The Performance of Flash Replenishment Contrast-Enhanced Ultrasound for the Qualitative Assessment of Kidney Lesions in Patients with Chronic Kidney Disease

We investigated the accuracy of CEUS for characterizing cystic and solid kidney lesions in patients with chronic kidney disease (CKD). Cystic lesions are assessed using Bosniak criteria for computed tomography (CT) and magnetic resonance imaging (MRI); however, in patients with moderate to severe kidney disease, CT and MRI contrast agents may be contraindicated. Contrast-enhanced ultrasound (CEUS) is a safe alternative for characterizing these lesions, but data on its performance among CKD patients are limited. We performed flash replenishment CEUS in 60 CKD patients (73 lesions). Final analysis included 53 patients (63 lesions). Four readers, blinded to true diagnosis, interpreted each lesion. Reader evaluations were compared to true lesion classifications. Performance metrics were calculated to assess malignant and benign diagnoses. Reader agreement was evaluated using Bowker's symmetry test. Combined reader sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing malignant lesions were 71%, 75%, 45%, and 90%, respectively. Sensitivity (81%) and specificity (83%) were highest in CKD IV/V patients when grouped by CKD stage. Combined reader sensitivity, specificity, PPV, and NPV for diagnosing benign lesions were 70%, 86%, 91%, and 61%, respectively. Again, in CKD IV/V patients, sensitivity (81%), specificity (95%), and PPV (98%) were highest. Inter-reader diagnostic agreement varied from 72% to 90%. In CKD patients, CEUS is a potential low-risk option for screening kidney lesions. CEUS may be particularly beneficial for CKD IV/V patients, where kidney preservation techniques are highly relevant.

Thermal ablation compared to stereotactic body radiation therapy for hepatocellular carcinoma: A multicenter retrospective comparative study

BACKGROUND AIMS

Early-stage HCC can be treated with thermal ablation or stereotactic body radiation therapy (SBRT). We retrospectively compared local progression, mortality, and toxicity among patients with HCC treated with ablation or SBRT in a multicenter, US cohort.

APPROACH RESULTS

We included adult patients with treatment-naïve HCC lesions without vascular invasion treated with thermal ablation or SBRT per individual physician or institutional preference from January 2012 to December 2018. Outcomes included local progression after a 3-month landmark period assessed at the lesion level and overall survival at the patient level. Inverse probability of treatment weighting was used to account for imbalances in treatment groups. The Cox proportional hazard modeling was used to compare progression and overall survival, and logistic regression was used for toxicity. There were 642 patients with 786 lesions (median size: 2.1 cm) treated with ablation or SBRT. In adjusted analyses, SBRT was associated with a reduced risk of local progression compared to ablation (aHR 0.30, 95% CI: 0.15-0.60). However, SBRT-treated patients had an increased risk of liver dysfunction at 3 months (absolute difference 5.5%, aOR 2.31, 95% CI: 1.13-4.73) and death (aHR 2.04, 95% CI: 1.44-2.88, p < 0.0001).

CONCLUSIONS

In this multicenter study of patients with HCC, SBRT was associated with a lower risk of local progression compared to thermal ablation but higher all-cause mortality. Survival differences may be attributable to residual confounding, patient selection, or downstream treatments. These retrospective real-world data help guide treatment decisions while demonstrating the need for a prospective clinical trial.

Current Opinion on the Use of Magnetic Resonance Imaging in Staging Prostate Cancer: A Narrative Review

Accurate staging is critical for treatment planning and prognosis in men with prostate Cancer. Prostate magnetic imaging resonance (MRI) may aid in the staging evaluation by verifying organ-confined status, assessing the status of the pelvic lymph nodes, and establishing the local extent of the tumor in patients being considered for therapy. MRI has a high specificity for diagnosing extracapsular extension, and therefore may impact the decision to perform nerve sparing prostatectomy, along with seminal vesicle invasion and lymph node metastases; however, its sensitivity remains limited. Current guidelines vary significantly regarding endorsing the use of MRI for staging locoregional disease. For high-risk prostate cancer, most guidelines recommend cross sectional imaging, including MRI, to evaluate for more extensive disease that may merit change in radiation field, extended androgen deprivation therapy, or guiding surgical planning. Although MRI offers reasonable performance characteristics to evaluate bone metastases, guidelines continue to support the use of bone scintigraphy. Emerging imaging technologies, including coupling positron emission tomography (PET) with MRI, have the potential to improve the accuracy of prostate cancer staging with the use of novel radiotracers.

Secondary Immune Thrombocytopenia in Metastatic Renal Cell Carcinoma: A Case Report and Discussion of the Literature

Immune thrombocytopenia (ITP) is a rare paraneoplastic syndrome of solid tumor malignancies. In previously described cases of renal cell carcinoma (RCC) associated with secondary ITP, treatment has consisted of nephrectomy, splenectomy, and corticosteroids. Here, we describe a case of metastatic RCC presenting with a right ventricular mass and subsequent development of secondary ITP. The clinical course was complicated by recurrent severe thrombocytopenia despite treatment with corticosteroids, rituximab, and thrombopoietin receptor agonists, precluding cancer-directed therapy and anticoagulation. Further study is needed to determine the optimal management strategy for malignancy-associated ITP.

Pilot Study of [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET)/Magnetic Resonance Imaging (MRI) for Staging of Muscle-invasive Bladder Cancer (MIBC)

INTRODUCTION

Computed tomography (CT) has limited diagnostic accuracy for staging of muscle-invasive bladder cancer (MIBC). [¹⁸F] Fluorodeoxyglucose positron emission tomography (FDG-PET)/magnetic resonance imaging (MRI) is a novel imaging modality incorporating functional imaging with improved soft tissue characterization. This pilot study evaluated the use of preoperative FDG-PET/MRI for staging of MIBC.

PATIENTS AND METHODS

Twenty-one patients with MIBC with planned radical cystectomy were enrolled. Two teams of radiologists reviewed FDG-PET/MRI scans to determine: (1) presence of primary bladder tumor; and (2) lymph node involvement and distant metastases. FDG-PET/MRI was compared with cystectomy pathology and computed tomography (CT).

RESULTS

Eighteen patients were included in the final analysis, most (72.2%) of whom received neoadjuvant chemotherapy. Final pathology revealed 10 (56%) patients with muscle invasion and only 3 (17%) patients with lymph node involvement. Clustered analysis of FDG-PET/MRI radiology team reads revealed a sensitivity of 0.80 and a specificity of 0.56 for detection of the primary tumor with a sensitivity of 0 and a specificity of 1.00 for detection of lymph node involvement when compared with cystectomy pathology. CT imaging demonstrated similar rates in evaluation of the primary tumor (sensitivity, 0.91; specificity, 0.43) and lymph node involvement (sensitivity, 0; specificity, 0.93) when compared with pathology.

