Neuroimaging Findings in COVID-19 Associated Rhino-Orbital-Cerebral Mucormycosis: A Review.

The involvement of the neurological system by coronavirus has been well established. Since its onset, the systemic manifestations of coronavirus disease 2019 (COVID-19) have been evolving rapidly and imaging plays a pivotal role in diagnosing the various primary and secondary effects of the disease. As the pandemic continues to defy human civilization, secondary impacts of the disease and the treatment given to patients afflicted with the disease have stemmed up. Rhino-orbital-cerebral mucormycosis is one such potentially dangerous infection now commonly seen in COVID-19 patients, especially the ones treated with immunosuppressants. Early diagnosis is key for COVID-19-associated mucormycosis (CAM), and radiologists should be well aware of its alarming neurological manifestations from the involvement of parenchyma, meninges, vessels, cranial nerves, and skull base. This review highlights the magnetic resonance imaging features of neuraxial involvement in CAM.

Conventional uroradiology with excretory urography: a forgotten art?

Excretory urography (EU) had been the most frequently performed imaging modality for uroradiology in the past. With the advances in ultrasonography, and development of cross-sectional urography with CT and MRI, EU is now seldom performed. Consequently, there has been a decline of expertise in this technique. However, EU has multiple advantages such as dynamic nature, easy availability, low cost and radiation burden. These render it potentially very valuable in specific indications like congenital anomalies, urothelial lesions and urinary leaks. This review intends to emphasize the current day relevance of excretory urography, outline the key points of the technique, and describe the pearls and pitfalls of interpretation.

Role of MRI in diagnosing the primary site of origin in indeterminate cases of uterocervical carcinomas: a systematic review and meta-analysis.

OBJECTIVE: To perform a literature review assessing role of MRI in predicting origin of indeterminate uterocervical carcinomas with emphasis on sequences and imaging parameters. METHODS: Electronic literature search of PubMed was performed from its inception until May 2020 and PICO model used for study selection; population was female patients with known/clinical suspicion of uterocervical cancer, intervention was MRI, comparison was by histopathology and outcome was differentiation between primary endometrial and cervical cancers. RESULTS: Eight out of nine reviewed articles reinforced role of MRI in uterocervical primary determination. T2 and Dynamic contrast were the most popular sequences determining tumor location, morphology, enhancement, and invasion patterns. Role of DWI and MR spectroscopy has been evaluated by even fewer studies with significant differences found in both apparent diffusion coefficient values and metabolite spectra. The four studies eligible for meta-analysis showed a pooled sensitivity of 88.4% (95% confidence interval 70.6 to 96.1%) and a pooled specificity of 39.5% (95% confidence interval 4.2 to 90.6%). CONCLUSIONS: MRI plays a pivotal role in uterocervical primary determination with both conventional and newer sequences assessing important morphometric and functional parameters. Socioeconomic impact of both primaries, different management guidelines and paucity of existing studies warrants further research. Prospective multicenter trials will help bridge this gap. Meanwhile, individual patient database meta-analysis can help corroborate existing data. ADVANCES IN KNOWLEDGE: MRI with its classical and functional sequences helps in differentiation of the uterine 'cancer gray zone' which is imperative as both primary endometrial and cervical tumors have different management protocols.

Unveiling the tale of the tail: an illustration of spinal dysraphisms.

Spinal dysraphism is an umbrella term describing herniation of meninges or neural elements through defective neural arch. They can be broadly categorized into open and closed types. MRI is the investigation of choice to study neural abnormalities and to assess the severity of hydrocephalus and Chiari malformation. Knowledge of the embryology of these disorders is valuable in correctly identifying the type of dysraphism. The aim of surgery is untethering and dural reconstruction. Accurate depiction of the abnormal anatomy in cases of spinal dysraphism is of utmost importance for surgical management of these patients. MRI makes this possible due to its excellent soft tissue contrast resolution and multiplanar capability, allowing the radiologist to evaluate the intricate details in small pediatric spinal structures. Imaging enlightens the surgeons about the status of spinal cord and other associated abnormalities and helps detect re-tethering in operated cases. Besides, antenatal surgery to repair myelomeningoceles has made detection of open dysraphisms on fetal MRI and antenatal ultrasound critical. The purpose of this review is to describe the development of spine, illustrate the myriad imaging features of open and closed spinal dysraphisms, and enlist the reporting points the operating surgeon seeks from the radiologist.

