Nishant Gupta

Magnetic resonance imaging of bacterial and tuberculous spondylodiscitis with associated complications and non-infectious spinal pathology mimicking infections: a pictorial review

Magnetic resonance (MR) imaging plays an important role in the evaluation of bacterial and tuberculous spondylodiscitis and associated complications. Owing to its high sensitivity and specificity, it is a powerful diagnostic tool in the early diagnosis of ongoing infections, and thus provides help in prompt initiation of appropriate, therapy which may be medical or surgical, by defining the extent of involvement and detection of complications such as epidural and paraspinal abscesses. More specifically, MR imaging helps in differentiating bacterial from tuberculous infections and enables follow up of progression or resolution after appropriate treatment. However, other non-infectious pathology can demonstrate similar MR imaging appearances and one should be aware of these potential mimickers when interpreting MR images. Radiologists and other clinicians need to be aware of these potential mimics, which include such pathologies as Modic type I degenerative changes, trauma, metastatic disease and amyloidosis. In this pictorial review, we will describe and illustrate imaging findings of bacterial and tuberculous spondylodiscitis, their complications and non-infectious pathologies that mimic these spinal infections.

Role of diffusion-weighted imaging in head and neck lesions: Pictorial review

Head and neck cancers are very common worldwide, causing significant morbidity and mortality. Squamous cell carcinoma originating from the epithelial lining of the upper aerodigestive tract is the most common histology. Many patients with head and neck cancers present with advanced stage disease requiring aggressive treatment consisting of extensive surgery and chemo-radiation. Appropriate treatment planning as well as prognosis of tumors depends to a large extent on accurate histological diagnosis and differentiation of malignant from benign lesions. Routine imaging modalities such as computed tomography and magnetic resonance imaging give volumetric and morphologic information. However, these modalities cannot be reliably used as a substitute for biopsy in treatment planning. However, diffusion-weighted imaging has shown promise in tissue characterization for primary tumors and nodal metastases, differentiation of recurrent tumor from post therapeutic changes, prediction and monitoring of treatment response, and many other clinical scenarios as described later in this article. In this review article, we describe the imaging findings in applications of diffusion-weighted imaging in the head and neck lesions and discuss their added value over anatomic imaging.

Toxins in Brain! Magnetic Resonance (MR) Imaging of Toxic Leukoencephalopathy – A Pictorial Essay

Summary Toxic leukoencephalopathy results from damage to the white matter caused by various toxins. It manifests itself as white matter signal abnormalities with or without the presence of restricted diffusion. These changes are often reversible if the insulting agent is removed early, with the exception of posthypoxic leukoencephalopathy that can manifest itself 1–2 weeks after the initial insult. However, many other potential causes of white matter signal abnormalities can mimic the changes of toxic leukoencephalopathy. Thus, familiarity with the causes, clinical presentation and particularly imaging findings of toxic leukoencephalopathy is critical for early treatment and improved prognosis. The purpose of this pictorial essay is to familiarize the reader with the various causes of toxic leukoencephalopathy along with its differential diagnoses and mimics.

Usefulness of enhancement-perfusion mismatch in differentiation of CNS lymphomas from other enhancing malignant tumors of the brain

Background Surgical planning and treatment options for primary or secondary central nervous system lymphomas (PCNSL or SCNSL) are different from other enhancing malignant lesions such as glioblastoma multiforme (GBM), anaplastic gliomas and metastases; so, it is critical to distinguish them preoperatively. We hypothesized that enhancement-perfusion (E-P) mismatch on dynamic susceptibility weighted magnetic resonance (DSC-MR) perfusion imaging which corresponds to low mean relative cerebral blood volume (mean rCBV) in an enhancing portion of the tumor should allow differentiation of CNS lymphomas from other enhancing malignant lesions. Methods We retrospectively reviewed pre-treatment MRI exams, including DSC-MR perfusion images of 15 lymphoma patients. As a control group, pre-treatment DSC-MR perfusion images of biopsy proven 18 GBMs (group II), 13 metastases (group III), and 10 anaplastic enhancing gliomas (group IV) patients were also reviewed. Region of interests (ROIs) were placed around the most enhancing part of tumor on contrast-enhanced T1WI axial images and images were transferred onto co-registered DSC perfusion maps to obtain CBV in all 4 groups. The mean and maximum relative CBV values were obtained. Statistical analysis was performed on SPSS software and significance of the results between the groups was done with Mann-Whitney test, whereas optimal thresholds for tumor differentiation were done by receiver operating characteristic (ROC) analysis. Results The enhancing component of CNS lymphomas were found to have significantly lower mean rCBV compared to enhancing component of GBM (1.2 versus 4.3; P<0.001), metastasis (1.2 versus 2.7; P<0.001), and anaplastic enhancing gliomas (1.2 versus 2.4; P<0.001). Maximum rCBV of enhancing component of lymphoma were significantly lower than GBM (3.1 versus 6.5; P<0.001) and metastasis (3.1 versus 4.9; P<0.013), and not significantly lower than anaplastic enhancing gliomas (3.9 versus 4.2; P<0.08). On the basis of ROC analysis, mean rCBV provided the best threshold [area under the curve (AUC) =0.92] and had better accuracy in differentiating malignant lesions. Conclusions E-P mismatch in DSC perfusion MR, i.e., low mean rCBV in an enhancing portion of the tumor is strongly suggestive of lymphoma and should allow differentiation of CNS lymphoma from other enhancing malignant lesions.

