Dynamic contrast-enhanced perfusion processing for neuroradiologists: model-dependent analysis may not be necessary for determining recurrent high-grade glioma versus treatment effect.

BACKGROUND AND PURPOSE: Dynamic contrast-enhanced perfusion MR imaging has proved useful in determining whether a contrast-enhancing lesion is secondary to recurrent glial tumor or is treatment-related. In this article, we explore the best method for dynamic contrast-enhanced data analysis. MATERIALS AND METHODS: We retrospectively reviewed 24 patients who met the following conditions: 1) had at least an initial treatment of a glioma, 2) underwent a half-dose contrast agent (0.05-mmol/kg) diagnostic-quality dynamic contrast-enhanced perfusion study for an enhancing lesion, and 3) had a diagnosis by pathology within 30 days of imaging. The dynamic contrast-enhanced data were processed by using model-dependent analysis (nordicICE) using a 2-compartment model and model-independent signal intensity with time. Multiple methods of determining the vascular input function and numerous perfusion parameters were tested in comparison with a pathologic diagnosis. RESULTS: The best accuracy (88%) with good correlation compared with pathology (P = .005) was obtained by using a novel, model-independent signal-intensity measurement derived from a brief integration beginning after the initial washout and by using the vascular input function from the superior sagittal sinus for normalization. Modeled parameters, such as mean endothelial transfer constant > 0.05 minutes(-1), correlated (P = .002) but did not reach a diagnostic accuracy equivalent to the model-independent parameter. CONCLUSIONS: A novel model-independent dynamic contrast-enhanced analysis method showed diagnostic equivalency to more complex model-dependent methods. Having a brief integration after the first pass of contrast may diminish the effects of partial volume macroscopic vessels and slow progressive enhancement characteristic of necrosis. The simple modeling is technique- and observer-dependent but is less time-consuming.

CT imaging correlates of genomic expression for oral cavity squamous cell carcinoma.

BACKGROUND AND PURPOSE: Imaging correlates of genetic expression have been found for prognostic and predictive biomarkers of some malignant diseases, including breast and brain tumors. This study tests the hypothesis that imaging findings correlate with relevant genomic biomarkers in oral cavity squamous cell carcinoma. MATERIALS AND METHODS: Surplus frozen tissue from 27 untreated patients with oral cavity squamous cell carcinoma who underwent preoperative CT imaging was analyzed for gene expression. A team of neuroradiologists blinded to the genomic analysis results reviewed an extensive list of CT findings. The imaging correlated with genomic expression for cyclin D1, angiogenesis-related genes (vascular endothelial growth factor receptors and ligands), which relate to enhancement on the basis of other tumor types; and epidermal growth factor receptor, which may relate to proliferation and mass effect. RESULTS: Expression of vascular endothelial growth factor receptors 1 and 2 correlated with the enhancement of the primary tumor (P = .018 and P = .025, respectively), whereas the epidermal growth factor receptor correlated with mass effect (P = .03). Other exploratory correlations included epidermal growth factor receptor to perineural invasion (P = .05), and certain vascular endothelial growth factor receptors and ligands to mass effect (P = .03) and increased (P = .01) or decreased (P = .02) primary tumor size. CONCLUSIONS: We report that CT imaging correlates with gene expression in untreated oral cavity squamous cell carcinoma. Enhancement of the primary tumor and degree of mass effect correlate with relevant genomic biomarkers, which are also potential drug targets. Eventually, treatment decisions may be aided by combining imaging findings into meaningful phenotypes that relate directly to genomic biomarkers.

Improving imaging diagnosis of persistent nodal metastases after definitive therapy for oropharyngeal carcinoma: specific signs for CT and best performance of combined criteria.

