Naoko Saito

Boston University, Boston, Massachusetts, United States

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Publications (74)94.05 Total impact

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    ABSTRACT: We present an extremely rare case of an aberrant course of the petrous internal carotid artery (ICA) associated with the ipsilateral occipital artery arising from the cervical ICA, a combination not previously reported by magnetic resonance (MR) angiography. The patient was a 53-year-old woman with no symptoms related to the anomalous ICA. Source images and partial maximum-intensity-projection images of MR angiography are useful in diagnosing these variations. Source images and curved multiplanar reconstruction images of computed tomography angiography are important for the accurate evaluation of reduced arterial diameter and the relationship between the anomalous artery and petrous bone.
    Surgical and radiologic anatomy : SRA. 02/2015;
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    ABSTRACT: Extremely rarely, the ophthalmic artery (OphA) arises from the A1 segment of the anterior cerebral artery (ACA). Discovery of this anomalous OphA during angiography or surgery has been reported in several patients. We report a case in which an OphA of ACA origin was diagnosed by magnetic resonance (MR) angiography and confirmed by selective cerebral angiography. To our knowledge, this is the first report of this variation with MR angiography. Careful observation of MR angiographic images is important for detecting rare arterial variations. Partial maximum-intensity-projection images are useful in identifying tiny anomalous arteries on MR angiography.
    Surgical and Radiologic Anatomy 02/2015; · 1.33 Impact Factor
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    ABSTRACT: Moyamoya disease is a rare progressive cerebrovascular steno-occlusive disease associated with different variations of the cerebral arteries. We evaluated the types and prevalence of such variations among patients with moyamoya disease. In our institution during the past seven years, we diagnosed 72 patients (24 male, 48 female; aged 6 to 75 years, mean, 42 years) with moyamoya disease by magnetic resonance (MR) angiography using either a 3-Tesla or one of two 1.5-T imagers and a standard time-of-flight technique without contrast media. An experienced neuroradiologist retrospectively reviewed the images. There were 15 cerebral arterial variations in 13 of 72 patients with moyamoya disease (18.1%), including four basilar artery fenestrations, three ophthalmic arteries arising from the middle meningeal artery, two intracranial vertebral artery fenestrations, two persistent first cervical intersegmental arteries, two persistent trigeminal arteries, one extracranial origin of the posterior inferior cerebellar artery, and one persistent stapedial artery. Although our number of patients was small, moyamoya disease was frequently associated with variations of the cerebral arteries, especially fenestrations in the vertebrobasilar system and persistent trigeminal artery.
    The neuroradiology journal. 12/2014; 27(6):697-701.
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    ABSTRACT: The several types of agenesis of the internal carotid artery (ICA) are classified based on the aplastic segment of the ICA and types of collateral circulation. On magnetic resonance angiography, we incidentally found an extremely rare case in which the patient had 2 types of collateral circulation-anastomosis between the paraclinoid and supraclinoid segments of the contralateral ICA and anastomosis between the tip of the basilar artery and the posterior communicating artery. This is the first report of a case of ICA agenesis with 2 such types of collateral circulation.
    Surgical and Radiologic Anatomy 10/2014; · 1.33 Impact Factor
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    ABSTRACT: Anastomosis of the carotid-anterior cerebral artery (ACA) is a rare anomalous vessel that arises from the internal carotid artery (ICA) at the level of the ophthalmic artery and takes an infraoptic and prechiasmatic path to anastomose with the ACA. It has known right-sided predominance. We report the case of an 83-year-old man with a left carotid-ACA anastomosis that was diagnosed by magnetic resonance (MR) angiography from the neck to the head during investigation of transient left hemiplegia. The right ICA was occluded at its origin. Our literature search revealed only six reported cases of left carotid-ACA anastomoses. We believe ours is the first case diagnosed by MR angiography.
