"Perifollicular rim sign" in an enlarged ovary-an additional non-contrast CT finding in ovarian torsion.

PURPOSE: To look for the presence of "perifollicular rim sign" on non-contrast CT in surgically proven cases of ovarian or adnexal torsion. METHODS: A retrospective analysis of abdominopelvic non-contrast CT examinations in surgically proven cases of ovarian or adnexal torsion was conducted seeking the presence of "perifollicular rim sign" in torsed ovaries. "Perifollicular rim sign" was defined as a complete ring of perifollicular hyperdensity around ovarian follicles with an attenuation value of > 50 HU and thickness > 1-2 mm. A positive sign was equated to the presence of perifollicular hemorrhage. Pre-operative non-contrast CT was available in 7 out of the 39 ovarian or adnexal torsions included in our study. RESULTS: "Perifollicular rim sign" was present in 5 out of the 7 ovarian torsions on pre-operative non-contrast CT. MRI correlation was available in one patient. Ovarian enlargement (>4 cm) was present in all 7 cases. CONCLUSION: In an appropriate clinical setting, presence of "perifollicular rim sign" in an enlarged ovary on non-contrast CT examination can be considered a useful additional sign for ovarian torsion.

Diagnostic performance of multi-parametric MRI to differentiate benign sex cord stromal tumors from malignant (non-stromal and stromal) testicular neoplasms.

PURPOSE: Testicular stromal tumors are uncommon, although mostly benign. The purpose of this study is to assess the role of multi-parametric MRI in differentiating benign testicular stromal tumors from malignant testicular neoplasms (non-stromal and stromal). METHODS: A single-center retrospective study comparing benign stromal tumors (STs) to malignant testicular neoplasms (MTNs) was conducted. MR imaging assessment included tumor size, T2- and T1-weighted signal intensity, T2- and T1-weighted texture pattern, diffusion restriction, presence of hemorrhage and/or necrosis, and measurement of apparent diffusion coefficient and dynamic contrast enhancement (DCE). Inter-observer agreement was assessed using Cohen's kappa and Bland-Altman and data were compared using independent t-tests or χ2. Receiver operating characteristic curve analysis was used to test models incorporating various imaging features. RESULTS: Radical orchiectomy and histopathology revealed 20 testicular neoplasms: seven STs (35%) and thirteen MTNs (65%). MTNs were significantly larger in size than STs (5.1 ± 2.36 cm vs. 1.27 ± 0.56 cm; p-value < 0.001). STs demonstrated more hypointense T2W signal (85.7% vs. 46.2%; p-value < 0.09), less T2W heterogeneous texture (14.3% vs. 61.5%; p-value < 0.04), and less diffusion restriction (16.7% vs. 83.3%; p-value < 0.01) in comparison to MTNs. STs demonstrated mainly homogenous post-contrast enhancement pattern (71.4% vs. 7.7%; p-value < 0.004), while MTNs showed primarily heterogeneous enhancement pattern (77% vs. 14.3%; p-value < 0.02). STs revealed greater corrected venous phase enhancement (STs: 0.59 ± 0.29; MTNs: 0.25 ± 0.25; p-value < 0.03). STs showed higher ADC values, though the difference was not statistically significant (p-value < 0.25). A model combining T2W, DWI, and DCE features showed the best overall diagnostic accuracy with area under ROC curve of 0.99 and confidence interval ranging from 0.94 to 1. CONCLUSION: Multi-parametric MRI can potentially differentiate benign stromal tumors from malignant testicular neoplasms, which can help to avoid radical orchiectomy. However, future studies using larger sample sizes are needed to validate our results.

Idiopathic Retroperitoneal Non-pancreatic Pseudocyst in an Adult Male: Radiological Images and Surgical Video of Laparoscopic Excision.

