The value of MR angiography in predicting the risk of torsion of a pelvic spleen during pregnancy

A case of an enlarged pelvic spleen, studied with MRI and MR angiography (MRA), is presented in a 32-year-old female wishing to become pregnant. An ectopic located spleen may be complicated by an acute abdomen due to torsion of the splenic vascular pedicle, resulting in splenic infarction. Displacement of the spleen and splenic pedicle during pregnancy may further increase the risk of torsion. Urgent splenectomy during pregnancy is associated with a high fetal and maternal mortality and morbidity. On the other hand, elective splenectomy of a pelvic spleen before pregnancy can result in adhesion formation, compromising the patient's fertility. The abilities of MRI and MRA in predicting the risk of these life-threatening complications during pregnancy are discussed, in order to evaluate the benefit-risk ratio of surgical treatment by splenectomy of splenopexia.     

Real-time contrast-enhanced ultrasound of the spleen: examination technique and preliminary clinical experience

PURPOSE: To report our preliminary experience in the evaluation of the spleen using a real-time contrast-specific ultrasound module in combination with a second-generation contrast agent. MATERIALS AND METHODS: In a 7-month period, 55 patients (34 males and 21 females, aged 5-77 years) with spleen disorders were evaluated by means of contrast-enhanced ultrasound. Two patients were studied because of baseline evidence of an accessory spleen and both underwent ultrasound follow-up. Twenty-five patients were studied for abdominal trauma and results were correlated with those of helical CT. Three patients were examined for suspected splenic infarction and for all CT correlation was obtained. Finally, twenty-five subjects were examined for focal diseases, such as lymphomas (17 cases) and focal lesions (8 cases); contrast-enhanced US results were correlated with those of CT (8 cases), MRI (2 cases), ultrasound follow-up (8 cases), biopsy (2 cases) or splenectomy (1 case). After an initial baseline study, the contrast-enhanced examinations were carried out using a dedicated unit equipped with a continuous contrast-specific module at low acoustic pressure. The examination started immediately after rapid contrast injection and lasted approximately 4 minutes. In the comparison between baseline and contrast-enhanced ultrasound, the following aspects were considered: detection rate of parenchymal changes, lesion extent (equal to CT, under- or overestimated), and lesion conspicuity (lesion-to-parenchyma gradient, from 0 = absent to 3 = high). RESULTS: In the 2 patients with accessory spleen, an enhancement very similar to that of the adjacent parenchyma was present and a small vascular pedicle was noted. Among the trauma patients, 18 had a direct splenic injury and one showed splenic contraction and hypoperfusion due to shock. In 74% of cases, a peritoneal effusion was demonstrated both with baseline and contrast-enhanced ultrasound; perisplenic blood collections (58% of cases) were identified in 42% of patients by both baseline and contrast-enhanced ultrasound; post-traumatic infarction was always revealed by contrast-enhanced ultrasound (11% of cases) but never by baseline ultrasound; parenchymal injuries were detected with a sensitivity of 63% by baseline ultrasound and a sensitivity of 89% by contrast-enhanced ultrasound. Moreover, contrast-enhanced ultrasound revealed findings undetectable on conventional ultrasound: global splenic hypoperfusion in 2 cases (due to shock in one and pedicle avulsion in the other), intraparenchymal contrast collections in 21% of positive cases (as confirmed by CT), extrasplenic contrast leakage in 1 of 2 cases demonstrated by CT. Of the 3 cases of splenic infarction, baseline sonography only only identified two, whereas the contrast-enhanced examination clearly identified three. Contrast-enhanced ultrasound revealed 35 of 39 focal lesions in patients studied for Hodgkin's disease and splenic focal lesions. Baseline ultrasound had a lower sensitivity (23 lesions). Lesion extension shown by contrast-enhanced sonography was equivalent to that provided by standard methods in 88% of cases (underestimated in 9% and overestimated in 3%); baseline US correctly estimated lesion size in 52% of cases, under- and overestimating them in 35% and 13% of cases, respectively. Lesion conspicuity was graded as 1 (low) in 16%, 2 (moderate) in 67%, and 3 (high) in 17% of the cases identified by enhanced sonography. Baseline ultrasound was less effective: conspicuity was graded as 1 in 42%, 2 in 39%, and 3 in 19% of cases. CONCLUSIONS: The spleen is the ideal organ to be studied with second-generation contrast media due to its superficial location, high vascularity, small size and homogeneous texture. Contrast-enhanced ultrasound is a simple, poorly-invasive and accurate tool for the evaluation of splenic disorders. If our data are confirmed, it will be possible to reduce the use of more complex technologies such as CT and MRI.     

