Dynamic Gadolinium-enhanced MR Imaging Research Articles

Optimization of Quantitative Dynamic Postgadolinium MRI Technique Using Normalized Ratios for the Evaluation of Temporomandibular Joint Synovitis in Patients with Juvenile Idiopathic Arthritis.

MR imaging has been shown to be useful in the diagnosis of juvenile idiopathic arthritis of the temporomandibular joint. Prior MR imaging approaches have relied mainly on the subjective interpretation of synovial enhancement as a marker for synovial inflammation. Although, more recently, several attempts have been made to quantify synovial enhancement, these methods have not taken into account the dynamic enhancement characteristics of the temporomandibular joint and the effect of sampling time. Our aim was to develop a clinically feasible, reproducible, dynamic, contrast-enhanced MR imaging technique for the quantitative assessment of temporomandibular joint synovitis in patients with juvenile idiopathic arthritis and to study the effect of sampling time on the evaluation of synovitis. This was a retrospective study of all patients who had dynamic, contrast-enhanced coronal T1 3T MR imaging through the temporomandibular joint at our institution between January 1, 2015, and July 8, 2016. Patients in this cohort included those with a history of juvenile idiopathic arthritis and control patients who underwent MR imaging for other routine, clinical purposes. Synovial enhancement was calculated for each temporomandibular joint using 3 different types of equations termed normalization ratios. The enhancement profiles generated by each equation were studied to determine which provided the best discrimination between affected and unaffected joints, was the least susceptible to sampling errors, and was the most clinically feasible. A ratio of synovial enhancement (defined as the difference between the postgadolinium and the pregadolinium T1 signal of the synovium) to the postgadolinium signal of the longus capitis provided the best discrimination between affected and unaffected joints, the least susceptibility to sampling error, and was thought to be the most clinically feasible method of quantification of synovial inflammation. Additional synovial enhancement ratios studied did not provide the same level rates of discrimination between the affected and unaffected joints and were thought to be too temporally variable to provide reliable clinical use. We provide a robust, reproducible, dynamic gadolinium-enhanced MR imaging technique for the quantitative assessment of temporomandibular joint synovitis in patients with juvenile idiopathic arthritis.

Prevalence of hepatic lesion types defined by T2-weighted and dynamic gadolinium-enhanced MR imaging in patients with metastasized neuroendocrine tumors.

Identifying liver metastases from neuroendocrine tumors (NETs) is a pretherapeutic challenge in patients who are candidates for liver resection. The aims of our study are to characterize and determine the frequency of different MRI characteristics of liver metastases caused by NETs in a lesion-by-lesion analysis and to determine the frequency of monomorphous and polymorphous metastases in a patient-by-patient analysis. This retrospective study involved 47 patients with liver metastases arising from histologically confirmed NETs. In a lesion-by-lesion analysis, we classified these metastases according to their MRI characteristics as follows: hypervascular lesions with homogeneous or peripheral enhancement, hypovascular lesions, pure cystic lesions, and mixed solid/cystic lesions. In the patient-by-patient analysis, we distinguished patients whose metastases had the same MRI characteristics from patients with mixed lesion characteristics. A total of 376 metastases were analyzed. Of these, 84.3% (n=317) were hypervascular, with 51.9% showing homogeneous enhancement and 32.4% (n=122) showing peripheral enhancement. Another 7.4% (n=28) were hypovascular, 5.3% (n=20) were pure cystic, and 2.9% (n=11) were mixed solid/cystic. After excluding three patients with solitary lesions, 40.9% of patients (n=18) had mixed-type lesions, consisting of hypervascular lesions with either homogeneous or peripheral enhancement in 27.3% of cases (n=12), while 59.1% of patients (n=26) had identical lesions. Approximately 15% of metastases have atypical MRI characteristics and are either hypovascular or cystic. Metastases with different MRI characteristics coexist in 40% of patients.

