Alternative Imaging Technique Research Articles

Coronary Anatomy in the Newborn: What Do We Need to Know and When?

Coronary Anatomy in the Newborn: What Do We Need to Know and When?

Predicting stone composition before treatment - can it really drive clinical decisions?

IntroductionDetermination of stone composition is considered to be crucial for the choice of an optimal treatment algorithm. It is especially important for uric acid stones, which can be dissolved by oral chemolysis and for renal stones smaller than 2 cm, which can be treated with extracorporeal shockwave lithotripsy (ESWL).Material and methodsThis short review identifies the latest papers on radiological assessment of stone composition and presents a comprehensive evaluation of current scientific findings.ResultsStone chemical composition is difficult to predict using standard CT imaging, however, attenuation index measured in Hounsfield units (HU) is related to ESWL outcome. Stone density >1000 HU can be considered predictive for ESWL failure. It seems that stone composition is meaningless in determining the outcome of ureterolithotripsy and percutaneous surgery. Alternative imaging techniques such as Dual–Energy CT or analysis of shape, density and homogeneity of stones on plain X–rays are used as promising methods of predicting stone composition and ESWL outcome.ConclusionsNew imaging techniques facilitate the identification of uric acid stones and ESWL–resistant stones. Therefore, they may help in selecting the best therapeutic option.

Infarct size by SS-SSFP vs. IR-GRE: influence of imaging time after contrast administration and infarct age, and implications for clinical trials

Background Myocardial late gadolinium enhancement (LGE) imaging is conventionally acquired using a gradient-echo inversion recovery (IR-GRE) sequence 15-20 min after contrast administration. However, this method can be limited by poor breath holding or arrhythmias. Freebreathing single shot steady state free precession (SSSSFP) sequence is an alternative LGE imaging technique which can overcome some of the IR-GRE limitations but at the expense of lower resolution. The ideal imaging timing for LGE SS-SSFP, and whether it can be used interchangeably with IR-GRE has not yet been established. The aim of our study was to investigate acute and chronic infarct size: 1) Comparing LGE by SS-SSFP vs. IR-GRE at 15 min. 2) Comparing LGE SSSSFP imaging at 5 vs. 10 vs. 15 min after contrast administration vs. IR-GRE at 15 min.

Clinical investigation of flat panel CT following middle ear reconstruction: a study of 107 patients

After middle ear reconstruction using partial or total ossicular replacement prostheses (PORP/TORP), an air-bone gap (ABG) may persist because of prosthesis displacement or malposition. So far, CT of the temporal bone has played the main role in the diagnosis of reasons for postoperative insufficient ABG improvement. Recent experimental and clinical studies have evaluated flat panel CT (fpCT) as an alternative imaging technique that provides images with high isovolumetric resolution, fewer metal-induced artefacts and lower irradiation doses. One hundred and seven consecutive patients with chronic otitis media with or without cholesteatoma underwent reconstruction by PORP (n = 52) or TORP (n = 55). All subjects underwent preoperative and postoperative audiometric testing and postoperative fpCT. Statistical evaluation of all 107 patients as well as the sole sub-assembly groups (PORP or TORP) showed a highly significant correlation between hearing improvement and fpCT-determined prosthesis position. FpCT enables detailed postoperative information on patients with middle ear reconstruction. FpCT is a new imaging technique that provides immediate feedback on surgical results after reconstructive middle ear surgery. Specific parameters evaluated by fpCT may serve as a predictive tool for estimated postoperative hearing improvement. Therefore this imaging technique is suitable for postoperative quality control in reconstructive middle ear surgery. • Flat panel CT offers advantages with regard to artefacts and radiation dose. • FpCT provides higher isovolumetric resolution of temporal bone and middle ear implants. • FpCT allows prediction of the postoperative hearing outcome in patients. • FpCT is an important tool for immediate postoperative quality control. • FpCT improves postoperative management of patients with complications following ossicular replacement.

