Clinical significance of the tail-like pattern in soft-tissue sarcomas on magnetic resonance imaging.

BACKGROUND: An infiltrating abnormal signal around soft-tissue tumors along the fascial, neurovascular, or musculature plane on magnetic resonance imaging (T2-weighted, gadolinium-enhanced T1-weighted, or short-tau inversion recovery) is recognized as the "tail-like pattern". The tail-like pattern was intensively analyzed in myxofibrosarcoma, but not in other sarcomas. We aimed to answer some key questions about the tail-like pattern such as its incidence and effect on oncological outcomes. METHODS: The presence of the tail-like pattern in 114 soft-tissue sarcomas was evaluated on T2-weighted images or gadolinium-enhanced T1-weighted images, or both. We analyzed the incidence of the tail-like pattern in all cases and in specific histological subtypes. We also assessed the clinical backgrounds of the presence of the tail-like pattern and its impact on achieving adequate surgical margins and oncological outcomes, including local recurrence and overall survival. RESULTS: The tail-like pattern was detected in 50% of cases. The tail-like pattern was most common in myxofibrosarcoma and undifferentiated pleomorphic sarcoma, and less common in low-grade sarcomas. Trans-compartmental invasion of the tumor and high-grade malignancy were common clinical backgrounds for the presence of the tail-like pattern. The presence of the tail-like pattern significantly inhibits the achievement of preoperatively planned surgical margins despite planning the margins outside the tail-like pattern area. The tail-like pattern was an independent risk factor for local recurrence. The pattern was not an independent risk factor for worse overall survival, although it was a risk factor in univariate analysis. CONCLUSION: The tail-like pattern is clinically significant in myxofibrosarcomas and other sarcomas with respect to the preoperative evaluation of malignancy by magnetic resonance imaging, and negatively affects successful resection and oncological outcomes. A more sophisticated modality for the evaluation and clinical management of the tail-like pattern is needed in the future.

Preoperative Ultrasonographic Evaluation for Malignancy of Soft-Tissue Sarcoma: A Retrospective Study.

BACKGROUND: Ultrasonography is useful for distinguishing between benign and malignant soft-tissue tumors. However, no study has focused on its usefulness in the differential diagnosis between low-grade and high-grade soft-tissue sarcomas. We conducted a retrospective study to determine the usefulness of the parameters of ultrasonograph and to develop a practical scoring system for distinguishing between high-grade and low-grade sarcomas. METHODS: Twenty-two cases of low-grade and 43 cases of high-grade malignant soft-tissue sarcoma were enrolled. Ultrasonography parameters including the longest diameter, depth of the tumor, echogenicity, tumor margin, and vascularity defined according to Giovagnorio's criteria were analyzed as factors to distinguish between the two types of sarcoma. Significant factors were entered into a multivariate model to define the scores for distinction according to the odds ratio. The usefulness of the score was analyzed via receiver operating characteristic analyses. RESULTS: In univariate analysis, tumor margin, echogenicity, and vascularity were significantly different between low- and high-grade sarcomas. In the multivariate regression model, the odds ratio for high-grade vs. low-grade sarcoma was 8.8 for tumor margin, 69 for echogenicity, and 8.3 for vascularity. Scores for the risk factors were defined as follows: 1, ill-defined margin; 2, hypoechoic echogenicity; and 1, type IV in Giovagnorio's criteria. The sum of each score was confirmed by receiver operating characteristic analysis. The area under the curve was 0.95, with a cut-off score of 3, indicating that the scoring system was useful. CONCLUSION: The ultrasonography parameters of tumor margin, echogenicity, and vascularity are useful for distinguishing between low- and high-grade sarcomas.

Preoperative evaluation of intraoperative blood loss during malignant soft tissue tumor resection by ultrasonography.

BACKGROUND: Preoperative evaluation of the risk of surgery-related blood loss in malignant soft tissue tumor resection is difficult because of wide variations in histological subtype, malignancy, location, and size. Ultrasonography is useful for the evaluation of blood flow around a soft tissue tumor and has the potential to preoperatively estimate intraoperative blood loss in tumor resection. To date, there has been no report regarding blood loss evaluation using ultrasonography in this field. PATIENTS AND METHODS: The usefulness of information obtained by ultrasonography, including tumor size, vessel density in the tumor, and blood flow volume in the vessels, was analyzed for the prediction of intraoperative blood loss in malignant soft tissue tumor resection. RESULTS: Vessel density in the tumor and blood flow in the vessels were identified as independent risk factors for blood loss. Using these factors, a new index for the prediction of blood loss was established. Receiver operating characteristic analyses revealed a high area under the curve value (0.80), confirming the accuracy of the index for the prediction of blood loss. CONCLUSION: Ultrasonography is a useful modality for predicting intraoperative blood loss in malignant soft tissue tumor surgery.

Differential diagnosis between benign and malignant soft tissue tumors utilizing ultrasound parameters.

