Glial tumors in brodmann area 6: spread pattern and relationships to motor areas.

The posterior frontal lobe of the brain houses Brodmann area 4, which is the primary motor cortex, and Brodmann area 6, which consists of the supplementary motor area on the medial portion of the hemisphere and the premotor cortex on the lateral portion. In this area, safe resection is dependent on accurate localization of the motor cortex and the central sulcus, which can usually be achieved by using thin-section imaging and confirmed by using other techniques. The most reliable anatomic landmarks are the "hand knob" area and the marginal ramus of the cingulate sulcus. Postoperatively, motor deficits can occur not only because of injury to primary motor cortex but also because of injury to the supplementary motor area. Unlike motor cortex injury, the supplementary motor area syndrome is transient, if it occurs at all. On the lateral hemisphere, motor and language deficits can also occur because of premotor cortex injury, but a dense motor deficit would indicate subcortical injury to the corticospinal tract. The close relationship of the subcortical motor fibers and premotor cortex is illustrated. In contrast to the more constant landmarks of the central sulcus and marginal ramus, which aid in preoperative localization, the variable interruptions in the precentral and cingulate sulci of the posterior frontal lobe seem to provide "cortical bridges" for spread of infiltrating gliomas.

CT findings in temporal bone osteoradionecrosis.

PURPOSE: The goal of this study was to describe computed tomographic findings in patients with clinically proven temporal bone (TB) osteoradionecrosis (ORN) (TB-ORN). MATERIALS AND METHODS: Computed tomographic scans of 20 patients were retrospectively evaluated for bony and soft tissue abnormalities. Clinical severity was graded based on level of therapy administered: mild (observation), moderate (antibiotics/hyperbaric oxygen), or severe (surgery). RESULTS: Radiation dose to the primary tumor ranged from 30 to 75.6 Gy. Time to onset of ORN from completion of radiation therapy was 2 to 22 years (median, 7 years). CLINICAL FINDINGS: exposed bone, 20 of the 20 patients; otorrhea, 17 of the 20 patients; hearing loss, 11 of the 20 patients; otalgia, 10 of the 20 patients; facial nerve paralysis, 2 of the 20 patients; gait imbalance, 2 of the 20 patients. Computed tomographic findings: external auditory canal erosions, 18 of the 20 patients; mastoid effusion, 18 of the 20 patients; mastoid bony coalescence, 5 of the 20 patients; enhancing soft tissue, 6 of the 20 patients; soft tissue gas, 6 of the 20 patients; temporomandibular joint/condylar erosion, 3 of the 20 patients.Three patients developed an abscess. CONCLUSION: Mastoid effusion and external auditory canal erosions are commonly seen with TB-ORN. Clinically moderate or severe cases of TB-ORN are more likely to demonstrate enhancing soft tissue (P = 0.002), soft tissue gas (P = 0.002), and temporomandibular joint involvement (P = 0.07).

Superimposed infection in mandibular osteoradionecrosis: diagnosis and outcomes.

BACKGROUND: Radiation therapy can result in osteoradionecrosis (ORN) and mucosal ulceration predisposing to infection. METHODS: Fourteen patients presenting with infectious sequelae related to mandibular ORN were retrospectively reviewed. RESULTS: In most patients, infection followed diagnosis of ORN; but in 4 patients, ORN was not diagnosed until after the time of infection and imaging. An early imaging finding of ORN was lingual cortical defects near the last molar. Pain followed by erythema, purulent drainage, and subperiosteal abscess by imaging were the most common signs of infection. In most patients, conservative management eventually failed and segmental mandibulectomies were required. CONCLUSIONS: Soft tissue infection with characteristic bone findings such as subperiosteal abscess and cortical bone erosions helps to distinguish infected ORN from recurrent tumor or sterile ORN. In patients previously treated with radiation who present with infection, pain or an avid PET scan with bone involvement, the mandible should be scrutinized.

Deformable anatomic templates embed knowledge into brain images: part 2. Validation using functional magnetic resonance imaging of the motor hand.

