Splenic abnormalities: a comparative review of ultrasound, microbubble-enhanced ultrasound and computed tomography

Contrast-enhanced Ultrasound as a Method of Splenic Injury Assessment

Splenic injuries are common in abdominal trauma, as the spleen is one of the most often harmed organs. The treatment of splenic injuries underwent major changes during the past decades, shifting from a surgical approach to nonoperative management. This change of the proceedings results from a constantly growing awareness of the spleen's crucial hematological and immunological function and was possible owing to the advances in radiological techniques. In a setting of high-energy trauma in hemodynamically stable patients, computed tomography (CT) remains the gold standard. Where ultrasonography (US) is of major importance is in cases of unstable patients undergone high-energy trauma or in patients after low-energy trauma. Nevertheless, baseline US's sensitivity is not sufficient to detect splenic traumatic injuries; hence, a new method was developed involving ultrasound contrast agents (UCAs), called contrast-enhanced ultrasound (CEUS). In a low-energy trauma setting, it facilitates the diagnosis of abdominal lesions with a sensitivity close to that of CT, without the disadvantages of the latter. In addition, CEUS can be used in the follow-up of abdominal traumatic injuries. The fact that CEUS preserves CT's sensitivity while not carrying the risk of radiation-induced cancer makes it feasible for children and pregnant women. This review aims to discuss the technical aspects of CEUS, the limitations, and possibilities regarding this modality, present the appearance of both a healthy and injured spleen, and compare CEUS's effectiveness to that of CT through an analysis of retrievable studies.

Splenic Embolism in Infective Endocarditis: A Systematic Review of the Literature with an Emphasis on Radiological and Histopathological Diagnoses

Infective endocarditis (IE) is characterised by fever, heart murmurs, and emboli. Splenic emboli are frequent in left-sided IE. A systematic review of the literature published on splenic embolism (SE) between 2000 and 2023 was conducted. Search strategies in electronic databases identified 2751 studies published between 1 January 2000 and 4 October 2023, of which 29 were finally included. The results showed that the imaging tests predominantly used to detect embolisms were computed tomography (CT), magnetic resonance imaging, positron emission tomography (PET)/CT, single-photon emission computed tomography/CT, ultrasound, and contrast-enhanced ultrasound. More recent studies typically used 18F-FDG PET-CT. The proportion of SE ranged from 1.4% to 71.7%. Only seven studies performed systematic conventional CT screening for intra-abdominal emboli, and the weighted mean frequency of SE was 22% (range: 8-34.8%). 18F-FDG PET-CT was performed systematically in seven studies, and splenic uptake was found in a weighted mean of 4.5%. There was a lack of uniformity in the published literature regarding the frequency and management of splenic embolisation. CT scans were the most frequently used method, until recently, when 18F-FDG PET-CT scans began to predominate. More data are necessary regarding the frequency of SE, especially focusing on their impact on IE management and prognosis.

[Diagnostics and treatment of splenic abscesses]

A splenic abscess is a rare disease found in less than 1% of all autopsy studies. Several different diseases are associated as a predisposing factor, such as septic bacteremia due to endocarditis or diverticulitis, previous splenic trauma, immunosuppressive medication or diseases. The reported mortality in the literature is up to 24.5% in correctly diagnosed and treated cases. The diagnostic work-up primarily comprises sonography and computed tomography as well as a percutaneous puncture for determination of the pathogen. In most cases, a percutaneous interventional drainage treatment is sufficient and a splenectomy is necessary only in refractory cases.

Three-dimensional morphological analysis of the human spleen and its surrounding organs during the early fetal period

The spleen has variations in its morphology and is considered to acquire a defined shape in the third month of gestation. However, few studies have investigated spleen development during the first 3 months of fetal life. This study aimed to determine the three-dimensional (3D) morphogenesis of the spleen during the third month of gestation. In this study, 30 fetal specimens (crown-rump length [CRL]: 22-103 mm) were subjected to magnetic resonance imaging analysis. We manually segmented the spleen, stomach, and adrenal gland, reconstructed 3D models, and analyzed the volume and shape of these organs. The results showed that the variation in spleen size was large compared to that in other organs. Spleen morphology was classified into six types based on the number of splenic surfaces as follows: two-faced, three-faced, four-faced, five-faced, ovoid, and irregular. Two-faced spleens were only observed in small specimens, whereas three- and four-faced spleens were observed in larger specimens. We also revealed that the number of fetal splenic surfaces increased as CRL enlarged. Additionally, 3D models indicated that some specimens formed their splenic surfaces without contact with the adjacent organs. This suggested that the splenic surface may be caused not only by pressure from the faced organs but also by an intrinsic program. This study may provide a better understanding of the normal development of the spleen during the early fetal period, and may potentially assist future studies in investigating congenital morphological anomalies of the spleen.

