The choice of region of interest after spinal procedures alters bone mineral density measurements.

PURPOSE: Vertebrae affected by artifacts, such as metallic implants or bone cement, should be excluded when measuring the spine bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Exclusion may be performed using two methods: first, the affected vertebrae are included in the region of interest (ROI) and subsequently excluded from the analysis; second, the affected vertebrae are completely excluded from the ROI. This study aimed to investigate the influence of metallic implants and bone cement on BMD with and without the inclusion of artifact-affected vertebrae in the ROI. METHODS: DXA images of 285 patients, including 144 with spinal metallic implants and 141 who had undergone spinal vertebroplasty from 2018 to 2021, were retrospectively reviewed. Spine BMD measurements were performed when the images were evaluated using two different ROIs for each patient during the same examination. In the first measurement, the affected vertebrae were included in the ROI; however, the affected vertebrae were excluded from the BMD analysis. In the second measurement, the affected vertebrae were excluded from the ROI. Differences between the two measurements were evaluated using a paired t-test. RESULTS: Among 285 patients (average age, 73 years; 218 women), spinal metallic implants led to an overestimation of bone mass in 40 of 144 patients, whereas bone cement resulted in an underestimation of bone mass in 30 of 141 patients when the first measurement was compared with the second measurement. The opposite effect occurred in 5 and 7 patients, respectively. Differences in results between the inclusion and exclusion of the affected vertebrae in the ROI were statistically significant (p<0.001). Spinal implants or cemented vertebrae included in the ROI might significantly alter BMD measurements. Additionally, different materials were associated with varying modifications in BMD. CONCLUSION: The inclusion of affected vertebrae in the ROI may notably alter BMD measurements, even when they are excluded from the analysis. This study suggests that the vertebrae affected by spinal metallic implants or bone cement should be excluded from the ROI.

Association of possible sarcopenic obesity with osteoporosis and fragility fractures in postmenopausal women.

Possible sarcopenic obese women had a decreased likelihood of osteoporosis but an increased likelihood of fragility fractures compared with non-sarcopenic non-obese and sarcopenia-only women. Furthermore, possible sarcopenic obese women had lower values of trabecular bone score than non-sarcopenic non-obese and sarcopenia-only women. PURPOSE: The coexistence of possible sarcopenia and obesity may have opposing effects on osteoporosis. This study aimed to investigate whether possible sarcopenic obesity is associated with osteoporosis or fragility fracture. METHODS: In this cross-sectional study of 1007 postmenopausal women from Taiwan, bone mineral density of the spine and hips was evaluated using dual-energy X-ray absorptiometry (DXA), and bone microarchitecture was evaluated using the trabecular bone score (TBS) derived from a lumbar spine image acquired by DXA. According to the definition of sarcopenia by the 2019 Asian Working Group for Sarcopenia, possible sarcopenia was defined by either low muscle strength or reduced physical performance. Obesity was defined as a body mass index of ≥ 27 kg/m2. Based on the presence of possible sarcopenia and obesity, study participants were classified as follows: control (non-sarcopenic non-obese), sarcopenic (non-obese), obese (non-sarcopenic), and sarcopenic obese. Prevalent fragility fractures were determined by retrospectively reviewing medical records. RESULTS: In this study, 10.1% of participants were classified as sarcopenic obese, 9.1% as obese, 35.2% as sarcopenic, and 45.6% as control. Relative to the control group, the sarcopenic obese group (OR, 0.28; 95% CI 0.18, 0.46) and obese group (OR, 0.38; 95% CI 0.23, 0.61) had a decreased likelihood of osteoporosis. However, the sarcopenic obese group (OR, 2.29; 95% CI 1.31, 4.00) and obese group (OR, 1.94; 95% CI 1.04, 3.62) had an increased likelihood of fragility fractures than with the control group. In addition, the sarcopenic obese group had a higher likelihood of fragility fractures than the sarcopenic group. Possible sarcopenic obese women also had significantly lower TBS values than those in the control and sarcopenic groups. CONCLUSIONS: Possible sarcopenic obese women had a lower likelihood of osteoporosis but a higher likelihood of fragility fractures than non-sarcopenic non-obese and sarcopenia-only women. Furthermore, possible sarcopenic obese individuals had lower values of TBS than non-sarcopenic non-obese and sarcopenia-only women.

The Impact of the "Osteo" Component of Osteosarcopenia on Fragility Fractures in Post-Menopausal Women.

