Major Radiologic and Clinical Outcomes of Total Spine MRI Performed in the Emergency Department at a Major Academic Medical Center.

BACKGROUND AND PURPOSE: Total spine MRIs are requested by the emergency department when focused imaging can not be ordered on the basis of history or clinical findings. However, their efficacy is not known. We assessed the following: 1) major radiologic and clinical outcomes of total spine MR imaging performed by the emergency department, and 2) whether the presence of a high-risk clinical profile and/or neurologic findings impacts the clinical outcomes. MATERIALS AND METHODS: Total spine MRIs requested by the emergency department during a 28-month period were evaluated for major radiologic (cord compression, cauda equina compression, and other significant findings) and major clinical outcomes (hospital admission during the visit followed by an operation, radiation therapy, or intravenous antibiotics or steroids). Associations between a high-risk clinical profile (cancer, infection, coagulopathy) and/or the presence of neurologic findings and outcomes were assessed. RESULTS: After we excluded trauma or nondiagnostic studies, 321/2047 (15.7%) MRIs ordered during study period were total spine MR imaging; 117/321 (36.4%) had major radiologic and 60/321 (18.6%) had major clinical outcomes (34/60 in <24 hours); and 58/117(49.6%) with major radiologic outcome were treated compared with 2/205 (1.0%) without (OR = 99, P < .001). The presence of both a high-risk clinical profile and neurologic findings concurrently in a patient (142/321) increased the likelihood of major clinical outcomes during the same visit (OR = 3.1, P < .001) and in <24-hours (OR = 2.6, P = .01) compared with those with either a high-risk clinical profile or neurologic findings alone (179/321). CONCLUSIONS: Total spine MR imaging ordered by our emergency department has a high radiologic and significant clinical yield. When a high-risk clinical profile and neurologic findings are both present in a patient, they should be prioritized for emergent total spine MR imaging, given the increased likelihood of clinical impact.

Clinical utility of 2-D anatomic measurements in predicting cough-associated headache in Chiari I malformation.

PURPOSE: Cough-associated headache (CAH) is the most distinctive symptom of patients with Chiari I malformation (CMI) and indicates clinically significant disease. We determined the clinical utility of simple 2D anatomic measurements performed on a PACS workstation by assessing their diagnostic accuracy in predicting CAH in CMI patients. METHODS: Seventy-two consecutive CMI patients (cerebellar tonsillar herniation > 5 mm) with headache seen by neurosurgeons over 6 years were included. Sagittal T1 images were used by two readers to measure: extent of tonsillar herniation, lengths of the clivus and supra-occiput, McRae and pB-C2 lines, as well as clivus-canal, odontoid retroversion, and skull base angles. Neurosurgery notes were reviewed to determine presence of CAH. Mann-Whitney test was used to compare measurements between patients with and without CAH. Predictive accuracy was assessed by receiver operating characteristic (ROC) curve. RESULTS: 47/72 (65.3%) CMI patients reported CAH. Tonsillar herniation with CAH (10.2 mm, 7-14 mm; median, interquartile range) was significantly greater than those without CAH (7.9 mm, 6.3-10.9 mm; p = 0.02). Tonsillar herniation ≥ 10 mm showed sensitivity and specificity of 51% and 68%, and tonsillar herniation > 14 mm showed sensitivity and specificity of 30% and 100%, respectively, for predicting CAH. Other 2D measurements showed no statistically significant differences. CONCLUSIONS: Among the 2D measurements used, only the extent of tonsillar herniation is different between CMI patients with and without CAH. Although CMI is diagnosed with tonsillar herniation of only 5 mm, we found that a much higher extent of herniation is needed to be predictive of CAH.

Report of 2 Novel Presentations of Subcutaneous Fat Necrosis of the Newborn.

