Publications by authors named "Ali Luqman"

16 Publications

  • Page 1 of 1

Performance Evaluation of Deep CNN-Based Crack Detection and Localization Techniques for Concrete Structures.

Sensors (Basel) 2021 Mar 1;21(5). Epub 2021 Mar 1.

Department of Computer Science and Software Engineering, College of Information Technology, UAEU, Al Ain 15551, United Arab Emirates.

This paper proposes a customized convolutional neural network for crack detection in concrete structures. The proposed method is compared to four existing deep learning methods based on training data size, data heterogeneity, network complexity, and the number of epochs. The performance of the proposed convolutional neural network (CNN) model is evaluated and compared to pretrained networks, i.e., the VGG-16, VGG-19, ResNet-50, and Inception V3 models, on eight datasets of different sizes, created from two public datasets. For each model, the evaluation considered computational time, crack localization results, and classification measures, e.g., accuracy, precision, recall, and F1-score. Experimental results demonstrated that training data size and heterogeneity among data samples significantly affect model performance. All models demonstrated promising performance on a limited number of diverse training data; however, increasing the training data size and reducing diversity reduced generalization performance, and led to overfitting. The proposed customized CNN and VGG-16 models outperformed the other methods in terms of classification, localization, and computational time on a small amount of data, and the results indicate that these two models demonstrate superior crack detection and localization for concrete structures.
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http://dx.doi.org/10.3390/s21051688DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7957757PMC
March 2021

Endovascular Thrombectomy of COVID-19-Related Large Vessel Occlusion: A Systematic Review and Summary of the Literature.

Curr Radiol Rep 2021 8;9(4). Epub 2021 Mar 8.

Department of Radiology, School of Medicine, Wayne State University/Detroit Medical Center, 4201 St. Antoine, DRH, 3L-8, Detroit, MI 48201 USA.

Purpose: Despite an overall reduction in the number of stroke cases presenting to hospitals during the COVID-19 pandemic, a remarkably high incidence of acute cerebrovascular disease associated with the infection has been reported. In this systematic review, we assess the neurological outcomes and complications of endovascular thrombectomy (EVT) for large vessel occlusions (LVO) in COVID-19 patients.

Methods: A literature search was performed in PubMed from December 1, 2019 through September 1st, 2020 using different combinations of suitable keywords. Ten studies reporting EVT outcomes and complications were identified. Two studies that included non-LVO pathologies and COVID-19 negative patients with the outcomes analysis were excluded. Patient demographics, comorbidities, anatomic thrombus location, neurological and angiographic outcomes were assessed.

Results: A total of 8 studies, in addition to our institutional case series, were ultimately included in this review. The mean age was 62.2 years, of which 67.6% were males. M1 segment involvement was the most commonly reported (53.8%) thrombus location. The mean NIHSS at presentation was 20.4 with no significant change at 24 h. Successful revascularization (TICI ≥ 2b) was achieved in 89%. Early proximal cerebral re-occlusion was reported in 6 patients (11%) and cerebral hemorrhage in 3 patients (4%). In hospital mortality was reported in 15 patients (28.8%).

Conclusion: Despite angiographically successful EVT of LVOs in the majority of patients, this literature analysis demonstrates overall poor outcomes and high mortality in COVID-19 patients post EVT. An unusual incidence of early intracerebral proximal arterial re-occlusion was notable.
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http://dx.doi.org/10.1007/s40134-021-00379-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7937782PMC
March 2021

A Moving Target? The Fate of Large Vessel Occlusion Strokes Pretreated with Intravenous Tissue Plasminogen Activator in the Era of Mechanical Thrombectomy.

World Neurosurg 2020 09 29;141:e447-e452. Epub 2020 May 29.

Wayne State University Departments of Neurosurgery and Neurology, Detroit, Michigan, USA.

Background: Although still recommended, using intravenous tissue plasminogen activator (IV-tPA) for large vessel occlusions (LVOs) has been questioned in the era of mechanical thrombectomy (MT). We sought to determine the impact of IV-tPA if used before MT.

Methods: We used a single-institution, prospectively maintained stroke database from July 2017 through June 2019. All patients undergoing MT with or without IV-tPA treatment for LVO with pretreatment computed tomography angiography (CTA) head and neck were included. We compared the initial CTA images of clot location and morphology to the angiographic findings visualized on the first injection before mechanical intervention.