Osteosarcopenia, the coexistence of bone and muscle loss, is common in older adults, but its definition lacks international consensus. This cross-sectional study (n = 1199 post-menopausal women) aimed to determine the association between osteosarcopenia and fragility fractures and to investigate the impact of the definition of the "osteo" component. Bone mineral density and bone microarchitecture were measured by dual-energy X-ray absorptiometry and the trabecular bone score (TBS), respectively. The "osteo" component of osteosarcopenia was classified as osteoporosis (T-score ≤ -2.5 SD), osteopenia/osteoporosis (T-score < -1 SD), and high-fracture-risk osteopenia (-2.5 SD < T-score < -1 SD)/osteoporosis (T-score ≤ -2.5 SD). The Fracture Risk Assessment Tool was used to identify high-fracture-risk osteopenia. Altogether, 30.3%, 32.2%, 14.4%, and 23.1% of participants had osteosarcopenia, osteoporosis alone, sarcopenia alone, and neither condition, respectively. The odds ratios between osteosarcopenia and fragility fractures were 3.70 (95% CI: 1.94-7.04) for osteosarcopenia, 2.48 (95% CI: 1.30-4.71) for osteoporosis alone, and 1.87 (95% CI: 0.84-4.14) for sarcopenia alone. Women with osteosarcopenia also had lower TBS, indicating worse bone microarchitecture. In conclusion, women with osteosarcopenia were more likely to have previously sustained a fracture compared to those without osteosarcopenia, with sarcopenia alone, and with osteoporosis alone. The relationship between osteosarcopenia and fracture risk may be best identified when considering high-fracture-risk osteopenia and osteoporosis.

Hand grip strength in predicting the risk of osteoporosis in Asian adults.

INTRODUCTION: There is a need for a cost-effective method to identify individuals with a high risk of osteoporosis. This study aimed to investigate the suitability of hand grip strength in predicting the risk of osteoporosis in Asian adults. MATERIALS AND METHODS: In this cross-sectional, hospital-based study of 1007 participants, the bone mineral density of the spine and hips was evaluated using dual-energy X-ray absorptiometry according to the 2019 International Society for Clinical Densitometry official positions. Bone microarchitecture was evaluated using the trabecular bone score, and hand grip strength was measured in the dominant hand using a hand digital dynamometer. RESULTS: Hand grip strength was significantly related to bone density and bone microarchitecture. Moreover, hand grip strength was a significant predictor of osteoporosis in both women and men. For osteoporosis prediction in women, a threshold of 21.9 kg of hand grip strength had a sensitivity of 59%, specificity of 59%, and area under the curve (AUC) of 0.61. In men, a threshold of 28.7 kg had a sensitivity of 66%, specificity of 78%, and AUC of 0.75. The optimal cutoff strengths for osteoporosis depended on age and sex. CONCLUSION: The measurement of hand grip strength is a simple, cost-effective and an easy assessment method for identifying individuals at a high risk of osteoporosis. The cutoff strength for evaluating osteoporosis in adults is age and sex specific.

Comparing self-assessment, functional, and anthropometric techniques in predicting osteoporosis.

The osteoporosis self-assessment tool was more accurate than hand grip strength, gait speed, and calf circumference in predicting osteoporosis in women. Hand grip strength was more accurate than the osteoporosis self-assessment tool, gait speed, and calf circumference in predicting osteoporosis in men. PURPOSE: The osteoporosis self-assessment tool, functional assessment, and anthropometric measurement are different techniques to identify those at risk of osteoporosis. This study aimed to compare the performance of these techniques in predicting osteoporosis. METHODS: In this cross-sectional, hospital-based study including 1109 participants, the bone mineral density of the spine and hips was evaluated using the dual-energy X-ray absorptiometry. The Osteoporosis Self-Assessment Tool was used as a simple clinical risk assessment tool to screen for osteoporosis. Gait speed and hand grip strength were used as functional assessments to predict osteoporosis. Calf circumference was used as an anthropometric measurement to predict osteoporosis risk. RESULTS: In women, the Osteoporosis Self-Assessment Tool was better than hand grip strength, gait speed, and calf circumference in predicting osteoporosis. In contrast, in men, hand grip strength was better than the Osteoporosis Self-Assessment Tool, gait speed, and calf circumference. CONCLUSION: The application of simple, cost-effective techniques for the identification of osteoporosis risk will be beneficial for both screening and patient care when dual-energy X-ray absorptiometry is not available. We suggest that the Osteoporosis Self-Assessment Tool can be used to identify the risk of osteoporosis in women and hand grip strength measurement can be used for men.

