Glenoid notch MRI findings do not predict normal variants of the anterior and superior labrum.

AIM: To determine (1) the relationship of a glenoid notch to the presence of a normal labral variant in the anterior-superior glenoid labrum; (2) the inter- and intra-observer reliability of recognising a glenoid notch; and (3) whether magnetic resonance arthrography (MRA) is more reliable than non-contrast magnetic resonance imaging (MRI) in visualising a glenoid notch. MATERIALS AND METHODS: From 1995 through 2010, 104 patients underwent MRI or MRA before diagnostic shoulder arthroscopy by the senior author. Five blinded musculoskeletal radiologists independently read the images twice to evaluate for the presence or absence of a glenoid notch. Fifty-nine (57%) patients had normal anterior-superior labral variants. The authors calculated the relationship of the readings to the arthroscopically determined presence or absence of a normal labral variant and the reading's diagnostic performance and rater reliability. RESULTS: On average, 38% (range 9-65%) of the glenoid scans were read as notched. The sensitivity, specificity, positive predictive value, and negative predictive value of the notch relative to the presence of a normal variant were 43.1%, 71.2%, 70.2%, and 48% versus 44.3%, 77.5%, 79.4%, and 56.1% for MRI and MRA, respectively. The overall average intra-observer κ-values were 0.438 (range 0.203-0.555) and 0.346 (range -0.102 to 0.570) for MRI and MRA, respectively. The average interobserver intra-class correlation coefficient reliability values were 0.730 (range 0.693-0.760) and 0.614 (range 0.566-0.662) for MRI and MRA, respectively. CONCLUSIONS: A notched glenoid on MRI lacks sufficient diagnostic performance and rater reliability for the clinical detection and prediction of normal anterior-superior labral variants.

Characterization of peripheral nerve sheath tumors with 3T proton MR spectroscopy.

BACKGROUND AND PURPOSE: The characterization of peripheral nerve sheath tumors is challenging. The purpose here was to investigate the diagnostic value of quantitative proton MR spectroscopy at 3T for the characterization of peripheral nerve sheath tumors as benign or malignant, compared with PET. MATERIALS AND METHODS: Twenty participants with 24 peripheral nerve sheath tumors underwent MR spectroscopy by use of a point-resolved sequence (TE, 135 ms). Six voxels were placed in 4 histologically proven malignant peripheral nerve sheath tumors and 22 voxels in 20 benign peripheral nerve sheath tumors (9 histologically proven, 11 with documented stability). The presence or absence of a trimethylamine signal was evaluated, the trimethylamine concentration estimated by use of phantom replacement methodology, and the trimethylamine fraction relative to Cr measured. MR spectroscopy results for benign and malignant peripheral nerve sheath tumors were compared by use of a Mann-Whitney test, and concordance or discordance with PET findings was recorded. RESULTS: In all malignant tumors and in 9 of 18 benign peripheral nerve sheath tumors, a trimethylamine peak was detected, offering the presence of trimethylamine as a sensitive (100%), but not specific (50%), marker of malignant disease. Trimethylamine concentrations (2.2 ± 2.8 vs 6.6 ± 5.8 institutional units; P < .049) and the trimethylamine fraction (27 ± 42 vs 88 ± 22%; P < .012) were lower in benign than malignant peripheral nerve sheath tumors. A trimethylamine fraction threshold of 50% resulted in 100% sensitivity (95% CI, 58.0%-100%) and 72.2% (95% CI, 59.5%-75%) specificity for distinguishing benign from malignant disease. MR spectroscopy and PET results were concordant in 12 of 16 cases, (2 false-positive results for MR spectroscopy and PET each). CONCLUSIONS: Quantitative measurement of trimethylamine concentration by use of MR spectroscopy is feasible in peripheral nerve sheath tumors and shows promise as a method for the differentiation of benign and malignant lesions. Trimethylamine presence within a peripheral nerve sheath tumor is a sensitive marker of malignant disease, but quantitative measurement of trimethylamine content is required to improve specificity.

High-resolution 3T MR neurography of the brachial plexus and its branches, with emphasis on 3D imaging.

With advancement in 3D imaging, better fat-suppression techniques, and superior coil designs for MR imaging and the increasing availability and use of 3T magnets, the visualization of the complexity of the brachial plexus has become facile. The relevant imaging findings are described for normal and pathologic conditions of the brachial plexus. These radiologic findings are supported by clinical and/or EMG/surgical data, and corresponding high-resolution MR neurography images are illustrated. Because the brachial plexus can be affected by a plethora of pathologies, resulting in often serious and disabling complications, a better radiologic insight has great potential in aiding physicians in rendering superior services to patients.

Peripheral nerve surgery: the role of high-resolution MR neurography.

High-resolution MRN is becoming increasingly available due to recent technical advancements, including higher magnetic field strengths (eg, 3T), 3D image acquisition, evolution of novel fat-suppression methods, and improved coil design. This review describes the MRN techniques for obtaining high-quality images of the peripheral nerves and their small branches and imaging findings in normal as well as injured nerves with relevant intraoperative correlations. Various microsurgical techniques in peripheral nerves, such as neurolysis, nerve repairs by using nerve grafts, and conduits are discussed, and MRN findings of surgically treated nerves are demonstrated.

The role of magnetic resonance imaging in the diagnostic evaluation of malignant peripheral nerve sheath tumors.