CONCLUSIONS

This pilot single-institution experience of FDG-PET/MRI for preoperative staging of MIBC performed similar to CT for the detection of the primary tumor; however, the determination of lymph node status was limited by few patients with true pathologic lymph node involvement. Further studies are needed to evaluate the potential role for FDG-PET/MRI in the staging of MIBC.

Pilot study of [18F] fluorodexoyglucose positron emission tomography-magnetic resonance imaging (FDG-PET-MRI) for staging of muscle-invasive bladder cancer

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Background: Standard of care imaging for staging MIBC is computed tomography (CT) abdomen and pelvis despite poor diagnostic accuracy. The addition of FDG-PET to evaluate biologic activity has been shown to improve detection of metastatic bladder cancer. Better soft tissue characterization with MRI may improve detection of local disease. We hypothesized that simultaneous acquisition of FDG-PET and MRI images (PET-MRI) would allow for more accurate preoperative staging in patients with MIBC. Methods: 21 patients with MIBC and planned radical cystectomy with lymph node dissection were enrolled. Four radiologists (2 senior, 2 junior) with expertise in MRI and PET independently reviewed MRI and FDG-PET scans, respectively, to determine: 1) extent of the primary bladder tumor; and 2) involvement of local lymph nodes and distant sites of disease. Combined radiologist reads were performed (senior MRI and junior PET and vice versa). Imaging results were compared to surgical pathology. Results: 18 patients were included in the final analysis (3 PET-MRI scans excluded due to technical pitfalls with image acquisition). Final pathology revealed 10 patients (56%) with muscle invasion and only 2 patients (11%) with lymph node involvement. Combined analyses of PET-MRI accurately detected the extent of the primary tumor (sensitivity 0.84, specificity 0.50, PPV 0.70, NPV 0.70), but was less accurate for the detection of lymph node involvement (sensitivity 0.00, specificity 1.00, no calculable PPV, NPV 0.91). Senior MRI radiologist had improved PPV and NPV for extent of primary tumor compared to junior MRI radiologist (PPV 0.71 vs 0.56, NPV 0.83 vs. 0.50), and senior PET radiologist had improved PPV with similar NPV for extent of primary tumor (PPV 1.00 vs 0.78, NPV 0.50 vs 0.55). No patient was determined to have distant metastatic disease. Conclusions: To our knowledge, this is the first study exploring the use of PET-MRI for staging MIBC. This novel imaging modality demonstrated promise in detecting the extent of the primary tumor. Further investigation of FDG-PET-MRI is needed to better determine its potential utility in staging MIBC.

Comprehensive radiogenomics analysis of qualitative and quantitative features of cross-sectional imaging in the TCGA project in MIBC

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Background: Quantitative imaging descriptors derived from CT and MRI can be integrated with genomic data that may be used as non-invasive prognostic or predictive biomarkers. We report an integrated radiogenomics project designed to develop subjective and objective parameters extracted from cross-sectional imaging of MIBC from studies archived in the TCIA and linked to the TCGA project. Methods: We reported comprehensive integrated genomic analysis of 412 tumors (Cell 2017). 7 of 33 tissue source sites submitted CT scans to the TCIA (n=106). We developed 17 features describing tumor size/location, metastases sites, and tumor morphology; 9 GU radiologists reviewed the scans in a blinded manner. EH analyzed the data independent of the radiologists. We computed kappa statistics for categorical features and coverage probabilities for quantitative features (Lin et al 2002). The tumor was segmented on an axial image and the segmented image analyzed using a radiomics panel (radiomicslab.usc.edu). Associations between individual features and subtypes were assessed (Fisher’s Exact Test) for categorical features and Kruskal-Wallis Test for quantitative features. Results: Substantial agreement (k≥ 0.6) was observed in 4 features: tumor laterality, tumor within bladder diverticulum, right and left UVJ involvement and hydroureter. We observed weak agreement (95% CI <0.4) for bladder neck, posterior bladder, dome, and trigone involvement, tumor margin, internal architecture, radiographic stage, left upper tract involvement, and metastases. The coverage probability for lesion size was 0.59 (0.544-0.638) (Figure). Tumor morphology was associated with microRNA cluster, with diffuse wall thickening having a higher tendency toward Clusters 3 and 4 (p < .001). Radiomic analysis identified statistically significant associations of mutations in FGFR3, CREBBP, CASP8 and EP300 with multiple radiomic features. Conclusions: This blinded comprehensive assessment of features extracted from CT images highlights many of the ongoing challenges in staging patients with MIBC. Preliminary analysis shows promise in analyzing associations between radiomic features and mutations.

MRI in pregnancy: Indications and practical considerations

There is a constantly evolving knowledgebase regarding the safety of MRI in pregnant patients, as well as the safety of gadolinium administration, given potential fetal risks. This review provides an overview of national and international recommendations for patient screening and safety by trimester, evaluates the most recent literature regarding administration of gadolinium in pregnant patients, and discusses technical requirements when imaging pregnant patients. A protocol for imaging pregnant patients is provided, and multiple common indications for MRI in pregnancy are discussed. Level of Evidence 5. Technical Efficacy Stage 5. J. Magn. Reson. Imaging 2019;49:621-631.

PROTECTIVE EFFECT OF NIGELLA SATIVA OIL ON MYOCARDIUM IN STREPTOZOTOCIN-INDUCED DIABETIC RATS

Background

To evaluate the protective effect of Nigella sativa oil (NSO) on the myocardium in streptozotocin-induced diabetic rats.

Materials and methods

Thirty-two 7-8-week-old female Wistar albino rats (300-350 g) were equally divided into 4 groups: nondiabetic untreated animals (control), diabetes mellitus (DM), NSO, and DM+NSO groups. For the induction of diabetes, 45 mg/kg streptozotocin was applied to the rats in the DM and DM+NSO groups as a single intraperitoneal dose. NSO (400 mg/kg) was orally administered through an intragastric catheter once a day over 21 days. Formalin-fixed, paraffin-embedded tissue sections of the myocardium were evaluated histopathologically and immunohistochemically.

Results

Compared to the control, NSO, and DM+NSO groups, the myocardial tissue samples from the rats in the DM group had significantly higher myositis, hyaline degeneration, and Zenker's necrosis. Moreover, the Bcl-2 expressions were significantly higher in the control, NSO, and DM+NSO groups than in the DM group.

Conclusion

NSO has a protective effect on the myocardium of streptozotocin-induced diabetic rats, most likely via suppressing apoptosis.

Multiparametric Magnetic Resonance Imaging for Bladder Cancer: Development of VI-RADS (Vesical Imaging-Reporting And Data System)

CONTEXT

Management of bladder cancer (BC) is primarily driven by stage, grade, and biological potential. Knowledge of each is derived using clinical, histopathological, and radiological investigations. This multimodal approach reduces the risk of error from one particular test, but may present a staging dilemma when results conflict. Multiparametric magnetic resonance imaging (mpMRI) may improve patient care through imaging of the bladder with better resolution of the tissue planes than computed tomography and without radiation exposure.