Hepatocellular Carcinoma in Budd-Chiari Syndrome: Enhancement Patterns at Dynamic Gadolinium-Enhanced T1-Weighted MR Imaging

The objective of this study was to analyze the enhancement patterns at dynamic gadolinium-enhanced T1-weighted MR imaging in patients of Hepatocellular Carcinoma (HCC) with associated Budd-Chiari syndrome (BCS). The MR imaging findings in 10 patients of HCC with associated BCS were compared to those of 32 other patients of HCC without BCS. During the arterial phase, significantly more lesions with BCS were hyperintense than lesions without BCS; during the equilibrium phase, significantly more lesions with BCS were slightly hyperintense or isointense than lesions without BCS (P < 0.05 for both). For HCC, contrast enhancement on MRI shows different enhancement patterns between patients of HCC with associated BCS and those without BCS.

Diagnostic value of gadolinium-enhanced dynamic MR imaging for parotid gland tumors

ObjectiveThis study aimed to evaluate the value of gadolinium-enhanced dynamic MR imaging for differentiating benign and malignant parotid gland tumors, and for characterizing the various histological types. Patients and methodsNon-enhanced T1-weighted (T1-W), fat-suppressed T2-weighted (T2-W), and gadolinium-enhanced fat-suppressed dynamic T1-weighted images were obtained preoperatively in 27 patients (28 parotid gland tumors), by using a 1.5 or 3 T MR imaging unit (GE, Signa Exite). The tumor margins and the enhancement curve patterns on dynamic MR imaging were analyzed. All patients underwent a parotidectomy with histopathologic analysis. ResultsPleomorphic adenomas depict a gradual enhancement pattern. Warthin’s tumors depict an early peak of enhancement and a high washout pattern. Malignant tumors depict an early peak of enhancement and a low washout pattern. ConclusionGadolinium-enhanced dynamic MR imaging improved the performance of MR imaging in differentiating benign from malignant parotid gland tumors and characterizing the different histological types of benign tumors.

Focal Laser Ablation of Prostate Cancer: Numerical Simulation of Temperature and Damage Distribution

BackgroundThe use of minimally invasive ablative techniques in the management of patients with low grade and localized prostate tumours could represent a treatment option between active surveillance and radical therapy. Focal laser ablation (FLA) could be one of these treatment modalities. Dosimetry planning and conformation of the treated area to the tumor remain major issues, especially when, several fibers are required. An effective method to perform pre-treatment planning of this therapy is computer simulation. In this study we present an in vivo validation of a mathematical model.MethodsThe simulation model is based on finite elements method (FEM) to solve the bio-heat and the thermal damage equations. Laser irradiation was performed with a 980 nm laser diode system (5 W, 75 s). Light was transmitted using a cylindrical diffusing fiber inserted inside a preclinical animal prostate cancer model induced in Copenhagen rats. Non-enhanced T2-weighted and dynamic gadolinium-enhanced T1-weighted MR imaging examinations were performed at baseline and 48 hours after the procedure. The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C.ResultsThe mean volume of the tissue necrosis, estimated from the histological analyses was 0.974 ± 0.059 cc and 0.98 ± 0.052 cc on the 48 h MR images. For the simulation model, volumes were: 1.38 cc when T = 43° C, 1.1 cc for T = 45°C and 0.99 cc when T = 50 C°.ConclusionsIn this study, a clear correlation was established between simulation and in vivo experiments of FLA for prostate cancer.Simulation is a promising planning technique for this therapy. It needs further more evaluation to allow to FLA to become a widely applied surgical method.

Bone metastases: Evaluation of acuity of lesions using dynamic gadolinium‐chelate enhancement, preliminary results

To evaluate whether enhancement on serial dynamic gadolinium-enhanced abdominal-pelvic MR imaging (DCE-MRI) can determine the acuity of bone metastases. Twenty consecutive patients who underwent abdominal-pelvic DCE-MRI for evaluation/staging of a proven cancer and had bone metastases were included. Two radiologists analyzed in consensus 59 DCE-MRIs of these patients. Region of interest measurements were performed in up to three lesions on noncontrast T1-weighted, serial hepatic arterial dominant phase (HADP), early hepatic venous phase (EHVF), and interstitial phase (IP) postgadolinium images, and the percentage enhancement of 134 lesions was calculated. The coordinator separately and retrospectively sorted the lesions into three groups based on the imaging and clinical information: acute/active, subacute, and chronic metastases. The mean percentage enhancement of the bone metastases classified as acute/active, subacute, and chronic in the HADP, EHVP and IP were respectively (%): 134, 107, 99; 87, 86, 87; and 39, 65, 73. In the HADP, acute/active lesions enhanced significantly more than both subacute (1.53-fold) and chronic (3.4-fold) lesions (P < 0.01). Time intensity curves were significantly different between these three entities as well. The enhancement on arterial phase images and the time-intensity curves were different for acute/active, subacute, and chronic bone metastases.

