Detectability of the choroid plexus of the third ventricle with magnetic resonance ventriculography.

PURPOSE: To clarify the detectability of the choroid plexus of the third ventricle (ChPl3V) with magnetic resonance ventriculography (MRVn) employing a steady-state free precession (SSFP) sequence in comparison to surgical endoscopic movies as a golden standard, as we encountered some clinical cases of total agenesis of corpus callosum (ACC) where we could not recognize the choroid plexus of the third ventricle and found no previous article addressing this problem. MATERIALS AND METHODS: This retrospective study included consecutive patients from 2010 to 2016 for whom endoscopic evaluation of the third ventricle was conducted. The anterior portion of the right and left streaks of ChPl3V was evaluated in 8 patients on 16 sites, while the posterior portion of both streaks of ChPl3V was evaluated in 13 patients on 26 sites. Sensitivity of MRVn to visualize ChPl3V with endoscopic movies as the golden standard was calculated. RESULTS: Sensitivity of MRVn in visualizing the anterior portion of ChPl3V was 0.813, and that for the posterior portion 0.692. The anterior portion of ChPl3V was visualized in all cases where no tumor contacted the foramen of Monro. CONCLUSION: MRVn visualizes the anterior portion of ChPl3V with significant sensitivity and the posterior portion with lower one.

Improved wedge method for the measurement of sub-millimeter slice thicknesses in magnetic resonance imaging.

The standard method for measuring the slice thickness of magnetic resonance images uses the inclined surface of a wedge (wedge method); it is sensitive to small increases in noise because of the differentiation of the edge response function (ERF) required. The purpose of this study was to improve the wedge method by fitting a curve to the ERF. The curve-fit function was obtained by convolving an ideal ERF (a ramp function) with a Gaussian function to represent ERF blurring. Measurements of 5- and 3-mm slice thicknesses were performed on a 3T scanner using the conventional wedge method, the improved wedge method, and another standard method using an inclined slab (slab method). Subsequently, 0.5- and 0.25-mm slice thicknesses from multiple slices acquired using a three-dimensional sequence were measured using the improved wedge method. When measuring 5-mm slices, the differences in measurements obtained using the improved wedge method and the conventional slab and wedge methods were very small: <0.6% of the 5-mm slice thickness. The difference was ≤1.7% for 3-mm slices. For 0.5- and 0.25-mm slices, the mean values obtained using the improved wedge method were 0.543 ± 0.007 mm and 0.247 ± 0.015 mm, with a 1.2 and 5.9% coefficient of variation across slices, respectively. The improved wedge method is valid and potentially applicable to the measurement of sub-millimeter slice thicknesses.

A malignant solitary fibrous tumour arising from the first lumbar vertebra and mimicking an osteosarcoma: a case report.

BACKGROUND: A solitary fibrous tumour (SFT) is an unusual neoplasm typically found in soft tissues. Although SFTs can arise in the bones, they very rarely arise in the vertebral arch. Here, we describe a case of a SFT that arose in the vertebral arch of the first lumbar (L1) spinal vertebrae and mimicked osteosarcoma. CASE PRESENTATION: A 49-year-old woman presented with a 2-month history of lower back pain and a lumbar region mass. Magnetic resonance imaging demonstrated a heterogeneously enhanced mass in the L1 vertebral arch. The patient received neoadjuvant chemotherapy, followed by a surgical procedure comprising an anterior spinal fusion and en bloc resection. Histologically, our initial diagnosis was osteosarcoma. The postoperative course was uneventful, and the patient received adjuvant chemotherapy. However, the tumour metastasised to the lung 5 years after the first surgery, and a second surgery was performed for lung tumour resection. The histology of the metastatic lung tumour appeared similar to that of the malignant SFT, and the specimen from the first surgery was re-examined. Immunohistochemically, the tumour was positive for STAT6. Reverse transcription-polymerase chain reaction revealed a NAB2-STAT6 fusion gene, thus confirming our final diagnosis of malignant SFT. The patient died of disease progression 8 years after the first surgery; however, there was no evidence of local recurrence. CONCLUSIONS: Malignant SFT in the vertebral arch is extremely rare and very difficult to distinguish histologically an osteoid from lace-like collagen. STAT6 immunostaining is useful for distinguishing malignant SFTs from other neoplasms. Although it is difficult to completely resect a SFT arising from the spine, we demonstrated the feasibility of an en bloc resection of spinal tumours arising from posterior elements, without local recurrence.

