Regressed testicular germ cell tumour in a post-pubertal male.

Testicular germ cell regression is a rare, generally metastatic phenomenon which describes the spontaneous, complete, or partial regression of a testicular germ cell tumour. As a result, studies have focused on defining specific histopathological criteria to establish if the resected testis is the primary source of the germ cell tumour. There are few publications which describe its presentation in the absence of distant metastases with elevated tumour markers and suspicious findings on testicular ultrasound. We present the clinical presentation and radiological features of a non-metastatic regressed testicular germ cell tumour following scrotal trauma in a post pubertal male.

High-Signal Bladder Urine at T1-Weighted MR Imaging Performed 1-7 Days After a Prior Gadolinium-Enhanced MRI: Prevalence and Correlation with Renal Function.

OBJECTIVE: To determine the prevalence of high-signal bladder urine at T1-weighted MRI performed 1-7 days after injection of gadolinium-based contrast material and to assess for correlation with altered renal function. METHODS: The study group consisted of 267 patients who underwent MRI that included the bladder 1-7 days after a prior gadolinium-enhanced MRI. A control group consisted of 200 patients who underwent pelvic MRI and had not received gadolinium-based contrast material within the prior month. One reader recorded the relative T1-weighted signal intensity of bladder urine and calculated the eGFR for each patient. A positive scan was defined as one with bladder urine T1-weighted signal higher than that of muscle. RESULTS: Twenty-five (9%) of 267 study group scans were positive; this included 68% (n=19) of scans obtained 12-24 hours after gadolinium-based contrast material administration, 21% (n=3) after 25-36 hours, 7% (n=2) after 37-48 hours, and 3% (n=1) after 49-72 hours. No positive scan occurred after 72 hours or in the control group. Mean eGFR in positive scans obtained more than 36 hours after gadolinium-based contrast material administration was significantly lower than in negative scans in the same timeframe (37 ml/min versus 76 ml/min, respectively; p = 0.01). CONCLUSION: High T1-weighted signal in bladder urine occasionally is present on MRI performed up to 3 days after gadolinium-based contrast material administration, presumably reflecting residual excreted gadolinium-based contrast material. When visible more than 36 hours after gadolinium-based contrast material administration, such increased signal is associated with decreased eGFR. ADVANCES IN KNOWLEDGE: Increased signal is occasionally present on bladder urine MRI performed up to 3 days post gadolinium-based contrast material administration. When higher signal is visible more than 36 hours after gadolinium-based contrast material administration it is associated with decreased eGFR.

Synovial chondroma in Hoffa's fat pad: Case report and literature review of a rare disorder.

INTRODUCTION: Synovial chrondomatosis is a rare disorder characterised by the development of hyaline cartilage from the synovial membrane. Large isolated lesions in the Hoffa's fat pad are an uncommon entity. PRESENTATION OF CASE: A 33 year old gentleman presented complaining of progressive knee pain associated with an enlarging lesion on the anterior aspect of the right knee, with associated locking and giving way. Examination revealed a firm 4×5cm lesion adjacent to the patellar tendon. Subsequent CT and MRI demonstrated a lesion in the inferior aspect of Hoffa's fat pad, with a second lesion adjacent to the proximal tibiofibular joint, in addition to advanced degenerative changes and a meniscal tear. He proceeded to excisional biopsy. Histological analysis was consistent with a solitary synovial osteochondroma. There were no atypical features suggestive of malignancy. DISCUSSION: Synovial chondromatosis is a rare disorder affecting the synovial joints. The underlying pathophysiology is thought to be metaplastic change of the synovium to hyaline cartilaginous tissue. Transformation to malignancy has been described but is uncommon with an estimated risk of 5%. It is 1.5-2 times as prevalent in males versus females. Symptoms which patients may complain of include pain;locking and giving way; and palpable masses. The management usually entails removal of the mass lesion with or without accompanying synovectomy. Recurrence of disease may occur in up to 15-23% of patients. CONCLUSION: Synovial chrondromatosis is a rare but well recognised condition. Long term follow up is advised in view of the risk of recurrence and malignant transformation.

