Hoffmann sign: clinical correlation of neurological imaging findings in the cervical spine and brain.

STUDY DESIGN: Retrospective validity study. OBJECTIVE: To investigate the relationship between Hoffmann sign and radiographical evidence of cervical spinal cord compression and brain lesions. SUMMARY OF BACKGROUND DATA: Clinical significance of Hoffmann sign remains controversial with conflicting reports regarding its sensitivity and specificity and its usefulness. METHODS: Patients were divided into 2 groups according to the presence of Hoffmann sign on physical examination. Imaging studies were blindly examined by 2 observers for possible cervical and brain lesions. The sensitivity, specificity, positive predictive value, negative predictive value, as well as accuracy for Hoffmann sign as it relates to cervical spinal cord compression and brain pathology, were calculated. RESULTS: Of the 91 patients with a positive Hoffmann sign, 32 (35%) showed severe cervical cord compression and/or myelomalacia. Forty-seven of these patients had brain imaging studies, and 5 (10%) had positive findings. There were 80 patients in the negative Hoffmann sign or control group. Twenty-one (27%) of them had severe cervical cord compression and/or myelomalacia. Twenty-three of these control patients underwent neurological imaging of the brain, and 2 (8%) had positive findings. Hoffmann sign was found to have 59% sensitivity, 49% specificity, 35% positive predictive value, and 72% negative predictive value for cervical cord compression. For brain pathology, sensitivity was 71%, specificity 33%, positive predictive value 10%, and negative predictive value 95%. CONCLUSION: Hoffmann sign has too low a positive predictive value to be relied upon as a stand-alone physical examination finding and is not a reliable screening tool for solely predicting the presence of cervical spinal cord compression or brain pathology. LEVEL OF EVIDENCE: 2.

Independent assessment of a new pedicle probe and its ability to detect pedicle breach: a cadaveric study.

OBJECT: The authors undertook an independent, non-industry funded cadaveric study to evaluate the efficacy of a pedicle-probing device, which uses impedance measurement to warn of impending and actual pedicle screw breach. METHODS: A previously validated fresh-frozen cadaver model (saline-soaked spine) was used. Individuals at 3 levels of training (attending spine surgeon, orthopedic surgery resident, and medical student) used a cannulated pedicle-probing device to cannulate each of the levels between T-2 and S-1. Each pedicle was cannulated freehand using 2 approaches: 1) a standard trajectory through the middle of the pedicle, and 2) a medial trajectory aimed to breach the medial wall of the pedicle. A 16-slice helical CT scanner was used. The images were interpreted and analyzed by 2 orthopedic spine surgeons and a neuroradiologist. RESULTS: The sensitivity of the pedicle probe to detect impending breach or breach of 4 mm or less was 90.06%. The sensitivity in detecting medial wall breach was 95.8%. The positive predictive value was 87.1%. The device detected medial breach more often than lateral breach. CONCLUSIONS: This study showed that this pedicle-probing device could reasonably be used to detect impending breach and actual breach of 4 mm or less. Medial breach was detected better than lateral breach. Use of the pedicle probe may improve patient safety.

Advanced neuroimaging in children with nonaccidental trauma.

Physical abuse associated with nonaccidental trauma (NAT) affects approximately 144,000 children per year in the USA and, frequently, these injuries affect the developing brain. Most infants with suspected NAT are initially evaluated by skull X-rays and computed tomography to determine whether fractures are present, the severity of the acute injury and the need for urgent neurosurgical intervention. Increasingly, magnetic resonance imaging (MRI) is conducted as it provides additional diagnostic and prognostic information about the extent and nature of the injury. In this review, we examine 4 MRI techniques as they apply to children who present acutely after NAT. Susceptibility-weighted imaging is a 3-D high-resolution MRI technique that is more sensitive than conventional imaging in detecting hemorrhagic lesions that are often associated with diffuse axonal injury (DAI). Magnetic resonance spectroscopy acquires metabolite information reflecting neuronal integrity and function from multiple brain regions and provides a sensitive, noninvasive assessment of neurochemical alterations that offers early prognostic information regarding outcome. Diffusion-weighted imaging (DWI) is based on differences in the diffusion of water molecules within the brain and has been shown to be very sensitive in the early detection of ischemic injury. It is now being used to study the direct effects of traumatic injury as well as those due to secondary ischemia. Diffusion tensor imaging is a form of DWI and allows better evaluation of white matter fiber tracts by taking advantage of the intrinsic directionality (anisotropy) of water diffusion in the human brain. It has been shown to be useful in identifying white matter abnormalities after DAI when conventional imaging appears normal. Although these imaging methods have been studied primarily in adults and children with accidental traumatic brain injury, it is clear that they have the potential to provide additional value in the imaging and clinical evaluation of children with NAT.

