Renal carcinoma: diagnosis of venous invasion with Gd-enhanced MR venography

The aim of this study was to evaluate the usefulness of gadolinium-enhanced time-of-flight magnetic resonance venography (MRV) in the diagnosis of bland thrombosis/tumoral invasion in the preoperative assessment of renal cell carcinoma. Preoperative precontrast and enhanced GRE fast low-angle shot (FLASH) images of 36 patients with renal adenocarcinoma were reviewed and compared with pre- and post-contrast T1-weighted images. All patients underwent surgery, and MR findings were blindly and prospectively compared with surgical and pathologic data, considered the standard. Renal vein and vena cava were involved in 17 and 9 patients, respectively; right atrial extension was present in one patient. Precontrast spin-echo (SE) and FLASH images were 88 % sensitive and 100 % specific in the detection of venous involvement, respectively, and enhanced FLASH images 100 % sensitive and 96 % specific. The nature of thrombus (neoplastic or bland) was more accurately assessed (McNemar's, p < 0.05) with FLASH-enhanced MR images (sensitivity 89 %; specificity 96 %) than with SE and precontrast FLASH images (sensitivity 79 %; specificity 94 %). Our data suggest that use of Gd-enhanced MRV might improve preoperative assessment of vascular involvement in renal carcinoma. Received: 7 September 1999; Revised: 26 November 1999; Accepted: 26 November 1999     

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     

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     

Fat-suppressed fast spin-echo mid-TE (TE[effective]=34) MR images: comparison with fast spin-echo T2-weighted images for the diagnosis of tears and anatomic variants of the glenoid labrum

Objective. To compare the sensitivity, specificity, and accuracy of fat-suppressed fast spin-echo (FSE) mid-TE (TE[effective]=34) images with fat-suppressed FSE T2-weighted images for the diagnosis of labral abnormalities. Design and patients. The study included 27 consecutive patients who had axial fat-suppressed FSE T2-weighted and fat-suppressed FSE mid-TE MR images, and had labral abnormalities diagnosed at arthroscopy. The acquisition time was about 5 min for each sequence, but the mid-TE sequence allowed a higher spatial resolution than the T2-weighted images (256×256 versus 256×192). Twenty-eight age-matched patients with arthroscopically normal labra were included as a control group. The labrum was graded on the MR images as normal or abnormal separately by two musculoskeletal radiologists who were masked to the history and arthroscopic results. The surgical findings were used as the gold standard for calculating the sensitivity, specificity, and accuracy for interpreting the correct location of a labral abnormality. The sensitivity, specificity, and accuracy for the two sequences were compared with a McNemar test, and significance defined as P<0.05. Results. For observer 1, the sensitivity for labral abnormalities was 0.59 on the T2-weighted images, and 0.78 on the mid-TE images (P=0.12). The specificity was 0.54 for the T2-weighted, and 0.64 for the mid-TE images (P=0.51). The accuracy was 0.56 for the T2-weighted, and 0.71 for the mid-TE images (P=0.08). For observer 2, the sensitivity/specificity/accuracy was 0.67/0.93/0.80 for the T2-weighted, and 0.70/0.86/0.78 for the mid-TE images (all P>0.5). Conclusion. In this small study there is no statistically significant difference for demonstrating labral abnormalities between FSE T2-weighted images, and higher-resolution fat-suppressed FSE mid-TE (TE[effective]=34) images obtained with a similar acquisition time. Although there was a general trend toward higher sensitivity and accuracy with the mid-TE sequence, particularly for one of the two observers, a larger study is needed to determine whether this is the preferred single axial pulse sequence for conventional MR imaging of the labrum. Received: 28 June 1999 Revision requested: 9 September 1999 Revision received: 20 September 1999 Accepted: 28 September 1999     

