Contrast-enhanced ultrasound features as potential biomarker for prediction of breast cancer recurrence.

Purpose To investigate the associations between contrast-enhanced ultrasound imaging features and disease recurrence among patients with locally advanced breast cancer treated with neoadjuvant chemotherapy. Materials and Methods In the study, pre- and post-neoadjuvant chemotherapy contrast-enhanced ultrasound images of 43 patients with breast cancer were retrospectively analysed. Post-acquisition image processing involved the placement of freehand-drawn regions of interest, followed by the generation of blood flow kinetics representing blood volume and velocity for these regions of interest. Qualitative and quantitative contrast-enhanced ultrasound parameters were compared to predict recurrence, and receiver operating characteristic analysis was used to evaluate predictive ability. Results Among the 43 patients, 10 (23%) exhibited disease recurrence (median [range]: 27 [4-68] months). Post-neoadjuvant chemotherapy peak enhancement, wash-in area under the curve, wash-out area under the curve, and wash-in and wash-out area under the curve (p=0.003, p=0.004, p=0.026, and p=0.014, respectively) differed between the no-recurrence and recurrence groups. The area under the receiver operating characteristic curve (0.88; 95% confidence interval: 0.75-1.00) for post-neoadjuvant chemotherapy peak enhancement was the highest among the contrast-enhanced ultrasound parameters, with a cut-off of 13.33 arbitrary units. Conclusion Higher peak enhancement on post-neoadjuvant chemotherapy contrast-enhanced ultrasound images were associated with recurrence in women with locally advanced breast cancer and is a potential biomarker of tumour recurrence.

Clinical Effectiveness of Artificial Disc Replacement in Comparison With Anterior Cervical Discectomy and Fusion in the Patients With Cervical Myelopathy: Systematic Review and Meta-analysis.

OBJECTIVE: Cervical myelopathy (CM) describes the compressive cervical spinal cord state, often accompanied by serious clinical condition, by herniated disc or hypertrophied spurs or ligament. Anterior cervical discectomy and fusion (ACDF) has been frequently employed as conventional surgical solution for this CM despite its inherent biomechanical handicap. Alternatively, an artificial disc replacement (ADR) preserves cervical motion while still decompressing the spinal canal and neural foramen. This analysis elaborated to clarify the potential benefits of ADR application to CM over ACDF from the conglomerated results of the past references. METHODS: A literature search was performed using MEDLINE, Embase, Cochrane review, and KMbase databases from the studies published until March 2023. Six studies (3 randomized controlled study [RCTs] and 3 non-RCTs) were included in a qualitative and quantitative synthesis. Data were extracted and analyzed using a random effects model to obtain effect size and its statistical significance. Quality assessment and evidence level were established in accordance with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. RESULTS: Among 6 studies, 2 studies showed that ADR group achieved significantly better clinical improvement than the ACDF group, while the rest 4 studies revealed no significant difference. A meta-analysis showed better clinical outcomes with or without statistical significance. The level of evidence was low because of inconsistency and imprecision. CONCLUSION: ADR was superior or at least, not inferior to ACDF in terms of functional recovery. However, its application to the CM patients is merely empowered with weak strength due to low level of evidence.

Clinical Effectiveness of Posterior Annular Targeted Ablative Decompression as an Alleviative Intervention for Lumbosacral Discogenic Pain: Systematic Review and Meta-analysis.