Disappearance of giant cells and presence of newly formed bone in the pulmonary metastasis of a sacral giant-cell tumor following denosumab treatment: A case report.

A giant-cell tumor of the bone (GCTB) is a benign but locally aggressive bone tumor. Recently, the receptor activator of nuclear factor κB (RANK) ligand inhibitor, denosumab, has demonstrated activity against giant-cell tumors. The current study reports a case of a sacral GCTB with lung metastasis. A 19-year-old male patient presented with right buttock pain and right lower leg pain, and a sacral GCTB was diagnosed based on the histological analysis of a biopsy specimen. The patient was successfully treated with neoadjuvant denosumab therapy, which allowed curettage. In addition, the pulmonary nodule reduced in size following denosumab administration, and surgical resection was performed. Since the operation, the patient has been managed with the continued use of denosumab with no sign of recurrence. Microscopic findings from the surgical specimen following denosumab treatment revealed that the giant cells had disappeared and woven bone had formed. The specimen from the pulmonary nodule exhibited similar findings to the surgical specimen. It was reported that denosumab treatment was able to reduce the number of giant cells and RANK-positive stromal cells, and cause the formation of new bone in the primary lesion. The present study reports the first case to demonstrate the efficiency of denosumab in treating pulmonary metastasis of GCTB.

Extraskeletal myxoid chondrosarcoma arising in the femoral vein: a case report.

Soft tissue tumors arising in deep veins of the extremities are uncommon, although a few cases of synovial sarcoma or leiomyosarcoma arising in the femoral vein have been documented. However, to the best of our knowledge, an extraskeletal myxoid chondrosarcoma (EMC) arising in the femoral vein has not been reported in the English literature. We report a case of EMC arising in the femoral vein of a 70-year-old man who presented with right leg edema and was diagnosed with a deep venous thrombosis (DVT) by computed tomography (CT). Magnetic resonance imaging (MRI) revealed a mass in the right proximal thigh that was diagnosed as myxomatous sarcoma by aspiration cytology, and anticoagulant therapy was initiated. The mass was surgically resected en bloc, including the femoral vein and surrounding soft tissue, and the femoral artery was preserved. The femoral vein was not reconstructed. The histologic diagnosis was an extraskeletal myxoid chondrosarcoma. The patient received postoperative local radiation treatment, with a total dose of 60 Gy, and is currently doing well with no evidence of local recurrence or metastasis at 8 months after surgery. In summary, this case report shows that EMC can arise in the femoral vein, and that reconstruction of the femoral vein is not always necessary during surgery for soft tissue tumors.

Clinical results after the multidisciplinary treatment of spinal arteriovenous fistulas.

PURPOSE: We retrospectively evaluated the clinical outcome after multidisciplinary treatment of spinal arteriovenous fistulas (AVFs) in terms of the Aminoff-Logue grading scale (ALS) to depict the outcome in a perspective pertinent to the quality of everyday living. MATERIALS AND METHODS: Twenty-six spinal AVFs in 25 patients were angiographically diagnosed from April 1998 through April 2012 and treated by endovascular embolization or surgery. When both treatment procedures seemed feasible, embolization was undertaken as the initial treatment. Motor and gait disturbance at follow-up was retrospectively graded according to ALS. RESULTS: All lesions were localized at the thoracolumbar or sacral levels and include six epidural AVFs with intradural venous reflux, 14 dural AVFs, and six perimedullary AVFs. Embolization was performed as the initial treatment for 17 lesions, while open surgery was performed for the others as well as for residual or recurrent lesions after embolization. All lesions were completely occluded except three perimedullary AVFs. At clinical follow-up of 1-153 months (mean 53.3), amelioration of gait disturbance with reduction of ALS scores was noted for 13 lesions and amelioration of micturition for 13 lesions as well. CONCLUSION: Clinical functional status was improved for half of the lesions after the multidisciplinary treatment.

Preoperative evaluation of the vertebral arteries and posterior portion of the circle of Willis for cervical spine surgery using 3-dimensional computed tomography angiography.

