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Dual-energy (DE) pulmonary blood volume (PBV) computed tomography (CT) has recently become available on clinical CT systems. The underlying physical principle of DECT is the fact that the photoelectric effect is strongly dependent on the CT energies resulting in different degrees of x-ray attenuation for different materials at different energy levels. DECT thus enables the characterization and quantification of iodine within tissues via imaging at different x-ray energies and analysis of attenuation differences. Technical approaches to DECT include dual-source scanners acquiring two scans with different energy levels simultaneously, and single-source CT scanners using sandwich detectors or rapid voltage switching. DE PBV CT enables the creation of iodine maps of the pulmonary parenchyma. Experience to date shows that these studies can provide additional physiological information in patients with acute or chronic pulmonary embolism beyond the pure morphological assessment a standard CT pulmonary angiography (CTPA) provides. It appears also to be promising for the evaluation of patients with obstructive airways disease. This article reviews the physics and technical aspects of DE PBV CT as well as the appearance of normal and abnormal lung tissue on these studies. Special consideration is given to pitfalls and artefacts.

OBJECTIVE. The purpose of this article is to review the role of imaging in the diagnosis, treatment, and follow-up of patients with sport-related flow limitations in the iliac arteries. CONCLUSION. Endurance athletes can develop flow restriction during exercise because of endofibrosis or kinking of the iliac arteries. Knowledge of this entity and the use of appropriate imaging techniques are crucial for diagnosis. Imaging plays an important role in the assessment of the underlying lesion and its location as well as in posttreatment follow-up.

Renal arteriovenous fistulas (AVFs) are rare abnormal communications between the arterial and venous circulations that can be congenital or acquired. We describe the multidetector computed tomography angiography (MDCTA) appearance of 2 cases of renal AVF, one with the cirsoid and one with the aneurysmal subtype, and the impact of these findings on therapeutic decision making and treatment follow-up.

Purpose The objective of this study is to define the role of three-dimensional (3D) rotational angiography (RA) in the evaluation of transplant hepatic arteries and compare it with digital subtraction angiography (DSA). Materials and methods The patency of the arteries and anastomoses, confidence in the ability to make a therapeutic decision, and the value of the study for the definition of the optimal projection for an intervention were graded on a scale from 0 to 10. Results Forty-three vascular segments in five patients were available for analysis. Complete concordance between 3D RA and DSA was present in 92.9% of the major (extrahepatic) segments. Three-dimensional RA demonstrated two major hepatic segments that were not visualized on DSA. There was no difference in diagnostic confidence, but 3D RA was considered superior for planning the optimal projection for intervention (10±0 vs. 6.4±1.8). Conclusion Three-dimensional RA DSA allows a more complete depiction of the hepatic allograft arterial system than DSA with comparable accuracy. Three-dimensional RA provides similar degrees of confidence in the ability to make a treatment decision, and its appropriate implementation could help reduce overall contrast and radiation dose.

Background Lower respiratory tract infection (LRTI) remains a leading cause of morbidity and mortality after solid organ transplantation (SOT). Patients and methods We performed a retrospective analysis of 217 episodes of LRTI in 143 SOT patients from a single center. Results There were 94 men and 49 women (85% Caucasian) of median age of 51 (range 17–79) years, including 50 renal, 86 liver, 6 pancreas, and 1 lung recipient. Forty patients experienced multiple episodes of LRTI. Median APACHE II score was 17 (range 5–40), median temperature was 38°C (range 35.3°C–40.2°C), and median white blood cell count was 12000 (range 100–106,000). Pneumonia developed at a median of 11 (range 2–191) days after the last surgical intervention. Of the 217 LRTIs, 163 were nosocomial infections (60 ventilator-associated). Overall crude mortality of 21% was increased in patients with multiple episodes of LRTI (25%) and after liver transplantation (33%). In 40 cases, treatment was initiated without identification of a specific pathogen. Overall, 202 microorganisms were found (41 mixed infections): Staphylococcus aureus (n = 32) of which 81% were MRSA; Escherichia coli (n = 9); Klebsiella spp (n = 7); Enterobacter spp (n = 11); Serratia spp (n = 12); Pseudomonas aeruginosa (n = 15); Stenotrophomonas maltophila (n = 15); Acinetobacter spp (n = 9); fungi (n = 18), and viruses (n = 17). Conclusion LRTI remains one of the most common, dangerous infections in transplant recipients with higher mortality than in other populations. MRSA is a particular problem. As a significant number of SOT patients develop multiple episodes of LRTI, a thorough reevaluation of the current guidelines for the treatment of pneumonia is urgently needed.