BACKGROUND AND PURPOSE: Criteria for detection of persistent nodal metastases in treated oropharyngeal tumors are sensitive but nonspecific, leading to unnecessary nodal dissections. Developing specific imaging criteria for persistent nodal metastases could improve diagnosis while decreasing patient morbidity. MATERIALS AND METHODS: Patients with oropharyngeal squamous cell carcinoma with nodal metastases treated by definitive radiation therapy and subsequent nodal dissection were retrospectively evaluated. One hundred thirty-eight patients had pre- and posttherapy contrast-enhanced CTs evaluated by radiologists blinded to the status of pathologically proved hemineck persistent nodal metastases. Composite scoring criteria for CT, combined from individual parameters, were compared with radiologists' opinions, previous multiparameter criteria, and outcome data. RESULTS: New low-attenuation areas and a lack of size change (<20% cross sectional area) were both highly specific for persistent nodal metastases (99%; P = .0004). Extranodal disease on pretherapy imaging was moderately specific (86%; P = .001). The CSC correctly placed 29 patients in a low-risk category compared with 14 by previously reported criteria and radiologist reports. With good second-rater reliability, the CSC cutoff values stratified patients at highest risk of persistent nodal metastases, thereby improving specificity while maintaining sensitivity. CONCLUSIONS: Comparing pre- and posttherapy examinations improves specificity by discriminating focal findings and size change compared with a single time point. The CSC can categorize the risk of persistent nodal metastases more accurately than previous CT methods. This finding has the potential to improve resource use and reduce surgical morbidity.

Preoperative grip strength measurement and duration of hospital stay in patients undergoing total hip and knee arthroplasty.

PURPOSE: This study explored whether a relationship exists between preoperative pinch and power grip strength, and length of hospital stay in patients undergoing hip and knee arthroplasty at a busy UK hospital. We investigated whether handgrip dynamometry could be used preoperatively to identify patients at greater risk of longer inpatient stays. This would allow focussed intervention preoperatively and facilitate predictors of length of stay postoperatively. METHODS: One hundred and sixty-four patients (64 male, 100 female) undergoing lower limb arthroplasty (83 total knee replacement, 81 total hip replacement) were assessed in pre-admission clinic. Average measurements of pinch grip, power grip and grip endurance were taken from each patient using the Jamar hydraulic dynamometer (Jamar, USA). Duration of inpatient stay of each patient was recorded. RESULTS: Average duration of hospital stay was 9.4 days. Both average pinch grip strength and average power grip strength had a significant negative correlation with duration of inpatient stay. Those patients with a pinch grip strength less than 6.3 kg remained an inpatient for an average of 2 days longer than those with a pinch grip greater than 6.3 kg. CONCLUSIONS: This simple test may be highly beneficial preoperatively in identifying those patients likely to require longer inpatient stays and therefore those who would benefit from early nutritional intervention and focussed physiotherapy. It may also facilitate predictors of length of stay postoperatively. We believe this may effect significant cost reductions in the NHS.

The pattern of ankle fractures sustained by outdoor activities at the Snowdonia National Park, North Wales, United Kingdom.

OBJECTIVE: The aim of this study was to review the pattern of ankle fractures sustained by patients brought to the Emergency Department at Ysbyty Gwynedd from The Snowdonia National Park. MATERIALS AND METHODS: The study group included all patients with ankle fractures on the mountain medicine database between March 2004 and December 2006. The presence of talar shift and comminution of the medial malleolus was noted. The pattern of fractures were analysed and compared with the literature. Radiographs were obtained for 20 casualties. RESULTS: 70% of these were injured whilst hill walking. Open fractures represented 12% of injuries. 75% of fractures required operative fixation. Weber B injuries were the commonest followed by Weber C and A. Talar shift was seen in 80% of the cases and 45% showed comminution of the medial malleolus. CONCLUSIONS: In our case series we observed a high proportion of open and unstable ankle fractures, with the majority treated by operative fixation. The high rate of comminution of the medial malleolus has previously not been reported in the literature and has the potential of making operative fixation technically difficult. Encouraging the use of walking poles particularly at the time of descending may help to reduce the incidence of ankle fractures in hill walkers.

The importance of surgical education in the accuracy of implant placement during hip fracture fixation.

