Signal changes in liver and spleen after Endorem administration in patients with and without liver cirrhosis

The goal of this study was to compare the effect of Endorem on the signal intensity of the spleen in patients with normal liver tissue and in patients with liver cirrhosis. Thirty patients with normal liver tissue and 47 with liver cirrhosis were examined before and after i. v. Endorem administration. The patients were examined with a 1.5-T magnet system (Magnetom Vision) using a semiflexible cp-array coil. Three different pulse sequences were used: a T1-weighted gradient-echo sequence, a T2-weighted fast spin-echo sequence with spectral fat suppression, and a T2^*-weighted gradient-echo sequence. The signal-to-noise ratios (SNRs) of two areas of the liver and spleen were determined. The mean SNRs of the liver and spleen in patients with and without liver cirrhosis were compared. For assessment of statistical significance, the t-test at a level of P < 0.05 was applied. After i. v. administration of Endorem, no differences were seen with the T1-weighted gradient-echo sequence for the liver and spleen and, with the T2-weighted fast spin-echo sequence, no differences were found for the spleen. Significant differences between both groups were seen for the liver with the T2-weighted fast spin-echo sequence. The SNR in the noncirrhotic liver group was 57.4 % lower than the SNR in the cirrhotic liver group. With the T2^*-weighted gradient-echo sequence, the SNRs of the liver and spleen in the noncirrhotic liver group, compared with the cirrhotic liver group, were 126.8 % and 45.6 % less, respectively. The effect of Endorem on the liver in patients with Child C-stage liver cirrhosis was 32.1 % less than in patients with Child B-stage liver cirrhosis. Likewise, the Endorem effect on the spleen was 27.1 % less in patients with Child C-stage compared with Child B-stage liver cirrhosis. Hepatic and splenic uptake of Endorem is significantly decreased in patients with liver cirrhosis. Received: 3 February 1999; Revision received: 21 October 1999; Accepted: 27 October 1999     

Superparamagnetic iron oxide-mediated hepatic signal intensity change in patients with and without cirrhosis: pulse sequence effects and Kupffer cell function

PURPOSE: To analyze superparamagnetic iron oxide (SPIO)-mediated hepatic signal intensity change in cirrhotic and noncirrhotic liver and to investigate the relationship between pulse sequence effects in SPIO-enhanced magnetic resonance (MR) imaging for hepatic cirrhosis. MATERIALS AND METHODS: Twelve patients with and 12 patients without cirrhosis underwent T2-weighted fast spin-echo, T2*-weighted gradient-echo (GRE), and T1-weighted GRE MR imaging before and twice (early and late phase) after SPIO administration. To assess the effect of SPIO, postcontrast relative signal-to-noise ratio (SNR) changes were statistically analyzed with repeated measurements analysis of variance for each pulse sequence. RESULTS: No interaction was shown between groups and data time points for any pulse sequence. There was no significant difference in mean hepatic relative SNR change on T2-weighted fast spin-echo images between the cirrhotic group and noncirrhotic group (-38.6% and -40.7%, early phase; -42.2% and -49.6%, late phase, respectively). For GRE images, statistically significant differences in mean hepatic relative SNR change were found between the cirrhotic group and noncirrhotic group (-14.2% and -44.5%, early phase; -28.5% and -56.4%, late phase on T2*-weighted GRE images (P <.001); 31.8% and 12.9%, early phase; 23.8% and 2.2%, late phase on T1-weighted GRE images (P <.05), respectively. CONCLUSION: Decreased overall phagocytic activity in cirrhotic liver is more likely due to Kupffer cell dysfunction than to Kupffer cell depletion, since magnetic susceptibility effects on T2*-weighted GRE images depend on intracellular SPIO cluster size.     

