Assessing venous thrombus in renal cell carcinoma: preliminary results for unenhanced 3D-SSFP MRI

AIM

To test the potential of unenhanced cardiac- and respiratory-motion-corrected three-dimensional steady-state free precession (3D-SSFP) magnetic resonance imaging (MRI) for the assessment of inferior vena cava (IVC) thrombus in patients with clear-cell renal cell carcinoma (cRCC), compared to standard contrast-enhanced (CE)-MRI and CE-computed tomography (CT).

MATERIALS AND METHODS

Eighteen patients with cRCC and IVC thrombus, who received CE-MRI and 3D-SSFP at 1.5 T between June 2015 and December 2017, were included. The diagnostic performance of 3D-SSFP in determining the level of thrombus extension, contrast-to-noise ratio (CNR), and image quality were compared with standard MRI/CT and validated against intraoperative and histopathology results.

RESULTS

There was 100% agreement between 3D-SSFP, 83.3% agreement between CE-MRI, and 71.4% agreement between CE-CT and surgical findings regarding the level of IVC thrombus. In addition, 3D-SSFP showed a slightly superior estimate of pathological IVC volume. 3D-SSFP reached a significantly higher CNR in the supra- and infrarenal IVC compared to the morphological sequence T2-weighted half-Fourier axial single-shot fast spin-echo (T2-HASTE) and all phases of CE-MRI. More specifically, 3D-SSFP showed a significantly higher CNR in the infrarenal IVC (mean CNR of 10.09±5.74 versus 4.21±2.33 in the delayed phase, p≤0.001) and in the suprarenal IVC (mean CNR of 9.22±4.11 versus 4.84±5.74 in the late arterial phase, p=0.015). CE-CT also was significantly inferior to 3D-SSFP (p≤0.01) and slightly inferior to CE-MRI (p>0.05). The thrombus delineation score for 3D-SSFP (4.38±0.67) was higher compared to CE-MRI (3.76±0.56, p=0.005).

CONCLUSION

This preliminary study indicates that 3D-SSFP can achieve an accurate assessment of IVC thrombus in cRCC patients without the need for contrast medium administration, being superior to standard MRI and CT.

Pilot study of MRI/ultrasound fusion imaging in postpartum assessment of Cesarean section scar

OBJECTIVE

To evaluate prospectively the uterine scar after Cesarean section (CS) and the corresponding uterine region after vaginal delivery (VD) at 6 weeks postpartum using transabdominal (TAS) and transvaginal (TVS) sonography with magnetic resonance imaging (MRI) fusion to investigate whether fusion imaging allows standardized and reproducible identification of the scar location and measurement of uterine wall thickness compared with high-resolution MRI alone.

METHODS

Pelvic MRI was performed 6 weeks after delivery in 30 women (10 with planned CS (PCS), 10 with emergency CS (ECS) and 10 with VD). After transfer of MRI-DICOM datasets to the ultrasound system, the scar region after CS and the corresponding uterine region after VD were examined by TAS (5 MHz) and TVS (10 MHz) using smart fusion with MRI to guide visualization of the region in the corresponding sectional planes for both modalities. Vascularization of the scar region was determined as a percentage area using power Doppler ultrasound. Anterior (AW) and posterior (PW) uterine wall thickness was measured using TAS and TVS with fusion imaging and using MRI alone.

RESULTS

TVS with fusion imaging was applied successfully for uterine assessment at the end of the postpartum period in all women. TAS failed to identify the scar area in three women. Imaging techniques were similar in the evaluation of AW and PW thickness following VD. MRI and MRI/TVS fusion showed significant differences in AW thickness or scar area, in terms of the difference relative to PW thickness, in women with PCS and ECS (MRI: PCS, 4.3 mm; ECS, 4.2 mm; VD, 0.8 mm; P = 0.034; MRI/TVS fusion: PCS, 2.0 mm; ECS, 3.3 mm; VD, 0.0 mm; P = 0.01). The degree of vascularization in the scar region measured by power Doppler ultrasound was lower after PCS (13.1 ± 9.4%/area) and ECS (17.0 ± 8.2%/area) than after VD (34.6 ± 8.5%/area; P = 0.0017).

