Time resolved imaging of contrast kinetics (TRICKS) MR angiography of arteriovenous malformations of head and neck

Diffusion tensor imaging parameters in differentiation recurrent breast cancer from post-operative changes in patients with breast-conserving surgery

AIM OF THE WORK

To investigate mean diffusivity (MD) and fractional anisotropy (FA) measured by diffusion tensor imaging (DTI) as complementary tools to differentiate recurrent breast cancer from post-operative changes in patients with breast-conserving surgery (BCS).

PATIENTS AND METHODS

Prospective study was conducted upon 30 patients with BCS that underwent DTI and dynamic contrast MR imaging. DTI was performed using an axial two-dimensional spin-echo echo-planar imaging sequence. The MD and FA of the lesions were calculated by 2 observers. A single pixel seed isotropic region of interest was placed in the solid part of the tumor on the axial color FA map guided by an enhanced part of the tumor. The final diagnosis was done by biopsy for all patients.

RESULTS

/s) used for differentiation between entities revealed sensitivity (76.9%, 92.3%), specificity (82.4%, 64.7%) and accuracy (80%, 76.7%) of both observers respectively. At ROC curve analysis of FA, the AUC was 0.82 and 0.75 by both observers. The threshold FA (0.82, 0.75) was used for differentiation between entities revealed sensitivity (92.3%, 76.9%), specificity (70.6%, 70.6%) and accuracy of (80.0%, 73.3%) of both observers respectively. There was a strong positive correlation of MD (r = 0.86) and FA (r = 0.73) of both observers. Combined analysis of FA and MD used for differentiation between entities had AUC (0.90, 0.88) revealed sensitivity (92.3%, 92.3%), specificity (82.4%, 70.6%) and accuracy of (86.7%, 80.0%) for both observers respectively.

CONCLUSIONS

Combined analysis of MD and FA of DTI may play an important role as a non-invasive method for differentiation recurrent breast cancer from post-operative changes in patients with BCS.

Effect of glycated hemoglobin index and mean arterial pressure on acute ischemic stroke prognosis after intravenous thrombolysis with recombinant tissue plasminogen activator

To determine whether glycated hemoglobin and mean arterial pressure (MAP) during thrombolysis are prognostic factors of intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke (AIS).A total of 125 AIS patients, who received rt-PA intravenous thrombolysis in our hospital, were included into the present study, and divided into good prognosis group and poor prognosis group. Univariate and multivariate logistic regression analyses were used to determine the prognostic factors of AIS treated by rt-PA thrombolysis, Spearman correlation analysis was used to analyze the correlation of the accumulated cigarette consumption in the smoking subgroup and glycated hemoglobin in the diabetic subgroup with the prognosis after intravenous thrombolysis and the symptomatic intracranial hemorrhage (sICH).Univariate analysis revealed that the interval from onset to thrombolysis, baseline National Institutes of Health Stroke Scale (NIHSS) score, MAP during thrombolysis and DRAGON score were prognostic factors. Multivariate logistic regression analysis revealed that baseline NIHSS score and MAP during thrombolysis were independent prognostic factors for rt-PA thrombolysis. Furthermore, the glycated hemoglobin index was positively correlated with the incidence of sICH.The NIHSS score before thrombolysis and MAP during thrombolysis were independent factors for the prognosis of AIS treated by thrombolysis. The higher the glycated hemoglobin index of diabetic patients, the more likely they are to develop sICH, the glycated hemoglobin index was negatively correlated with the prognosis after intravenous thrombolysis. The accumulated cigarette consumption was negatively correlated with the prognosis after intravenous thrombolysis.

Differentiation of Primary Central Nervous System Lymphoma From Glioblastoma: Quantitative Analysis Using Arterial Spin Labeling and Diffusion Tensor Imaging

OBJECTIVE

Differentiation of primary central nervous system lymphoma (PCNSL) from glioblastoma using arterial spin labeling perfusion and diffusion tensor imaging (DTI).

