Prevalence of incidental pancreatic cysts in the adult population on MR imaging.

Objectives: The reporting of incidental pancreatic cystic lesions on cross-sectional imaging studies has dramatically increased over the last few years. The prevalence of incidental pancreatic cysts in the adult population, however, is unknown. The aim of our study was to determine the prevalence of incidentally detected pancreatic cysts in the adult population undergoing abdominal magnetic resonance (MR) imaging.

MR urography versus retrograde pyelography/ureteroscopy for the exclusion of upper urinary tract malignancy.

Aim: To evaluate the diagnostic performance of magnetic resonance urography (MRU) versus retrograde pyelography and/or ureteroscopy (RPU) in the detection of upper urinary tract neoplasms.

Materials And Methods: This retrospective study included 35 patients with suspected upper urinary tract malignancy who underwent MRU and RPU within 6-months in our institution during the study period (February 2002 to January 2007). MRU and RPU reports were reviewed and results recorded.

[Nutrition aspects in obese before and after bariatric surgery].

Objective: To determine the physical-nutritional profile of obese patients submitted to bariatric surgery at the HC/UFPE.

Methods: Two-hundred-and-five patients were evaluated retrospectively during the period of 2002 through 2006. Analysis considered clinical history for diabetes type 2 (DM 2), high blood pressure (HBP) and metabolic syndrome (MS).

Lymphatic metastases from pelvic tumors: anatomic classification, characterization, and staging.

The spread of pelvic tumors to lymph nodes is an important means of tumor dissemination. Nodal metastases have important management and prognostic impact. Pelvic tumors usually metastasize first to regional lymph nodes, which are specific groups of nodes for each tumor, and are classified according to the TNM system as N-stage disease.

An unusual variant of anomalous pancreaticobiliary junction in a patient with pancreas divisum diagnosed with secretin-magnetic resonance cholangiopancreatography.

Anomalous pancreaticobiliary junction is an unusual variant of pancreaticobiliary anatomy of clinical importance because it is associated with increased risk of pancreatitis and, also, for the development of cholangiocarcinoma. We report an unusual variant of anomalous pancreaticobiliary junction, occurring in a patient with pancreas divisum, with an anomalous communication between the dorsal pancreatic and the common bile duct. The patient presented with a distal biliary stricture.

Magnetic resonance imaging of renal masses.

The increasing frequency of incidentally detected renal masses supports the need for accurate imaging characterization to avoid unnecessary surgery/interventional procedures. Furthermore, the need for accurate presurgical diagnosis of specific histologic subtypes of renal malignancies is increasingly important as advances in understanding of tumor biology direct targeted courses of therapy. Magnetic resonance imaging is uniquely suited for the evaluation of renal masses because of its ability to provide excellent soft-tissue contrast and demonstration of enhancement, as well as its multiplanar capabilities.

Electromagnetic field quantization in time-dependent linear media.

We present a quantization scheme for the electromagnetic field in time-dependent homogeneous nondispersive conducting and nonconducting linear media without sources. Using the Coulomb gauge, we demonstrate this quantization can be mapped into a damped (attenuated) time-dependent quantum harmonic oscillator. Remarkably, we find that the time dependence of the permittivity, for epsilon>0, gives rise to an attenuation of the radiation field.

Does arterial spin-labeling MR imaging-measured tumor perfusion correlate with renal cell cancer response to antiangiogenic therapy in a mouse model?

Purpose: To determine whether arterial spin-labeling (ASL) magnetic resonance (MR) imaging findings at baseline and early during antiangiogenic therapy can predict later resistance to therapy.

Materials And Methods: Protocol was approved by an institutional animal care and use committee. Caki-1, A498, and 786-0 human renal cell carcinoma (RCC) xenografts were implanted in 39 nude mice.

Magnetic resonance imaging as a biomarker in renal cell carcinoma.

The ability to noninvasively discriminate the most common types of renal cell carcinoma (RCC) based on their magnetic resonance imaging (MRI) appearances or their magnetic resonance phenotypes is achievable. Intracellular lipids, a histologic characteristic of the clear cell RCC, can be identified on chemical shift MRI. Intratumoral hemosiderin deposition, as observed histologically with papillary RCC, correlates to the low signal intensity on T2-weighted images.

