Arterioportal shunts mimicking hepatic tumors with hyperintensity on T2-weighted MR images

We report and assess the imaging findings in a patient with multiple arterioportal shunting mimicking multiple hypervascular tumors that showed multiple areas of hyperintensity with gadolinium-enhanced gradient-recalled-echo images obtained in the hepatic arterial phase and corresponding areas of slight hyperintensity with T2-weighted images.     

Pre- and postprandial alterations of portal venous flow: evaluation with single breath-hold three-dimensional half-Fourier fast spin-echo MR imaging and a selective inversion recovery tagging pulse

PURPOSE: To evaluate the influence of food intake on portal flow using unenhanced magnetic resonance imaging (MRI). MATERIALS AND METHODS: The study population included 29 healthy subjects. A selective inversion recovery tagging pulse was used on the superior mesenteric vein (SMV) and splenic vein (SpV) to study the correlation of tagged blood in the portal vein (PV). MRI was performed before and 60-90 min after a meal. RESULTS: The flow signal from the SMV increased in 97% of the subjects after the meal. Before the meal the portal flow was dominated by flow from the SpV in 59% of the subjects, while it was dominated by flow from the SMV in 76% of the subjects after the meal. The most common distribution pattern of the flow signal from the SpV before the meal was in the central part of the main PV (55%), while it was in the left side (45%) after the meal. The most common distribution pattern of the flow signal from the SMV was in the bilateral sides of the main PV both before and after the meal (62%). CONCLUSION: This technique shows potential for evaluating pre- and postprandial alterations of flow from the SpV and SMV in the PV under physiological conditions.     

Fat-suppressed T2-weighted MRI of the liver: comparison of respiratory-triggered fast spin-echo, breath-hold single-shot fast spin-echo, and breath-hold fast-recovery fast spin-echo sequences

The purpose of our study was to compare the value of respiratory-triggered fast spin-echo, breath-hold single-shot fast spin-echo, and breath-hold fast-recovery fast spin-echo sequences in detecting hepatic lesions. Fat-suppressed T2-weighted magnetic resonance (MR) images obtained with the three sequences in 36 patients with 138 lesions and nine patients without lesions were prospectively analyzed. Quantitative and qualitative analyses, including receiver operating characteristic (ROC) analyses, were performed. The mean lesion-to-liver contrast-to-noise ratio (CNR) for hepatic lesions was highest with the respiratory-triggered fast spin-echo sequence. On the basis of receiver-operating characteristic analyses, tumor detection rates were higher with the breath-hold fast-recovery fast spin-echo sequence (Az = 0.94) than with the respiratory-triggered fast spin-echo sequence (AZ = 0.80, P < 0.0001) or the single-shot fast spin-echo sequence (Az = 0.77, P < 0.0001). The image quality with the breath-hold fast-recovery fast spin-echo sequence was acceptable in all patients. The breath-hold fast-recovery fast spin-echo sequence provided the highest tumor detection in a short imaging time, although the mean lesion-to-liver CNRs were inferior to those of the respiratory-triggered fast spin-echo and the breath-hold single-shot fast spin-echo sequences.     

Gadolinium-enhanced T1-weighted renal and abdominal MR imaging: quantitative discrepancy between clinical and in vitro findings