CONCLUSION

MRI/ultrasound fusion imaging can be performed in a reproducible manner for examination of the postpartum uterus. MRI/TVS fusion enables standardized identification of the CS scar location and vascularization is reduced in this area. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Evaluation of bone viability in patients after girdlestone arthroplasty: comparison of bone SPECT/CT and MRI

PURPOSE

To test the diagnostic performance of bone SPECT/CT and MRI for the evaluation of bone viability in patients after girdlestone-arthroplasty with histopathology used as gold standard.

MATERIALS AND METHODS

In this cross-sectional study, patients after girdlestone-arthroplasty were imaged with single-photon-emission-computed-tomography/computed-tomography (SPECT/CT) bone-scans using 99mTc-DPD. Additionally, 1.5 T MRI was performed with turbo-inversion-recovery-magnitude (TIRM), contrast-enhanced T1-fat sat (FS) and T1-mapping. All imaging was performed within 24 h prior to revision total-hip-arthroplasty in patients with a girdlestone-arthroplasty. In each patient, four standardized bone-tissue-biopsies (14 patients) were taken intraoperatively at the remaining acetabulum superior/inferior and trochanter major/minor. Histopathological evaluation of bone samples regarding bone viability was used as gold standard.

RESULTS

A total of 56 bone-segments were analysed and classified as vital (n = 39) or nonvital (n = 17) by histopathology. Mineral/late-phase SPECT/CT showed a high sensitivity (90%) and specificity (94%) to distinguish viable and nonviable bone tissue. TIRM (sensitivity 87%, specificity 88%) and contrast-enhanced T1-FS (sensitivity 90%, specificity 88%) also achieved a high sensitivity and specificity. T1-mapping achieved the lowest values (sensitivity 82%, specificity 82%). False positive results in SPECT/CT and MRI resulted from small bone fragments close to metal artefacts.

CONCLUSIONS

Both bone SPECT/CT and MRI allow a reliable differentiation between viable and nonviable bone tissue in patients after girdlestone arthroplasty. The findings of this study could also be relevant for the evaluation of bone viability in the context of avascular bone necrosis.

Longitudinal bone, muscle and adipose tissue changes in physically active subjects - sex differences during adolescence and maturity

OBJECTIVES

To explore changes in bone, muscle and adipose tissue composition in athletes with high physical activity levels at different stages of life.

METHODS

Thigh MRIs were acquired at baseline and 2-year follow-up for 20 young (16±1 years) and 20 mature (46±5 years) athletes (10 males, 10 females, respectively). Longitudinal changes in cross-sectional areas (CSAs) of femoral bone, quadriceps muscle, and thigh subcutaneous (SCF) and intermuscular (IMF) adipose tissue were evaluated.

RESULTS

Adolescent males displayed significant muscle (+5.0%, 95%CI: 0.8, 9.2) and bone growth (+2.9%, 95%CI: 1.3, 4.5), whereas adolescent females did not (muscle: +0.8%, 95%CI: -2.2, 3.8; bone: +1.9%, 95%CI: -2.1, 5.6). Adolescent and mature females showed significant SCF increases (+11.0%, 95%CI: 0.9, 21.1 and +6.0%, 95%CI: 0.6, 11.4, respectively), whereas adolescent and mature males did not (+7.2%, 95%CI: -8.0, 22.5 and +1.5%, 95%CI: -9.7, 11.8, respectively). Muscle and bone changes were highly correlated in adolescent males (r=0.66), mature males (r=0.75) and mature females (r=0.68) but not in adolescent females (r=-0.11).

CONCLUSIONS

The results suggest sex-specific patterns of age-related change in bone, muscle and adipose tissue, and tight coupling of bone and muscle growth. Sex-specific bone-muscle-adipose tissue relationships may have implications for understanding sex differences in fracture risk.