METHODS

We performed a prospective study of 31 patients with a provisional diagnosis of PCNSL and glioblastoma who underwent conventional magnetic resonance imaging, DTI, and arterial spin labeling of the brain. The tumor blood flow (TBF), mean diffusivity (MD) plus fractional anisotropy (FA) of the mass were measured. The final diagnosis was confirmed by pathological examination.

RESULTS

The TBF of PCNSL (26.41 ± 4.03 mL/100 g/minute) was significantly lower than that of glioblastoma (51.08 ± 3.9 mL/100 g/minute; P = 0.001). The TBF cutoff (35.73 mL/100 g/minute) used for differentiation showed area under the curve (AUC) of 0.93, accuracy of 95.2%, sensitivity of 91.7%, and specificity of 100%. The MD of PCNSL (0.87 ± 0.2X 10^-3 mm²/second) was significantly lower than that of glioblastoma (0.87 ± 0.2 × 10^-3 mm²/second; P = 0.01). The MD cutoff (0.935 × 10^-3 mm²/second) used for differentiation showed an AUC of 0.73 and accuracy of 66.7% and a sensitivity of 75% and specificity of 55.6%. The FA of PCNSL (0.253 ± 0.05) was significantly greater than that of glioblastoma (0.135 ± 0.06; P = 0.001). The FA cutoff (0.185) used for differentiation revealed an AUC of 0.944 and accuracy of 85.7% and a sensitivity of 83.3% and specificity of 88.9%. The combined TBF, MD, and FA cutoffs revealed an AUC of 0.96 and accuracy of 95.5% and a sensitivity of 83.3% and specificity of 100%.

CONCLUSION

The noninvasive imaging parameters using TBF and DTI might help in differentiating PCNSL from glioblastoma.

Imaging of Submandibular and Sublingual Salivary Glands

The submandibular and sublingual salivary glands are major salivary glands with a wide spectrum of pathologic conditions. The corresponding spaces along the floor of mouth have complex anatomy, best evaluated with cross-sectional imaging. The spectrum of diseases in these regions varies from simple infection to advanced malignancy, not just from the gland itself but also from the surrounding structures. The most common abnormalities in these spaces are inflammatory and infectious, and computed tomography is currently the most common imaging modality used. The anatomy of these spaces is much better depicted with MR; however, all the modalities have their unique roles.

A pilot study on adjunctive use of parametric colour-coded digital subtraction angiography in endovascular interventions of haemodialysis access

Background

Two-dimensional digital subtraction angiography (DSA) is the gold standard for angiographic evaluation of dysfunctional haemodialysis access. We aim to investigate the utility of parametric colour coded DSA in providing hemodynamic analysis during haemodialysis access interventions.

Methods

We retrospectively studied 20 patients who underwent access intervention and applied parametric colour-coding on selected DSA acquisitions before and after percutaneous transluminal angioplasty (PTA). The difference in time to peak (dTTP) contrast enhancement and time attenuation curve (TAC) of pre- and post-stenotic regions of interest (ROIs) were obtained and compared after treatment.

Results

Improvements were seen in mean percent of stenosis after PTA (p < 0.0001) for all cases. Median dTTP improved from 0.52 (IQR 0.26, 0.8) to 0.25 (IQR 0, 0.26) seconds (p = 0.001). Median 50% contrast washout time improved from 0.77 (IQR 0.39, 1.17) to 0.42 (IQR 0.23, 0.59) seconds (p = 0.031). Significant correlation was seen for dTTP vs. percent of stenosis (r = 0.723, p = 0.043) pre-PTA and for change in dTTP vs. percent change in stenosis post-PTA (r = 0.786, p = 0.021) for inflow lesions. Such correlation was however not seen in outflow lesions.

Conclusions

Adjunctive use of parametric colour-coded DSA may provide potentially useful hemodynamic information during vascular access interventions. Larger prospective studies are needed to validate our findings.