Dynamic Contrast Enhanced Magnetic Resonance Imaging of Diffuse Spinal Bone Marrow Infiltration in Patients with Hematological Malignancies

ObjectiveTo investigate the significance of the dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) parameters of diffuse spinal bone marrow infiltration in patients with hematological malignancies.Materials and MethodsDynamic gadolinium-enhanced MR imaging of the lumbar spine was performed in 26 patients with histologically proven diffuse bone marrow infiltration, including multiple myeloma (n = 6), acute lymphoblastic leukemia (n = 6), acute myeloid leukemia (n = 5), chronic myeloid leukemia (n = 7), and non-Hodgkin lymphoma (n = 2). Twenty subjects whose spinal MRI was normal, made up the control group. Peak enhancement percentage (Emax), enhancement slope (ES), and time to peak (TTP) were determined from a time-intensity curve (TIC) of lumbar vertebral bone marrow. A comparison between baseline and follow-up MR images and its histological correlation were evaluated in 10 patients. The infiltration grade of hematopoietic marrow with plasma cells was evaluated by a histological assessment of bone marrow.ResultsDifferences in Emax, ES, and TTP values between the control group and the patients with diffuse bone marrow infiltration were significant (t = -11.51, -9.81 and 3.91, respectively, p < 0.01). Emax, ES, and TTP values were significantly different between bone marrow infiltration groups Grade 1 and Grade 2 (Z = -2.72, -2.24 and -2.89 respectively, p < 0.05). Emax, ES and TTP values were not significantly different between bone marrow infiltration groups Grade 2 and Grade 3 (Z = -1.57, -1.82 and -1.58 respectively, p > 0.05). A positive correlation was found between Emax, ES values and the histological grade of bone marrow infiltration (r = 0.86 and 0.84 respectively, p < 0.01). A negative correlation was found between the TTP values and bone marrow infiltration histological grade (r = -0.54, p < 0.01). A decrease in the Emax and ES values was observed with increased TTP values after treatment in all of the 10 patients who responded to treatment (t = -7.92, -4.55, and 5.12, respectively, p < 0.01).ConclusionDCE-MRI of spine can be a useful tool in detecting diffuse marrow infiltration of hematological malignancies, while its parameters including Emax, ES, and TTP can reflect the malignancies' histological grade.

Small hypervascular hepatocellular carcinomas: value of “washout” on gadolinium-enhanced dynamic MR imaging compared to superparamagnetic iron oxide-enhanced imaging

The aim of this study was to retrospectively compare the value of "washout" on dynamic MR imaging with superparamagnetic iron oxide (SPIO)-enhanced imaging features of small hepatocellular carcinoma (HCC). A total of 74 small (5-30 mm) hypervascular HCCs in 42 cirrhotic patients who underwent double contrast material-enhanced MR imaging were evaluated to determine the presence of washout in the portal or equilibrium phase of gadolinium-enhanced dynamic imaging and decreased uptake of SPIO on T2*-weighted imaging. HCCs were verified histologically (n = 13) or by serial follow-up imaging studies (n = 61). According to the size of the lesions, 27 vs. 73% (<10 mm, n = 15; P = 0.016 on McNemar test), 39 vs. 79% (10-14 mm, n = 28; P = 0.002), 50 vs. 93% (15-20 mm, n = 14; P = 0.031), and 82 vs. 100% (>20 mm, n = 17; P = 0.250) of the lesions showed washout vs. decreased SPIO accumulation respectively. The larger the lesion, the higher the prevalence of washout or decreased SPIO uptake (P = 0.004 or P = 0.036, respectively, on Mantel-Haenszel test). In many small hypervascular HCCs up to 2 cm, SPIO-enhanced MR imaging offers essential information for early diagnosis in the absence of washout on dynamic imaging.