BACKGROUND AND AIMS: Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of mortality in patients with neurofibromatosis type-1 (NF1)); however, they may also arise sporadically. Differences in magnetic resonance imaging (MRI) features between MPNSTs arising in NF1 subjects versus non-NF1 subjects have not been studied before. The accuracy of MRI in distinguishing MPNSTs from benign peripheral nerve sheath tumors (BPNSTs) has also been debated. The objective of this study was to determine the potential differentiating MRI features between (a) NF1-related and non-NF1-related MPNSTs and (b) MPNSTs and BPNSTs. MATERIALS AND METHODS: We retrospectively evaluated the MRI studies of 21 patients (12 NF1 subjects and nine non-NF1 subjects) with MPNSTs and 35 patients with BPNSTs. In all studies, the lesions were assessed in terms of size, margins, T1 and T2 signal characteristics, internal architecture, pattern of contrast enhancement, invasion of adjacent structures and necrosis/cystic degeneration as well as for the presence of tail-, target- and split-fat signs. RESULTS: MPNSTs of NF1 subjects occurred at an earlier age and displayed a higher incidence of necrosis/cystic degeneration compared with MPNSTs of non-NF1 subjects. Compared with BPNSTs, MPNSTs were significantly larger at the time of diagnosis and demonstrated a higher incidence of ill-defined margins (specificity 91%, sensitivity 52%) and invasion of adjacent structures (specificity 100%, sensitivity 43%). CONCLUSIONS: Differences exist between NF1-related and non-NF1-related MPNSTs regarding the age of occurrence and MRI appearance. In the MRI evaluation of peripheral nerve sheath tumors, the presence of ill-defined tumor margins and/or invasion of adjacent structures are highly specific for malignancy.

The value of transcranial Doppler sonography with a transorbital approach in the confirmation of cerebral circulatory arrest.

OBJECTIVE: Transcranial Doppler sonography (TCD) provides accurate confirmation of cerebral circulatory arrest (CCA) in brain death (BD), but is not feasible in patients with absent temporal bone windows. We added the transorbital approach in the TCD protocol for the diagnosis of CCA and compared findings with angiography. Furthermore, we evaluated whether reporting the angiographic and sonographic confirmation of CCA to relatives of brain-dead patients improves their comprehension and satisfaction with the medical information. PATIENTS AND METHODS: Eighty-two clinically brain-dead patients underwent 4-vessel angiography, TCD of the basilar and middle cerebral arteries, and transorbital Doppler sonography (TOD) of the internal carotid arteries. Relatives were randomly allocated to 41 in whom BD was presented as a clinical diagnosis (group A) and to 41 in whom BD was presented as a clinical diagnosis confirmed by TCD and angiography (group B). Comprehension and satisfaction of the relatives were assessed using an interview and a questionnaire. RESULTS: Both angiography and TCD verified CCA in all cases (k = 1). In 11 patients with failure of the transtemporal approach, CCA was confirmed by the transorbital recordings. The addition of TOD enabled 15.5% more cases of CCA to be diagnosed by TCD. Group B exhibited improved comprehension and satisfaction rates (P < .05). CONCLUSIONS: The addition of TOD increases the efficacy of TCD in confirming CCA in BD. Reporting confirmation of CCA to families of brain-dead patients may improve their comprehension and satisfaction with the provided medical information.

Optic nerve sonography: a new window for the non-invasive evaluation of intracranial pressure in brain injury.

Enlargement of the optic nerve sheath has been described in patients with raised intracranial pressure (ICP), thereby serving as one of its indicators. Optic nerve sonography offers rapid bedside assessment of the optic nerve sheath diameter and has recently been introduced for the non-invasive detection of raised ICP, particularly in patients with severe brain injury. This review explains the pathophysiology of optic nerve sheath enlargement as a result of intracranial hypertension, describes the technique and clinical use of optic nerve sonography, and summarises the studies which have tested this modality in the non-invasive evaluation of ICP.

Secondary involvement of breast with non-Hodgkin's lymphoma in a patient with HIV infection -- case report.

Secondary lymphoma of the breast is a rare entity in patients with non-Hodgkin's lymphoma (NHL). HIV infection is associated with an increased risk for developing NHL, however lymphomatous involvement of the breast in AIDS patients has rarely been reported. We present the case of a 33-year-old HIV-infected female patient with diffuse NHL who presented with a unilateral breast mass. Histologic examination of the biopsy specimen revealed a highly-malignant diffuse large B-cell lymphoma.

Transorbital sonographic monitoring of optic nerve diameter in patients with severe brain injury.

OBJECTIVE: We investigated whether alterations in the optic nerve diameter (OND) correlated with brain computed tomography (CT) imaging results among patients with brain injury and whether monitoring of OND could predict brain death. PATIENTS AND METHODS: We enrolled 54 patients with brain injury (Glasgow Coma Scale < 8) and 53 controls. OND measurements were performed 3 mm posterior to the papillae by means of transorbital sonography. The severity of the injury was classified according to a semiquantitative CT neuroimaging scale (1 to 4). All patients underwent 3 repeated evaluations of OND combined with synchronous CT scans. RESULTS: Twenty-two patients progressed to brain death, while 32 patients showed gradual clinical improvement. Upon admission, the patients showed significantly increased OND (4.84 +/- 1.2 mm) compared with the controls (3.49 +/- 1.1 mm; P < .001). The median intraobserver variation of OND was 0.2 mm (95% confidence intervals [CI]: 0.1-0.7). The median interobserver variation of OND was 0.3 mm (95% CI: 0.1-0.9). Alterations in the OND were significantly correlated with the neuroimaging scale on 3 repeated evaluations: r = .65, r = .70, and r = .73 (all P < .001). An OND greater than 5.9 mm (specificity = 65% and sensitivity = 74%; P < .01) and a 2.5 mm increased OND between repeated measurements (specificity = 70% and sensitivity = 81%; P < .01) were associated with a poor prognosis. CONCLUSIONS: Alterations in OND strongly correlated with neuroimaging results among patients with brain injury. However, monitoring of OND exhibited a low predictive value for brain death.