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Purpose: To determine the importance of obtaining precontrast T1-weighted magnetization transfer (MT) MR images for better interpretation contrast-enhanced T1-weighted MT images., Methods: One hundred fifty-five patients referred for MR imaging of the brain were examined prospectively with noncontrast T1-weighted imaging, noncontrast T1-weighted imaging with MT, contrast-enhanced T1-weighted imaging, and contrast-enhanced T1-weighted imaging with MT. In the patients who had abnormally increased signal intensity on postcontrast images (with or without MT), the four imaging sequences were evaluated with regard to number of lesions and lesional signal intensity. For each of the sequences, two experienced neuroradiologists subjectively graded the lesions on a scale of 1 to 4 (4 being the most conspicuous) with regard to abnormally increased signal intensity., Results: Twenty-two of the 155 patients had increased signal intensity on one or more of the postcontrast sequences. Eight of these 22 patients had increased signal intensity of one or more lesions on images without MT. All these lesions were seen better on images obtained with MT. An additional six of the 22 patients had increased signal intensity of one or more lesions on images obtained with MT that was not detected on images obtained without MT. Eight of the 22 patients had no high signal intensity on noncontrast images with or without MT. One of the eight had increased number and conspicuity of lesions on postcontrast MT images., Conclusions: A significant number of patients had increased signal intensity on noncontrast T1-weighted images with MT that was not seen on noncontrast T1-weighted images without MT. This high signal intensity was also visible on postcontrast MT images, and would have been mistaken for pathologic enhancement if noncontrast MT images had not been available for comparison.

Purpose: To determine the computed tomographic (CT), magnetic resonance (MR) imaging, and angiographic findings of papillary endolymphatic sac tumors., Materials and Methods: Clinical and imaging studies in 20 patients (aged 17-65 years) with histopathologically proved papillary endolymphatic sac tumors were retrospectively reviewed. Patients underwent CT (n = 18), MR imaging (n = 15), or angiography (n = 12). CT scans were evaluated for bone erosion and calcification; MR images, for signal intensity, enhancement patterns, and flow voids; and angiograms, for tumoral blood supply., Results: All tumors were destructive and contained calcifications centered in the retrolabyrinthine region at CT. The MR imaging appearance varied with lesion size; 12 of 15 tumors showed increased signal intensity at T1-weighted imaging. The high-signal-intensity area was circumferential in lesions 3 cm or smaller and was scattered throughout the lesion in advanced tumors. Only tumors larger than 2 cm had flow voids. The blood supply arose predominantly from the external carotid artery. Large tumors had additional supply from the internal carotid and posterior circulation., Conclusion: Papillary endolymphatic sac tumors are destructive, hypervascular lesions that arise from the temporal bone retrolabyrinthine region. Increased signal intensity at unenhanced T1-weighted MR imaging is common and may help distinguish these lesions from more common, aggressive temporal bone tumors.

The authors present an unusual case of solitary intramedullary plasmacytoma. Awareness of this entity can facilitate appropriate surgical planning, which may include a limited biopsy prior to considering more extensive skull base surgery.

Purpose: To determine whether relative cortical thickness measurements of the precentral and postcentral gyri can be used to differentiate the central sulcus from adjacent cortical sulci., Methods: Turbo inversion-recovery MR imaging of the entire brain was done with scans parallel to the anterior commissure-posterior commissure line. Cortical thickness was measured in each hemisphere with a jeweler's eyepiece with 0.1-mm gradations. Three measurements were obtained perpendicular to the central, precentral, and superior frontal sulci, as determined by means of established anatomic methods. The ratios of cortical thickness on both sides of the central, precentral, and superior frontal sulci were calculated and compared., Results: The mean ratio of precentral/postcentral gyri was 1.64 for the right hemisphere and 1.53 for the left hemisphere. The mean cortical thickness ratios were as follows: 1.01 for the right hemisphere and 3.01 for the left hemisphere across the precentral sulcus, and 1.03 for the right hemisphere and 0.99 for the left hemisphere across the superior frontal sulcus., Conclusion: Cortical thickness measurements across the central sulcus provide a method for locating the primary motor (precentral gyri) and primary somatosensory (postcentral gyri) cortices. The higher mean cortical thickness ratio across the central sulcus corresponds with known cytoarchitectonic relationships.

The authors report an unusual case of venous infarction of the spinal cord associated with endoscopic sclerotherapy for esophageal varices. MR imaging findings included signal abnormalities and abnormal enhancement of the affected spinal cord and T-8 vertebral body. A review of the hemodynamic changes associated with portal hypertension and the normal venous drainage of the spinal cord is presented.