Applications of Contrast-Enhanced Ultrasound in Splenic Studies of Dogs and Cats

Simple Summary

Contrast-enhanced ultrasound (CEUS) is a noninvasive imaging technique that has become a reliable tool for identifying and monitoring lesions in both human and animals. In the last decade, its use in veterinary diagnostic imaging has gained increasing importance, and it can be reliable in everyday clinical practice. However, there is a lack of reviews describing existing CEUS results in the study of splenic lesions, which is of particular importance in dogs and cats. This information is important for validating its efficacy, to facilitate decision making related to sampling procedures and diagnosis, or even as a means to select CEUS as an alternative diagnostic tool in specific cases. Our goal was to review the existing studies of CEUS applications for splenic ultrasound studies in cats and dogs, present these results in a systematic manner, and combine this information into practical guidelines that can be used to help diagnosis and interpretation in both clinical cases and research.

Abstract

Contrast-enhanced ultrasound (CEUS) is an emerging technology in veterinary medicine involving the administration of intravenous contrast agents, and it is increasingly recognized for its high potential as a diagnostic imaging tool for small animals. This exam is easy and quick to perform, safe and reliable, and allows for the differentiation of lesions. It permits the identification of lesions that may require more invasive procedures, from those that can be safely dismissed to those that can be followed-up with ultrasound imaging. Although it has been extensively reviewed for use in human medicine, there is an overall lack of information about the application of this technique for cats and dogs, particularly in splenic studies, which can be particularly important for small animals. The present review describes and summarizes the CEUS applications used for splenic analysis in cats and dogs, providing a basic overview of CEUS technology with examples of common and uncommon features of focal splenic lesions. It also systematically gathers the results obtained for benign and malignant splenic lesions described in the literature, whilst providing guidelines for their interpretation. Furthermore, it presents the advantages of using CEUS for splenic analysis in cats and dogs and the main factors that may influence the quality of the imaging and the accuracy of the diagnosis. This type of knowledge can be used to provide a framework to help veterinarians make informed decisions regarding the use of this emerging technique for splenic lesions, guiding their interpretation of CEUS findings in the splenic ultrasounds of cats and dogs.

Ultrasonographic atlas of splenic lesions

Ultrasonography (US) is widely used for abdominal imaging. Its noninvasiveness, extensive range of application, and low cost make US a useful and valuable tool for the detection, diagnosis, and follow-up of splenic abnormalities. Concomitantly with the increasing frequency of imaging, more splenic lesions are being discovered and the requirements for the differential diagnosis are rising. In this pictorial essay, we introduce the representative US findings of many different splenic lesions, including normal sonographic findings, normal variants and congenital anomalies, infectious conditions, benign and malignant neoplasms, and non-neoplastic lesions. Knowledge of the US features of various splenic lesions will help narrow the differential diagnosis and guide clinical decision-making.

Identification of secondary splenic lymphoma with contrast-enhanced ultrasound in the pediatric population. A case report

Contrast-enhanced ultrasound scan (CEUS) is the application of ultrasound contrast agents (UCAs) to traditional ultrasound. Our aim is to report the use of CEUS for a prompt assessment of a suspected secondary splenic lymphoma in a child, which, in our experience, has allowed an accurate description of the parenchymal perfusion and vascularization pattern, leading to a confident diagnosis. We suggest that CEUS will replace Magnetic resonance imaging (MRI) or Computed tomography (CT) as standard imaging option for differential diagnosis of spleen lesions in pediatric population. As a result this will lead to decreasing the overall use of ionizing radiation and reducing the time interval to a certain diagnosis.