Aggressive cavernous sinus dural arteriovenous fistula: Angioarchitecture analysis and embolization by various approaches.

BACKGROUND: Most cavernous sinus dural arteriovenous fistulas (CSDAVFs) present with benign neuro-ophthalmic symptoms. CSDAVFs manifesting with aggressive neurologic symptoms are rare. The purpose of this study was to analyze the different angioarchitectures of aggressive CSDAVFs and to report our experiences of embolization. METHODS: Over the past 10 years, a total of 118 CSDAVFs were managed by embolization. From the databases containing such patient information, nine patients (7.6%) were found to have aggressive CSDAVFs presenting with neurologic deficits. There were seven women and two men, ranging in age from 51 years to 78 years (mean, 66 years). We retrospectively analyzed the angioarchitectures of aggressive CSDAVFs, further reviewing patient and angiographic as well clinical outcomes after embolization. RESULTS: The cause of clinically aggressive CSDAVFs was insufficient fistula drainage because of occlusion (n = 6) or stenosis (n = 1) of the inferior petrous sinus (IPS) or compartment of IPS-cavernous sinus (n = 2) with fistula flow reflux to the veins of brainstem (n = 7) leading to brainstem ischemia, while two fistula flow reflux to the cortical vein leading to cerebral infarction. Transvenous embolization via IPS to fistula was achieved in one case; six patients underwent transorbital access, while transarterial embolization was performed in two cases. Total fistula occlusion was achieved in eight CSDAVFs. All patients had total (n = 7) or partial (n = 2) resolution of their symptoms gradually within 6 months. One patient undergoing transarterial embolization had limb weakness because of inadvertent pial artery occlusion. Their overall mean clinical follow-up period was 17 months. CONCLUSION: Aggressive CSDAVFs are associated with occlusion/stenosis of the IPS or compartment of IPS-cavernous sinus with leptomeningeal reflux. In this limited case series, aggressive CSDAVFs most presented with brainstem ischemia, followed by nonhemorrhagic/hemorrhagic stroke in the cerebrum. Embolization through various access routes is a feasible method to manage these aggressive CSDAVFs, with an acceptable level of periprocedural risks.

Transvenous embolization of cavernous sinus dural arteriovenous fistula via angiographic occlusive inferior petrous sinus.

BACKGROUND: Trans-inferior petrous sinus (IPS) coil embolization is an efficient and safe method to manage cavernous sinus dural arteriovenous fistulas (CSDAVFs). However, some CSDAVFs may be associated with angiographic occlusive IPS making access difficult. The purpose of this study was to report our experience of transvenous embolization of the CSDAVF via angiographic occlusive IPS. METHODS: We reviewed the cases of 20 patients who underwent transvenous embolization via angiographic occlusive IPS over a 6 year period. The study consisted of seven men and 13 women, ranging from 46 years to 78 years of age (mean, 60 years). We retrospectively analyzed the angioarchitecture of the CSDAVFs, the procedural time and the angiographic as well as the clinical outcomes after embolization. RESULTS: True occlusive IPS was found in 13 of the patients, while patent IPS with compartment of the IPS-CS was demonstrated in the remaining seven patients. The microcatheter was successfully navigated to the fistula site of the CS in 16 patients (80%), while such navigation failed in four patients following numerous attempts. The mean procedural times for truly occlusive IPS and for compartment of the IPS-CS were 111 minutes and 129 minutes, respectively. No recurrent fistula was observed on follow-up neuroimages. Three patients had transient third or sixth cranial nerve palsy, and one patient had perforation of the IPS leading to temporary headache. The mean clinical follow-up period was 18 months. CONCLUSION: Angiographic occlusive IPS of CSDAVF may be related to true occlusion of IPS or patent IPS with compartment of the IPS-CS. There is no statistically significant difference in procedural times for these two different fistula anatomies. Transvenous embolization via angiographic occlusive IPS is a safe and effective method to manage CSDAVFs.

Anatomic Variation of Facial Vein in Carotid-Cavernous Fistula and Trans-Facial Vein Embolization.

