Akram Shaaban

Acquisition and reconstruction of undersampled radial data for myocardial perfusion magnetic resonance imaging

To improve myocardial perfusion magnetic resonance imaging (MRI) by reconstructing undersampled radial data with a spatiotemporal constrained reconstruction method (STCR).

In vivo human time-exposure study of orally dosed commercial silver nanoparticles.

UNLABELLED Human biodistribution, bioprocessing and possible toxicity of nanoscale silver receive increasing health assessment. We prospectively studied commercial 10- and 32-ppm nanoscale silver particle solutions in a single-blind, controlled, cross-over, intent-to-treat, design. Healthy subjects (n=60) underwent metabolic, blood counts, urinalysis, sputum induction, and chest and abdomen magnetic resonance imaging. Silver serum and urine content were determined. No clinically important changes in metabolic, hematologic, or urinalysis measures were identified. No morphological changes were detected in the lungs, heart or abdominal organs. No significant changes were noted in pulmonary reactive oxygen species or pro-inflammatory cytokine generation. In vivo oral exposure to these commercial nanoscale silver particle solutions does not prompt clinically important changes in human metabolic, hematologic, urine, physical findings or imaging morphology. Further study of increasing time exposure and dosing of silver nanoparticulate silver, and observation of additional organ systems are warranted to assert human toxicity thresholds. FROM THE CLINICAL EDITOR In this study, the effects of commercially available nanoparticles were studied in healthy volunteers, concluding no detectable toxicity with the utilized comprehensive assays and tests. As the authors rightfully state, further studies are definitely warranted. Studies like this are much needed for the more widespread application of nanomedicine.

Fallopian Tube Disease in the Nonpregnant Patient

The increasing use of imaging necessitates familiarity with a wide variety of pathologic conditions, both common and rare, that affect the fallopian tube. These conditions should be considered in the differential diagnosis for pelvic disease in the nonpregnant patient. The most common condition is pelvic inflammatory disease, which represents a spectrum ranging from salpingitis to pyosalpinx to tubo-ovarian abscess. Isolated tubal torsion is rare but is nevertheless an important diagnosis to consider in the acute setting. Hematosalpinx in a nonpregnant patient can be an indicator of tubal endometriosis; however, care should be taken to exclude tubal torsion or malignancy. Current evidence suggests that the prevalence of primary fallopian tube carcinoma (PFTC) is underestimated and that there is a relationship between PFTC and breast cancer. PFTC has characteristic imaging features that can aid in its detection and in differentiating it from other pelvic masses. Familiarity with fallopian tube disease and the imaging appearances of both the normal and abnormal fallopian tube is crucial for optimal diagnosis and management in emergent as well as ambulatory settings.

Ovarian cancer: detection and radiologic staging.

Ovarian cancer is the second most common gynecologic malignancy. It is the deadliest, largely owing to late stage at the time of diagnosis. Ultrasound is modality of choice in the evaluation of suspected adnexal masses. Magnetic resonance imaging is an excellent problem solver when an adnexal mass is indeterminate on ultrasound. Staging of ovarian cancer remains surgical, though preoperative imaging can identify inoperable patients and identify suspicious sites for intraoperative biopsy. This article reviews the use of different imaging modalities in the detection and staging of ovarian carcinoma, and discusses imaging indications, radiologic features, and the shortcomings of imaging.

CT Findings of Acute Cholecystitis and Its Complications

OBJECTIVE The purpose of this article is to describe and illustrate the CT findings of acute cholecystitis and its complications. CONCLUSION CT findings suggesting acute cholecystitis should be interpreted with caution and should probably serve as justification for further investigation with abdominal ultrasound. CT has a relatively high negative predictive value, and acute cholecystitis is unlikely in the setting of a negative CT. Complications of acute cholecystitis have a characteristic CT appearance and include necrosis, perforation, abscess formation, intraluminal hemorrhage, and wall emphysema.

Initial Experience of Assessing Esophageal Tissue Injury and Recovery Using Delayed-Enhancement MRI After Atrial Fibrillation Ablation

Background—Esophageal wall thermal injury after atrial fibrillation ablation is a potentially serious complication. However, no noninvasive modality has been used to describe and screen patients to examine whether esophageal wall injury has occurred. We describe a noninvasive method of using delayed-enhancement MRI to detect esophageal wall injury and subsequent recovery after atrial fibrillation ablation. Methods and Results—We analyzed the delayed-enhancement MRI scans of 41 patients before ablation and at 24 hours and 3 months after ablation to determine whether there was evidence of contrast enhancement in the esophagus after atrial fibrillation ablation. In patients with contrast enhancement, 3D segmentation of the esophagus was performed using a novel image processing method. Upper gastrointestinal endoscopy was then performed. Repeat delayed-enhancement MRI and upper gastrointestinal endoscopy was performed 1 week later to track changes in lesions. The wall thickness of the anterior and posterior wall of the esophagus was measured at 3 time points: before ablation, 24 hours after ablation, and 3 months after ablation. Evaluation of preablation MRI scans demonstrated no cases of esophageal enhancement. At 24 hours, 5 patients showed contrast enhancement. Three of these patients underwent upper gastrointestinal endoscopy, which demonstrated esophageal lesions. Repeat upper gastrointestinal endoscopy and MRI 1 week later demonstrated resolution of the lesions. All 5 patients had confirmed resolution of enhancement at 3 months. All patients with esophageal tissue enhancement demonstrated left atrial wall enhancement directly adjacent to the regions of anterior wall esophageal enhancement. Conclusions—Our preliminary results indicate delayed-enhancement MRI can assess the extent and follow progression of esophageal wall injury after catheter ablation of atrial fibrillation. It appears that acute esophageal injury recovers within 1 week of the procedure.