Contrast-enhanced ultrasound of the spleen, pancreas and gallbladder in children

Gray-scale and color/power Doppler ultrasound (US) are the first-line imaging modalities to evaluate the spleen, gallbladder and pancreas in children. The increasing use of contrast-enhanced ultrasound (CEUS) as a reliable and safe method to evaluate liver lesions in the pediatric population promises potential for imaging other internal organs. Although CEUS applications of the spleen, gallbladder and pancreas have been well described in adults, they have not been fully explored in children. In this manuscript, we present an overview of the applications of CEUS for normal variants and diseases affecting the spleen, gallbladder and pancreas. We highlight a variety of cases as examples of how CEUS can serve in the diagnosis and follow-up for such diseases in children. Our discussion includes specific examination techniques; presentation of the main imaging findings in various benign and malignant lesions of the spleen, gallbladder and pancreas in children; and acknowledgment of the limitations of CEUS for these organs.

WFUMB Position Paper-Incidental Findings, How to Manage: Spleen

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental Imaging Findings-The Role of Medical Ultrasound." IFs are less commonly encountered in the spleen than in many other abdominal organs but remain a frequent dilemma in clinical practice. A histological diagnosis is rarely necessary for patient management. Many IFs, such as secondary spleens and splenic cysts, are harmless and do not require any further investigation. The diagnosis of many other focal splenic lesions is, however, often problematic. The following overview is intended to illustrate a variety of incidentally detected spleen pathologies such as size variants, shape variants, secondary spleens, focal splenic lesions and splenic calcifications. It should aid the examiner in establishing the diagnosis. Moreover, it should help the ultrasound practitioner decide which pathologies need no further investigation, those requiring interval imaging and cases in which immediate further diagnostic procedures are required.

Perspectives on high resolution microvascular imaging with contrast ultrasound

Recent developments in contrast enhanced ultrasound have demonstrated a potential to visualize small blood vessels in vivo, unlike anything possible with traditional grayscale ultrasound. This Perspective article introduces microvascular imaging strategies and their underlying technology.

[Point-of-Care Ultrasound: Teaching and Learning in Ifakara, Tanzania]

Point-of-Care Ultrasound: Teaching and Learning in Ifakara, Tanzania Abstract. Presentation of two practical cases from the point-of-care ultrasound class in Ifakara, Tanzania. The first case shows the sonographic findings of tuberculosis with findings in the lungs, heart, abdominal lymph nodes and spleen. In the second case, detection of an enterobiliary fistula by sonographic live imaging of air passing from the intestine into the gall bladder and causing non-iatrogenic pneumobilia.

Common and uncommon features of focal splenic lesions on contrast-enhanced ultrasound: a pictorial review

The characterization of focal splenic lesions by ultrasound can be quite challenging. The recent introduction of contrast-enhanced ultrasound (CEUS) has come to play a valuable role in the field of imaging splenic pathologies, offering the possibility of an ionizing radiation-free investigation. Because CEUS has been incorporated into everyday clinical practice, malignant diseases such as focal lymphomatous infiltration, metastatic deposits, benign cysts, traumatic fractures, and hemangiomas can now be accurately depicted and characterized without the need for further imaging. More specifically, splenic traumatic fractures do not require additional imaging by computed tomography (with ionizing radiation exposure) for follow-up, because splenic fractures and their complications are safely imaged with CEUS. In the new era of CEUS, more patients benefit from radiation-free investigation of splenic pathologies with high diagnostic accuracy.

Extended Small-Dose Platelet Transfusions in Multitransfused Hemato-Oncological Patients: A Single-Center Experience

BACKGROUND

Refractoriness to platelet transfusion, prevalent among 15-20% of hemato-oncological patients, is associated with multitransfusions and inferior outcomes. We evaluated the effectiveness of extended slow-dose transfusion (ESDT) in increasing platelet increments in multitransfused patients.

METHODS

Patients treated after the implementation of ESDT were compared with historical controls treated with standard single-donor platelet (SDP) transfusions. Cohorts of early and late recipients were assembled for comparison, i.e. the 8th or 9th and 11th platelet unit per patient, respectively. Patients in the ESDT group received transfusions equal to half an SDP unit, administered over 4 h. Effectiveness was defined as a higher corrected count increment (CCI) at 1, 12, and 24 h after transfusion.

RESULTS

In the early-recipients cohort, 24-h-posttransfusion increments were available for 29 ESDT patients and 6 standard patients, and did not differ significantly between the groups (p = 0.078). The 24-h-posttransfusion increment was available for 20 ESDT patients and 7 standard patients in the late-recipients cohort. The CCI was significantly higher in the ESDT group (p = 0.042). ABO compatibility improved the CCI (p = 0.01).