OBJECTIVE: Trans-facial vein (FV) embolization via the internal jugular vein is an alternative approach to embolization of carotid cavernous fistulas (CCFs). The purpose of this study is to report the anatomic variation of FVs and our experience of trans-FV embolization of CCFs. METHODS: Over 6 years, 26 patients (12 men and 14 women; age range 27-72 years old) with CCFs underwent trans-FV embolization because of anterior drainage of fistulas. We retrospectively analyzed angioarchitecture of the CCFs focusing on the anatomic variations of FVs and angiographic and clinical outcomes after embolization. RESULTS: FVs drained to the internal jugular vein in 10 (38%) cases; FVs unexpectedly emptied into the external jugular vein in 16 (62%) cases. All FVs entered into the internal jugular vein at the level of the hyoid bone. In cases with fistulas to the FV and EJV, the termination of FVs was variable including superior (n = 5), inferior (n = 1), or at the level of the hyoid bone (n = 10). Successful microcatheterization via different insertions of FVs to jugular veins was achieved in all cases. One patient had a small residual fistula, and 2 patients had fistula recurrence. Temporary impairment of cranial nerve III or VI occurred in 4 patients. The mean clinical follow-up time was 18 months. CONCLUSIONS: Trans-FV embolization is an effective and safe method to manage CCFs with anterior drainage. However, anatomic variations of the FV exist, and a careful work-up of fistula venous drainage before trans-FV embolization is essential to reduce erroneous attempts, procedure time, and periprocedural risk.

Update of embolization of intracranial dural arteriovenous fistula.

Intracranial dural arteriovenous fistulas (DAVFs) are abnormal arteriovenous communications within the dura locating near a major venous sinus and are supplied by pachymeningeal arteries. DAVFs represent 10-15% of all intracranial arteriovenous malformations. The natural history and clinical manifestations are determined by location of the DAVFs and their angioarchitecture. Aggressive DAVF is usually associated with leptomeningeal venous drains or reflux. It may present with hemorrhagic or nonhemorrhagic stroke. The goal of embolization of DAVFs is total fistula occlusion without interfering with the normal dura-venous drains. Embolization can be performed by transarterial and/or transvenous routes or direct puncture of affected dural sinus. Selection of embolic materials depends on access route and angioarchitecture of the fistula. With the involution of endovascular devices, embolic materials, and high-quality angiography, endovascular embolization of DAVFs has been proved a safe and effective method of treating these complex cerebrovascular lesions.

Impact of carotid stenting in dizzy patients with carotid stenosis.

BACKGROUND: Little is known about the impact of severe carotid stenosis on health-related quality of life (HRQoL). The aim of this study was to assess the effects of carotid stenting (CAS) on HRQoL in dizzy patients with carotid stenosis. METHODS: Patients with symptomatic (≥60%) or asymptomatic (≥80%) severe carotid stenosis and who complained of dizziness and received CAS were recruited. Two HRQoL questionnaires-a generic survey, the 36-item Short-Form Health Survey and a disease-specific instrument, the Dizziness Handicap Inventory-served as outcome measures. Patients were followed 1 week prior to CAS and 6 months postprocedurally. RESULTS: CAS was performed in 178 consecutive patients, 61 of whom complained of dizziness. Forty-one patients (67.2%, 34 male; mean age, 73.3 ± 10.5 years; range, 47-87 years) completed the study. Twenty asymptomatic volunteers (17 male; mean age, 70.3 ± 9.3 years; range, 54-84 years) served as normal controls. Compared to controls, patients tallied lower scores in the overall total and three subscales (physical, functional, and emotional) of the Dizziness Handicap Inventory (p < 0.01). Similar findings were noted in seven out of eight domains of the 36-item Short-Form Health Survey score. After 6 months, CAS resulted in significantly improved HRQoL (role physical, bodily pain, general health, social function, and role emotional) in these patients. CONCLUSION: CAS resulted in improved HRQoL in patients with severe carotid stenosis who experienced dizziness.

CT of globe rupture: analysis and frequency of findings.