Imaging appearances of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia.

OBJECTIVE: The objective of the study was to describe the imaging appearances of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) on computed tomography (CT). MATERIALS AND METHODS: Electronic medical records were searched for patients with pathology-proven DIPNECH who had a CT available for review. Eleven patients were included. RESULTS: The most common finding on CT was small pulmonary nodules which were present in all patients and were multiple (≥5) in 7/11 patients. Other CT findings included mosaic pattern attenuation and bronchial wall thickening/bronchiectasis. CONCLUSION: DIPNECH should be considered as a diagnostic possibility when multiple small pulmonary nodules are identified on CT, particularly if there is an associated carcinoid tumor.

"Superior cleft sign" as a marker of rectus abdominus/adductor longus tear in patients with suspected sportsman's hernia.

OBJECTIVE: We describe a new imaging sign, the "superior cleft sign", identified at both symphysography and MRI, which should be used as a marker of rectus abdominis/adductor longus attachment tearing. MATERIALS AND METHODS: A study population of 25 patients presenting with clinically suspected sportsman's hernia, who had undergone both symphysography and MRI of the groin were included for study. In each case, images were reviewed to determine the presence of a superior cleft, secondary cleft, and or both abnormalities. RESULTS: Images of all patients complaining of groin crease discomfort similar to sportsman's hernia revealed the presence of a superior cleft at the rectus abdominis/adductor longus attachment. This "superior cleft sign" correlated with the side of symptoms in each case, and, in contrast to the previously described secondary cleft along the inferior margin of the inferior pubic ramus, occurred parallel to the inferior margin of the superior pubic ramus. CONCLUSIONS: The presence of the "superior cleft sign" should be sought in addition to the previously described secondary cleft sign in sportspeople presenting with exercise-related groin pain or pubalgia. It should specifically be sought in patients referred with suspected sportsman's hernia.

Carotid plaque inflammation on 18F-fluorodeoxyglucose positron emission tomography predicts early stroke recurrence.

OBJECTIVE: Symptomatic carotid stenosis is associated with a 3-fold risk of early stroke recurrence compared to other stroke subtypes. Current carotid imaging techniques rely on estimating plaque-related lumen narrowing but do not evaluate intraplaque inflammation, a key mediator of plaque rupture and thromboembolism. Using combined (18) F-fluorodeoxyglucose positron-emission tomography (FDG-PET)/computed tomography, we investigated the relation between inflammation-related FDG uptake and stroke recurrence. METHODS: Consecutive patients with a recent (median, 6.5 days; interquartile range, 4-8) stroke, transient ischemic attack (TIA), or retinal embolism and ipsilateral carotid stenosis (≥50%) were included. FDG uptake was quantified as mean standardized uptake values (SUVs, g/ml). Patients were followed prospectively for stroke recurrence. RESULTS: Sixty patients were included (25 stroke, 29 TIA, 6 retinal embolism). Twenty-two percent (13 of 60) had stroke recurrence within 90 days. FDG uptake in ipsilateral carotid plaque was greater in patients with early recurrent stroke (mean SUV, 1.85 g/ml; standard deviation [SD], 0.44 vs 1.58 g/ml; SD, 0.32, p = 0.02). On life-table analysis, 90-day recurrence rates with mean SUV greater than a 2.14 g/ml threshold were 80% (95% confidence interval [CI], 41.8-99.2) versus 22.9% (95% CI, 12.3-40.3) with SUV ≤2.14 g/ml (log-rank, p < 0.0001). In a Cox regression model including age and degree of stenosis (50-69% or ≥70%), mean plaque FDG uptake was the only independent predictor of stroke recurrence (adjusted hazard ratio, 6.1; 95% CI, 1.3-28.8; p = 0.02). INTERPRETATION: In recently symptomatic carotid stenosis, inflammation-related FDG uptake was associated with early stroke recurrence, independent of the degree of stenosis. Plaque FDG-PET may identify patients at highest risk for stroke recurrence, who may be selected for immediate revascularization or intensive medical treatment.