BACKGROUND: Studies have found that tip apex distance (TAD) is the strongest independent predictor of lag screw cut-out following hip fracture fixation. The objective of this study was to understand the importance of introducing the concept of TAD to surgeons. The null hypothesis was that there were no differences between fractures fixed before awareness of TAD compared with fractures fixed after awareness of TAD. MATERIALS AND METHODS: This study involved assessing 75 consecutive radiographs retrospectively (before introduction of "tip apex distance" to surgeons) and 83 consecutive radiographs prospectively (after introduction of "tip apex distance" to surgeons). Radiographs were measured using a radiograph digitizer and software. RESULTS: Average TAD in radiographs measured retrospectively was 22.6 mm compared with 9.7 mm in radiographs analysed prospectively (P

Improving fat-suppressed T2-weighted imaging of the head and neck with 2 fast spin-echo dixon techniques: initial experiences.

Two modified fast spin-echo (FSE) techniques (a 2-point and a single-scan triple-echo Dixon) were used for T2-weighted imaging of the head and neck in 7 patients along with conventional FSE with fat saturation. Both Dixon techniques provided consistent and more uniform fat suppression (FS) than conventional FSE. The 2-point Dixon technique was noted to be more susceptible to motion artifacts. The triple-echo Dixon technique offered the best scan time efficiency and overall image quality.

The shrinking thyroid: how does thyroid size change following radiation therapy for laryngeal cancer?

BACKGROUND AND PURPOSE: External beam radiation therapy (XRT) for head and neck cancer is known to induce hypothyroidism and cause morphologic changes in the thyroid gland. This retrospective study investigates change in the size of the thyroid gland detectable by CT after XRT for laryngeal cancer. MATERIALS AND METHODS: The measured width of the thyroid lobes in 61 patients treated nonsurgically with XRT for laryngeal cancer between 2000 and 2003 on posttherapy CT was compared with that on pretherapy CT. Absolute and percentage changes in measured thyroid width following XRT were analyzed according to chemotherapy administration and posttherapy thyroid function. RESULTS: Eighty-five percent (52/61) of patients had a decrease in the width of the thyroid gland. The average change in width measuring -4.7 mm and -13.8% (SD, 5.7 mm and 19.9%) occurred at an average of 758 days following completion of XRT (mean, 402-1534 days) and was significant (P = .002). Average change in width between hypothyroid patients (n = 19, -6.1 mm and -20.0% change) and euthyroid patients (n = 42, -4.1 mm and -11.1% change) was not significant (P = .20 absolute change and P = .11 percentage change). The average change in width between patients receiving chemotherapy (n = 31, -5.5 mm and -16.1% change) and patients not receiving chemotherapy (n = 30, -3.9 mm and -11.5% change) was not significant (P = .26 absolute change and P = .37 for percentage change). CONCLUSIONS: Most nonsurgical patients receiving XRT for laryngeal cancer have a significant decrease in the width of their thyroid glands detected on CT. The average change in the size of the thyroid gland does not differ when development of hypothyroidism or chemotherapy administration are considered.

Multidetector CT-Guided Lumbar Puncture in Patients with Cancer.

SUMMARY: Lumbar puncture can be performed for therapeutic purposes, to instill intrathecal chemotherapy for leptomeningeal cancer treatment or prophylaxis. This technique is generally performed blindly or under fluoroscopic guidance. However, in certain situations, lumbar puncture using multidetector CT (MDCT)-guided imaging may be beneficial, when other options have been exhausted or depending on the requirements of the performing radiologist's institution. The purpose of this article is to describe the technique and to evaluate outcomes of MDCT-guided lumber puncture for diagnostic and therapeutic purposes in patients with cancer. We conclude that MDCT-guided lumbar puncture is an effective and safe guiding modality for thecal sac access in patients with cancer, particularly where other methods of intrathecal access have failed.

Parotid gland oncocytosis: CT findings with histopathologic correlation.

Oncocytic neoplasms result from metabolically altered cells that accumulate abundant mitochondria within their cytoplasm by oncocytic metaplasia. In this report, the CT findings are described and correlated with the histopathologic features of a case of oncocytoma involving the parotid gland that arose in a background of nodular oncocytic hyperplasia. When imaging demonstrates multiple small nodules in the parotid gland with a large, solid, or cystic mass, the diagnosis of oncocytic neoplasia should be considered.

Dynamic posterior stabilization of shoulder hemiarthroplasty in long-standing neglected posterior dislocation of the glenohumeral joint.