Gadobenate dimeglumine (BOPTA) enhanced MR imaging: Patterns of enhancement in normal liver and cirrhosis

To determine whether gadobenate dimeglumine (BOPTA) will adequately enhance cirrhotic liver parenchyma, and to document the enhancement patterns in cirrhosis, 14 cirrhotic and 20 non-cirrhotic patients were evaluated before and 60–120 minutes after gadolinium-BOPTA. Proof of liver cirrhosis was biopsy (6), surgical resection (3), and clinical follow-up (5). Enhancement effects were compared quantitatively by determining the liver signal-to-noise ratio (SNR) and signal enhancement in both populations. Qualitatively assessment of the liver enhancement was performed and classified as homogeneous or heterogeneous. Quantitative analysis: cirrhotic liver parenchyma presented a higher increase in SNR values, relative to noncirrhotic liver parenchyma, on postcontrast images. Likewise the signal enhancement of cirrhotic liver parenchyma was superior to non-cirrhotic liver on T1-weighted SE images (P = .02) and in-phase GRE images (P < .001). There was no statistical difference on out-of-phase GRE images. Qualitative analysis: on T1-weighted SE postcontrast images, cirrhotic liver parenchyma showed a homogeneous enhancement in 7 patients and heterogeneous in 7. Whereas on GRE images, cirrhotic parenchyma showed heterogeneous enhancement in 9 patients and homogeneous in 5 patients. The heterogeneous enhancement was due to the presence of hypointense nodules in 7 patients and hyperintense nodules in 2 patients. In conclusion, our study has shown that the hepatobiliary contrast agent Gd-BOPTA is effective in the cirrhotic liver, demonstrating an increased liver enhancement compared with non-cirrhotic patients.     

Comparison of inversion recovery fast spin-echo (FSE) with T2-weighted fat-saturated FSE and T1-weighted MR imaging in bone marrow lesion detection

 Objective To prospectively compare inversion recovery (IR) fast spin-echo (FSE) with T1-weighted spin-echo (SE) and T2-weighted chemical-shift fat-saturated (FS) FSE magnetic resonance sequences in the detection of bone marrow abnormality. Design. Twenty-nine sets of T1-weighted SE [400–640/10–20 (TR/TE)], T2-weighted FS-FSE [2400–3800/91–112/8 (TR/TE/ETL)], and IR-FSE [3700–6000/12–14/170/8 (TR/TE/T1/ETL)] images were acquired with a 1.5-T magnet in 27 patients with bone marrow lesions. The visibility, margination, and extent of 41 lesions, image quality, contrast, and artifacts were qualitatively and quantitatively compared. Results. The lesions were more conspicuous on the IR-FSE than on the T1-weighted SE and T2-weighed FS-FSE images. The extent of lesions was similar for all three sequences. Image quality was better and there were fewer motion artifacts on the T1-weighted images. The mean lesion contrast-to-noise ratio was significantly higher on the T1-weighted images (p<0.05). Conclusion. The IR-FSE sequence is highly sensitive for detecting bone marrow pathology, with scan time comparable to the T1-weighted SE and T2-weighted FS-FSE sequences.     

Multifocal nodular fatty infiltration of the liver mimicking metastatic disease on CT: imaging findings and diagnosis using MR imaging

The aim of this study was to describe the MR appearance of multifocal nodular fatty infiltration of the liver (MNFIL) using T1-weighted in-phase (IP) and opposed-phase (OP) gradient-echo as well as T2-weighted turbo-spin-echo sequences with fat suppression (FSTSE) and without (HASTE). Magnetic resonance imaging examinations at 1.5 T using T1-weighted IP and OP-GRE with fast low angle shot (FLASH) technique, and T2-weighted FSTSE, T2-weighted HASTE of 137 patients undergoing evaluation for focal liver lesions were reviewed. Five patients were identified in whom CT indicated metastatic disease; however, no liver malignancy was finally proven. Diagnosis was confirmed by biopsy (n = 3), additional wedge resection (n = 1) or follow-up MRI 6–12 months later (n = 5). Regarding the identified five patients, the number of focal liver lesions was 2 (n = 2) and more than 20 (n = 3). The MR imaging characteristics were as follows: OP-image: markedly hypointense (n = 5); IP image: isointense (n = 2) or slightly hyperintense (n = 3); T2-weighted FSTSE-image: isointense (n = 5); T2-weighted HASTE image isointense (n = 1); slightly hyperintense (n = 4). On OP images all lesions were sharply demarcated and of almost spherical configuration (n = 5). Further evaluation by histology or follow-up MR imaging did not give evidence of malignancy in any case. Histology revealed fatty infiltration of the liver parenchyma in three patients. Magnetic resonance follow-up showed complete resolution in two patients and no change in three patients. Multifocal nodular fatty infiltration can simulate metastatic disease on both CT and MR imaging. The combination of in-phase (IP) and opposed-phase (OP) gradient-echo imaging can reliably differentiate MNFIL from metastatic disease. Received: 15 September 1999 Revised: 3 February 2000; Accepted: 7 February 2000     