STUDY DESIGN: A retrospective analysis using prospectively collected data from 3-dimensional computed tomography angiography (3D-CTA). OBJECTIVE: To investigate the frequency of anomalous vertebral arteries (VA) and variations of the posterior portion of the circle of Willis (PPCW) using 3D-CTA for preventing perioperative iatrogenic vascular complications. SUMMARY OF BACKGROUND DATA: Some studies have reported that preoperative 3D-CTA is useful for determining the VA blood flow in the cervical spine. However, preoperative 3D-CTA has not been used for evaluating PPCW, which functions as vessels collateral to the basilar artery in the case of iatrogenic VA injury. METHODS: The study included 100 consecutive patients (61 males and 39 females; mean age, 60.4 ± 15.4 yr; range, 11-86 yr) who underwent cervical decompression and/or instrumentation between April 2008 and May 2012. We measured the diameters of the VA (VAD), posterior communicating artery (PCOMD), first segment of the posterior cerebral artery (P1D), and basilar artery (BAD) twice and determined the frequency of anomalous VA and PPCW variations. RESULTS: Hypoplastic VA, hypoplastic PCOM, and hypoplastic P1 were detected in 11 (11.0%), 81 (81.0%), and 13 patients (13.0%), respectively. Hypoplastic PCOM-P1 and hypoplastic basilar artery were observed in 87 (87.0%) and 3 patients (3.0%), respectively. Overall, 47 patients (47.0%) possessed some degree of abnormal VA blood flow.There were 7 patients (7.0%) with both unilaterally hypoplastic VA and bilaterally hypoplastic PCOM-P1s, in whom iatrogenic VA injury on the dominant side could have caused lethal vascular complications. We termed the hypoplastic VA of the contralateral side without collateral vessels as "critical VA." CONCLUSION: The VAs and PPCW vary considerably. Preoperative 3D-CTA provides important information for preventing tragic vascular complications caused by iatrogenic VA injury. Taking the risk of radiation into consideration, we recommend this method for patients at the highest risk for iatrogenic VA injury.

Correlation between the site of pulmonary embolism and the extent of deep vein thrombosis: evaluation by computed tomography pulmonary angiography and computed tomography venography.

PURPOSE: The aim of this study was to evaluate the relation between the sites of pulmonary embolism (PE) and deep vein thrombosis (DVT) by computed tomography pulmonary angiography (CTPA) and CT venography (CTV) of the pelvis and lower extremities. MATERIALS AND METHODS: We retrospectively reevaluated CTPA-CTV data sets for 227 consecutive patients suspected of having a PE. The PEs were divided into proximal (located at the lobar artery or proximal to it) and distal groups. DVTs were divided into proximal (located above the knee) and distal groups. Cohen's kappa statistic and chi-squared tests were performed. RESULTS: The incidence of PE was significantly higher in patients with a proximal DVT than with a distal DVT (P < 0.01). In patients with a proximal DVT, the incidence of proximal PE was significantly higher than that of distal PE (P < 0.05). In patients with a proximal DVT, the incidence of PE was significantly higher in patients with a right-side DVT than with a left-side DVT (P < 0.05). CONCLUSION: Proximal PEs were correlated with proximal DVTs. Patients with a proximal DVT tended to have a PE, especially with a right-proximal DVT. Hence, the presence of a right-proximal DVT has the potential for serious complications, and carefully diagnosis is required for PE and DVT.

Relationship between heart rate and optimal reconstruction phase in dual-source CT coronary angiography.

RATIONALE AND OBJECTIVES: To evaluate reconstruction image quality at the systolic and diastolic cardiac phases and determine the optimal phase for reconstruction according to heart rate when using dual-source computed tomography (CT) with 75 ms temporal resolution. MATERIALS AND METHODS: We retrospectively reviewed the CT datasets of 35 patients with regular heartbeats who underwent coronary CT angiography. Images were reconstructed in 2% steps between 32 and 78% of the beat-to-beat interval. Two experienced radiologists determined the reconstruction interval with the fewest motion artifacts and the motion score of each vessel for the systolic and diastolic phases. Subgroup analysis was performed in patients having heart rates of <70, 70-80, and >80 beats per minute (bpm). RESULTS: In the subgroup with heart rates of <70 bpm, the diastolic phase reconstruction image quality was significantly better than for the systolic phase (P < .01). In the 70-80 bpm and >80 bpm subgroups, no significant difference was observed. In the diastolic phase, the image quality of the <70 bpm subgroup was significantly better than for the >80 bpm subgroup (P < .05). In all systolic phase subgroups and other diastolic phase subgroups, no significant difference was observed. CONCLUSIONS: Using a DSCT scanner with 75 ms temporal resolution, reconstruction at the diastolic phases should be used for patients with heart rates <70 bpm. For heart rates >70 bpm, larger studies are necessary to determine whether reconstruction at the systolic, diastolic, or both phases should be used.

