Time‐resolved three‐dimensional technique for dynamic magnetic resonance dacryocystography

Nonspecific aortoarteritis (NSAA) is a chronic inflammatory vasculitis involving aorta and its branches. We conducted a study prospectively to compare time resolved magnetic resonance angiography (MRA) with diagnostic digital subtraction angiography (DSA) for the vascular assessment in the patients of NSAA. Seventeen patients of NSAA were recruited in the study over the period of 3 years. Contrast enhanced MRA using Time-resolved angiography With Interleaved Stochastic Trajectories (TWIST) sequence and diagnostic DSA were performed in these 17 patients. The majority of the patients were young (median age was 25 years, range 8 to 46 years) and 11 patients were females. Erythrocyte sedimentation rate (ESR) was elevated in 9 patients and C-reactive protein (CRP) was elevated in 6 patients. Most commonly involved vessels in our patients were right renal artery (14 patients), abdominal aorta (12 patients) and left renal artery (11 patients). Left and right subclavian arteres were involved in 10 and 6 patients respectively. The sensitivity and specificity of time-resolved MRA using TWIST sequence is 100% as compared to DSA in the assessment of major vessels such as aorta, arch vessels, celiac artery and superior mesenteric artery. However, the sensitivity and specificity of time resolved MRA in the evaluation of renal arteries and vertebral arteries were 100%, 71.4% and 85.7%, 33.3% respectively. No significant association of MRI contrast enhancement with erythrocyte sedimentation rate (p = 1.00) and C-reactive protein (p = 0.600). Time resolved MRA images obtained using TWIST sequence were as qualitative as DSA images and can noninvasively evaluate the vascular involvement in NSAA patients.

We describe an investigation of the use of the Insight Toolkit (ITK), a widely used open-source image segmentation and registration software, to obtain the motion transform from the MR images for both rigid and deformable PET motion corrections for simultaneous PET/MR scans. A human brain PET/MR FDG study and two human cardiac PET/MR FDG studies were acquired on Siemens' Biograph-mMR. ITK's 3D-Versor registration was used to obtain the rigid motion transform of the brain from the moved and the reference T2 weighted MR images. Registrations based on B-Spline transform and Demons transform were used to obtain the deformable motion fields from the TWIST (Time-resolved angiography With Interleaved Stochastic Trajectories) and CINE MR images. The motion transforms derived from the registrations were then applied to the PET reconstructions. It has been observed that 3D-Versor registration produces accurate rigid motion transform. With regard to deformable motions, Demons transform performs slightly better than B-Spline transform in terms of %RMSE in the registered TWIST MR images. However, the motion field obtained from the TWIST MR images using Demons transform was observed to introduce irregular distortion in the PET image. On the other hand, Demons motion transforms obtained from the CINE images do not introduce any artifact in the PET image, whereas the B-Spline method does not register the CINE MR images very well. The motion corrected PET image has better signal-to-noise ratio than the gated PET image as expected.

Various imaging modalities have been described for the anatomical and functional assessment of the lacrimal drainage system. Computed tomography (CT) and computed tomographic dacryocystography (CT DCG) are the most useful investigations. There are other investigations for the functional integrity of the lacrimal drainage system. This chapter presents an overview of all available modalities with special emphasis on CT DCG. The available modalities described in the literature include computed tomography, computed tomographic dacryocystography, ultrasound, magnetic resonance imaging, magnetic resonance dacryocystography, scintigraphy and digital subtraction dacryocystography [1–5]. CT DCG is a gold standard investigation for all complex obstructions of the lacrimal drainage system. Most of the PANDO cases can be diagnosed by clinical evaluation but imaging does play an important role in diagnosis and improving results in a select group of PANDO patients presenting with a medial canthal mass. Detection of ethmoid mucocele, nasal polyposis and lacrimal sac diverticulum in failed cases emphasize the importance of thorough preoperative imaging.

This chapter describes the diseases of the orbit, lacrimal gland, and the lacrimal drainage system. The embryology and anatomy of these structures is described shortly. All disease processes are discussed subsequently: congenital abnormalities, inflammation and infection, degenerations, and neoplasms. In order to prevent doublures, certain disease processes and diseases are described in detail as orbital diseases which may be subsequently referred to in the paragraphs of the lacrimal gland and drainage system.