OBJECTIVE

To define a standardized approach to imaging and reporting mpMRI for BC, by developing a VI-RADS score.

EVIDENCE ACQUISITION

We created VI-RADS (Vesical Imaging-Reporting And Data System) through consensus using existing literature.

EVIDENCE SYNTHESIS

We describe standard imaging protocols and reporting criteria (including size, location, multiplicity, and morphology) for bladder mpMRI. We propose a five-point VI-RADS score, derived using T2-weighted MRI, diffusion-weighted imaging, and dynamic contrast enhancement, which suggests the risks of muscle invasion. We include sample images used to understand VI-RADS.

CONCLUSIONS

We hope that VI-RADS will standardize reporting, facilitate comparisons between patients, and in future years, will be tested and refined if necessary. While we do not advocate mpMRI for all patients with BC, this imaging may compliment pathology or reduce radiation-based imaging. Bladder mpMRI may be most useful in patients with non-muscle-invasive cancers, in expediting radical treatment or for determining response to bladder-sparing approaches.

PATIENT SUMMARY

Magnetic resonance imaging (MRI) scans for bladder cancer are becoming more common and may provide accurate information that helps improve patient care. Here, we describe a standardized reporting criterion for bladder MRI. This should improve communication between doctors and allow better comparisons between patients.

MRI features of primary rare malignancies of the liver: A report from four university centres

PURPOSE

To determine if rare primary malignancies of the liver may have consistent features on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

This IRB-compliant retrospective study reviewed the records from the pathology departments of four university centres over an 11-year period from 2005-2016 to identify rare primary malignant tumours, which were cross-referenced with MRI records. MRI studies of these patients were reviewed to determine if these tumours exhibited consistent and distinctive features.

RESULTS

Sixty patients were identified with rare primary liver tumours. The following distinctive features and frequency of occurrence were observed: mixed hepatocellular carcinoma-cholangiocarcinoma showed regions of wash-out in 7/19 of patients; 6/6 of fibrolamellar carcinomas demonstrated large heterogeneous lesions with large heterogeneous central scars; epithelioid haemangioendothelioma larger than 2 cm showed target-like enhancement in late-phase enhancement in 9/13; sarcomas excluding angiosarcoma had central necrosis in 3/9 and haemorrhage in 5/9; angiosarcomas showed centripedal progressive nodular enhancement in 3/6 and showed regions of haemorrhage in 3/6; and 7/7 of primary hepatic lymphomas showed encasement of vessels.

CONCLUSION

Although helpful features for the differentiation of rare primary malignancies of the liver are identified, no MRI features appear to be specific and therefore histopathological confirmation is usually required for definitive diagnosis.

KEY POINTS

• No MRI features appear to be specific for rare primary liver malignancies. • Haemorrhage is a helpful sign in diagnosis of primary hepatic sarcomas. • Angiosarcomas may show progressive nodular enhancement towards the centre mimicking haemangioma. • Vessel encasement is a helpful sign in diagnosis of primary hepatic lymphoma.

Diagnostic accuracy of contrast-enhanced ultrasound for characterization of kidney lesions in patients with and without chronic kidney disease

BACKGROUND

Patients with chronic kidney disease are at increased risk of cystic kidney disease that requires imaging monitoring in many cases. However, these same patients often have contraindications to contrast-enhanced computed tomography and magnetic resonance imaging. This study evaluates the accuracy of contrast-enhanced ultrasound (CEUS), which is safe for patients with chronic kidney disease, for the characterization of kidney lesions in patients with and without chronic kidney disease.

METHODS

We performed CEUS on 44 patients, both with and without chronic kidney disease, with indeterminate or suspicious kidney lesions (both cystic and solid). Two masked radiologists categorized lesions using CEUS images according to contrast-enhanced ultrasound adapted criteria. CEUS designation was compared to histology or follow-up imaging in cases without available tissue in all patients and the subset with chronic kidney disease to determine sensitivity, specificity and overall accuracy.

RESULTS

Across all patients, CEUS had a sensitivity of 96% (95% CI: 84%, 99%) and specificity of 50% (95% CI: 32%, 68%) for detecting malignancy. Among patients with chronic kidney disease, CEUS sensitivity was 90% (95% CI: 56%, 98%), and specificity was 55% (95% CI: 36%, 73%).

CONCLUSIONS

CEUS has high sensitivity for identifying malignancy of kidney lesions. However, because specificity is low, modifications to the classification scheme for contrast-enhanced ultrasound could be considered as a way to improve contrast-enhanced ultrasound specificity and thus overall performance. Due to its sensitivity, among patients with chronic kidney disease or other contrast contraindications, CEUS has potential as an imaging test to rule out malignancy.

TRIAL REGISTRATION

This trial was registered in clinicaltrials.gov, NCT01751529 .

Magnetic resonance imaging of the cirrhotic liver: diagnosis of hepatocellular carcinoma and evaluation of response to treatment - Part 2

In the second part of this review, we will describe the ancillary imaging features of hepatocellular carcinoma (HCC) that can be seen on standard magnetic resonance imaging (MRI) protocol, and on novel and emerging protocols such as diffusion weighted imaging and utilization of hepatocyte-specific/hepatobiliary contrast agent. We will also describe the morphologic sub-types of HCC, and give a simplified non-invasive diagnostic algorithm for HCC, followed by a brief description of the liver imaging reporting and data system (LI-RADS), and MRI assessment of tumor response following locoregional therapy.

Magnetic resonance imaging of the cirrhotic liver: diagnosis of hepatocellular carcinoma and evaluation of response to treatment - Part 1

Magnetic resonance imaging (MRI) is the modern gold standard for the noninvasive evaluation of the cirrhotic liver. The combination of arterial phase hyperenhancement and delayed wash-out allows a definitive diagnosis of hepatocellular carcinoma (HCC) in patients with liver cirrhosis or chronic liver disease, without the requirement for confirmatory biopsy. That pattern is highly specific and has been endorsed in Western and Asian diagnostic guidelines. However, the sensitivity of the combination is relatively low for small HCCs. In this two-part review paper, we will address MRI of the cirrhotic liver. In this first part, we provide a brief background on liver cirrhosis and HCC, followed by descriptions of imaging surveillance of liver cirrhosis and the diagnostic performance of the different imaging modalities used in clinical settings. We then describe some of the requirements for the basic MRI technique, as well as the standard MRI protocol, and provide a detailed description of the appearance of various types of hepatocellular nodules encountered in the setting of the carcinogenic pathway in the cirrhotic liver, ranging from regenerative nodules to HCC.