BACKGROUND: Various percutaneous intradiscal procedures have been implemented to manage lumbosacral discogenic pain. But most of these procedures simply end up manipulating the central nucleus pulposus or the inner annulus, instead of accessing the posterior outer annulus where the actual, major pain generators exist. Thus, more localized percutaneous techniques, specifically derived to address the pathologic tissues creeped between the torn, posterior annulus and hyperplastic sinuvertebral nerve, have been devised. However, the clinical effectiveness of these "more" accurate procedures is still skeptical. OBJECTIVES: This study has investigated whether the posterior annular targeted decompression was a useful method to treat lumbosacral discogenic pain in terms of pain control or functional improvement. STUDY DESIGN: A systematic review and meta-analysis. SETTING: Primary clinic and tertiary referral center. PATIENTS: Published past references that have dealt with the issue of clinical effectiveness after the posterior annular targeted decompression as a treatment of discogenic pain in terms of pain control and functional improvement. METHODS: A literature search was performed using MEDLINE, EMBASE, Cochrane Review, and KoreaMed databases from the studies published until December 2022. After reviewing titles, abstracts, and full texts of 65 studies during the initial database search, 12 studies were included in a qualitative synthesis, and 9 trials from 8 studies were in quantitative meta-analysis. Data, including pain and functional scores, were extracted and were analyzed using a random effects model to obtain statistical significance of mean difference. Quality assessment and evidence level were established in accordance with the Grading of Recommendations Assessment, Development and Evaluation methodology. RESULTS: Finally, 12 single-arm studies without the control group were included. All studies showed significant pain reduction and functional improvement from a 1-month to 1-year follow-up period. A meta-analysis showed significant reduction in pain scores at 1 month, 3 months, 6 months, and 1 year and functional scores at 1 month, 6 months, and 1 year. The level of evidence was very low because of the nonrandomized study design and inconsistency and imprecision across studies. LIMITATIONS: Only single-arm studies comparing clinical results before and after treatment without the control group were analyzed. The statistical and clinical heterogeneity, due to different aspect of techniques across the studies and a relatively small number of patients, reduced the evidence level. CONCLUSIONS: Comprehensive reviews of selected articles revealed posterior annular targeted decompression could be recommended as treatment option in the patients with discogenic pain who have failed in attaining clinical improvement after the conservative managements under weak evidential strength support. KEY WORDS: Discogenic pain, minimal invasive technique, percutaneous targeted disc decompression, systematic review, meta-analysis.

Associations between angiogenic factors and intravoxel incoherent motion-derived parameters in diffusion-weighted magnetic resonance imaging of breast cancer.

ABSTRACT: Intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (MRI) can be used to estimate perfusion-related parameters, but these parameters may differ, based on the curve-fitting algorithm used for IVIM. Microvessel density (MVD) and vascular endothelial growth factor (VEGF) status are used as angiogenic factors in breast cancer. We aimed to investigate the relationship between MVD, VEGF, and intravoxel incoherent motion (IVIM)-derived parameters, obtained by 4 curve-fitting algorithms, in patients with invasive breast cancers.This retrospective study investigated IVIM-derived parameters, D (ie, tissue diffusivity), D∗ (ie, pseudodiffusivity), and f (ie, perfusion fraction), of 55 breast cancers, using 10 b values (range, 0-800 s/mm2) and 4 curve-fitting algorithms: algorithm 1, linear fitting of D and f first, followed by D∗; algorithm 2, linear fitting of D and f and nonlinear fitting of D∗; algorithm 3, linear fitting of D and f, linear fitting of D∗, and ignoring D contribution for low b values; and algorithm 4, full nonlinear fitting of D, f, and D∗. We evaluated whole-tumor histograms of D, f, and D∗ for their association with MVD and VEGF.D∗10, D∗25, D∗50, D∗mean, D∗75, D∗90, f10, and f25, derived using algorithm 3, were associated with VEGF expression (P = .043, P = 0.012, P = .019, P = .024, P = .044, P = .041, P = .010, and P = .005, respectively). However, no correlation existed between MVD and IVIM-derived parameters.Perfusion-related IVIM parameters obtained by curve-fitting algorithm 3 may reflect VEGF expression.

Brain metastasis with subtype conversion in a patient with male breast cancer: A case report.

RATIONALE: Brain metastasis of male breast cancer is extremely rare, and the pathological changes between the primary tumor and the metastatic brain tumor have not been reported. Herein, we report for the first time a case of male breast cancer with metastasis to the parietal lobe with subtype conversion after metastasis. PATIENT CONCERNS: we describe a 45-year-old male patient admitted for an incidentally found brain tumor after a motorcycle accident. The patient had been treated for breast cancer 5 years previously. The primary tumor was an invasive ductal carcinoma classified as pT1N1M0 with hormone receptor positivity (estrogen receptor ++, progesterone receptor +++, human epidermal growth factor receptor-type2 (HER2) +) and was treated with surgery, adjuvant chemotherapy, radiation therapy and endocrine therapy (tamoxifen). DIAGNOSES: Magnetic resonance imaging revealed a well enhanced focal solid tumor in the right parietal lobe (5.0 × 4.2 cm in size), Immunohistochemical staining revealed cerebral metastases of breast cancer with HER2 subtype conversion (estrogen receptor +++, progesterone receptor +++, HER2 -). INTERVENTIONS: The patient was successfully treated with surgery and whole brain irradiation (3 Gy × 10 fractions). OUTCOMES: There was no additional complication after the surgery and the patient transferred to oncology department for chemotherapy. 2 years later, he had gamma knife radiosurgery due to the recurred brain lesion and after that he discontinued the treatment and opted for hospice care. LESSONS: Male breast cancer with metastasis to the brain is an extremely rare condition. Although a few similar cases have been reported, subtype conversion in similar cases has not been reported. Therefore, we report this case of a male patient with brain metastasis of invasive ductal carcinoma with HER2 status conversion after metastasis.