Differentiation between benign and malignant colon tumors using fast dynamic gadolinium-enhanced MR colonography; a feasibility study

Background Colorectal cancer will present itself as a bowel obstruction in 16–23% of all cases. However, not all obstructing tumors are malignant and the differentiation between a benign and a malignant tumor can be difficult. The purpose of our study was to determine whether fast dynamic gadolinium-enhanced MR imaging combined with MR colonography could be used to differentiate a benign from a malignant obstructing colon tumor. Methods Patients with benign colon tumor stenosis, based on diverticulitis, were asked to participate in the study. The same number of patients with verified colorectal cancer was included. Both groups had to be scheduled for surgery to be included. Two blinded observers analyzed the tumors on MR by placing a region of interest in the tumor and a series of parameters were evaluated, e.g. wash-in, wash-out and time-to-peak. Results 14 patients were included. The wash-in and wash-out rates were significantly different between the benign and malignant tumors, and a clear distinction between benign and malignant disease was therefore possible by looking only at the MR data. Furthermore, MR colography evaluating the rest of the colon past the stenosis was possible with all patients. Conclusion The results showed the feasibility of using fast dynamic gadolinium-enhanced MR imaging to differentiate between benign and malignant colonic tumors. With a high intra-class correlation and significant differences found on independent segments of the tumor, the method appears to be reproducible. Furthermore, the potential is big in performing a full preoperative colon evaluation even in patients with obstructing cancer. Trial number: NCT00114829.

Osteoid osteoma in atypical locations: The added value of dynamic gadolinium-enhanced MR imaging

Purpose To compare the results of dynamic gadolinium-enhanced magnetic resonance imaging (MRI), unenhanced MRI and computed tomography (CT), in terms of nidus conspicuity and diagnostic confidence of osteoid osteoma in atypical sites. Materials and methods CT and MR (nonenhanced T1- and T2-weighted and dynamic MRI) images of 19 patients with histologically proven osteoid osteoma located in atypical sites were retrospectively reviewed. Time–enhancement curves of the nidus and the adjacent bone marrow were generated. Images from each technique were scored for nidus conspicuity by two independent radiologists. Another blinded radiologist was asked to assess final diagnosis of the bone lesion on MR and CT images, independently. Results In all cases, nidus contrast uptake started in the arterial phase and was higher compared to the surrounding bone marrow. Dynamic MRI significantly increased nidus conspicuity compared to nonenhanced MRI ( P < .0001) and CT ( P = .04). In 6/19 (31.6%) cases nidus conspicuity was higher at dynamic MRI compared to CT. Confident diagnosis of osteoid osteoma was achieved in all patients with MRI and in 10/19 (52.6%) patients with CT. Conclusion In patients with osteoid osteoma located in atypical sites, dynamic MRI increases nidus conspicuity, allowing confident diagnosis.

Intrahepatic Extramedullary Hematopoiesis Mimicking a Hypervascular Hepatic Neoplasm on Dynamic- and SPIO-Enhanced MRI

We present a rare case of a focal intrahepatic extramedullary hematopoiesis (EMH) that mimicked a hypervascular hepatic neoplasm in a 33-year-old woman with idiopathic myelofibrosis. The lesion showed homogeneous and persistent enhancement on both contrast-enhanced CT and gadolinium-enhanced dynamic MR imaging. The lesion did not demonstrate an apparent signal drop on a T2*-weighted sequence following administration of a superparamagnetic iron-oxide agent (SHU 555A). A hepatocellular adenoma was the initial radiological diagnosis. To the best of our knowledge, this is the first report of a histopathologically proven intrahepatic EMH evaluated with dynamic- and SPIO-enhanced MRI.

The Role of Dynamic Contrast-Enhanced Magnetic Resonance Imaging Parameters in Head-Neck Tumors