Subcutaneous fat necrosis of the newborn (SCFNN) is a rare form of panniculitis classically affecting healthy full-term infants. There are a number of predisposing factors including perinatal asphyxia. The condition generally has a benign course with spontaneous resolution, but monitoring for metabolic complications, in particular the potentially life-threatening complication of hypercalcaemia, is critical. The authors report 2 cases of preterm infants with perinatal asphyxia with atypical presentations of SCFNN: the first with bony involvement resembling Langerhans cell histiocytosis and with follicular pseudocarcinomatous hyperplasia on histology; and the second presenting with a huge haematoma requiring surgical debridement. Both cases were initially erroneously diagnosed as pyogenic infections.

Relationship between Cough-Associated Changes in CSF Flow and Disease Severity in Chiari I Malformation: An Exploratory Study Using Real-Time MRI.

BACKGROUND AND PURPOSE: Currently no quantitative objective test exists to determine disease severity in a patient with Chiari I malformation. Our aim was to correlate disease severity in symptomatic patients with Chiari I malformation with cough-associated changes in CSF flow as measured with real-time MR imaging. MATERIALS AND METHODS: Thirteen symptomatic patients with Chiari I malformation (tonsillar herniation of ≥5 mm) were prospectively studied. A real-time, flow-sensitized pencil-beam MR imaging scan was used to measure CSF stroke volume during rest and immediately following coughing and relaxation periods (total scan time, 90 seconds). Multiple posterior fossa and craniocervical anatomic measurements were also obtained. Patients were classified into 2 groups by neurosurgeons blinded to MR imaging measurements: 1) nonspecific Chiari I malformation (5/13)-Chiari I malformation with nonspecific symptoms like non-cough-related or mild occasional cough-related headache, neck pain, dizziness, paresthesias, and/or trouble swallowing; 2) specific Chiari I malformation (8/13)-patients with Chiari I malformation with specific symptoms and/or objective findings like severe cough-related headache, myelopathy, syringomyelia, and muscle atrophy. The Spearman correlation was used to determine correlations between MR imaging measurements and disease severity, and both groups were also compared using a Mann-Whitney U test. RESULTS: There was a significant negative correlation between the percentage change in CSF stroke volume (resting to postcoughing) and Chiari I malformation disease severity (R = 0.59; P = .03). Mann-Whitney comparisons showed the percentage change in CSF stroke volume (resting to postcoughing) to be significantly different between patient groups (P = .04). No other CSF flow measurement or anatomic measure was significantly different between the groups. CONCLUSIONS: Our exploratory study suggests that assessment of CSF flow response to a coughing challenge has the potential to become a valuable objective noninvasive test for clinical assessment of disease severity in patients with Chiari I malformation.

"Barbell Sign": A Diagnostic Imaging Finding in Progressive Multifocal Leukoencephalopathy.

The recently proposed diagnostic algorithm for progressive multifocal leukoencephalopathy underscores the importance of imaging and emphasizes the role of the radiologist in the diagnostic workup. We describe a case series of patients with visual symptoms and a typical pattern of brain involvement in definite progressive multifocal leukoencephalopathy, for which we have coined the term barbell sign.

Development of a peripheral nerve stimulator-guided technique for equine pudendal nerve blockade.

The aim of this study was to develop and evaluate a procedure for equine pudendal nerve block using a peripheral nerve locator. In the first experiment, six ponies were used to determine the relationship between elicited muscle contractions (anal, perineal or both) and nerves serving the perineal region (pudendal, caudorectal and perineal nerves) when methylene blue dye was injected using the electrolocation technique. This experiment showed that the pudendal nerve was approached effectively when both anal and perineal twitch were elicited during electrolocation. In a second experiment, seven Thoroughbred horses were used to evaluate the appropriate volume of anaesthetic solution for the nerve block. Immediately after euthanasia, lidocaine/methylene blue solution was injected after positive electrolocation. A stained segment of 2 cm or more of the nerve was considered effective and this was evaluated after dissection. Both 10 and 20 mL per injection site resulted in effective nerve staining. Finally, pudendal nerve block was performed and evaluated in 27 horses admitted for selected reproductive surgical procedures including perineoplasty, urethroplasty, clitorectomy in mares and penile examination, phallectomy and urethrostomy in geldings. Surgical time varied from several minutes to 3 h. The choice between lidocaine, mepivacaine or bupivacaine was based on the duration of analgesia required. In mares and males, a volume of 20 mL and 10 mL, respectively, was injected per site. The use of a peripheral nerve stimulator-guided pudendal nerve block is a feasible, safe and reliable alternative for both epidural and general anaesthesia, to provide peri-operative analgesia in clinical equine patients undergoing specific reproductive surgeries.