    Surgical and Radiologic Anatomy 08/2014; · 1.33 Impact Factor
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    ABSTRACT: Penetrating neck injuries are commonly related to stab wounds and gunshot wounds in the United States. The injuries are classified by penetration site in terms of the three anatomical zones of the neck. Based on this zonal classification system, penetrating injuries to the head and neck have traditionally been evaluated by conventional angiography and/or surgical exploration. In recent years, multidetector-row computed tomography (CT) angiography has significantly improved detectability of vascular injuries and extravascular injuries in the setting of penetrating injuries. CT angiography is a fast and minimally invasive imaging modality to evaluate penetrating injuries of the head and neck for stable patients. The spectrum of penetrating neck injuries includes vascular injury (extravasation, pseudoaneurysm, dissection, occlusion, and arteriovenous fistula), aerodigestive injury (esophageal and tracheal injuries), salivary gland injury, neurologic injury (spinal canal and cerebral injuries), and osseous injury, all of which can be evaluated using CT angiography. Familiarity with the complications and imaging characteristics of penetrating injuries of the head and neck is essential for accurate diagnosis and optimal treatment.
    The Keio Journal of Medicine 06/2014;
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    ABSTRACT: Clinical manifestations of sickle cell disease (SCD) can affect the orbit with prior reports describing changes in the lacrimal gland potentially related to chronic vaso-occlusion. The purpose of this study was to evaluate lacrimal gland volumes and quantifiable shifts in MR-relaxation times in patients with SCD.
    Journal of Computer Assisted Tomography 05/2014; · 1.60 Impact Factor
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    ABSTRACT: PURPOSE/AIM To review the current CT and MR perfusion imaging methods in head and neck cancer. Also to describe various clinical applications of CT and MR perfusion imaging in head and neck cancer. CONTENT ORGANIZATION 1. Review of the current CT and MR perfusion imaging techniques being used to evaluate head and neck cancers including pros and cons for each technique: A)dynamic contrast enhanced CT perfusion, B)MR perfusion, i)With intravenous contrast: a)dynamic susceptibility contrast enhanced (DSC), b)dynamic contrast enhanced (DCE), ii)Without intravenous contrast: a)arterial spin labeling (ASL), b)intravoxel incoherent motion (IVIM). 2. Review of the clinical applications of CT and MR perfusion imaging in head and neck cancer. A)differentiation of tumor histology, B)monitoring tumor perfusion, C)prediction of tumor response to the treatment, D)evaluation of post-treatment tumor change, E)prediction and evaluation of treatment effect in the normal tissues. SUMMARY The major teaching points are: 1. Understanding of various techniques of CT and MR perfusion for head and neck cancers. 2. Understanding microvascular blood supply to the tumor as well as normal tissue that affects treatment response and side-effects. 3. Perfusion information may predict tumor response to various treatments, locoregional control, and treatment-related normal tissue injuries.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: PURPOSE/AIM High-grade glioma is the most common brain malignancy in adults. Concurrent temozolomide and radiotherapy is the new standard of care for patients with glioblastoma multiforme (GBM). Assessment of treatment response using conventional MRI is complicated by pseudoprogression and pseudoresponse. The purpose of this exhibit is: 1. To review treatments for GBM. 2. To summarize concepts and illustrate pseudoprogression and pseudoresponse on conventional MR imaging. 3. To discuss and illustrate the use of advanced MRI and PET in differentiating true progression from pseudoprogression CONTENT ORGANIZATION 1. Review of GBM treatments. 2. Definition and pathophysiology of pseudoprogression and psueodrtesponse. 3. Review of post-treatment conventional MRI: A. Recurrence B. Pseudoprogression C. Radionecrosis D. Pseudoresponse 4. Review criteria for tumor response after treatment and revised time-to-chemotherapy dependent criteria. 5. Discussion of imaging modalities to differentiate pseudoprogression from recurrence: A. Conventional MRI B. MR spectroscopy C. MR perfusion D. FDG-PET/CT SUMMARY Radiologists should be aware of the imaging features on post-treatment of GBM on conventional MRI. Having an understanding of the concepts and the utilization of advanced MRI and PET imaging techniques can help differentiate pseudopregression from true progression.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: Although identification of human papilloma virus (HPV) status in oropharyngeal squamous cell carcinoma (OPSCC) is essential in predicting treatment response, no imaging modality can currently determine whether a tumor is HPV-related. In this retrospective study, 26 patients with OPSCC confined to the lateral wall or the base of tongue underwent neck magnetic resonance imaging, using T1-, T2- and diffusion-weighted imaging (DWI). Apparent diffusion coefficients (ADCs) in a region of interest covering the largest available primary tumor area of OPSCC on a single slice of the ADC map were calculated using two b values (0 and 1,000 s/mm(2)). Mean and minimum ADCs were compared with HPV status, using p16 immunohistochemistry as a surrogate marker for HPV infection. Mean and minimum ADCs for HPV(+) OPSCC were significantly lower than those for HPV(-) OPSCC. A cut-off value of mean ADC for HPV(+) OPSCC of 1.027 × 10(-3) mm(2)/s yielded sensitivity and specificity of 83.33 and 78.57 %, respectively. In conclusion, the present study indicates that ADC could be used to predict HPV status in patients with OPSCC.