Effect of superparamagnetic iron oxide on bone marrow

The goal of this study was to compare the effects of SPIO particles on the signal intensity of the bone marrow of the vertebra spine in patients with and without liver cirrhosis. Forty-eight patients with normal liver tissue and 56 patients with liver cirrhosis were examined before and after intravenous SPIO administration, using a 1.5-T system (Magnetom Vision, Siemens, Erlangen, Germany) with a semiflexible cp-array coil. Three different pulse sequences were applied: 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 ratio (SNR) of the liver, vertebra bone and paraspinal muscle were obtained. The SNR value change in each patient group and the SNR value difference between the two groups were evaluated. For assessment of statistical significance, Student's t-test with a level of p < 0.05 was applied. No significant differences in the SNR values of the liver and bone marrow between the two groups could be seen with any of the three sequences precontrast. Using the T1-weighted gradient-echo sequence in the noncirrhotic liver group, pre- and postcontrast comparisons of the SNR values of the liver and bone marrow indicated a decrease of approximately –44.3 % (p = 0.02) and increase of approximately 15.3 % (p = 0.04), respectively. No significant change was seen in the cirrhotic liver group. With the T2-weighted fast spin-echo sequence, a significant decrease of the SNR value of the liver and the bone marrow in both groups was seen. With the T2^*-weighted gradient-echo sequence, the signal intensity decrease of the normal liver tissue was approximately –65.6 % (p = 0.00), in cirrhotic liver tissue the decrease was –29.9 % (p = 0.02). The SNR values of the bone marrow showed a decrease of –27.8 % (p = 0.04) in the noncirrhotic liver group, whereas in the cirrhotic liver group it was only –11.3 % and statistically not significant. The effect of SPIO particles on the liver and bone marrow is significantly less in patients with liver cirrhosis. Received: 2 April 1999; Revised: 5 October 1999; Accepted: 2 February 2000     

Imaging in ureteral complications of renal transplantation: value of static fluid MR urography

Ureteral obstruction is an infrequent complication after renal transplantation that may cause rapid loss of transplant function. We tested static fluid MR urography for determining the cause of graft hydronephrosis. Magnetic resonance urography was performed in nine transplants with dilated collecting systems on ultrasound. A heavily T2-weighted 3D turbo spin-echo sequence on a 1.5-T scanner was used and maximum intensity projections were obtained. The patients also underwent excretory urography (n = 1), renal scintigraphy (n = 1), antegrade pyelography (n = 3), voiding cystourethrography (n = 4), and non-enhanced CT (n = 2). Six patients had pathologic conditions including ureteral stricture, compression by lymphoceles, implantation stenosis, vesicoureteral reflux, and late-occurring transitional cell carcinoma at the implantation site. Static MRU was able to diagnose or exclude a dilation of the graft collecting system. It visualized the course of the ureters and localized the obstruction site in four of five obstructed transplants. In one case the ureter was obscured by lymphoceles, which were demonstrated by hydrographic MRU as well. The definite cause for obstruction was provided in only 2 of 5 cases. Dilation due to vesicoureteral reflux could not be differentiated. The current multimodality approach to renal transplant imaging already provides comprehensive assessment of graft hydronephrosis. Static MRU may be useful in some cases since complications associated with intravenous iodinated contrast or antegrade pyelography can be avoided. Its main drawback, the lack of functional information, may be overcome by combining it with contrast-enhanced MRU. Received: 18 February 1999; Revised: 23 July 1999; Accepted: 18 November 1999     

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     

Axillary lymph node metastases in breast cancer: preoperative detection with dynamic contrast-enhanced MRI

Metastatic involvement of axillary lymph nodes is one of the most important prognostic variables in breast cancer. The aim of our work was to study the value of dynamic contrast-enhanced MR imaging in revealing axillary lymph node metastases from breast cancer. A total of 65 patients with invasive breast cancer treated with axillary lymph node dissection were preoperatively evaluated by MRI. T1-weighted dynamic contrast-enhanced 3D images were acquired using a coil covering the breast and the axilla. The dynamic contrast enhancement, size, and morphology of the axillary lymph nodes were registered. Histopathological examination revealed axillary lymph node metastases in 24 patients. When using a signal intensity increase in the lymph nodes of > 100 % during the first postcontrast image as a threshold for malignancy, 57 of 65 patients were correctly classified (sensitivity 83 %, specificity 90 %, accuracy 88 %). These results were not improved when lymph node size and morphology were used as additional criteria. Axillary lymph nodes can be evaluated as a part of an MR-mammography study without substantial increase in examination time, and provide the surgeon with knowledge about the localization of possible metastatic lymph nodes. Received: 25 February 1999; Revised: 3 August 1999; Accepted: 27 January 1999     

MR arthrography of the shoulder: comparison of low-field (0,2 T) vs high-field (1.5 T) imaging