An overview of imaging techniques for liver metastases management

Evaluation of liver metastases is one of the most common indications for liver imaging. Imaging plays a key role in the of assessment liver metastases. A variety of imaging techniques, including ultrasonography, computed tomography, MRI and PET combined with CT scan are available for diagnosis, planning treatment, and follow-up treatment response. In this paper, the authors present the role of imaging for the assessment of liver metastases and the contribution of each of the different imaging techniques for their evaluation and management. Following recent developments in the field of oncology, the authors also present the importance of imaging for the assessment of liver metastases response to therapy. Finally, future perspectives on imaging of liver metastases are presented.

Surrogate arterial phase imaging using a long duration (≈1.5 min) radial acquisition T1-weighted sequence: an alternative in patients unable to breath-hold

BACKGROUND

Pediatric and adult patients unable to suspend respiration generally undergo magnetic resonance (MR) examinations that lack arterial phase imaging, which is a phase that provides substantial information on disease processes. An MR strategy that provides this type of information may be of considerable value.

PURPOSE

To describe and assess the feasibility and enhancement quality of early-phase imaging utilizing long-duration radial 3D-GRE imaging by initiating the sequence prior to starting contrast injection.

MATERIAL AND METHODS

Thirty-three consecutive patients (10 men, 23 women; 50.7 ± 25.5 years) underwent free-breathing gadolinium-enhanced radial 3D-GRE, with sequence initiation 30 s prior to contrast injection. Late hepatic arterial (LHA) phase was chosen for comparison. Images were evaluated for enhancement and overall image quality. Organ enhancement was calculated. Sub-group analysis was performed.

RESULTS

Twenty-two examinations of radial 3D-GRE sequences were acquired during the LHA phase. Organ enhancement scores were of satisfactory to good quality (range, 3.32-3.82). There was a significant trend of superior overall enhancement quality scores in pediatrics and examinations performed at 3 T (P = 0.0225 and 0.0001, respectively).

CONCLUSION

Arterial phase abdominal MR imaging is feasible using conventional radial 3D-GRE by adopting this simplistic proposed approach, which may allow arterial-phase imaging in patients unable to breath-hold.

Comparison of Doppler ultrasound and transient elastography in the diagnosis of significant fibrosis in patients with nonalcoholic steatohepatitis

BACKGROUND

Liver fibrosis is an important prognostic determinant in patients with nonalcoholic steatohepatitis (NASH). Hepatic artery resistivity index (HARI) is a doppler ultrasonography (US) parameter that is used to follow up microcirculatory resistance in fatty liver. We aimed to asses whether it is possible to demonstrate significant fibrosis by means of doppler US in comparison with transient elastography (TE) and liver biopsy in NASH patients.

PATIENTS AND METHODS

A total of 63 (mean age 47.1 ± 8.4 years, 39 male, 24 female) biopsy-proven NASH patients were enrolled in this prospective study. The study population was classified into two groups: significant and no-significant fibrosis patients. Doppler US and TE were performed in two groups.

RESULTS

HARI and TE values were significantly higher in significant fibrosis group (0.81 ± 0.05 vs. 0.63 ± 0.14, p < 0.0005; 15.9 ± 4.8 vs. 6.2 ± 2.6 kilopascals, p < 0.0005; respectively). Based on the ROC curve, the optimal cut-off value of HARI for a significant fibrosis was >0.75, which yielded a sensitivity of 78% and a specificity of 75%, with the area under the curve at 0.90. The optimal cut-off value of TE for a significant fibrosis was >9.8 kilopascals, which yielded a sensitivity of 90% and a specificity of 91%, with the area under the curve at 0.95. HARI values were moderately correlated with TE values (r = 0.53, p < 0.001).

CONCLUSION

Doppler US has moderate % sensitivity and % specificity, which is lower compared with TE for the diagnosis significant fibrosis. However, it may be used as an alternative method for the assessment of fibrosis in patients with NASH who are not good candidates for TE evaluation.

Mass-forming cholangiocarcinoma and adenocarcinoma of unknown primary: can they be distinguished on liver MRI?

PURPOSE

To determine MR features suggestive of mass-forming cholangiocarcinoma (CCA) or liver metastases of adenocarcinoma of unknown primary (AUP), and to compare the ability of two experienced radiologists to establish the correct diagnosis.

MATERIALS AND METHODS

61 patients with CCA or AUP, with MRIs were placed into two groups: population 1, 28 patients with certain diagnosis of either CCA or AUP; and population 2, 33 patients with uncertain diagnosis. Using population 1 with known diagnosis, two investigators formulated imaging criteria for CCA or AUP, which represented phase 1 of the study. In phase 2, two independent radiologists categorized the patients in populations 1 and 2 as CCA or AUP using the formulated criteria. This categorization was compared with the patient medical records and pathologist review. Findings were tested for statistical significance.

RESULTS

In phase 1, solitary lesion, multifocal lesions with dominant lesion, capsule retraction, and porta hepatis lymphadenopathy were features of CCA; multifocal lesions with similar size, and ring enhancement were features of AUP. The number of lesions, capsule retraction, and early tumor enhancement pattern were observed to be significant features (P < 0.05). In phase 2, agreement between the two radiologists was good (k = 0.663). For population 1, the agreement was good (k = 0.659), and was fair for population 2 (k = 0.293). Concordance between the two radiologists, medical record, and the pathologist was found in 41/61 (67%) patients.

CONCLUSION

Distinctive features of CCA and AUP are identifiable on MRI images, which may aid the radiologist to establish the correct diagnosis.

Gastrointestinal imaging-practical magnetic resonance imaging approach

Over the past two decades, advances in cross-sectional imaging such as computed tomography and magnetic resonance imaging (MRI) have dramatically changed the concept of gastrointestinal imaging. MR is playing an increasing role in the evaluation of gastrointestinal disorders. MRI combines the advantages of excellent soft-tissue contrast, noninvasiveness, functional information and lack of ionizing radiation. Furthermore, recent developments of MRI have led to improved spatial and temporal resolution as well as decreased motion artifacts. In this article we describe the technical aspects of gastrointestinal MRI and present a practical approach for a well-known spectrum of gastrointestinal disease processes.