    Archives of Oto-Rhino-Laryngology 07/2013; 271(5). · 1.61 Impact Factor
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    ABSTRACT: Purpose: We evaluated the prevalence and imaging characteristics of ring-shaped lateral ventricular nodules (RSLVNs) detected by postcontrast brain magnetic resonance (MR) imaging. Materials and Methods: We retrospectively reviewed cranial MR images of 1,241 patients who underwent contrast-enhanced brain imaging between January 1, 2008 and March 31, 2011, excluded images of inadequate quality of 130 patients, and ultimately analyzed images of 1,111 patients (544 male, 567 female). We assessed location, shape, and signal intensity of RSLVNs on T1-weighted (T1WIs), T2-weighted (T2WIs), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted (DWIs) images and characteristics of contrast enhancement. Results: In 5 patients, we found 6 RSLVNs (0.45%), four in the frontal horn and two in the roof of the body. Three RSLVNs were round, two were oval, and one was lobular on axial images. All 6 RSLVNs were isointense with adjacent brain parenchyma on T1WI, T2WI, and DWI but slightly hyperintense on FLAIR images; none showed enhancement on postcontrast MR imaging. Five nodules serially examined (range, 8 to 24 months) showed no interval changes. Conclusions: Our MR imaging findings of a 0.45% prevalence of RSLVNs shows they are not so rare as previously reported. Except for configuration, all nodules had similar intensity, and none showed contrast enhancement. Absence of changes during the follow-up period seemed to indicate that the nodules have no clinical significance. However, their clear differentiation avoids unnecessary surgery.
    Magnetic Resonance in Medical Sciences 05/2013; · 1.04 Impact Factor
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    ABSTRACT: OBJECTIVE: To study age-related characteristics of T1 and T2 relaxation times and volume of the major salivary glands. METHODS: Thirty-five subjects (0.5-87 years old) with normal salivary glands were imaged with mixed turbo spin-echo pulse sequences at 1.5-T magnetic resonance units. Bilateral parotid, submandibular, and sublingual glands were segmented manually. Histograms for each salivary gland were generated and modeled with Gaussian functions for every parameter. RESULTS: Seventy parotid glands, 52 submandibular glands, and 50 sublingual glands were segmented and the histograms were analyzed. The parotid gland exhibited shorter-peak T1s and longer-peak T2s relative to the submandibular and sublingual glands. The peak T2s for all glands showed a minimum value between 2 and 4 years of age and increased monotonically thereafter. From birth to early adulthood, all glands increased in size logarithmically. CONCLUSION: Age-related relaxo-volumetric changes of the major salivary glands show clear T2 and volumetric age-related patterns for all glands.