Some Stones Are Precious—Extraluminal Appendicoliths

Appendicoliths are commonly implicated in the etiopathogenesis of acute appendicitis. Extraluminal appendicoliths are not uncommon and are frequently encountered with ruptured appendicitis. The present image scenario focuses on the importance of identifying and subsequently retrieval of these extraluminal appendicoliths to prevent long-term complications, including intra-abdominal abscess.

Modified technique for imaging the wrist and elbow in obese and claustrophobic patients using a non-open standard MRI scanner

ObjectiveIt is challenging to image extremely obese and claustrophobic patients using a standard, non-open, magnetic resonance imaging (MRI) scanner. On the other hand, installing an additional upright or open MRI scanner may not be cost-effective for most practices. Our technique with a patient in a sitting or standing position behind the standard MRI scanner may be helpful in the MR examination of the wrist/elbow in these patients using a standard wrist/elbow coil.Material and methodsWe performed wrist and elbow MRI of extremely obese and claustrophobic patients by using our modified technique with the patient sitting or standing outside the standard non-open MRI scanner. A total number of 20 cases with the following diagnosis were examined: triquetral and scaphoid bone contusions and fractures, scapholunate ligament tears, triangular fibrocartilage complex tear, and biceps tear.ResultsComparison of image quality for diagnostic information between the standard technique and our technique showed no significant difference, which is necessary for making the diagnosis.ConclusionsOur technique enables wrist and elbow imaging of extremely obese and claustrophobic patients who cannot otherwise be imaged using a standard MRI scanner without compromising the image quality that is essential for making a diagnosis.

Orbital apex disorders: Imaging findings and management

Orbital apex disorders include orbital apex syndrome, superior orbital fissure syndrome and cavernous sinus syndrome. These disorders result from various etiologies, including trauma, neoplastic, developmental, infectious, inflammatory as well as vascular causes. In the past, these have been described separately based on anatomical locations of disease process; however, these three disorders share similar causes, diagnostic evaluation and management strategies. The etiology is diverse and management is directed to the causative process. This imaging review summarizes the pertinent anatomy of the orbital apex and illustrates representative pathological processes that may affect this region. The purpose of this review is to provide an update on the current status of diagnostic imaging and management of patients with orbital apex disorders.

Cocaine abuse: Longitudinal MR imaging of lasting diffused leukoencephalopathy

Cocaine use has been known to cause a number of adverse neurological conditions, such as cerebral ischemia and posterior reversible leukoencephalopathy. The radiologic appearance of cocaine-induced leukoencephalopathy is confounded by a common contaminant, levamisole, which is also known to cause multifocal leukoencephalopathy. However, we encountered a case of diffuse leukoencephalopathy in a patient with cocaine use that had extensive involvement of the cerebral white matter, globus pallidi as well as the cerebellum. Our case also presented with a severe clinical presentation, with the patient demonstrating minimal neurologic response after a prolonged period of critical care management. The severe clinical course and diffuse radiologic involvement of our case differs from previously reported cases of cocaine- or levamisole-induced leukoencephalopathy.

Clinical and Neuroimaging Findings in Thalamic Territory Infarctions: A Review: A Review of Thalamic Infarcts

The thalamus is a part of the diencephalon, containing numerous connections between the forebrain and subcortical structures. It serves an important function as a relay center between the cerebral cortex and the subcortical regions, particularly with sensory information. The thalamus also plays a major role in regulating arousal and the levels of awareness. Distinct vascular distribution of the thalamus give rises to different syndromic presentation of thalamic nuclei infarcts. The clinical records and available imaging studies of patients with confirmed thalamic territory infarcts on magnetic resonance imaging (MRI) at the University Hospital of Rochester were reviewed and analyzed. This analysis was then used to provide an effective summary of thalamic vascular anatomy, the clinical symptoms, and syndromes associated with strokes in the affected territories. Specifically, we review the syndromes associated with classic vascular territories, including the anterior, paramedian, inferolateral, and posterior thalamic nuclei, that are supplied by the polar (tuberothalamic), paramedian, inferolateral (thalamogeniculate), and posterior choroidal arteries, respectively. In addition, we will also review the variant thalamic territories and associated infarction syndromes of the anteromedian, central, and posterolateral territories. This review article is aimed to better the clinical and radiologic understanding as well as the diagnosis of classic and variant thalamic territory infarcts. This article will also briefly touch on the recovery of function after thalamic infarcts.

Poland Syndrome with Ipsilateral Hypoplasia of Gluteal Muscles and Contralateral Hidradenitis Suppurativa

Summary Background Poland syndrome (PS) is a rare congenital anomaly associated with absent or hypoplastic pectoralis major muscle and a wide spectrum of ipsilateral thoracic and upper extremity deformities. Hidradenitis suppurativa (HS) is a recurrent inflammatory follicular disease that commonly affects the apocrine-bearing skin and involves follicular occlusion and hyperkeratosis. Case Report We report a case of a 46-year-old male with a history of chronic recurrent hidradenitis suppurativa who was incidentally found to have a simple type of Poland syndrome with incidental hypoplasia of ipsilateral gluteal muscles. Conclusions Not only can PS present with HS, which we describe for the first time, but it is also associated with a wide variability of symptoms such as previously unknown co-existence of gluteal muscles hypoplasia.