Adnan Sheikh

Uncommon Primary Pelvic Retroperitoneal Masses in Adults: A Pattern-based Imaging Approach

There is a broad spectrum of primary pelvic retroperitoneal masses in adults that demonstrate characteristic epidemiologic and histopathologic features and natural histories. These masses may be classified into five distinct subgroups using a pattern-based approach that takes anatomic distribution and certain imaging characteristics into account, allowing greater accuracy in their detection and characterization and helping to optimize patient management. The five groups are cystic (serous and mucinous epithelial neoplasms, pelvic lymphangioma, tailgut cyst, ancient schwannoma), vascular or hypervascular (solitary fibrous tumor, paraganglioma, pelvic arteriovenous malformation, Klippel-Trénaunay-Weber syndrome, extraintestinal GIST [gastrointestinal stromal tumor]), fat-containing (lipoma, liposarcoma, myelolipoma, presacral teratoma), calcified (calcified lymphocele, calcified rejected transplant kidney, rare sarcomas), and myxoid (schwannoma, plexiform neurofibroma, myxoma).Cross-sectional imaging modalities help differentiate the more common gynecologic neoplasms from more unusual masses. In particular, the tissue-specific multiplanar capability of high-resolution magnetic resonance imaging permits better tumor localization and internal characterization, thereby serving as a road map for surgery.

3D printed ventricular septal defect patch: a primer for the 2015 Radiological Society of North America (RSNA) hands-on course in 3D printing

Hand-held three dimensional models of the human anatomy and pathology, tailored-made protheses, and custom-designed implants can be derived from imaging modalities, most commonly Computed Tomography (CT). However, standard DICOM format images cannot be 3D printed; instead, additional image post-processing is required to transform the anatomy of interest into Standard Tessellation Language (STL) format is needed. This conversion, and the subsequent 3D printing of the STL file, requires a series of steps. Initial post-processing involves the segmentation-demarcation of the desired for 3D printing parts and creating of an initial STL file. Then, Computer Aided Design (CAD) software is used, particularly for wrapping, smoothing and trimming. Devices and implants that can also be 3D printed, can be designed using this software environment. The purpose of this article is to provide a tutorial on 3D Printing with the test case of complex congenital heart disease (CHD). While the infant was born with double outlet right ventricle (DORV), this hands-on guide to be featured at the 2015 annual meeting of the Radiological Society of North America Hands-on Course in 3D Printing focused on the additional finding of a ventricular septal defect (VSD). The process of segmenting the heart chambers and the great vessels will be followed by optimization of the model using CAD software. A virtual patch that accurately matches the patient’s VSD will be designed and both models will be prepared for 3D printing.

MR Imaging of Osseous Lesions of the Hip

MR imaging, because of its multiplanar capability and superior soft tissue contrast resolution, is the preferred modality to assess osseous and soft tissue structures around the hip joint. This article reviews the clinical presentation, disease process, and imaging findings of important congenital and acquired osseous disorders of the pediatric and adult hip.

Small-Bowel and Mesenteric Injuries in Blunt Trauma of the Abdomen

Bowel and mesentery are injured in an estimated 1%-5% of cases after blunt trauma [1e3] and is the third most common type of injury from blunt trauma to abdominal organs [4e7]. There are 3 basic mechanisms that govern injury to bowel and mesentery, and include direct crushing force, shearing force, and a sudden increase in intraluminal pressure that results in burst injuries [8]. Missed or delayed diagnosis is multifactorial. Symptoms may be absent on initial presentation and, when present, may be nonspecific. Furthermore, clinical assessment of some patients may not be reliable in the presence of concomitant injuries. The result of these undiagnosed injuries is increased morbidity and mortality [2,9e13]. Diagnostic tests in patients with suspected abdominal injury include peritoneal lavage, ultrasonography, and computed tomography (CT). Although sensitivity of peritoneal lavage for detection of hemoperitoneum is higher than 90% [14e16], it is neither specific nor sensitive, with undetected bowel perforation seen in up to 10% of cases [17]. Focused ultrasound assessment in trauma has a sensitivity of 86% for detection of free intra-abdominal fluid but is nonspecific with regard to organ injury [18]. In comparison, multidetector CT is more sensitive and specific than diagnostic peritoneal lavage, abdominal ultrasound, and clinical examination for the diagnosis of bowel and mesenteric injuries [19], with improved diagnostic accuracy making it the imaging modality of choice for evaluation of abdominal and pelvic trauma [20e29].