    Journal of computer assisted tomography 03/2013; 37(2):272-278. · 1.38 Impact Factor
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    ABSTRACT: INTRODUCTION: A persistent dorsal ophthalmic artery (OA) is a rare variation that originates from the cavernous segment of the internal carotid artery (ICA) and enters the orbit via the superior orbital fissure (SOF). Occasionally, the OA also arises from the middle meningeal artery (MMA) and enters the orbit via the SOF. These two major variations of the OA have not been well described by magnetic resonance (MR) angiography. We evaluated their prevalence on MR angiography at 3 T. METHODS: We retrospectively reviewed our database of MR angiographic images obtained using a 3 T imager. Of images of 846 patients, we evaluated those of 826 patients (1,652 OAs) with special attention to OA origin and its course into the orbit. We excluded images of the 20 because quality was insufficient to assess. RESULTS: We found 7 (0.42 %) persistent dorsal OAs among 1,652 OAs (right/left, 6/1; male/female, 3/4). Twenty-four (1.45 %) OAs arose from the MMA (right/left/bilateral, 11/5/4; male/female, 10/10), three of which also demonstrated a small normally branching OA. In one patient, we observed both right persistent dorsal OA and left OA arising from the MMA. CONCLUSIONS: Per OA, the prevalence of persistent dorsal OA was 0.42 % and of OA arising from the MMA, 1.45 %, with a tendency toward right-side predominance. OA arising from the MMA can be seen bilaterally; preprocedural knowledge of this variation is important because of the danger associated with endovascular procedures of the external carotid system when the OA arises from the MMA.
    Anatomia Clinica 02/2013; · 1.33 Impact Factor
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    ABSTRACT: INTRODUCTION: The origin of the vertebral artery (VA) varies, though most VAs enter the transverse foramen (TF) of the sixth cervical vertebra. On computed tomography (CT) angiographic images, we evaluated the prevalence of variations of both VA origin and its level of entry into the TF. METHODS: We retrospectively reviewed CT angiographic images of 2,287 patients obtained using either of two 64-slice multidetector CT scanners. All patients were Japanese and underwent scanning from the aortic arch to the intracranial region; most had or were suspected of having cerebrovascular diseases. RESULTS: The left VA (LVA) arose from the aorta between the left common carotid artery and left subclavian artery in 94 patients (4.1 %) and in other variations in 44 patients (1.9 %). The right VA (RVA) arose from the extreme proximal segment of the right subclavian artery in 72 patients (3.1 %) and in other variations in 14 patients (0.6 %). The LVA entered the sixth TF in 2,127 patients (93.0 %), and the RVA entered the sixth TF in 2,146 patients (93.8 %). Anomalous origin and anomalous entry level into the TF correlated strongly. CONCLUSIONS: The total prevalence of variation in the origin of the LVA was 6.0 % and of the RVA, 3.8 %. The total prevalence of variation in entry level into the TF was 7.0 % for the LVA and 6.2 % for the RVA. Recognition and reporting of these variations is important in interpreting CT angiography to prevent complications during surgery of the aortic arch or lower neck.
    Neuroradiology 01/2013; · 2.37 Impact Factor
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    ABSTRACT: To investigate the clinicoradiological manifestations of craniofacial bone infarcts in patients with sickle cell disease (SCD). After institutional review board approval, we identified 85 SCD patients who underwent head and neck magnetic resonance imaging (MRI) during a period of 5 years (January 1, 2004-December 31, 2008) and reviewed their clinical presentations and radiological findings. Of 40 subjects with headache or facial pain, 6 (5 males, 1 female; age range, 2-22 years; 5 Hb SS, 1 Hb SC) were diagnosed with acute bone infarct by MRI. Of these 6, 4 demonstrated infarcts in the mandible. Magnetic resonance images showed bone marrow edema, subperiosteal fluid collections with susceptibility effects suggesting associated hemorrhage, and heterogeneous enhancement. Acute craniofacial bone infarcts were found in 7% of SCD patients who underwent MRI and in 15% of SCD patients who presented with pain. The MRI showed characteristic imaging findings including marrow edema, subperiosteal hematoma, and heterogeneous enhancement.