The relationship between oxidized low-density lipoprotein and related ratio and acute cerebral infarction

This study aimed to study the value of oxidized low-density lipoprotein (OX-LDL) and related ratio in the diagnosis of acute cerebral infarction and the classification of acute cerebral infarction.Of the 129 patients enrolled in this study, 94 patients with acute cerebral infarction were assigned to the case group, and 35 healthy subjects were enrolled as control group (n = 35). And then the case group were divided into large-artery atherosclerosis (LAA) group (n = 61) and small-artery occlusion (SAO) group (n = 33) according to the TOAST classification standard. Plasma OX-LDL levels were determined by enzyme-linked immunosorbent assay. OX-LDL/total cholesterol (OX-LDL/TC), OX-LDL/high-density lipoprotein (OX-LDL/HDL), OX-LDL/LDL were calculated.There were significant differences in OX-LDL, OX-LDL/TC, OX-LDL/HDL, and OX-LDL/LDL in patients with acute cerebral infarction and those in control group (P < .001). The area under the receiver-operating characteristic curve of OX-LDL and related ratio was >0.7 (P < .001). There was a slight positive correlation between OX-LDL/TC and National Institutes of Health Stroke Scale score at admission (r = 0.265, P = .039) in the LAA group.OX-LDL, OX-LDL/TC, OX-LDL/HDL, and OX-LDL/LDL were closely related to acute cerebral infarction, especially with large atherosclerotic cerebral infarction. OX-LDL/TC can reflect the severity of acute cerebral infarction for LAA, but it cannot predict the short-term prognosis of acute cerebral infarction.

Comparison of perioperative outcomes between endoscope-assisted technique and handheld acoustic Doppler for perforator identification in fasciocutaneous flaps

The endoscopic technique has been utilized to harvest muscle flaps and detect perforators of fasciocutaneous flaps. This study aimed to compare the perioperative outcomes between the endoscope-assisted technique and handheld acoustic Doppler for perforator identification in fasciocutaneous flaps.This retrospective case-control study included patients who underwent fasciocutaneous flap reconstruction for traumatic soft tissue defects. In the case group, perforator identification was assisted by the endoscope-assisted technique. In the control group, age- and sex-matched patients received handheld acoustic Doppler to detect perforators. Perioperative outcomes, flap characteristics, and postoperative complications were compared.There were 12 patients in the case group and 12 in the control group. Compared with the control group, the case group had a significantly shorter length of donor-site wounds (9 cm vs 12 cm, P = .023) and a significantly smaller proportion of patients receiving skin grafting at the donor sites (0% vs 41.7%, P = .037). The case group had a longer operative time, but the difference was not statistically significant (180 minutes vs 150 minutes, P = .367). The amount of blood loss, the time length of postoperative drainage, and complications did not significantly differ between the 2 groups.The endoscope-assisted technique for perforator identification of fasciocutaneous flaps provided less donor-site morbidity and a significantly shorter length of donor-site wounds than the conventional handheld acoustic Doppler, which suggests that this technique could be a valuable alternative when a precise design is indicated.

Prediction of venous malformations with localized intravascular coagulopathy with diffusion-weighted magnetic resonance imaging

Background

Venous malformations may be complicated by localized intravascular coagulopathy which is a serious condition with hematological sequel. Prediction of localized intravascular coagulopathy is mandatory for prompt anticoagulation therapy. Laboratory and routine magnetic resonance imaging can predict localized intravascular coagulopathy in venous malformations; however, the results are variable.

Purpose

To predict venous malformations with localized intravascular coagulopathy with diffusion-weighted magnetic resonance imaging.

Material and methods

A retrospective analysis was performed on 55 patients (34 male, 21 female aged 14–64 years: mean 39 years) with venous malformations that underwent diffusion-weighted magnetic resonance imaging. The apparent diffusion coefficient value of venous malformations was calculated.