The Kimberley Hospital Rule (KHR) for urgent computed tomography of the brain in a resource-limited environment.

BACKGROUND: The indications for urgent computed tomography of the brain (CTB) in the acute setting are controversial. While guidelines have been proposed for CTB in well-resourced countries, these are not always appropriate for resource-limited environments. Furthermore, no unifying guideline exists for trauma-related and non-trauma-related acute intracranial pathology. Adoption by resource-limited countries of more conservative scanning protocols, with outcomes comparable to well-resourced countries, would have significant benefit. A multidisciplinary team from Kimberley Hospital in the Northern Cape Province of South Africa adopted the principles defined in the National Institute for Health and Care Excellence (NICE) guideline for the early management of head injury and drafted the Kimberley Hospital Rule (KHR), a proposed unifying guideline for the imaging of acute intracranial pathology in a resource-limited environment. OBJECTIVE: To evaluate the sensitivity and specificity of the KHR. METHODS: A prospective cohort study was conducted in the Northern Cape Province between 1 May 2010 and 30 April 2011. All patients older than 16 years presenting to emergency departments with acute intracranial symptoms were triaged according to the KHR into three groups, as follows: group 1 - immediate scan (within 1 hour); group 2 - urgent scan (within 8 hours); and group 3 - no scan required. Patients in groups 1 and 2 were studied. The primary outcome was CTB findings of clinically significant intracranial pathology requiring acute change in management. RESULTS: Seven hundred and three patients were included. The KHR achieved 90.3% sensitivity and 45.5% specificity, while reducing the number of immediate CTBs by 36.0%. CONCLUSION: The KHR is an accurate, unifying clinical guideline that appears to optimise the utilisation of CTB in a resource-limited environment.

Evaluation of maxillary arterial blood flow in anesthetized cats with the mouth closed and open.

The mouth-gag is a common tool used in veterinary medicine during oral and transoral procedures in cats but its use has recently been associated with the development of blindness. The goal of this study was to investigate whether maximal opening of the mouth affects maxillary artery blood flow in six anesthetized cats. To assess blood flow, the electroretinogram (ERG), brainstem auditory evoked response (BAER) and magnetic resonance angiography (MRA) were evaluated qualitatively with the mouth closed and open. During dynamic computer tomography (CT) examinations, detection of contrast medium in the maxillary artery was quantified by measuring the Hounsfield units (HUs). The peak HU, time to peak and mean HU were determined. Changes ⩾10% of these parameters were considered indicative of altered blood flow. ERG and BAER were normal with the mouth closed in all cats, but was abnormal with the mouth opened maximally in two cats and one cat, respectively. During MRA, blood flow was undetected in either maxillary artery in one cat and reduced in the right maxillary artery in two cats, when the mouth was open. During CT, the peak HU decreased ⩾10% in three cats, the time to peak was ⩾10% longer in two cats, and the mean HU was ⩾10% lower in one cat when the mouth was open. No cat developed apparent blindness or deafness. Maximal opening of the mouth caused alterations in several indicators of blood flow in some individual cats.

Histopathological and immunohistochemical study of air sac lesions induced by two strains of infectious bronchitis virus.