    Journal of computer assisted tomography 01/2013; 37(1):91-7. · 1.38 Impact Factor
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    ABSTRACT: The objective of this study was to correlate changes in computed tomography perfusion (CTP) parameters in the oropharyngeal mucosa following start of radiotherapy (RT) with acute mucositis in head and neck cancer patients. Fifteen patients were prospectively evaluated with serial CTP imaging. Computed tomography perfusion studies were obtained before RT; at weeks 2, 4, and 6 during RT; and 6 weeks after completion of RT. At week 2 during RT, mean transition time increased to 13.9% and 261.8% in patients with and without mucositis, respectively (P = 0.024). At week 6 of RT, patients with grade 3 mucositis had a 325.4% increase in blood flow compared with a 58.3% increase in patients with grade 0-2 mucositis (P = 0.039). Mean transition time decreased by 29.9% and increased by 187.4% in patients with grade 3 and grade 0-2 mucositis, respectively (P = 0.025). Mean transition time and blood flow changes in the oropharyngeal mucosa correlated with the incidence and severity of RT-related mucositis.
    Journal of computer assisted tomography 01/2013; 37(4):499-504. · 1.38 Impact Factor
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    ABSTRACT: Periapical lucencies are often seen incidentally at head and neck imaging studies performed for indications not related to the teeth. These lesions are, however, occasionally manifestations of diseases that have a wide range of effects and may at times represent the source of symptoms that prompted the study. The vast majority of periapical lucencies are the result of apical periodontal or pulpal disease. If found in an advanced state or left untreated, disease related to the tooth may spread to adjacent tissues, including the sinuses, orbits, deep fascial spaces of the neck, and intracranial structures, and result in a significant increase in patient morbidity and mortality. Although the majority of periapical lucencies seen on radiographs and computed tomographic images occur secondary to apical periodontal or pulpal disease, not all lucencies near the tooth root are due to infection. Lucency near the tooth root may be seen in the setting of other diseases of odontogenic and non-odontogenic origin, including neoplasms. Although imaging findings for these lesions can include periapical lucent components, awareness of the varied secondary imaging features can aid the radiologist in developing an accurate differential diagnosis. Familiarity with the imaging features and differential diagnoses of diseases or conditions that cause lucency around the tooth root results in appropriate referral and prompt diagnosis, management, and treatment, and can prevent unnecessary additional imaging or intervention. In addition, early recognition and appropriate treatment of infectious processes will result in improved clinical outcomes and a decrease in morbidity and mortality.
    Radiographics 01/2013; 33(1):E15-32. · 2.73 Impact Factor
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    ABSTRACT: Objectives The purpose of this prospective study was to characterize the MR relaxometric features of the major salivary glands in patients with sickle cell disease (SCD). Methods 15 patients with SCD (aged 19.8-43.6 years) and 12 controls were imaged with the mixed turbo-spin echo pulse sequence. The major salivary glands were manually segmented and T(1), T(2) and secular T(2) relaxometry histograms were modelled with Gaussian functions. Results Shortened T(1) relaxation times were seen solely in the submandibular glands of patients with SCD (747.5 ± 54.8 ms vs 807.1 ± 38.3 ms, p < 0.001). Slight T(2) and secular T(2) shortening were seen in the parotid gland; however, this difference was not significant (p = 0.07). The sublingual gland showed no changes under MR relaxometry. There was no difference in glandular volumes, and no correlation was demonstrated between history of blood transfusion and salivary gland relaxometry. Conclusions Patients with SCD exhibited changes in quantitative MRI T(1) relaxometry histograms of the submandibular glands.