MRI in intracranial tuberculosis: Have we seen it all?

Tuberculosis is emerging worldwide across diverse populations and geographies; unrestricted by the social divide and the geographical barriers in today's interconnected world. This rise in its prevalence can be linked to multiple factors including urbanisation, spurt in global travel, population explosion, migration and HIV infection. The varied and complex clinical presentation of intracranial tuberculosis tricks even the best of the clinicians. This along with the other facets associated with its management including drug resistance, paradoxical reaction, underlying HIV infection can make it particularly challenging. Imaging has a definitive role in the evaluation and follow-up of intracranial tuberculosis and MRI is the cornerstone in this regard. Typical features of intracranial tuberculosis are well-described. However, it is not infrequent to encounter atypical and bizarre presentations, both clinically and on imaging. A holistic clinical and imaging review of difficult cases, including newer MRI techniques, is necessary for the neuroradiologist, neurologist and the neurosurgeon to arrive at the right diagnosis in a timely fashion.

A journey through formation and malformations of the neo-cortex.

PURPOSE: Malformations of cortical development (MCD) are a heterogeneous group of disorders characterized by abnormal structure of the cerebral cortex. MCDs are an important cause of development delay and intractable epilepsy in children. In this review, we explore the embryological stages of development of neo-cortex, the imageology of various malformations which may occur during the journey of this development, the recent advances in imaging techniques used for diagnosing these malformations, and finally a simplified radiological approach to malformations of cortical development. REVIEW: We discuss the classification of MCD according to the embryologic stage of cerebral cortex at which the abnormality occurred and the unique imaging features of various malformations, including microcephaly, hemimegalencephaly, lissencephaly, focal cortical dysplasia, heterotopias, polymicrogyria, schizencephaly, and neonatal CMV infection. Also, a rare variant of hemimegalencephaly, namely posterior quadrantic dysplasia, is illustrated; the diagnosis of which is crucial for neurosurgeons to decide management. The technological advancement in the imaging of MCD has taken a leap in the recent years. Imaging now also plays an enormous role in mapping of the abnormalities, delineation of proper surgical boundaries, and quantifying risks of visual, language, and sensorimotor dysfunction. With the introduction of various motor-sparing surgeries and disconnection procedures, proper identification and delineation of these malformations have gained utmost significance. CONCLUSION: Knowledge of the wide imaging spectrum of MCD, familiarity with recent advances in imaging and an optimal radiological approach is essential for the general radiologist to accurately diagnose and prognosticate MCD as well as provide the best surgical approach to the operating surgeon.

Multiple intrahepatic pancreatic pseudocyst (MIHPPs): an overlooked and misdiagnosed entity.

Pancreatitis and pseudo-pancreatic cysts are frequently encountered entities; however, intrahepatic pseudocysts presenting as large number of liver cysts with absence of overt signs of pancreatitis has never been reported in literature. Here, we report an interesting case of multiple intrahepatic pancreatic pseudocysts (MIHPPs), a challenging diagnosis to be kept in mind while dealing with complex cystic lesions of liver. Pseudocysts are common complication of pancreatitis, often these are located within the vicinity of the pancreas in the lesser sac and the retroperitoneum. Extra pancreatic location of these cysts within the liver is a diagnosis often missed, with only 50 odd cases reported in literature till date. Most of these reported cases are either subcapsular in location or limited in number to one or two lesions. Although rare, possibility of MIHPPs is an important diagnosis that should be kept in mind while considering list of differentials for complex cystic lesions of the liver even in the absence of overt signs of pancreatitis.

MRI evaluation of pelvis in Mayer-Rokitansky-Kuster-Hauser syndrome: interobserver agreement for surgically relevant structures.