MRI gadolinium enhancement of bone marrow: age-related changes in normals and in diffuse neoplastic infiltration

 Objective: To quantify gadolinium-related enhancement in the bone marrow of the spine in normals and in patients with homogeneous diffuse malignant bone marrow infiltration. Design and patients: The patients consisted of two groups: group 1 comprised 94 healthy adults (18–86 years) without bone marrow disease and group 2 comprised 30 patients with homogeneous diffuse malignant bone marrow infiltration due to myeloma (n=20) or breast carcinoma (n=10). All patients received intravenous gadopentetate dimeglumine (Gd-DTPA), 0.1 mmol/kg body weight. Pre- and postcontrast signal intensity (SI) on T1-weighted spin-echo (SE) images (TR/TE: 572 ms/15 ms) was measured over a region of interest (ROI) and the percentage SI increase was calculated. The results were confirmed by bone marrow biopsy (n=20) and clinical parameters (n=10). Dynamic contrast-enhanced studies using a spoiled gradient-recalled-echo (GRE) sequence (TR/TE/α: 68 ms/6 ms 75°) were performed in 10 controls with normal bone marrow. Results and conclusion: Contrast material enhancement in healthy persons can vary greatly (range 3–59%, mean 21%, SD 11%). With increasing age there is a significant decrease in contrast enhancement (Pearson’s correlation, P<0.01). The percentage SI increase in patients with intermediate-grade (biopsy 20–50 vol%) and high-grade (biopsy >50 vol%) diffuse malignant bone marrow infiltration was significantly higher than in normals (mean 67%, SD 34%, P<0.001). Low-grade (biopsy <20 vol%) diffuse malignant bone marrow infiltration can not be assessed by non-enhanced T1-weighted SE images or Gd-DTPA application. In conclusion, contrast material enhancement in healthy persons can vary greatly and is dependent on age, while intermediate-grade and high-grade diffuse malignant bone marrow infiltration can be objectively assessed with SI measurements.     

Non-invasive detection of liver fibrosis: Is superparamagnetic iron oxide particle-enhanced MR imaging a contributive technique?