Results

The mean apparent diffusion coefficient value of venous malformations with localized intravascular coagulopathy (n = 26) (1.28 ± 0.18 × 10−3 mm2/s) was significantly different ( P = 0.001) from venous malformations without localized intravascular coagulopathy (n = 29) (1.60 ± 0.18 × 10−3 mm2/s). When apparent diffusion coefficient value of 1.454 × 10−3 mm2/s was used as a threshold value for the prediction of venous malformations with localized intravascular coagulopathy, the best result was obtained with an accuracy of 83.6%, sensitivity of 84.6%, specificity of 82.8%, and area under the curve of 0.895. The apparent diffusion coefficient value of venous malformations was correlated with D-dimer level ( r = −0.59, P = 0.006) and fibrinogen level ( r = 0.73, P = 0.001).

Conclusion

The apparent diffusion coefficient value is a non-invasive imaging parameter that can be used to predict venous malformations with localized intravascular coagulopathy.

Inter-observer agreement of the Coronary Artery Disease Reporting and Data System (CAD-RADSTM) in patients with stable chest pain

Purpose

To assess inter-observer variability of the Coronary Artery Disease - Reporting and Data System (CAD-RADS) for classifying the degree of coronary artery stenosis in patients with stable chest pain.

Material and methods

A prospective study was conducted upon 96 patients with coronary artery disease, who underwent coronary computed tomography angiography (CTA). The images were classified using the CAD-RAD system according to the degree of stenosis, the presence of a modifier: graft (G), stent (S), vulnerable plaque (V), or non-diagnostic (n) and the associated coronary anomalies, and non-coronary cardiac and extra-cardiac findings. Image analysis was performed by two reviewers. Inter-observer agreement was assessed.

Results

There was excellent inter-observer agreement for CAD-RADS (k = 0.862), at 88.5%. There was excellent agreement for CAD-RADS 0 (k = 1.0), CAD-RADS 1 (k = 0.92), CAD-RADS 3 (k = 0.808), CAD-RADS 4 (k = 0.826), and CAD-RADS 5 (k = 0.833) and good agreement for CAD-RADS 2 (k = 0.76). There was excellent agreement for modifier G (k = 1.0) and modifier S (k = 1.0), good agreement for modifier N (k = 0.79), and moderate agreement for modifier V (k = 0.59). There was excellent agreement for associated coronary artery anomalies (k = 0.845), non-coronary cardiac findings (k = 0.857), and extra-cardiac findings (k = 0.81).

Conclusions

There is inter-observer agreement of CAD-RADS in categorising the degree of coronary arteries stenosis, and the modifier of the system and associated cardiac and extra-cardiac findings.

A Factor Increasing Venous Contamination on Bolus Chase Three-dimensional Magnetic Resonance Imaging: Charcot Neuroarthropathy

Background

The study aimed to evaluate the ratio of venous contamination in diabetic cases without foot lesion, with foot lesion and with Charcot neuroarthropathy (CN).

Materials and Methods

Bolus-chase three-dimensional magnetic resonance (MR) of 396 extremities of patients with diabetes mellitus was analyzed, retrospectively. Extremities were divided into three groups as follows: diabetic patients without foot ulcer or Charcot arthropathy (Group A), patients with diabetic foot ulcers (Group B) and patients with CN accompanying diabetic foot ulcers (Group C). Furthermore, amount of venous contamination classified as no venous contamination, mild venous contamination, and severe venous contamination. The relationship between venous contamination and extremity groups was investigated.

Results

Severe venous contamination was seen in Group A, Group B, and Group C, 5.6%, 15.2%, and 34.1%, respectively. Statistically significant difference was seen between groups with regard to venous contamination.

Conclusion

Venous contamination following bolus chase MR was higher in patients with CN.