Conventional imaging techniques are not sensitive enough to reveal detailed structures of lacrimal drainage system (LDS) and its surrounding tissue (ST). Our study aimed to explore utility of ultrasound biomicroscopy (UBM) in assessment of small masses at the medial canthal region and compare performance of UBM with conventional imaging techniques. We prospectively recruited cases with small mass (long axis < 1cm) at the medial canthal region (upper LDS-located area) from June 2017 to October 2018. UBM ± color Doppler flow imaging (CDFI) and conventional imaging techniques (computed tomography, magnetic resonance imaging, and dacryocystography) were conducted by four independent practitioners. Results were analyzed against gold standards with Cohen's kappa test in three aspects including LDS patency, mass location, and presumptive diagnosis. Corresponding gold standards were syringe and dacryocystography, intraoperative findings, and pathological/empirical diagnosis. Seventy-two cases were recruited, including 20 cases of LDS lesions and 52 cases of ST lesions. Female (odds ratio 7.14) and age ≥ 37 (odds ratio 9.80) were risk factors for LDS lesion, and age range of 15-25 (odds ratio 9.17) was a risk factor for inflammatory ST lesion. In terms of LDS patency, UBM results were reliable for the detection of pre-saccal obstruction (kappa = 0.920), but were not reliable for intra-saccal and post-saccal obstruction (kappa = 0.106). In terms of mass location, the UBM (kappa = 0.766) performed better than conventional techniques (except for dacryocystography) to sort out ST lesions, with sensitivity of 93.8% and specificity of 83.3%. In terms of diagnosis, the UBM (kappa = 0.882) outweighed conventional techniques (except for magnetic resonance imaging) to distinguish cysts from nodules, with sensitivity of 93.8% and specificity of 94.4%. Notably, the UBM + CDFI achieved better performance than the UBM when screen out inflammatory lesions (kappa = 0.926 vs kappa = 0.689) and LDS-adjacent lesions (kappa = 0.815 vs kappa = 0.673), resulting in sensitivity of 91.7% and specificity of 100% for both testing items. If deep lesions (at the lacrimal sac-harbored area) were excluded, UBM reliability to detect inflammatory lesions (kappa = 0.915) and LDS-adjacent lesions (kappa = 0.770) improved, achieving sensitivity of 90.0% and 88.9%, and specificity of 100.0% and 92.7%, respectively. The UBM is a valuable tool to assess superficial masses at the medial canthal region regarding pre-saccal obstruction, mass location, and presumptive diagnosis. This work was registered on Chinese Clinical Trial Registry website with registration number ChiCTR1800018956 .

In the last few years there has been rapid progress in the application of nuclear magnetic resonance clinical imaging as a diagnostic aid (Partain et al, 1983; Steiner, 1983; Worthington, 1983). Records kept by the operators of NMR imaging equipment indicate that about 1800 individuals have now been examined without incident within the United Kingdom. In view of this progress, an advisory group (Appendix) appointed by the National Radiological Protection Board recommends some modifications to the original advice given in 1981 (NRPB, 1981). The principal modifications are that: (1) It is no longer considered necessary to exclude volunteers with a history of epilepsy or cardiac disease. (2) It is not obligatory that a registered medical practitioner trained in resuscitation techniques be present during an exposure. (3) Higher limits are recommended for rates of change of magnetic flux density when the period of change is less than 10 ms. (4) The radiofrequency limit of 15 MHz has been removed. Theoretical considerations indicate that the interaction of an applied magnetic field with the intrinsic magnetic moments of protons and electrons within a molecule could alter its rate of chemical reaction (McLauchlan, 1981). Chemical reactions involving radical pair intermediates are expected to be sensitive to magnetic fields for this reason and a number of enzyme reactions that might be expected to be affected have been identified (A. Cass, personal communication). However, there is no experimental confirmation of these theoretical possibilities at present.