Significant muscle damage after multiple revision total hip replacements through the direct lateral approach

Intact abductors of the hip play a crucial role in preventing limping and are known to be damaged through the direct lateral approach. The extent of trauma to the abductors after revision total hip replacement (THR) is unknown. The aim of this prospective study was to compare the pre- and post-operative status of the gluteus medius muscle after revision THR. We prospectively compared changes in the muscle and limping in 30 patients who were awaiting aseptic revision THR and 15 patients undergoing primary THR. The direct lateral approach as described by Hardinge was used for all patients. MRI scans of the gluteus medius and functional analyses were recorded pre-operatively and six months post-operatively. The overall mean fatty degeneration of the gluteus medius increased from 35.8% (1.1 to 98.8) pre-operatively to 41% (1.5 to 99.8) after multiple revision THRs (p = 0.03). There was a similar pattern after primary THR, but with considerably less muscle damage (p = 0.001), indicating progressive muscle damage. Despite an increased incidence of a positive Trendelenburg sign following revision surgery (p = 0.03) there was no relationship between the cumulative fatty degeneration in the gluteus medius and a positive Trendelenburg sign (p = 0.26). The changes associated with other surgical approaches to the hip warrant investigation.

Molecular imaging in cardiovascular diseases

Cardiovascular diseases remain the leading cause of morbidity and mortality in industrialized and developing countries. In clinical practice, the in-vivo identification of atherosclerotic lesions, which can lead to complications such as heart attack or stroke, remains difficult. Imaging techniques provide the reference standard for the detection of clinically significant atherosclerotic changes in the coronary and carotid arteries. The assessment of the luminal narrowing is feasible, while the differentiation of stable and potentially unstable or vulnerable atherosclerotic plaques is currently not possible using non-invasive imaging. With high spatial resolution and high soft tissue contrast, magnetic resonance imaging (MRI) is a suitable method for the evaluation of the thin arterial wall. In clinical practice, native MRI of the vessel wall already allows the differentiation and characterization of components of atherosclerotic plaques in the carotid arteries and the aorta. Additional diagnostic information can be gained by the use of non-specific MRI contrast agents. With the development of targeted molecular probes, that highlight specific molecules or cells, pathological processes can be visualized at a molecular level with high spatial resolution. In this review article, the development of pathophysiological changes leading to the development of the arterial wall are introduced and discussed. Additionally, principles of contrast enhanced imaging with non-specific contrast agents and molecular probes will be discussed and latest developments in the field of molecular imaging of the vascular wall will be introduced.

Longitudinal analysis of MR spin-spin relaxation times (T2) in medial femorotibial cartilage of adolescent vs mature athletes: dependence of deep and superficial zone properties on sex and age

OBJECTIVE

Cartilage spin-spin magnetic resonance imaging (MRI) relaxation time (T2) represents a promising imaging biomarker of "early" osteoarthritis (OA) known to be associated with cartilage composition (collagen integrity, orientation, and hydration). However, no longitudinal imaging studies have been conducted to examine cartilage maturation in healthy subjects thus far. Therefore, we explore T2 change in the deep and superficial cartilage layers at the end of adolescence.

METHODS

Twenty adolescent and 20 mature volleyball athletes were studied (each 10 men and 10 women). Multi-echo spin-echo (MESE) images were acquired at baseline and 2-year follow-up. After segmentation, cartilage T2 was calculated in the deep and superficial cartilage layers of the medial tibial (MT) and the central, weight-bearing part of the medial femoral condyle (cMF), using five echoes (TE 19.4-58.2 ms).

RESULTS

16 adolescent (6 men, 10 women, baseline age 15.8 ± 0.5 years) and 17 mature (nine men, eight women, age 46.5 ± 5.2 years) athletes had complete baseline and follow-up images of sufficient quality to compute T2. In adolescents, a longitudinal decrease in T2 was observed in the deep layers of MT (-2.0 ms; 95% confidence interval (CI): [-3.4, -0.6] ms; P < 0.01) and cMF (-1.3 ms; [-2.4, -0.3] ms; P < 0.05), without obvious differences between males and females. No significant change was observed in the superficial layers, or in the deep or superficial layers of the mature athletes.