The purpose of our study was to evaluate the ability of superparamagnetic iron oxide (SPIO)-enhanced MR imaging to detect liver fibrosis in patients with chronic liver disease and to compare the findings with histopathological data. Sixty-seven patients with chronic hepatitis (n=58) or focal nodular hyperplasia (FNH; n=9) were studied using a 1.5-T MR system. The protocol included proton density-weighted, T2-weighted spin-echo (SE) and fast SE (FSE) sequences before and after SPIO administration and T2*-weighted gradient-recalled-echo (GRE) sequences after SPIO. Pre- and post-contrast T2-weighted and T2*-weighted sequences were retrospectively evaluated by three independent observers for evidence of non-tumor hypersignal intensities. Three liver patterns were considered: thick reticulations; thin reticulations; and/or multiple areas of hypersignal intensities. Unenhanced or enhanced patterns were compared with histopathological specimens, which had been obtained by percutaneous biopsy of the right lobe within a maximum of 12 months of MR examination. Liver fibrosis was histologically graded using a five-level scale (F0–F4), according to the METAVIR classification. Histopathology demonstrated significant fibrosis (F2–F4) in 57 patients, non-significant fibrosis in 1 patient (F1), and normal liver surrounding FNH in 9 patients (F0). After SPIO administration, at least one pattern of non-tumor hypersignal intensities was seen in 43 (76%) of the 57 patients with F≥2 with good agreement (kappa=0.68) compared with 2 (20%) of the 10 F0/1 patients (p<0.01). Attenuated non-homogeneous liver-signal intensities with persistent thick reticulations, thin reticulations, or multiple areas of hypersignals were observed in, respectively, 30, 52, and 56% of patients with F≥2 with moderate agreement (kappa=0.51). Before SPIO, MR images were positive in 21 of 57 (37%) F≥2 and zero F0/1 patients. Post-contrast proton-density-weighted and T2*-weighted GRE were the most sensitive sequences for detecting non-tumor hypersignal intensities. In patients with chronic liver diseases, SPIO-enhanced MR imaging exhibits non-tumor hypersignal intensities indicative of liver fibrosis by decreasing the signal from the non-fibrotic areas where Kupffer cells are present. Electronic Publication     

A comparison of pulse sequences in the detection of post-traumatic bone marrow abnormalities at low field strength MRI

Objective and patients. One hundred and forty-one patients with recent joint trauma, aged 12–71 years, were imaged on a 0.2-T dedicated MRI system and evaluated for bone bruises. The most beneficial sequences were compared. Design. The diagnosis of post-traumatic bone marrow abnormalities was established in 20 of 141 patients on the basis of decreased signal intensity on T1-weighted SE and GRE sequences and increased signal intensity on T2-weighted TSE and fat-suppressed IRGE sequences. Signal changes within the bone marrow were evaluated and statistically correlated with normal bone. Results. The highest signal alteration was found on T1-weighted SE and GRE sequences, followed by IRGE, which detected smaller differences in signal intensity. T2-weighted TSE imaging showed the least contrast. The areas with bone marrow changes were approximately equal in size on T1-weighted SE and T2-weighted TSE sequences. The same areas depicted on IRGE and GRE sequences proved to be significantly larger (P<0.01). Conclusion. Using a 0.2-T dedicated system T1-weighted SE, T1-weighted GRE and IRGE sequences were most effective in detecting conspicuous bone marrow alteration, while the T2-weighted TSE sequence was inferior. GRE and IRGE imaging showed areas about 4 times larger depicting bone marrow changes. On suspicion of bone bruise, a protocol including GRE and IRGE pulse sequences could be most beneficial.     

Correlation between water content and magnetization transfer ratio of the water component in bone marrow using gradient-echo imagings: normal case study

Objective. To determine the correlation between water content and magnetization transfer (MT) ratio of the water component in normal bone marrow using gradient-echo (GRE) magnetic resonance (MR) imaging. Design. Three types of GRE sequence – using fat suppression, using a combination of MT and fat suppression techniques, and without MT or fat suppression – were performed in nine healthy subjects. The water content of bone marrow assessed with GRE imaging was compared with that assessed with MR spectroscopy in three cases. The correlation between water content and MT ratio was observed using GRE imaging in nine subjects. Results and conclusions. The water content as assessed by GRE imaging and by MR spectroscopy were closely correlated (P<0.005, r=0.932). An inverse correlation between water content and MT ratio was observed in normal bone marrow (P<0.03, r=–0.432), which suggests that the water component in bone marrow includes free water protons.     