We evaluated dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in various head-neck masses, some of which are very rare tumors whose DCE-MRI have not been published to date. The purpose of this study was to investigate DCE-MRI in the differentiation of benign versus malignant lesions and to evaluate the DCE-MRI parameters most predictive for malignancy. Forty-one head-neck tumors including parotid gland tumors in 41 patients were examined at gadolinium-enhanced dynamic MR imaging. There were 26 malignant and 15 benign tumors. DCE-MR images were obtained between four and six minutes. Time-signal intensity curves (TICs) of the tumors on dynamic MR images were plotted, and then time of peak enhancement ( Tpeak), and enhancement ratios (ER) with different times (such as ER30, ER60, ER90, ER120, ERmax) were also calculated. Data of the benign and malignant group with head-neck masses were compared by Mann-Whitney U-test. The mean values of time to peak ( Tpeak) were found to be significantly shorter for the malignant group than the benign tumors ( P&lt;0.05). The mean enhancement rates of malignant lesions were ER30: 60.62±52.62, ER60: 105.65±56.26, ER90: 113.17±45.83, ER120: 116.59±46.75 and ERmax: 128.56±56.51 whereas the mean enhancement rate of benign lesions were ER30: 67.35±60.78, ER60: 79.79±63.33, ER90: 84.53±64.92, ER120: 88.41±67.07 and ERmax: 112.06±66.48. The mean signal intensity values of the 60th second (ER60) and 90th second (ER90) were significantly different from other values for predicting malignancy ( P&lt;.05). The parameters obtained from the time-signal intensity curve are important in differentiating benign and malignant enhancing lesions in dynamic head-neck MR imaging. DCE-MRI cannot replace standard MR imaging sequences for evaluating head-neck masses, but in addition to routine MR imaging it will improve differentiation between benign and malignant lesions.

Application of superparamagnetic iron oxide to imaging of hepatocellular carcinoma

Superparamagnetic iron oxide (SPIO) particles are as MR contrast media composed of iron oxide crystals coated with dextran or carboxydextran. These particles are sequestered by phagocytic Kupffer cells in normal reticuloendothelial system (RES), but are not retained in tumor tissue. Consequently, there are significant differences in T2/T2* relaxation between normal RES tissue and tumors, which result in increased lesion conspicuity and detectability. The introduction of SPIO has been expected to substantially increase the detectability of hepatic metastases. For focal hepatocellular lesions, it has been documented that SPIO-enhanced MR imaging exhibits slightly better diagnostic performance than dynamic helical CT in the detection of hypervascular hepatocellular carcinoma (HCC). A combination of dynamic and static MR imaging technique using T1- and T2 imaging criteria appears to provide clinically more useful patterns of enhancement. SPIO-enhanced MR imaging also provides information useful for differential diagnosis, via enhancement of RES-containing tumors. With the exploitation of rapid T2*-sensitive sequences, SPIO-enhanced dynamic MR imaging may become comparable to gadolinium-enhanced dynamic MR imaging and dynamic studies with multidetector-row CT. SPIO-enhanced MR imaging plays an important role in therapeutic decision-making for patients with HCC.