The objective of this study was to compare the image quality, sensitivity, specificity, and diagnostic accuracy of an open low-field MR system (0.2 T) with a standard high-field MR system (1.5 T) after arthrography of the shoulder. Thirty-eight patients either with suspected chronic instability (n = 12) or rotator cuff abnormalities (n = 26) were examined. Intra-articular injection of diluted Gd-DTPA was followed in randomized order either first by imaging on an open 0.2-T system or on a 1.5-T system. The image material was evaluated independently by two radiologists in a blinded fashion with respect to overall image quality and the detection of rotator cuff as well as capsular and labral abnormalities. Surgical correlation was available in 27 (71 %) of 38 patients. For both systems, sensitivity and specificity for rotator cuff tears were 100 % each, and for labrum pathologies, these values were 100 and 93 %, respectively. The agreement for detection of labral pathologies between low-field and high-field examinations was good (ϰ = 0.69, ϰ = 0.61). For the detection of full-thickness tears of the rotator cuff, the agreement between the low-field and high-field MR examinations was very good and significant (ϰ = 0.94, ϰ = 1, p < 0.001). Overall image quality was rated good in 17 (45 %) and fair in 21 (55 %) of 38 cases on the 0.2-T MR system, and good in 32 (84 %) and fair in 6 (16 %) of 38 cases on the 1.5-T system. Motion artifacts were considered low in 24 (63 %) and moderate in 14 (37 %) of 38 cases for the 0.2-T system and low in 34 (89 %) and moderate in 4 (11 %) for 1.5-T system. Based on our results, low-field MR compares favorably to high-field MR in the detection of major abnormalities of the glenohumeral joint, at least when MR arthrography is used. Disadvantages are the duration of the examination and thus the risk of reduced image quality caused by motion artifacts. Received: 14 July 1999; Revised: 27 December 1999; Accepted: 27 December 1999     

Accuracy of T2-weighted fast spin-echo MR imaging with fat saturation in detecting cartilage defects in the knee: comparison with arthroscopy in 130 patients

OBJECTIVE: The purpose of this study was to assess the accuracy of routine T2-weighted MR imaging in detecting and grading articular cartilage lesions in the knee compared with arthroscopy. SUBJECTS AND METHODS: We examined 130 consecutive patients who underwent MR imaging and arthroscopy of the knee for suspected internal derangement. MR imaging consisted of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequences. Each single plane was evaluated and graded for the presence and appearance of articular cartilage defects using a standard arthroscopic grading scheme adapted to MR imaging. RESULTS: Of the 86 arthroscopically proven abnormalities, 81 were detected on MR imaging. Sensitivity of the T2-weighted fast spin-echo sequence with fat saturation was 61% for the coronal plane alone and 59% for the axial plane alone. Specificity for each plane was 99%. Sensitivity for the sagittal T2-weighted spin-echo sequence was 40%, and specificity was 100%. Sensitivity of the combination of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequence compared with arthroscopy for revealing cartilage lesions was 94%, specificity was 99%, and accuracy was 98%. Sensitivity of coronal and axial T2-weighted fast spin-echo sequences with fat saturation was 93%, and specificity was 99%. Fifty-five lesions (64%) were identically graded on MR imaging and arthroscopy. Seventy-eight lesions (90%) were within one grade using MR imaging and arthroscopy, and 84 lesions (97%) were within two grades using MR imaging and arthroscopy. CONCLUSION: T2-weighted fast spin-echo MR imaging with fat saturation is an accurate and fast technique for detecting and grading articular cartilage defects in the knee. The combination of the axial and coronal planes offers sufficient coverage of articular surfaces to provide a high sensitivity and specificity for chondral defects.     

X-linked adrenoleukodystrophy: the role of contrast-enhanced MR imaging in predicting disease progression

BACKGROUND AND PURPOSE: Early assignment of disease progression among patients with X-linked adrenoleukodystrophy (ALD) is critical for the appropriate selection of effective therapy. We evaluated the association between contrast enhancement on T1-weighted spin-echo MR images and disease progression. METHODS: Clinical charts of patients with X-linked ALD were reviewed for age, availability of MR images of the brain, severity of neurologic impairment, and duration and number of follow-up evaluations. Forty-three male patients with X-linked ALD had undergone multiple MR imaging examinations of the brain that consisted of at least sagittal and axial T1-weighted spin-echo, axial double-echo spin-echo, and contrast-enhanced axial T1-weighted spin-echo imaging. The MR images were reviewed for the presence of contrast enhancement. In addition, global disease burden, as shown by the double-echo spin-echo images, was assessed using a visual scoring method (Loes score). RESULTS: Enhancement was seen on the initial T1-weighted spin-echo MR images of 21 (49%) patients; 18 (86%) of the 21 patients had disease progression revealed by the follow-up evaluations based on MR imaging (Loes) and neurologic scores. No enhancement was seen on the initial T1-weighted spin-echo MR images of 22 (51%) patients; for 18 (82%) of the 22 patients, no evidence of disease progression was revealed by the follow-up evaluations. CONCLUSION: There is a very strong association between the presence of contrast enhancement on T1-weighted MR images and X-linked ALD progression based on clinical evaluation and MR imaging.     