RATIONALE AND OBJECTIVES: This study was conducted to compare the magnetic resonance (MR) contrast medium enhancement of abdominal organs in vivo with the signal intensity (SI) values of known in vitro gadolinium solutions. MATERIALS AND METHODS: A phantom was imaged with the MR contrast medium gadodiamide (Omniscan; Nycomed, Princeton, NJ) of solutions at full-strength (0.5 mmol/mL), one-third, 1/10, and 1/100 concentrations. A fat-suppressed fast spoiled gradient-echo pulse sequence with flip angles ranging from 10 degrees to 170 degrees (at 20 degrees increments) was performed with a 1.5-T magnet. In 12 subjects, the SIs of abdominal organs were determined with identical imaging parameters, before and after administration of gadodiamide injection at 0.1 mmol/kg. RESULTS: As anticipated, the plot of SI in relation to gadodiamide concentration is nonlinear, with a decrease in SI due to T2 effects at concentrations above 0.05 mmol/mL. The kidney showed the highest SI after gadodiamide enhancement (125.2 +/- 11.6 [standard error] at 2.5 minutes), followed by the liver (76.5 +/- 11.5 at 1 minute) and spleen (57.26 +/- 9.35 at 30 seconds). The SI of the renal medulla (114.2 +/- 9.8 at 4.5 minutes) was approximately one-third that in phantom observations. CONCLUSION: The authors observed a marked discrepancy between empirical contrast medium performance in abdominal organs and SI values for comparable gadodiamide concentrations in vitro. One possible reason is the intracellular compartmentalization of water molecules in vivo. These results suggest a need for a better understanding of MR contrast medium performance in vivo.     

Assessment of portal venous system patency in the liver transplant candidate: a prospective study comparing ultrasound,microbubble-enhanced colour Doppler ultrasound,with arteriography and surgery

AIM: To determine the role of microbubble-enhanced colour Doppler ultrasound (CDUS) in assessing portal venous patency prior to liver transplantation. MATERIALS AND METHODS: Over a 2-year period, all patients with chronic liver disease undergoing routine pre-transplant CDUS examination in whom the portal venous system was inadequately demonstrated were recruited to the study. CDUS was performed in 368 patients and 33 patients (9%) were recruited. A repeat CDUS examination following an intravenous bolus injection of the microbubble contrast agent Levovist (Schering Healthcare AG, Berlin, Germany) was performed. Diagnostic confidence was recorded on a free linear analogue scale for both examinations. Findings were compared with indirect portography and surgery. RESULTS: Of the 33 patients with sub-optimal baseline examinations, improvement in portal vein visualization was achieved in 31 patients (94%). Median diagnostic confidence increased from 50% (interquartile range 30-60) to 90% (interquartile range 75-98) (P < 0.001) following administration of Levovist. Overall accuracy of portal vein assessment using microbubble-enhanced CDUS in 15 patients in whom a definitive diagnosis was made within 2 months was 87%. CONCLUSION: Microbubble-enhanced CDUS is a simple, inexpensive adjunct to standard pre liver transplant screening of the portal vein. It is particularly helpful in patients with end-stage cirrhosis who are at high risk of portal vein thrombosis and in whom the conventional examination is sub-optimal.     

Unsuppressed fat in the right anterior diaphragmatic region on fat-suppressed T2-weighted fast spin-echo MR images

The authors retrospectively evaluated magnetic resonance Images of the abdomen obtained In 52 consecutive patients. All cases included fast spinecho (FSE) T2-weighted images acquired with a frequency-selective fat saturation technique. All imaging was performed with a 1.5-T unit. In 42 patients (81%), fat was not suppressed in the right anterior diaphragmatic region on the T2-welghted FSE images with fat suppression. In 11 (26%) of these 42 patients, subcutaneous fat adjacent to the unsuppressed anterior diaphragmatic fat was well suppressed. Hence, the fat In the diaphragmatic region mimicked fluid or peritoneal implants. The cause of the artifact appears to be the juxtaposition of liver, fat, and lung parenchymal air within a small anatomic space, creating a localized inhomogeneity of the magnetic field and susceptibility effects. Radiologists should be aware of this phenomenon to prevent confusion of an artifact with fluid or neoplasms.     