Deep seismic image enhancement with the common reflection surface (CRS) stack method: evidence from the Aravalli–Delhi fold belt of northwestern India

Imaging of deep crustal features from narrow-angle deep seismic reflection data, especially from fold belt region, has been a challenging task. The common reflection surface (CRS) stack is an alternative seismic imaging technique for multicoverage reflection data. It is an automatic stacking process, which does not require explicit knowledge of stacking velocity. This CRS stack is especially useful when the data quality is poor and foldage is low. In this paper, we demonstrate an application of the CRS stack to a deep seismic reflection data set acquired across the Aravalli–Delhi fold belt of the northwestern India, which provides a seismic stack section with much improved signal-to-noise ratio. Comparing the conventional common mid-point (CMP) Stack with the CRS stack, we find that the Moho and other crustal reflections have been resolved clearly and the continuity of the reflectors has also been enhanced with the CRS stack method. The major findings from our CRS processing include clear image of the Moho discontinuity below the Marwar Basin and Sandmata Complex, and prominent upper and mid-crustal reflections. Our study for the first time images an extension of crustal-scale Jahazpur thrust below the Sandmata Complex, which becomes listric at the Moho. Some of the crustal features derived in this study were not identified in the earlier investigations using the CMP stack. Our study clearly demonstrates that the CRS stacking method is more appropriate for imaging the crustal and subcrustal structures of the thrust fold belt region than the conventional CMP method, where limited velocity information is available. Crustal thickness across the Proterozoic orogenic Aravalli–Delhi fold belt varies between 38 and 50 km. Global correlation of the seismic results suggests no relation between crustal thickness and age of the crustal block, but it depends on the thermorheological and tectonic history of the region. Palaeosignatures of the Proterozoic subduction and collision processes are still preserved in major portion of the crust in this study area as well as in several parts of the world.

Detection, characterization and endovascular therapy planning of intracranial aneurysms with 16-channel multidetector row CT angiography

AimTo study the role of multidetector row CT angiography (MDCTA) in detection, characterization and endovascular therapy planning of intracranial aneurysms in comparison with digital subtraction angiography (DSA). Material and methodsBetween April 2011 and March 2012, prospective study of 43 patients with suspected cerebral aneurysms (27 females and 16 males) was done, their ages ranged from 40 to 74years. Patients were referred to the Radiodiagnosis Department, from neurology and neuro-surgery departments for suspected cerebrovascular lesions. Aneurysm detection with multidetector CT angiography and DSA was analyzed. ResultsThe MDCT angiograms were interpreted for the presence, location, size, ratios of the aneurysm (dome to neck ratio (D/N), aspect ratio), neck width, lobularity of the aneurysms and relationship of the aneurysm with the adjacent arterial branches, by using volume-rendering techniques.MDCT and DSA were done for all patients. Twenty-three patients had a single aneurysm, 4 had 2 aneurysms, 2 had 5 aneurysms and no aneurysms were detected in 14 patients presented with subarachnoid hemorrhage on unenhanced CT, the most common shape was saccular aneurysm (90%) and the most common size was medium size (43.9%). We determined the neck of 28 aneurysm (68%) and the remaining 13 could not be determined (32%).Among 41 cerebral aneurysms, 26 aneurysms were detected in anterior circulation (63.4%) and 15 in posterior circulation (36.5%). The middle cerebral artery (29.2%) was the most common site.In 55% of studied cases presented with aneurysmal rupture SAH was the commonest type of hemorrhage. According to Hunt and Hiss classification grades 2 and 3 were the most prevalent (17 patients and 6 patients respectively) followed by grade 4 (4 patients) and lastly grades 0 and 1 (one patient for each). ConclusionSixteen channel Multidetector CT angiography offers high diagnostic accuracy nearly equivalent to that of DSA in the detection of intracranial aneurysms. However, 16 channel- MDCTA still has limited sensitivity in detecting aneurysms of 3mm or less, despite its technical advances. MDCT can be used as a reliable alternative imaging technique to DSA in selected cases.