Results: Eighty patients were included. About a third (33%) received IV-tPA before thrombectomy. Among patients receiving IV-tPA, significantly more, 29% versus 5.6% without IV-tPA, experienced distal clot migration or changes in morphology between first CTA acquisition and first angiographic run before thrombectomy (P = 0.006). On logistic regression IV-tPA was the only significant predictor of clot migration (P = 0.024). Of note, clot migration due to IV-tPA use was not associated with superior recanalization rates or outcomes in this analysis (P = 0.27). Original site clot resolution was noted in 8% (2/24) of patients who received IV-tPA; however, distal M4/5 embolic cutoffs were noted in both patients.

Conclusions: IV-tPA administration for LVO has a low rate of primary recanalization with risk of distal embolic phenomenon often still requiring MT. No significant changes in patient outcomes were noted in this study due to clot migration. Larger studies will be necessary to determine if IV-tPA plus MT truly benefits entire clot removal versus MT alone.
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http://dx.doi.org/10.1016/j.wneu.2020.05.187DOI Listing
September 2020

Distal transradial access in the anatomical snuffbox for balloon guide-assisted stentriever mechanical thrombectomy: Technical note and case report.

Brain Circ 2020 Jan-Mar;6(1):60-64. Epub 2020 Feb 18.

Department of Neurosurgery and Neurology, Wayne State University, Detroit, MI, USA.

Recent trends in neuroendovascular surgery have seen a rise in alternative access utilization. Social media feeds such as #RadialFirst or #RadialForNeuro are the beacons of a growing movement among more and more endovascular neurosurgeons, as they venture away from the traditional femoral access gravitating toward radial access. We have previously shown our distal radial access technique utilizing the snuffbox to be a reliable means of endovascular access and in addition to traditional ventral radial access provides access to the entire cerebrum. Stroke thrombectomy often encounters reticence from those who prefer transfemoral access over the radial access. Thrombectomy has been performed radially in a few series and only once previously in a case report of distal radial access for thrombectomy. Hesitance to adopt radial access for mechanical thrombectomy is often related to perceived increased access times and a lack of suitable balloon guide catheters for radial techniques. Here, we present one of the first descriptions of a distal transradial access with balloon guide flow arrest for stentriever thrombectomy.
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http://dx.doi.org/10.4103/bc.bc_22_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045539PMC
February 2020

Wideband RCS Reduction Using Coding Diffusion Metasurface.

Materials (Basel) 2019 Aug 23;12(17). Epub 2019 Aug 23.

School of Electronics and Information Engineering, Xi'an Jiaotong University, Xian 710049, China.

This paper presents a radar cross-section (RCS) reduction technique by using the coding diffusion metasurface, which is optimised through a random optimization algorithm. The design consists of two unit cells, which are elements '1' and '0'. The reflection phase between the two-unit cells has a 180° ± 37° phase difference. It has a working frequency band from 8.6 GHz to 22.5 GHz, with more than 9 dB RCS reduction. The monostatic RCS reduction has a wider bandwidth of coding diffusion metasurface as compared to the traditional chessboard metasurface. In addition, the bistatic performance of the designed metasurfaces is observed at 15.4 GHz, which shows obvious RCS reduction when compared to a metallic plate of the same size. The simulated and measured result shows the proficiency of the designed metasurface.
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http://dx.doi.org/10.3390/ma12172708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6747563PMC
August 2019

Snuff box radial access: A technical note on distal radial access for neuroendovascular procedures.

Brain Circ 2019 Jan-Mar;5(1):36-40. Epub 2019 Mar 27.

Department of Neurosurgery, Detroit Medical Center, Detroit, MI, USA.

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http://dx.doi.org/10.4103/bc.bc_2_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6458773PMC
March 2019

Effect of revascularization on cognitive outcomes in intracranial steno-occlusive disease: a systematic review.

Neurosurg Focus 2019 02;46(2):E14

3Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota.