Detection of hepatocellular carcinoma by ferumoxides-enhanced MR imaging in cirrhosis: Incremental value of dynamic gadolinium-enhancement

PURPOSE: To investigate the incremental value of dynamic gadolinium-enhancement performed immediately after ferumoxides-enhanced magnetic resonance (MR) imaging on the detection of hepatocellular carcinoma in patients with cirrhosis. MATERIALS AND METHODS: We retrospectively reviewed MR scans of 62 cirrhotic patients over a two-year period. Sequences included ferumoxides-enhanced T2-weighted fast spin echo followed by dynamic gadolinium-enhanced T1-weighted spoiled gradient echo. Two readers independently documented the presence of hepatocellular carcinoma on a three-point confidence scale, without and with gadolinium-enhanced images. The presence or absence of hepatocellular carcinoma was established by histopathology (58 patients) or follow-up imaging (four patients) over a mean period of nine months. RESULTS: A total of 71 hepatocellular carcinomas were found in 42 patients. There was no statistically significant difference in sensitivity for the diagnosis of hepatocellular carcinoma without vs. with gadolinium-enhanced images (68% vs. 74% for reader 1 and 62% vs. 73% for reader 2, respectively, P > 1.3). However, both readers showed a lower mean confidence for tumor detection without vs. with gadolinium-enhanced images (2.3 vs. 2.7 for reader 1, 2.3 vs. 2.9 for reader 2, P < 0.01). CONCLUSION: In our study, the addition of dynamic gadolinium-enhancement to ferumoxides-enhanced MR imaging did not improve hepatocellular carcinoma detection, but the addition of gadolinium-enhancement is recommended if ferumoxides-enhanced imaging is used because it increased reader confidence.     

Correlation of single-lumen silicone implant integrity with chemical shift artifact on T2-weighted magnetic resonance images

PURPOSE: To correlate the integrity of single-lumen silicone gel implants with chemical shift artifact (CSA) associated with infolding of the elastomer shell. MATERIALS and METHODS: The T2-weighted images of presurgical MRI examinations of 54 implants were retrospectively reviewed by two breast radiologists blinded to the operative and pathologic findings. CSA associated with intraluminal membranes was quantified by determining the fraction of membranes with it and categorized as minimal (0-1/3 of membranes involved), moderate (>1/3- <2/3), and marked (2/3 to all). CSA was qualified by noting whether CSA intensity of the membranes was less than or similar to that of blood vessels. The CSA was correlated with the surgical or pathology findings to judge integrity of the implant. RESULTS: Nineteen implants were intact, 35 were dysfunctional (gel leakage or rupture). Twenty-eight of 29 (97%) with a minimal fraction of membranes with CSA were dysfunctional; 17/21 (81%) with CSA associated with a marked fraction of membranes were intact (P < 0.001). All 28 implants with CSA intensity less than vessels were dysfunctional, 19/26 (73%) with CSA equal to vessels were intact (P < 0.001). All 25 implants with minimal CSA and intensity less than vessels were dysfunctional. Seventeen of 19 (89%) implants with CSA associated with a marked fraction of membranes and intensity equal to vessels were intact (P = 0.02). The magnetic resonance imaging (MRI) signs were combined with strong CSA as a predictor of integrity, and 22 of 26 (85%) implants were correctly diagnosed, 4 dysfunctional and 18 intact (P < 0.0001). CONCLUSION: CSA correlates with integrity of silicone gel implants on T2-weighted images and can be used with other MRI signs to improve diagnosis.     

Multinodular focal fatty infiltration of the liver: atypical imaging findings on delayed T1-weighted Gd-BOPTA-enhanced liver-specific MR images

We report a case of pathologically confirmed multinodular focal fatty infiltration. MRI was performed after bolus injection of gadobenate dimeglumine (Gd-BOPTA, MultiHance; Bracco, Milan, Italy), a liver-specific paramagnetic, gadolinium (Gd)-based MR contrast agent that concomitantly enables the acquisition of a standard dynamic phase with timing strategies similar to those used for other extracellular fluid contrast agents, followed by a delayed T1-weighted liver-specific phase (the so-called hepatobiliary phase). In the present case, multiple rounded areas of fatty infiltration, although confidently diagnosed using chemical shift sequences due to a significant signal intensity reduction on out-of-phase images, were unexpectedly hypointense during the delayed liver-specific phase of Gd-BOPTA. Reduced Gd-BOPTA concentration during the liver-specific phase is generally correlated with liver malignancy. Since such lesions can be prospectively mistaken for metastatic disease, we performed a hepatic biopsy to establish a definitive diagnosis. Our empirical observations suggest that Gd-BOPTA uptake may be impaired in fatty infiltrated liver tissue. Because at present there is no report evaluating the kinetics of Gd-BOPTA in fatty liver, further studies are needed to specifically investigate this issue.     