Evaluation of the relationship between extremity soft tissue sarcomas and adjacent major vessels using contrast-enhanced multidetector CT and three-dimensional volume-rendered CT angiography: a preliminary study

Accurate description of the relationship between extremity soft tissue sarcoma and the adjacent major vessels is crucial for successful surgery. In addition to magnetic resonance imaging (MRI) or in patients who cannot undergo MRI, two-dimensional (2D) postcontrast computed tomography (CT) images and three-dimensional (3D) volume-rendered CT angiography may be valuable alternative imaging techniques for preoperative evaluation of extremity sarcomas. To preoperatively assess extremity sarcomas using multidetector CT (MDCT), with emphasis on postcontrast MDCT images and 3D volume-rendered MDCT angiography in evaluating the relationship between tumors and adjacent major vessels. MDCT examinations were performed on 13 patients with non-metastatic extremity sarcomas. Conventional CT images and 3D volume-rendered CT angiography were evaluated, with focus on the relationship between tumors and adjacent major vessels. Kappa consistency statistics were performed with surgery serving as the reference standard. The relationship between sarcomas and adjacent vessels was described as one of three patterns: proximity, adhesion, and encasement. Proximity was seen in five cases on postcontrast CT images or in eight cases on volume-rendered images. Adhesion was seen in three cases on both postcontrast CT images and volume-rendered images. Encasement was seen in five cases on postcontrast CT images or in two cases on volume-rendered images. Compared to surgical results, postcontrast CT images had 100% sensitivity, 83.3% specificity, 87.5% positive predictive value, 100% negative predictive value, and 92.3% accuracy in the detection of vascular invasion (κ = 0.843, P = 0.002). 3D volume-rendered CT angiography had 71.4% sensitivity, 100% specificity, 100% positive predictive value, 75% negative predictive value, and 84.6% accuracy in the detection of vascular invasion (κ = 0.698, P = 0.008). On volume-rendered images, all cases with adhesion or encasement had arterial stenosis and all tumors' feeding arteries were clearly depicted. 2D postcontrast CT images are superior to 3D volume-rendered CT angiography in evaluating the relationship between extremity sarcomas and adjacent major vessels. 3D volume-rendered CT angiography is good at assessing the tumor's blood supply, the longitudinal extent of vascular involvement, and the vascular narrowing due to the tumor.

Imaging of mandible invasion by oral squamous cell carcinoma using computed tomography, cone-beam computed tomography and bone scintigraphy with SPECT

The objective of this paper is to evaluate the predictability of preoperative tumour bone invasion of the mandible by squamous cell carcinoma of the oral cavity using CT, cone-beam CT and bone scintigraphy with SPECT. Eighty-four patients who had received CT, SPECT or cone-beam computed tomography (CBCT), as well as a further 48 patients who undergone all these investigations for preoperative evaluation of bone invasion were included in the study. A case-control analysis and the receiver operating characteristics were performed. Histological results of bone specimens served as the gold standard for assessment of bone invasion. CBCT and SPECT showed a comparable sensitivity for bone invasion (93 % [CI 0.816-0.972] and 96 % [CI 0.867-0.990], respectively) which was significantly higher than that of CT (63 % [CI 0.488-0.752]). Further, CBCT obtained higher specificity than SPECT (62 % [CI 0.478-0.743] and 48 % [CI 0.342-0.614], respectively), whereas CT showed the best specificity among the investigation methods (81 % [CI 0.677-0.896]). CT scan provides by its high specificity and positive predictive value a precise imaging technique for clinical routine. However, CBCT shows a much higher sensitivity for cortical bone invasion and a better negative predictive value. With a significantly lower exposure dose it can rule out this invasion effectively and prevent overtreatment. Considering the high-resolution images delivered by CBCT along with minimized artefacts in the mandible it provides an alternative imaging technique, which could be combined and accomplished with another soft-tissue imaging modality like MRI to obtain optimal hard and soft-tissue visualisation in patients with squamous cell carcinoma of the oral cavity.