Posterior dislocations of the shoulder are rare. They account for less than 3% of all shoulder dislocations. The treatment of neglected bilateral posterior dislocation of the shoulder is controversial. We present a novel operative technique to stabilize a shoulder hemiarthroplasty that we used in the treatment of a chronic posterior dislocation of a shoulder with an acute four-part fracture of the proximal humerus.

Anatomical study comparing the thickness of the volar and dorsal cortex of cadaveric adult distal radii using digital photography.

INTRODUCTION: Dorsally displaced fractures of the distal radius fractures are one of the commonest in day-to-day practice. There is still no consensus among surgeons regarding the suitability of using volar or the dorsal cortex as basis for internal fixation for dorsally displaced fractures. BACKGROUND: We report an anatomical study, which compares the thickness of the volar and dorsal cortices of cadaveric adult radii using digital photography. RESULTS: Results of this study show that the volar cortex was statistically, significantly thicker than the dorsal cortex. We believe that the volar cortex may behave as the calcar of the distal radius and hence internal fixation devices applied to the volar cortex may provide a more stable internal fixation compared to those based on the dorsal cortex.

Textiloma (gossypiboma) mimicking recurrent intracranial tumor.

CONTEXT: Resorbable substances used to achieve hemostasis during neurosurgical procedures comprise 3 principal classes based on chemical composition: (1) gelatin sponge, (2) oxidized cellulose, and (3) microfibrillar collagen. Nonresorbable hemostatic aides include various forms of cotton and rayon-based hemostats (cottonoids and kites). Resorbable and nonresorbable hemostatic agents have been reported to cause symptomatic mass lesions, most commonly following intra-abdominal surgery. Histologic examination typically shows a core of degenerating hemostatic agent surrounded by an inflammatory reaction. Each agent exhibits distinctive morphologic features that often permit specific identification. Hemostat-associated mass lesions have been variously referred to as textilomas, gossypibomas, gauzomas, or muslinomas. OBJECTIVES: The aims of this study were to (1) identify cases of histologically proven cases of textiloma in neurosurgical operations, (2) characterize the specific hemostatic agent associated with textiloma formation, and (3) characterize the preoperative magnetic resonance imaging appearance of textiloma. DESIGN: Cases in which a textiloma constituted the sole finding on repeat surgery for recurrent brain tumor, or was a clinically significant component of a radiologically identified mass lesion together with residual tumor, constituted the study set. RESULTS: Five textilomas were identified and evaluated. The primary neoplasm was different in each case and included pituitary adenoma, tanycytic ependymoma, anaplastic astrocytoma, gliosarcoma, and oligodendroglioma. In all cases, preoperative magnetic resonance imaging suggested recurrent tumor. Textilomas included all categories of resorbable hemostatic agent. Other foreign bodies were present in some cases; the origin of these foreign bodies was traced to fibers shed from nonresorbable hemostatic material placed temporarily during surgery and removed before closure (cottonoids and kites). Inflammatory reactions included giant cells, granulomas, and fibroblastic proliferation. Microfibrillar collagen (Avitene) textilomas were associated with a striking eosinophil infiltration that was not seen with any other hemostatic agent. CONCLUSIONS: Hemostatic agents may produce clinically symptomatic, radiologically apparent mass lesions. When considering a mass lesion arising after intracranial surgery, the differential diagnosis should include textiloma along with recurrent tumor and radiation necrosis.

Medial meniscus interposition in proximal tibial epiphyseal fracture: a case report and review of the literature.

Proximal tibial fractures are rare in children, and most are treated conservatively. We report a case of a minimally displaced proximal tibial epiphyseal injury (Salter-Harris type III) in an 11-year-old child. We initially thought to treat this fracture conservatively, but the presence of massive haemarthrosis and considerable pain made us choose arthroscopy under general anaesthetic. During examination under anesthesia no instability could be detected, but the knee was locked in 5 degrees of flexion. On screening the fracture was not reducible anatomically. At arthroscopy the medial meniscus was not visualised as it was displaced into the fracture site. A small medial arthrotomy showed the meniscus trapped in the fracture site without any avulsion in the anterior or posterior horns. The fracture easily reduced once the meniscus was levered out. The importance of this injury is the fact that it could have been easily missed and would have led to serious functional deficit of the knee joint. We present radiographs and intra-operative pictures of this interesting injury.