Choledocholithiasis: repetitive thick-slab single-shot projection magnetic resonance cholangiopancreaticography versus endoscopic ultrasonography

This prospective study compares repetitive thick-slab single-shot projection magnetic resonance cholangiopancreatography (MRCP) with endoscopic ultrasonography (EUS) for the detection of choledocholithiasis. Fifty-seven consecutive patients (36 women, mean age 61) referred for suspected choledocholithiasis underwent MRCP, followed by EUS. Each procedure was performed by different operators blinded to the results of the other investigation. MR technique included a turbo spin-echo T2-weighted axial sequence with selective fat saturation (SPIR/TSE, TE=70 ms, TR=1,600 ms), followed by coronal dynamic MRCP. The same thick-slab slice was sequentially acquired 12 times as breath-hold single-shot projection imaging (SSh, TE=900 ms, TE=8,000 ms) centred on the common bile duct (CBD). Two experienced radiologists independently and blindly evaluated MR images for the detection of CBD stones. Their inter-observer agreement kappa was determined. Secondly, the two observers read MR images in consensus again. CBD stones were demonstrated in 18 out of 57 patients (31.6 %) and confirmed by endoscopic retrograde cholangiography (ERCP, n=17) or intraoperative cholangiography (n=1). Clinical follow-up served as the “gold standard” in patients with negative results without following invasive procedure (n=28). Sensitivity, specificity, accuracy, positive and negative predictive value for MRCP resulting from consensus reading were 94.9%, 94.4%, 94.7%, 97.4% and 89.5%, respectively. Corresponding values of EUS were 97.4%, 94.4%, 96.5%, 97.4% and 94.4%. Inter-observer agreement kappa was 0.81. Repetitive thick-slab single-shot projection MRCP is an accurate non-invasive imaging modality for suspected choledocholithiasis and should be increasingly used to select those patients who require a subsequent therapeutic procedure, namely ERCP.     

MR Imaging features of pelvic mucinous carcinomas

Mucinous carcinomas in the pelvis differ from non-mucinous tumors because of the differences in clinical outcome and imaging appearance. Mucinous rectal carcinomas, for example, are known to be higher in stage at the time of the diagnosis because they are more likely to be infiltrative and show a greater tendency for recurrence. These factors may lead to a poorer prognosis in patients with the mucinous as compared with non-mucinous carcinomas. Mucinous carcinomas of all types typically show high signal intensity on T2-weighted MR images, and therefore mimic other conditions such as necrotic tumors, fluid collections, cysts, or liver hemangiomas. To familiarize readers with the MRI appearance, and to avoid pitfalls, this paper illustrates the MRI features of the mucinous adenocarcinomas in various pelvic organs. Received: 8 February 1999; Revised: 7 October 1999; Accepted: 10 January 2000     

Rapid MRI assessment of renal space-occupying lesions

The aim of this study was to determine whether rapidly acquired MRI sequences, taking less than 5 min imaging time, can accurately characterise renal masses. All patients found to have a renal space-occupying lesion on CT or ultrasound were asked to participate in a prospective study using rapidly acquired MRI. The MRI technique was performed on a GE Signa (General Electric, Milwaukee, Wis.) 1.5 T magnet using breath-hold coronal and axial T1 GRASS (fast spoiled gradient-recalled acquisition into steady state, FSPGR/30/90) and axial T2 fast spin-echo sequences. The results were analysed by two radiologists unaware of the CT or ultrasound findings. The CT/US was independently viewed by a third radiologist. Lesions were characterised as simple cysts, indeterminate or solid. The MR and CT/US results were correlated and the sensitivity and specificity of MR for the characterisation of simple cysts and solid renal masses calculated. A total of 144 lesions (68 patients; 29 women 39 men, age range 32–78 years, average age 60 years) were studied: 111 simple cysts; 3 hyperdense cysts; 26 renal cell carcinomas; and 4 indeterminate lesions on CT/US. There was agreement between the CT/US and MRI in 82 % of cases. All renal cell carcinomas were correctly characterised on MRI. Of simple cysts, 79 % were correctly identified using this technique. Breath-hold MRI performed in less than 5 min can accurately characterise the majority of renal masses. It is 100 % sensitive in the characterisation of renal carcinoma, and it correctly identified approximately 80 % of simple cysts. If used at the time a renal mass is detected on MRI, it would reduce the need for further investigation of the majority of incidentally detected lesions which are simple cysts. Received: 15 December 1998; Revised: 10 May 1999; Accepted: 2 July 1999     

Masses of the tongue and floor of the mouth: findings on magnetic resonance imaging