Development of a dynamic quality assurance testing protocol for multisite clinical trial DCE-CT accreditation

Credentialing can have an impact on whether or not a clinical trial produces useful quality data that is comparable between various institutions and scanners. With the recent increase of dynamic contrast enhanced-computed tomography (DCE-CT) usage as a companion biomarker in clinical trials, effective quality assurance, and control methods are required to ensure there is minimal deviation in the results between different scanners and protocols at various institutions. This paper attempts to address this problem by utilizing a dynamic flow imaging phantom to develop and evaluate a DCE-CT quality assurance (QA) protocol. A previously designed flow phantom, capable of producing predictable and reproducible time concentration curves from contrast injection was fully validated and then utilized to design a DCE-CT QA protocol. The QA protocol involved a set of quantitative metrics including injected and total mass error, as well as goodness of fit comparison to the known truth concentration curves. An additional region of interest (ROI) sensitivity analysis was also developed to provide additional details on intrascanner variability and determine appropriate ROI sizes for quantitative analysis. Both the QA protocol and ROI sensitivity analysis were utilized to test variations in DCE-CT results using different imaging parameters (tube voltage and current) as well as alternate reconstruction methods and imaging techniques. The developed QA protocol and ROI sensitivity analysis was then applied at three institutions that were part of clinical trial involving DCE-CT and results were compared. The inherent specificity of robustness of the phantom was determined through calculation of the total intraday variability and determined to be less than 2.2±1.1% (total calculated output contrast mass error) with a goodness of fit (R2) of greater than 0.99±0.0035 (n=10). The DCE-CT QA protocol was capable of detecting significant deviations from the expected phantom result when scanning at low mAs and low kVp in terms of quantitative metrics (Injected Mass Error 15.4%), goodness of fit (R2) of 0.91, and ROI sensitivity (increase in minimum input function ROI radius by 146±86%). These tests also confirmed that the ASIR reconstruction process was beneficial in reducing noise without substantially increasing partial volume effects and that vendor specific modes (e.g., axial shuttle) did not significantly affect the phantom results. The phantom and QA protocol were finally able to quickly (<90 min) and successfully validate the DCE-CT imaging protocol utilized at the three separate institutions of a multicenter clinical trial; thereby enhancing the confidence in the patient data collected. A DCE QA protocol was developed that, in combination with a dynamic multimodality flow phantom, allows the intrascanner variability to be separated from other sources of variability such as the impact of injection protocol and ROI selection. This provides a valuable resource that can be utilized at various clinical trial institutions to test conformance with imaging protocols and accuracy requirements as well as ensure that the scanners are performing as expected for dynamic scans.

Differentiation of Breast Cancer from Fibroadenoma with Dual-Echo Dynamic Contrast-Enhanced MRI

Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) of the breast is a routinely used imaging method which is highly sensitive for detecting breast malignancy. Specificity, though, remains suboptimal. Dynamic susceptibility contrast magnetic resonance imaging (DSC MRI), an alternative dynamic contrast imaging technique, evaluates perfusion-related parameters unique from DCE MRI. Previous work has shown that the combination of DSC MRI with DCE MRI can improve diagnostic specificity, though an additional administration of intravenous contrast is required. Dual-echo MRI can measure both T1W DCE MRI and T2*W DSC MRI parameters with a single contrast bolus, but has not been previously implemented in breast imaging. We have developed a dual-echo gradient-echo sequence to perform such simultaneous measurements in the breast, and use it to calculate the semi-quantitative T1W and T2*W related parameters such as peak enhancement ratio, time of maximal enhancement, regional blood flow, and regional blood volume in 20 malignant lesions and 10 benign fibroadenomas in 38 patients. Imaging parameters were compared to surgical or biopsy obtained tissue samples. Receiver operating characteristic (ROC) curves and area under the ROC curves were calculated for each parameter and combination of parameters. The time of maximal enhancement derived from DCE MRI had a 90% sensitivity and 69% specificity for predicting malignancy. When combined with DSC MRI derived regional blood flow and volume parameters, sensitivity remained unchanged at 90% but specificity increased to 80%. In conclusion, we show that dual-echo MRI with a single administration of contrast agent can simultaneously measure both T1W and T2*W related perfusion and kinetic parameters in the breast and the combination of DCE MRI and DSC MRI parameters improves the diagnostic performance of breast MRI to differentiate breast cancer from benign fibroadenomas.