Performance of Gd-EOB-DTPA and superparamagnetic iron oxide particles in the detection of primary liver cancer: A comparative study by alternative free-response receiver operating characteristic analysis

The performance of gadolinium-ethoxybenzyl-dieth-ylenetriaminepentaacetic acid (Gd-EOB-DTPA) and superparamagnetic iron oxide (SPIO) particles in detecting liver cancer was compared using alternative free-response receiver operating characteristic (AFROC) analysis, which allowed observers to indicate both the confidence level and the locations of all perceived abnormalities. Axial T1-weighted MR images (1.5 T) pre/post Gd-EOB-DTPA (25 μmol/kg) injection were obtained for 12 rats with chemically induced liver tumors (64 tumors). T2-weighted images (T2WI) were obtained pre/post SPIO (10 μmol/kg) injection for the same animal. Liver signal-to-noise ratio (SNR), tumor-liver contrast-to-noise ratio (CNR), and histopathologic sections corresponding to MR images were obtained. In AFROC, the location and the confidence level for each tumor were indicated independently on MR images by four radiologists. By plotting true-positive fraction and probability of false-positive per image, the area under the AFROC curve (A1) was estimated and statistically analyzed between each sequence. Either drug significantly improved tumor-liver CNR (P < .001) and tumor detection (diameter ≤ 6 mm; P < .05). Gd-EOB-DTPA significantly (P < .05) improved the A1 in T1WI. There was no A1 difference between T2WI + SPIO and T1WI + Gd-EOB-DTPA. Gd-EOB-DTPA-enhanced T1WI showed the same performance as SPIO-enhanced T2WI in detecting liver tumors.     

Bone marrow response in treated patients with Gaucher disease: evaluation by T1-weighted magnetic resonance images and correlation with reduction in liver and spleen volume

Purpose. To determine whether T1-weighted magnetic resonance (MR) images can demonstrate response in the marrow of patients with type 1 Gaucher disease treated with enzyme replacement therapy (ERT) and to determine whether a relationship exists between liver and spleen volume reductions and visible marrow changes. Patients. Forty-two patients with type 1 Gaucher disease were evaluated on at least two occasions. Thirty-two patients received ERT. Of these patients, 15 had a baseline examination prior to the initiation of ERT. The remaining 10 patients did not receive ERT. Design. T1-weighted and gradient recalled echo (GRE) coronal images of the femurs and hips were obtained. Concurrently, liver and spleen volumes were determined using contiguous breath-hold axial gradient-echo images. T1-weighted images of the hips and femurs were evaluated to determine change or lack of change in the yellow marrow. Results. Of the 32 patients receiving ERT, 14 (44%) demonstrated increased signal on T1-weighted images suggesting an increase in the amount of yellow marrow. If only the 15 patients with a baseline examination were considered, the response rate to ERT was 67%. Using Student’s t-test a highly significant correlation (P<0.005) was found between marrow response and reduction in liver and spleen volume. Conclusions. Marrow changes in patients receiving ERT can be detected by T1-weighted images. This response correlated with reductions in visceral volumes (P<0.0005). Received: 11 April 2000 Revision requested: 18 July 2000 Revision received: 26 July 2000 Accepted: 27 July 2000     

MRI of bone marrow disorders

Four factors can be used in MR of bone marrow: fat–water distribution, artifacts induced by bone trabeculae, diffusion, and uptake of contrast media. Fat–water is imaged using T1-weighted spin-echo, short tau inversion recovery (STIR), and fast STIR, in- and out-of-phase gradient echo, and fat pre-saturation sequences; bone trabeculae by gradient echo with long TE; diffusion by single-shot spin-echo. The injection of contrast media is a more easy and efficient way to improve the specificity. The value and limitations of those sequences are discussed in marrow replacements (metastases, lymphoma, leukemia) and in myeloid hyperplasia or depletion.     

Liver tumors in cirrhosis: experimental study with SPIO-enhanced MR imaging

The influence of cirrhosis on superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging of the liver was studied in 31 rats. Experimental models included carbon tetrachloride-induced cirrhosis and liver engrafting of rhabdomyosarcoma S4T cells. Hepatic uptake of SPIO measured with relaxometry decreased dramatically with histologic grade, while splenic uptake increased; the same results were achieved by calculating K values. Imaging of 13 tumorous cirrhotic rats confirmed these results by showing a muted decrease in liver signal intensity on spin-echo images after injection of SPIO. Nevertheless, all intrahepatic tumors could be visualized, as confirmed by postmortem examination. On gradient-echo images, postinjection contrast between the tumor and the liver was not affected by cirrhosis. Thus, despite strong impairment of hepatic uptake in cirrhosis, the diagnostic efficacy of MR imaging with SPIO did not seem to be significantly affected.     

