Ali Shirkhoda - Academia.edu (original) (raw)

Papers by Ali Shirkhoda

Insights into Imaging

Diagnosis of intestinal vasculitis is often challenging due to the non-specific clinical and imag... more Diagnosis of intestinal vasculitis is often challenging due to the non-specific clinical and imaging findings. Vasculitides with gastrointestinal (GI) manifestations are rare, but their diagnosis holds immense significance as late or missed recognition can result in high mortality rates. Given the resemblance of radiologic findings with some other entities, GI vasculitis is often overlooked on small bowel studies done using computed tomography/magnetic resonance enterography (CTE/MRE). Hereon, we reviewed radiologic findings of vasculitis with gastrointestinal involvement on CTE and MRE. The variety of findings on MRE/CTE depend upon the size of the involved vessels. Signs of intestinal ischemia, e.g., mural thickening, submucosal edema, mural hyperenhancement, and restricted diffusion on diffusion-weighted imaging, are common in intestinal vasculitis. Involvement of the abdominal aorta and the major visceral arteries is presented as concentric mural thickening, transmural calcifica...

Journal of the Canadian Association of Radiologists, 1985

The computed tomographic (CT) findings in eight patients with splenic infarction are described an... more The computed tomographic (CT) findings in eight patients with splenic infarction are described and correlated with ultrasound (US) in three. The diagnosis was proven in four by splenectomy or autopsy, in three by comparison with CT, having been obtained shortly before infarction, and in two by angiography. In four patients the infarct occurred as a result of hepatic or splenic artery embolization. The CT features of infarction may be difficult to differentiate from those due to trauma, inflammation or tumor, and include either a diffuse, a well circumscribed or an irregularly marginated area of low density within the spleen. Classical wedge-shaped defects are occasionally seen in the periphery of spleen. The ultrasonographic feature is usually that of a hypoechoic or an anechoic area in the spleen. In one patient, it became necessary to perform an ultrasound guided aspiration biopsy to rule out splenic abscess.

Current Problems in Diagnostic Radiology, 2004

Malignant primary and metastatic lesions of the liver have a myriad of imaging appearances. Discr... more Malignant primary and metastatic lesions of the liver have a myriad of imaging appearances. Discriminating between the various lesions requires an understanding of the underlying pathophysiology and imaging characteristics that lead to their malignant appearances. A pattern approach of recognition by imaging with understanding of why particular lesions behave the way they do on sonography, CT, MRI, and nuclear scintigraphy can be developed. A broad selection of malignant cystic liver lesions will be displayed in a multimodality pictorial style including hepatocellular carcinoma, cholangiocarcinoma, cystic and necrotic hepatic metastases, biliary cystadenoma/cystadenocarcinoma, epitheloid hemangioendothelioma, hepatoblastoma, and cystic sarcomas. Characteristic imaging features, clinical symptoms, and prognosis will be discussed. Emphasis will be placed on consistent features of these malignant lesions that help to discriminate them from other hepatic disorders.

Lower Genitourinary Radiology, 1998

RadioGraphics, 1989

Neuroblastoma is a common tumor in childhood. It arises in the adrenal gland or in various extraa... more Neuroblastoma is a common tumor in childhood. It arises in the adrenal gland or in various extraadrenal primary sites of the sympathetic chain. Clinically, it may present as an abdominal mass or as disseminated metastatic disease. We studied 52 patients with neuroblastoma, and the typical and unusual radiographic features of the disease are presented.

Journal of Computer Assisted Tomography, 1984

American Journal of Roentgenology, 1987

Parosteal osteosarcoma, a distinct entity in which the neoplasm arises on the bone surface, prese... more Parosteal osteosarcoma, a distinct entity in which the neoplasm arises on the bone surface, presents characteristic features. Thorough radiologic and histologic evaluation and early definitive surgery usually result in a favorable prognosis and make limb salvage feasible in many adult patients. Twenty-six patients with proven parosteal osteosarcoma were seen at The University of Texas M. D. Anderson Hospital and Tumor Institute at Houston.