Diagnostic Role of Contrast-enhanced Ultrasound in the Discrimination of Malignant Portal Vein Thrombosis in Patients With Hepatocellular Carcinoma.

BACKGROUND/AIM: To investigate the accuracy of contrast-enhanced ultrasound (CEUS) in differentiating benign and malignant portal vein thrombosis (PVT) complicating hepatocellular carcinoma (HCC), compared to diffusion-weighted magnetic resonance imaging (DWI). PATIENTS AND METHODS: Forty-nine patients with HCC who had PVT were enrolled. The quantitative and qualitative parameters of CEUS were analysed. We examined the diagnostic performance of CEUS compared with DWI. The relationships between CEUS parameters and biomarkers were also assessed. RESULTS: All qualitative CEUS parameters (e.g., arterial-phase enhancement, washout in the venous phase, vessel occlusion, and expansion) were significantly more common in malignant thrombosis than in benign thrombosis (p<0.05). Among the quantitative CEUS parameters, increased area under the time-intensity curve, prolonged time for full width at half maximum, and prolonged rise time were observed in malignant thrombosis, compared to benign thrombosis (p<0.05). CEUS and DWI performed similarly in discriminating between malignant and benign thrombi (p>0.05). Several CEUS parameters exhibited significant correlations with the tumour marker and stage (p<0.05). CONCLUSION: CEUS was useful for characterisation of PVT and showed a consistent high diagnostic accuracy, compared to DWI.

Triple-negative breast cancer: Pretreatment magnetic resonance imaging features and clinicopathological factors associated with recurrence.

PURPOSE: We aimed to investigate the magnetic resonance imaging (MRI) features and clinicopathologic factors with recurrence of triple-negative breast cancer (TNBC). PATIENTS AND METHODS: We identified 281 patients with 288 surgically confirmed TNBC lesions who underwent pretreatment MRI between 2009 and 2015. The presence of intratumoral high signal on T2-weighted images, high-signal rim on diffusion-weighted images (DWI), and rim enhancement on the dynamic contrast-enhanced MRI and clinicopathological data were collected. Cox proportional analysis was performed. RESULTS: Of the 288 lesions, 36 (12.5%) recurred after a median follow-up of 18 months (range, 3.6-68.3 months). Rim enhancement (hazard ratio [HR] = 3.15; 95% confidence interval [CI] = 1.01, 9.88; p = .048), and lymphovascular invasion (HR = 2.73, 95% CI = 1.20, 6.23; p = .016) were independently associated with disease recurrence. While fibroglandular volume, background parenchymal enhancement, intratumoral T2 high signal, and high-signal rim on DWI, were not found to be risk factors for recurrence. CONCLUSION: Pretreatment MRI features may help predict a high risk of recurrence in patients with TNBC.

Atrophic Changes and Diffusion Abnormalities of Affected Trigeminal Nerves in Trigeminal Neuralgia Using 7-T MRI.

