68Ga-PSMA-PET/CT in comparison with 18F-fluoride-PET/CT and whole-body MRI for the detection of bone metastases in patients with prostate cancer: a prospective diagnostic accuracy study.

OBJECTIVES: To determine the diagnostic accuracy of 68gallium prostate-specific membrane antigen (PSMA)-based positron emission tomography/computed tomography (PET/CT) in comparison with 18F-fluoride-based PET/CT (NaF-PET/CT) and whole-body magnetic resonance imaging (WB-MRI) for the detection of bone metastases in patients with prostate cancer. METHODS: Sixty patients with prostate cancer were included in the period May 2016 to June 2017. The participants underwent three scans (index tests) within 30 days: a NaF-PET/CT, a WB-MRI and a PSMA-PET/CT. Experienced specialists assessed the scans. In the absence of a histological reference standard, the final diagnosis was determined as a panel diagnosis. Measures of the diagnostic performances of the index tests were calculated from patient-based dichotomous outcomes (0 or ≥ 1 bone metastasis) and pairwise compared (McNemar test). For each index test, the agreement with the final diagnosis with regard to the number of bone metastases detected (0, 1-5, > 5) and the inter-reader agreement was calculated (kappa coefficients). RESULTS: Fifty-five patients constituted the final study population; 20 patients (36%) were classified as having bone metastatic disease as their final diagnosis. The patient-based diagnostic performances were (sensitivity, specificity, overall accuracy) PSMA-PET/CT (100%, 100%, 100%), NaF-PET/CT (95%, 97%, 96%) and WB-MRI (80%, 83%, 82%). The overall accuracy of PSMA-PET/CT was significantly more favourable compared to WB-MRI (p = 0.004), but not to NaF-PET/CT (p = 0.48). PSMA-PET/CT classified the number of bone metastases reliably compared to the final diagnosis (kappa coefficient 0.97) and with an "almost perfect" inter-reader agreement (kappa coefficient 0.93). CONCLUSIONS: The overall accuracy of PSMA-PET/CT was significantly more advantageous compared to WB-MRI, but not to NaF-PET/CT. KEY POINTS: • PSMA-PET/CT assessed the presence of bone metastases correctly in all 55 patients • PSMA-PET/CT was more advantageous compared to WB-MRI • No difference was found between PSMA-PET/CT and NaF-PET/CT.

Plain magnetic resonance imaging as an alternative in evaluating inflammation and bowel damage in inflammatory bowel disease--a prospective comparison with conventional magnetic resonance follow-through.

OBJECTIVE: To compare prospectively the diagnostic accuracy of magnetic resonance imaging (MRI) without use of contrast medium orally or intravenously (plain MRI) with magnetic resonance follow-through (MRFT) in patients with inflammatory bowel disease (IBD). MATERIAL AND METHODS: Plain MRI was carried out in addition to MRFT, to which the patients were referred. All patients underwent both examinations on the same day. For the evaluation, the bowel was divided into nine segments. Two radiologists, blinded to clinical findings, evaluated bowel wall thickness, diffusion weighted imaging (DWI), and other inflammatory changes in each bowel segments. Further, hyperenhancement of the bowel was also evaluated in MRFT. RESULTS: A total of 100 patients (40 males and 60 females; median age: 38.5; range: 19-90) were enrolled; 44 with Crohn's disease (CD), 25 with ulcerative colitis (UC), 24 with IBD unclassified (IBD-U), and 7 had other diagnosis. Sensitivity, specificity, and accuracy in CD ranged 50-86%, 93-94%, and 91-92% for wall thickening and 49-82%, 85-93%, and 84-89% for DWI, respectively. Sensitivity, specificity, and accuracy in UC range 0-40%, 87-100%, and 80-100% for wall thickening and 0-52%, 83-94% and 76-92% for DWI, respectively. The κ values for bowel wall thickening, DWI, and mural hyperenhancement were detected with fair agreement (κ = 0.26-0.39) at both MRI examinations, whereas only bowel wall thickening in MRFT were detected with moderate agreement (κ = 0.47) Conclusion. Plain MRI cannot currently replace MRFT in the workup of patients with IBD. Further research on plain MRI is needed to improve the protocol.