OBJECTIVES: Diagnostic role of MRI in Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is well documented. Recent studies have shown the relevance of MRI in detailing the pelvic anatomy, particularly small Mullerian remnants. The results are, however, not consistent and reproducibility of MRI features has not been confirmed. The aim of our study was to evaluate the detailed pelvic anatomy in patients with MRKH syndrome and to calculate the interobserver agreement of the MRI features. METHODS: The study was carried out on female patients, aged 15-30 years, with primary amenorrhea. Following clinical, gynaecological, endocrinological, ultrasound and chromosomal work-up and a provisional diagnosis of MRKH syndrome, MRI pelvis was performed on 25 patients using a 1.5 T scanner. MRI images were retrospectively reviewed by two radiologists for a detailed evaluation of Mullerian structures (uterine buds, fibrous bands, midline triangular soft tissue), vagina, and ovaries. κ coefficient was calculated as a measure of interobserver agreement. RESULTS: Interobserver agreement was good to excellent (κ: 0.7788 ± 0.2168 to 1 ± 0) for uterine buds and their characteristics, vagina, ovaries and associated renal/vertebral anomalies; poor to fair for fibrous bands (κ: 0.2857 ± 0.3273 to 0.6032 ± 0.2149) and good for midline triangular soft tissue (κ: 0.7826 ± 0.1474). CONCLUSION: MRI is capable of providing key pre-operative anatomical information in MRKH syndrome non-invasively. There is good to excellent interobserver agreement for MRI features of most of the surgical relevant structures. ADVANCES IN KNOWLEDGE: MRI features of salient preoperative anatomical structures are reproducible between observers.

Popliteal neurovascular bundle is safe during inside-out repair of medial meniscus without a safety incision.

PURPOSE: There is a theoretical risk of injury to neurovascular structures during inside-out meniscal repair without a safety incision, although there are limited studies assessing this risk. This simulation study on archival MRI films was performed to assess the risk for the popliteal neurovascular bundle and the peroneal nerve during passage of needles for inside-out meniscus repair without a "safety incision", thereby defining a "safe zone" of the menisci that can be safely repaired using this technique. METHODS: Archival MRI scans (n = 50) were retrieved and axial sections through the menisci were used for simulation. The needle passage was simulated for different points on the posterior horn and body of lateral and medial menisci at "half-hour" intervals using clock method (15° intervals) with three different portals and two different needle cannulas, resulting in six different scenarios of needle passage for each point on the meniscus. The distance of the needle in each scenario was measured from popliteal vessels (n = 50) and peroneal nerve (n = 10). The value "mean-3SD" was calculated for positive means and "Mean + 3SD" was calculated if the mean was negative. An additional 2 mm was defined as "safe distance". Thus, simulation models in which the mean - 3SD was less than 2 mm (or mean + 3SD was greater than - 2 mm for negative means) were labelled as "unsafe". RESULTS: Needle passage through medial meniscus at and medial to 1 o'clock position for a right knee (or 11 o'clock position for a left knee) was safe, irrespective of the portal and needle type. For the lateral meniscus, only the equatorial region was found to be safe with this method. CONCLUSIONS: The popliteal neurovascular bundle is safe during the inside-out medial meniscal repair without a safety incision. For the terminal-most part of the posterior horn, the AM portal and the straight cannula should be avoided. However, this method without safety incision cannot be recommended for lateral meniscus because of the risk to the popliteal vessels and the peroneal nerve. Instead, the inside-out method with a safety incision, or an all-inside method should be used for lateral meniscus. LEVEL OF EVIDENCE: III.

Posterior Quadrantic Dysplasia: MRI Diagnosis of a Lesser Known Cause of Pediatric Intractable Epilepsy.

Posterior quadrantic dysplasia (PQD) is a rare cause of pediatric intractable epilepsy. It is a sporadic cortical development malformation that involves the posterior three lobes of a single hemisphere and spares the frontal cortex. Very few cases have been reported in the literature, mostly as anecdotal reports or as a part of large series of refractory epilepsy. It is essential to know about this lesser known entity and differentiate it from other more common similar anomalies such as multilobar cortical dysplasia and hemimegalencephaly as new motor-sparing neurosurgical disconnective procedures have led to dramatically reduced mortality and morbidity rates, apart from gifting the affected children a better quality of life. Magnetic resonance imaging (MRI) is pivotal in astute diagnosis of the condition and accurate delineation of boundaries of the lesion to aid in neurosurgical management. We report one such case of PQD presenting with refractory epilepsy, which was diagnosed on MRI.