Retroperitoneal pseudocyst (RPC) is an uncommon surgical entity. The pseudocyst is characterized by the absence of epithelial lining in the cyst wall. Mostly, it occurs as a sequela of pancreatitis. Pseudocyst due to a non-pancreatic cause, however, is very rare. We report a 49-year-old male, who presented to the emergency department with moderate intensity lower abdominal pain. Computed tomography scans revealed a huge retroperitoneal cyst which was overlying the right ureter and right iliac vessels. The patient underwent laparoscopic excision of the cyst and recovered without any complications. Histopathological examination showed a non-pancreatic RPC. In conclusion, non-pancreatic RPC is a rare surgical disease which can result in pressure symptoms depending on its location and size. In our patient, it was treated by laparoscopic excision despite its proximity to iliac vessels and ureter. A laparoscopic approach using safe surgical principles is a viable option for non-pancreatic RPC. The proximity of the lesion to the iliac vessels and the ureter can be carefully navigated safely by laparoscopy. The ureter can be confirmed by stimulating peristalsis of the duct when in doubt.

Gallbladder volvulus with segmental right liver lobe hypoplasia/atrophy: a preoperative diagnostic dilemma.

Gallbladder volvulus (GBV) due to rotation of the gall bladder (GB) around its own mesentery is a rare surgical emergency and often identified intraoperatively. Typically, cholecystitis is the initial clinical diagnosis, but a high index of suspicion on imaging can alert the physician for the possibility of GBV requiring urgent surgical intervention. We describe a case of a young female patient with hypoplasia/atrophy of the posterior segment of the right liver lobe and a GB with no hepatic attachments but only mesenteric pedicle. She presented with first episode of sudden-onset, severe right subcostal pain. The ultrasonogram and magnetic resonance cholangiopancreatogram findings were suggestive of GBV. She underwent laparoscopic exploration that confirmed GBV of a free-floating GB with a thrombosed cystic artery. The GB was detorted, and cholecystectomy was performed. She had an uneventful postoperative course and was discharged with no complications. Histopathological examination showed intramural haematoma of the GB with wall necrosis.

CNS aspergilloma mimicking tumors: Review of CNS aspergillus infection imaging characteristics in the immunocompetent population.

BACKGROUND AND PURPOSE: CNS Aspergillosis is very rare and difficult to diagnose clinically and on imaging. Our objective was to elucidate distinct neuroimaging pattern of CNS aspergillosis in the immunocompetent population that helps to differentiate from other differential diagnosis. METHODS: Retrospective analysis of brain imaging findings was performed in eight proven cases of central nervous system aspergillosis in immunocompetent patients. Immunocompetent status was screened with clinical and radiological information. Cases were evaluated for anatomical distribution, T1 and T2 signal pattern in MRI and attenuation characteristics in CT scan, post-contrast enhancement pattern, internal inhomogeneity, vascular involvement, calvarial involvement and concomitant paranasal, cavernous sinus or orbital extension. All patients were operated and diagnosis was confirmed on histopathology. RESULTS: The age range was 19-50 years with mean age of 33.7 years. Concomitant sinonasal disease was seen in six patients (75%). Three patients had orbital extensions. Most of the lesions (n=7) were profoundly hypointense in T2-weighted imaging. The most common enhancement pattern was bright, solid and homogenous enhancement (n=7). Cavernous extension with ICA encasement was always associated with paranasal sinus disease. Six patients showed demineralization or complete resorption of involved bone. All of the fungal masses appear hyperdense on available CT scan images. CONCLUSION: CNS aspergillus infection in immunocompetent patients has distinct imaging features as compared to CNS aspergillosis in immunocompromised patients. A high index of suspicion in proper clinical settings, even with immunocompetent status and typical imaging features allow us to diagnose CNS aspergillosis in such patients.

Multi-parametric (mp) MRI for the diagnosis of abdominal wall desmoid tumors.