BACKGROUND: Magnetic resonance imaging (MRI) has been widely used for visualizing trigeminal nerves in trigeminal neuralgia. OBJECTIVE: To assess atrophy and diffusion abnormalities of affected trigeminal nerves in trigeminal neuralgia with 7-T MRI. METHODS: In this prospective study, 14 patients (mean age 49 years; range 31-64 years) with trigeminal neuralgia underwent 7-T MRI. We measured trigeminal nerve volumes along their course through the pontocerebellar cistern. We also evaluated fractional anisotropy (FA) and quantitative anisotropy (QA) values within cisternal segment and pontine nuclei of the affected-side and unaffected-side trigeminal nerves, using diffusion tensor imaging (DTI). Associations between DTI metrics and Barrow Neurological Institute (BNI) pain scores were examined. RESULTS: The volumes were significantly smaller for the affected trigeminal nerves (33.83 ± 23.12 mm3) than for the unaffected ones (47.76 ± 32.48 mm3; p = 0.008). Cisternal segment FA and QA values were significantly lower in affected trigeminal nerves than in unaffected ones. However, DTI measurements in the pontine nuclei revealed no significant differences between affected-side and unaffected-side trigeminal nerves. No DTI metrics significantly correlated with BNI pain scores. CONCLUSION: Our results suggest that 7-T MRI allows identifications of atrophy and diffusion abnormalities of trigeminal nerves in trigeminal neuralgia.

Contrast-Enhanced Ultrasound for Early Prediction of Response of Breast Cancer to Neoadjuvant Chemotherapy.

PURPOSE: To evaluate the time-intensity curve (TIC) parameters on contrast-enhanced ultrasound (CEUS) for early prediction of the response of breast cancer to neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: This prospective study included 41 patients with breast cancer. CEUS was performed before and after the first cycle of NAC. TIC parameters were analyzed for different regions of interest (ROIs). ROI 1 targeted the hotspot area of greatest enhancement, ROI 2 delineated the area of hyperenhancement, ROI 3 included the entire tumor on grayscale ultrasound, and ROI 4 encircled the normal parenchyma. The TIC perfusion values for ROI 1, 2, and 3 were divided by the ROI 4 value. RESULTS: 11 (26.8 %) of the 41 patients showed a good response (Miller-Payne score 4 or 5) and 30 (73.2 %) showed a minor response (Miller-Payne score 1, 2, or 3). There were significant differences in the wash-out area under the curve, the wash-in and wash-out areas under the curve on ROI 1/4 after the first cycle of NAC, pre-NAC mean transit time local (mTTl) on ROI 2/4, and pre-NAC mTTl on ROI 3/4 between good and minor responders (area under the receiver-operating characteristic curve > 0.70, p < 0.05). CONCLUSION: Some TIC parameters obtained by CEUS may allow prediction of the response of breast cancer to NAC at a very early time point.

7 Tesla magnetic resonance imaging of caudal anterior cingulate and posterior cingulate cortex atrophy in patients with trigeminal neuralgia.

The cingulate cortex (CC) is a brain region that plays a key role in pain processing, but CC abnormalities are not unclear in patients with trigeminal neuralgia (TN). The purpose of this study was to determine the central causal mechanisms of TN and the surrounding brain structure in healthy controls and patients with TN using 7 Tesla (T) magnetic resonance imaging (MRI). Whole-brain parcellation in gray matter volume and thickness was assessed in 15 patients with TN and 16 healthy controls matched for sex, age, and regional variability using T1-weighted imaging. Regions of interest (ROIs) were measured in rostral anterior CC (rACC), caudal anterior CC (cACC) and posterior CC (PCC). We also investigated associations between gray matter volume or thickness and clinical symptoms, such as pain duration, Barrow Neurologic Institute (BNI) scores, offender vessel, and medications, in patients with TN. The cACC and PCC exhibited gray matter atrophy and reduced thickness between the TN and control groups. However, the rACC did not. Cortical volumes were negatively correlated with pain duration in transverse and inferior temporal areas, and thickness was also negatively correlated with pain duration in superior frontal and parietal areas. The cACC and PCC gray matter atrophy occurred in the patients with TN, and pain duration was associated with frontal, parietal, and temporal cortical regions. These results suggest that the cACC, PCC but not the rACC are associated with central pain mechanisms in TN.

