paper reviews the situation (July 2007) regarding gadolinium based contrast agent and the severe delayed reaction to some of these agents. The fear of nephrogenic systemic fibrosis should not lead to a denial of a well indicated enhanced magnetic resonance imaging examination.

Update on Nephrogenic Systemic Fibrosis

Gadolinium-based contrast agents were for many years considered safe, but this is no longer the case. The least stable agents may trigger the development of nephrogenic systemic fibrosis (NSF), a generalized fibrotic disorder, in renal failure patients. The use of gadodiamide and gadopentetate dimeglumine is now contraindicated in Europe and Japan in patients who have a glomerular filtration rate less than 30 mL/min/1.73 m(2), including those on dialysis. The fear of NSF, however, should not lead to an enhanced MR imaging examination being denied when there is a good clinical indication to give a gadolinium-based contrast agent.

Enhanced computed tomography or magnetic resonance imaging: a choice between contrast medium-induced nephropathy and nephrogenic systemic fibrosis?:

For more than 10 years, it has been believed that it would be better for the kidneys if patients with reduced renal function were referred to enhanced magnetic resonance imaging (MRI) rather than undergoing radiography (e.g., arteriography, computed tomography [CT]) with iodinated contrast media (CM) (20). It may indeed be better for the kidneys, but recently it has been shown that it may be associated with another severe adverse reaction: a potentially disabling and life-threatening disease, nephrogenic systemic fibrosis (NSF), may occur in the weeks following exposure to certain extracellular gadolinium-based contrast media (13, 19). Thus, a patient with reduced renal function (chronic kidney disease [CKD] stage 4 and 5: glomerular filtration rate [GFR]v30 ml/min) faces the unpleasant choice of risking contrast medium-induced nephropathy (CIN) after administration of iodine-based CM or NSF after exposure to gadolinium-based CM (17). This new knowledge has complicated work in the imaging department.

Apparent diffusion coefficient ratio correlates significantly with prostate cancer gleason score at final pathology

To evaluate the correlation between apparent diffusion coefficient measurements (ADCtumor and ADCratio) and the Gleason score from radical prostatectomy specimens.

Unenhanced MR Imaging in adults with clinically suspected acute appendicitis

PURPOSE The purpose of the study was to evaluate unenhanced Magnetic Resonance Imaging (MRI) for the diagnosis of appendicitis or another surgery-requiring condition in an adult population scheduled for emergency appendectomy based on a clinical diagnosis of suspected acute appendicitis. MATERIALS AND METHODS The prospective study included 48 consecutive patients (29 female, 19 male, 18-70 years old, mean age=37.1 years). MRI examination was designed to be comfortable and fast; no contrast was administered. The sequences were performed during quiet respiration. The MRI findings were reviewed by two radiologists and one surgeon independent of each other and compared with surgical and pathological records. RESULTS According to the surgical and histopathological findings 30 of 48 patients (63%) had acute appendicitis. Of the remaining 18 patients, 4 patients had no reasons for the clinical symptoms and 14 patients had other pathology. For the three reviewers the performance of MRI in the diagnosis of acute appendicitis showed the following sensitivity, specificity and accuracy ranges: 83-93%, 50-83% and 77-83%. Moderate (κ=0.51) and fair (κ=0.31) interobserver agreements in the MR diagnosis of acute appendicitis were found between the reviewers. Sensitivity, specificity and accuracy values for overall performance of MRI in detecting pelvic abnormalities were 100%, 75% (3 of 4 healthy patients were identified by MRI) and 98%, respectively. CONCLUSION Unenhanced fast MRI is feasible as an additional fast screening before the appendectomy. It may prevent unnecessary surgeries. The fast MRI examination can be adequately performed on an MRI unit of broad range of field strengths.