Systemic Candidiasis

HomeRadioGraphicsVol. 23, No. 5 PreviousNext AFIP ARCHIVESSystemic CandidiasisNicholas J. E. Moore, Johnsey L. Leef, III, Yijun PangNicholas J. E. Moore, Johnsey L. Leef, III, Yijun PangAuthor Affiliations1From the Departments of Radiology and Pathology, University of Vermont School of Medicine, 111 Colchester Ave, Burlington, VT 05401. Received November 13, 2002; revision requested January 15, 2003 and received February 28; accepted March 5. Address correspondence to N.J.E.M. (e-mail: [email protected]).Nicholas J. E. MooreJohnsey L. Leef, IIIYijun PangPublished Online:Sep 1 2003https://doi.org/10.1148/rg.235025162MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References 1 Lee GR, Foerster J, Lukens J, et al. eds. Wintrobe’s clinical hematology 10th ed. Baltimore, Md: Williams & Wilkins, 1999. Google Scholar2 Anttila VJ, Elonen E, Nordling S, Sivonen A, Ruutu T, Ruutu P. Hepatosplenic candidiasis in patients with acute leukemia: incidence and prognostic implications. Clin Infect Dis 1997; 24:375-380. Crossref, Medline, Google Scholar3 Rossetti F, Brawner DL, Bowden R, et al. Fungal liver infection in marrow transplant recipients: prevalence at autopsy, predisposing factors, and clinical features. Clin Infect Dis 1995; 20:801-811. Crossref, Medline, Google Scholar4 van Burik JH, Leisenring W, Myerson D, et al. The effect of prophylactic fluconazole on the clinical spectrum of fungal diseases in bone marrow transplant recipients with special attention to hepatic candidiasis: an autopsy study of 355 patients. Medicine (Baltimore) 1998; 77:246-254. Crossref, Medline, Google Scholar5 Schwartz RS, Mackintosh FR, Schrier SL, et al. Multivariate analysis of factors associated with invasive fungal disease during remission induction therapy for acute myelogenous leukemia. Cancer 1984; 53:411-419. Crossref, Medline, Google Scholar6 Kontoyiannis DP, Luna MA, Samuels BI, Bodey GP. Hepatosplenic candidiasis: a manifestation of chronic disseminated candidiasis. Infect Dis Clin North Am 2000; 14:721-739. Crossref, Medline, Google Scholar7 Sallah S, Semelka RC, Wehbie R, Sallah W, Nguyen NP, Vos P. Hepatosplenic candidiasis in patients with acute leukaemia. Br J Haematol 1999; 106:697-701. Crossref, Medline, Google Scholar8 Lamminen AE, Anttila VJ, Bondestam S, Ruutu T, Ruutu PJ. Infectious liver foci in leukemia: comparison of short-inversion-time inversion-recovery, T1-weighted spin-echo, and dynamic gadolinium-enhanced MR imaging. Radiology 1994; 191:539-543. Link, Google Scholar9 Semelka RC, Kelekis NL, Sallah S, Worawattanakul S, Ascher SM. Hepatosplenic fungal disease: diagnostic accuracy and spectrum of appearances on MR imaging. AJR Am J Roentgenol 1997; 169:1311-1316. Crossref, Medline, Google Scholar10 Sallah S, Semelka R, Kelekis N, Worawattanakul S, Sallah W. Diagnosis and monitoring response to treatment of hepatosplenic candidiasis in patients with acute leukemia using magnetic resonance imaging. Acta Haematol 1998; 100:77-81. Crossref, Medline, Google ScholarArticle HistoryPublished in print: Sept 2003 FiguresReferencesRelatedDetailsCited ByCurrent Problems in Diagnostic Radiology, Vol. 51, No. 1Abdominal Radiology, Vol. 46, No. 6Journal of the American Academy of Dermatology, Vol. 80, No. 4Seminars in Roentgenology, Vol. 52, No. 2Multimodality Imaging of Liver Infections: Differential Diagnosis and Potential PitfallsPablo Bächler, María José Baladron, Christine Menias, Ignacio Beddings, Ron Loch, Eugenio Zalaquett, Matías Vargas, Sarah Connolly, Sanjeev Bhalla, Álvaro Huete, 27 May 2016 | RadioGraphics, Vol. 36, No. 4Current Radiology Reports, Vol. 4, No. 1Clinical Imaging, Vol. 40, No. 4Seminars in Roentgenology, Vol. 50, No. 4Ultrasound Quarterly, Vol. 24, No. 4Radiología, Vol. 49, No. 6Fungal Liver Infection in Immunocompromised Patients: Depiction with Multiphasic Contrast-enhanced Helical CT1Ur Metser, , Masoom A. Haider, , Marcus Dill-Macky, , Mostafa Atri, , Gina Lockwood, , and Mark Minden, 1 April 2005 | Radiology, Vol. 235, No. 1Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 23, No. 5 Metrics Downloaded 8,670 times Altmetric Score PDF download

Differential diagnosis of adrenal masses by chemical shift and dynamic gadolinium enhanced MR imaging.

Chemical shift MRI is widely used for identifying adenomas, but it is not a perfect method. We determined whether combined dynamic MRI methods can lead to improved diagnostic accuracy. Fifty-seven adrenal masses were examined by chemical shift and dynamic MR imaging using 2 MR systems. The masses included 38 adenomas and 19 non-adenomas. In chemical shift MRI studies, the signal intensity index (SI) was calculated, and the lesions classified into 5 types in the dynamic MRI studies. Of the 38 adenomas studied, 37 had an SI greater than 0. In the dynamic MRI, 34 of 38 adenomas showed a benign pattern (type 1). If the SI for the adenomas in the chemical shift MRI was considered to be greater than 0, the positive predictive value was 0.9, and the negative predictive value was 0.94 and kappa = 0.79. If type 1 was considered to indicate adenomas in the dynamic MRI, the corresponding values were 0.94, 0.81 and kappa = 0.77 respectively. The results obtained when the 2 methods were combined were 1, 0.95 and kappa = 0.96 respectively. The chemical shift MRI was found to be useful for identifying adenomas in most cases. If the adrenal mass had a low SI (0 < SI < 5), dynamic MRI was also found to be helpful for making a differential diagnosis.