Patient acceptance of whole-body magnetic resonance angiography: A prospective questionnaire study.

BACKGROUND: Whole-body magnetic resonance angiography (WB-MRA) is a noninvasive method for diagnosing the systemic distribution of atherosclerosis. Numerous studies have demonstrated the feasibility and diagnostic performance of WB-MRA, but no studies have investigated patient acceptance of this imaging method. PURPOSE: To measure patient acceptance of WB-MRA compared to the gold standard, digital subtraction angiography (DSA), in patients with peripheral arterial disease (PAD). MATERIAL AND METHODS: In a prospective design, 79 consecutive patients (51 male, mean age 67 years) with symptomatic PAD, scheduled to undergo both WB-MRA and DSA, were included. Patient acceptance of each imaging procedure was assessed with a postal questionnaire (13 questions). A five-point rank scale (1, no discomfort; 5, severe discomfort) was used to grade patient discomfort. RESULTS: One patient was excluded from data analysis (did not undergo DSA). Of the remaining 78 patients, 69 completed the questionnaire (response rate 88%). Overall discomfort scores were higher in DSA compared to WB-MRA (mean 2.1 and 1.7, respectively; P = 0.06). In WB-MRA, overall discomfort was strongly correlated to feeling confined in the MRI system (R = 0.77, P< 0.001). In DSA, discomfort was strongly correlated to arterial puncture (R = 0.66, P< 0.001) and contrast injection (R= 0.65, P< 0.001). Injection of iodinated contrast agent at DSA was graded more uncomfortable than injection of gadolinium-based contrast agent at WB-MRA (mean 2.1 vs. 1.5, respectively; P<0.001). Sixty-two patients (90%) were willing to repeat WB-MRA, and 64 patients (93%) would repeat DSA if they needed another vascular examination. Forty-one patients preferred WB-MRA (60%), 12 patients preferred DSA (17%), and 16 patients had no preference (23%). Patient preference of WB-MRA over DSA was statistically significant (P< 0.001). CONCLUSION: Patient acceptance of WB-MRA is superior to that of DSA in patients with PAD, with the majority of patients preferring WB-MRA.

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.

A prospective study comparing whole-body skeletal X-ray survey with 18F-FDG-PET/CT, 18F-NaF-PET/CT and whole-body MRI in the detection of bone lesions in multiple myeloma patients.

BACKGROUND: For decades, the most widely used imaging technique for myeloma bone lesions has been a whole-body skeletal X-ray survey (WBXR), but newer promising imaging techniques are evolving. PURPOSE: To compare WBXR with the advanced imaging techniques 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT), 18F-sodium fluoride (NaF) PET/CT and whole-body magnetic resonance imaging (WB-MRI) in the detection of myeloma bone lesions. MATERIAL AND METHODS: Fourteen patients with newly diagnosed multiple myeloma were prospectively enrolled. In addition to WBXR, all patients underwent FDG-PET/CT, NaF-PET/CT, and WB-MRI. Experienced specialists performed blinded readings based on predefined anatomical regions and diagnostic criteria. RESULTS: In a region-based analysis, a two-sided ANOVA test showed that the extent of detected skeletal disease depends on the scanning technique (P < 0.0001). Tukey's multiple comparison test revealed that WB-MRI on average detects significantly more affected regions than WBXR (P < 0.005), FDG-PET/CT (P < 0.0001), and NaF-PET/CT (P < 0.05). In a patient-based analysis, a Cochran's Q test showed that there are no significant differences in the proportion of patients with bone disease detected by the different scanning techniques (P = 0.23). Determination of intrareader variability resulted in Kappa coefficients corresponding to moderate (FDG-PET/CT) and substantial agreement (WB-MRI, WBXR, NaF-PET/CT). CONCLUSION: WB-MRI detects on average significantly more body regions indicative of myeloma bone disease compared to WBXR, FDG-PET/CT, and NaF-PET/CT. The lack of significance in the patient-based analysis is most likely due to the small number of study participants.

