Bladder paragangliomas: a pictorial review.

Bladder paragangliomas (bPGL) are rare neuroendocrine tumors arising from the sympathetic paraganglia present in the bladder wall. Bladder PGLs are typically submucosal or intramural but when subserosal may not be readily visible at cystoscopy. The average size at presentation is 3.9 cm (range 1.0-9.1 cm). When small, bPGL are usually spherical, well-marginated and homogeneous. Larger bPGL are typically more complex with peri- and intra-tumoral neovascularity and central necrosis. On ultrasound, increased color Doppler signal is typical. The increased soft tissue resolution of MRI enables localization of bPGL within the bladder wall more accurately than CT. Restricted diffusion and avid contrast enhancement help differentiate small bPGLs from leiomyomas, which have similar appearances on ultrasound and CT. Nuclear medicine techniques identify bPGLs and their metastases with high specificity, 68Ga-DOTATATE PET/CT having largely replaced 123I-mIBG SPECT/CT as the first line functional investigation. Imaging is essential to aid surgical planning, as endoscopic resection is often not possible or incomplete due to tumor location. For patients with advanced disease, 68Ga-DOTATATE PET/CT and 123I-mIBG SPECT/CT assess suitability for peptide receptor radionuclide therapy. Up to 63% of bPGL patients have a germline mutation, most commonly in the SDHB subunit gene, increasing their risk of developing pheochromocytomas and further paragangliomas; lifelong annual biochemical and periodic imaging screening from skull base to pelvis is therefore recommended.

Tumour detection and outcomes of surveillance screening in SDHB and SDHD pathogenic variant carriers.

OBJECTIVE: Succinate dehydrogenase subunit (SDHx) pathogenic variants predispose to phaeochromocytoma and paraganglioma (PPGL). Lifelong surveillance is recommended for all patients to enable prompt detection and treatment. There is currently limited evidence for optimal surveillance strategies in hereditary PPGL. We aim to detail the clinical presentation of PPGL in our cohort of non-index SDHB and SDHD pathogenic variant carriers. METHODS: Retrospective analysis of medical and genetic records from a single tertiary referral centre identified SDHB or SDHD pathogenic variants in 74 non-index cases (56 SDHB and 18 SDHD). Surveillance screening for asymptomatic relatives consisted of annual plasma metanephrine measurement and whole-body MRI with contrast at 3-5 yearly intervals. RESULTS: Twenty-three out of 74 non-index patients (10 SDHB and 13 SDHD) were diagnosed with PPGL, 17 patients through surveillance screening (24 tumours in total) and 6 diagnosed prior to commencement of cascade screening with symptomatic presentation. MRI with contrast identified PPGL in 22/24 screen-detected tumours and 5/24 tumours had elevated plasma metanephrine levels. Penetrance in non-index family members was 15.2 and 47.2% for SDHB carriers and 71.6 and 78.7% for SDHD carriers at age of 50 and 70 years, respectively. CONCLUSION: Surveillance screening with combined biochemical testing and imaging enables early detection of PPGL in asymptomatic relatives with SDHx pathogenic variants. The presence of disease at first screen was significant in our cohort and hence further multi-centre long-term data are needed to inform counselling of family members undergoing lifelong surveillance.

Maternal and fetal incidental findings on antenatal magnetic resonance imaging.

BACKGROUND: Magnetic resonance imaging (MRI) examinations are increasingly used in antenatal clinical practice. Incidental findings are a recognized association with imaging and although in some circumstances their identification can alter management, they are often associated with increased anxiety, for both patient and clinician, as well as increased health care costs. OBJECTIVE: This study aimed to evaluate the incidence of unexpected findings in both the mother and fetus during antenatal MRI examinations. MATERIALS AND METHODS: A retrospective study was undertaken over a five-year period at St.. Thomas' Hospital in London. Maternal incidental findings were recorded from all clinical reports of all fetal MRIs performed (for clinical reasons and in healthy volunteers) during this period. Fetal incidental findings were recorded only in cases where women with uncomplicated pregnancies were participating as healthy volunteers. RESULTS: A total of 2,569 MRIs were included; 17% of women had maternal incidental findings. Of these, 1,099 were women with uncomplicated pregnancies who undertook research MRIs as healthy volunteers; fetal incidental findings were identified in 12.3%. CONCLUSION: Incidental findings are a common occurrence in antenatal MRI. Consideration should be given to counseling women appropriately before imaging and ensuring that robust local protocols are in place for follow-up and further management of such cases.

Imaging Features of Succinate Dehydrogenase-deficient Pheochromocytoma-Paraganglioma Syndromes.

Pheochromocytoma (PC) and paraganglioma (PGL) are rare neuroendocrine tumors that occur throughout the body from the base of the skull to the pelvis. Sympathetic catecholamine-secreting tumors may be associated with hyperadrenergic symptoms and long-term morbidity if they are untreated. Typically biochemically silent, head and neck PGLs may result in cranial nerve palsies and symptoms due to localized mass effect. Tumors can arise sporadically or as part of an inheritable PC-PGL syndrome. Up to 40% of tumors are recognized to be associated with germline mutations in an increasing array of susceptibility genes, including those that appear to arise sporadically. Most commonly, up to 25% of all PC-PGLs are associated with mutations in one of the succinate dehydrogenase (SDH) enzyme subunit genes. The resulting familial PC-PGL syndrome varies according to the affected enzyme subunit (most commonly SDHB and SDHD mutations) with respect to tumor prevalence, location, age of onset, and risk of malignancy. Patients with SDH enzyme mutations have increased lifetime risk of developing multifocal tumors and malignancy. Early recognition of individuals at high risk, genetic testing, screening of family members, and lifelong surveillance programs are recommended, but not without health, economic, and psychologic implications. Anatomic and functional imaging is key to diagnosis, staging, treatment planning, and lifelong surveillance of these individuals. Radiologists must be aware of the imaging appearance of these varied tumors.©RSNA, 2019.