Early experience with multiparametric magnetic resonance imaging-targeted biopsies under visual transrectal ultrasound guidance in patients suspicious for prostate cancer undergoing repeated biopsy

Abstract Objectives. The purpose of this study was to investigate the detection rate of prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsies (mp-MRI-bx) in patients with prior negative transrectal ultrasound biopsy (TRUS-bx) sessions without previous experience of this. Material and methods. Eighty-three patients with prior negative TRUS-bx scheduled for repeated biopsies due to persistent suspicion of PCa were prospectively enrolled. mp-MRI was performed before biopsy and all lesions were scored according to the Prostate Imaging Reporting and Data System (PI-RADS) and Likert classification. All underwent repeated TRUS-bx (10 cores) and mp-MRI-bx under visual TRUS guidance of any mp-MRI-suspicious lesion not targeted by systematic TRUS-bx. Results.PCa was found in 39 out of 83 patients (47%) and mp-MRI identified at least one lesion with some degree of suspicion in all 39 patients. Both PI-RADS and Likert scoring showed a high correlation between suspicion of malignancy and biopsy results (p < 0.0001). Five patients (13%) had cancer detected only on mp-MRI-bx outside the TRUS-bx areas (p = 0.025) and another seven patients (21%) had an overall Gleason score upgrade of at least one grade based on the mp-MRI-bx. Secondary PCa lesions not visible on mp-MRI were detected by TRUS-bx in six out of 39 PCa patients. The secondary foci were all Gleason 6 (3 + 3) in 5–10% of the biopsy core. According to the Epstein criteria, 37 out of 39 cancer patients were classified as clinically significant. Conclusion. Using mp-MRI, even without previous experience, can improve the detection rate of significant PCa at repeated biopsy and allows more accurate Gleason grading.

Prostate cancer: 1.5 T endo-coil dynamic contrast-enhanced MRI and MR spectroscopy-correlation with prostate biopsy and prostatectomy histopathological data

PURPOSE To investigate diagnostic accuracy of detection of prostate cancer by magnetic resonance: to evaluate the performance of T2WI, DCEMRI and CSI and to correlate the results with biopsy and radical prostatectomy histopathological data. MATERIALS AND METHODS 43 patients, scheduled for radical prostatectomy, underwent prostate MR examination. Prostate cancer was identified by transrectal ultrasonographically (TRUS) guided sextant biopsy. MR examination was performed at 1.5 T with an endorectal MR coil. Cancer localisation was performed on sextant-basis--for comparison between TRUS biopsy, MR techniques and histopathological findings on prostatectomy specimens. RESULTS Prostate cancer was identified in all 43 patients by combination of the three MR techniques. The detection of prostate cancer on sextant-basis showed sensitivity and specificity: 50% and 91% for TRUS, 72% and 55% for T2WI, 49% and 69% for DCEMRI, and 46% and 78% for CSI. CONCLUSION T2WI, DCEMRI and CSI in combination can identify prostate cancer. Further development of MR technologies for these MR methods is necessary to improve the detection of the prostate cancer.

Biparametric versus multiparametric MRI in the diagnosis of prostate cancer.

Background Since multiparametric magnetic resonance imaging (mp-MRI) of the prostate exceeds 30 min, minimizing the evaluation time of significant (Gleason scores > 6) prostate cancer (PCa) would be beneficial. A reduced protocol might be sufficient for the diagnosis. Purpose To study whether a short unenhanced biparametric MRI (bp-MRI) matches mp-MRI in detecting significant PCa. Material and Methods A total of 204 men (median age, 65 years; mean ± SD, 64.1; range 45–75 years; median serum PSA level, 14 ng/mL; range, 2.2–120 ng/mL; median prostate volume, 60 mL; range, 23–263 mL) fulfilled the criteria for being enrolled. They underwent mp-MRI and prostate biopsy from January through June 2014. Of the included patients, 9.3% underwent prostatectomy, 90.7% had TRUS-bx, and 10.8 had MRI-targeted TRUS-bx. Two radiologists separately assessed the mp-MRI examination (T2-weighted [T2W] imaging, diffusion-weighted imaging [DWI], apparent diffusion coefficient map [ADC-map] and dynamic contrast-enhanced imaging [DCE]). Two months later, the bp-MRI version (T2W imaging, DWI, and ADC-map) was evaluated. Results Reader 1: Assessing mp-MRI: 0 false negatives, sensitivity of 1, and specificity 0.04. Assessing bp-MRI: four false negatives, sensitivity of 0.94, and specificity 0.15. Reader 2: Assessing mp-MRI: five false negatives, sensitivity of 0.93, and specificity 0.16. Assessing bp-MRI: three false negatives, sensitivity of 0.96, and specificity 0.15. Intra-reader agreement Cohen’s Kappa (κ) was 0.87 for reader 1 (95% confidence interval [CI], 0.83–0.92) and 0.84 for reader 2 (95% CI 0.78–0.89). Conclusion Bp-MRI is as good as mp-MRI at detecting PCa. A large prospective study seems to be strongly warranted.

