Frederick Ott

Effect of patient positioning on cerebrospinal fluid opening pressure

Background: Prone is the preferred patient position for fluoroscopic-guided lumbar puncture (LP). Normative data for cerebrospinal fluid (CSF) opening pressure (OP) exist for lateral decubitus (LD) positioning only and have not been defined for the prone position. This study compares CSF OP values in the prone and LD positions and examines the effect of body mass index (BMI) on OP. Methods: Patients undergoing diagnostic or therapeutic fluoroscopic-guided LP were recruited prospectively at 2 tertiary care centers from 2009 to 2012. Following prone fluoroscopic-guided LP, patients were rolled to the LD position for repeat CSF OP measurement. In addition to comparing the mean OP in each position, the relationships between OP, body position, and BMI were also explored. Results: Fifty-two patients were enrolled. A mean OP difference of 1.2 cm H2O was observed (prone: 26.5 cm H2O; LD: 27.7 cm H2O; P = 0.07). No correlation between CSF OP and BMI was seen in either position. Conclusions: No statistically or clinically significant difference between prone and LD OP was identified. BMI does not appear to affect CSF OP measurement in either position.

Head/Neck and Spine Imaging Variants: Introduction

This book is separated into six different sections based on regional anatomy for the purpose of addressing the common modalities (such as CT or MRI), imaging sequences (particularly various MR sequences), and protocols (such as slice thickness or windowing) in order to identify each imaging variant in that region. These include: Sinonasal Variants (Chap. 2), Orbital Variants (Chap. 3), Head and Neck Variants (Chap. 4), Temporal Bone Variants (Chap. 5), Cervical and Thoracic Spine Variants (Chap. 6), and Lumbar Spine Variants (Chap. 7). Notably, the Head and Neck Variants chapter covers a wider range of anatomy and physiology (e.g., mucosal abnormalities, thyroid variants, salivary gland variants, Eagle syndrome, vascular variants and PET-CT variants) and thus is a bit more cursory because of the way neck CT imaging is routinely interpreted; perhaps this will be expounded on further in future editions, since some topics are quite vast in that region, and the anatomy is relatively compact. Furthermore, each of the above-mentioned six subjects tend to be subdivided further by sub-anatomic regions (e.g., “ossicular variants” within the Temporal Bone Variants chapter, “lacrimal gland” within the Orbital Variants chapter), and thus the variants of such regions are grouped together so that the differential diagnosis for true pathology and comparison to a known variant is practical; i.e. so a confident identification of the variant can be reached during routine image interpretation. Relevant references are provided for each subject. The goal of this text was to provide a quick, pictorial review with critical anatomy and imaging characteristics to facilitate prompt recognition of each variant; the reader is encouraged to review any of the numerous references included in each section for more in-depth learning.

Neck Soft Tissue Variants

There are multiple developmental variations of soft-tissue neck structures that can be detected on computed tomography (CT), magnetic resonance imaging (MRI), and 18 fluro-deoxy-glucose position emission tomography (FDG-PET). These need to be recognized and differentiated from actual pathologies. There can also be benign lesions involving the soft tissue neck that are caught incidentally while the study is obtained to evaluate other pathologies. Being aware of these variations and certain common benign lesions is quite important. If such variants or “don’t touch lesions” are diagnosed correctly, this can prevent unnecessary patient anxiety, possible invasive procedures, and potential complications. For example, being knowledgeable about the common FDG-PET findings of brown fat activation-related FDG uptake in certain parts of the body prevents misdiagnosis of disease progression and possibly unnecessary biopsies.

Temporal Bone Variants

Temporal bone imaging has a well-deserved reputation as being one of the more challenging aspects of radiology. To paraphrase a neurotology colleague, an amazing amount of intricate anatomy is packed into a very small box. Furthermore, the pathology affecting these structures can be very subtle and affect minute areas. Understanding the myriad appearances of normal structures in unusual places or of unexpected size is quite important. Frequently, these variations are of no consequence but occasionally a similar structure of a comparable size and location that is asymptomatic in one person may be problematic in another.

Normal Variants of the Lumbar and Sacral Spine

Normal variants of the lumbar spine are well described but can simulate pathology if not recognized and understood.

Cervical and Thoracic Spine: Normal Variants and Artifacts

Imaging of the cervical spine is a routine part of a radiology practice. Familiarity with the appearance of the cervical and thoracic spinal vertebrae is critical to providing accurate imaging interpretation. In particular, the complex development of the spine, particularly the cervical spine, merits attention to aid in recognition of spinal normal anatomic variants.

Concomitant Acute Toxic Leukoencephalopathy and Posterior Reversible Encephalopathy Syndrome: Concomitant ATL and PRES

Posterior reversible encephalopathy syndrome (PRES) and acute toxic leukoencephalopathy (ATL) are both potentially reversible clinicoradiologic entities. Although their magnetic resonance imaging (MRI) findings differ, rarely both may occur simultaneously in acutely encephalopathic patients. Our aim was to determine the incidence and causes of concomitant “ATL‐PRES.”

Imaging features of neurotoxoplasmosis: A multiparametric approach, with emphasis on susceptibility-weighted imaging

Background Neurotoxoplasmosis is a common opportunistic infection in HIV/AIDS patients. Imaging identification of neurotoxoplasmosis assists in timely treatment. Purpose To delineate the frequency of imaging abnormalities in patients with neurotoxoplasmosis on different MR sequences with a particular focus on SWI, and NCCT. Material and methods The PACS database was retroactively searched over a 5-year period for patients with neurotoxoplasmosis who underwent MRI with SWI. Included patients had imaging features of neurotoxoplasmosis based on consensus review by two neuroradiologists, a clinical diagnosis of neurotoxoplasmosis at the time of MRI, and diagnostic confirmation based on positive serum or CSF serology or histopathology; 15 patients were included. The number of abnormal foci with restricted diffusion, increased FLAIR signal, intrinsic T1 hyperintensity, abnormal enhancement (CE-T1WI), and intrinsic hyperdensity on CT were recorded. Results Intralesional susceptibility signal (ISS) foci on SWI were observed in 93.3% of patients with neurotoxoplasmosis (mean size 5.2 ± 3.8 mm). The average number of ISS foci was 3.9 per patient; 3/15 (20.0%) had a single ISS. Amongst other MR sequences, hyperintense FLAIR foci were the most common abnormalities observed (12.4 lesions/patient), followed by enhancing foci (8.2 lesions/patient), foci of restricted diffusion (7.1 lesions/patient), and intrinsic T1 hyperintense foci (3.4 lesions/patient). Abnormalities were least frequently observed on NCCT: abnormalities were identified in 5/15 (33.3%) patients, at a rate of 0.4 lesions/patient. Conclusion ISS foci are present in the vast majority of neurotoxoplasmosis patients, likely representing hemorrhage. The incidence and frequency of other abnormal foci are highest on FLAIR, and lowest on NCCT.