Radiation therapy of the brain, neck, and spine can be associated with radiation-induced changes that are increasingly evident radiologically. These changes affect the central nervous system (focal necrosis, diffuse white matter injury, atrophy, mineralizing microangiopathy, telangiectasia, optic neuropathy, large vessel vasculopathy), bone (fatty replacement of marrow, osteoradionecrosis, sinus inflammation), and superficial and deep soft tissues and include neoplasia. Focal necrosis, which most commonly occurs at the treatment site, is seen at computed tomography (CT) and magnetic resonance (MR) imaging as a ring-enhancing mass with edema and mass effect, findings similar to those of tumor recurrence. Diffuse white matter injury appears as hypoattenuating (at CT) or hyperintense (at MR imaging) small foci near the frontal or occipital horns or as a confluent band extending from the ventricles to the corticomedullary junction. Fatty replacement of marrow is the most common osseous complication seen on MR images. Osteoradionecrosis, which occurs most often in the mandible, appears as a focal lytic area at CT and with abnormal marrow signal and cortical destruction at MR imaging. The most common changes in the superficial soft tissues of the head and neck, edema and fibrosis, are seen radiologically as skin thickening and increased soft-tissue attenuation with stranding of subcutaneous fat. Meningioma, the most common radiation-induced CNS tumor, can be distinguished from spontaneous meningiomas on the basis of clinical characteristics (eg, presence of focal alopecia and scalp atrophy).

A 24-year-old man with hereditary multiple exostoses had numbness of the lower extremities and difficulty walking. CT displayed a calcified extradural mass lesion within the spinal canal at T-8 causing cord compression. MR imaging showed it to be contiguous with the upper endplate of T-8, suggesting the diagnosis of osteochondroma, a rare cause of cord compression, and distinguishing the lesion from a calcified disk fragment.

The preoperative diagnosis for an unusual skull base lesion was chordoma. The combination of imaging, pathologic, and surgical findings suggests the diagnosis of Rathke cyst.

The authors report the MR, CT, and pathologic findings in a case of invasive papillary cystadenoma originating in the endolymphatic sac and involving the temporal bone. This case illustrates characteristic imaging features of this lesion. The authors emphasize awareness of this entity with its aggressive temporal bone involvement as an aid to pathologic differential diagnosis.

Rhinolith, calcified concretion of a nidus within the nasal cavity, is a possible diagnosis for certain patients with densely mineralized lesions that appear benign and without bone destruction.

The authors report their experience with an infant presenting with an infected nasolacrimal duct mucocele, emphasizing correlation of clinical, CT, and surgical findings. CT is the imaging modality of choice to demonstrate the triad of 1) a cystic medial canthal mass, 2) dilatation of the nasolacrimal duct, and 3) a submucosal nasal cavity mass; findings which are diagnostic of this entity. A brief review of the relevant embryology is also presented.

Purpose: To address the clinical relevance of and optimal technique for 3-D CT imaging of facial trauma., Methods: Bioengineered cadaveric models were developed to enhance the concepts of LeFort. Diverse CT imaging techniques were applied to obtain optimal data sets for processing on various 3-D workstations. The fidelity of the 3-D reconstructions was determined by comparison with photographs of the cadaveric models. Optimized 3-D images were then used in conjunction with the initial 2-D data sets to assess whether additional accuracy was contributed by the 3-D images in the evaluation of modeled facial fractures., Results: Image definition was heavily dependent upon the specific 3-D reconstruction algorithm and the processor utilized. Orbital fractures were best imaged when 1- to 1.5-mm coronal sections were processed on an advanced 3-D workstation. The 3-D CT images resulted in additional accuracy in the 2-D CT evaluation of facial fractures in 29% of trials., Conclusions: We believe that bioengineered models of facial trauma--matched with appropriate CT scanning parameters--facilitate graphically reliable 3-D reconstructive imaging. 3-D reconstructions can improve accuracy in the 2-D CT evaluation of facial trauma.

A 3 1/2-year-old boy had thigh pain and a leg mass. Bone scanning demonstrated intense uptake within the involved femur, but no uptake within the soft tissues or evidence of metastatic spread. Radiographs and CT scanning showed a large soft tissue mass and periosteal reaction suggestive of Ewing's sarcoma. Following chemotherapy, the patient had an apparently good clinical response. However, bone scanning showed uptake that was more intense and extensive than it was before therapy. Plain films and CT showed that the uptake was evidence of soft tissue calcification and that the mass had shrunk. This is an unusual example of the flare response to therapy because the apparent progression of the disease on bone scanning was caused by extraskeletal uptake.

Some common legumes and weeds indigenous to peach orchards in South Carolina were tested in greenhouse experiments to determine their host suitability for Criconemella xenoplax. Legumes that were hosts for the nematode were dwarf English trefoil (Lotus corniculatus var. arvensis), big trefoil (L. uliginosis), birdsfoot trefoil (L. corniculatus), narrowleaf birdsfoot trefoil (L. tenuis), ball clover (Trifolium nigrescens), rose clover (T. hirtum), subterranean clover (T. subterraneum), striate lespedeza (Lespedeza striata), and partridge pea (Cassiafasciculata). Most nonleguminous plants tested did not support population increases, but small increases were observed on orchardgrass (Dactylis glomerata), broadleaf signalgrass (Brachiaria platyphylla), purslane (Portulaca oleracea), and Carolina geranium (Geranium carolinianum). Results indicate that leguminous plants probably should not be used as ground cover or rotation crops for plants that are injured by C. xenopax.

