Siddharth P. Jadhav

SEMAC-VAT and MSVAT-SPACE sequence strategies for metal artifact reduction in 1.5T magnetic resonance imaging.

Objectives:To evaluate the ability of four magnetic resonance imaging (MRI) techniques to correct for metallic artifacts. These techniques consisted of 3 2D techniques and one 3D technique. In 2D imaging the techniques View Angle Tilting (VAT), Slice Encoding for Metal Artifact Correction (SEMAC) and a technique that employed a combination of the first two (SEMAC-VAT) were evaluated. In 3D imaging the technique Multiple Slab acquisition with VAT based on a SPACE sequence was evaluated (MSVAT-SPACE). Materials and Methods:Agarose phantoms and tissue phantoms with two commonly used metal implants (stainless steel and titanium) as well as two volunteers with metal implants were imaged at 1.5T. All phantoms and volunteers were imaged using VAT, SEMAC, SEMAC-VAT and MSVAT-SPACE techniques, as well as 2D and 3D conventional imaging techniques. Each technique was optimized for different image contrast mechanisms. Artifact reduction was quantitatively assessed in the agarose phantoms by volumetric measurement. Image quality was qualitatively assessed by blinded reads employing two readers. Each reader independently viewed the tissue phantom images and in vivo human images. Statistical analysis was performed using a Friedman test, Wilcoxon test and weighted Cohens kappa test. Results:T1-weighted, T2-weighted, PD-weighted and STIR image contrasts were successfully implemented with the evaluated artifact reduction sequences in both the phantom experiments and in vivo images. For all evaluated image contrasts and both metal implants, a reduction in the volume of metal artifacts was seen when compared with 2D conventional acquisitions. The 2D metal artifact volumes on average were reduced by 49% ± 16%, 56% ± 15% and 63% ± 15% for VAT, SEMAC and SEMAC-VAT acquisitions respectively. When Friedman and Wilcoxon tests were applied the difference in metal artifact volume was found to be statistically significant when VAT, SEMAC and SEMAC-VAT were compared with the 2D conventional techniques. In 3D imaging on average MSVAT-SPACE reduced metal artifact volume compared with the 3D conventional imaging technique by 72% ± 23% for all evaluated image contrasts and both metal implants. The metal artifact volume differences were statistically significant when MSVAT-SPACE was compared with the 3D conventional technique. The blinded reads demonstrated that SEMAC-VAT and MSVAT-SPACE had distinctly superior quality compared with conventional acquisitions. Quality was measured in terms of artifact size, distortions, image quality and visualization of bone marrow and soft tissues adjacent to metal implants. This was the case for both tissue phantom images and human images with good interobserver agreement. Conclusions:SEMAC-VAT (2D) and MSVAT-SPACE (3D) demonstrated a consistent, marked reduction of metal artifacts for different metal implants and offered flexible image contrasts (T1, T2, PD and STIR) with high image quality. These techniques likely will improve the evaluation of postoperative patients with metal implants.

Morel-Lavallee seroma: a review of two cases in the lumbar region in the adolescent.

Morel-Lavallee seroma (MLS) is a lesion that develops after blunt closed soft tissue trauma and after surgical procedures particularly in the pelvis and abdomen. We describe two cases of MLS occurring in the lumbar spinal region in adolescent males who sustained blunt pelvic and abdominal trauma. Imaging plays a key role in the diagnosis of the MLS lesion and is essential in differentiating delayed MLS from lesions such as abscess, posttraumatic meningocele, and more sinister entities such as soft tissue sarcomas. MLS in the lumbar spinal region in adolescents has not been previously reported in the literature, and our aim is to describe the imaging characteristics of these lesions. Case reports

Commonly missed subtle skeletal injuries in children: a pictorial review

Children are distinctive as compared to adults when it comes to musculoskeletal injuries. This is due to the relative elasticity of bones and the presence of epiphyseal plates. There are many subtle injuries which will be missed if the radiologist is not aware of them and is not actively searching for them. The common elusive injuries include: (1) plastic bending fractures, (2) sternoclavicular dislocation, (3) epiphyseal–metaphyseal injuries in older child, (4) buckle fractures, and (5) Toddler fracture types I and II. Detection of these injuries needs an accurate history, a good physical examination, and, in particular, a thorough search by the radiologist. In many cases, it is the radiologist who suggests likelihood of the injury and guides management. In this respect, the use of comparative views and, in some cases, additional imaging is warranted. Here, we review the elusive musculoskeletal injuries in children in pictorial form.

Emergency musculoskeletal imaging in children

Emergency musculoskeletal imaging in children / , Emergency musculoskeletal imaging in children / , کتابخانه دیجیتال جندی شاپور اهواز

Mediastinal Chest Masses in Children: Part II

In children, as in adults, mediastinal chest masses are classified based on their location in the mediastinum: i.e., anterior, middle, or posterior. Most of these masses are first detected on plain chest films but then are investigated with CT, MR, and, occasionally, nuclear scintigraphy. Nuclear scintigraphy is used primarily for lesions suspected of being thyroid in origin or gastroenteric cysts containing gastric mucosa. Usually, plain chest films provide basic information regarding the location of the mass, with subsequent information derived from CT, MR, and ultrasound imaging. This article (the first part of a two-part series) deals with anterior mediastinal chest masses in children. Middle and posterior mediastinal chest masses in children will be discussed as the second part of the series in Volume 33, Number 14.