HomeRadiologyVol. 231, No. 3 PreviousNext EditorialsMR Imaging: Its Development and the Recent Nobel PrizeStephen J. RiedererStephen J. RiedererAuthor Affiliations1From the MR Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. Received January 19, 2004; accepted January 21. Address correspondence to the author (e-mail: [email protected]).Stephen J. RiedererPublished Online:Jun 1 2004https://doi.org/10.1148/radiol.2313040114MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References 1 Lauterbur PC. Image formation by induced local interactions: examples employing nuclear magnetic resonance. Nature 1973; 242:190-191. Crossref, Google Scholar2 USA MRI market Mountain View, Calif: Frost and Sullivan Market Research, 2002. Google Scholar3 Mansfield P, Grannell PK. NMR “diffraction” in solids? J Phys C Solid State Phys 1973; 6:L422. Crossref, Google Scholar4 Mansfield P. 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Computerized fluoroscopy in real time for noninvasive visualization of the cardiovascular system: preliminary studies. Radiology 1979; 130:49-57. Link, Google ScholarArticle HistoryPublished in print: June 2004 FiguresReferencesRelatedDetailsCited ByMedicine, Vol. 93, No. 28Skeletal Radiology, Vol. 40, No. 9Medicine - Programa de Formaci?n M?dica Continuada Acreditado, Vol. 9, No. 92Magnetic Resonance Imaging, Vol. 24, No. 4Applied Magnetic Resonance, Vol. 29, No. 1Pacing and Clinical Electrophysiology, Vol. 28, No. 10Magnetic Resonance Imaging, Vol. 22, No. 10Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 231, No. 3 Metrics Altmetric Score PDF download

ObjectivesMany factors influence the outcome of endoscopic dacryocystorhinostomy (DCR). One of the most important prognostic factors is the level of obstruction in the lacrimal drainage system. The main objective of this report is to evaluate both the frequency of obstruction by anatomical region of the lacrimal drainage system on dacryocystography (DCG) and the surgical outcome of endoscopic DCR according to the obstruction level.MethodsA retrospective series of 48 patients (60 eyes) who had undergone endoscopic DCR from January 2005 to November 2007 were enrolled. Preoperative evaluation consisted of a standard examination which included lacrimal irrigation, probing, DCG and osteomeatal unit (OMU) computed tomography. Patients were classified into four groups according to the obstruction level on DCG. Surgical outcome was evaluated postoperatively by subjective improvement of epiphora and patent rhinostomy opening on nasal endoscopic exam.ResultsOf 60 eyes, the levels of obstruction were the common canaliculus in 14 eyes (23.3%), the lacrimal sac in 13 eyes (21.7%), the duct-sac junction in 13 eyes (21.7%) and the nasolacrimal duct (NLD) in 20 eyes (33.3%). The ductsac junction obstruction was treated most successfully (100%), followed by NLD obstruction (90%), common canaliculus obstruction (78.6%) and saccal obstruction (69.2%).ConclusionIn patients with lacrimal drainage system obstruction, preoperative evaluation of obstruction level using DCG may be helpful for predicting the surgical outcome of endoscopic DCR. The saccal obstruction may have a worse prognosis than the other obstruction levels.

Next to medical therapy, blockage of the lacrimal drainage system is the commonest form of treating dry eye. Rather than applying an artificial tear, the latter helps to preserve any remaining natural tear fluid, which by far has the best wetting and nutrient capacity for the ocular surface. A temporary block is usually induced by implants to tamponade on the level of the lacrimal puncta or canaliculi. A Medline search was performed with the keywords 'lacrimal drainage system, punctum, canaliculus, temporary occlusion, plug, dry eye, keratoconjunctivitis sicca' for the years 1986-2006. Plugs are a suitable treatment in patients with moderate or more severe disease. The characteristics of the devices used and procedures as well as the complications described were analyzed. Criteria such as a lack of Schirmer strip wetting, ocular surface staining and the frequency of artificial tears instillation should be assessed prior to making the decision to occlude the lacrimal drainage. Lacrimal plugs made of silicone or a thermodynamic acrylic polymer, such as hydrogel, appear to be safe and effective, although each patient should be followed on a long-term basis to exclude alterations of the lacrimal system such as chronic inflammatory reactions, extrusion or migration, which may all lead to discomfort. High-frequency ultrasound as a non-invasive, simple diagnostic technique can be used to identify the type or position of plug or inflammatory reaction present. Tamponade of the lacrimal drainage system is a simple procedure that is underused. Preserving natural tears by blocking the lacrimal drainage system can successfully maintain the integrity of the ocular surface and corneal transparency and visual acuity. In patients with moderate or severe dry eye, it is capable of improving quality of life and preventing loss of vision.