Infectious bronchitis virus (IBV) is a highly contagious respiratory coronavirus of domestic chickens. Although mortality is low, infection with IBV results in substantial losses for the egg and meat chicken industries. Despite the economic importance of IBV and decades of research into the pathogenesis of infection, significant gaps in our knowledge exist. The aim of this study was to compare the early progression of air sac lesions in birds receiving a vaccine strain of the virus or a more virulent field strain. The air sacs are lined by different types of epithelia and are relatively isolated from the environment, so they represent a unique tissue in which to study virus-induced lesions. Both the pathogenic and vaccine strains of the virus produced significant lesions; however, the lesions progressed more rapidly in the birds receiving the pathogenic strain. Immunohistochemistry demonstrated that in birds infected with the pathogenic strain of virus, IBV spike protein is detected first in the ciliated cells lining the air sac. These preliminary data provide important clues regarding potential mechanisms for IBV tissue tropism and spread and show that the nature of the virus isolate influences the early progression of IBV infection.

Computed tomography of temporal bone fractures and temporal region anatomy in horses.

BACKGROUND: In people, specific classifications of temporal bone fractures are associated with clinical signs and prognosis. In horses, similar classifications have not been evaluated and might be useful establishing prognosis or understanding pathogenesis of certain types of trauma. HYPOTHESIS/OBJECTIVES: We hypothesized associations between temporal bone fracture location and orientation in horses detected during computed tomography (CT) and frequency of facial nerve (CN7) deficit, vestibulocochlear nerve (CN8) deficit, or temporohyoid osteoarthropathy (THO). Complex temporal region anatomy may confound fracture identification, and consequently a description of normal anatomy was included. ANIMALS: All horses undergoing temporal region CT at our hospital between July 1998 and May 2008. METHODS: Data were collected retrospectively, examiners were blinded, and relationships were investigated among temporal bone fractures, ipsilateral THO, ipsilateral CN7, or ipsilateral CN8 deficits by Chi-square or Fischer's exact tests. Seventy-nine horses had CT examinations of the temporal region (158 temporal bones). RESULTS: Sixteen temporal bone fractures were detected in 14 horses. Cranial nerve deficits were seen with fractures in all parts of the temporal bone (petrosal, squamous, and temporal) and, temporal bone fractures were associated with CN7 and CN8 deficits and THO. No investigated fracture classification scheme, however, was associated with specific cranial nerve deficits. CONCLUSIONS AND CLINICAL IMPORTANCE: Without knowledge of the regional anatomy, normal structures may be mistaken for a temporal bone fracture or vice versa. Although no fracture classification scheme was associated with the assessed clinical signs, simple descriptive terminology (location and orientation) is recommended for reporting and facilitating future comparisons.

Comparison of paper print and soft copy reading in plain paediatric radiographs.

With the introduction of a Picture Archiving and Communication System, Computed (CR) and Digital Radiography (DR), reading digital images takes place from a computer screen. Laser paper print rather than laser film would be a significantly more cost-effective option for hard copy production, but would need to demonstrate acceptable diagnostic quality compared to the reference standard of screen reading. A comparative study of 51 digital paediatric CR radiographs presented in laser paper print and soft copy format to determine the diagnostic value of the paper print when compared to the reference standard of screen reading. Chest radiography had a poor sensitivity of 66.1% while musculoskeletal and abdominal radiography had acceptable sensitivities of 90% and 99%, respectively. Specificity was excellent for the different regions (98.6-99.5%). The paper print format should not be used for diagnostic purposes in paediatric chest radiography, but may still be used for demonstration when accompanied by the radiology rapport obtained from soft copy reading. Further studies would be needed to investigate the use of paper prints in abdominal and musculoskeletal radiography owing to the low number of abdominal radiographs and lack of musculoskeletal case variety in our study.

A lectin histochemical study of the thoracic respiratory air sacs of the fowl.