Ressonância Magnética em Doentes Grávidas com Suspeita de Embolia Pulmonar: Steady-State Free Precession vs 3D-GRE Após Gadolínio

Introdução: A embolia pulmonar é uma importante causa de mortalidade materna no mundo desenvolvido. A cintigrafia de ventilaçãoperfusãoe a tomografia computorizada causam exposição à radiação ionizante. A ressonância magnética com contraste-gadolínioendovenoso não é geralmente indicada em doentes grávidas. A RM utilizando técnicas resistentes aos artefactos de movimento, quenão usam contraste endovenoso, como a balanced steady-state free precession (SSFP) poderá ser uma abordagem preferível emdoentes grávidas.Objectivo: Descrever os achados preliminares do uso de SSFP na avaliação de doentes grávidas com suspeita de EP, comparandocom uma população de jovens mulheres avaliadas com RM 3D-gradiente eco após contraste-gadolínio pela mesma suspeita clínica.Materiais e Métodos: O arquivo radiológico foi retrospectivamente analisado para dois grupos de doentes submetidos a RM do tóraxem 1.5T por suspeita de EP, entre Janeiro de 2007 e Junho de 2010: grávidas com RM incluindo SSFP (grupo A) e mulheres comidade inferior a 45 anos com RM incluindo sequência ponderada em T1, 3D-GRE, após contraste-gadolínio (grupo B). A populaçãofinal incluiu 21 doentes. As imagens de RM foram avaliadas com leitura independente e cega, para qualidade de imagem do sistemaarterial pulmonar, EP e outros achados torácicos. Os dados foram submetidos a análise estatística.Resultados: A qualidade de imagem foi considerada boa em todas as artérias centrais e lobares de ambos os grupos e em pelo menos90% (grupo A) e 83,3% (grupo B) das artérias segmentares. Não ocorreram diferenças significativas na qualidade de imagem dasartérias pulmonares centrais e lobares entre os grupos A e B (p > 0,05).Conclusão: A RM com SSFP pode visualizar as artérias pulmonares centrais, lobares e segmentares em doentes grávidas, comqualidade de imagem adequada e comparável a 3D-GRE.

MRI of pregnant patients for suspected pulmonary embolism: steady-state free precession vs postgadolinium 3D-GRE

INTRODUCTION

Pulmonary embolism is a leading cause of maternal mortality in the developed world. Ventilation-perfusion scintigraphy and Computer tomography cause ionizing radiation exposure. Gadolinium-enhanced magnetic resonance imaging is generally not indicated in pregnant patients. MRI using motion resistant techniques that do not use intravenous contrast material, such as balanced steady-state free precession may be a better approach in pregnant patients.

PURPOSE

To describe the preliminary findings of the use of SSFP for the evaluation of pregnant patients with suspected PE, and to compare with a young women population evaluated with postgadolinium 3D-gradient echo sequences for the same intention.

MATERIALS AND METHODS

Radiology database was searched for two groups of subjects who underwent chest MRI at 1.5T for suspected PE, between January, 2007 and June, 2010: pregnant patients with MRI including balanced SSFP (group A) and females younger than 45 years old including a T1-weighted postgadolinium 3D-GRE (group B) sequence. The final study population consisted of 21 subjects. Blind and independent evaluation of MR images was performed for image quality of the pulmonary arterial system, PE and other chest findings. Data was subject to statistical analysis.

RESULTS

Good image quality was observed in all central and lobar arteries on both groups and in 90% (group A) and at least 83.3% (group B) of the segmental arteries. There was no significant difference between groups A and B for image quality of central and lobar pulmonary arteries (p > 0.05).

CONCLUSION

SSFP can visualize central, lobar and segmental pulmonary arteries with sufficient image quality in pregnant patients, comparable to 3D-GRE.

Knee joint examinations by magnetic resonance imaging: The correlation of pathology, age, and sex

Aims:

The aim of our study was to investigate the incidence and coexistence of multiple knee joint pathologies and the distribution of knee joint pathologies according to age and sex.

Patients and Methods:

A retrospective analysis was performed using the clinical data of patients evaluated with magnetic resonance imaging (MRI) of the knee joint. Data from 308 patients examined between August 2002 and July 2003 were included into this study. A Pearson correlation analysis was performed to examine the relationship between the pathological findings and the age and sex of the patients.

Results:

The ages of the patients ranged between 1 and 74 years (mean: 43.3 years). Age was significantly correlated with meniscal degeneration and tears, medial collateral ligament degeneration, parameniscal cyst, and chondromalacia patellae. There was a significant correlation between male gender and anterior cruciate ligament injury. Meniscal injury was significantly correlated with bursitis, as well as medial collateral ligament injury. Bone bruise was significantly correlated with medial collateral ligament injury, lateral collateral ligament injury, Baker's cyst, and anterior cruciate ligament injury. Chondromalacia patellae was significantly correlated with anterior cruciate ligament injury, patellae alta, and osteochondral lesion. Bursitis (in 53.2% of the patients) followed by grade-II meniscal degeneration (in 43% of the patients) were the most common knee pathologies observed by MRI.

Conclusions:

MRI findings of select knee pathologies are significantly correlated with each other and the age and sex of the patient.

Space occupying lesions in the fetal chest evaluated by MRI

Background

The most common space occupying lesions of the fetal thorax are congenital diaphragmatic hernia (CDH), congenital cystic adenomatoid malformation (CCAM), and bronchopulmonary sequestration (BPS). Although applications of prenatal MRI have been vastly improved in the recent years, its use in the assessment of space occupying lesions of the fetal chest differs among centers.

Objectives

To evaluate MRI findings in the diagnosis and follow-up of space-occupying lesions in the fetal chest with the review of relevant literature.

Patients and Methods

The fetuses with space-occupying lesions of the chest were retrieved from our 1.5T fetal MRI database of 347 patients. MRI features including the shape, signal characteristics, feeding artery, margin, mass effect, affected organ parts and anatomic location were reviewed. The results were correlated with the pathology results, follow-up and surgical findings.

Results

Nineteen MR images of 17 fetuses (mean gestational age, 23.8 weeks) with spaceoccupying lesions (5 CCAMs including one involuted case), 2 BPSs, 2 hybrid lesions, 8 CDH) were evaluated. One case of CCAM completely involuted in utero, four newborns were operated, and the resulting 12 fetuses were terminated. The surgical and pathological findings were in accordance with MRI findings.

Conclusion

MRI can reliably differentiate CDH from CCAM and BPS in utero. Follow-up is of utmost importance as lesions may involute or progress in utero. Prenatal MRI findings help postnatal decision-making, surgical planning and parental counseling.

Graduating 4th year radiology residents' perception of optimal imaging modalities for neoplasm and trauma: a pilot study from four U.S. universities

OBJECTIVE: Our purpose was to assess 4th year radiology residents' perception of the optimal imaging modality to investigate neoplasm and trauma. MATERIALS AND METHODS: Twenty-seven 4th year radiology residents from four residency programs were surveyed. They were asked about the best imaging modality to evaluate the brain and spine, lungs, abdomen, and the musculoskeletal system. Imaging modalities available were MRI, CT, ultrasound, PET, and X-ray. All findings were compared to the ACR appropriateness criteria. RESULTS: MRI was chosen as the best imaging modality to evaluate brain, spine, abdominal, and musculoskeletal neoplasm in 96.3%, 100%, 70.4%, and 63% of residents, respectively. CT was chosen by 88.9% to evaluate neoplasm of the lung. Optimal imaging modality to evaluate trauma was CT for brain injuries (100%), spine (92.6%), lung (96.3%), abdomen (92.6%), and major musculoskeletal trauma (74.1%); MRI was chosen for sports injury (96.3%). There was agreement with ACR appropriateness criteria. CONCLUSION: Residents' perception of the best imaging modalities for neoplasm and trauma concurred with the appropriateness criteria by the ACR.