OBJECTIVE: This study evaluated the concordance between the Deformable Anatomic Template (DAT)-identified origin of motor hand fibers and localization of the motor cortex of the hand by functional magnetic resonance imaging (fMRI). METHODS: Preoperative fMRI during hand motor tasks was performed on 36 hemispheres in 26 patients with gliomas in or near eloquent areas. Reformatted volume-rendered surface images were labeled with the DAT's hand motor fibers and fMRI data. Five reviewers assessed the data for concordance. RESULTS: Available fMRI data were diagnostically usable in 92% (33/36 analyzed hemispheres), with DAT anatomic accuracy in the remaining cases. The DAT prediction and fMRI findings were concordant in all 9 normal hemispheres and in 20 (83%) of 24 glioma-bearing hemispheres. The 4 discordant cases resulted from substantial mass effect by large frontal tumors. CONCLUSIONS: This study validated DAT's anatomic atlas and alignment process for the expected position of the motor cortex of the hand.

Multidetector CT evaluation of active extravasation in blunt abdominal and pelvic trauma patients.

Timely localization of a bleeding source can improve the efficacy of trauma management, and improvements in the technology of computed tomography (CT) have expedited the work-up of the traumatized patient. The classic pattern of active extravasation (ie, administered contrast agent that has escaped from injured arteries, veins, or urinary tract) at dual phase CT is a jet or focal area of hyperattenuation within a hematoma that fades into an enlarged, enhanced hematoma on delayed images. This finding indicates significant bleeding and must be quickly communicated to the clinician, since potentially lifesaving surgical or endovascular repair may be necessary. Active extravasation can be associated with other injuries to arteries, such as a hematoma or a pseudoaneurysm. Both active extravasation and pseudoaneurysm (unlike bone fragments and dense foreign bodies) change in appearance on delayed images, compared with their characteristics on arterial images. Other clues to the location of vessel injury include lack of vascular enhancement (caused by occlusion or spasm), vessel irregularity, size change (such as occurs with pseudoaneurysm), and an intimal flap (which signifies dissection). The sentinel clot sign is an important clue for locating the bleeding source when other more localizing findings of vessel injury are not present. Timely diagnosis, differentiation of vascular injuries from other findings of trauma, signs of depleted intravascular volume, and localization of vascular injury are important to convey to interventional radiologists or surgeons to improve trauma management.

Real-time atlas-based stereotactic neuronavigation.

BACKGROUND: Surgery for tumors in eloquent brain faces immense challenges when attempting to maximize resection and avoid neurological deficits. OBJECTIVE: In order to give the surgeon real-time atlas-based anatomic information linked to the patient's anatomy, we developed a software-based interface between deformable anatomic templates (DATs) and an intraoperative navigation system. METHODS: Magnetic resonance imaging (MRI), diffusion tensor imaging, and/or functional MRI were performed on 3 patients preoperatively for the purposes of tumor resection by the use of neuronavigation. The DAT was registered to the patients' navigation coordinate system and utilized coordinates from the navigation system during surgery. This provided the surgeon with a list of proximal anatomic and functional structures and a real-time image of the atlas at that location fused to the patient's MRI. The clinical feasibility of this approach was evaluated during the resection of 3 eloquent tumors (right postcentral gyrus, left inferior frontal gyrus, and left occipital cuneus gyrus). RESULTS: Tumor resection was performed successfully in all 3 patients. With the use of the coordinates from the navigation system, anatomic and functional structures and their distances were visualized interactively during tumor resection by using the DAT. CONCLUSION: This is a proof of concept that an interactive atlas-based navigation can provide detailed anatomic and functional information that supplements MRI, diffusion tensor imaging, and functional MRI. The atlas-based navigation generated distances to important anatomic structures from the navigation probe tip. It can be used to guide direct electrical stimulation and highlight areas to avoid during tumor resection. ABBREVIATIONS: DAT, deformable anatomic templateDES, direct electrical stimulationDTI, diffusion tensor imagingfMRI, functional magnetic resonance imaging.