Malignant gliomas: MR imaging spectrum of radiation therapy- and chemotherapy-induced necrosis of the brain after treatment.

PURPOSE: To describe both the common and less frequently encountered magnetic resonance (MR) imaging features of radiation therapy- and chemotherapy-induced brain injury, with particular emphasis on radiation necrosis. MATERIALS AND METHODS: A cohort of 148 adult patients underwent surgical resection of malignant brain (glial) tumors and were subsequently entered into a research protocol that consisted of accelerated radiation therapy with carboplatin followed by chemotherapy with procarbazine, lomustine, and vincristine. Patients typically underwent sequential MR imaging at 6-8-week intervals during the 1st year and at 3-6-month intervals during subsequent years. In all patients, histopathologic confirmation of lesion composition was performed by board-certified neuropathologists. RESULTS: The patients exhibited different types of MR imaging-detected abnormalities of the brain: pure radiation necrosis in 20 patients, a mixture of predominantly radiation necrosis with limited recurrent and/or residual tumor (less than 20% of resected tissue) in 16 patients, radiation necrosis of the cranial nerves and/or their pathways in two patients, radiation-induced enhancement of the white matter in 52 patients, and radiation-induced enhancement of the cortex in nine patients. CONCLUSION: The frequent diagnostic dilemma of recurrent neoplasm versus radiation necrosis is addressed in this study through a description of the varying spatial and temporal patterns of radiation necrosis at MR imaging.

Magnetic resonance imaging of benign spinal lesions simulating metastasis: role of diffusion-weighted imaging.

In an attempt to avoid unnecessary therapy, this article demonstrates benign vertebral body lesions that mimic metastatic disease in cancer patients with back pain. The magnetic resonance imaging features that aid in differential diagnosis are demonstrated. In addition, the value of diffusion-weighted spinal imaging to further aid in distinguishing benign from malignant disease is described.

Imaging and clinical spectrum of rhabdomyosarcoma in children.

We retrospectively analyzed the MRI findings of rhabdomyosarcoma (RMSA) in 23 patients to evaluate its role in staging and management. Heterogeneous signal abnormalities were noted in the sarcoma lesions with significant contrast enhancement. Seven head and neck cases showed direct bone invasion and destruction; only one had distant bony metastasis. Metastasis was noted in the lymph nodes, lung, bone, abdominoperitoneum, and head and neck soft tissue. MRI findings of RMSA are most helpful in staging and assessing therapeutic response.

A second look at unenhanced spinal magnetic resonance imaging of malignant leptomeningeal disease.

The purpose of this study is to evaluate the use of unenhanced magnetic resonance (MR) imaging in identifying malignant leptomeningeal disease (MLD). Included in this study were fifty patients with evidence of leptomeningeal enhancement on post-gadolinium MR images and with cytological confirmation of MLD. Unenhanced, T1-weighted spin-echo (SE) MR images of the spine were analyzed for loss of cerebrospinal fluid (CSF) clarity, poor definition of the conus medullaris, thickened and clumped nerve roots, and nodules. Patterns of leptomeningeal enhancement on post-gadolinium, T1-weighted SE images were noted. Findings of MLD on unenhanced MR images were observed in 41 (85%) of 48 studies of the lumbar spine, 10 (50%) of 20 studies of the thoracic spine, and two (33%) of six studies of the cervical spine. In the lumbar spine, thickened and clumped nerve roots, poor definition of the conus medullaris, loss of CSF clarity, and nodules were observed with decreasing frequency. The signs of MLD on unenhanced images of the cervicothoracic spine included nodules and clouding of CSF. Patterns of leptomeningeal enhancement included linear, linear/nodular, nodular, enhancement of nerve roots, and stacking, with tumor filling the lumbosacral canal. Findings of MLD were present on 73% of the unenhanced MR images of the spine. Recognition of MLD on unenhanced MR images can guide the appropriate work-up and therapeutic approach.