The lectin-binding characteristics of the epithelial lining of the thoracic air sacs of the chicken were determined. Con A, LCA and PSA bound to the apical membrane as well as to the cytoplasm distal to the nucleus of the surface epithelium, indicated the presence of a-linked mannose as well as N-acetylchitobiose-linked alpha-fucose residues in the glycoproteins. GSL I bound to the apical membrane and cytoplasm distal to the nucleus, but not to the cilia of the epithelium, where-as MPL, DBA and RCA120 bound to the apical membrane, cilia and cytoplasm, indicated the presence of a-linked N-acetylgalactosamine residues. However, neither SJA or SBA showed any binding, indicating the absence of beta anomers of galactosyl (beta1.3)N-acetylgalactosamine and beta-linked N-acetylgalactosamine residues. UEA I bound to the apical membrane and cilia, as well as to the cytoplasm of a few cells, indicated the presence of alpha-linked fucose residues. PNA bound to the apical membrane of some, but not all, surface epithelium cells, indicated the presence of galactosyl (beta1.3)N-acetylgalactosamine residues. WGA bound to the apical membrane and cilia, as well as to the cytoplasm of a few cells, indicated the presence of neuraminic acid residues.

Light and electron microscopic study of the thoracic respiratory air sacs of the fowl.

There are conflicting reports in the existing literature on the nature of the epithelial lining and the content of the supporting connective tissue of the respiratory air sacs of birds. The present study describes the light and electron microscopic structure of the thoracic air sacs of the fowl. A simple squamous epithelium lined the greater part of the thoracic air sacs. The squamous cells characteristically contained vesicles filled with lamellar or myelinoid material. Localized areas of cuboidal to columnar ciliated epithelium were randomly distributed and often associated with underlying blood vessels. Isolated ciliated cells first appeared on squamous or low cuboidal cells and increased in frequency as the cells became taller. Occasional basal and goblet cells were seen between the ciliated columnar cells. A fibrous connective tissue stroma supported the epithelium. Fine elastic fibres were particularly prevalent immediately below the epithelium. Isolated smooth muscle myocytes were present in the connective tissue stroma. A sheet of smooth muscle extended some distance into the membrane from the attachment of the latter to the body wall. Numerous small blood vessels, lymphatics and occasional nerve bundles were observed in the stroma.

An anatomical study of the respiratory air sacs in ostriches.

An accurate description of the number, location and relative position of the air sacs and their diverticula in the ostrich is essential for a better understanding of the pathogenesis of air sacculitis in this bird. The air sacs were studied in ten ostriches of varying ages by latex or silicone casting of the respiratory tract and dissection. Results revealed that the air sacs of the ostrich conform to the general pattern in birds. Cervical, lateral and medial clavicular, cranial and caudal thoracic, and abdominal air sacs are present. The left and right medial clavicular air sacs fuse with each other ventrally to the trachea to form a single, median compartment. A unique, large gastric diverticulum which covers the caudal aspects of the proventriculus and gizzard originates from the median compartment of the clavicular air sac. The lateral clavicular air sacs and their diverticula are similar to those of other bird species, with the exception that humeral diverticula are absent. Both abdominal air sacs are relatively small, with the left sac being the larger. Perirenal and femoral diverticula, similar to those found in other bird species, are present. However, the entire femur is aerated by the femoral diverticulum which also forms a large, subcutaneous division caudally and caudo-laterally to the femur. The presence of this subcutaneous part has practical implications for injury and intramuscular injections. The number and location of ostia connecting the air sacs to the bronchial tree are generally similar to those reported in other bird species.

Macroscopic blood supply to the hypophysis and hypothalamus of the ostrich (Struthio camelus).

The branching pattern of the Aa. carotes internae and the macroscopic blood supply to the hypophysis and hypothalamus of the ostrich were studied on ten dissected acrylic vascular-injected heads and ten corrosion preparations of acrylic vascular casts of the head. The A. carotis cerebralis was found to be the only source of blood supply to the hypophysis and hypothalamus. The neurohypophysis was supplied by the caudal hypophyseal and infundibular arteries. The pars distalis was supplied by portal vessels from the ventral hypothalamic region, and it also received arterial blood directly from the infundibular arteries. The hypothalamus received blood from the Aa. infundibulares. A. ventralis tecti mesencephali and A. preopticae.