Assessment of cartilage-dedicated sequences at ultra-high-field MRI: comparison of imaging performance and diagnostic confidence between 3.0 and 7.0 T with respect to osteoarthritis-induced changes at the knee joint

Objective  The objectives of the study were to optimize three cartilage-dedicated sequences for in vivo knee imaging at 7.0 T ultra-high-field (UHF) magnetic resonance imaging (MRI) and to compare imaging performance and diagnostic confidence concerning osteoarthritis (OA)-induced changes at 7.0 and 3.0 T MRI. Materials and methods  Optimized MRI sequences for cartilage imaging at 3.0 T were tailored for 7.0 T: an intermediate-weighted fast spin-echo (IM-w FSE), a fast imaging employing steady-state acquisition (FIESTA) and a T1-weighted 3D high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) sequence. Three healthy subjects and seven patients with mild OA were examined. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diagnostic confidence in assessing cartilage abnormalities, and image quality were determined. Abnormalities were assessed with the whole organ magnetic resonance imaging score (WORMS). Focal cartilage lesions and bone marrow edema pattern (BMEP) were also quantified. Results  At 7.0 T, SNR was increased (p < 0.05) for all sequences. For the IM-w FSE sequence, limitations with the specific absorption rate (SAR) required modifications of the scan parameters yielding an incomplete coverage of the knee joint, extensive artifacts, and a less effective fat saturation. CNR and image quality were increased (p < 0.05) for SPGR and FIESTA and decreased for IM-w FSE. Diagnostic confidence for cartilage lesions was highest (p < 0.05) for FIESTA at 7.0 T. Evaluation of BMEP was decreased (p < 0.05) at 7.0 T due to limited performance of IM-w FSE. Conclusion  Gradient echo-based pulse sequences like SPGR and FIESTA are well suited for imaging at UHF which may improve early detection of cartilage lesions. However, UHF IM-w FSE sequences are less feasible for clinical use.     

MRI in focal liver disease: A comparison of small and ultra-small superparamagnetic iron oxide as hepatic contrast agents

The purpose of this study was to compare small and ultrasmall superparamagnetic iron oxide particles (SPIO and USPIO, respectively) as MR contrast agents for the evaluation of focal hepatic disease. In two different patient groups (SPIO [n = 53], USPIO [n = 27]), with focal liver disease (metastases, hepatocellular carcinoma [HCC], hepatocellular adenoma [HCA], and focal nodular hyperplasia [FNH]), spin-echo T1- and T2-weighted images (T1WI, T2WI) were obtained at 1.0T, before and after intravenous contrast administration. The percentage signal-to-noise ratio (SNR) change and lesion-to-liver contrast (LLC) were measured and statistically compared. The liver decreased in signal intensity (SI) after SPIO administration (?28%) and increased after USPIO administration (+16%) on T1WI. On T2WI, the liver decreased in SI on postcontrast images with both agents (?78% SPIO, ?73% USPIO). This difference was not statistically significantly different (P ? .07). Both SPIO and USPIO provided >500% improvement in LLC on T2WI. On T1WI, LLC was increased in metastases (120%) and HCC (325%) with SPIO. Post-USPIO, LLC was increased on T1WI only in metastases (>500%). Both SPIO and USPIO show excellent hepatic uptake, presumed secondary to reticuloendothelial activity, based on the degree of %SI change seen in the liver after administration of contrast on T2WI. However, USPIO preparations exhibit blood pool activity that may aid in further characterization of focal liver lesions, as is evidenced by their greater T1 effect in the liver and in some focal liver lesions.     