MR imaging of neoplastic and non-neoplastic lesions of the brain and spine in neurofibromatosis type I

The aim of this work is to review the MR imaging of neoplastic and non-neoplastic lesions of the brain and spine in neurofibromatosis type I. Neoplastic lesions are optic pathway gliomas, brain stem gliomas, other gliomas of the brain, and peripheral nerve sheath tumors. Structural changes in the brain include unidentified bright objects, macrocephaly, and enlarged corpus callosum. Bony dysplasia changes as sphenoid ridge dysplasia, spinal scalloping, dural ectasia, and meningoceles. Vasculopathy and cortical cerebral and cerebellar malformations of the brain have been reported.

Angioarchitecture of Hereditary Arteriovenous Malformations

This article describes three hereditary conditions known to be associated with arteriovenous malformation (AVM), along with their clinical and imaging features and angiographic angioarchitecture. Hereditary hemorrhagic telangiectasia, capillary malformation-AVM (CM-AVM), and PTEN tumor hamartoma syndrome are conditions with autosomal dominant inheritance, caused by mutations in different molecular pathways, which frequently present with symptomatic AVMs. Imaging biomarkers, including sites of predilection, angioarchitecture, and tissue overgrowth patterns, are helpful in identifying these patients and selecting appropriate treatment.

Clinical value of classification of venous malformations with contrast-enhanced MR Angiography

Aim

To classify venous malformations based on contrast-enhanced MR angiography that may serve as a basis for treatment plan.

Patients and methods

A retrospective analysis was performed in 58 patients with venous malformations who underwent contrast-enhanced MR angiography. Venous malformations were classified according to their venous drainage into: type I, isolated malformation without peripheral drainage; type II, malformation that drains into normal veins; type III, malformation that drains into dilated veins; and type IV, malformation that represents dysplastic venous ectasia. Image analysis was done by two reviewers. Intra and inter-observer agreement of both reviewers and intra-class correlation was done.

Results

The intra-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for the first reviewer ( k = 0.83, 95% CI = 0.724–0.951, P = 0.001) and substantial for the second reviewer ( K = 0.79, 95% CI = 0.656-0.931, P = 0.001). The inter-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for both reviewers at the first time ( K = 0.96, 95% CI = 0.933–1.000, P = 0.001) and second time ( k = 0.81, 95% CI = 0.678–0.942, P = 0.001). There was high intra-class correlation of both reviewers for single measure ( ICC = 0.85, 95% CI = 0.776–0.918, P = 0.001) and for average measures ( ICC = 0.96, 95% CI = 0.933–0.978, P = 0.001).

Conclusion

Contrast-enhanced MR angiography classification of venous malformations may be a useful, simple and reliable tool to accurately classify venous malformation and this topographic classification helps for better management strategy.

An epidural arteriovenous fistula studied with time-resolved imaging of contrast kinetics (TRICKS) sequence

We describe the use of time-resolved MR angiography in the diagnosis of cervical epidural arteriovenous fistula before final diagnosis and embolization was achieved by digital subtraction angiography. A 42-year-old woman was referred to us because of headache and dizziness, in addition to radiculopathy of the right superior limb. Angiographic examinations documented a direct high-flow arteriovenous fistula between the right vertebral artery and the cervical epidural venous plexus. The point of fistula was located in the upper third of the cervical segment below the C2 arch. Time-resolved MR angiography might add important information in case of suspected arteriovenous fistula, helpful both for therapeutic decisions and follow-up.