Streamlined flow in the portal vein: demonstration with MR angiography

PURPOSE: To demonstrate whether streamlining of the portal vein flow exists by evaluating the relative distribution of blood flowing from the superior mesenteric vein (SMV) and splenic vein (SV) into the portal venous system. MATERIALS AND METHODS: Fifteen healthy adult volunteers underwent MR angiography of the main portal vein (PV) and portal vein branches after an overnight fast. Transverse two dimension time-of-flight gradient echo sequences were obtained three times, in suspended expiration and inspiration, respectively, as follows: 1) No presaturation slab, 2) presaturation slab across the SMV, 3) presaturation slab across the SV. Signal intensity (SI) measurements were obtained for all acquisitions. using regions of interest traced manually within the PV and portal branches. RESULTS: After presaturation of the SMV and SV during expiration, the overall SI average in the PV decreased by 47% +/- 8 (mean +/- SD) and 17% +/- 9, respectively. Right to left portal branch SI ratio and right-anterior to left-posterior SI ratio in the PV were 0.91 +/- 0.09 and 1.02 +/- 0.08 at baseline, respectively. They decreased significantly (P < 0.05) to 0.87 +/- 0.09 and to 0.95 +/- 0.09 after saturation of the SMV, and increased significantly to 0.95 +/- 0.08 and to 1.07 +/- 0.10 after saturation of the SV. CONCLUSION: MR angiography with selective saturation of the SMV and SV provided reproducible assessment of the respective contributions of the SMV and SV to portal flow, and allows demonstration that streamlining of splanchnic blood occurs in the portal vein of normal subjects.     

Small scirrhous hepatocellular carcinoma with central scar: MR imaging findings

We describe the magnetic resonance (MR) imaging findings of a small scirrhous hepatocellular carcinoma in a 74-year-old man. The initial MR imaging findings indicated that the tumor had a small central scar, which suggested the differential diagnoses of hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and metastasis. A small scirrhous hepatocellular carcinoma may have a central scar and should be included in the differential diagnoses for small hepatic masses with a central scar.     

Characterization of focal hepatic lesions with ferumoxides-enhanced MR imaging: utility of T1-weighted spoiled gradient recalled echo images using different echo times

PURPOSE: To evaluate the different signal characteristics of focal hepatic lesions on ferumoxides-enhanced MR imaging, including T1-weighted spoiled gradient recalled echo (GRE) images using different echo times (TE) and T2- and T2*-weighted images. MATERIALS AND METHODS: Ferumoxides-enhanced MR imaging was performed using a 1.5-T system in 46 patients who were referred for evaluation of known or suspected hepatic malignancies. One hundred and seven lesions (42 hepatocellular carcinomas [HCC], 40 metastases, 13 cysts, eight hemangiomas, three focal nodular hyperplasias [FNHs], and one cholangiocarcinoma) were evaluated. Postcontrast MR imaging included 1) T2-weighted FSE; 2) T2*-weighted GRE; 3) T1-weighted spoiled GRE using moderate (TE = 4.2-4.4 msec) TE; and 4) minimum (TE = 1.8-2.1 msec) TE. Signal intensities of the focal lesions were rated by two radiologists in conference as follows: hypointense, isointense or invisible, hyperintense, and markedly hyperintense. Lesion-to-liver contrast-to-noise ratio (C/N) was measured by one radiologist for a quantitative assessment. RESULTS: On ferumoxides-enhanced FSE images, 92% of cysts were "markedly hyperintense" and most of the other lesions were "hyperintense", and the mean C/N of cysts was significantly higher than that of other focal lesions. T2*-weighted GRE images showed most lesions with similar hyperintensities and the mean C/N was not significantly different between any two types of lesion. T1-weighted GRE images using moderate TE showed all FNHsand hemangiomas, 29 (69%) HCCs and eight (20%) metastases as "hyperintense". On T1-weighted GRE images using minimum TE, however, all HCCs and metastasis except one were iso- or hypointense, while all of the FNHs and hemangiomas were hyperintense. Ring enhancement was highly suggestive of malignant lesions, and was more commonly seen on the minimum TE images than on the moderate TE images. CONCLUSION: Addition of T1-weighted GRE images using minimum and moderate TE is helpful for characterizing focal lesions in ferumoxides-enhanced MR imaging.     