7.0 Tesla MRI tractography in patients with trigeminal neuralgia.

7.0 Tesla (T) high-resolution diffusion tensor imaging (DTI) can supply information on changing microstructures in cranial nerves. We investigated DTI parameters and the feasibility of DTI criteria for diagnosing trigeminal neuralgia (TN). In this study, 14 patients (28 hemispheres) of mean age 49.0 years (range, 31-64) with TN underwent DTI using 7.0 TMRI. We compared fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) of affected-side and unaffected-side trigeminal nerves using DTI. We examined associations between DTI parameters and clinical characteristics for patients with TN. In patients with TN, affected sides showed significantly decreased FA and significantly increased MD, and RD compared with unaffected sides of trigeminal nerves. Nuclei were not significantly different among patients with TN. Barrow Neurological Institute (BNI) pain scores did not correlate with affected sides. 7.0 T DTI was useful for detecting neurovascular compression in patients with TN. The increased signal-to-noise ratio provided by 7 T MRI should be advantageous for increasing spatial resolution to detect microstructure changes to trigeminal nerves in patients with TN.

Optical inactivation of the anterior cingulate cortex modulate descending pain pathway in a rat model of trigeminal neuropathic pain created via chronic constriction injury of the infraorbital nerve.

PURPOSE: The anterior cingulate cortex (ACC) plays a critical role in the initiation, development, and maintenance of neuropathic pain. Recently, the effects of optical stimulation on pain have been investigated, but the therapeutic effects of optical stimulation on trigeminal neuralgia (TN) have not been clearly shown. Here, we investigated the effects of optical inhibition of the ACC on TN lesions to determine whether the alleviation of pain affects behavior performance and thalamic neuron signaling. MATERIALS AND METHODS: TN lesions were established in animals by generating a chronic constriction injury of the infraorbital nerve, and the animals received injections of AAV-hSyn-eNpHR3.0-EYFP or a vehicle (phosphate-buffered saline [PBS]) in the ACC. The optical fiber was fixed into the ipsilateral ACC after the injection of adeno-associated virus plasmids or vehicle. Behavioral testing, consisting of responses to an air puff and cold allodynia, was performed, and thalamic neuronal activity was monitored following optical stimulation in vivo. Optical stimulation experiments were executed in three steps: during pre-light-off, stimulation-light-on, and post-light-off states. The role of the optical modulation of the ACC in response to pain was shown using a combination of optical stimulation and electrophysiological recordings in vivo. RESULTS: Mechanical thresholds and facial cold allodynia scores were significantly improved in the TN lesion group during optical stimulation compared to those in the control group. Thalamic neuronal activity, consisting of the firing rate (spikes/s) and burst rate (bursts/s), was also decreased during optical stimulation. CONCLUSION: Reciprocal optical inhibition of the ACC can alleviate pain-associated behavior and decrease abnormal thalamic sensory neuron activity in the trigeminal neuropathic rat model. The descending pain pathway can modulate thalamic neurons from the ACC following optical stimulation.

Comparison of 7T and 3T MRI in patients with moyamoya disease.

Magnetic resonance imaging and magnetic resonance angiography (MRI/MRA) are widely used for evaluating the moyamoya disease (MMD). This study compared the diagnostic accuracy of 7Tesla (T) and 3T MRI/MRA in MMD. In this case control study, 12 patients [median age: 34years; range (10-66years)] with MMD and 12 healthy controls [median age: 25years; range (22-59years)] underwent both 7T and 3T MRI/MRA. To evaluate the accuracy of MRI/MRA in MMD, five criteria were compared between imaging systems of 7T and 3T: Suzuki grading system, internal carotid artery (ICA) diameter, ivy sign, flow void of the basal ganglia on T2-weighted images, and high signal intensity areas of the basal ganglia on time-of-flight (TOF) source images. No difference was observed between 7T and 3T MRI/MRA in Suzuki stage, ICA diameter, and ivy sign score; while, 7T MRI/MRA showed a higher detection rate in the flow void on T2-weighted images and TOF source images (p<0.001). Receiver operating characteristic curves of both T2 and TOF criteria showed that 7T MRI/MRA had higher sensitivity and specificity than 3T MRI/MRA. Our findings indicate that 7T MRI/MRA is superior to 3T MRI/MRA for the diagnosis of MMD in point of detecting the flow void in basal ganglia by T2-weighted and TOF images.

Intravoxel incoherent motion (IVIM)-derived parameters in diffusion-weighted MRI: Associations with prognostic factors in invasive ductal carcinoma.