High-Performance Upconversion Nanoprobes for Multimodal MR Imaging of Acute Ischemic Stroke

Multimodal magnetic resonance (MR) imaging, including MR angiography (MRA) and MR perfusion (MRP), plays a critical role in the diagnosis and surveillance of acute ischemic stroke. However, these techniques are hindered by the low T1 relaxivity, short circulation time, and high leakage rate from vessels of clinical Magnevist. To address these problems, nontoxic polyethylene glycol (PEG)ylated upconversion nanoprobes (PEG-UCNPs) are synthesized and first adopted for excellent MRA and MRP imaging, featuring high diagnostic sensitivity toward acute ischemic stroke in high-resolution imaging. The investigations show that the agent possesses superior advantages over clinical Magnevist, such as much higher relaxivity, longer circulation time, and lower leakage rate, which guarantee much better imaging efficiency. Remarkably, an extremely small dosage (5 mg Gd kg(-1) ) of PEG-UCNPs provides high-resolution MRA imaging with the vascular system delineated much clearer than the Magnevist with clinical dosage as high as 108 mg Gd kg(-1) . On the other hand, the long circulation time of PEG-UCNPs enables the surveillance of the progression of ischemic stroke using MRA or MRP. Once translated, these PEG-UCNPs are expected to be a promising candidate for substituting the clinical Magnevist in MRA and MRP, which will significantly lengthen the imaging time window and improve the overall diagnostic efficiency.

Imaging of connective tissue diseases of the head and neck

We review the imaging appearance of connective tissue diseases of the head and neck. Bilateral sialadenitis and dacryoadenitis are seen in Sjögren's syndrome; ankylosis of the temporo-mandibular joint with sclerosis of the crico-arytenoid joint are reported in rheumatoid arthritis and lupus panniculitis with atypical infection are reported in patients with systemic lupus erythematosus. Relapsing polychondritis shows subglottic stenosis, prominent ear and saddle nose; progressive systemic sclerosis shows osteolysis of the mandible, fibrosis of the masseter muscle with calcinosis of the subcutaneous tissue and dermatomyositis/polymyositis shows condylar erosions and autoimmune thyroiditis. Vascular thrombosis is reported in antiphospholipid antibodies syndrome; cervical lymphadenopathy is seen in adult-onset Still's disease, and neuropathy with thyroiditis reported in mixed connective tissue disorder. Imaging is important to detect associated malignancy with connective tissue disorders. Correlation of the imaging findings with demographic data and clinical findings are important for the diagnosis of connective tissue disorders.

Supra-aortic low-dose contrast-enhanced time-resolved magnetic resonance (MR) angiography at 3 T: comparison with time-of-flight MR angiography and high-resolution contrast-enhanced MR angiography

BACKGROUND

Low-dose, time-resolved, contrast-enhanced, magnetic resonance angiography (TR-CEMRA) has been described previously; however, a comparative study between low dose TR-CEMRA and time-of-flight MRA (TOF-MRA) in the diagnosis of supra-aortic arterial stenosis has not yet been published.

PURPOSE

To demonstrate the feasibility and effectiveness of low-dose TR-CEMRA compared with TOF-MRA, using high-resolution contrast-enhanced MRA (HR-CEMRA) as the reference standard.

MATERIAL AND METHODS

This prospective study consisted of 30 consecutive patients. All patients underwent TOF-MRA of the neck and circle of Willis and supra-aortic HR-CEMRA, followed by supra-aortic low-dose TR-CEMRA. Gadoterate meglumine (Gd-DOTA, Dotarem(®), Guerbet, Roissy CdG Cedex, France) was injected at a dose of 0.1 mmol/kg for HR-CEMRA, followed by a 0.03 mmol/kg bolus for low-dose TR-CEMRA. Three readers evaluated the assessibility and image quality, and then two readers classified each stenosis into the following categories: normal (0-30%), mild stenosis (31-50%), moderate (51-70%), severe (71-99%), and occlusion.