Primary peritoneal spindle cell sarcoma presented with massive ascites: a case report

Soft tissue sarcomas (STSs) are a heterogeneous group of rare neoplasms originating from the embryonic mesoderm and mesenchymal cells. Primary peritoneal sarcomas have been reported as leiomyosarcoma, liposarcoma and carcinosarcoma. However, primary peritoneal spindle cell sarcoma has never been reported in the literature. Herein, we report on a 38-year-old woman with massive ascites diagnosed as primary peritoneal spindle cell sarcoma. Following doxorubicin and ifosfamide chemotherapy, her symptoms improved and ascites regressed. Other primary peritoneal sarcomas rarely cause massive ascites. We suggest that in patients presenting with massive exudative ascites associated with malignancy, primary peritoneal sarcomas should be also considered in the differential diagnosis.

Nephrogenic systemic fibrosis and management of high-risk patients

The purpose of this work is to provide current information on the rapidly evolving subject of nephrogenic systemic fibrosis (NSF), to establish the radiologic approach to the management of high-risk patients for NSF, and to assess the probabilistic risk of NSF compared to contrast induced nephropathy (CIN), as encountered with iodinated contrast media used in computed tomographic (CT) imaging. NSF is a disease process of considerable concern following gadolinium-containing contrast agents (GCCA) exposure in patients with diminished renal function. To minimize the possibility of NSF development in high-risk patients, GGCAs should not be used when they are not necessary, or the GCCAs, that have not at present been associated with NSF development, should be used at the lowest possible diagnostic dose, when they are necessary. Contrast-induced nephropathy is also a great risk in this patient population following the adminstration of iodinated contrast media (CM). In patients with diminished renal function who are not on regular dialysis, the risk of CIN following the administration of iodinated CM is higher than the risk of NSF following the administration of the most stable GCCAs. Risk benefit analysis should be performed prior to the administration of all CM, and the best combination of safety and diagnostic accuracy should be sought. Concern of NSF or CIN should not prevent the use of contrast agents in magnetic resonance imaging or computed tomography when they are deemed essential.

Quantitative and qualitative comparison of 1.5 and 3.0 Tesla MRI in patients with chronic liver diseases

PURPOSE

To compare the quantitative and qualitative image quality intra-individually, at 1.5 and 3.0 Tesla (T) in patients with chronic liver diseases.

MATERIALS AND METHODS

The study group included 24 consecutive patients (17 males, 7 females; mean age +/- standard deviation 56.5 +/- 11.5) who had chronic liver diseases and underwent abdominal MRI for the liver evaluation at both 1.5 and 3.0 T within a 4-month period. All MRI studies were retrospectively evaluated quantitatively and qualitatively. Quantitative analysis was performed by measuring signal to noise ratio (SNR) on various abdominal organs. Qualitative analysis was performed by two reviewers to assess image quality, artifacts, and imaging findings of chronic liver diseases. Quantitative and qualitative analyses findings were compared between 1.5 and 3.0 T using the paired Student t-test and Wilcoxon signed rank test, respectively.

RESULTS

The statistically significant increase in SNRs in various abdominal tissues ranged from 1.3- to 3.5-fold at 3.0 T compared to 1.5 T. Three-dimensional gradient echo (3D-GE) sequences demonstrated significantly higher image quality at 3.0 T (P < 0.01), whereas precontrast spoiled gradient echo (SGE) sequences demonstrated significantly higher image quality at 1.5 T (P < 0.01). T2-weighted sequences did not show any significant difference in image quality between 1.5 and 3.0 T (P > 0.05).

CONCLUSION

The SNRs of various abdominal tissues demonstrated significant increases at 3.0 T. The image quality of 3D-GE sequences was higher at 3.0 T, whereas the image quality of precontrast SGE sequences was higher at 1.5T.

MRI findings in nonalcoholic steatohepatitis: correlation with histopathology and clinical staging

PURPOSE

To evaluate magnetic resonance imaging (MRI) findings of nonalcoholic steatohepatitis (NASH) and to determine the correlation of MRI findings with histopathology and Mayo End-Stage Liver Disease (MELD) score.

MATERIALS AND METHODS

Thirty patients (18 males, 12 females; mean age: 57+/-8.9 years; age range: 35-71 years) with histopathologically proven NASH who underwent MRI examinations between January 2001 and October 2005 were included in the study. Two radiologists retrospectively reviewed all magnetic resonance (MR) examinations in consensus to evaluate the presence and extent of predetermined findings of NASH including liver steatosis, early patchy liver enhancement indicating inflammation and liver fibrosis. The findings detected on MRI were correlated and compared to histopathological findings and MELD score by using nonparametric Spearman correlation coefficient and Kruskal-Wallis analysis of variance.

RESULTS

Liver steatosis was observed in 10 of 30 patients; early patchy liver enhancement, in 8 of 30 patients and liver fibrosis in 19 of 30 patients on MR images. Liver fibrosis was reticular in all these patients. There were statistically significant moderate correlations between MRI findings of liver steatosis and histopathologic grades of steatosis (r=0.43; P<.05), and between MRI findings of fibrosis and histopathologic stages of fibrosis (r=0.61; P<.001). Early patchy enhancement did not demonstrate statistically significant correlation with inflammation (P=.28). There was no statistically significant overall correlation between MRI findings of NASH and MELD score.

CONCLUSION

MRI findings of liver steatosis and fibrosis in NASH showed moderate correlations with histopathologic grades of steatosis and stages of fibrosis, but MRI findings of NASH did not demonstrate any significant correlations with MELD score.

Early contrast enhancement of the liver: exact description of subphases using MRI

PURPOSE

The purpose of this study was to describe the subphases of early post-contrast enhancement of the liver, using vessel enhancement patterns, and correlate these findings with enhancement patterns of abdominal organs.

MATERIALS AND METHODS

A total of 114 patients who underwent gadolinium-enhanced abdominal magnetic resonance imaging examinations constituted the final study group, of which 56 were women (age range, 3-94 years; mean, 50 years) and 58 were men (age range, 6-85 years; mean, 54 years). Early post-contrast sequences in all patients were evaluated retrospectively by two reviewers for the determination of the presence of contrast enhancement in predetermined major vessels of the abdomen and qualitative and quantitative extent of enhancement of the renal cortex, spleen, pancreas and liver. Based on the overall findings, subphases of early contrast enhancement of the liver were described and quantitative extent of enhancement of organs was correlated with subphases of early contrast enhancement of the liver. Mann-Whitney U test and one-way unbalanced analysis of variance tests were used for the comparisons.

