Dmitry Rakita

Imaging of the Placenta with Pathologic Correlation

The placenta functions to nourish and protect the fetus. Imaging of the placenta can have a profound impact on patient management, owing to the morbidity and mortality associated with various placental conditions. To fully appreciate placental pathology, its physiology, anatomy, and variant anatomy will be outlined. Placental conditions affecting the mother and fetus include molar pregnancies, placental hematoma, abruption, previa, accreta, vasa previa, choriocarcinoma, and retained products of conception. Ultrasonography remains the definitive modality in diagnosing most of these conditions, with magnetic resonance imaging remaining an adjunctive measure. Computed tomography is occasionally used in cases of trauma and tumor staging.

Adnexal Masses in Pregnancy

Adnexal masses are often seen in the gravid patient. With current advances in technology, an increased number of adnexal masses are incidentally discovered on antenatal screening ultrasonography examinations. Sonography is the first-line imaging modality for any adnexal mass. However, further evaluation with magnetic resonance imaging (MRI) may be critical for diagnosis. For example, MRI can determine whether a mass contains fat, which can be useful in the diagnosis of a teratoma. Characteristic features of nonneoplastic and neoplastic ovarian lesions seen on sonography and MRI will be discussed. Radiologic features that help distinguish benign from malignant neoplasms will be described. Additional lesions specific to the gravid state must be considered in the differential diagnosis when appropriate, such as hyperstimulated ovaries, hyperreactio luteinalis, theca lutein cyst, and luteomas.

Renal lymphoma: MR appearance with diffusion-weighted imaging.

Abstract Imaging of renal lymphoma on magnetic resonance imaging and diffusion-weighted imaging is not well documented in the literature. We present a case of renal lymphoma in a 61-year-old patient with computed tomography and magnetic resonance imaging correlation. The lymphomatous lesions demonstrate mild enhancement and restricted diffusion. Differential considerations for hypoenhancing masses include papillary or chromophobe renal cell carcinoma, lymphoma, urothelial tumor, or metastasis, all of which have different management pathways. Apparent diffusion coefficient values can be obtained using diffusion-weighted imaging, and may be useful in identifying focal renal lesions, especially on noncontrast imaging. Apparent diffusion coefficient values may be helpful in differentiating between some of these lesions, although more investigation is needed.

Primary Liver Tumors in Pediatric Patients: Proper Imaging Technique for Diagnosis and Staging

Liver tumors in children are rare and comprise a diverse set of both benign and malignant lesions, most of which are not clinically detected until they are large and often difficult to resect. Technological advances in diagnostic imaging have greatly influenced the surgical planning of these lesions and ultimately the clinical outcome. The intent of this article is to present an imaging algorithm for the effective and efficient workup of liver tumors in pediatric patients. This includes the appropriate timing and use of various imaging modalities, such as conventional radiographs, ultrasound, computed tomography, and magnetic resonance imaging. This article also addresses the use of sedation, intravenous contrast agents, and the benefits and limitations of specific imaging modalities. An overview of the radiologic and pathologic findings in common liver lesions in pediatric patients, as well as individual case examples demonstrating the use of the proposed workup algorithm, is provided.

Diffusion-weighted MRI of renal cell carcinoma, upper tract urothelial carcinoma, and renal infection: a pictorial review

Abstract Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a functional imaging technique that derives image contrast from differences in water molecule diffusion within tissues. DW MRI helps detect and characterize renal and urothelial malignancies, may help in differentiating some benign from malignant renal masses, and can also recognize renal and upper urinary tract infections. Patients precluded from receiving intravenous contrast agents may particularly benefit from this technique.

Magnetic resonance enterography in evaluation and management of children with Crohn's disease

The role of radiologic evaluation in Crohns disease (CD) has undergone a recent paradigm shift in which the radiologist adds value to the multidisciplinary team by longitudinally assessing therapeutic response and identifying treatment-modifying subtypes, such as fibrostenotic or fistulizing disease. Magnetic resonance enterography (MRE) has become the primary imaging modality used. The combination of multiplanar, multiparametric, and multiphasic contrast-enhanced imaging with the high spatial resolution and very high tissue contrast of MR imaging allows for detailed evaluation of intra-abdominal pathology, without the risk of cumulative radiation exposure. MRE provides the benefit of a complete evaluation of mural, extramural, and even extraintestinal manifestations and complications of CD in a single examination. Cine motility sequences and diffusion-weighted imaging may further increase sensitivity and specificity. MRE represents an ideal imaging modality for initial evaluation, assessment of therapeutic response, and evaluation of complications in patients with CD.

Intravenous vs. oral hydration administration for optimal ureteral opacification in computer tomographic urography

PurposeComputed tomographic urography (CTU) is the gold standard in the radiologic detection of urinary tract disease. The goals of CTU protocols are to garner fully distended and opacified collecting systems, ureters, and bladder for adequate evaluation. Multiple techniques have been reported in the literature to optimize urinary tract visualization and enhance genitourinary assessment. However, currently no strict guidelines exist regarding the preferred method for optimal urinary tract opacification in CTU.Materials and methodsDuring the year 2013, a retrospective chart review of CTU examinations were done at either an academic institution where IV hydration was routinely administered or at an outpatient imaging center where oral hydration was preferred. Two attending radiologists experienced in cross-sectional body imaging, retrospectively reviewed all the images, blinded to the method of hydration. The reviewers were asked to quantify ureteral distension as well as to grade urinary tract opacification.ResultsA total of 176 patients and 344 ureters were analyzed. Mean maximal ureteral widths were largest in the mid ureter, followed closely by the proximal ureter. Mean opacification scores showed no statistical significance between hydration methods, stratified by ureteral segment.ConclusionOur study results show that oral hydration is easy to implement, produces ureteral distention and opacification similar to CTU studies with IV hydration, without loss of diagnostic quality in our select patient population. Although not statistically significant, the oral hydration protocol is more cost effective, requires less hospital resources, and may be a useful step toward cost-containment strategies pertinent in today’s healthcare landscape.