Innovations and challenges in renal cancer: summary statement from the Third Cambridge Conference.

The Third Cambridge Conference on Innovations and Challenges in Renal Cancer, a symposium held in Cambridge, Massachusetts, June 27-28, 2008, and chaired by Michael B. Atkins, was convened to discuss the current state of knowledge in the field, critique new data, stimulate communication among those involved in basic and clinical research, and offer recommendations for further study. Four main topics were discussed: genetics and molecular biology of renal cell cancer, staging and prognosis, systemic therapy, and correlative science and biomarkers in stage IV disease.

Patterns of misinterpretation of adnexal masses on CT and MR in an academic radiology department.

Rationale And Objectives: The aim of this study was to assess potential quality assurance (QA) issues in the diagnosis and characterization of adnexal masses on pelvic computed tomographic (CT) and magnetic resonance (MR) imaging studies.

Materials And Methods: Images from 128 women who had oophorectomies during a 16-month period with CT and/or MR studies within 5 years of surgery (145 CT scans from 103 women and 49 MR studies from 42 women, with 17 having both MR and CT studies) were reviewed by three radiologists who assigned QA scores of 0 (no QA issue), 1 (minor issue with minimal impact on clinical care), or 2 (major issue with potential impact on clinical care). The difficulty of diagnosis was assigned a score of 0 (very difficult diagnosis to make), 1 (difficult but possible to make the diagnosis), or 2 (diagnosis should be made).

Strategies for reducing respiratory motion artifacts in renal perfusion imaging with arterial spin labeling.

Arterial spin labeling (ASL) perfusion measurements may have many applications outside the brain. In the abdomen, severe image artifacts can arise from motions between acquisitions of multiple signal averages in ASL, even with single-shot image acquisition. Background suppression and respiratory motion synchronization techniques can be used to ameliorate these artifacts.

Quality initiatives: imaging pregnant patients with suspected pulmonary embolism: what the radiologist needs to know.

Pregnancy is associated with a fivefold increase in the prevalence of venous thromboembolism, and pulmonary embolism is a leading cause of maternal death. However, the diagnosis of pulmonary embolism during pregnancy is challenging because classic clinical symptoms are often absent and physiologic changes during pregnancy can mimic pulmonary embolism. Concerns about exposure of the fetus to ionizing radiation and intravenously administered contrast material, as well as potential medicolegal issues, further complicate the diagnosis.

Renal cell carcinoma: dynamic contrast-enhanced MR imaging for differentiation of tumor subtypes--correlation with pathologic findings.

Purpose: To retrospectively evaluate whether the enhancement patterns of pathologically proved clear cell, papillary, and chromophobe renal cell carcinomas (RCCs) measured on clinical dynamic contrast agent-enhanced magnetic resonance (MR) images permit accurate diagnosis of RCC subtype.

Materials And Methods: This study was Institutional Review Board approved and HIPAA compliant; informed consent was waived. One hundred twelve patients (76 men, 36 women; age range, 25-88 years; mean age, 58.

Pregnant patients suspected of having acute appendicitis: effect of MR imaging on negative laparotomy rate and appendiceal perforation rate.

Purpose: To investigate the effect of magnetic resonance (MR) imaging on the negative laparotomy rate (NLR) and the perforation rate (PR) in pregnant patients suspected of having acute appendicitis (AA) and to assess the need for computed tomography (CT) in this setting.

Materials And Methods: The data of 148 consecutive pregnant patients (mean age, 29 years; age range, 15-42 years; mean gestational age, 20 weeks; gestational age range, 4-37 weeks) who were clinically suspected of having AA and examined with MR imaging between March 2002 and August 2007 were retrospectively analyzed in an institutional review board-approved HIPAA-compliant protocol. One hundred forty patients underwent ultrasonography (US) before MR imaging.

Preparing first-year radiology residents and assessing their readiness for on-call responsibilities: results over 5 years.

Objective: The objective of our study was to evaluate the preparedness of postgraduate year (PGY)-2 residents for independent call responsibilities and the impact of the radiology residency training program on call preparedness using an objective DICOM-based simulation module over a 5-year period.

Materials And Methods: A month-long emergency radiology lecture series, conducted over 5 consecutive years, was designed and given to radiology residents at all levels. A DICOM-based, interactive, computer-based testing module with actual emergency department cases was developed and administered at the end of the lecture series.