The purpose of this study was to determine the value of MR imaging for the demonstration of masses in the tongue and floor of the mouth. Nine patients were prospectively examined with MR imaging after physical examination. Imaging protocol included T2 and contrast-enhanced and non-contrast-enhanced T1-weighted turbo spin-echo sequences, and the findings were compared with surgical and histopathological results. Histopathological examination revealed four squamous cell carcinomas, one adenoid cystic carcinoma, two tongue abscesses, and one chronic inflammatory change. The other case was diagnosed as hemangioma depending on clinical and imaging findings alone. In cases with squamous cell carcinoma, staging was done on the basis of MR imaging findings, and was found to be T4 in two cases, T3 in one case, and T2 in another. The primary role of MR imaging of the tongue and oropharynx is not to make a tissue diagnosis. Multiple deep biopsies are mandatory for the differentiation of other inflammatory and neoplastic lesions. Magnetic resonance imaging produces coronal and sagittal image planes to assess the volume and spread of the lesion and helps the surgeon determine the direction in which the biopsy should be performed. Received: 4 October 1999; Revised: 31 January 2000; Accepted: 6 April 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.     

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     

Denervation syndromes of the shoulder girdle: MR imaging with electrophysiologic correlation

Objective. To investigate the use of MR imaging in the characterization of denervated muscle of the shoulder correlated with electrophysiologic studies. Design and patients. We studied with MR imaging five patients who presented with shoulder weakness and pain and who underwent electrophysiologic studies. On MR imaging the distribution of muscle edema and fatty infiltration was recorded, as was the presence of masses impinging on a regional nerve. Results. Acute/subacute denervation was best seen on T2-weighted fast spin-echo images with fat saturation, showing increased SI related to neurogenic edema. Chronic denervation was best seen on T1-weighted spin-echo images, demonstrating loss of muscle bulk and diffuse areas of increased signal intensity within the muscle. Three patients showed MR imaging and electrophysiologic findings of Parsonage Turner syndrome. One patient demonstrated an arteriovenous malformation within the spinoglenoid notch, impinging on the suprascapular nerve with associated atrophy of the infraspinatus muscle. The fifth patient demonstrated fatty atrophy of the teres minor muscle caused by compression by a cyst of the axillary nerve and electrophysiologic findings of an incomplete axillary nerve block. Conclusion. MR imaging is useful in detecting and characterizing denervation atrophy and neurogenic edema in shoulder muscles. MR imaging can provide additional information to electrophysiologic studies by estimating the age (acute/chronic) and identifying morphologic causes for shoulder pain and atrophy. Received: 5 May 1999 Revision requested: 22 July 1999 Revision received: 28 July 1999 Accepted: 29 July 1999     

MRI of spinal hardware: comparison of conventional T1-weighted sequence with a new metal artifact reduction sequence

Objective. This study was designed to compare diagnostic quality of MR images of patients with spinal hardware acquired using a conventional T1-weighted spin-echo sequence and a new metal artifact reduction sequence (MARS). Conclusion. The new MARS sequence effectively reduces the degree of tissue-obscuring artifact produced by spinal fixation hardware and subjectively improves image quality compared with the conventional T1-weighted spin-echo sequence. Received: 30 May 2000 Revision requested: 12 September 2000 Revision received: 27 September 2000 Accepted: 27 November 2000     

Improving postoperative MR imaging of pituitary macroadenomas: comparison of full and reduced dose of gadopentetate dimeglumine

The aim of this study was to evaluate the efficacy of contrast-medium (CM)-enhanced MR imaging of operated pituitary macroadenomas with reduced dose of gadopentetate dimeglumine. In a prospective study 18 patients were examined with coronal T1-weighted MR imaging prior to and following intravenous CM injections. Two sets of contrast-enhanced coronal images were obtained in each patient; the first set after 50 % of the recommended dose of 0.1 mmol/kg body weight (b. w.) had been administered, and the second set immediately after additional CM had been given to make up a total dose of 0.1 mmol/kg b. w. The images were evaluated by three neuroradiologists. The SIPAP classification system was used to evaluate tumour extension, whereas tumour margin conspicuity was scored using an arbitrary scale of 1–5 (1 = indistinct, 5 = well defined). Signal intensity measurements obtained from the most enhancing part of the adenomas demonstrated increased enhancement with increased CM dose. Tumour delineation scores were significantly better on the reduced- and full-dose images than on pre-CM injection images, but, with one exception, tumour extension was identified as the same on all imaging sequences. Postoperative MR imaging of large macroadenoma residues can routinely be performed without intravenous CM. When CM is indicated a reduced dose of gadopentetate dimeglumine should provide sufficient diagnostic information. Received: 29 June 1999; Revised: 2 December 1999; Accepted: 14 March 2000