CT of blunt abdominal and pelvic vascular injury

Computed tomography (CT) has been shown to be increasingly useful in the evaluation of blunt trauma patients with suspected abdominopelvic vascular injuries. CT findings of abdominopelvic vascular insult may be broadly characterized as end-organ abnormalities or direct evidence of vascular injury. End-organ abnormalities implying an underlying vascular insult include identifying an area of relative hypoperfusion in solid organ injury. Direct evidence of a vascular injury includes identifying an irregular or thrombosed vessel or an area of active hemorrhage, among other findings. This review article aims to review and illustrate these findings of blunt abdominopelvic vascular trauma. Also, evolving lessons from our level I trauma center in the use of multiphasic imaging to further characterize sources of a vascular blush and the differentiation of arterial from venous sources of active hemorrhage are discussed.     

Nonsurgical management of blunt splenic injury: use of CT criteria to select patients for splenic arteriography and potential endovascular therapy

PURPOSE: To determine if contrast material-enhanced spiral computed tomography (CT) can be used to select patients with blunt splenic injuries to undergo arteriographic embolization. MATERIALS AND METHODS: During a 15-month period, 78 patients who were hemodynamically stable and required no immediate surgery underwent contrast-enhanced spiral CT followed by splenic arteriography. CT scans were assessed for splenic vascular contrast material extravasation or posttraumatic splenic vascular lesions. Medical records were reviewed for splenic arteriographic results and clinical outcome. RESULTS: There were 25 grade I, 12 grade II, 27 grade III, 12 grade IV, and two grade V splenic injuries. CT showed active contrast material extravasation in seven patients and splenic vascular lesions in 19 patients. At CT, splenic vascular contrast material extravasation was 100% (seven of seven patients) and a posttraumatic splenic vascular lesion was 83% (10 of 12 patients) sensitive on the basis of arteriographic or surgical outcome in predicting the need for transcatheter embolization or splenic surgery. Overall, CT had a sensitivity of 81% (17 of 21 patients), a specificity of 84% (48 of 57 patients), negative and positive predictive values of 92% (48 of 52 patients) and 65% (17 of 26 patients), respectively, and an accuracy of 83% (65 of 78 patients) in predicting the need for splenic injury treatment. CONCLUSION: Contrast-enhanced spiral CT plays a valuable role in selecting hemodynamically stable patients with splenic vascular injury who may be treated with transcatheter therapy and potentially improves the success rate of nonsurgical management.     

Cortical cerebral blood flow in HIV-1-related dementia complex

Dementia complex is a syndrome that affects a high percentage of AIDS patients. Neuroradiological findings may be non-specific and the diagnosis can be difficult in its earlier stages. Preliminary radionuclide studies have recently reported derangements of regional cerebral blood flow (CBF) which may be present before overt anatomical injury. This study reports on cortical and cerebellar CBF changes in 26 patients studied with 99Tcm-HM-PAO and single photon emission computed tomography (SPECT). Extensive cortical CBF derangements were observed in all patients and an evident cerebellar hypoperfusion was also present in three. The prevalence of hypoperfusion was highest in the frontal and parietal lobes. The extension of the hypoperfusion showed a highly significant correlation with the severity of the dementia complex (P less than 0.01 by chi 2 test). The SPECT also showed hypoperfused areas in three patients with normal CT scans and in two patients with normal MRI scans. These results confirm previous preliminary reports on the high prevalence of cortical hypoperfusion in dementia complex and suggest the use of this radionuclide technique to assist in the early diagnosis and follow-up of AIDS patients, especially when CT and MRI are still normal.     