OBJECTIVESteno-occlusive diseases of the cerebral vasculature have been associated with cognitive decline. The authors performed a systematic review of the existing literature on intracranial steno-occlusive disease, including intracranial atherosclerosis and moyamoya disease (MMD), to determine the extent and quality of evidence for the effect of revascularization on cognitive performance.METHODSA systematic search of PubMed/MEDLINE, the Thomson Reuters Web of Science Core Collection, and the KCI Korean Journal Database was performed to identify randomized controlled trials (RCTs) in the English-language literature and observational studies that compared cognitive outcomes before and after revascularization in patients with steno-occlusive disease of the intracranial vasculature, from which data were extracted and analyzed.RESULTSNine papers were included, consisting of 2 RCTs and 7 observational cohort studies. Results from 2 randomized trials including 142 patients with symptomatic intracranial atherosclerotic steno-occlusion found no additional benefit to revascularization when added to maximal medical therapy. The certainty in the results of these trials was limited by concerns for bias and indirectness. Results from 7 observational trials including 282 patients found some cognitive benefit for revascularization for symptomatic atherosclerotic steno-occlusion and for steno-occlusion related to MMD in children. The certainty of these conclusions was low to very low, due to both inherent limitations in observational studies for inferring causality and concerns for added risk of bias and indirectness in some studies.CONCLUSIONSThe effects of revascularization on cognitive performance in intracranial steno-occlusive disease remain uncertain due to limitations in existing studies. More well-designed randomized trials and observational studies are needed to determine if revascularization can arrest or reverse cognitive decline in these patients.
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http://dx.doi.org/10.3171/2018.11.FOCUS18517DOI Listing
February 2019

Retained Solitaire FR device after mechanical thrombectomy: Case review and management strategies.

Brain Circ 2018 Oct-Dec;4(4):185-187. Epub 2018 Dec 31.

Department of Neurosurgery, Wayne State University, Detroit, MI, USA.

Solitaire FR device is a Food and Drug Administration-approved device for mechanical thrombectomy. It has been tested in various clinical trials for its safety and efficacy. We report a case of inadvertent detachment of the Solitaire FR device at stent-stent wire interface while performing mechanical thrombectomy. We review a rare phenomenon of retained Solitaire FR stent retriever and discuss technique of avoidance and its management.
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http://dx.doi.org/10.4103/bc.bc_12_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6329211PMC
December 2018

Impact of expanding large vessel occlusion thrombectomy time-windows in inner city Detroit.

Brain Circ 2018 Apr-Jun;4(2):76-78. Epub 2018 Jun 29.

Department of Endovascular Neurosurgery, Detroit Medical Center, Detroit, MI 48201, USA.

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http://dx.doi.org/10.4103/bc.bc_9_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6126237PMC
June 2018

Bilateral Venous Sinus Stenosis: Idiopathic Intracranial Hypertension and Endovascular Venous Sinus Stenting: 2-Dimensional Operative Video.

Oper Neurosurg (Hagerstown) 2018 Sep;15(3):357

Department of Neurosurgery, Wayne State University, Detroit, Michigan.

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http://dx.doi.org/10.1093/ons/opx298DOI Listing
September 2018

Middle cerebral artery aneurysm rupture in a neonate with interrupted aortic arch: case report.

Childs Nerv Syst 2017 Jun 1;33(6):999-1003. Epub 2017 Mar 1.

Department of Neurological Surgery, University of Mississippi Medical Center, Batson's Children Hospital, 2500 N State St, Jackson, MS, 39216, USA.

Introduction: Arterial cerebral aneurysms in the neonatal population are rare, and while the association of interrupted aortic arch and intracranial aneurysm has been reported in the adult and pediatric population (three cases each), to date, it has not been reported in the neonate.

Case Report: We report the case of a 26-day-old girl who presented with a generalized seizure 2 weeks after undergoing congenital heart surgery. Head CT revealed diffuse SAH with a 1.7 × 2.9-cm frontal intra-parenchymal hematoma with subdural extension producing 3 mm of midline shift. CTA evidenced a 2-mm left MCA bifurcation aneurysm, and the patient was taken to the operating room for clipping. Twenty-four-hour post-operative head CT showed ventriculomegaly and an EVD was placed. It was removed 4 days later without the need for permanent CSF diversion, and after this, her hospital stay was uneventful and she was discharged home. At 25 months of age, she was meeting developmental milestones. At this time, she underwent further heart surgery and expired shortly thereafter due to cardiomyopathy.