We examined the distribution of laminin, type IV collagen, and fibronectin in subepithelial vesicles of oral mucous membrane pemphigoid (MMP). Indirect immunofluorescence staining of these macromolecules was performed on 10 frozen biopsy specimens of oral MMP. We found type IV collagen in the connective tissue floor and laminin in the epithelial roof of these lesions. Our results suggest that the inflammatory injury in oral MMP may disrupt the interaction of laminin with type IV collagen in the basement membrane zone.

The current decline in the incidence of dental caries indicates that patients will retain most of their dentition. Reconstruction or regeneration of the entire attachment apparatus, including the periodontal ligament, cementum, and bone, is an attainable therapeutic goal. Clinical treatments designed to reattach connective tissue to exposed root surfaces commonly result in the formation of a long junctional epithelial attachment. This attachment is probably not an effective barrier to bacterial toxins and may allow recurrent pocket formation. To enhance reattachment of connective tissue, root-conditioning agents have been used but their clinical efficacy is questionable. Restoration of destroyed alveolar supporting bone by means of allogenic and autogenous bone-grafting materials has been recommended, but these procedures do not restore the cementum and PDL. Attempts to promote regeneration of the entire attachment apparatus have included clinical studies that used mechanical means to promote repopulation of affected root surfaces by periodontal ligament fibroblasts and prevent contact of epithelial or gingival connective tissue cells. Results thus far have been encouraging, but the practicality of these techniques may be limited. However, these studies have demonstrated that if only PDL cells contact the root surface during healing, a normal PDL can re-form. Dental follicle tissue is capable of inducing the formation of cementum-like structures and is clearly the cell population responsible for cementum and PDL formation. Recent research has demonstrated that the dental papilla probably shares the same inductive capabilities as the dental follicle.(ABSTRACT TRUNCATED AT 250 WORDS)

The release of endogenous glutamate and other primary amines from the lateral-line of Xenopus laevis was studied using an in vitro superfusion technique and high performance liquid chromatography. Potassium stimulation (50 mM KCl) applied to 60 or 120 lateral-line organs dissected from the skin and pooled in a perfusion chamber induced the release of glutamate and aspartate. The release of aspartate was smaller than that of glutamate and more variable. A variable release of two, as yet, unidentified substances was also detected. In low calcium (0.1 mM CaCl2), high magnesium (10 mM MgCl2) solution, 50 mM potassium failed to induce an increase in glutamate, aspartate and the two unknowns, suggesting they are released in a transmitter-like manner. The technique presents a new and simple method for studying transmitters in hair-cell systems. Although other interpretations are possible, the results are consistent with the hypothesis that glutamate is a hair-cell transmitter and suggest a potential role for other substances in the transduction process, perhaps as neuromodulators.

Abomasal engorgement was diagnosed in five Suffolk rams and one Suffolk ewe. All sheep had poor or no appetite for between seven days and five months duration. They were depressed, thin and weak. Rectal temperature and respiration rates were within the normal range. Pulse rate was increased (97.6 +/- 11.55/minute, mean +/- se). A distended abdomen was present and, or, a firm mass was ballotted or palpated in the lower right abdomen. Rumen motility was increased and contractions were strong. Laparotomy revealed enlarged abomasums in four sheep. Enlarged abomasums were found at necropsy in two sheep. Abomasal contents resembled rumen ingesta in character and odour. Removal of ingesta by abomasotomy produced temporary improvement in three rams for six to 12 weeks. All six sheep died or were euthanased.

This case report describes the effect of tricalcium phosphate implantation in the treatment of a chronic periapical abscess. Ceramic implant materials are biocompatible and are currently being used to restore alveolar bone loss resulting from periodontal disease, endodontic infections, and residual alveolar ridge resorption. However, use of such a material in this case led to persistent infection and additional bone destruction. Thus, the use of a ceramic implant material to accelerate periapical bone repair is not recommended in areas where a chronic bacterial infection is present.

This study prospectively evaluates hypercoagulable states in patients under 51 years of age undergoing lower extremity revascularization for ischemia and assesses early outcome after operation. Twenty patients whose ages range from 23 to 50 years (mean 40.8 years) were identified prospectively who underwent lower extremity revascularization and evaluation of hypercoagulability. Fifteen patients were male (75%), 10 were black (50%), six had hypertension (30%), and four were diabetic (20%). All but two were cigarette smokers (90%). Seven aortoiliac procedures and 13 infrainguinal procedures were performed. Six patients had one or more abnormalities of regulatory proteins (protein S deficiency, four; protein C deficiency, three; presence of lupus-like anticoagulant, three; plasminogen deficiency, two). Eight of 17 patients in whom platelet aggregation profiles were obtained showed increased reactivity (47%). Only 4 of 17 patients (24%) were normal when tested for all parameters. Arterial or graft thrombosis developed in four of the 20 patients within 30 days after operation. Hypercoagulability was found in all four patients whose revascularizations failed. A high incidence of hypercoagulable states was found in patients under 51 years of age with lower limb ischemia requiring revascularization. Hypercoagulability may have contributed to early postoperative thrombosis of the vascular procedure.