CONCLUSION

In this first pilot study on quantitative imaging of cartilage maturation in healthy, athletic subjects, we find evidence of cartilage compositional change in deep cartilage layers of the medial femorotibial compartment in adolescents, most likely related to organizational changes in the collagen matrix.

MRI of the breast as part of the assessment in population-based mammography screening

PURPOSE

To evaluate the indications and impact of MRI of the breast as an assessment modality in population-based mammography screening.

MATERIALS AND METHODS

135 consecutive contrast-enhanced MRI exams of the breast, which were performed between April 2007 and October 2012 as part of the assessment at one mammography screening unit before issuance of a final management recommendation (e. g. definitely benign or malignant), were retrospectively reviewed. Overall, the cases with an MRI exam of the breast during assessment represent less than 2 % of all assessment cases at this screening unit. All MRI exams were performed as part of the routine clinical care on a 1.5 T or 3 T whole-body magnet using a standard dynamic breast MRI protocol.

RESULTS

In the 135 study patients, a total of 30 malignancies in 28 patients were found, including two bilateral cancers. One patient was diagnosed with a non-Hodgkin lymphoma, and of the remaining 29 malignant lesions, 3 (10 %) were in-situ cancers (DCIS) and 26 (90 %) were invasive breast cancers including 3 multifocal or multicentric cancers. All 26 detected invasive cancers were lymph-node negative and 25/29 (86 %) of the detected breast cancer were early stage cancers (stage 0 or 1). 53 of the 135 MRI exams (39.3 %) were suspicious for malignancy (BIRADS 4 or 5) with no cancer missed by MRI. The sensitivity, specificity, positive predictive value, and negative predictive value of the MRI on a per patient basis were 100 %, 77 %, 0.53, and 1, respectively.

CONCLUSION

MRI is a useful problem-solving tool in mammography screening assessment with a high sensitivity and an acceptable positive predictive value.

Osteoporosis and atherosclerosis: a post-mortem MDCT study of an elderly cohort

OBJECTIVES

To evaluate how far fracture status and bone mineral density (BMD) correlate with the vascular calcification score (CS).

METHODS

On 29 complete human cadavers (17 female, 12 male; mean age at death was 85.57 years), multi-detector computed tomography was performed to assess the spine fracture status (fracture vs non-fracture [FX vs non-FX]) and CS of the coronary arteries (Coro-CS), the aorta (Aorta-CS) and the pelvic vessels (Iliac-CS). Quantitative computed tomography of the lumbar spine was performed to estimate overall BMD (osteoporotic [BMD <80 mg/cm(3)] vs non-osteoporotic [BMD ≥ 80 mg/cm(3)]).

RESULTS

Gender-specific differences in statistical significance were only observed for Aorta-CS and Iliac-CS but not for Coro-CS. When comparing the osteoporotic with the non-osteoporotic group, statistically significant differences were only found for Iliac-CS (P < 0.05); however, linear regression analysis showed none of the CSs to significantly correlate with BMD.

CONCLUSIONS

In our small post-mortem elderly population, statistically significant associations of fracture status and BMD with CS were only observed between the osteoporotic and non-osteoporotic groups for the pelvic vessels but not for the coronary arteries and the aorta.

KEY POINTS

• Gender-specific differences were observed for aortic and iliac calcification score (CS). • There was no difference in coronary CS between females and males. • Only iliac CS was different in osteoporotic and non-osteoporotic subjects. • In linear regression analysis, CS showed no correlation with BMD. • In univariate analysis, gender was a BMD and iliac CS confounder.