Preoperative CT versus diffusion weighted magnetic resonance imaging of the liver in patients with rectal cancer; a prospective randomized trial.

Introduction. Colorectal cancer is one of the most frequent cancers in the world and liver metastases are seen in up to 19% of patients with colorectal cancers. Detection of liver metastases is not only vital for sufficient treatment and survival, but also for a better estimation of prognosis. The aim of this study was to evaluate the feasibility of diffusion weighted MRI of the liver as part of a combined MR evaluation of patients with rectal cancers and compare it with the standard preoperative evaluation of the liver with CT. Methods. Consecutive patients diagnosed with rectal cancers were asked to participate in the study. Preoperative CT and diffusion weighted MR (DWMR) were compared to contrast enhanced laparoscopic ultrasound (CELUS). Results. A total of 35 patients were included, 15 patients in Group-1 having the standard CT evaluation of the liver and 20 patients in Group-2 having the standard CT evaluation of the liver and DWMR of the liver. Compared with CELUS, the per-patient sensitivity/specificity was 50/100% for CT, and for DWMR: 100/94% and 100/100% for Reader 1 and 2, respectively. The per-lesion sensitivity of CT and DWMR were 17% and 89%, respectively compared with CELUS. Furthermore, one patient had non-resectable metastases after DWMR despite being diagnosed with resectable metastases after CT. Another patient was diagnosed with multiple liver metastases during CELUS, despite a negative CT-scan. Discussion. DWMR is feasible for preoperative evaluation of liver metastases. The current standard preoperative evaluation with CT-scan results in disadvantages like missed metastases and futile operations. We recommend that patients with rectal cancer, who are scheduled for MR of the rectum, should have a DWMR of the liver performed at the same time.

Diagnosis of bladder tumours in patients with macroscopic haematuria: a prospective comparison of split-bolus computed tomography urography, magnetic resonance urography and flexible cystoscopy.

OBJECTIVE: The aim of this study was to compare split-bolus computed tomography urography (CTU), magnetic resonance urography (MRU) and flexible cystoscopy in patients with macroscopic haematuria regarding the diagnosis of bladder tumours. MATERIALS AND METHODS: In this prospective study, 150 patients underwent CTU, MRU and flexible cystoscopy. Two uroradiologists individually reviewed the images without any clinical information, using a questionnaire. Patient records and pathology reports were also reviewed. RESULTS: At flexible cystoscopy, MRU and CTU, 32, 19 and 15 bladder lesions were identified, respectively. Histopathology showed that 13 of the 29 biopsied lesions were transitional cell carcinomas. Compared with the histopathology, the sensitivity and specificity for detection of tumours by CTU and MRU were 61.5% and 94.9%, and 79.9% and 93.4%, respectively. False-positive detection of bladder tumours, compared with histopathology, was reported in seven CTUs and nine MRUs, whereas the number of false-negative findings was five for CTUs and three for MRUs. CONCLUSIONS: Split-bolus CTU or MRU cannot replace cystoscopy in cases of macroscopic haematuria. MRU has a higher sensitivity than split-bolus CTU, and is a potential alternative to flexible cystoscopy. Patients with a low risk of bladder cancer may forgo flexible cystoscopy if a bladder tumour is identified by either CTU or MRU, and proceed straight to transuretheral resection of the bladder.

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.

Whole-body magnetic resonance angiography with additional steady-state acquisition of the infragenicular arteries in patients with peripheral arterial disease.