RESULTS

Early hepatic arterial phase was observed in 14/114 patients, mid-hepatic arterial phase in 23/114 patients, late hepatic arterial phase in 33/114 patients, splenic vein only hepatic arterial dominant phase in 20/114 patients and hepatic arterial dominant phase in 24/114 patients. There was an overall association between the subphases of enhancement and the quantitative extent of enhancement for all studied organs (P<.0001).

CONCLUSION

The evaluation of vessel and organ enhancement patterns has allowed the characterization of five different subphases in early post-contrast enhancement of the liver. The quantitative extent of enhancement of abdominal organs also demonstrated significant correlation with these five subphases.

Water excitation MPRAGE: an alternative sequence for postcontrast imaging of the abdomen in noncooperative patients at 1.5 Tesla and 3.0 Tesla MRI

PURPOSE

To evaluate the diagnostic image quality of postgadolinium water excitation-magnetization-prepared rapid gradient-echo (WE-MPRAGE) sequence in abdominal examinations of noncooperative patients at 1.5 Tesla (T) and 3.0T MRI.

MATERIALS AND METHODS

Eighty-nine consecutive patients (48 males and 41 females; mean age +/- standard deviation, 54.6 +/- 16.6 years) who had MRI examinations including postgadolinium WE-MPRAGE were included in the study. Of 89 patients, 33 underwent noncooperative protocol at 1.5T, 10 underwent noncooperative protocol at 3.0T, and 46 underwent cooperative protocol at 3.0T. Postgadolinium WE-MPRAGE, MPRAGE, and three-dimensional gradient-echo sequences of these three different groups were qualitatively evaluated for image quality, extent of artifacts, lesion conspicuity, and homogeneity of fat-attenuation by two reviewers retrospectively, independently, and blindly. The results were compared using Wilcoxon signed rank and Mann-Whitney U tests. Kappa statistics were used to measure the extent of agreement between the reviewers.

RESULTS

The average scores indicated that the images were diagnostic for WE-MPRAGE at 1.5T and 3.0T in noncooperative patients. WE-MPRAGE achieved homogenous fat-attenuation in 31/33 (94%) of noncooperative patients at 1.5T and 10/10 (100%) of noncooperative patients at 3.0T. WE-MPRAGE at 3.0T had better results for image quality, extent of artifacts, lesion conspicuity and homogeneity of fat-attenuation compared with WE-MPRAGE at 1.5T, in noncooperative patients (P = 0.0008, 0.0006, 0.0024, and 0.0042; respectively). Kappa statistics varied between 0.76 and 1.00, representing good to excellent agreement.

CONCLUSION

WE-MPRAGE may be used as a T1-weighted postgadolinium fat-attenuated sequence in noncooperative patients, particularly at 3.0T MRI.

When should abdominal magnetic resonance imaging be used?

When assessing the use of an imaging study, historically 2 criteria were used, diagnostic accuracy and cost of the study. However, as the awareness of risk for radiation-induced cancer in the general population increases as a direct result of more computed tomography (CT) studies being performed, reevaluation of the approach to imaging studies is necessary. The new imaging paradigm considers patient safety as an important aspect of assessing the role of an imaging modality. The primary goals of the new imaging paradigm should be diagnostic accuracy and patient safety, with the secondary goal being more affordable cost of study. In formulating a plan for when to use body magnetic resonance imaging (MRI), one has to consider all of these criteria and should also consider the question of when CT has unmatched diagnostic accuracy. The advantages of the spatial resolution of CT are mainly realized when there is great contrast between what is being looked for and background tissue; examples include small lung nodules and renal calculi. The greater intrinsic soft tissue contrast resolution and greater sensitivity for the presence or absence of intravenous contrast are appreciated in MRI studies, circumstances in which lesions occur within an organ without altering its exterior contour. This is well-shown for liver lesions. Adding patient safety into the equation, MRI should be indicated in exams in which there is no greater difference in diagnostic accuracy between CT and MRI, in patients with greater concern for radiation safety such as pediatric patients, and in cases of multiple or serial exams.

3.0-T MRI evaluation of patients with chronic liver diseases: initial observations

PURPOSE

To describe the use of 3.0-T magnetic resonance imaging (MRI) for the evaluation of chronic liver diseases.

MATERIALS AND METHODS

Two groups of patients who had chronic liver diseases and underwent 3.0-T MRI for evaluation of the liver were included in the study. The first group of patients included 66 consecutive patients (33 male, 33 female; mean age+/-standard deviation, 56+/-11). The second group of patients included 30 consecutive patients (18 males, 12 females; mean age+/-standard deviation, 53+/-10) in whom Variable-Rate Selective Excitation (VERSE) pulses and improved adjustments procedure were used during the acquisitions. Imaging findings of chronic liver diseases, predetermined artifacts and image quality of all individual sequences in the first group and predetermined artifacts and image quality of T2-weighted sequences in the second group were reviewed retrospectively and independently by two reviewers. chi-Square tests were used to compare the findings between two groups of patients and individual sequences. Kappa statistics were used to determine the extent of agreement between the reviewers.

RESULTS

Fifteen dysplastic nodules in 6 of 66 (9%) patients and 12 hepatocellular carcinomas in 11 of 66 (17%) patients were detected. Excluding motion artifacts, three-dimensional (3D) T1-weighted gradient-echo (GE) sequence was the least affected sequence by the artifacts. Image quality of T1-weighted 3D-GE sequences was excellent in 43 of 66 (65%) patients. In-phase and out-of-phase T1-weighted spoiled GE (SGE) images were fair in 62 of 66 (94%) and 61 of 66 (92%) patients, respectively. The image quality of short tau inversion recovery (STIR) and half-Fourier rapid acquisition with relaxation enhancement (RARE) sequences were fair in 31 of 66 (47%) and 53 of 66 (80%) patients. STIR and half-Fourier RARE sequences in the second group demonstrated significantly better image quality (P=.03 and P<.0001).

CONCLUSION

3.0-T MRI allows the acquisition of very high quality postgadolinium 3D-GE sequence, which permitted the detection and characterization of lesions in the setting of chronic liver diseases. The use of VERSE pulses and improved adjustments procedure improved the image quality of T2-weighted sequences. In-phase/out-of-phase SGE sequences are at present of fair quality.

Gadolinium- and superparamagnetic-iron-oxide-enhanced MR findings of intrapancreatic accessory spleen in five patients

PURPOSE

The purposes of this study were to describe dynamic gadolinium-enhanced magnetic resonance imaging (MRI) findings of intrapancreatic accessory spleen(s) (IPAS) in five patients and to show how superparamagnetic iron oxide (SPIO) enhancement can be used for definite characterization in two cases.