American Journal of Roentgenology, 2003

Critical reviews in diagnostic imaging, 1997

Magnetic resonance cholangiopancreatography (MRCP) is an evolving new technique for noninvasive i... more Magnetic resonance cholangiopancreatography (MRCP) is an evolving new technique for noninvasive imaging of diseases of the biliary tree and pancreatic duct. The advantage of this method is that one can obtain maximum intensity projection (MIP) images of the pancreatico-biliary system similar to those obtained with endoscopic retrograde cholangiopancreatography (ERCP) without the need of administration of intravenous or oral contrast. Heavily T2-weighted sequences are used that render the bile and the intraductal pancreatic fluid bright against a dark background.

Journal of computer assisted tomography

The lymphatic and vascular network of the perirenal space is described. Eighteen cases of periren... more The lymphatic and vascular network of the perirenal space is described. Eighteen cases of perirenal metastases are reviewed and examples of common pitfalls are illustrated. The pathways for metastases to the perirenal areas and explanation for other abnormalities are postulated.

LEARNING OBJECTIVES To describe physical principles of various pulse sequences and their clinical... more LEARNING OBJECTIVES To describe physical principles of various pulse sequences and their clinical applications in the evaluation and diagnosis of abdominal and pelvic pathology. ABSTRACT In this exhibit the basic principles of a variety of magnetic resonance pulse sequences are briefly described. These include fast-spin-echo technique, inversion-recovery technique, fat-saturation technique, in-phase/opposed-phase sensitive technique, three-dimensional gradient-recalled-symmetric-echo (VIBE) technique etc. Under each category, various cases will be illustrated in order to emphasize the clinical application of the particular pulse sequence in a variety of pathologic conditions.

Diseases of the Abdomen and Pelvis 2010–2013, 2010

Basic knowledge of the normal intra-abdominal anatomy and of the anatomical variants is essential... more Basic knowledge of the normal intra-abdominal anatomy and of the anatomical variants is essential to understanding the spread of pathology within the peritoneum. Of special importance are constant landmarks, i.e., the anatomical relationships maintained and bounded by peritoneal and fascial attachments as well as by the abdominal adipose tissue. The peritoneal and extraperitoneal spaces and their fascial planes create complex three-dimensional structures with unique radiological characteristics. Intraperitoneal and extraperitoneal adipose tissue provides contrast interfaces between the organs and visceral structures. The intra-abdominal adipose also yields clues as to the spread and localization of many pathological conditions.

Radiology, 2012

Organized by site for easy reference, the book covers CT, MRI, ultrasound, and nuclear medicine. ... more Organized by site for easy reference, the book covers CT, MRI, ultrasound, and nuclear medicine. This edition includes advanced technologies such as multidetector CT scanning for cardiovascular imaging, CT and MR enterography for enterocolitis, virtual colonoscopy, CT and MR urography, prostate and breast MR imaging, and PET/CT scanning. Well-respected radiologists walk the reader through specific body areas, describing problems, solutions, and relevant anatomy. Users will come away with a clear understanding that will yield on-target assessments for every patient.

American Journal of Roentgenology, 2000

Section I: Variants of Normal Anatomy and Diagnostic Pitfalls in Imaging of the Thorax and Breast... more Section I: Variants of Normal Anatomy and Diagnostic Pitfalls in Imaging of the Thorax and Breast. Section II: Variants of Normal Anatomy and Diagnostic Pitfalls in Imaging of the Abdomen and Pelvis. Section III: Variants of Normal Anatomy and Diagnostic Pitfalls in Imaging of the Musculoskeletal System. Inde

American Journal of Roentgenology, 1995

Contrast-enhanced three-dimensional MR angiography has evolved into a promising technique in the ... more Contrast-enhanced three-dimensional MR angiography has evolved into a promising technique in the study of the pulmonary vasculature. Both congenital and acquired entities can be now morphologically demonstrated in a non-invasive manner obviating the need for conventional pulmonary angiography. Due to spatial resolution limitations, however, it is still premature to routinely apply the method in the detection of small subsegmental emboli, in cases of suspected pulmonary embolism, and further technical developments will be required. In this paper we present a spectrum of congenital and acquired disorders affecting the pulmonary vascular tree as demonstrated with contrast-enhanced three-dimensional MR angiography.