Imaging of thoracic sarcomas of the chest wall, pleura, and lung.

Primary sarcomas of the thorax are uncommon. The purpose of this review is to describe the radiologic findings of sarcomas affecting the thorax, in particular the chest wall, pleura, and lungs. Most primary sarcomas affecting the thorax arise in the chest wall, and the most common sarcomas of the chest wall are chondrosarcoma, osteosarcoma, Ewing's sarcoma/primitive neuroectodermal tumor, malignant fibrous histiocytoma, and fibrosarcoma. Primary pleural and pulmonary sarcomas are rare. Although histologic analysis is almost always required for accurate diagnosis, imaging is important for staging of these tumors, and several of these tumors have distinctive radiologic features, allowing the radiologist to narrow the differential diagnosis.

Imaging of soft tissue and osseous sarcomas of the extremities.

Soft tissue and osseous sarcomas of the extremities are uncommon malignancies that represent very important diagnostic entities because of their aggressive nature. Radiologic investigations, including plain film, computed tomography, contrast-enhanced magnetic resonance imaging; scintigraphy, ultrasound, and positron emission tomography-computed tomography, play critical roles in providing a differential, establishing the diagnosis, demonstrating prognostic characteristics, and tailoring tumor treatment. The purpose of this review is to describe the most common soft tissue and osseous sarcomas of the extremities, with emphasis on their plain film and magnetic resonance imaging characteristics with the aim of aiding the reader to accurately describe the important imaging features and generate an appropriate differential diagnosis to aid the referring clinician with prompt appropriate management and treatment.

Whole-body magnetic resonance imaging in skeletal muscle disease.

The evaluation of muscle diseases has traditionally integrated clinical with biochemical findings, occasionally resorting to muscle biopsy. This article reviews the role and imaging appearances of muscle diseases at MRI, specifically emphasising the role of WBMRI in global assessment of muscle abnormality, and in particular its role in determining distribution and extent of muscle abnormality.

Targeted contrast agents--an adjunct to whole-body imaging: current concepts.

This article reviews the potential use of a combination of whole-body imaging and targeted contrast agents in improving diagnostics, with a particular focus on oncology imaging. It looks at the rationale for nanoparticles and their development as targeted contrast agents. It subsequently describes many of the advances made thus far in developing tissue-specific contrast agents capable of targeting tumors that combined with whole-body imaging may enable superior cancer detection and characterization.

Molecular and magnetic resonance imaging: The value of immunoliposomes.

Molecular imaging has the potential to transform the field of diagnostic imaging through enabling far more detailed investigation and characterisation of disease processes than is currently possible. Magnetic resonance imaging (MRI) is capable of three-dimensional non-invasive imaging of opaque tissues at near cellular resolution. Among the imaging techniques available today, MRI has, perhaps, the greatest potential to exploit the possibilities that molecular imaging presents. Nanoparticles are the focus of intense research, due to a wide variety of potential applications in the biomedical, optical, and electronic fields. In this article we examine the progress made in the development of nanoparticles as targeted contrast agents for molecular magnetic resonance imaging. In particular, we will examine the potential of antibody-targeted liposomes (immunoliposomes) as vehicles for delivering MRI contrast agents to cellular biomarkers, thus enabling visualisation of structures and processes at the molecular level. We will address some of the challenges that must be faced by researchers in this field before the progress made in the laboratory can be translated into improved clinical diagnostics and therapeutics.

Experiencia norteamericana

Trata los temas de la privatización y regulación de los servicios de agua y saneamiento desde la perspectiva y experiencia de los Estados Unidos. En particular, describe la regulación tal como la practican las comisiones reguladoras de servicios públicos de los estados y transmite algunas de las lecciones que aprendieron con esa forma de regulación. Concluye que con respecto a los servicios de agua potable y desagues cloacales, en los Estados Unidos estas industrias están avanzando hacia una participación mucho mayor del setor privado, aunque quizás no tan rápido como en Argentina