OBJECTIVE: The objective of our study was to evaluate the CT characteristics of globe rupture. MATERIALS AND METHODS: The medical records of patients seen in the emergency department with blunt, penetrating, or explosive orbit injury were retrospectively reviewed. A total of 75 patients (76 injured globes) were included (56 males and 19 females; average age, 45.1 years; age range, 5-95 years). CT examinations were reviewed by two experienced radiologists without knowledge of ophthalmologic findings, original orbital CT images, or surgical outcomes. RESULTS: Of the 76 globe injuries, 33 (43%) were ruptured and 43 (57%) were nonruptured. There were significant differences between the ruptured and nonruptured globes with respect to intraocular hemorrhage, lens dislocation and destruction, an intraocular foreign body, intraocular gas, anterior chamber depth (ACD), and globe deformity and wall irregularity (p < 0.05). There was good interrater agreement between the two radiologists (kappa value range, 0.63-0.96). The average sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT for the detection of globe rupture based on readings by two radiologists were 76%, 85%, 80%, 82%, and 81%, respectively. CONCLUSION: Although CT is extremely useful in the evaluation of ocular trauma, it should not be solely relied on for the diagnosis of globe rupture because of the potentially catastrophic consequences of an undiagnosed injury. A difference in ACD can be diagnostic of globe rupture.

Reverse waffle cone technique in management of stent dislodgement into intracranial aneurysms.

Stent-assisted coil embolization (SACE) is a common method to manage intracranial wide-neck aneurysm. Using this technique, a stent must be successfully deployed into the parent artery to cross the aneurysm neck. We describe the reverse waffle cone technique in management of intra-procedural stent dislodgement during SACE of internal carotid artery (ICA) wide-neck aneurysms. Two patients with unruptured wide-neck ICA aneurysms underwent SACE. Intra-procedural forward stent migration occurred during catheterization with proximal stent dislodgement and migration into the aneurysm sac. Navigation of a second stent to bridge the aneurysm neck failed in one patient because the second stent was impeded by the dislodged stent. Using the reverse waffle cone technique, a microcatheter was navigated into the aneurysm sacs. Coils were safely detached into each aneurysm sac without any device assistance. The two wide-neck aneurysms were successfully treated with preservation of flow to the internal carotid arteries. The complication of intra-procedural distal stent migration and dislodgement, with proximal stent prolapse into an aneurysm sac, may not result in a failure to coil the aneurysm. The reverse waffle cone technique provides an effective treatment in the management of this complication.

Toward the era of a one-stop imaging service using an angiography suite for neurovascular disorders.

Transportation of patients requiring multiple diagnostic and imaging-guided therapeutic modalities is unavoidable in current radiological practice. This clinical scenario causes time delays and increased risk in the management of stroke and other neurovascular emergencies. Since the emergence of flat-detector technology in imaging practice in recent decades, studies have proven that flat-detector X-ray angiography in conjunction with contrast medium injection and specialized reconstruction algorithms can provide not only high-quality and high-resolution CT-like images but also functional information. This improvement in imaging technology allows quantitative assessment of intracranial hemodynamics and, subsequently in the same imaging session, provides treatment guidance for patients with neurovascular disorders by using only a flat-detector angiographic suite-a so-called one-stop quantitative imaging service (OSIS). In this paper, we review the recent developments in the field of flat-detector imaging and share our experience of applying this technology in neurovascular disorders such as acute ischemic stroke, cerebral aneurysm, and stenoocclusive carotid diseases.

How far can the radiation dose be lowered in head CT with iterative reconstruction? Analysis of imaging quality and diagnostic accuracy.

OBJECTIVE: To evaluate the imaging quality of head CT at lowered radiation dose by combining filtered back projection (FBP) and iterative reconstruction (IR) algorithms. METHODS: Experimental group A (n = 66) underwent CT with 43 % tube current reduction, and group B (n = 58) received an equivalent reduced dose by lowering the tube voltage. An age- and sex-matched control group (n = 72) receiving the conventional radiation dose was retrospectively collected. Imaging for the control group was reconstructed by FBP only, while images for groups A and B were reconstructed by FBP and IR. The signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), sharpness, number of infarcts and severity of subcortical arteriosclerotic encephalopathy (SAE) were compared to assess imaging quality and diagnostic accuracy. RESULTS: There were no significant differences in SNRs and CNRs between group A and the control group. There were significantly decreased SNRs and increased CNRs in group B. Image sharpness decreased in both groups. Correlations between detected infarcts and severity of SAE across FBP and IR were high (r = 0.73-0.93). Head diameter was the only significant factor inversely correlated with infratentorial imaging quality. CONCLUSION: Head CT with 43 % reduced tube current reconstructed by IR provides diagnostic imaging quality for outpatient management. KEY POINTS: • Cranial CT using iterative reconstruction provides diagnostic images with 43 % mAs reduction. • Blurring of infratentorial images becomes evident using low-radiation head CT. • Head diameter was inversely correlated with imaging quality in the infratentorium. • Lowering tube kilovoltage requires a higher radiation dose to maintain image quality.