[MRI after patellar dislocation: assessment of risk factors and injury to the joint]

Patellar dislocation is the lateral displacement of the patella from the femoral trochlea. Affected individuals typically have underlying anatomic risk factors of variable magnitude, which, in conjunction with leg rotation, cause the event. Magnetic resonance imaging (MRI) permits straightforward diagnosis of the typical features of recent patellar dislocation: contusion edema of the inferomedial patella and the lateral femoral condyle as well as rupture of the medial patellofemoral ligament. In case of concomitant osteochondral injury, early surgical refixation may be indicated, depending on the size. After a first dislocation, which can damage the capsuloligamentous stabilizers, subjects may sustain further dislocations or even develop chronic patellofemoral instability, depending on the presence and severity of anatomic variants. A wide range of conservative and surgical treatments are available. While a first patellar dislocation is often treated conservatively, surgical strategies after a second dislocation depend on the pattern of injury and the severity of underlying anatomic risk factors. The most relevant predisposing variants are trochlear dysplasia, patella alta, and an abnormal tibial tubercle to trochlear groove distance (TT-TG). The radiologist's report should give a quantitative estimate of both the injuries resulting from dislocation and the underlying anatomic risk factors. An accurate characterization of the individual pathomechanism is crucial for tailoring treatment.

[Detection of prostate cancer by real-time MR/ultrasound fusion-guided biopsy: 3T MRI and state of the art sonography]

PURPOSE

Multiparametric MRI of the prostate is a noninvasive diagnostic method with high sensitivity and specificity for prostate cancer. The aim of this study is to evaluate whether prostate cancer detection rates of transrectal ultrasound (TRUS)-guided biopsy may be improved by an image fusion of state-of-the-art ultrasound (CEUS, elastography) and MR (T2w, DWI) imaging.

MATERIALS AND METHODS

32 consecutive patients with a history of elevated PSA levels and at least one negative TRUS-guided biopsy with clinical indication for a systematic re-biopsy underwent multiparametric 3 T MRI without endorectal coil. MR data (T2w) were uploaded to a modern sonography system and image fusion was performed in real-time mode during biopsy. B-mode, Doppler, elastography and CEUS imaging were applied to characterize suspicious lesions detected by MRI. Targeted biopsies were performed in MR/US fusion mode followed by a systematic standard TRUS-guided biopsy. Detection rates for both methods were calculated and compared using the Chi²-test.

RESULTS

Patient age was not significantly different in patients with and without histologically confirmed prostate cancer (65.2 ± 8.0 and 64.1 ± 7.3 age [p = 0.93]). The PSA value was significantly higher in patients with prostate cancer (15.5 ± 9.3 ng/ml) compared to patients without cancer (PSA 10.4 ± 9.6 ng/ml; p = 0.02). The proportion of histologically confirmed cancers in the study group (n = 32) of the MR/US fusion biopsy (11/12; 34.4 %) was significantly higher (p = 0.01) in comparison to the TRUS systematic biopsy (6/12; 18.8 %).

CONCLUSION

Real-time MR/US image fusion may enhance cancer detection rates of TRUS-guided biopsies and should therefore be studied in further larger studies.

The quality of bone surfaces may govern the use of model based fluoroscopy in the determination of joint laxity

The assessment of knee joint laxity is clinically important but its quantification remains elusive. Calibrated, low dosage fluoroscopy, combined with registered surfaces and controlled external loading may offer possible solutions for quantifying relative tibio-femoral motion without soft tissue artefact, even in native joints. The aim of this study was to determine the accuracy of registration using CT and MRI derived 3D bone models, as well as metallic implants, to 2D single-plane fluoroscopic datasets, to assess their suitability for examining knee joint laxity. Four cadaveric knees and one knee implant were positioned using a micromanipulator. After fluoroscopy, the accuracy of registering each surface to the 2D fluoroscopic images was determined by comparison against known translations from the micromanipulator measurements. Dynamic measurements were also performed to assess the relative tibio-femoral error. For CT and MRI derived 3D femur and tibia models during static testing, the in-plane error was 0.4 mm and 0.9 mm, and out-of-plane error 2.6 mm and 9.3 mm respectively. For metallic implants, the in-plane error was 0.2 mm and out-of-plane error 1.5 mm. The relative tibio-femoral error during dynamic measurements was 0.9 mm, 1.2 mm and 0.7 mm in-plane, and 3.9 mm, 10.4 mm and 2.5 mm out-of-plane for CT and MRI based models and metallic implants respectively. The rotational errors ranged from 0.5° to 1.9° for CT, 0.5-4.3° for MRI and 0.1-0.8° for metallic implants. The results of this study indicate that single-plane fluoroscopic analysis can provide accurate information in the investigation of knee joint laxity, but should be limited to static or quasi-static evaluations when assessing native bones, where possible. With this knowledge of registration accuracy, targeted approaches for the determination of tibio-femoral laxity could now determine objective in vivo measures for the identification of ligament reconstruction candidates as well as improve our understanding of the consequences of knee joint instability in TKA.