Role of volumetric three-dimensional computed tomography in guiding the treatment of a dentigerous cyst associated with a mesiodens, approaching the nasal cavity

AbstractThis is a case report highlighting the role of volumetric three-dimensional computed tomography (3D-CT) in the treatment of a dentigerous cyst (DC) associated with a mesiodens approaching the nasal cavity. The incidence and histopathogenesis of DC associated with mesiodens have been discussed. The advantages of volumetric multi-slice light speed 3D-CT imaging over alternative CT imaging techniques have also been discussed.

Crustal complexity in the Lachlan Orogen revealed from teleseismic receiver functions

There is an ongoing debate about the tectonic evolution of southeast Australia, particularly about the causes and nature of its accretion to a much older Precambrian core to the west. Seismic imaging of the crust can provide useful clues to address this issue. Seismic tomography imaging is a powerful tool often employed to map elastic properties of the Earth's lithosphere, but in most cases does not constrain well the depth of discontinuities such as the Mohorovičić (Moho). In this study, an alternative imaging technique known as receiver function (RF) has been employed for seismic stations near Canberra in the Lachlan Orogen to investigate: (i) the shear-wave-velocity profile in the crust and uppermost mantle, (ii) variations in the Moho depth beneath the Lachlan Orogen, and (iii) the nature of the transition between the crust and mantle. A number of styles of RF analyses were conducted: H-K stacking to obtain the best compressional–shear velocity (V P /V S) ratio and crustal thickness; nonlinear inversion for the shear-wave-velocity structure and inversion of the observed variations in RFs with back-azimuth to investigate potential dipping of the crustal layers and anisotropy. The thick crust (up to 48 km) and the mostly intermediate nature of the crust−mantle transition in the Lachlan Orogen could be due to the presence of underplating at the base of the crust, and possibly to the existing thick piles of Ordovician mafic rocks present in the mid and lower crust. Results from numerical modelling of RFs at three seismic stations (CAN, CNB and YNG) suggest that the observed variations with back-azimuth could be related to a complex structure beneath these stations with the likelihood of both a dipping Moho and crustal anisotropy. Our analysis reveals crustal thickening to the west beneath CAN station which could be due to slab convergence. The crustal thickening may also be related to the broad Macquarie volcanic arc, which is rooted to the Moho. The crustal anisotropy may arise from a strong N–S structural trend in the eastern Lachlan Orogen and to the preferred crystallographic orientation of seismically anisotropic minerals in the lower and middle crust related to the paleo-Pacific plate convergence.

Contemporary evaluation of urography in diagnosis in patients with urothelial cell carcinoma.