INTRODUCTION: Desmoid tumors are benign myofibroblastic neoplasms, originating from the muscle aponeurosis and classified as deep fibromatoses. The aim of this study was to evaluate the utility of multi-parametric (mp)-MRI for the diagnosis of abdominal wall desmoid tumor (awdt). MATERIAL AND METHODS: This Institutional review board approved retrospective study compared 10 patients (mean age±SD; 38.2±13years; 9 females and 1 male) with awdt to 14 subjects (mean age±SD; 45.6±14.7years; 9 females and 5 males) with non-desmoid abdominal wall tumors (ndawt). All included subjects underwent mp-MRI, which included conventional, diffusion weighted and dynamic contrast-enhanced (DCE) MRI. Two blinded experienced fellowship trained radiologists (MK and SR) evaluated each lesion characteristics qualitatively and quantitatively which included margin, homogeneity, T2W/T1W signal intensity (SI), T2 dark strands, and fascial tail together with measurements of apparent diffusion coefficient (ADC) and semi-quantitative DCE analysis. Inter-observer agreement was assessed using Cohen's kappa and data were compared between groups using independent sample t-tests and Chi-square tests. RESULTS: No significant differences in age or gender appeared between groups. On qualitative analysis, T2 dark strands were identified in 90% by both radiologist (K=0.82) of awdt, while fascial tail was identified in 70% by radiologist 1 and 80% by second radiologist (k=0.91) of awdt; however no other lesions showed these findings. Other subjective imaging findings did not significantly differ between groups with moderate-to-strong agreements (k=0.7-1.0). On quantitative measurements, diffusion imaging awdt lesions showed higher mean ADC value compared to other lesions, although it did not reached at the level of significance. While on DCE MRI, all awdt lesions showed type 1 (progressive) DCE curve, however no significant difference was observed between groups. CONCLUSIONS: T2 dark strands and fascial tail are characteristic features of awdt, whereas other subjective/qualitative findings are not useful. Quantitative findings such as ADC measurements and DCE curve analysis may have additional value to differentiate awdt from ndawt, but will require further analysis.

Multi-modality imaging review of congenital abnormalities of kidney and upper urinary tract.

Congenital abnormalities of the kidney and urinary tract (CAKUT) include a wide range of abnormalities ranging from asymptomatic ectopic kidneys to life threatening renal agenesis (bilateral). Many of them are detected in the antenatal or immediate postnatal with a significant proportion identified in the adult population with varying degree of severity. CAKUT can be classified on embryological basis in to abnormalities in the renal parenchymal development, aberrant embryonic migration and abnormalities of the collecting system. Renal parenchymal abnormalities include multi cystic dysplastic kidneys, renal hypoplasia, number (agenesis or supernumerary), shape and cystic renal diseases. Aberrant embryonic migration encompasses abnormal location and fusion anomalies. Collecting system abnormalities include duplex kidneys and Pelvi ureteric junction obstruction. Ultrasonography (US) is typically the first imaging performed as it is easily available, non-invasive and radiation free used both antenatally and postnatally. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful to confirm the ultrasound detected abnormality, detection of complex malformations, demonstration of collecting system and vascular anatomy and more importantly for early detection of complications like renal calculi, infection and malignancies. As CAKUT are one of the leading causes of end stage renal disease, it is important for the radiologists to be familiar with the varying imaging appearances of CAKUT on US, CT and MRI, thereby helping in prompt diagnosis and optimal management.

Down the wrong road - a case report of inadvertent nasogastric tube insertion leading to lung laceration and important pearls to avoid complications.

Nasogastric tube (NGT) insertion is a common procedure performed by residents and nursing staff to access the stomach. Although an apparently simple procedure, it is associated with technical difficulties and complications if proper care is not taken during insertion. We present a case of a 79-year-old female with multiple comorbidities who had a percutaneous enteral gastrostomy tube removed due to infection of an insertion site wound and a NGT was inserted for feeding. A few minutes post-insertion the patient developed shortness of breath and a drop in oxygen saturation. An immediate chest X-ray showed the NG tube traversing along the course of the trachea and the right main bronchus into the right upper abdomen with right-sided pneumothorax. The NG tube was immediately removed and a right chest drain inserted. Subsequent imaging showed right-sided pneumothorax with evidence of lung laceration and underlying lung collapse and diaphragmatic injury. The patient underwent a prolonged course of hospitalisation due to hospital-acquired pneumonia before being discharged upon clinical improvement. We highlight the fact that a simple and routine procedure such as NGT insertion can have devastating complications if due care is not taken. Along with a literature review, we provide and compare different methods to confirm correct placement of a NGT. The article also discusses important pearls for practising physicians and nursing staff to avoid such complications. Owing to the frequency of the procedure in hospitals and long-term care units, appropriate awareness among medical staff is necessary.