MATERIALS AND METHODS

An MRI database was searched for patients who had pancreatic tail lesions with imaging features compatible with IPAS between June 2005 and July 2007. Five (four male, one female) patients (age: mean+/-S.D., 58+/-9.8 years; range, 50-75 years) were identified. All patients were examined with standard gadolinium-enhanced MRI protocol. Additionally, two patients were examined with SPIO-enhanced MRI protocol. All MRI examinations were retrospectively and blindly evaluated by two radiologists for the predetermined findings, and their final diagnoses were noted.

RESULTS

One pancreatic tail lesion was detected in each patient. All of these lesions were single, focal, well-marginated and located within 3 cm of the distal tail of the pancreas. The mean size (mean+/-S.D.) of the lesions was (2.02+/-0.64)x(1.72+/-0.42) cm2, and all lesions had a rounded morphology. The signal intensity of all lesions was similar to that of the spleen on all sequences, including precontrast, postgadolinium and post-SPIO sequences. The reviewers confidently diagnosed IPAS in two patients who had SPIO-enhanced MRI. In the remaining three patients, the reviewers favored the diagnosis of IPAS based on the findings of standard gadolinium-enhanced MRI; however, they could not definitively exclude the other differential diagnoses.

CONCLUSION

The discovery of a well-marginated, rounded mass in the distal aspect of the tail of the pancreas with signal intensity features of the spleen on all precontrast and postgadolinium sequences suggests the diagnosis of IPAS. However, SPIO-enhanced MRI can be used to characterize the lesion and to establish the definite diagnosis of IPAS in case of clinical doubt.

Pancreatico-colonic fistula after acute necrotizing pancreatitis. Diagnosis with spiral CT using rectal water soluble contrast media

CONTEXT

Colonic complications are rare but lethal events in acute pancreatitis.

CASE REPORT

We report the case of a 42-year-old man who suffered from a pancreatico-colonic fistula following a necrosectomy for severe pancreatitis; the fistula was demonstrated by spiral computed tomography using rectal water soluble contrast media.

CONCLUSION

Computed tomography with rectal contrast detects pancreatico-colonic fistulas.

Focal pancreatic mass: distinction of pancreatic cancer from chronic pancreatitis using gadolinium-enhanced 3D-gradient-echo MRI

PURPOSE

To determine the accuracy of MRI including T1-weighted gadolinium (Gd)-enhanced three-dimensional-gradient-echo (3D-GE) sequences to distinguish pancreatic cancer from chronic pancreatitis in patients with pancreatic mass or focal enlargement.

MATERIALS AND METHODS

The study included 22 patients (15 males and seven females; mean age +/- SD, 56.2 +/- 11.5 years) with pancreatic mass or focal enlargement. Fourteen had pancreatic carcinoma and eight had chronic pancreatitis based on the histopathological and clinical findings. MRI examinations of all patients were retrospectively evaluated by two independent reviewers for the predetermined imaging findings of carcinoma and chronic pancreatitis. The accuracy of MRI for differentiating pancreatic carcinoma from chronic pancreatitis was determined. MRI findings of both entities were compared using t-tests, chi-squared tests, and logistic regression analyses for the differentiation of these two entities. The extent of agreement between two reviewers was determined with Kappa statistics.

RESULTS

The sensitivity and specificity of MRI including T1-weighted 3D-GE sequences for differentiating pancreatic carcinoma from chronic pancreatitis were 93% (13/14) and 75% (6/8), respectively. The most discriminative finding for pancreatic carcinoma was relative demarcation of the mass compared to background pancreas in contrast to chronic pancreatitis on post-Gd 3D-GRE sequences (P < 0.05).

CONCLUSION

MRI including Gd-enhanced T1-weighted 3D-GE sequences can differentiate pancreatic carcinoma from chronic pancreatitis successfully in most cases.

Magnetic resonance imaging of the liver: a review

In this review article, the authors discuss the essential aspects of liver magnetic resonance imaging (MRI), including protocol, intravenous contrast use and disease entities. At present, liver MRI uses fast scanning techniques, allowing the maximization of the principles of image quality, reproducibility of image quality and good conspicuity of disease. MRI is the most accurate imaging modality for the detection and characterization of diffuse and focal liver disease. In the expert opinion section, the authors refer to the advantages and challenges of 3.0T liver imaging.

Acute cholecystitis: MR findings and differentiation from chronic cholecystitis

PURPOSE

To retrospectively determine the sensitivity and specificity of magnetic resonance (MR) imaging for differentiation between acute and chronic cholecystitis, with histopathologic analysis as the reference standard.

MATERIALS AND METHODS

Institutional review board approval with waived informed consent was obtained for this HIPAA-compliant study. Four reviewers blinded to the cholecystitis type but aware that cholecystitis was present retrospectively evaluated MR images for predetermined findings in 32 patients (15 male, 17 female; mean age +/- standard deviation, 55 years +/- 20) with histopathologically proved acute or chronic cholecystitis. The final MR diagnoses and MR findings in both groups were compared with each other and with the histopathologic diagnoses to determine the sensitivity and specificity of MR imaging. Chi(2) tests were used to detect differences in MR findings between the acute and chronic cholecystitis groups.

RESULTS

MR imaging sensitivity and specificity for detection of acute cholecystitis were 95% (18 of 19 patients) and 69% (nine of 13 patients), respectively. The sensitivities of increased gallbladder wall enhancement and increased transient pericholecystic hepatic enhancement were 74% (14 of 19 patients) and 62% (10 of 16 patients), respectively. Both findings had 92% (12 of 13 patients) specificity. Sensitivities of increased wall thickness, pericholecystic fluid, and adjacent fat signal intensity changes were 100% (19 of 19 patients), 95% (18 of 19 patients), and 95% (18 of 19 patients), respectively; specificities were 54% (seven of 13 patients), 38% (five of 13 patients), and 54% (seven of 13 patients), respectively. Pericholecystic abscess, intraluminal membranes, and wall irregularity or defect each had 100% (13 of 13 patients) specificity; sensitivities were 11% (two of 19 patients), 26% (five of 19 patients), and 21% (four of 19 patients), respectively. Increased gallbladder wall enhancement (P<.001) and increased transient pericholecystic hepatic enhancement (P=.003) were the most significantly different between acute and chronic cholecystitis.

CONCLUSION

Increased gallbladder wall enhancement and increased transient pericholecystic hepatic enhancement had the highest combination of sensitivity and specificity for the diagnosis and differentiation of acute and chronic cholecystitis.

Liver MR Imaging: 1.5T versus 3T

This article focuses on technical challenges in transferring 1.5T liver protocols to 3T systems and the overall comparison of MR sequences, highlighting the advantages and disadvantages of imaging at the higher field strength. An important benefit is the capacity of acquiring high-quality, thin-section postgadolinium T1-weighted three-dimensional gradientecho sequences, most clinically relevant for the detection and characterization of small hypervascular malignant diseases. Further research and development is necessary to overcome disadvantages, such as with in- and out-of phase T1-weighted gradient-echo sequences, and to minimize artifacts that appear at 3T.