312 Background: Upper urinary tract tumors (UUTT) can occur synchronous or metachronous (0.7 – 6%) with bladder tumors. The optimal imaging technique of the upper urinary tract is unclear. Studies on the accuracy of retrograde pyelography (RUP) and comparative studies on detection level are sparse. In this study we evaluated the effectiveness of a first RUP in patients with a first manifestation of urothelial cell carcinoma (UCC) in the urinary tract. Methods: In this retrospective study we evaluated all consecutive patients with pathologic proven UCC who underwent their first RUP between March 1998 and April 2008 in the University Medical Center Groningen, Netherlands. Data regarding patient and tumor characteristics, results from RUPs, use of alternative imaging techniques, treatment and outcome were collected from the electronically patient’s records. Follow up was calculated from the first RUP to the last registrated visit. Descriptive statistics have been used to evaluate the performance of the RUP. Results: A total of 156 patients underwent a first RUP because of a first manifestation of UCC of the bladder or upper urinary tract. A mean follow up of 5.09 years was achieved (range 0-13 years). On 17 RUPs (11%) abnormalities were detected. In 16 patients a malignancy was diagnosed. Except one renal cell carcinoma all tumors were UCC of the renal pelvis, ureters or both. Muscle invasive tumors were diagnosed in 7 of these 17 patients. In 30 patients (19%) no conclusive results were obtained because of failure of the RUP due to technical difficulties. In 19 of 30 patients alternative imaging was performed, with intravenous pyelography in 11 patients, computer tomography urography in 7 patients and with both in 1 patient. No UUTTs were diagnosed in this group. In 109 (70%) patients whit a negative RUP three patients developed a tumor after 8, 52, and 65 months. The latter two we consider as newly developed lesions. Conclusions: RUP in patients with a first manifestation of UCC is a very sensitive and accurate diagnostic tool in detecting UUTT.

On-chip biomedical imaging.

Lab-on-a-chip systems have been rapidly emerging to pave the way toward ultra-compact, efficient, mass producible and cost-effective biomedical research and diagnostic tools. Although such microfluidic and microelectromechanical systems have achieved high levels of integration, and are capable of performing various important tasks on the same chip, such as cell culturing, sorting and staining, they still rely on conventional microscopes for their imaging needs. Recently, several alternative on-chip optical imaging techniques have been introduced, which have the potential to substitute conventional microscopes for various lab-on-a-chip applications. Here we present a critical review of these recently emerging on-chip biomedical imaging modalities, including contact shadow imaging, lens-free holographic microscopy, fluorescent on-chip microscopy and lens-free optical tomography.

Current Status and New Developments in Breast Cancer Diagnosis and Detection

Despite extensive research into new ways of imaging the breast x-ray mammography and breast ultrasound, supplemented where necessary by magnetic resonance imaging, remain the techniques used for the vast majority of breast imaging for screening and the assessment of symptomatic breast problems. Recent advances in these technologies mean that these three techniques are highly effective for both detecting disease and for confirming normality. X-ray based imaging of the breast has been around now for 100 years but it is only in the last 10 years or so that digital technology developments have allowed for major advances in the efficacy of this technique. Digital breast tomosynthesis is currently the most promising technology as it has the potential to both improve detection of breast cancer and greatly reduce the numbers of false positive events. Technological advances in grey scale high frequency ultrasound imaging mean that it is now universally used in both symptomatic diagnosis and breast screening. Newer ultrasound techniques such as 3D imaging, Doppler analyses and elastography add some additional value but so far none of these has achieved their hoped for additional potential. Magnetic resonance imaging is currently the most sensitive imaging technique for the detection and characterisation of breast disease, but its cost remains a barrier to its more widespread use. Nuclear medicine techniques have a role is special circumstances but are yet to show that they should be used in routine practice. There are a large number of potential alternative new imaging techniques for the breast, but, as yet, none of these have shown any significant benefits over the current techniques. Dedicated breast computed tomography has perhaps the best promise but clinically effective breast imaging at present remains in the application and refinement of recent developments in digital mammography, ultrasound and magnetic resonance imaging.