    Dentomaxillofacial Radiology 12/2012; 41(8):630-6. · 1.27 Impact Factor
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    ABSTRACT: PURPOSE To compare the effects of nonionic neutral and negatively charged ionic contrast agents on 1H magnetic resonance spectroscopy (MRS) of breast cancer at 1.5 tesla. METHOD AND MATERIALS Sixty-two patients with suspicious tumors of the breast measuring 2 cm or larger underwent MRS before and after intravenous administration of either negatively charged ionic contrast agent (Gd-DTPA: gadopentate dimeglumine) (31 patients) or nonionic neutral contrast agent (Gd-HP-DO3A: gadoteridol) (31 patients). We collected single-voxel MRS data from a single rectangular volume of interest (VOI) measuring 15 × 15 × 15 mm3 using a point-resolved spectroscopy sequence, quantified the concentration of total choline-containing compounds (tCho) using solution present in the coil housing as an external reference. We placed a VOI on the lesion by reference to fat-suppressed T2-weighted images and diffusion-weighted images for MRS without contrast and copied and pasted the VOI in the same position for MRS using contrast. We calculated the percentages in change (%) of tCho concentration and the line width and amplitude of tCho peaks before and after administration of the 2 kinds of contrast agent. RESULTS Histologically, all lesions were invasive ductal carcinomas. The mean maximum diameter of the lesions with Gd-DTPA was 39.5 ± 14.3 mm, and that of the lesions with Gd-HP-DO3A was 37.4 ± 14.4. tCho concentrations decreased 13 ± 23% (mean ± SD) after Gd-DTPA administration and 8 ± 18% after Gd-HP-DO3A administration, but the differences were not significant (P = 0.17). The mean peak width of tCho increased 11 ± 25% afterGd-DTPA administration and 8 ± 24% after Gd-HP-DO3A administration, but the difference was not significant (P = 0.70). The mean amplitude of tCho decreased 18 ± 26% after Gd-DTPA administration and 10 ± 27% after Gd-HP-DO3A administration, but the difference was not significant (P = 0.12). CONCLUSION On 1.5-T breast MRS, nonionic neutral and negatively charged ionic contrast materials may decrease tCho concentrations and amplitude and increase the width of choline peaks, but we found no significant difference in such changes between the 2 types of contrast media. CLINICAL RELEVANCE/APPLICATION When precontrast MR imaging cannot show a breast lesion, MRS should be performed after administration of contrast medium. Choice of medium has little effect on choline peak at 1.5 T.
    5 Tesla: Is There Significant Difference Between Nonionic Neutral and Negatively Charged Ionic Contrast Agents?. Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: INTRODUCTION: The left common carotid artery (LCCA) is usually a second branch of the aortic arch that arises between the brachiocephalic trunk (BCT) and left subclavian artery; relatively frequently, it also arises from or shares a common origin with the BCT. In patients with LCCA of anomalous origin, transfemoral catheterization into the LCCA is sometimes difficult, and transbrachial or transradial approach may be recommended. We evaluated the prevalence of these variations on computed tomography (CT) angiography. METHODS: We retrospectively reviewed CT angiographic images of 2,357 patients obtained using either of two 64-slice multidetector CT scanners. All patients were Japanese and underwent scanning from the aortic arch to the intracranial region; most had or were suspected of having cerebrovascular diseases. RESULTS: We evaluated CT angiographic images of 2,352 patients after excluding four patients with LCCA occluded at its origin. The LCCA arose from the BCT in 141 patients (6.0 %) and had a common origin with the BCT in 130 patients (5.5 %). We found 11 aberrant right subclavian artery (0.47 %), and four of the 11 patients (36 %) had LCCA of common origin with the right common carotid artery, forming a bicarotid trunk (prevalence: 0.17 %). CONCLUSIONS: The total prevalence of variations of LCCA origin diagnosed by CT angiography was 11.7 %.
    Anatomia Clinica 11/2012; 35(4). · 1.33 Impact Factor

Publication Stats

158 Citations
94.05 Total Impact Points


  • 2011–2013
    • Boston University
      • Department of Biomedical Engineering
      Boston, Massachusetts, United States
  • 2009–2013
    • Beverly Hospital, Boston MA
      Beverly, Massachusetts, United States
  • 2012
    • University of Massachusetts Boston
      Boston, Massachusetts, United States
    • University of Massachusetts Medical School
      Worcester, Massachusetts, United States
  • 2011–2012
    • Saitama Medical University
      • Center for Maternal, Fetal and Neonatal Medicine
      Saitama, Saitama, Japan
  • 2010–2012
    • Boston Medical Center
      Boston, Massachusetts, United States