Hematologic Malignancies of the Liver: Spectrum of Disease

The incidence of hematologic malignancies and their extranodal manifestations is continuously increasing. Previously unsuspected hepatic involvement in hematologic malignancies such as Hodgkin disease and non-Hodgkin lymphoma, posttransplant lymphoproliferative disorder, myeloid sarcoma (chloroma), multiple myeloma, Castleman disease, and lymphohistiocytosis may be seen by radiologists. Although the imaging features of more common hepatic diseases such as hepatocellular carcinoma, metastases, and infection may overlap with those of hepatic hematologic malignancies, combining the imaging features with clinical manifestations and laboratory findings can facilitate correct diagnosis. Clinical features that suggest a hematologic neoplasm as the cause of liver lesions include a young patient (<40 years of age), no known history of cancer, abnormal bone marrow biopsy results, fever of unknown origin, and night sweats. Imaging features that suggest hematologic malignancy include hepatosplenomegaly or splenic lesions, vascular encasement by a tumor without occlusion or thrombosis, an infiltrating mass at the hepatic hilum with no biliary obstruction, and widespread adenopathy above and below the diaphragm. Familiarity with the imaging features of hepatic hematologic malignancies permits correct provisional diagnosis and may influence therapeutic management. For example, when biopsy is performed, core biopsy may be needed in addition to fine-needle aspiration so that the tissue architecture of the neoplasm can be discerned. The predominant treatment of hematologic malignancies is chemotherapy or radiation therapy rather than surgery. Online supplemental material is available for this article.

Ovarian Malignant Germ Cell Tumors: Cellular Classification and Clinical and Imaging Features

Ovarian malignant germ cell tumors (OMGCTs) are heterogeneous tumors that are derived from the primitive germ cells of the embryonic gonad. OMGCTs are rare, accounting for about 2.6% of all ovarian malignancies, and typically manifest in adolescence, usually with abdominal pain, a palpable mass, and elevated serum tumor marker levels, which may serve as an adjunct in the initial diagnosis, monitoring during therapy, and posttreatment surveillance. Dysgerminoma, the most common malignant germ cell tumor, usually manifests as a solid mass. Immature teratomas manifest as a solid mass with scattered foci of fat and calcifications. Yolk sac tumors usually manifest as a mixed solid and cystic mass. Capsular rupture or the bright dot sign, a result of increased vascularity and the formation of small vascular aneurysms, may be present. Embryonal carcinomas and polyembryomas rarely manifest in a pure form and are more commonly part of a mixed germ cell tumor. Some OMGCTs have characteristic features that allow a diagnosis to be confidently made, whereas others have nonspecific features, which make them difficult to diagnose. However, imaging features, the patients age at presentation, and tumor markers may help establish a reasonable differential diagnosis. Malignant ovarian germ cell tumors spread in the same manner as epithelial ovarian neoplasms but are more likely to involve regional lymph nodes. Preoperative imaging may depict local extension, peritoneal disease, and distant metastases. Suspicious areas may be sampled during surgery. Because OMGCTs are almost always unilateral and are chemosensitive, fertility-sparing surgery is the standard of care.

The radiological spectrum of small-airway diseases.

The small airways of the lungs are an often misunderstood and confusing anatomic location teeming with an array of similar-appearing disease processes that can be daunting even to the most experienced radiologist. This article shows that an understanding of small-airway anatomy and accurate pattern recognition can allow one to determine useful clinical differential diagnoses. The ability to recognize mosaic lung attenuation, and the presence of centrilobular nodules and reticular opacities (tree-in-bud), with or without ground glass, is of critical importance in evaluating this portion of the lung. In addition, we attempt to further show how high-resolution computed tomography (HRCT) scanning has opened the deep recesses of the lung to the thoracic radiologist, allowing for a more meaningful radiologic contribution to the clinical care of patients with unexplained pulmonary symptomatology.

Clinical evaluation, imaging studies, indications for cytologic study, and preprocedural requirements for duct brushing studies and pancreatic FNA: The papanicolaou society of cytopathology recommendations for pancreatic and biliary cytology

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pancreaticobiliary cytology including indications for endoscopic ultrasound (EUS) and fine‐needle aspiration (FNA) biopsy, techniques for EUS‐FNA, terminology and nomenclature to be used for pancreaticobiliary disease, ancillary testing, and post‐biopsy management. All documents are based on expertise of the authors, literature review, discussions of the draft document at national and international meetings, and synthesis of online comments of the draft document. This document selectively presents the results of these discussions.