Pedicle injury masquerading as renal contusion: A possible urographic pitfall

Renal vascular pedicle injuries are relatively rare, accounting for 1–5% of renal injuries [1]. Intravenous urography is generally the initial procedure used to assess the severity of renal damage and the need for further evaluation. Non-function of the injured kidney is a characteristic finding of renal pedicle injury on excretory urography [1, 2, 3, 4]. This finding generally necessitates further expeditious evaluation with renal arteriography. Opacification of the pelvi-ureteric system during excretory urography generally implies that the renal vascular pedicle is intact and a major renal injury does not exist. We report a case of a major renal vascular injury associated with excretion of contrast at urography—findings mimicking the radiographic features of renal contusion.     

Optimizing multidetector CT for visualization of splenic vascular injury. Validation by splenic arteriography in blunt abdominal trauma patients

Nonoperative management of blunt splenic injury is the treatment of choice in hemodynamically stable patients. Detection of vascular injury by multidetector CT (MDCT) is the most significant factor predicting the need for endovascular treatment. This study evaluated the timing of the appearance of vascular lesions during angiography. Images from 20 patients embolized for pseudoaneurysms (PSA) were evaluated. Angiograms were reviewed for phase and timing of PSA. Admission MDCT was reviewed for injury grade and PSA. Initial MDCT evaluation indicated grade III and IV splenic injuries in 9 and 11 patients, respectively. PSA was seen on MDCT in 14/20 (70%) patients. Time from opacification of the aorta to vascular injury was 1.32 s for arterial phase injuries compared with 2.05 s for postcapillary injuries (P = 0.097). Angiography demonstrated 15 vascular injuries during the arterial and 5 in the venous phase. Of injuries seen during arterial phase angiography, 10/15 (66%) were identified on MDCT. Of the five injuries that exhibited postcapillary-phase findings, 4/5 (80%) demonstrated PSA (P = 0.5). Vascular lesions are a better indicator of subsequent clinical deterioration than splenic injury grade. PSAs are more frequently seen in postcapillary vascular injuries than arterial phase lesions with the current timing of MDCT. In a subset of patients in whom splenic injury grades III and IV warrant angiography, PSAs are not initially demonstrated on MDCT. Therefore, alteration of MDCT timing parameters to better correlate with arterial phase angiography may improve initial diagnosis of vascular injury.     

Torsion of a wandering spleen: CT appearance

A case of wandering spleen with torsion of the splenic vascular pedicle and pancreatic tail is presented. The entity was diagnosed and evaluated preoperatively with various imaging modalities (ultrasound, nuclear medicine, and CT) as well as visceral angiography.     

Capillary hemangioma of the spleen on conventional and contrast-enhanced US

We report a case of splenic vascular neoplasm in a 75 year old asymptomatic woman. CT and enhanced sonography were not consistent with a typical hemangioma. Splenectomy was finally realised and pathologic exam showed a capillary hemangioma with thrombosis. The imaging appearance of splenic hemangiomas may be complex because of splenic topography, size and complicating features. The differentiation of these lesions from malignant disease may not be possible.     

Splenic Artery Syndrome After Orthotopic Liver Transplantation: Treatment With the Amplatzer Vascular Plug

Purpose  

To evaluate the safety and efficacy of the Amplatzer vascular plug (AVP) for embolization of the splenic artery in patients with hepatic hypoperfusion after orthotopic liver transplantation (OLT).     

Traumatic injuries: imaging and intervention in post-traumatic complications (delayed intervention)