False positive and false negative diagnoses of prostate cancer at multi-parametric prostate MRI in active surveillance.

MP-MRI is a critical component in active surveillance (AS) of prostate cancer (PCa) because of a high negative predictive value for clinically significant tumours. This review illustrates pitfalls of MP-MRI and how to recognise and avoid them. The anterior fibromuscular stroma and central zone are low signal on T2W-MRI/apparent diffusion coefficient (ADC), resembling PCa. Location, progressive enhancement and low signal on b ≥1000 mm²/s echo-planar images (EPI) are differentiating features. BPH can mimic PCa. Glandular BPH shows increased T2W/ADC signal, cystic change and progressive enhancement; however, stromal BPH resembles transition zone (TZ) PCa. A rounded morphology, low T2 signal capsule and posterior/superior location favour stromal BPH. Acute/chronic prostatitis mimics PCa at MP-MRI, with differentiation mainly on clinical grounds. Visual analysis of diffusion-weighted MRI must include EPI and appropriate windowing of ADC. Quantitative ADC analysis is limited by lack of standardization; the ADC ratio and ADC histogram analysis are alternatives to mean values. DCE lacks standardisation and has limited utility in the TZ, where T2W/DWI are favoured. Targeted TRUS-guided biopsies of MR-detected lesions are challenging. Lesions detected on MP-MRI may not be perfectly targeted with TRUS and this must be considered when faced with a suspicious lesion on MP-MRI and a negative targeted TRUS biopsy histopathological result. KEYPOINTS: • Multi-parametric MRI plays a critical role in prostate cancer active surveillance. • Low T2W signal intensity structures appear dark on ADC, potentially simulating cancer. • Stromal BPH mimics cancer at DWI and DCE. • Long b value trace EPI should be reviewed • Targeted biopsy of MR-detected lesions using TRUS guidance may be challenging.

Current updates on the molecular genetics and magnetic resonance imaging of focal nodular hyperplasia and hepatocellular adenoma.

UNLABELLED: Focal nodular hyperplasia (FNH) and hepatocellular adenomas (HCAs) constitute benign hepatic neoplasms in adults. HCAs are monoclonal neoplasms characterised by an increased predilection to haemorrhage and also malignant transformation. On the other hand, FNH is a polyclonal tumour-like lesion that occurs in response to increased perfusion and has an uneventful clinical course. Recent advances in molecular genetics and genotype-phenotype correlation in these hepatocellular neoplasms have enabled a new classification system. FNHs are classified into the typical and atypical types based on histomorphological and imaging features. HCAs have been categorised into four subtypes: (1) HCAs with HNF-1α mutations are diffusely steatotic, do not undergo malignant transformation, and are associated with familial diabetes or adenomatosis. (2) Inflammatory HCAs are hypervascular with marked peliosis and a tendency to bleed. They are associated with obesity, alcohol and hepatic steatosis. (3) HCAs with ß-catenin mutations are associated with male hormone administration and glycogen storage disease, frequently undergo malignant transformation and may simulate hepatocellular carcinoma on imaging. (4) The final type is unclassified HCAs. Each of these except the unclassified subtype has a few distinct imaging features, often enabling reasonably accurate diagnosis. Biopsy with immunohistochemical analysis is helpful in difficult cases and has strong implications for patient management. TEACHING POINTS: • FNHs are benign polyclonal neoplasms with no risk of haemorrhage or malignancy. • HCAs are benign monoclonal neoplasms classified into four subtypes based on immunohistochemistry. • Inflammatory HCAs show an atoll sign with a risk of bleeding and malignant transformation. • HNF-1α HCAs are steatotic HCAs with minimal complications and the best prognosis. • ß-Catenin HCA shows variable MRI features and a high risk of malignancy.

Diagnostic accuracy of dual-echo (in- and opposed-phase) T1-weighted gradient recalled echo for detection and grading of hepatic iron using quantitative and visual assessment.