Conclusion: Here, we report the successful treatment of a ruptured neonatal aneurysm, and the first known case associated with interrupted aortic arch. Given the time and presentation, this patient likely illustrates the role of hemodynamic factors in the rupture of neonatal aneurysms. In reviewing all of the reported cases of neonatal aneurysms, promptly securing the aneurysm by either open clipping, parent vessel occlusion, or endovascular coiling is strongly preferable to no surgical intervention.
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http://dx.doi.org/10.1007/s00381-017-3365-6DOI Listing
June 2017

Carotid cavernous fistulae occurring after the use of the Fogarty catheter in carotid surgery: a review.

Vasc Endovascular Surg 2013 Jul;47(5):359-67

Department of Neurosurgery, University of Mississippi Medical Center, Jackson, MS 39216, USA.

The Fogarty catheter represents a major advancement for the effective removal of distal thrombi during vascular surgery, including carotid endarterectomy (CEA). One complication related to its use is injury to the cavernous carotid artery with development of a carotid cavernous fistula (CCF). Including a recent case at our institution, 21 patients with a Fogarty-related CCF have been reported since 1967. We performed a detailed review of all Fogarty-related CCFs during the treatment of carotid occlusive disease. We suggest a management algorithm for post-CEA acute carotid occlusion.
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http://dx.doi.org/10.1177/1538574413487440DOI Listing
July 2013

Chemotherapy administration directly into the fourth ventricle in a nonhuman primate model.

J Neurosurg Pediatr 2012 May;9(5):530-41

Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.

Object: The authors hypothesized that chemotherapy infusions directly into the fourth ventricle might potentially play a role in treating malignant fourth ventricular tumors. The study tested the safety and pharmacokinetics of short- and long-term infusions of methotrexate into the fourth ventricle in a new nonhuman primate model.

Methods: Six rhesus monkeys underwent posterior fossa craniectomy and catheter insertion into the fourth ventricle. In Group I (3 animals), catheters were externalized, and lumbar drain catheters were placed simultaneously to assess CSF distribution after short-term methotrexate infusions. In 2 animals, methotrexate (0.5 mg) was infused into the fourth ventricle daily for 5 days. Serial CSF and serum methotrexate levels were measured. The third animal had a postoperative neurological deficit, and the experiment was aborted prior to methotrexate administration. In Group II (3 animals), catheters were connected to a subcutaneously placed port for subsequent long-term methotrexate infusions. In 2 animals, 4 cycles of intraventricular methotrexate, each consisting of 4 daily infusions (0.5 mg), were administered over 8 weeks. The third animal received 3 cycles, and then the experiment was terminated due to self-inflicted wound breakdown. All animals underwent detailed neurological evaluations, MRI, and postmortem histological analysis.

Results: No neurological deficits were noted after intraventricular methotrexate infusions. Magnetic resonance images demonstrated catheter placement within the fourth ventricle and no signal changes in the brainstem or cerebellum. Histologically, two Group I animals, one of which did not receive methotrexate, had several small focal areas of brainstem injury. Two Group II animals had a small (≤ 1-mm) focus of axonal degeneration in the midbrain. Intraventricular and meningeal inflammation was noted in 4 animals after methotrexate infusions (one from Group I and all three from Group II). In all Group II animals, inflammation extended minimally into brainstem parenchyma. Serum methotrexate levels were undetectable or negligible in both groups, ranging from 0.00 to 0.06 μmol/L. In Group I, the mean peak methotrexate level in fourth ventricle CSF exceeded that in the lumbar CSF by greater than 10-fold. Statistically significant differences between fourth ventricle and lumbar AUC (area under the concentration-time curve) were detected at peaks (p = 0.04) but not at troughs (p = 0.50) or at all time collection points (p = 0.12). In Group II, peak fourth ventricle CSF methotrexate levels ranged from 84.62 to 167.89 μmol/L (mean 115.53 ± 15.95 μmol/L [SD]). Trough levels ranged from 0.06 to 0.55 μmol/L (mean 0.22 ± 0.13 μmol/L).

Conclusions: Methotrexate can be infused into the fourth ventricle in nonhuman primates without clinical or radiographic evidence of injury. Observed inflammatory and other histological changes had no clinical correlate. This approach may have pharmacokinetic advantages over current treatment paradigms. Further experiments are warranted to determine if fourth ventricular chemotherapy infusions may benefit patients with malignant fourth ventricular tumors.
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http://dx.doi.org/10.3171/2012.1.PEDS11410DOI Listing
May 2012

Safety and pharmacokinetic analysis of methotrexate administered directly into the fourth ventricle in a piglet model.