The nonoperative management (NOM) of abdominal trauma has gained increasing acceptance over the past decade. This approach has been extended to severe trauma patients previously considered as candidates for surgery. Consequently, the incidence of delayed and uncommonly encountered complications has increased. Causes of delayed complications are multiple and include: (a) abnormal or insufficient injury healing process; (b) retention of necrotic tissue; (c) secondary infection of initially sterile collections; and (d) underestimation of injury severity. The purpose of this review article is to explain the role of various imaging modalities in detecting post-traumatic delayed complications and to highlight the usefulness of minimally invasive techniques, including laparoscopy, biliary endoscopy, therapeutic angiography and image-guided drainage. Subsequent complications, which do not necessarily negatively influence the final outcome, are often predictable, virtually obligatory consequences of the successful NOM of high-grade or complex abdominal injuries. Between 50 and 60% of those patients with grade-IV or grade-V liver or splenic lacerations require some type of interventional treatment; therefore, indiscriminate discharge of patients with solid organ injury managed conservatively may be potentially harmful. As the incidence of complications is higher for more severe grade-IV or grade-V liver, spleen, or kidney injuries, scheduled follow-up CT scans may be rational in this subset of patients to identify potential complications amenable to early application of interventional techniques. Follow-up CT scans are unnecessary in stable adults or children with low-grade injury. Delayed splenic or hepatic rupture is one of the major concerns because this type of complication remains difficult to predict and historically often requires emergent surgery. These ruptures may benefit from NOM, should the same criteria as for primary rupture be respected. Conversely, parenchymatous focal pooling of contrast on initial CT is a good predictor for the development of delayed vascular malformation. In children, as a large part of splenic and hepatic vascular malformations resolve spontaneously, expectant observation may be indicated provided that a strict imaging follow-up is performed until complete disappearance of these lesions. If needed, embolization of parenchymal vascular lesions should be performed as selectively as possible in order to avoid functional parenchyma loss and to reduce the risk of secondary infection of hematoma or ischemic tissue. Technical improvements, such as microcatheter systems and direct percutaneous approach to targeted lesions, have widened the potential for safe endovascular management of acquired vascular malformations. Advantages and disadvantages relative to the different embolic agents are explained. Endoscopic retrograde pancreatography is the chief investigational tool for detecting biliary and pancreatic ducts injuries. The respective roles of endoscopic, percutaneous and surgical approaches in the management of these complications are discussed. The CT scan and ultrasound-guided drainage provide effective nonoperative options in the management of post-traumatic parenchymatous and (retro)-peritoneal collections. Treatment modalities of less common complications, such as bowel stricture or perforation, mesenteric vascular injuries and renal trauma-induced hypertension, are reviewed.     

脾脏占位性病变的CT诊断

探讨ＣＴ对脾脏占位性病变（ＳＳＯＬ）的诊断及鉴别诊断价值。材料和方法：收集５０例脾脏病变（包括恶性、肿瘤２１例,良性肿瘤１１例,结核１１例,脓肿２例,囊肿５例）的ＣＴ资料,分析脾脏大小、病灶数目、密度、边界、强化程度等表现。结果：脾脏恶性肿瘤多表现为单发或多发低密度灶,边界不清,增强后无强化或轻度不均匀强化,脾脏肿大显著,常伴淋巴结肿大。良性肿瘤多表现为边界清、密度均匀低密度灶,脾脏不大或轻度增大     

Intense contrast enhancement of the adrenal glands: another abdominal CT finding associated with hypoperfusion complex in children.

OBJECTIVE: A constellation of CT findings has been associated with posttraumatic shock in children. Findings include fluid-filled, dilated bowel; intense enhancement of bowel wall, mesentery, pancreas, kidneys, aorta, and inferior vena cava; and small caliber of aorta and inferior vena cava. The objective of this study is to describe an additional CT finding in the hypoperfusion complex: symmetric, intense contrast enhancement of the adrenal glands. CONCLUSION: Intense enhancement (as great as that of adjacent vascular structures) of normal-shaped adrenal glands occurs in association with hemodynamic instability in children. The presence of intense adrenal enhancement may provide additional evidence of hemodynamic instability and help differentiate it from direct bowel injury.     

