CT pelvis in children; should we routinely scan pelvis for wilms tumor and hepatoblastoma? Implications for imaging protocol development

Wilms tumor and hepatoblastoma are the most common intra-abdominal solid organ childhood tumors. CT examination is one of the routinely performed procedures in hospitals for children with these tumors inspite of high radiation exposure associated with CT scans. Sixty patients [Wilms tumor = 45, hepatoblastoma = 16] were evaluated retrospectively. Higher proportion [44.4%] of metastatic disease was identified at presentation in the Wilms tumor subset as compared to hepatoblastoma [6.3%] [p=0.006]. Metastatic disease was noted in 6 patients having Wilms tumor on follow-up while it was also low in hepatoblastoma which was noted in only 2 patients [p > 0.05]. No significant difference was identified in pelvic extension of disease at presentation in both studied population [p > 0.05]. Pelvic metastasis was noted in 1 patient only with Wilms tumor on follow-up while no pelvic metastasis was seen in the hepatoblastoma patients [p-value > 0.05]

Utility of Limited Protocol Magnetic Resonance Imaging Lumbar Spine for Nerve Root Compression in a Developing Country, Is It Accurate and Cost Effective?

STUDY DESIGN: Cross sectional study. PURPOSE: To determine the accuracy of the screening magnetic resonance study of the lumbar spine in the diagnosis of nerve root compression in cases of low back pain as compared to the routine magnetic resonance imaging (MRI) study of the lumbar spine. OVERVIEW OF LITERATURE: No local study has been conducted for this purpose. In an international study, the reported sensitivity and specificity of screening MRI lumbar spine protocol in the detection of nerve root compression are 54% and 100% respectively. METHODS: Patients of both genders older than 20 years of age with low back pain of any duration or any severity who were referred to the radiology department of Aga Khan University Hospital for MRI of their lumbar spine were evaluated. Two sets of MRI imaging were recruited for each patient: one labeled as 'screening' and the other labeled as 'routine'. The findings of screening MRI were compared with the findings of the routine MRI study. RESULTS: A total of 109 patients fulfilling the inclusion criteria were included in this study. The diagnostic accuracy, specificity and sensitivity of the screening protocol in our study was 100%, 100% and 100%, respectively in comparison with the routine MRI lumbar spine study for the detection of nerve root compression. CONCLUSIONS: Our data proved that the MRI screening study is a highly accurate tool, and its findings are comparable to the routine study for the detection of nerve root compression especially in cases of lumbar spondylosis.

[131]I-MIBG on diagnostic and therapeutic frontiers in extra-adrenal abdominal paragangliomas: a case report with mini review

Paraganglioma are tumors originating from paraganglial system and may be associated with parasympathetic [head, neck and anterior mediastinum tumors] or sympathetic [adrenal or extraadrenal or posterior mediastinal tumor] system. Majority of sympathetic paraganglioma and minority of parasympathetic tumor are functional and [131I or [132]I labeled MIBG [Meta Iodio Benzyl Guanidine] is a well established tool with good sensitivity and exceedingly high specificity. We are presenting a case report of a large extradrenal paraganglioma with extensive bony metastases and raised serum Chromogranin-A level. In this case [131]-MIBG was not only helpful in revealing the true burden of functional disease but also showed an overwhelming therapeutic response proven on post-therapy MIBG scan and normalization of serum Chromogranin-A level. This case report is followed by a mini-review about pathology, genetic mutation, diagnosis and treatment of focused on extraadrenal paragangliomas

Diffusion weighted MR imaging of ring enhancing brain lesions

To evaluate the role of diffusion weighted imaging in differentiating the cause of ring enhancing brain lesions. Analytical, descriptive study. Department of Radiology, The Aga Khan University Hospital, Karachi, from March 2007 to July 2011. Diffusion weighted imaging [DWI] was performed on 37 patients having ring enhancing lesions on their post-contrast brain MRI scans. These lesions were characterized into neoplastic and abscess cavity on the basis of diffusion restriction. Correlation of all these findings was done with histopathology obtained in all these patients. Sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of DWI were calculated. Comparisons of mean ADC values of abscess and neoplastic lesions were also done using t-test. DWI had a sensitivity of 94.73%, specificity of 94.44%, positive predictive value of 94.73%, and negative predictive value of 94.44% and diagnostic accuracy of 94.5% in differentiating brain abscess from neoplastic brain lesions. Mean ADC value in central cavity and wall of neoplastic lesions and brain abscesses were calculated with significant p-value of 0.001 and 0.025 respectively. Diffusion weighted imaging is non-invasive method with high sensitivity and specificity which can help in differentiation of ring enhancing neoplastic lesions and brain abscesses. This modality should be read in conjunction with conventional imaging