Predictive Value of Current Imaging Modalities for the Detection of Urolithiasis During Pregnancy: a Multicenter, Longitudinal Study

We determined the optimal imaging study by which to diagnose and treat pregnant patients with suspected urolithiasis. A retrospective, multicenter study was performed to determine the comparative accuracy of imaging modalities used before the surgical management of suspected urolithiasis in pregnant patients. Patients with a clinical suspicion of urolithiasis were evaluated with directed imaging including renal ultrasound alone, renal ultrasound and low dose computerized tomography, or renal ultrasound and magnetic resonance urography. When indicated, patients underwent therapeutic ureteroscopy. The rate of negative ureteroscopy was determined and the positive predictive values of the imaging modalities were calculated. A total of 51 pregnant patients underwent ureteroscopy. The mean age of the cohort was 27 years. Mean gestational age was 24.4 weeks. Of the women 24 (47%) underwent renal ultrasound and low dose computerized tomography, 22 (43%) underwent ultrasound alone, and 5 (10%) underwent renal ultrasound and magnetic resonance urography. Negative ureteroscopy occurred in 7 of the 51 patients (14%). The rate of negative ureteroscopy among patients who underwent renal ultrasound alone, renal ultrasound and low dose computerized tomography, and renal ultrasound and magnetic resonance urography was 23%, 4.2% and 20%, respectively. The positive predictive value of computerized tomography, magnetic resonance and ultrasound was 95.8%, 80% and 77%, respectively. The rate of negative ureteroscopy was 14% among pregnant women undergoing intervention in our series. Of the group treated surgically after imaging with ultrasound alone, 23% had no ureteral stone, resulting in the lowest positive predictive value of the modalities used. Alternative imaging techniques, particularly low dose computerized tomography, offer improved diagnostic information that can optimize management and obviate unnecessary intervention.

Does MR Sialography Have A Greater Diagnostic Accuracy Than Conventional X-Ray And Digital Subtraction Sialography In Detecting Salivary Glands Disease? A Literature Review

Aim: The main aim was to determine the diagnostic accuracy of MR Sialography as compared to conventional x-ray and digital sialography in detecting salivary gland diseases on the basis of research evidences available in the literature. Description: It is noticed that almost all people develop illness of salivary glands at some stage of their lives. The major effects on salivary glands become evident as stones; infection tumors which may also involve related organs. Imaging methods like Ultrasound, Computed Tomography (CT) and Digital subtraction sialography (DSS) are used for assessment of parotid, sub-mandibular and sub-lingual glands in addition to conventional x-ray sialography which is marked as a gold standard for salivary glands assessment. Due to the non-invasive nature and level of comfort, MR Sialography is now being considered as an advanced technique for the detection of stones and tumor spread in the soft tissues with no risk of radiation exposure. Methods and Results: Different databases which include Science direct, CINAHL, Ebesco Host, PubMed, Swetswise, Wiley Interscience, sage pub, and The Cochrane library were explored to get published literature. Total 10 studies were included and critically appraised under critical appraisal skills programme (CASP) tool. Conclusion: The review proposed that though the use of MRS as the only diagnostic examination is useful but X-ray sialography remains the standard investigation tool due to its higher spatial resolution. MRS can be utilized as an alternative imaging technique by using special MR sequences such as 3D CISS and RARE where x-ray sialography cannot be performed. DOI: http://dx.doi.org/10.3126/njr.v1i1.6329 Nepalese Journal of Radiology Vol.1(1): 70-77

Medical radiation exposure in children with bleeding disorders: an institutional experience