Posterior reversible encephalopathy syndrome, part 2: controversies surrounding pathophysiology of vasogenic edema

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state accompanied by a unique brain imaging pattern typically associated with a number of complex clinical conditions including: preeclampsia/eclampsia, allogeneic bone marrow transplantation, solid organ transplantation, autoimmune diseases and high dose cancer chemotherapy. The mechanism behind the developing vasogenic edema and CT or MR imaging appearance of PRES is not known. Two theories have historically been proposed: 1) Severe hypertension leads to failed auto-regulation, subsequent hyperperfusion, with endothelial injury/vasogenic edema and; 2) vasoconstriction and hypoperfusion leads to brain ischemia and subsequent vasogenic edema. The strengths/weaknesses of these hypotheses are reviewed in a translational fashion including supporting evidence and current available imaging/clinical data related to the conditions that develop PRES. While the hypertension/hyperperfusion theory has been most popular, the conditions associated with PRES have a similar immune challenge present and develop a similar state of T-cell/endothelial cell activation that may be the basis of leukocyte trafficking and systemic/cerebral vasoconstriction. These systemic features along with current vascular and perfusion imaging features in PRES appear to render strong support for the older theory of vasoconstriction coupled with hypoperfusion as the mechanism.     

CT diagnosis of renal pedicle injury

The CT findings in 6 renal vascular injuries were reviewed. The most specific observations in traumatic renal arterial thrombosis were nonexcretion, "rim" enhancement, and abrupt termination of an enhanced renal artery. Other signs of a disrupted renal vascular pedicle included central retroperitoneal hematoma associated with limited perinephric hematoma causing lateral displacement of the kidney. We conclude that CT allows differentiation of the causes of the absent or poor urographic nephrogram after trauma and may obviate the need for time-consuming angiography. CT should replace excretory urography for the evaluation of polytrauma, especially when the mechanism of injury is compatible with pedicle disruption.     

CT diagnosis of renal pedicle injury

The CT findings in 6 renal vascular injuries were reviewed. The most specific observations in traumatic renal arterial thrombosis were nonexcretion, “rim” enhancement, and abrupt termination of an enhanced renal artery. Other signs of a disrupted renal vascular pedicle included central retroperitoneal hematoma associated with limited perinephric hematoma causing lateral displacement of the kidney. We conclude that Ct allows differentiation of the causes of the absent or poor urographic nephrogram after trauma and may obviate the need for time-consuming angiography. Ct should replace excretory urography for the evaluation of polytrauma, especially when the mechanism of injury is compatible with pedicle disruption.     

The forgotten organ: contrast enhanced sonography of the spleen

OBJECTIVE: Ultrasound contrast agents in conjunction with contrast specific imaging techniques, are increasingly accepted in clinical use for diagnostic imaging in several organs. Contrast enhanced sonography (CES) of second-generation contrast media have shown a spleen-specific uptake of the microbubble contrast agent. The aim of this review is to illustrate indications for the use of CES in patients with suspected (peri-)splenic pathology. METHODS: This review based on the experience of transcutaneous CES in 200 patients with (peri-)splenic pathology diagnosed by B-mode sonography at an internal medicine center. CES studies were performed with a contrast-devoted unit (Acuson, Sequoia, Siemens medical solution) that had contrast-specific, continuous-mode software. A low mechanical index was used. A sulfur hexafluoride-based microbubble contrast medium (Sonovue, Bracco SpA, Milan, Italy) was injected. RESULTS: On our experience, there are several clinical conditions which may show an diagnostic advantage of CES in comparison to B-mode US. CES should be performed to investigate: (1) the perisplenic tumor to diagnose or exclude accessory spleen, (2) the small-sized spleen to diagnose functional asplenia/hyposplenia, (3) the inhomogenous spleen of unknown cause to diagnose focal lesions within the spleen, (4) the incidentally found hypoechoic splenic tumor to diagnose high vascular splenic hemangioma, (5) focal lesions suspect for splenic abscess, hematoma, infarction to confirme diagnosis, and (6) patients with abdominal trauma to diagnose or exclude splenic injury. CONCLUSION: CES is of diagnostic value in several clinical circumstances to diagnose accessory spleen, functional asplenia, small-sized splenic involvement, high vascular splenic hemangioma, and vascular splenic pathology like splenic infarction, splenic abscess, and splenic laceration.     