PURPOSE: Preoperative discrimination between benign and malignant soft tissue tumors is critical for the prevention of excess application of magnetic resonance imaging and biopsy as well as unplanned resection. Although ultrasound, including power Doppler imaging, is an easy, noninvasive, and cost-effective modality for screening soft tissue tumors, few studies have investigated reliable discrimination between benign and malignant soft tissue tumors. METHODS: To establish a modality for discrimination between benign and malignant soft tissue tumors using ultrasound, we extracted the significant risk factors for malignancy based on ultrasound information from 40 malignant and 56 benign pathologically diagnosed soft tissue tumors and established a scoring system based on these risk factors. RESULTS: The maximum size, tumor margin, and vascularity evaluated using ultrasound were extracted as significant risk factors. Using the odds ratio from a multivariate regression model, a scoring system was established. Receiver operating characteristic analyses revealed a high area under the curve value (0.85), confirming the accuracy of the scoring system. CONCLUSION: Ultrasound is a useful modality for establishing the differential diagnosis between benign and malignant soft tissue tumors.

D-dimer levels in the differential diagnosis between lipoma and well-differentiated liposarcoma.

BACKGROUND: Lipoma and well-differentiated liposarcoma (WDLS) are two representative lipogenic soft tissue tumors that have similar clinical, radiological, and pathological characteristics. Accordingly, it is difficult to distinguish these tumors preoperatively. Plasma D-dimer levels are associated with the status of tumor progression, and we hypothesized that D-dimer levels could contribute to differential diagnosis. The D-dimer levels of these two entities have not yet been reported. PATIENTS AND METHODS: We investigated 43 cases of lipoma and 14 cases of WDLS. We evaluated the utility of D-dimer levels and other clinicopathological factors for preoperative differential diagnosis between the two entities. RESULTS: Receiver operating characteristic analysis revealed that the D-dimer level may contribute to differential diagnosis (area under the curve=0.73). Univariate and multivariate models demonstrated that plasma D-dimer levels (p=0.001 (univariate), and p=0.006 (multivariate)) and lower extremity location (p=0.006 (univariate), and p=0.03 (multivariate)) were independent risk factors for WDLS. CONCLUSION: The D-dimer level may be a helpful marker for preoperative differential diagnosis between lipoma and WDLS.

Peristalsis gap sign at cine magnetic resonance imaging for diagnosing strangulated small bowel obstruction: feasibility study.

PURPOSE: The aim of this study was to determine the feasibility of cine magnetic resonance imaging (MRI) for diagnosing strangulated small bowel obstruction (SBO). MATERIALS AND METHODS: This study included 38 patients with clinically confirmed SBO who had undergone cine MRI. Cine MRI scans were evaluated regarding the presence of the "peristalsis gap sign" (referring to an akinetic or severely hypokinetic closed loop), indicating strangulation. Computed tomography (CT) was performed in 34 of 38 patients with (n = 25) or without (n = 9) contrast enhancement. CT images were evaluated using a combination of criteria (presence of hyperattenuation, poor contrast enhancement, mesenteric edema, wall thickening, massive ascites) indicating strangulation. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of cine MRI and CT for the diagnosis of strangulation were calculated and compared using surgical findings and the clinical course as the reference standard. RESULTS: Sensitivity, specificity, PPV, and NPV of cine MRI were 100%, 92.9%, 83.3%, and 100%, respectively; and those of CT (of which 26.5% was performed without contrast enhancement) were 66.7%, 92.0%, 75.0%, and 88.5%, respectively. There was no significant difference in diagnostic accuracy between the two methods (P = 0.375). CONCLUSION: Cine MRI is a feasible and promising technique for diagnosing strangulation.

Malignant pigmented villonodular synovitis in the knee - report of a case with rapid clinical progression.

Malignant pigmented villonodular synovitis (PVNS) (or malignant giant cell tumor of tendon sheath (GCTTS) is an extremely rare condition defined as a malignant lesion occurring with concomitant or previously documented PVNS at the same site. To date, only less than 20 cases have been reported in English literatures. We report a case of malignant PVNS in the knee in a 56-year-old woman with unpredictable rapid progression. This case raised a caution that when atypical components in specimens of recurrent benign PVNS are detected, even if low-grade or tiny, both pathologists and surgeons should consider the risk of malignant PVNS, which could display aggressive clinical progression.

Demonstration of spinal cord and nerve root abnormalities by diffusion neurography.

OBJECTIVE: Diffusion-weighted magnetic resonance imaging postprocessed by maximum-intensity projection reportedly demonstrates the nerve roots. We modified this technique using a fluid-attenuated inversion-recovery-based diffusion-tensor scan using parallel imaging and evaluated its feasibility in demonstrating spinal cord and nerve root abnormalities. METHODS: We applied this technique to 18 patients with miscellaneous pathological conditions that included multiple sclerosis, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), neurofibromatosis (NF), schwannoma, cord injury, and tethered cord. The neurographic images were visually assessed regarding the lesion depiction. RESULTS: In each subject, not only the cord but also the nerve roots were visualized. This technique demonstrated cord plaques of multiple sclerosis (5/6 cases), enlarged nerve roots in CIDP (3/3 cases), multiple neurogenic tumors in NF (3/3 cases), and schwannoma (1/1 case). It better demonstrated nerve root abnormalities of CIDP (3/3 cases) and NF (2/3 cases) than conventional magnetic resonance images. CONCLUSION: This technique can effectively demonstrate most of the cord and nerve root pathology.