Laparotomized direct puncture for embolization of a retroperitoneal arteriovenous fistula.

A 28-year-old woman was referred to our institution with hope for another child after having an abortion several months previously to avoid a potential risk of catastrophic hemorrhage from a retroperitoneal arteriovenous fistula (AVF) with enlarged and twisted draining veins in the pelvis. Multiple branches coming from the right lumbar arteries and the right iliac arteries fed fistulae converging on an enlarged venous pouch anterior to the psoas major muscle in the right retroperitoneal space. It seemed impossible to achieve complete occlusion of the lesion in a single session by either transarterial or transvenous approach. A laparotomy and direct puncture of the enlarged draining vein immediately downstream of the venous pouch was performed and embolization was done with n-butyl cyanoacrylate and the aid of coils. Complete occlusion of the retroperitoneal AVF was achieved and confirmed in control angiography 5 months later.

Visualization of hemodynamics in intracranial arteries using time-resolved three-dimensional phase-contrast MRI.

PURPOSE: To visualize the hemodynamics of the intracranial arteries using time-resolved three-dimensional phase-contrast (PC)-MRI (4D-Flow). MATERIALS AND METHODS: MR examinations were performed with a 1.5T MR unit on six healthy volunteers (22-50 years old, average = 30 years). 4D-Flow was based on a radiofrequency (RF)-spoiled gradient-echo sequence, and velocity encoding (VENC) was performed along all three spatial directions. Measurements were retrospectively gated to the electrocardiogram (ECG), and cine series of three-dimensional (3D) data sets were generated. The voxel size was 1 x 1 x 1 mm, and acquisition time was 30-40 minutes. 4D data sets were calculated into time-resolved images of 3D streamlines, 3D particle traces, and 2D velocity vector fields by means of flow visualization software. RESULTS: We were able to see the 3D streamlines from the circle of Willis to the bilateral M2 segment of the middle cerebral arteries (MCAs). Time-resolved images of 3D particle traces also clearly demonstrated intracranial arterial flow dynamics. 2D velocity vector fields on the planes traversing the carotid siphon or the basilar tip were clearly visualized. These results were obtained in all six volunteers. CONCLUSION: 4D-Flow helped to elucidate the in vivo 3D hemodynamics of human intracranial arteries. This method may be a useful noninvasive means of analyzing the hemodynamics of intracranial arteries in vivo.

Contrast-enhanced three-dimensional MR angiography with an elliptical centric view for the evaluation of intracranial aneurysms.

The purpose of this study was to assess the feasibility of high spatial resolution, selective arterial phase, 3D contrast-enhanced (CE) MR angiography with first pass bolus, software-trigger, elliptical centric view ordering in the detection of intracranial aneurysms. Our study included nine consecutive patients with ten intracranial aneurysms. 3D TOF MR angiography and 3D CE MR angiography were carried out with a 1.5-T MR scanner. 3D CE MR angiography was performed with an automated bolus detection algorithm and elliptical centric view order using ultrafast SPGR with a spatial resolution of 0.63x0.83x0.5 mm and imaging time of 55 s. Observers detected seven of ten aneurysms on 3D TOF MR angiograms and nine of ten aneurysms on 3D CE MR angiograms. 3D CE MR angiography clearly revealed an IC-PC aneurysm with a relatively smaller neck, a broad-based small aneurysm originating from tortuous and dilated MCA bifurcation, and a residual aneurysm and parent vessels adjacent to metallic aneurysmal clips, which had relatively low signal intensities on 3D TOF MR angiograms. 3D CE MR angiography was found to be a good and promising technique for detecting intracranial aneurysms with small necks and slow flow, vasculature with aneurysmal clips and tortuous vasculature with disturbed flow.

Visualization of spinal cord motion associated with the cardiac pulse by tagged magnetic resonance imaging with particle image velocimetry software.