Hemodynamic characterization of focal hepatic lesions: role of ferucarbotran-enhanced dynamic MR imaging using T2-weighted multishot spin-echo echo-planar sequence

PURPOSE: To investigate the role of ferucarbotran-enhanced dynamic MR imaging using multishot spin-echo echo-planar sequence in the evaluation of hemodynamics of focal hepatic lesions. MATERIALS AND METHODS: Sixty-three focal hepatic lesions (24 benign and 39 malignant) from 53 consecutive patients who underwent both ferucarbotran-enhanced MR imaging and dynamic computed tomography (CT) were included in this study. MR imaging was performed with a 1.5-T scanner with a phased-array coil. T2-weighted multishot spin-echo echo-planar sequences (TR/TE = 1714-2813/80 msec) were obtained during a single breathhold before and 15, 60, 120, 180, and 600 seconds after intravenous injection of ferucarbotran. The enhancement patterns of lesions were classified into three categories by a study coordinator on the basis of dynamic CT images as hypervascular, hypovascular, and hemangioma type. The study coordinator created mean contrast-to-noise ratio of lesions vs. time curves for each enhancement pattern for quantitative analyses. Moreover, three radiologists separately and blindly reviewed MR images, and then assigned three confidence scores for the three enhancement patterns to each lesion. Sensitivity, specificity, and receiver operating characteristic analyses were performed. RESULTS: Quantitative analyses showed characteristic enhancement curves for each enhancement pattern. Mean sensitivities/specificities were 0.816/0.882, 0.897/0.863, and 0.800/0.989 for hypervascular, hypovascular, and hemangioma types, respectively. Mean areas under the receiver operating characteristic curve were 0.886 for hypervascular type and 0.913 for hypovascular type. CONCLUSION: Ferucarbotran-enhanced dynamic MR imaging can be used to successfully characterize the hemodynamics of focal hepatic lesions.     

Differentiation between cavernous hemangiomas and untreated malignant neoplasms of the liver with free-breathing diffusion-weighted MR imaging: Comparison with T2-weighted fast spin-echo MR imaging

Objective

To test interobserver variability of ADC measurements and compare the diagnostic performances of free-breathing diffusion-weighted (FBDW) with that of T2-weighted FSE (T2WFSE) MR imaging for differentiating between cavernous hemangiomas and untreated malignant hepatic neoplasms.

Materials and methods

Thirty-five patients with cavernous hemangiomas and 35 with untreated hepatic malignant neoplasms had FBDW and T2WFSE MR imaging. Hepatic lesions were characterized with ADC measurement and visual evaluation. Interobserver agreement for ADC measurement was calculated. Association between ADC value and lesion type was assessed using univariate analysis. Sensitivity, specificity and accuracy of ADC values and visual evaluation of MR images for the diagnosis of untreated malignant hepatic neoplasm were compared.