Diffuse idiopathic skeletal hyperostosis (DISH): relation to vertebral fractures and bone density

Radiographs and spinal bone mineral density (BMD) were evaluated from 342 elderly men regarding possible effects of diffuse idiopathic skeletal hyperostosis (DISH) on vertebral fractures and densitometry measurements. Prevalent vertebral fractures were more frequent among men with DISH compared to men with no DISH even after fracture prevalence was adjusted for BMD. Paravertebral calcifications should be considered in patients with DISH when interpreting BMD measurements because both dual X-ray absorptiometry (DXA) and quantitative CT (QCT) densitometry may not be reliable.

INTRODUCTION

The purpose of this study is to evaluate the prevalence of DISH in older men and its association with vertebral fractures and with BMD determined by DXA and QCT.

METHODS

Lateral radiographs of the spine were analyzed in a sample of 342 men aged ≥ 65 years participating in the MrOS Study concerning the presence and grade of DISH and vertebral fractures. Lumbar BMD was measured by both DXA (areal, grams per square centimeter) and QCT (volumetric, grams per cubic centimeter). The association between DISH, BMD, and presence of fractures was studied using χ ( 2 ) and t tests.

RESULTS

DISH was present in 52% (178/342) of the men. Men with DISH were older (mean, 75.1 vs 73.3, p < 0.05) and more likely to have prevalent fractures (28% vs 20%, p < p = 0.09). BMD assessed with DXA (1.08 vs 1.00 g/cm(2), p ≤ 0.0001), but not with QCT (0.11 vs 0.11 g/cm3, p = 0.65), was significantly higher in men with DISH compared to men without DISH. Significantly lower BMD of men with both DISH and fractures compared to men with DISH but without fractures was only detected by QCT (-25%, 0.09 vs 0.12, p < 0.05). Both DXA BMD and QCT BMD were significantly higher in severe lumbar DISH (+22% and +31%, p < 0.0001), respectively.

CONCLUSION

DISH was associated with a higher prevalence of vertebral fractures in elderly men. Lumbar ossifications related to DISH should be considered when interpreting BMD measurements to predict their fracture risk.

The influence of collagen network integrity on the accumulation of gadolinium-based MR contrast agents in articular cartilage

PURPOSE

Delayed gadolinium-enhanced MR imaging of cartilage is used to quantify the proteoglycan loss in early osteoarthritis. It is assumed that T1 after Gd-DTPA administration in the near equilibrium state reflects selective proteoglycan loss from cartilage. To investigate the influence of the collagen network integrity on contrast accumulation, the relaxation rates ΔR(1) and ΔR(2) were compared after Gd-DTPA administration in a well established model of osteoarthritis.

MATERIALS AND METHODS

Collagen or proteoglycan depletion was induced by the proteolytic enzymes papain and collagenase in healthy bovine patellar cartilage. Using a dedicated MRI sequence, T(1) and T(2) maps were simultaneously acquired before and 11 h after Gd-DTPA administration. Depth-dependent profiles of ΔR(1) and ΔR(2) were calculated in healthy, proteoglycan and collagen-depleted articular cartilage and the mean values of different cartilage layers were compared using the Mann-Whitney-U test.