Dynamic half-Fourier single-shot turbo spin echo for assessment of deep venous thrombosis: initial observations.

Objective: The objective of this study was to retrospectively analyze the value of dynamic half-Fourier single-shot turbo spin echo (HASTE) imaging in patients with suspected deep venous thrombosis (DVT).

Materials And Methods: Fifty-five veins in 24 patients were interrogated using a HASTE sequence with the patients relaxed and in various degrees of Valsalva. Veins were analyzed for changes in caliber (+CAL) and signal intensity (+SI) or in their absence (-CAL and -SI, respectively) and compared with the presence of thrombus on gadolinium-enhanced magnetic resonance imaging.

Parallel imaging enhanced MR colonography using a phantom model.

Purpose: To compare various Array Spatial and Sensitivity Encoding Technique (ASSET)-enhanced T2W SSFSE (single shot fast spin echo) and T1-weighted (T1W) 3D SPGR (spoiled gradient recalled echo) sequences for polyp detection and image quality at MR colonography (MRC) in a phantom model. Limitations of MRC using standard 3D SPGR T1W imaging include the long breath-hold required to cover the entire colon within one acquisition and the relatively low spatial resolution due to the long acquisition time. Parallel imaging using ASSET-enhanced T2W SSFSE and 3D T1W SPGR imaging results in much shorter imaging times, which allows for increased spatial resolution.

Magnetic resonance imaging-measured blood flow change after antiangiogenic therapy with PTK787/ZK 222584 correlates with clinical outcome in metastatic renal cell carcinoma.

Purpose: To measure changes in tumor blood flow following treatment with PTK787/ZK 222584, a pan-vascular endothelial growth factor receptor tyrosine kinase inhibitor, and their association with clinical response in patients with metastatic renal cell carcinoma.

Experimental Design: In 10 patients with metastatic renal cell carcinoma treated with PTK787/ZK 222584, tumor blood flow was evaluated by arterial spin labeling (ASL) magnetic resonance imaging before and 1 month on treatment. Changes in blood flow after 1 month of treatment were compared with bidimensional tumor response at 4 months of treatment using the Mann-Whitney test.

Localization of the appendix at MR imaging during pregnancy: utility of the cecal tilt angle.

Purpose: To determine whether the cecal tilt angle on sagittal magnetic resonance (MR) images in pregnant patients correlates with the location of the appendix and gestational age and whether the cecal tilt angle can help predict the location of the appendix.

Materials And Methods: This HIPAA-compliant retrospective study was approved by the institutional review board. Informed consent was waived.

Low dose pedal magnetic resonance angiography at 3 tesla with time-resolved imaging of contrast kinetics: a feasibility study.

Objectives: To assess the feasibility of low-dose time-resolved imaging of contrast kinetics (TRICKS) magnetic resonance (MR) angiography of the pedal vasculature at 3.0 Tesla (T) using a head coil.

Materials And Methods: Eleven healthy volunteers were imaged using TRICKS MR angiography at 3.

MR imaging of renal masses: correlation with findings at surgery and pathologic analysis.

Magnetic resonance (MR) imaging is useful in the characterization of renal masses. The MR imaging manifestations and pathologic diagnoses of 82 renal masses were reviewed and correlated. The MR imaging appearance of clear cell type renal cell carcinoma varies depending on the presence of cystic components, hemorrhage, and necrosis.

Body MRI using IDEAL.

Objective: The intrinsic differences of water and fat protons in the MR environment allow selective interrogation of their contribution to the MR signal. Fat-suppression techniques and chemical shift imaging are routinely used in clinical body MRI. Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) is a novel imaging technique for separating fat and water.

Lower limits of detection using magnetic resonance imaging for solid components in cystic renal neoplasms.

Objectives: We determined the positive predictive value (PPV) for malignancy in complex renal cysts with focal nodular enhancement seen on magnetic resonance imaging (MRI).

Methods: A surgical database was reviewed to identify all patients having both a preoperative 3 dimensional (3D) renal MRI and a radical or partial nephrectomy from January 2000 through April 2004 at our hospital. A group of 21 patients were identified with focal nodular enhancement within cystic renal masses.