The purpose of this investigation was to determine if addition of infragenicular steady-state (SS) magnetic resonance angiography (MRA) to first-pass imaging improves diagnostic performance compared with first-pass imaging alone in patients with peripheral arterial disease (PAD) undergoing whole-body (WB) MRA. Twenty consecutive patients with PAD referred to digital-subtraction angiography (DSA) underwent WB-MRA. Using a bolus-chase technique, first-pass WB-MRA was performed from the supra-aortic vessels to the ankles. The blood-pool contrast agent gadofosveset trisodium was used at a dose of 0.03 mmol/kg body weight. Ten minutes after injection of the contrast agent, high-resolution (0.7-mm isotropic voxels) SS-MRA of the infragenicular arteries was performed. Using DSA as the "gold standard," sensitivities and specificities for detecting significant arterial stenoses (>/=50% luminal narrowing) with first-pass WB-MRA, SS-MRA, and combined first-pass and SS-MRA were calculated. Kappa statistics were used to determine intermodality agreement between MRA and DSA. Overall sensitivity and specificity for detecting significant arterial stenoses with first-pass WB-MRA was 0.70 (95% confidence interval 0.61 to 0.78) and 0.97 (0.94 to 0.99), respectively. In first-pass WB-MRA, the lowest sensitivity was in the infragenicular region, with a value of 0.42 (0.23 to 0.63). Combined analysis of first-pass WB-MRA and SS-MRA increased sensitivity to 0.81 (0.60 to 0.93) in the infragenicular region, with specificity of 0.94 (0.88 to 0.97). Sensitivity and specificity for detecting significant arterial stenoses with isolated infragenicular SS-MRA was 0.47 (0.27 to 0.69) and 0.86 (0.78 to 0.91), respectively. Intermodality agreement between MRA and DSA in the infragenicular region was moderate for first-pass WB-MRA (kappa = 0.49), fair for SS-MRA (kappa = 0.31), and good for combined first-pass/SS-MRA (kappa = 0.71). Addition of infragenicular SS-MRA to first-pass WB MRA improves diagnostic performance.

Whole-body magnetic resonance angiography at 3 tesla using a hybrid protocol in patients with peripheral arterial disease.

The purpose of this study was to determine the diagnostic performance of 3T whole-body magnetic resonance angiography (WB-MRA) using a hybrid protocol in comparison with a standard protocol in patients with peripheral arterial disease (PAD). In 26 consecutive patients with PAD two different protocols were used for WB-MRA: a standard sequential protocol (n = 13) and a hybrid protocol (n = 13). WB-MRA was performed using a gradient echo sequence, body coil for signal reception, and gadoterate meglumine as contrast agent (0.3 mmol/kg body weight). Two blinded observers evaluated all WB-MRA examinations with regard to presence of stenoses, as well as diagnostic quality and degree of venous contamination in each of the four stations used in WB-MRA. Digital subtraction angiography served as the method of reference. Sensitivity for detecting significant arterial disease (luminal narrowing > or = 50%) using standard-protocol WB-MRA for the two observers was 0.63 (95%CI: 0.51-0.73) and 0.66 (0.58-0.78). Specificities were 0.94 (0.91-0.97) and 0.96 (0.92-0.98), respectively. In the hybrid protocol WB-MRA sensitivities were 0.75 (0.64-0.84) and 0.70 (0.58-0.8), respectively. Specificities were 0.93 (0.88-0.96) and 0.95 (0.91-0.97). Interobserver agreement was good using both the standard and the hybrid protocol, with kappa = 0.62 (0.44-0.67) and kappa = 0.70 (0.59-0.79), respectively. WB-MRA quality scores were significantly higher in the lower leg using the hybrid protocol compared to standard protocol (p = 0.003 and p = 0.03, observers 1 and 2). Distal venous contamination scores were significantly lower with the hybrid protocol (p = 0.02 and p = 0.01, observers 1 and 2). In conclusion, hybrid-protocol WB-MRA shows a better diagnostic performance than standard protocol WB-MRA at 3 T in patients with PAD.

Whole-body MR angiography with body coil acquisition at 3 T in patients with peripheral arterial disease using the contrast agent gadofosveset trisodium.

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 method's clinical application is warranted.

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

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.