Interventions for improving research productivity in clinical radiology

The purpose of this study was to evaluate the effects of research promotion activities on overall quality and quantity of research output in a clinical department of a teaching tertiary care hospital. Simple research enhancing strategies including regular journal club, research hour, basic research skills training, hiring of research faculty, research awards, and annual research retreat and research board to increase research production were implemented in the Department of Radiology of a teaching hospital in Pakistan. A total of 77 papers were produced by the Department of Radiology before the intervention, which increased to 92 after the introduction of research initiatives. There was a significant increase in the overall proportion of publications in the international journals after the intervention [p < 0.001] with an increasing trend towards indexed journals [p < 0.001]. The research enhancing interventions had a positive effect on increasing clinical research output by the Department of Radiology. Such interventions can also be replicated in other clinical departments to increase their research productivity

MRI characterization and histopathological correlation of primary intra-axial brain glioma

Objective: To determine the diagnostic accuracy of magnetic resonance imaging [MRI] in preoperative diagnosis and grading of intra-axial gliomas compared with histopathology

Study Design: Prospective, comparative, study

Place and Duration of Study: Radiology Department, Aga Khan University Hospital, Karachi from July 2004 to June 2006

Methods: Fifty-three patients having different neurological symptoms referred to Radiology Department Aga Khan University Hospital for MRI examination were included in the study. These patients were provisionally diagnosed radiologically having intra-axial brain tumor or subsequently found to have pathologically proven primary intra-axial brain tumors. MRI scans were evaluated for location, consistency, hemorrhage, necrosis, margins, edema, MRI signals contrast enhancement and any additional features for staging the tumor. Preoperative diagnosis was compared with postoperative pathological diagnosis by using Pearson's Chi square test. Accuracy of magnetic resonance imaging in diagnosing and staging the brain tumors was determined. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of MRI in characterizing the lesion was also calculated

Results: The study included 53 patients with age ranging from 1-year 10-months to 60 years [mean 32.7 years]. Twenty-eight patients had supratentorial tumors [52%] and 25 had infratentorial tumors [47%]. Twenty-eight patients had Astrocytoma [52%], 10 had Oligodendroglioma [19%], 6 had Medulloblastoma [11%], 5 had Lymphoma [9%], and 4 had Hemangioblastoma [7%]. Preoperative MRI diagnosis was correct in 50 patients with accuracy of 94%. No significant difference was found between preoperative MRI grading and postoperative histopathological grade of intra-axial tumor [p-value>0.05]. Sensitivity, specificity, positive predictive value and negative predictive value of MRI in detecting tumor necrosis were 93%, 77%, 80% and 90% while for detecting tumor hemorrhage were 57%, 93%, 57%, and 93% respectively

Conclusion: MRI is very accurate in preoperative diagnosis, staging and assessing the tumor characteristics of primary intra-axial brain tumors. It can be used reliably in our usual clinical practice

MRI and MRV in cerebral venous thrombosis

Although Cerebral venous thrombosis is an uncommon cause of stroke among the young, it is being increasingly recognised. A prothrombotic risk factor is identified in the majority of the patients. In most instances it is seen in women in the post-partum period and those on oral contraceptives. Magnetic Resonance Imaging [MRI] has improved our ability to diagnose this condition however the variability of radiological and clinical presentation remains a challenge. MR in combination with MR venography [MRV] is the single most sensitive diagnostic technique. The MR appearance of the thrombus within the dual sinus or cortical vein is variable and is largely dependent on its age. The loss of the normal flow void on spin echo T2 images is a sensitive parameter. Thrombus on MRV is seen as loss of high flow signal from the sinus. Focal parenchymal changes occur in approximately 50% of cases and are due to oedema and infarction, with or without haemorrhage. Appearances of these lesions too are dependent on their age. Diffuse changes of raised intracranial pressure with gyral effacement may also be present