Multi-modality imaging review of congenital abnormalities of kidney and upper urinary tract

Congenital abnormalities of the kidney and urinary tract (CAKUT) include a wide range of abnormalities ranging from asymptomatic ectopic kidneys to life threatening renal agenesis (bilateral). Many of them are detected in the antenatal or immediate postnatal with a significant proportion identified in the adult population with varying degree of severity. CAKUT can be classified on embryological basis in to abnormalities in the renal parenchymal development, aberrant embryonic migration and abnormalities of the collecting system. Renal parenchymal abnormalities include multi cystic dysplastic kidneys, renal hypoplasia, number (agenesis or supernumerary), shape and cystic renal diseases. Aberrant embryonic migration encompasses abnormal location and fusion anomalies. Collecting system abnormalities include duplex kidneys and Pelvi ureteric junction obstruction. Ultrasonography (US) is typically the first imaging performed as it is easily available, non-invasive and radiation free used both antenatally and postnatally. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful to confirm the ultrasound detected abnormality, detection of complex malformations, demonstration of collecting system and vascular anatomy and more importantly for early detection of complications like renal calculi, infection and malignancies. As CAKUT are one of the leading causes of end stage renal disease, it is important for the radiologists to be familiar with the varying imaging appearances of CAKUT on US, CT and MRI, thereby helping in prompt diagnosis and optimal management.

Is a Picture Worth a Thousand Words? The Effect of Viewing Patient Photographs on Radiologist Interpretation of CT Studies

DESCRIPTION OF THE PROBLEM The past decade has seen sweeping changes to radiologic practice. Year-onyear increases in CT utilization [1,2] and the introduction of teleradiology [3] have inexorably shifted practice toward rapid reporting of cross-sectional imaging. An unintended effect of these changes has been a perceptible reduction in patient contact, with radiologists becoming increasingly remote from patient care [4,5] and feeling personally detached from patients [6]. To “personalize” the reporting process, the idea of presenting patient photographs to reporting radiologists was investigated in an unpublished study [7]. The authors suggested that radiologists produced longer reports containing more incidental findings, and subjectively reported more meticulously and empathetically, when presented with patients’ photographs. The study attracted considerable media attention and was even included in a published nonfiction book [8]. However, its significance remains unclear, because the incidental abnormalities were not classified in terms of clinical importance, and the findings have not been reproduced elsewhere. The purpose of this study was to assess whether presenting patients’

Imaging in Pre- and Post-operative Assessment in Joint Preserving and Replacing Surgery

Within the recent years, advances in imaging technology have increased its applicability to diagnose musculoskeletal disease. The modification of imaging techniques and improved image quality has led to increased use of computed tomography and magnetic resonance imaging in the assessment of postoperative complications related to orthopedic procedures. This article discusses the indications, pre- and post-operative imaging findings and post-operative complications of knee and hip arthoplasty, articular cartilage repair and high tibial osteotomy.

The use of adaptive statistical iterative reconstruction (ASiR) technique in evaluation of patients with cervical spine trauma: impact on radiation dose reduction and image quality

OBJECTIVE The aim of this study was to evaluate the impact of adaptive statistical iterative reconstruction (ASiR) technique on the image quality and radiation dose reduction. The comparison was made with the traditional filtered back projection (FBP) technique. METHODS We retrospectively reviewed 78 patients, who underwent cervical spine CT for blunt cervical trauma between 1 June 2010 and 30 November 2010. 48 patients were imaged using traditional FBP technique and the remaining 30 patients were imaged using the ASiR technique. The patient demographics, radiation dose, objective image signal and noise were recorded; while subjective noise, sharpness, diagnostic acceptability and artefacts were graded by two radiologists blinded to the techniques. RESULTS We found that the ASiR technique was able to reduce the volume CT dose index, dose-length product and effective dose by 36%, 36.5% and 36.5%, respectively, compared with the FBP technique. There was no significant difference in the image noise (p = 0.39), signal (p = 0.82) and signal-to-noise ratio (p = 0.56) between the groups. The subjective image quality was minimally better in the ASiR group but not statistically significant. There was excellent interobserver agreement on the subjective image quality and diagnostic acceptability for both groups. CONCLUSION The use of ASiR technique allowed approximately 36% radiation dose reduction in the evaluation of cervical spine without degrading the image quality. ADVANCES IN KNOWLEDGE The present study highlights that the ASiR technique is extremely helpful in reducing the patient radiation exposure while maintaining the image quality. It is highly recommended to utilize this novel technique in CT imaging of different body regions.

Non-neoplastic hepatic vascular diseases: Spectrum of CT and MRI appearances

The unique dual blood supply of the liver makes it one of the common sites for various vascular neoplastic and non-neoplastic diseases. Increasing use of multiphase contrast-enhanced computed tomography (CT) and dynamic magnetic resonance imaging (MRI) has led to increased identification of numerous non-neoplastic vascular entities apart from already well-known neoplastic lesions. The objective of this review is to describe the causes and clinical features and to familiarize the reader with the key imaging features of various non-neoplastic vascular diseases affecting the liver. Non-neoplastic vascular diseases are classified broadly as those affecting the hepatic veins, portal veins, hepatic artery, intrahepatic shunts, and other miscellaneous conditions.

Complications of minimally invasive procedures of the abdomen and pelvis: a comprehensive update on the clinical and imaging features

Minimally invasive gastrointestinal, genitourinary, and gynecological procedures are widely used in the clinical practice for diagnostic and therapeutic purposes. Complications both minor and major are not uncommon with these procedures. Imaging plays an important role in the detection and optimal management of these complications. Familiarity with the clinical and imaging features of these complications by radiologists can help in their timely detection.