Successful treatment of progressive multifocal leukoencephalopathy with low-dose interleukin-2.

A patient with low-grade lymphoma presented 8 months after autologous marrow transplantation with dizziness, aphasia and hemiparesis. Magnetic resonance imaging (MRI) showed an abnormal T2 signal in the frontoparietal region unilaterally. Biopsy of the area demonstrated progressive multifocal leukoencephalopathy positive for JC virus and p53. Treatment with interleukin-2 at 0.5 MU/m2/day i.v. continuous infusion resulted in near complete resolution of symptoms and MRI abnormalities. The absolute number of CD3+CD4+ and CD3-CD56+ cells in the peripheral blood also increased, and the CD4/CD8 ratio normalized. She remains free of evidence of progressive multifocal leukoencephalopathy 1 year off therapy.

Intracranial metastatic melanoma: correlation between MR imaging characteristics and melanin content.

OBJECTIVE: Preliminary reports based on limited numbers of cases have proposed that specific MR imaging patterns may permit a distinction between melanotic and amelanotic brain metastases in melanoma patients. The purpose of this study was to test this hypothesis by categorizing MR images obtained from a large series of patients and correlating the results with the percentage of melanin-containing cells in surgically resected metastases. SUBJECTS AND METHODS: The MR images of 30 patients with histologically proven intracerebral melanoma were reviewed retrospectively. Precontrast MR images were obtained with T1-weighted spin-echo sequences in axial and sagittal sections and with proton density-weighted and T2-weighted sequences in axial sections. After IV injection of gadopentetate dimeglumine (0.1 mmol/kg of body weight), T1-weighted images were obtained in axial and coronal sections. All patients had undergone gross total resection of the evaluated lesions. MR images of the metastases were reviewed and sorted into four groups on the basis of putative patterns: (1) melanotic pattern--hyperintense in relation to cortex on T1-weighted images, hypointense in relation to cortex on T2-weighted images, and isointense or hyperintense in relation to cortex on proton density-weighted images; (2) amelanotic pattern--hypointense or isointense in relation to cortex on T1-weighted images and hyperintense or isointense in relation to cortex on T2-weighted and proton density-weighted images; (3) indeterminate, or mixed, pattern--MR imaging characteristics that did not conform to those of one of the first two categories; and (4) hematoma pattern--MR imaging features that exhibited only hematoma characteristics. Tissue sections from all evaluated lesions were independently reviewed by a neuropathologist (G.N.F.), and the percentage of melanin-containing tumor cells in each resected metastatic lesion was estimated. The MR imaging data and histologic data were then compared to assess the predictive value of the MR imaging patterns. RESULTS: Forty-two metastatic lesions were identified and categorized by MR imaging pattern as follows: 10 melanotic, 11 indeterminate (mixed), 16 amelanotic, and five hematoma. Correlation with histologic findings revealed that a majority (7/10) of lesions that exhibited a melanotic MR imaging pattern had more than 10% melanin-containing cells, over half (9/16) of lesions that exhibited an amelanotic MR imaging pattern contained histologically identifiable melanin (but always in less than 10% of cells), and lesions that exhibited a mixed MR imaging pattern were either amelanotic or contained less than 10% melanotic cells. Conversely, a majority of lesions containing more than 10% melanotic cells (7/8) demonstrated the typical melanotic MR imaging pattern, lesions with less than 10% melanin-containing cells exhibited a variety of MR imaging patterns, and only about half of patients with amelanotic lesions (6/13) showed the characteristic amelanotic MR imaging pattern. For five lesions, potentially informative imaging data on melanin content was obscured by histologically documented hematoma formation. CONCLUSION: Only a minority of melanoma metastases have the anticipated MR imaging findings of melanotic melanoma, which consist of high signal intensity relative to that of cortex on T1-weighted images and low signal intensity relative to that of cortex on T2-weighted images. Of tumors that do exhibit this melanotic pattern, the majority have more than 10% melanin-containing cells. The putative MR imaging pattern for amelanotic melanoma is nonspecific, as over half of tumors with this pattern contain melanin.