MR imaging features of solid pseudopapillary tumor of the pancreas in adult and pediatric patients.

This study was conducted to describe the MR imaging features of solid pseudopapillary tumor of the pancreas. Solid pseudopapillary tumor of the pancreas, a tumor typically seen in young women, is a large, well-defined, encapsulated lesion with heterogeneous high or low signal intensity on T1-weighted, heterogeneous high signal intensity on T2-weighted, and early peripheral heterogeneous enhancement with progressive fill-in on gadolinium-enhanced dynamic MR imaging. These features help differentiate this rare tumor from other pancreatic neoplasms.

Carcinosarcoma of the urinary bladder: dynamic contrast-enhanced MR imaging with clinical and pathologic correlation.

This article describes the MR imaging features of carcinosarcoma of the urinary bladder with clinical presentation and pathologic correlation in three adults. Carcinosarcoma of the urinary bladder is a rare and aggressive tumor that has a clinical presentation similar to that of transitional cell carcinoma of the bladder. Dynamic gadolinium-enhanced MR imaging features are discussed.

Castleman disease of the parotid gland: MR imaging findings with pathologic correlation

A case of a hyaline-vascular type of Castleman disease originating in the parotid gland in which MR-pathologic correlation was obtained was presented. T1- and T2-weighted MR images showed a well-circumscribed 6 cm mass of intermediate signal intensity with hypointense branching structures within the mass. Gadolinium-enhanced dynamic MR imaging demonstrated a marked homogeneous enhancement of the mass with a peak enhancement at 60 s after intravenous gadolinium injection, whereas the branching structures showed a delayed enhancement to the degree of the mass at equilibrium phase. MR-pathologic correlation revealed that the branching structures corresponded to thick fibrotic bundles in the mass. A homogeneously enhancing well-circumscribed parotid mass with hypointense branching structures may indicate Castleman disease.

Low-Dose Gadobenate Dimeglumine-Enhanced MRI in the Detection and Characterization of Focal Liver Lesions

Magnetic resonance imaging (MRI) of the liver with conventional nonspecific gadolinium-based contrast agents has traditionally been performed at a dose of 0.1 mmol/kg of body weight. When administered as a bolus and combined with image acquisition during the dynamic phase of contrast enhancement, these agents at this dose have been used for the characterization of focal liver lesions (FLLs) ( 1 Hamm B Thoeni RF Gould RG et al. Focal liver lesions: characterization with nonenhanced and dynamic contrast material–enhanced MR imaging. Radiology. 1994; 190: 417-423 Crossref PubMed Scopus (217) Google Scholar , 2 Semelka RC Shoenut JP Kroeker MA et al. Focal liver disease: comparison of dynamic contrast-enhanced CT and T2-weighted fat-suppressed, FLASH, and dynamic gadolinium-enhanced MR imaging at 1.5 T. Radiology. 1992; 184: 687-694 Crossref PubMed Scopus (198) Google Scholar ). Unfortunately, these agents have not always proven satisfactory for the improved detection of FLLs, especially hypovascular metastases ( 3 Peterson MS Baron RL Murakami T Hepatic malignancies: usefulness of acquisition of multiple arterial and portal venous phase images at dynamic gadolinium-enhanced MR imaging. Radiology. 1996; 201: 337-345 Crossref PubMed Scopus (146) Google Scholar , 4 Hamm B Mahfouz AE Taupitz M et al. Liver metastases: improved detection with dynamic gadolinium-enhanced MR imaging?. Radiology. 1997; 202: 677-682 Crossref PubMed Scopus (96) Google Scholar ).

Pancreatic mass due to chronic pancreatitis: correlation of CT and MR imaging features with pathologic findings.

The purpose of this study was to identify helical CT and MR imaging features of pancreatic masses (focal enlargement) due to chronic pancreatitis and their correlation with pathologic findings. When histologic fibrosis is uniformly present through the pancreas in patients with chronic pancreatitis, there is no demarcation of masses due to chronic pancreatitis. When there is a greater degree of histologic fibrosis in the masslike part of the pancreas, the mass is often demarcated from the remaining pancreas, and the enhancement pattern on two-phase helical CT and dynamic gadolinium-enhanced MR imaging mimics that of pancreatic adenocarcinoma.