PURPOSE: To investigate relationships between intravoxel incoherent motion (IVIM) metrics of invasive ductal carcinoma of the breast and prognostic factors. MATERIALS AND METHODS: This retrospective study included a total of 82 masses from 72 patients who underwent 3T breast magnetic resonance imaging (MRI) and diffusion-weighted imaging. IVIM metrics of tissue diffusivity (Dslow ), pseudodiffusivity (Dfast ), and perfusion fraction (Dpf ) were measured using histogram analysis for whole lesion volumes. We evaluated relationships between IVIM metrics and prognostic factors or subtypes of invasive ductal carcinoma. RESULTS: The Dslow 50th , 75th , and 90th percentile metrics were reduced in the estrogen receptor (ER)-positive group compared with the ER-negative group (individually, P = 0.044, 0.024, 0.045). Additionally, the Dslow 75th percentile value was a significant differentiator of histologic grade, tumor subtype, and Ki-67 grouping (individually, P = 0.024, 0.049, 0.016). The Dpf mean, 75th , 90th percentile, skewness, and kurtosis metrics were correlated with the size of ductal carcinoma in situ (DCIS) component (individually, P = 0.034, 0.032, 0.027, 0.013, 0.013). CONCLUSION: The Dslow metrics differentiated between ER-positive and -negative groups, and the Dpf metrics were associated with the size of the DCIS component. LEVEL OF EVIDENCE: 4 J. MAGN. RESON. IMAGING 2017;45:1394-1406.

Variability in Observer Performance Between Faculty Members and Residents Using Breast Imaging Reporting and Data System (BI-RADS)-Ultrasound, Fifth Edition (2013).

BACKGROUND: Ultrasonography (US) is a useful tool for breast imaging, yet is highly operator-dependent. OBJECTIVES: We evaluated inter-observer variability and performance discrepancies between faculty members and radiology residents when describing breast lesions, by the fifth edition of breast imaging reporting and data system (BI-RADS)-US lexicon, and then attempted to identify whether inter-observer variability could be improved after one education session. PATIENTS AND METHODS: In total, 50 malignant lesions and 70 benign lesions were considered in our retrospective study. Two faculty members, two senior residents, and two junior residents separately assessed the US images. After the first assessment, the readers received one education session, and then reassessed the images in a random order. Inter-observer variability was measured using the kappa coefficient (κ). Performance discrepancy was evaluated by receiver operating characteristic (ROC) curves. RESULTS: For the faculty members, fair-to-good agreement was obtained in all descriptors and final assessment, while for residents, poor-to-moderate agreement was obtained. The areas under the ROC curves were 0.78 for the faculty members, 0.59 for the senior residents, and 0.52 for the junior residents, respectively. Diagnostic performance was significantly higher in the faculty members than the senior and junior residents (P = 0.0001 and < 0.0001, respectively). After one education session, the agreement in the final assessment was one level higher in the faculty members and senior residents, yet in the senior residents, the degree of agreement was still only fair. Moreover, in the junior residents, there was no improvement. CONCLUSION: Investigative assessment of breast US by residents is inadvisable. We recommend continued professional resident training to improve the degree of agreement and performance.

Suppressed GABAergic signaling in the zona incerta causes neuropathic pain in a thoracic hemisection spinal cord injury rat model.

OBJECTIVE: Suppression of the gamma-aminobutyric acid (GABA)ergic activity of the zona incerta (ZI) reportedly plays a role in neuropathic pain after spinal cord injury (SCI). A reduction in GABAergic signaling in the ZI of a thoracic hemisection-SCI rat model has been suggested, but not clearly demonstrated. Accordingly, our objective was to investigate whether GABAergic signals influence SCI-induced neuropathic pain. METHODS: In vivo, we recorded and compared single-unit, neuronal activity between hemisection-SCI and sham-operated rat models. Furthermore, we analyzed neuronal activity in both models following treatment with either a GABAA receptor agonist (muscimol) or antagonist (bicuculline). RESULTS: Rats that underwent hemisection SCI exhibited reduced hindpaw withdrawal thresholds, latencies, and decreased ZI neuronal activity compared with sham-operated controls. Importantly, muscimol treatment increased, whereas bicuculline decreased, the firing rates of the ZI neurons. The muscimol treated, hemisection-SCI rats also exhibited increased hindpaw withdrawal thresholds and latencies. CONCLUSIONS: These data provide evidence that neuropathic pain after SCI is caused by decreased GABAergic signaling in the ZI. Furthermore, our data demonstrate that infusion of a GABAergic drug into the ZI could restore its inhibitory action and improve neuropathic pain behaviors.