Gadolinium-enhanced MR imaging of the wrist in rheumatoid arthritis: value of fat suppression pulse sequences

 Objective. To determine the usefulness of fat-suppressed gadolinium (Gd)-enhanced MR imaging of the wrist in patients with rheumatoid arthritis (RA). Design and patients. Fat-suppressed Gd-enhanced T1-weighted spin-echo (SE) images were obtained and compared with other standard techniques in 38 wrists of 27 patients (22–77 years) with RA. Scoring based on the degree of synovial enhancement of each joint was developed and the total scores (J-score) were correlated with radiographic stage, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and symptomatic change in the follow-up study. Results. Synovial proliferations showed marked enhancement in all the wrists. In addition, contrast enhancement in the bone marrow and tenosynovium was seen in 36 and eight wrists respectively. Fat-suppressed Gd-enhanced T1-weighted images demonstrated these abnormalities better than other techniques. The J-scores correlated well with values of CRP (P=0.0034), but not with radiographic stages and ESR. Conclusion. Fat-suppressed Gd-enhanced T1-weighted SE images can clearly demonstrate most of the essential lesions in RA including the proliferative synovium, bone erosion, bone marrow inflammatory change, and tenosynovitis. Scoring based on the extent of Gd-enhancement of synovium can be useful in the assessment of the inflammatory status.     

MRI in the diagnosis of small bowel disease: use of positive and negative oral contrast media in combination with enteroclysis

The aim of the study was to evaluate the additional findings of MRI following small bowel enteroclysis and to compare the efficacy of negative and positive intraluminal contrast agents. Fifty patients with inflammatory or tumorous small bowel disease were investigated by small bowel enteroclysis and consecutive MRI using breathhold protocol (T1-weighted fast low-angle shot, T2-weighted turbo spin echo). Patients were randomly assigned to either receiving a positive oral (Magnevist, Schering, Berlin, Germany) or a negative oral MR contrast media (Abdoscan, Nycomed, Oslo, Norway). The pattern of contrast distribution, the contrast effect, presence of artifacts, as well as bowel wall and extraluminal changes, were determined and compared between the contrast type using Fischer's exact test. Sensitivity, specificity, and diagnostic accuracy for MRI and enteroclysis were calculated. Twenty-seven patients had clinically proven Crohn's disease and two patients surgically proven small bowel tumours. Magnetic resonance imaging had important additional findings as abscesses and fistulae in 20 patients. Surgically compared sensitivities were 100 and 0 % for MRI and enteroclysis, for the detection of abscesses, and 83.3 and 17 % for the diagnosis of fistulae, respectively. Bowel wall thickening was more reliably detected with use of positive oral contrast media without intravenous enhancement (p < 0.001), whereas postcontrast negative oral contrast media allow for a superior detection (p < 0.001). T2-weighted sequences were necessary with use of negative oral contrast media, because loop abscesses may be masked. Magnetic resonance imaging should be performed in all patients with suspicion of extraintestinal complications, because the complications are more reliably detected by MRI. Negative oral contrast media show advantages with the use of intravenous contrast but can mask loop abscesses using only T1-weighted imaging. Received: 5 March 1999; Revised: 21 September 1999; Accepted: 3 February 2000     

Blueberry juice used per os in upper abdominal MR imaging: composition and initial clinical data

The aim of this study was to evaluate the use of a commercially available blueberry juice (BJ) both as a positive and negative oral contrast agent and to present the exact contents of paramagnetic ions. The concentration of Mn and Fe were determined in tinned myrtilles in syrup (atomic absorption). Nine healthy volunteers and 12 patients (age range 20–65 years) were examined using a 1-T MR scanner before and after per os administration of 430 ml of BJ. A qualitative analysis of signal alterations in the stomach, duodenum, and proximal small intestine was performed. In addition, a quantitative analysis was assessed in terms of signal-to-noise ratio calculation. The mean concentration ( ×± SD) of the ions found in the content of the three cans were 3.3 ± 0.4 μg/g for iron and 20.6 ± 2.6 μg/g for manganese. Based on the qualitative evaluation, signal alteration on T1-weighted images after administration of BJ was statistically significant in the stomach and duodenum, but not in the proximal small bowel. Signal alteration on T2-weighted images was not statistically significant in any part of the gastrointestinal tract. The quantitative analysis of the T1- and T2 shortening showed that BJ is efficient with only T1-weighted sequences, and this applied to the stomach, duodenum, and proximal small bowel. Blueberry juice can be used as an oral contrast agent in upper abdominal MR for T1-weighted imaging. Received: 7 September 1999; Revised: 29 November 1999; Accepted: 16 February 2000     