Introduction: Magnetic Resonance Imaging (MRI) has an excellent soft tissue resolution and can detect and accurately characterise lesions which are not seen on other imaging modalities like mammography or ultrasonography. Dynamic Contrast Enhanced (DCE) MRI is better for characterisation of fibroglandular tissue and breast lesions as it further improves specificity of MRI. Kinetic Curves (KC) derived from DCE MRI according to the wash in and wash out patterns of intravenous contrast are analysed and correlated with morphology of a lesion. Aim: To evaluate the efficacy of DCE MRI in detection and characterisation of breast lesions according to KC analysis and to correlate MRI findings with pathological findings. Materials and Methods: A prospective observational study was conducted at Guru Gobind Singh Medical College and Hospital, Faridkot, Punjab, India. DCE MRI was performed after informed consent in 50 females (Age ranging from 17 years to 80 years). MRI was conducted on Siemens “MAGNETOM Avanto” 1.5 Tesla machine using standard dedicated breast matrix coils. The standard MRI protocol included the T1 and T2 weighted fat-sat sequences along with DCE MRI after intravenous administration of Meglumine-Gadoterate (0.1 mmol/kg body weight) followed by a 20-mL saline flush. Post processing manipulation included standard subtraction, reverse subtraction, Maximum-Intensity Projection (MIP) images and KC analysis. Findings of DCE MRI were graded according to Breast Imaging-Reporting and Data System (BI-RADS) category after morphological and KC analysis and were correlated with pathological findings. Results: MRI is a highly sensitive modality to detect breast lesions especially bilateral and multifocal/multicentric lesions with sensitivity of 98.18%. However, specificity was relatively low (55.56%). The Positive and Negative Predictive Values (PPV, NPV) of MRI in characterisation of breast lesions in present study were 93.10% and 83.33%, respectively. Conclusion: Although MRI is extremely sensitive for detecting breast lesions it has a relatively low specificity. Both morphological characteristics and KC analysis should be used in combination for interpretation as it improves the specificity of MRI.

Dacryostenosis, a chronic ophthalmologic condition characterized by partial or total obstruction of the lacrimal drainage system, has been the subject of in-depth scrutiny in the medical literature. This article aims to comprehensively investigate dacryostenosis from a clinical and surgical perspective, providing a comprehensive analysis of its etiology, clinical manifestations, and available treatment options. Through a critical review of the current literature and presentation of data from a prospective cohort of patients, we explore state-of-the-art diagnostic modalities, such as magnetic resonance dacryocystography and optical coherence tomography, which have revolutionized the evaluation of dacryostenosis. Regarding surgical management, traditional techniques, such as dacryocystorhinostomy, are discussed, together with the latest innovations, such as endoscopic dacryoplasty and intranasal balloon dilatation. A detailed comparison of the advantages and disadvantages of these techniques is presented, along with their success rates and associated complications. Finally, long-term outcomes are examined, including improvement in patients' quality of life, symptom reduction, and durability of surgical interventions. This article provides a comprehensive view of dacryostenosis, highlighting the importance of a multidisciplinary approach to its management and the pivotal role of surgery in restoring tear function and ocular well-being.