Patients with bleeding disorders may be exposed to ionizing radiation during medical care. We hypothesized that children with severe haemophilia may have higher radiation exposure than those with mild bleeding disorders (MBDs). To compare medical radiation exposure rates between children with severe haemophilia and MBDs. Charts of 35 pediatric patients with severe haemophilia were randomly selected from a database of active male patients followed in our bleeding disorders clinic from 2000 to 2010. Case patients were age and sex matched with two control patients with MBDs [Type 1 von Willebrand disease (VWD) or mild platelet function defect (PFD)]. By retrospective review, data on radiation exposure in millisieverts (mSv) was collected from radiological studies performed within Emory/CHOA. The rates of exposure between cohorts were compared using the Mann-Whitney Test. Case patients had a mean of 11.3 (median 8, IQR = 29) radiographic studies compared with 1.8 (median 1, IQR = 11) for controls (P < 0.001). The mean effective dose of radiation per patient per year of study was two mSv for case patients (median 0.4, IQR = 3) and 0.4 mSv for control patients (median 0.01, IQR = 0.3) (P < 0.001). Overall, 1.4% of controls and 31.4% of cases accumulated high to very high levels of exposure ( > 20 mSv). Case patients with severe hemophilia accumulated significantly more medical radiation exposure than controls. While the use of ionizing radiation is often necessary for management of these patients, avoidance of unnecessary exposure along with exploration of alternative imaging techniques and low dose protocols should be considered whenever possible.

Patterns of diagnostic imaging and cumulative radiation exposure among long-term young adult cancer survivors.

6027 Background: Young adults surviving a diagnosis of malignancy have a considerable life expectancy, however, little is known about radiation exposure from diagnostic imaging in these patients. This study aims to describe patterns of imaging and radiation exposure in young adult cancer survivors (YAS) and cancer-free controls in Ontario, Canada. Methods: We conducted a population-based retrospective study. Young adults aged 20-44 diagnosed with an invasive malignancy between 1992 and 1999 who lived at least 5 years without recurrent disease were identified in the Ontario Cancer Registry. YAS were matched 1:5 to randomly selected cancer-free controls on calendar year of birth, sex, and geographic location. Radiological procedures were identified through Ontario Health Insurance Plan administrative data. The rate at which individuals underwent diagnostic procedures after surviving 5-years was compared between survivors and controls using Poisson regression. Cumulative radiation exposure due to computed tomography (CT) and standard x-ray were calculated. Results: 20,911 YAS and 104,524 controls had a median of 13.5 years observation time after cancer diagnosis/referent date. The rate of CT scanning after 5 year survival was higher in YAS (rate ratio= 3.59, 95% CI: 3.46 – 3.73) and varied according to malignancy type (Table). Over the course of diagnosis, treatment and surveillance to 10 years, the average YAS was exposed to 33.8 mSv of radiation, 4.4 times the radiation exposure an individual in the general population received. 47% of YAS cumulative dose was attributed to exposure 5 years or more after diagnosis. Conclusions: YAS undergo imaging and are exposed to diagnostic irradiation at a significantly higher rate than controls even after 5 years of recurrence free survival. Alternative imaging techniques not associated with exposure to radiation should be considered for these patients. [Table: see text]

Toward Routine Use of 3D Histopathology as a Research Tool

Three-dimensional (3D) reconstruction and examination of tissue at microscopic resolution have significant potential to enhance the study of both normal and disease processes, particularly those involving structural changes or those in which the spatial relationship of disease features is important. Although other methods exist for studying tissue in 3D, using conventional histopathological features has significant advantages because it allows for conventional histopathological staining and interpretation techniques. Until now, its use has not been routine in research because of the technical difficulty in constructing 3D tissue models. We describe a novel system for 3D histological reconstruction, integrating whole-slide imaging (virtual slides), image serving, registration, and visualization into one user-friendly package. It produces high-resolution 3D reconstructions with minimal user interaction and can be used in a histopathological laboratory without input from computing specialists. It uses a novel method for slice-to-slice image registration using automatic registration algorithms custom designed for both virtual slides and histopathological images. This system has been applied to >300 separate 3D volumes from eight different tissue types, using a total of 5500 virtual slides comprising 1.45 TB of primary image data. Qualitative and quantitative metrics for the accuracy of 3D reconstruction are provided, with measured registration accuracy approaching 120 μm for a 1-cm piece of tissue. Both 3D tissue volumes and generated 3D models are presented for four demonstrator cases.