Results

ADC measurements showed excellent interobserver correlation (intraclass correlation coefficient = 0.980). Malignant neoplasms had lower ADC values than hemangiomas for the two observers (1.11 × 10⁻³ mm²/s ± .21 × 10⁻³vs. 1.77 × 10⁻³ mm²/s ± .29 × 10⁻³ for observer 1 and 1.11 × 10⁻³ mm²/s ± .19 × 10⁻³vs. 1.79 × 10⁻³ mm²/s ± .32 × 10⁻³ for observer 2) and univariate analysis found significant correlations between lesion type and ADC values. Depending on ADC threshold value, accuracy for the diagnosis of malignant neoplasm varied from 82.9% to 94.3%. Using visual evaluation, FBDW showed better specificity and accuracy than T2WFSE MR images for the diagnosis of malignant neoplasm (97.1% vs. 77.1% and 94.3% vs. 62.9%, respectively).

Conclusion

FBDW imaging provides reproducible quantitative information and surpasses the value of T2WFSE MR imaging for differentiating between cavernous hemangiomas and untreated malignant hepatic neoplasms.     

MR angiography of the carotid arteries: parameters affecting image quality

RATIONALE AND OBJECTIVES: This study was performed to evaluate the relationship between dose levels of contrast medium and image quality in magnetic resonance (MR) angiography of the carotid arteries with fluoroscopically monitored, manually triggered, elliptically ordered image acquisitions. MATERIALS AND METHODS: Twenty-five patients with clinical indications for angiography of the carotid arteries were examined with MR at 1.5 T by using a fluoroscopically monitored, manually triggered, elliptically ordered pulse sequence with the administration of one of three different volumes of gadolinium-based contrast medium. The signal intensities of the vessel lumen and the surrounding tissues were measured in single partitions at the origin of the common carotid artery, the carotid bifurcation, and the intracranial internal carotid arteries. The contrast-to-noise ratio in these regions of interest also was measured. Maximum intensity projection image quality was appraised for blurring, artifacts, venous enhancement, background suppression, and contrast medium distribution. RESULTS: No artifacts or venous enhancement was observed. The position of the fluoroscopic section affected the distribution of contrast medium along the vessel, as evidenced by the difference between the contrast-to-noise ratio at the origin of the common carotid artery and the ratio at the carotid bifurcation and the intracranial internal carotid arteries (P < .01). The contrast medium dose administered was strongly correlated with image quality (r = 0.90). CONCLUSION: Contrast medium dose is related to image quality in MR angiography of the carotid arteries performed with elliptical ordering, fluoroscopic monitoring, and manual triggering.     

T1-Weighted MR imaging of the brain using a fast inversion recovery pulse sequence

The purpose of this paper was to develop and evaluate a fast inversion recovery (FIR) technique for T1-weighted MR imaging of contrast-enhancing brain pathology. The FIR technique was developed, capable of imaging 24 sections in approximately 7 minutes using two echoes per repetition and an alternating echo phase encoding assignment. Resulting images were compared with conventional T1-weighted spin echo (T1SE) images in 18 consecutive patients. Compared with corresponding T1SE images, FIR images were quantitatively comparable or superior for lesion-to-background contrast and contrast-to-noise ratio (CNR). Gray-to-white matter and cerebrospinal fluid (CSF)-to-white matter contrast and CNR were statistically superior in FIR images. Qualitatively, the FIR technique provided comparable lesion detection, improved lesion conspicuity, and superior image contrast compared with T1SE images. Although FIR images had greater amounts of image artifacts, there was not a statistically increased amount of interpretation-interfering image artifact. FIR provides T1-weighted images that are superior to T1SE images for a number of image quality criteria.     