The objective of this study was to explore the role of three-dimensional (3-D) rotational angiography (RA) of the inferior vena cava (IVC; 3-D CV) before filter retrieval and its impact on treatment planning compared with standard anteroposterior cavography (sCV). Thirty patients underwent sCV and 3-D CV before IVC filter retrieval. Parameters assessed were: projection of filter arms or legs beyond the caval lumen, thrombus burden within the filter and IVC, and orientation of the filter within IVC. Skin and effective radiation doses were calculated. Statistical analysis was performed using paired Student t test and nonparametric McNemar’s test. Standard anteroposterior cavography detected 49 filter arms or legs projecting beyond the caval lumen in 25 patients. Three-dimensional CV demonstrated 89 filter arms or legs projecting beyond the caval lumen in 28 patients. Twenty-two patients had additional filter arms or legs projecting beyond the caval lumen detected on 3-D CV that were not detected on sCV (p < 0.001). Filter apex tilt detection differed significantly (p < 0.001) between sCV and 3-D CV, with 3-D CV being more accurate. The filter apex abutted the IVC wall in 10 patients (33%) on 3-D CV, but this was diagnosed in only 3 patients (10%) with sCV. Thrombus was detected in 8 patients (27%), 1 thrombus of which was seen only on 3-D CV, and treatment was changed in this patient because of thrombus size. Mean effective radiation doses for 3-D CV were approximately two times higher than for sCV (1.68 vs. 0.86 mSv), whereas skin doses were three times lower (12.87 vs. 35.86 mGy). Compared with sCV, performing 3-D CV before optional IVC filter retrieval has the potential to improve assessment of filter arms or legs projecting beyond the caval lumen, filter orientation, and thrombus burden.

Castleman's disease is a rare form of lymph node hyperplasia most commonly presenting as a solitary hypervascular mediastinal mass. Surgical resection is the treatment of choice, but this can be associated with significant blood loss due to its hypervascularity. We report two cases with a preoperative diagnosis of mediastinal Castleman's disease in whom preoperative embolization with Trisacryl gelatin microspheres (Biosphere Medical, Rockland, MA) was performed. Compared with the literature, a decrease in the amount of perioperative bleeding was noted in both cases.

Vascular malformations and tumors comprise a wide, heterogeneous spectrum of lesions that often represent a diagnostic and therapeutic challenge. Frequent use of an inaccurate nomenclature has led to considerable confusion. Since the treatment strategy depends on the type of vascular anomaly, correct diagnosis and classification are crucial. Magnetic resonance (MR) imaging is the most valuable modality for classification of vascular anomalies because it accurately demonstrates their extension and their anatomic relationship to adjacent structures. A comprehensive assessment of vascular anomalies requires functional analysis of the involved vessels. Dynamic time-resolved contrast material-enhanced MR angiography provides information about the hemodynamics of vascular anomalies and allows differentiation of high-flow and low-flow vascular malformations. Furthermore, MR imaging is useful in assessment of treatment success and establishment of a long-term management strategy. Radiologists should be familiar with the clinical and MR imaging features that aid in diagnosis of vascular anomalies and their proper classification. Furthermore, they should be familiar with MR imaging protocols optimized for evaluation of vascular anomalies and with their posttreatment appearances. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.315105213/-/DC1.

High spatial resolution magnetic resonance imaging (MRI) of patients with cystic adventitial disease can demonstrate connections between cysts in the adventitia and the adjacent joint, which is important for successful treatment. The inability to identify these during surgery can lead to a recurrence; thus, high spatial resolution MRI has the potential to affect therapy. This article presents the high spatial resolution MRI findings of cystic adventitial disease in a series of three consecutive patients and discusses the relevance of these findings to the etiology and therapy.

Renal artery stenosis is the most common surgical complication after renal transplantation. RT stenosis of the iliac artery presents in a similar way. Interventional techniques can salvage the graft in most cases.We report a renal transplant recipient who developed acute ischemic graft failure due to thrombosis of a previously stented iliac artery. He was successfully treated with mechanical thrombectomy and re-stenting. By this, we were able to salvage the graft with good long-term function.To the best of our knowledge this is the first case of restenting of an iliac artery in the setting of RT. Interventional radiology should be the approach in such cases.

A 24-year-old woman presented with severe bilateral buttock and lower extremity claudication that had developed over the course of 1 year. Prior to the onset of symptoms she was asymptomatic. Her medical history was remarkable for surgically repaired tetralogy of Fallot. Arm brachial indices were 0.57 on the right and 0.63 on the left. Doppler study showed monophasic waveforms at the thigh level bilaterally. Laboratory studies were positive for an elevated erythrocyte sedimentation rate (ESR) of 30 mm/h (normal 0–20 mm/h), but otherwise …

The authors report on a patient who underwent renal artery stent placement 6 hours after transplantation due to acute hypoperfusion of the transplant, which was diagnosed with intraoperative Doppler ultrasonography. Extensive atherosclerotic disease of the cadaveric transplant renal artery necessitated endarterectomy before creation of the anastomosis, and no further surgical options were considered feasible by the transplant surgeon. Six hours after the transplantation, percutaneous transluminal renal angioplasty and stent placement were performed, resulting in restoration of normal arterial flow and rescue of allograft function.

Background: A 47-year-old athletic man without relevant medical history consulted the vascular surgeon because of claudication in his left leg after 50 meters walking. There was no history of trauma and the clinical examination revealed coldness of the left foot. POPLITEAL ARTERY ENTRAPMENT SYNDROME R. Toorop, J. Poniewierski, J. Gielen, M. Maes, P. Van Schil, O. d’Archambeau Key-word: Arteries, extremities