Hypopharyngeal cancer.

Hypopharyngeal cancers are usually squamous cell carcinomas (SCCs) that has the worst prognosis among the head and neck cancers. Overall, 5-year survival rate remains poor despite recent improvements in diagnostic imaging, radiation and chemotherapy, and improved surgical techniques. Hypopharyngeal cancers tend to present with advanced primary disease, and nodal metastasis is highly likely. The most important features determining prognosis are the size and extent of local spread of the primary carcinoma and the extent of involvement of regional lymph nodes. Distant metastasis at presentation is more common in hypopharyngeal cancers than in other head and neck cancers. Poor survival rate is partly due to emergence of second primary cancers but also to development of distant metastasis. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) remain the mainstay of initial radiological evaluation of hypopharyngeal cancer. Imaging usually results in upstaging of the tumor at presentation. Meticulous evaluation of the extent of the primary tumor with attention to spread to the subsites of the hypopharynx, larynx, and cartilage invasion are necessary for accurate staging. After surgery and radiation therapy, it is difficult with CT and MR to differentiate residual and recurrent tumor from edema and scarring. Fluorine 18-fluoro-deoxy-glucose -positron emission tomography (FDG-PET) has high sensitivity in detection of occult, residual, and recurrent tumors but has low specificity. Combined PET and CT increase specificity and are increasingly being used to image posttreatment cases. Other newer imaging modalities such as diffusion-weighted imaging (DWI), MR spectroscopy, and MRI with superparamagnetic iron oxide (SPIO) contrast agent are reported to be useful and should be used more widely in difficult cases.

Relationship between opioid therapy, tissue-damaging procedures, and brain metabolites as measured by proton MRS in asphyxiated term neonates.

To examine the effects of opioid and tissue-damaging procedures (TDPs) [i.e. procedures performed in the neonatal intensive care unit (NICU) known to result in pain, stress, and tissue damage] on brain metabolites, we reviewed the medical records of 28 asphyxiated term neonates (eight opioid-treated, 20 non-opioid treated) who had undergone magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) within the first month of life as well as eight newborns with no clinical findings of asphyxial injury. We found that lower creatine (Cr), myoinositol (Ins), and N-acetylaspartate (NAA)/choline (Cho) (p < or = 0.03) and higher Cho/Cr and glutamate/glutamine (Glx) Cr (p < or = 0.02) correlated with increased TDP incidence in the first 2 d of life (DOL). We also found that occipital gray matter (OGM) NAA/Cr was decreased (p = 0.03) and lactate (Lac) was present in a significantly higher amount (40%; p = 0.03) in non-opioid-treated neonates compared with opioid-treated neonates. Compared with controls, untreated neonates showed larger changes in more metabolites in basal ganglia (BG), thalami (TH), and OGM with greater significance than treated neonates. Our data suggest that TDPs affect spectral metabolites and that opioids do not cause harm in asphyxiated term neonates exposed to repetitive TDPs in the first 2-4 DOL and may provide a degree of neuroprotection.

Reliability in detection of hemorrhage in acute stroke by a new three-dimensional gradient recalled echo susceptibility-weighted imaging technique compared to computed tomography: a retrospective study.

PURPOSE: To compare the sensitivity of magnetic resonance (MR) susceptibility-weighted imaging (SWI) with conventional MR sequences and computed tomography (CT) in the detection of hemorrhage in an acute infarct. MATERIALS AND METHODS: A series of 84 patients suspected of having acute strokes had both CT and MR imaging (MRI) scans with diffusion-weighted imaging (DWI) and SWI. The SWI sequence is a new high-resolution three-dimensional (3D) imaging technique that amplifies phase to enhance the magnitude contrast. RESULTS: Thirty-eight of 84 cases showed abnormal DWI consistent with acute infarct. Of the 38, SWI showed evidence of hemorrhage in 16 cases, compared to eight cases with spin echo (SE) T2, seven cases with fluid attentuated inversion recovery (FLAIR), and only five cases with CT. In a subset of 17 cases of acute infarct who had both two-dimensional gradient recalled echo (2D-GRE) T2*-weighted imaging and SWI, in addition to conventional MRI, evidence of hemorrhage was seen in 10 cases using SWI, compared to seven cases with 2D-GRE T2*. CONCLUSION: SWI proved to be a powerful new approach for visualizing hemorrhage in acute stroke compared to CT and conventional MRI methods.