Blunt splenic trauma: delayed-phase CT for differentiation of active hemorrhage from contained vascular injury in patients

PURPOSE: To retrospectively evaluate delayed-phase computed tomography (CT) in the differentiation of active splenic hemorrhage requiring emergent treatment from contained vascular injuries (pseudoaneurysms or arteriovenous fistulas) that can be treated electively or managed conservatively. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant retrospective study; the informed consent requirement was waived. Forty-seven patients with blunt splenic injury diagnosed at CT after blunt abdominal trauma were evaluated. Abdominal and pelvic dual-phase CT was performed; images were obtained 60-70 seconds and 5 minutes after contrast material injection. Scans were reviewed in consensus by two radiologists. Splenic injuries were graded with the American Association for the Surgery of Trauma Splenic Injury Scale. Patients with intrasplenic hyperattenuating foci on portal venous phase images were classified as having active splenic hemorrhage (group 1) or a contained vascular injury (group 2) on the basis of delayed-phase imaging findings. Findings suggestive of active hemorrhage included areas that remained hyperattenuating or increased in size on delayed-phase images. The clinical outcome of these patients was determined by reviewing their medical records. Relationships between several factors were tested with the Fisher exact test, including (a) the presence or absence of hyperattenuating foci and management and (b) the presence of contained vascular injury or active extravasation and management. RESULTS: Portal venous phase CT revealed a focal high-attenuation parenchymal contrast material collection in 19 patients: nine patients were classified as group 1 and 10 were classified as group 2. All patients in group 1 underwent emergent splenectomy, and all patients in group 2 were initially treated without surgery. Significant differences in management were noted on the basis of whether hyperattenuating foci were seen on portal venous phase images (P < .001) and whether hyperattenuating foci seen at portal venous phase imaging were further characterized as active splenic hemorrhage or a contained vascular injury at delayed-phase CT (P < .001). CONCLUSION: In blunt splenic injury, delayed-phase CT helps differentiate patients with active splenic hemorrhage from those with contained vascular injuries.     

慢性脑供血不足（CCCI）的脑血流灌注成像研究进展

脑血流灌注不足是CCCI的主要病理生理机制。目前用于评价脑血流量的方法有CT灌注成像（CTPI）、磁共振灌注加权成像（PWI）、正电子发射性体层显像（PET）、单光子发射性体层扫描（SPECT）、氙气CT-灌注成像（Xe-CT）等。利用CT、MRI等影像学技术可显示CCCI低灌注损伤的范围和程度,早期发现脑缺血,有效避免脑梗死、血管性痴呆的发生。     

Nontraumatic splenic emergencies: cross-sectional imaging findings and triage

The spleen is commonly involved in a wide spectrum of hematologic, immunologic, neoplastic, infectious, and vascular systemic disorders. Sometimes overlooked on imaging studies outside the trauma setting, the spleen may harbor severe infections, and occasionally undergoes spontaneous bleeding or rupture. This pictorial essay reviews common and unusual causes of nontraumatic acute abnormalities primarily involving the spleen, and their cross-sectional imaging appearances. Emphasis is placed on multidetector computed tomography (MDCT) imaging, which represents the modality of choice to comprehensively assess acute splenic disorders including partial or complete infarctions, vascular diseases such as venous thrombosis, abscess collections, bleeding, and rupture. State-of-the-art magnetic resonance imaging represents a problem-solving technique. Borrowing from experience with grading abdominal trauma according to the traditional American Association for the Surgery of Trauma scale, spontaneous splenic injuries are confidently detected and characterized at MDCT. Furthermore, MDCT allows to identify or exclude coexistent perisplenic and intraperitoneal hemorrhage, presence and source of active bleeding, and contained vascular injury. Occasionally idiopathic, spontaneous splenic injuries should be suspected when acute abdominal manifestations and signs of hemodynamic compromise occur in a background of acute viral infections, endocarditis or sepsis, malaria, immune suppression, hematological disorders, malignancies, coagulopathy, or therapeutic anticoagulation. These uncommon yet life-threatening conditions require prompt diagnostic evaluation that allows correct triage between conservative, medical, interventional, and surgical treatment, and may obviate splenectomy. Finally, MDCT imaging allows differentiation of splenic rupture from other rare causes of spontaneous hemoperitoneum, and reliable follow-up of nonsurgically treated patients.