The osteology of the African elephant (Loxodonta africana): vertebral column, ribs and sternum.

The vertebral column, sternum and ribs of the African elephant were studied and illustrated. In the cervical series, the vertebrae are characterized by very short (compressed) vertebral bodies and short spinous processes. There are 20-21 thoracic vertebrae that carry ribs, and three lumbar vertebrae. The neural arches of the five sacral vertebrae fuse with each other as well as with the wings of the ilium, while the intervertebral discs do not ossify and the vertebral bodies remain separate. There are 19-21 caudal vertebrae. In the latter, the neural arches of only the first five to six vertebrae fuse dorsally, the vertebral foramens of the other vertebrae as well as the vertebral canal remain open dorsally. The body of the first rib is greatly expanded while that of the last three to four ribs are reduced. The cartilages of the first six ribs articulate with the sternum, the last five to six ribs do not bear costal cartilages and are not attached to the costal arch. The sternum consists of five sternabrae that form three approximately equal, but separate, segments. The first segment is formed by the first sternabra, the second segment is formed by the second to fourth sternabrae and the last segment is formed by the fifth sternabra. The first and second sternabrae articulate with each other by means of a synovial joint, the second to fourth sternabrae are fused to each other and the fourth and fifth sternabrae are loosely attached to each other by connective tissue.

The skull and mandible of the African elephant (Loxodonta africana).

In the present study the bones of the skull, excluding the hyoid apparatus, are described. All the bones are aerated by sinuses. In the occipital bone the squamous part is aerated from the sinus of the parietal bone, the lateral part is aerated from the tympanic bulla and the basal part from the sinus of the basisphenoid bone. Condylar foramens and hypoglossal canals are absent. A small interparietal bone is present at birth. At an early age it fuses with the surrounding cranial bones. The squamous part of the temporal bone lies sagittally in young animals, but moves progressively to a transverse plane as the animals age. A foramen lacerum is represented by jugular and oval foramens and the carotid canal. The body of the basisphenoid bone is excavated by the massive maxillary tuberosity. The latter extends to the oval foramen and contains the developing molar teeth. The ethmoturbinate, nasal and lacrimal bones are exceptionally small. In old bulls the palatine process of the incisive bones and their sinuses are gradually displaced by the palatine process of the maxillae.

Sperm-storage tubules in the vagina of the ostrich (Struthio camelus).

Sperm-storage tubules have been described in a number of species of birds. The presence of these tubules in the Rhea has been mentioned, but no description of these structures in ratites is available. The purpose of this study was to determine the presence and morphology of sperm-storage tubules in the vagina of the ostrich. The study was performed with the use of conventional light- and electron-microscopic techniques. Sperm-storage tubules were located in a 200-mm-wide band of the vagina adjacent to the utero-vaginal junction. The tubules were mostly branched and slightly coiled and lined by columnar epithelial cells. The cells contained a basal nucleus and displayed extensive apical junctional complexes. TEM revealed sperm in all the tubules examined.

Evidence for cryptosporidial infection as a cause of prolapse of the phallus and cloaca in ostrich chicks (Struthio camelus).

Cloacas of male ostrich chicks that had suffered prolapse of the phallus and cloaca were compared with cloacas of normal ostrich chicks of both sexes from the same area. Heavy infection of the cloacal and bursal tissue with Cryptosporidium sp. was present in all the cases of prolapse, while no cryptosporidia were observed in the normal chicks. Histopathological lesions as described in cryptosporidial infection in other species were present in the infected cloacas. These included loss of the microvillous border and epithelial hyperplasia and degeneration, which was indicated ultrastructurally by vacuolation of the apical cytoplasm, swelling of organelles, and nuclear changes. It is suggested that these lesions, in combination with the anatomy of the male ostrich cloaca, may be responsible for prolapse of the phallus and cloaca.