Radiology of benign disorders of menstruation.

Menstrual complaints are common and include pain, abnormal bleeding, and menstrual irregularity. The etiology is wide-ranging and includes endometriosis, fibroids, adenomyosis, pelvic congestion syndrome, pelvic inflammatory disease, endometrial hyperplasia, and polyps. Polycystic ovarian syndrome and some congenital uterine anomalies may present with menstrual disturbance and have been included in this review. Transvaginal ultrasound is widely used as first-line investigation. Magnetic resonance imaging is used increasingly with high diagnostic accuracy and confidence. Its multiplanar capacity and superior tissue contrast resolution enable accurate presurgical mapping of fibroids, deep pelvic endometriosis, and adenomyosis. Similarly, accurate differentiation of congenital uterine anomalies depends on multiplanar imaging with either 3-dimensional ultrasound or magnetic resonance imaging. Recent advances in imaging and radiological intervention, combined with an understanding of the underlying causes of menstrual dysfunction, therefore aid in accurate diagnosis and optimal treatment planning.

Lung morphology in the elderly: comparative CT study of subjects over 75 years old versus those under 55 years old.

PURPOSE: To describe thin-section pulmonary computed tomographic (CT) features in asymptomatic elderly individuals. MATERIALS AND METHODS: Institutional review board approval was given, and informed consent was obtained. Two study groups (older group, over 75 years of age; younger group, under 55 years) were prospectively identified from outpatient requests for CT of the abdomen or brain. Fifty-six consecutive volunteers (older group: n = 40, 18 men, 22 women; younger group: n = 16, eight men, eight women) with no known respiratory disease were included. Prone thin-section CT imaging was performed, and two observers independently scored images for the presence and extent of CT features (including reticular pattern, ground glass opacity, and thin-walled cystic air spaces). Group comparisons were made, and logistic regression analysis was used to assess relationships between CT findings and age and smoking history. RESULTS: A limited predominantly subpleural basal reticular pattern was identified in the majority (24 of 40, 60%) of individuals in the older group and was absent (zero of 16) in the younger group (P < .001). Cysts were seen in 10 (25%) of the 40 subjects in the older group but were seen in none of the subjects in the younger group (P = .02). Bronchial dilation and wall thickening were also seen significantly more frequently (P < .001) in the older group (24 [60%] and 22 [55%] of 40, respectively) than in the younger group (both one [6%] of 16). All findings were independent of pack-year smoking history with multiple logistic regression analysis. CONCLUSION: Thin-section CT findings usually associated with interstitial lung disease are frequently seen in asymptomatic elderly individuals and are absent in younger subjects. Therefore, these findings may not necessarily represent clinically relevant disease.

Adrenal phaeochromocytoma: correlation of MRI appearances with histology and function.

The purpose of this study was to describe the range of appearances of adrenal phaeochromocytomas on T2-weighted MRI, correlate appearances with histopathology, and quantify the incidence of the previously described hyperintense appearance. The appearance and MR characteristics of 44 phaeochromocytomas were reviewed retrospectively. T2-weighted appearances were grouped: (1) 'classical', homogeneous, high signal intensity, isointense to CSF; (2) homogeneous, isointense or minimally hyperintense to spleen, hypointense to CSF; (3) heterogeneous, marbled appearance; (4) heterogeneous, multiple high signal intensity pockets. All 44 adrenal phaeochromocytomas were well circumscribed, 1.2-15 cm in maximum diameter, with no visual or quantitative signal loss on chemical shift imaging. On T2-weighted MRI 5/44 (11%) had group 1 appearance; 15/44 (34%) group 2, 7/44 (16%) group 3; and 17/44 (39%) group 4. Homogeneous group 1 and 2 lesions were smaller (mean 4.5 cm) than heterogeneous group 3 and 4 lesions (mean 6.3 cm). Increasing MRI heterogeneity correlated pathologically with increasing amounts of haemorrhage, necrosis and fibrosis. No MRI features were predictive of malignancy. Non-functioning phaeochromocytomas were larger than functioning lesions. No size difference was seen between syndrome and sporadic lesions. In this large series we report a wide range of appearances of adrenal phaeochromocytomas on T2-weighted MRI. The previously described classical hyperintense phaeochromocytoma is relatively uncommon.

MRI demonstration of the effect of neoadjuvant radiotherapy on rectal carcinoma.

BACKGROUND AND PURPOSE: In patients with locally advanced rectal cancer, neoadjuvant long course (45-54 Gy in 25-30 fractions) chemoradiotherapy (CRT) may reduce tumour size and result in downstaging. In patients with primary resectable tumour short course (25 Gy in 5 fractions) radiotherapy (SCRT) reduces local recurrence but downstaging the disease or altering tumour size has not been described. We aimed to assess change in tumour size on MRI after SCRT or CRT. MATERIALS AND METHODS: Nineteen patients with rectal carcinoma underwent MRI before and after SCRT or CRT. In each case, tumour length and width were documented and number of locoregional lymph nodes recorded. Total mesorectal excision was performed in 15 patients and MR findings correlated with histopathology. RESULTS: Ten patients received SCRT and nine CRT. Tumour length reduced by 19% overall (15% following SCRT, 23% following CRT). Greater than 30% reduction (partial response) in maximum tumour thickness was seen in 4/10 (40%) following SCRT and 5/9 (56%) following CRT. CONCLUSIONS: Significant reduction in tumour size can be achieved with preoperative long course CRT and SCRT. This unexpected finding following SCRT has not been previously described.