OBJECTIVES: Detection and quantification of hepatic iron with dual-echo gradient recalled echo (GRE) has been proposed as a rapid alternative to other magnetic resonance imaging (MRI) techniques. Co-existing steatosis and T1 weighting are limitations. This study assesses the accuracy of routine dual-echo GRE. METHODOLOGY: Between 2010 and 2013, 109 consecutive patients underwent multi-echo (ME) MRI and dual-echo GRE for quantification of hepatic iron. Liver iron concentration (LIC) was calculated from ME-MRI. Relative signal intensity (RSI) and fat signal fraction (FSF) were calculated from dual-echo GRE. Four radiologists subjectively evaluated dual-echo GRE (±subtraction). Diagnostic accuracy was compared between techniques and correlated with biopsy using Fisher's exact test, Spearman correlation and regression. RESULTS: The sensitivity of visual detection of iron ranged from 48 to 55%. Subtraction did not increase sensitivity (p < 0.001). Inter-observer variability was substantial (κ = 0.72). The specificity of visual detection of iron approached 100% with false-positive diagnoses observed using subtraction. LIC showed a higher correlation with histopathological iron grade (r = 0.94, p < 0.001) compared with RSI (r = 0.65, p = 0.02). Univariate regression showed an association between RSI and LIC (B = 0.98, p < 0.001, CI 0.73-1.23); however, the association was not significant with multi-variate regression including FSF (p = 0.28). CONCLUSIONS: Dual-echo GRE has low sensitivity for hepatic iron. Subtraction imaging can result in false-positive diagnoses. KEY POINTS: • Routine liver MRI studies cannot effectively screen patients for iron overload. • Concomitant hepatic steatosis and iron limits diagnostic accuracy of routine liver MRI. • Dual-echo GRE subtraction imaging causes false-positive diagnoses of iron overload. • Dedicated MRI techniques should be used to diagnose and quantify iron overload.

Aneurysmal bone cyst of the ethmoid sinus: A case report.

BACKGROUND: Aneurysmal bone cyst is an expansile bone lesion, non-neoplastic in nature, occurring most commonly in long bones. It is uncommon in facial bones and exceptionally rare in ethmoid bone. Ten cases of aneurysmal bone cysts of ethmoid bone have been reported so far. CASE REPORT: A young adolescent presented with decreased vision and pain in the right eye. MRI revealed an expansile lesion having conspicuous fluid levels with a multiloculated appearance in the right ethmoid bone extending to the right orbit. CT was done to characterize better bone details. Both biopsy of the lesion and histopathology of resected specimen confirmed aneurysmal bone cyst. CONCLUSIONS: A characteristic appearance on MRI and CT examinations helped to confidently diagnose a relatively common lesion in an exceedingly rare location.

Cemento-ossifying Fibroma Of Paranasal Sinus Presenting Acutely As Orbital Cellulitis.

Fibro-osseous lesions of the face and paranasal sinuses are relatively uncommon. These lesions have overlapping clinical, radiologic and pathologic features causing difficulty in diagnosis. Neoplastic fibro-osseous paranasal sinus lesions can be benign or malignant. The benign fibro-osseous lesions described are: ossifying fibroma (and its histologic variants) and fibrous dysplasia. The variants of ossifying fibroma differ in the nature of calcified material (i.e. cementum versus bone), in the location of the lesion (oral versus paranasal sinus or orbital), other morphologic variations (presence of psammomatoid concretions) and biologic behavior (aggressive versus stable). Presence of cementum or bone classifies the lesion as cementifying fibroma or ossifying fibroma respectively while lesions with mixture of both cementum and bone are called cemento-ossifying fibroma. We describe a case of a young adult male with cemento-ossifying fibroma of paranasal sinus presenting acutely as left orbital cellulitis with proptosis.

Primary Burkitt's Lymphoma Of The Appendix Presenting As Acute Abdomen: A Case Report.

Leukemic and lymphomatous involvement of the appendix is rare and even rarer is its presentation as appendicitis. Burkitt's lymphoma is a high grade B-cell neoplasm. Its non-endemic form typically presents as abdominal mass in children. This rapidly growing tumour may cause symptoms due to mass effect or direct involvement of the bowel. Clinical presentations like acute abdomen can be secondary to intestinal obstruction, intussusception or sometimes perforation.We describe here a case of an adult male with an unusual presentation of appendiceal Burkitt's lymphoma mimicking acute cholecystitis or appendicitis.