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.

Automatic left and right lung separation using free-formed surface fitting on volumetric CT.

This study presents a completely automated method for separating the left and right lungs using free-formed surface fitting on volumetric computed tomography (CT). The left and right lungs are roughly divided using iterative 3-dimensional morphological operator and a Hessian matrix analysis. A point set traversing between the initial left and right lungs is then detected with a Euclidean distance transform to determine the optimal separating surface, which is then modeled from the point set using a free-formed surface-fitting algorithm. Subsequently, the left and right lung volumes are smoothly and directly separated using the separating surface. The performance of the proposed method was estimated by comparison with that of a human expert on 44 CT examinations. For all data sets, averages of the root mean square surface distance, maximum surface distance, and volumetric overlap error between the results of the automatic and the manual methods were 0.032 mm, 2.418 mm, and 0.017 %, respectively. Our study showed the feasibility of automatically separating the left and right lungs by identifying the 3D continuous separating surface on volumetric chest CT images.

Diagnostic accuracy of 64-slice multidetector CT angiography for detection of in-stent restenosis of vertebral artery ostium stents: comparison with conventional angiography.

BACKGROUND: There are very few reports assessing in-stent restenosis (ISR) after vertebral artery ostium (VAO) stents using multidetector computed tomography (MDCT). PURPOSE: To compare the diagnostic accuracy of computed tomography angiography (CTA) using 64-slice MDCT with digital subtraction angiography (DSA) for detection of significant ISR after VAO stenting. MATERIAL AND METHODS: The study evaluated 57 VAO stents in 57 patients (39 men, 18 women; mean age 64 years [range, 48-90 years]). All stents were scanned with a 64-slice MDCT scanner. Three sets of images were reconstructed with three different convolution kernels. Two observers who were blinded to the results of DSA assessed the diagnostic accuracy of CTA for detecting significant ISR (≥50% diameter narrowing) of VAO stents in comparison with DSA as the reference standard. The sensitivity, specificity, positive and negative predictive values, and accuracy were calculated. RESULTS: Of the 57 stents, 46 (81%) were assessable using CTA, while 11 (19%) were not. No stents with diameters ≤2.75 mm were assessable. DSA revealed 13 cases of significant ISR in all stents. The respective sensitivity, specificity, positive and negative predictive values, and accuracy were 92%, 82%, 60%, 97%, and 84% for all stents. On excluding the 11 non-assessable stents, the respective values were 88%, 95%, 78%, 97%, and 93%. Of the 46 CTA assessable stents, eight significant ISRs were diagnosed on DSA. Seven of eight patients with significant ISR by DSA were diagnosed correctly with CTA. The area under the receiver-operating characteristic curve (AUC) was 0.87 for all stents and 0.91 for assessable stents, indicating good to excellent agreement between CTA and DSA for detecting significant ISR after VAO stenting. CONCLUSION: Sixty-four-slice MDCT is a promising non-invasive method of assessing stent patency and can exclude significant ISR with high diagnostic values after VAO stenting.

In vivo evaluation of carotid artery stents using multi-detector-row computed tomography angiography: comparison of 3 kernels.

OBJECTIVE: The objective of this study was to assess the lumen visibility of carotid artery stents using multi-detector-row computed tomography (MDCT) angiography; compare medium-smooth, medium-sharp, and sharp kernels; and correlate these results to those of digital subtraction angiography (DSA). METHODS: We retrospectively evaluated 52 stents from 51 patients who underwent 16- and 64-slice MDCT angiography. Lumen diameters were measured 3 times by 2 neuroradiologists, and artificial luminal narrowing was calculated. To assess detection of in-stent restenosis (>50%), 2 neuroradiologists evaluated all MDCT and DSA images. RESULTS: Excellent intraobserver and interobserver agreements were obtained for the lumen diameter measurements (P < 0.001). Lumen diameter visibility improved, and artificial luminal narrowing decreased from the medium-smooth kernel to the sharp kernel. Visual estimation of all CT angiography using the 3 kernels showed high accuracy for detection of in-stent restenosis (>50%), compared with DSA. CONCLUSIONS: Computed tomography angiography using a sharp kernel allows for more accurate assessment of lumen visibility after carotid artery stenting.