OBJECTIVE: The purpose of this study was to evaluate whether or not tagged magnetic resonance (MR) imaging with particle image velocimetry (PIV) software could reveal spinal cord motion clearly. METHODS: Six volunteers were enrolled in this study. Tagged MR imaging using fast spoiled gradient-recalled acquisition in the steady state with spatial modulation of the magnetization technique was performed using a 1.5-T MR system. RESULTS: Sagittal vector maps analyzed by PIV software revealed entire spinal cord motion sequentially during the cardiac cycle. The cervical spinal cord initially moved in a caudal direction and then continually oscillated from a cephalic-to-caudal direction. Each volunteer had a different cycle. In the thoracic spinal area, similar findings were observed, although they were slightly less clear than in the cervical area. CONCLUSION: Tagged MR imaging combined with PIV software, referred to as tagged MR image velocimetry, revealed spinal cord motion associated with the cardiac pulse, especially in the cervical spine.

Magnetic resonance imaging findings of angiosarcoma of the scalp.

OBJECTIVE: The purpose of this study was to investigate the magnetic resonance (MR) imaging findings of angiosarcoma of the scalp retrospectively. METHODS: Eight patients with angiosarcoma of the scalp were included in this study. All patients were examined with 1.5-T MR imaging units and commercially available head coils. RESULTS: In all 8 patients, MR images revealed thickened scalp or tumors with prolonged T1 and T2 relaxation times. They were well enhanced. T2-weighted MR imaging with fat saturation and contrast-enhanced T1-weighted MR imaging with fat saturation clearly showed tumors invading the subcutaneous fat tissue and muscles. In 4 patients, the tumors were larger on MR images than on inspection. CONCLUSIONS: Magnetic resonance imaging was useful in determining the extent of angiosarcoma of the scalp because it visualized the tumor invasion into surrounding structures that could not be seen on physical inspection.

Effect of a portal venous stent for gastrointestinal hemorrhage from jejunal varices caused by portal hypertension after pancreatoduodenectomy.

We report herein the case of a 64-year-old man successfully treated by portal venous stent placement for repeated gastrointestinal bleeding associated with jejunal varices. He was admitted to our hospital with melena 8 years after having a pancreatoduodenectomy for carcinoma of the papilla of Vater. From portogram findings showing severe portal vein (PV) stenosis and dilated collaterals through the jejunal vein of the Roux-en-Y loop, jejunal varices resulting from PV stenosis were suspected as the cause of the melena. A metallic stent was placed in the PV following percutaneous transhepatic PV angioplasty. Although the cure of hemorrhagic jejunal varices caused by PV stenosis is difficult in patients who have undergone major abdominal surgery, patency of the stent in this patient has been maintained for 32 months without gastrointestinal hemorrhage. Metallic stent placement is recommended as a useful treatment for PV stenosis that is less invasive than open surgery.

[Interventonal radiology in the splanchnic arteries].

We present a review of interventional radiology in the splanchnic arteries, focusing on what has been achieved and the remaining challenges. Embolization is currently the treatment of choice for hemorrhagic events due to anastomotic leakage after intestinal anastomosis, although occasional association with liver necrosis poses a hazardous problem yet to be overcome. For splanchnic artery aneurysms, we should recognize that we are not, in reality, well informed about their natural history. The indications for the embolization of aneurysms is limited depending on the morphology of the aneurysm and surrounding vessels. Rotational angiography and other recently developed imaging techniques can help analyze the vascular anatomy of every lesion in decision making on the appropriate treatment for each patient when choosing between embolization and surgical obliteration. Partial splenic artery embolization for hypersplenism has been highly evaluated since the 1980s, although treatment indication should be carefully studied for patients with severe liver dysfunction. For acute mesenteric artery occlusion, local fibrinolysis should always be backed up by or combined with surgical treatment, and the treatment outcome is still sometimes dismal, suggesting one of the boundaries of modern medicine.

Preliminary study of tagged MR image velocimetry in a replica of an intracranial aneurysm.

Flow dynamics in intracranial aneurysms and their adjacent parent vessels play important roles in the development and rupture of intracranial aneurysms. Combined with tagged MR imaging and the use of particle image velocimetry software, tagged MR image velocimetry reveals flow vectors, vorticity, and shear strains at each location in the aneurysm replica every 9 milliseconds. This technique is a promising and noninvasive technique for assessing hemodynamics in intracranial aneurysms.