MRI of degenerative bone marrow lesions in experimental osteoarthritis of canine knee joints

 Objective. The objective of this study was to determine the value of MRI in the detection of degenerative bone marrow abnormalities in an animal osteoarthritis model. Design. In 10 dogs with experimentally induced unilateral osteoarthritis of the knee, MRI was performed using two-dimensional spin-echo (2D-SE) and three-dimensional gradient-echo (3D-GE) imaging. Contrast enhanced T1-weighted 2D-SE sequences were also obtained after injection of gadolinium-DTPA. The results were compared with the gross and histopathologic findings and with radiography. Results. Histopathologic specimens revealed 21 osteosclerotic lesions and 5 intraosseous cysts. On 2D-SE images, 24 of 26 lesions were detected, while 21 of 26 lesions were identified on 2D-GE sequences. Radiography, including conventional tomography, demonstrated 9 of 26 lesions. Regardless of the sequence weighting, all osteosclerotic lesions appeared hypointense on MRI. Signal loss in bone sclerosis resulted primarily from the reduction of intact fat marrow, the increased bone density being of secondary importance. Quantitative signal analysis allowed approximate estimation of the grade of sclerosis. On postcontrast images, sclerotic bone remained hypointense, although significant but non-specific enhancement relative to the normal fat marrow was observed. The extent of contrast enhancement did not correlate with the grade of osteosclerosis. All five cysts were readily diagnosed by MRI. Cysts displayed either central or marginal contrast enhancement within their cavities. Conclusions. MRI provides a sensitive method for the diagnosis of osteoarthritic bone abnormalities, allowing their differentiation from most non-degenerative subarticular lesions.     

Liver,bone marrow,pancreas and pituitary gland iron overload in young and adult thalassemic patients: a T2 relaxometry study

Thirty-seven patients with β-thalassemia major, including 14 adolescents (15.2 ± 3.0 years) and 23 adults (26.4 ± 6.9 years), were studied. T2 relaxation time (T2) of the liver, bone marrow, pancreas and pituitary gland was measured in a 1.5-Tesla magnetic resonance (MR) imager, using a multiecho spin-echo sequence (TR/TE 2,000/20, 40, 60, 80, 100, 120, 140, 160 ms). Pituitary gland height was evaluated in a midline sagittal scan of a spin-echo sequence (TR/TE, 500/20 ms). The T2 of the pituitary gland was higher in adolescents (59.4 ± 15 ms) than in adults (45.3 ± 10.4 ms), P < 0.05. The T2 of the pancreas was lower in adolescents (43.6 ± 10.3 ms) than in adults (54.4 ± 10.4 ms). No difference among groups was found in the T2 of the liver and bone marrow. There was no significant correlation of the T2 among the liver, pancreas, pituitary gland and bone marrow. There was no significant correlation between serum ferritin and T2 of the liver, pancreas and bone marrow. Pituitary T2 showed a significant correlation with pituitary gland height (adolescents: R = 0.63, adults: R = 0.62, P < 0.05) and serum ferritin (adolescents: R = −0.60, adults: R = −0.50, P < 0.05). In conclusion, iron overload evaluated by T2 is organ specific. After adolescence, age-related T2 changes are predominantly associated with pituitary siderosis and fatty degeneration of the pancreas. Pituitary size decreases with progressing siderosis.