Comparison of T2-weighted spin-echo and fast spin-echo techniques in the evaluation of myelination

To evaluate T2-weighted fast spin-echo (FSE) and conventional spin-echo (CSE) magnetic resonance (MR) techniques in the assessment of brain myelination, 100 consecutive pediatric patients were imaged prospectively with both CSE and FSE sequences. All patients underwent a routine MR examination that included T2-weighted CSE imaging (imaging time, 10 minutes 21 seconds) and T2-weighted FSE imaging (imaging time, 2 minutes 5 seconds). The two techniques were compared for estimating the degree of myelination (using normal anatomic landmarks) by blind review. With T2-weighted CSE images as the “gold standard” for estimation of normal myelination, FSE images were evaluated to determine if they showed the degree of myelination similarly to CSE images. There was a strong correlation (P <.01) between CSE and FSE images in the estimation of myelination over a wide range of patient ages.     

MR imaging of the liver: Effect of portal hypertension on hepatic parenchymal enhancement using a gadolinium chelate

The purpose of this study was to prospectively investigate the extent to which reduced portal blood flow in patients with hepatic cirrhosis and portal hypertension affects hepatic parenchymal enhancement during gadolinium-chelate-enhanced dynamic MR imaging. Breath-hold three-dimensional (3D) spoiled gradientrecalled echo (GRE) MR imaging technique obtained after intravenous administration of a gadolinium chelate was used to measure hepatic parenchymal enhancement and time to peak enhancement in 20 patients with hepatic cirrhosis and clinical evidence of portal hypertension (group 1) and in 20 control subjects without portal hypertension (group 2) who were matched for age, sex, and body weight. Mean peak hepatic enhancement values ± SD and times to peak enhancement ± SD were determined for both groups of patients. Mean peak enhancement value (±SD) was 78.7% ± 36.2 in group 1 and 91.6% ± 46.2 in group 2 (not significant). However, in the nine patients in group 1 with splenomegaly, mean peak enhancement value was 61.3% ± 14.4, whereas it was 93.0% ± 42.7 in the 11 patients without splenomegaly (P < .05). Mean time to peak enhancement was 84 seconds ± 23 in group 1 and 54.0 sec ± 25.0 in group 2 (P < .01). Our results show that mean peak enhancement value of hepatic parenchyma after intravenous administration of a gadolinium chelate is significantly altered for patients with portal hypertension and splenomegaly. In addition, the time to peak enhancement is delayed significantly when portal hypertension is present. Thus, it is possible that the optimal time for imaging the liver during the portal phase must be tailored to the status of the portal system of the patient.     

Gadoxetic acid-enhanced T1-weighted MR cholangiography in primary sclerosing cholangitis

Purpose:

To investigate the value of gadoxetic acid‐enhanced three‐dimensional T1‐weighted MR cholangiography (T1w‐MRC) in comparison to three‐dimensional T2‐weighted MR cholangiopancreaticography (T2w‐MRCP) in patients with primary sclerosing cholangitis (PSC).

Materials and Methods:

Thirty‐four MR exams in 29 patients (46.0 ± 16.1 years; 19 men, 10 women) scanned within a 14‐month period were retrospectively included. Two abdominal radiologists independently evaluated image quality regarding image contrast, image quality degradation due to artifacts, and visualization quality of ducts. The order of biliary tree branches that were visualized and reader preference toward each method were recorded. Helpfulness of T1w‐MRC was scored in consensus. Confirmatory endoscopic retrograde cholangiopancreaticography (ERCP) performed within 3 months of the MR examination was available in 8 patients.

Results:

Image quality of T1w‐MRC and T2w‐MRCP was graded good to excellent in all cases. There were advantages for both T1w‐MRC (functional information, less degradation due to artifacts) and T2w‐MRCP (higher order of visualized branches, better branch depiction). Both readers showed preference for T2w‐MRCP; however, both readers found gadoxetic acid–enhanced T1w‐MRC helpful in the majority of cases.

Conclusion:

Gadoxetic acid‐enhanced T1w‐MRC is complementary to, but should not replace, T2w‐MRCP. T1w‐MRC is a useful adjunct to T2w‐MRCP for morphologic evaluation and provides additional diagnostic information. J. Magn. Reson. Imaging 2012;36:632–640. © 2012 Wiley Periodicals, Inc.     

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