Patient acceptance of MR colonography with improved fecal tagging versus conventional colonoscopy

OBJECTIVE Conventional colonoscopy (CC) is the gold standard for colonic examinations. However, patient acceptance is not high. Patient acceptance is influenced by several factors, notably anticipation and experience. This has led to the assumption that patient acceptance would be higher in non-invasive examinations such as MR/CT colonography (MRC/CTC) and perhaps even higher without bowel preparation. The purpose of this study was to evaluate patient acceptance of MRC with fecal tagging versus CC. MATERIALS AND METHODS In a 14-month period, all patients first-time referred to our department for CC were asked to participate in the study. Two days prior to MRC, patients ingested an oral contrast mixture (barium/ferumoxsil) together with four meals each day. Standard bowel purgation was performed before CC. Before and after MRC and CC a number of questions were addressed. RESULTS Sixty-four (34 men, 30 women) patients referred for CC participated in the study. 27% had some discomfort ingesting the contrast mixture, and 49% had some discomfort with the bowel purgation. As a future colonic examination preference, 71% preferred MRC, 13% preferred CC and 15% had no preference. If MRC was to be performed with bowel purgation, 75% would prefer MRC, 12% would prefer CC and 12% had no preference. CONCLUSION This study shows that there is a potential gain in patient acceptance by using MRC for colonic examination, since MRC is considered less painful and less unpleasant than CC. In addition, the results indicate that patients in this study prefer fecal tagging instead of bowel purgation.

Whole-body MR Angiography with Body Coil Acquisition at 3 T in Patients with Peripheral Arterial Disease Using the Contrast Agent Gadofosveset Trisodium1

RATIONALE AND OBJECTIVES Whole-body magnetic resonance angiography (WB-MRA) at 3 T with body coil acquisition has not previously been investigated. In this study, WB-MRA was performed in this manner using the blood pool contrast agent gadofosveset trisodium. MATERIALS AND METHODS Eleven consecutive patients (five men, six women) with symptomatic peripheral arterial disease (two with critical limb ischemia, nine with claudication) were examined. Conventional digital subtraction angiography (DSA) of the aorta and the inflow and runoff arteries was used as the reference method. WB-MRA was performed using four slightly overlapping stations covering the arteries from the neck to the ankles. The arterial system was divided into 42 segments that were analyzed for the presence of significant arterial disease (> or =50% luminal narrowing or occlusion) by two blinded observers. RESULTS Sensitivities for detecting a significant arterial lesion with WB-MRA using gadofosveset as the contrast agent were 0.66 (95% confidence interval [CI], 0.49-0.79) and 0.68 (95% CI, 0.52-0.81) for the two observers. Specificities were 0.82 (95% CI, 0.74-0.88) and 0.93 (95% CI, 0.87-0.96), respectively. Intermodality agreement between WB-MRA and DSA was moderate to good, with overall kappa values of 0.44 (95% CI, 0.29-0.59) and 0.63 (95% CI, 0.5-0.77) for the two observers. Interobserver agreement for WB-MRA was good, at kappa = 0.60 (95% CI, 0.50-0.71). CONCLUSION WB-MRA at 3 T with body coil acquisition in patients with peripheral arterial disease showed good reproducibility but only moderate to good agreement with DSA. Further assessment of the methods clinical application is warranted.