Diffusion tensor tractography of the lower spinal cord.

INTRODUCTION: We employed a diffusion-tensor (DT) imaging technique involving a single-shot echo-planar sequence in combination with parallel imaging for tractography of the lower spinal cord and assessed the feasibility of this technique. METHODS: Images were obtained at 1.5 T using a five-channel receiver coil. We used a single-shot echo-planar sequence with parallel imaging to acquire diffusion-weighted (DW) images in the axial plane with phase encoding in the right-left direction. A motion-probing gradient was applied in six directions with a b-value of 1,000 s/mm(2). The scan time was 5 min 15 s. On a reconstructed DW image in the sagittal plane, the spinal cord was included in a single region-of-interest to generate a tractogram of the entire cord in seven volunteers and nine patients with spinal canal stenosis or vertebral metastasis. RESULTS: In each subject, although the conus medullaris and cauda equina were continuously visualized, the cord was demonstrated as a bundle of tracts color-coded in the z-axis. Nerve roots were depicted showing color-coding in the x- and y-axes. In the patient group, displacement of the cord was depicted showing changes in the color of the cord. Displacement of the proximal nerve roots was also depicted in the two patients with vertebral metastasis. CONCLUSION: DT imaging using parallel imaging shows potential as a method for routine tractography of the lower spinal cord.

Comparison of MRI sequences to detect ventriculitis.

OBJECTIVE: The ability of different MRI sequences to depict characteristic findings suggestive of ventriculitis was compared. CONCLUSION: The study comprised 20 brain MRI studies in 13 patients who had a final diagnosis of ventriculitis. Both diffusion-weighted imaging and FLAIR imaging were equally and highly sensitive for detecting intraventricular debris and pus--the most common MRI finding suggestive of ventriculitis. FLAIR imaging was superior to contrast-enhanced T1-weighted imaging for depicting ventricular wall abnormalities--a less common finding that also is suggestive of ventriculitis.

Value of diffusion-weighted MR imaging in acute cervical cord injury as a predictor of outcome.

INTRODUCTION: We analyzed the findings of diffusion-weighted (DW) imaging using the single-shot fast spin-echo sequence in acute cervical cord injury and evaluated the usefulness of this method for predicting the prognosis. METHODS: Our patient group comprised 14 patients examined 2 h to 3 days after injury. First, we visually evaluated the DW imaging findings in all patients. Apparent diffusion coefficient (ADC) maps were also assessed in 13 patients. Second, we assessed follow-up magnetic resonance (MR) examinations obtained in six patients whose DW images showed hyperintensity. Third, we reviewed the functional outcome at discharge. RESULTS: The lesions showed hyperintensity in ten patients, and no abnormal signal was noted in the remaining four patients. The ADC maps showed restricted diffusion in all patients with hyperintensity on DW imaging except in one patient for whom the ADC map was unavailable. Repeated MR examinations obtained in six of the ten patients showed either myelomalacia or exacerbation. Seven of the ten patients (70%) required assistance and the other three were independent. Among the four patients without hyperintensity on DW imaging, three (75%) were independent and only one required assistance. CONCLUSION: DW imaging in acute cervical cord injury often reveals restricted diffusion. This finding may predict an unfavorable functional prognosis.

Postoperative assessment of extracranial-intracranial bypass by time-resolved 3D contrast-enhanced MR angiography using parallel imaging.

PURPOSE: Our goals were to assess image quality of time-resolved contrast-enhanced MR angiography (CE MRA), by using 3D data acquisition along with a parallel imaging technique that can improve temporal resolution and to compare this technique with 3D-time-of-flight (TOF) MRA in the postoperative assessment of extracranial (EC)-intracranial (IC) bypass surgery. METHODS: On a 1.5T imaging system, we performed CE MRA by using a 3D fast field-echo sequence in combination with a parallel imaging technique, to obtain images in the coronal plane centered at the postoperative site. Our patient group comprised 17 patients, including 13 after superficial temporal artery-middle cerebral artery (MCA) anastomosis, 3 after external carotid artery-MCA anastomosis, and one after extracranial vertebral artery-posterior cerebral artery anastomosis. Visualization of the anastomosis and the distal flow on the CE-MRA images was assessed comparatively with that on 3D-TOF MR angiograms obtained at the same time. In 6 patients, we also compared the efficiency of visualization on CE-MRA images with that on conventional angiograms. RESULTS: A temporal resolution of 0.8 s/frame could be achieved with the technique employed. The bypass was better demonstrated postoperatively on CE-MRA images than on 3D-TOF MR angiograms in 13 patients (76%), whereas the 2 methods were equivalent in 4 patients (24%). Good correspondence of results was observed in the 6 patients for whom CE MRA and conventional digital subtraction angiography (DSA) images were compared. CONCLUSION: CE MRA by using the parallel imaging technique can increase image acquisition speed with sufficient image quality. This technique is at least equivalent to 3D-TOF MRA to evaluate the postoperative status of EC-IC bypass.