Fistula components of brain arteriovenous malformations: angioarchitecture analysis and embolization prior to gamma-knife surgery.

BACKGROUND: Gamma-knife surgery (GKS) is ineffective for high-flow arteriovenous fistula (AVF). The purpose of this study was to present the angioarchitecture of the AVF of brain arteriovenous malformation (BAVM) and report our experience of endovascular embolization of AVF component prior to GKS. METHODS: In the past 10 years, a total of 523 BAVMs had been treated primarily by GKS. Among these, 10 patients with AVF components were identified and referred for embolization prior to GKS. Those patients underwent GKS within 4 weeks after embolization. We analyzed retrospectively the angioarchitecture of the AVFs of BAVMs, selection of embolic materials for embolization, and treatment outcomes. RESULTS: The location of the AVFs was anterior (n = 7) or middle (n = 3) cerebral artery. Central and peripheral types of AVFs were found in seven and three patients, respectively. Nine AVFs were totally occluded by a single session of endovascular embolization, while one failed to be embolized because it was inaccessible to a microcatheter. Detachable coils (n = 6) or combination of liquid adhesives (n = 3) were selected to embolize the AVF. No significant periprocedural neurological complication was found. BAVMs were obliterated totally by subsequent GKS in six patients and partial occlusion was achieved in one, while three still awaited the effect of GKS. Mean imaging and clinical follow-up periods were 35 and 48 months, respectively. CONCLUSION: Early detection of the central type of AVF of BAVM prior to GKS may be difficult because of its overlapping with feeder, nidus, and/or venous drains or it being overlooked. Peripheral-type AVFs were usually evident prior to GKS, particularly those with proximal dilated venous drains. Endovascular embolization is an effective modality for managing these AVFs, which may be treated by GKS ineffectively.

Unusual giant intraspinal teratoma in an infant.

There are few cases of giant pediatric intraspinal teratoma. We report a case of a 4-month-old female baby with giant intraspinal teratoma. Magnetic resonance imaging (MRI) of the spine revealed a large intradural tumor from the C7 to S2 level, with solid, cystic, and fatty components. Partial surgical removal of the tumor showed pathology of a mature cystic teratoma. The imaging diagnosis of intraspinal teratoma included the location, solid and cystic component, and fatty content. The MR techniques adopted included gradient echo sequences as used to detect teeth or calcification. The difficulties in surgical resection of this case are also presented.

Improvements in the quantitative assessment of cerebral blood volume and flow with the removal of vessel voxels from MR perfusion images.

OBJECTIVE: To improve the quantitative assessment of cerebral blood volume (CBV) and flow (CBF) in the brain voxels from MR perfusion images. MATERIALS AND METHODS: Normal brain parenchyma was automatically segmented with the time-to-peak criteria after cerebrospinal fluid removal and preliminary vessel voxel removal. Two scaling factors were calculated by comparing the relative CBV and CBF of the segmented normal brain parenchyma with the absolute values in the literature. Using the scaling factors, the relative values were converted to the absolute CBV and CBF. Voxels with either CBV > 8 mL/100 g or CBF > 100 mL/100 g/min were characterized as vessel voxels and were excluded from the quantitative measurements. RESULTS: The segmented brain parenchyma with normal perfusion was consistent with the angiographic findings for each patient. We confirmed the necessity of dual thresholds including CBF and CBV for proper removal of vessel voxels. The scaling factors were 0.208 ± 0.041 for CBV, and 0.168 ± 0.037, 0.172 ± 0.037 for CBF calculated using standard and circulant singular value decomposition techniques, respectively. CONCLUSION: The automatic scaling and vessel removal techniques provide an alternative method for obtaining improved quantitative assessment of CBV and CBF in patients with thromboembolic cerebral arterial disease.

Transarterial detachable coil embolization of direct carotid-cavernous fistula: immediate and long-term outcomes.