RESULTS

In superficial layers (1 mm) there was no significant difference (p > 0.05) in either ΔR(1) or ΔR(2) between proteoglycan-depleted (16.6 ± 1.2 s(-1), 15.9 ± 1.0 s(-1)) and collagen-depleted articular cartilage (15.3 ± 0.9 s(-1), 15.5 ± 0.9 s(-1)). In deep layers (3 mm) both parameters were significantly higher (p = 0.005, 0.03) in proteoglycan-depleted articular cartilage (12.3 ± 1.1 s(-1), 9.8 ± 0.8 s(-1)) than in collagen-depleted articular cartilage (9.1 ± 1.1 s(-1), 8.7 ± 0.7 s(-1)).

CONCLUSION

Both proteoglycan loss and alterations in the collagen network influence the accumulation of Gd-DTPA in articular cartilage with significant differences between superficial and deep cartilage layers.

Intravenöse Kontrastmittel oral appliziert: Eine wohlschmeckende Alternative zum herkömmlichen oralen Kontrastmittel in der Computertomografie

PURPOSE

Many patients dislike oral contrast media due to their bad taste. The aim of the present study was to identify a solution that tastes better while providing the same opacification in order to offer oncological patients an alternative to the routinely used bad tasting oral contrast media.

MATERIALS AND METHODS

In a single blinded, prospective clinical study, the orally administered intravenous contrast media iohexol (Omnipaque), iopromide (Ultravist), and iotrolan (Isovist) as well as the oral contrast media sodium amidotrizoate (Gastrografin) and ioxithalamate (Telebrix) were each compared to the oral contrast medium lysine amidotrizoate as the reference standard at a constant dilution. The density values of all contrast media with the same dilutions were first measured in a phantom study. The patient study included 160 patients who had undergone a prior abdominal CT scan with lysine amidotrizoate within 6 months. The patients rated their subjective taste impression on a scale of 0 (very bad) to 10 (excellent). In addition, adverse events and opacification were recorded and prices were compared.

RESULTS

The phantom study revealed identical density values. Patients assigned much higher taste impression scores of 8 and 7 to iohexol and iotrolan, respectively, as compared to a score of 3 for the conventional lysine amidotrizoate (p< 0.05). Iopromide and sodium amidotrizoate did not differ significantly from lysine amidotrizoate. The opacification of all contrast media and experienced adverse events did not differ significantly. Iotrolan (ca. 120 euro/100 ml), Iohexol and Iopromide (ca. 70 euro/100 ml) are more expensive than the conventional oral contrast media (ca. 10 - 20 euro/100 ml).

CONCLUSION

Orally administered solutions of non-ionic contrast media improve patient comfort due to the better taste and provide the same opacification in comparison to conventional oral contrast media. At present, their use should be limited to individual cases due to the higher costs.

Cine magnetic resonance imaging of the small bowel: comparison of different oral contrast media

PURPOSE

To evaluate several substances regarding small bowel distension and contrast on balanced steady-state free precession (bSSFP) cine magnetic resonance (MR) images.

MATERIAL AND METHODS

Luminal contrast was evaluated in 24 volunteers after oral application of two different contrast agent groups leading to either bright lumen (pineapple, blueberry juice) or dark lumen (tap water, orange juice) on T1-weighted images. Bowel distension was evaluated in 30 patients ingesting either methylcellulose or mannitol solution for limiting intestinal absorption. Fifteen patients with duodeno-jejunal intubation served as the control. Quantitative evaluation included measurement of luminal signal intensities and diameters of four bowel segments, qualitative evaluation assessed luminal contrast and distension on a five-point scale.

RESULTS

Quantitative and qualitative evaluation of the four contrast agents revealed no significant differences regarding luminal contrast on bSSFP images. Quantitative evaluation revealed significantly lower (P<0.05) small bowel distension for three out of four segments (qualitative evaluation: two out of four segments) for methylcellulose in comparison to the control. Mannitol was found to be equal to the control.

CONCLUSION

Oral ingestion of tap water or orange juice in combination with mannitol is recommended for cine MR imaging of the small bowel regarding luminal contrast and small bowel distension on bSSFP sequences.