It is frequently stated in the literature that there is a common canaliculus (CC) in the lacrimal drainage system in about 90% of individuals; in the remaining 10%, the upper and lower canaliculi enter the lacrimal sac separately. To our knowledge, there is no quantitative study supporting this assumption. To investigate the frequency of the CC and other anatomical types connecting the upper and lower canaliculi to the lacrimal sac. We presumed that there might be 3 different types of anatomical connection between the lacrimal sac and the canaliculi. Digital subtraction macrodacryocystograms obtained from 281 patients with obstructive epiphora were reviewed, and those of 247 patients were included in the study. These patients were grouped according to the anatomical types. Dacryocystographies were performed on 153 patients unilaterally and 94 bilaterally. We observed a CC in 321 (94.1%) of 341 lacrimal drainage systems. In 13 lacrimal drainage systems (3.8%), the CC was absent, but the upper and lower canaliculi joined at the wall of the lacrimal sac. In only 7 lacrimal drainage systems (2.0%) did the upper and lower canaliculi enter the sac separately. In 2 patients with bilateral dacryocystograms, a CC was seen on one side but not on the other side. The frequency of separate drainage of the upper and lower canaliculi into the lacrimal sac is only 2.0%. The CC might not be present bilaterally in all individuals.

Treatment of nasolacrimal duct obstruction in adults with polyurethane stent

To determine the accuracy of magnetic resonance (MR) imaging in comparison to cerebral angiography after radiosurgery for an arteriovenous malformation (AVM), the authors reviewed the records of patients who underwent radiosurgery at the University of Pittsburgh Medical Center before 1992. All patients in the analysis had AVMs in which the flow-void signal was visible on preradiosurgical MR imaging. One hundred sixty-four postradiosurgical angiograms were obtained in 140 patients at a median of 2 months after postradiosurgical MR imaging (median 24 months after radiosurgery). Magnetic resonance imaging correctly predicted patency in 64 of 80 patients in whom patent AVMs were seen on follow-up angiography (sensitivity 80%) and angiographic obliteration in 84 of 84 patients (specificity 100%). Overall, 84 of 100 AVMs in which evidence of obliteration was seen on MR images displayed angiographic obliteration (negative predictive value, 84%). Ten of the 16 patients with false-negative MR images underwent follow-up angiography: in seven the lesions progressed to complete angiographic obliteration without further treatment. Exclusion of these seven patients from the false-negative MR imaging group increases the predictive value of a negative postradiosurgical MR image from 84% to 91%. No AVM hemorrhage was observed in clinical follow up of 135 patients after evidence of obliteration on MR imaging (median follow-up interval 35 months; range 2-96 months; total follow up 382 patient-years). Magnetic resonance imaging proved to be an accurate, noninvasive method for evaluating the patency of AVMs that were identifiable on MR imaging after stereotactic radiosurgery. This imaging modality is less expensive, more acceptable to patients, and does not have the potential for neurological complications that may be associated with cerebral angiography. The risk associated with follow-up cerebral angiography may no longer justify its role in the assessment of radiosurgical results in the treatment of AVMs.

To report long-term outcomes after surgery for primary benign papillomas of the lacrimal drainage system. Retrospective review of patients with primary lacrimal drainage system papillomas, first seen between 1984 and 2021, but excluding lesions with sino-nasal origin or malignant histology. Patients were categorized by tumor histology (squamous, transitional, and mixed cell) and growth pattern (exophytic, endophytic, or mixed). Thirty patients (18 female; 60%) presented at a mean age of 46.1 years (12-79 years). Over an average follow-up of 10.4 years, 30% of patients experienced recurrence, with rates differing slightly by growth pattern: 25% for exophytic tumors and 40% for endophytic and mixed-pattern tumors ( p = 0.431). The overall 5-year recurrence-free survival was 67% (± 9% standard error), this being slightly higher for exophytic lesions (75% ± 10%) as compared to 48% (± 19%) for tumors with an endophytic component ( p = 0.370). No cases of malignant transformation were observed, and the tumor type at recurrence matched the initial diagnosis. Primary benign papillomas of the lacrimal drainage system have a long-term recurrence rate of about one-third, with a higher frequency in those exhibiting an endophytic growth pattern. The study highlights the importance of prolonged surveillance for recurrence, especially for endophytic and mixed growth pattern tumors, and for the potential to undergo malignant transformation. The results support the effectiveness of endoscopic surgical excision or laser thermos-ablation in managing recurrent lacrimal drainage system papillomas after dacryocystorhinostomy.