BACKGROUND: Transarterial embolization is a standard method for management of direct carotid-cavernous fistula (DCCF). The purpose of this study was to report our experiences, and immediate and long-term outcomes of endovascular embolization of DCCFs by using detachable coils (DCs). METHODS: Over 8 years, 24 patients with 25 DCCFs underwent endovascular DC embolization. There were 15 men and nine women; age ranged from 8 to 82 years (mean, 39 years). Immediate and long-term angiographic as well as clinical outcomes after endovascular DC embolization were retrospectively analyzed. The number and the length of DCs used to occlude the fistula were also evaluated. RESULTS: Eighteen DCCFs were successfully occluded by single-session endovascular embolization with preservation of the parent artery. Retreatments by transvenous (n = 5) and/ or transorbital routes (n = 3) had to be performed in seven patients because of residual fistula (n = 4) or recurrent fistula (n = 4) occurring within 3 weeks after embolization. The average numbers and length of coils to occlude the fistulas were 14 (range, 2-31) and 189 cm (range, 16-756 cm), respectively. Four patients had small residual fistulas with spontaneous thrombosis on follow-up angiography. Three patients had transient cranial nerve impairment of the third (n = 1) or sixth (n = 2) nerve. There was no significant procedure-related neurological complication. The follow-up period was 3-48 months (mean, 19 months) CONCLUSION: Endovascular DC embolization of DCCFs was proved both efficacious and safe in managing high-flow fistulas with sustained angiographic and clinical effects, particularly in those DCCFs with small fistula track and/or cavernous sinus. However, retreatment via various routes may be necessary in some patients because of residual or recurrent fistulas.

Change in brain perfusion after extracranial-intracranial bypass surgery detected using the mean transit time of computed tomography perfusion.

BACKGROUND: Cerebral perfusion can be evaluated using a computed tomography (CT) scan by intravenous bolus injection of contrast media. The purpose of this study was to investigate the value of CT perfusion (CTP) in follow-up of extracranial-intracranial (EC-IC) bypass surgery. METHODS: We retrospectively reviewed pre- and postoperative CTP studies in 14 patients who received EC-IC bypass surgery because of cerebral arterial occlusion or stenosis. Brain areas showing prolongation of the mean transit time (MTT) were automatically identified and quantitatively measured. RESULTS: All 14 patients showed MTT prolongation in the preoperative CTP study. In 13 patients, a reduction in brain volume with MTT prolongation was noted during postoperative CTP. These 13 patients had a patent EC-IC anastomosis, and 42 ± 21% of the brain area with MTT prolongation returned to normal MTT during CTP 7 ± 4 days (range 2-13 days) after surgery. On clinical follow up of 41 ± 16 months (range 14-60 months), no stroke or transient ischemic attack was noted after bypass surgery in these 13 patients. The brain volume with MTT prolongation did not decrease in just one patient whose EC-IC anastomosis was not patent, and the patient suffered a minor stroke during surgery. CONCLUSION: Quantitative results for the brain area with MTT prolongation were positively correlated with improvement in brain perfusion shown on MTT, EC-IC bypass patency, and patient outcome.

Validation and absolute quantification of MR perfusion compared with CT perfusion in patients with unilateral cerebral arterial stenosis.

OBJECTIVE: The aim of the study was to assess absolute quantification of dynamic susceptibility contrast-enhanced magnetic resonance perfusion (MRP) comparing with computed tomography perfusion (CTP) in patients with unilateral stenosis. MATERIALS AND METHODS: We retrospectively post-processed MRP in 20 patients with unilateral occlusion or stenosis of >79% at the internal carotid artery or the middle cerebral artery (MCA). Absolute quantification of MRP was performed after applying the following techniques: cerebrospinal fluid removal, vessel removal, and automatic segmentation of brain to calculate the scaling factors to convert relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) values to absolute values. For comparison between MRP and CTP, we manually deposited regions of interest in bilateral MCA territories at the level containing the body of the lateral ventricle. RESULTS: The correlation between MRP and CTP was best for mean transit time (MTT) (r=0.83), followed by cerebral blood flow (CBF) (r=0.52) and cerebral blood volume (CBV) (r=0.43). There was no significant difference between CTP and MRP for CBV, CBF, and MTT on the lesion side, the contralateral side, the lesion-contralateral differences, or the lesion-to-contralateral ratios (P>0.05). The mean differences between MRP and CTP were as follows: CBV -0.57 mL/100g, CBF 2.50 mL/100g/min, and MTT -0.90 s. CONCLUSION: Absolute quantification of MRP is possible. Using the proposed method, measured values of MRP and CTP had acceptable linear correlation and quantitative agreement.