J Neurooncol 2010 Dec 4;100(3):397-406. Epub 2010 May 4.

Department of Neurological Surgery, University of Miami Miller School of Medicine, and Miami Children's Hospital, Miami, FL 33155, USA.

We have developed a piglet model to assess chemotherapy administration directly into the fourth ventricle as a potential treatment for medulloblastoma and other malignant posterior fossa tumors. The objective of this study was to assess safety and pharmacokinetics after methotrexate infusions into the fourth ventricle. Catheters were inserted into the fourth ventricle and lumbar cistern in five piglets. Two milligrams of Methotrexate (MTX) was infused into the fourth ventricle on five consecutive days. Safety was assessed by neurological examination, 4.7 T MRI, and post-mortem pathological analysis. MTX levels in serum and cerebrospinal fluid (CSF) were measured, and area under the concentration-time curve (AUC) was calculated for CSF samples. No neurological deficits were caused by MTX infusions. One piglet died from complications of anesthesia induction for MRI scanning. MRI scans showed accurate catheter placement without signal changes in the brainstem or cerebellum. One piglet had asymptomatic ventriculomegaly. Pathological analysis demonstrated meningitis and choroid plexitis consisting predominantly of CD-3 positive T-lymphocytes in all piglets and a small focal area of subependymal necrosis in one. In all piglets, mean peak MTX level in fourth ventricular CSF exceeded that in lumbar CSF by greater than five-fold. Serum MTX levels were undetectable or negligible. Statistically significant differences between fourth ventricle and lumbar AUC were detected at peaks (P = 0.01) and at all collection time points (P = 0.01) but not at troughs (P = 0.36). MTX can be infused into the fourth ventricle without clinical or radiographic evidence of damage. An inflammatory response without clinical correlate is observed. Significantly higher peak MTX levels are observed in the fourth ventricle than in the lumbar cistern.
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http://dx.doi.org/10.1007/s11060-010-0210-0DOI Listing
December 2010

Pediatric spinal cord injury in infant piglets: description of a new large animal model and review of the literature.

J Spinal Cord Med 2010 ;33(1):43-57

Pediatric Critical Care (R-131), University of Miami School of Medicine, 1611 NW 12th Avenue, Miami, FL 33136, USA.

Objective: To develop a new, clinically relevant large animal model of pediatric spinal cord injury (SCI) and compare the clinical and experimental features of pediatric SCI.

Methods: Infant piglets (3-5 weeks old) underwent contusive SCI by controlled cortical impactor at T7. Severe complete SCI was induced in 6 piglets, defined as SCI with no spontaneous return of sensorimotor function. Eight piglets received incomplete SCI, which was followed by partial recovery. Somatosensory evoked potentials, magnetic resonance imaging, neurobehavioral function, and histopathology were measured during a 28-day survival period.

Results: Mean SCI volume (defined as volume of necrotic tissue) was larger after complete compared with incomplete SCI (387 +/- 29 vs 77 +/- 38 mm3, respectively, P < 0.001). No functional recovery occurred after complete SCI. After incomplete SCI, piglets initially had an absence of lower extremity sensorimotor function, urinary and stool retention, and little to no rectal tone. Sensory responses recovered first (1-2 days after injury), followed by spontaneous voiding, lower extremity motor responses, regular bowel movements, and repetitive flexion-extension of the lower extremities when crawling. No piglet recovered spontaneous walking, although 4 of 8 animals with incomplete injuries were able to bear weight by 28 days. In vivo magnetic resonance imaging was performed safely, yielded high-resolution images of tissue injury, and correlated closely with injury volume seen on histopathology, which included intramedullary hemorrhage, cellular inflammation, necrosis, and apoptosis.

Conclusion: Piglets performed well as a reproducible model of traumatic pediatric SCI in a large animal with chronic survival and utilizing multiple outcome measures, including evoked potentials, magnetic resonance imaging, functional outcome scores, and histopathology.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2853328PMC
http://dx.doi.org/10.1080/10790268.2010.11689673DOI Listing
May 2010