RESULTS

TR-CEMRA and HR-CEMRA showed a greater number of assessable arterial segments than TOF-MRA (P < 0.01). For TR-CEMRA, 29 cases showed within or better than the diagnostic range, whereas all 30 cases were in the diagnostic range for TOF-MRA and HR-CEMRA. For evaluation of stenosis in a total of 743 arterial segments, both TR-CEMRA and TOF-MRA results agreed with those of HR-CEMRA in 729 segments (98.1%), with excellent inter-observer agreement of TR-CEMRA; stenosis was overestimated in nine segments (1.2%) and underestimated in five segments (0.7%). For diagnosis of stenosis using 30% as the cut-off value on HR-CEMRA, the sensitivity and specificity were 88.2% and 99.3%, respectively, for the TR-CEMRA procedure, versus 94.1% and 99.6%, respectively, for TOF-MRA.

CONCLUSION

Low-dose TR-CEMRA is feasible and effective in the diagnosis of supra-aortic arterial stenosis, and could be more useful option than TOF-MRA.

The role of time-resolved imaging of contrast kinetics (TRICKS) magnetic resonance angiography (MRA) in the evaluation of head-neck vascular anomalies: a preliminary experience

OBJECTIVES

In this preliminary report, we describe our experience with time-resolved imaging of contrast kinetics-MR angiography (TRICKS-MRA) in the assessment of head-neck vascular anomalies (HNVAs).

METHODS

We prospectively studied six consecutive patients with clinically suspected or diagnosed HNVAs. All of them underwent TRICKS-MRA of the head and neck as part of the routine for treatment planning. A digital subtraction angiography (DSA) was also performed.

RESULTS

TRICKS-MRA could be achieved in all cases. Three subjects were treated based on TRICKS-MRA imaging findings and subsequent DSA examination. In all of them, DSA confirmed the vascular architecture of HNVAs shown by TRICKS-MRA. In the other three patients, a close follow up to assess the evolution of the suspected haemangioma was preferred.

CONCLUSIONS

TRICKS sequences add important diagnostic information in cases of HNVAs, helpful for therapeutic decisions and post-treatment follow up. We recommend TRICKS-MRA use (if technically possible) as part of routine MRI protocol for HNVAs, representing a possible alternative imaging tool to conventional DSA.

Advances and innovations in brain arteriovenous malformation surgery

Arteriovenous malformations (AVMs) of the brain are very complex and intriguing pathologies. Since their initial description by Luschka and Virchow in the middle of the 19th century, multiple advances and innovations have revolutionized their management and surgical treatment. Here, we review the historical landmarks in the surgical treatment of AVMs and then illustrate the most recent and futuristic technologies aiming to improve outcomes in AVM surgeries. In particular, we examine potential advances in patient selection, imaging, surgical technique, neuroanesthesia, and postoperative neuro-rehabilitation and quantitative assessments. Finally, we illustrate how concurrent advances in radiosurgery and endovascular techniques might present new opportunities to treat AVMs more safely from a surgical perspective.

Role of computed tomography angiography in the diagnosis of vascular stenosis in head and neck microvascular free flap reconstruction

The aim of this study was to evaluate the role of computed tomography angiography (CTA) in the diagnosis of vascular stenosis at the vascular pedicle of head and neck microvascular free flaps. A prospective study was done of 65 consecutive patients (49 male, 16 female; mean age 55 years) who had undergone head and neck microvascular free flap reconstruction. All patients underwent 64-slice CTA of the carotid artery. Post-processing with volume rendering reconstruction of CTA images was done. There was excellent inter-observer agreement (weighted kappa=0.82, 95% confidence interval (CI) 0.74-0.93) in grading of the degree of vascular stenosis. The true sensitivity of CTA for diagnosis of stenosis of the vascular pedicle to the flap was 63% (95% CI 63-100%). Patients with failed flaps showed complete occlusion (n=2) on CTA and underwent a replacement flap procedure. Patients with failing flaps showed severe stenosis (n=6) of the vascular pedicle on CTA and underwent revision surgery. There was no change in the degree of stenosis on follow-up CTA for patients with moderate stenosis (n=9). CTA is a reliable, non-invasive, high-quality imaging tool for the diagnosis and grading of vascular stenosis of the vascular pedicle of head and neck microvascular free flaps.