CONCLUSIONS

ESDT demonstrated slightly higher increments at 24 h after transfusion in late recipients, suggesting this could be a cost-effective approach for the treatment of thrombocytopenic multitransfused hemato-oncological patients.

Primary splenic lymphoma: Current diagnostic trends

The primary splenic lymphoma is extremely uncommon, can present with grave complications like hypersplenism and splenic rupture. In view of vague clinical presentation, it is difficult to arrive at the diagnosis. In such circumstances, histopathological diagnosis is very important. A precise diagnosis can only be made on histopathology and confirmed on immunohistochemistry.Emergency splenectomy is preferred as an effective therapeutic and diagnostic tool in cases with giant splenomegaly. Core biopsy is usually not advised due to a high risk of post-core biopsy complications in view of its high vascularity and fragility. Aim behind highlighting the topic is to specify that core biopsy/ fine needle aspiration cytology can be used as an effective diagnostic tool to arrive at correct diagnosis to prevent untoward complications related to disease and treatment. Anticoagulation therapy is vital after splenectomy to avoid portal splenic vein thrombosis.

Wandering spleen torsion-use of contrast-enhanced ultrasound

We report a case of torsion of a wandering spleen in an 18-year-old male patient who presented with acute abdominal pain and left lower quadrant mass. The patient was initially misdiagnosed at another institution. The patient came to our hospital for further investigation. Contrast-enhanced ultrasound was performed and showed a solid hypoechoic avascular mass, which was all that remained of the spleen, located under the left kidney. Based on the ultrasound findings, CT scan and MRI of the abdomen were performed to confirm the suspicion of torsion of a wandering spleen. To the best of our knowledge, there are no case reports describing the use of contrast-enhanced ultrasound for diagnosing torsion of a wandering spleen.

Evaluating Patients with Left Upper Quadrant Pain

Imaging plays a major role in the evaluation of patients who present to the emergency department with acute left upper quadrant (LUQ) pain. Multidetector computed tomography is currently the primary modality used for imaging these patients. The peritoneal reflections, subperitoneal compartment, and peritoneal spaces of the LUQ are key anatomic features in understanding the imaging appearance of acute diseases in this area. Diseases of the stomach, spleen, pancreas, and splenic flexure are encountered in patients with acute LUQ pain. Optimization of the imaging protocol is vital for accurate diagnosis and characterization of these diseases in the acute setting.

Coexistence of splenic hemangioma and vascular malformation of the vertebrae

Background

Cavernous hemangioma is an encapsulated mass of dilated, endothelial lined vascular channels filled with slowly flowing blood. Cavernous hemangioma of the spleen is a rare condition with less than 100 reports so far. Hemangioma of the vertebral is a benign vascular legion around one or two vertebrae. These are usually asymptomatic and discovered incidentally. In this study we reported an extreme rare case of splenic hemangioma coexistence with vascular malformation of the vertebrae. To our knowledge this is the first report of coexistence of splenic hemangioma and hemangioma of the vertebra.

Case presentation

A 20-year-old iranian male with splenomegaly, abdominal pain, diarrhea and pancytopenia who was first highly suspicious for malignancy referred to our center for evaluation of the diagnostic workup. After full examination we detected a very rare case with a giant, solitary cavernous hemangioma of the spleen and multiple hemangiomas in his vertebrae. Histopathology of the spleen showed a large cavernous hemangioma occupying almost the entire spleen with large areas of infarction necrosis with multiple hemangiomas of the vertebrae.

Conclusion

It is extremely rare to have a splenic hemangioma concurrent with vertebra hemangioma and this is clinically very important to consider splenic hemangioma in differential diagnosis of splenomegaly for a better therapeutic management in related patients.

Multiparametric sonographic imaging of a capillary hemangioma of the testis: appearances on gray-scale, color Doppler, contrast-enhanced ultrasound and strain elastography

We report a case of a lobular capillary hemangioma in a 66-year-old man, who presented with left testicular pain, with an asymptomatic incidental right testicular lesion found on ultrasonography. The sonographic examination demonstrated a heterogeneous mainly iso-echoic intratesticular lesion with marked vascularity on the color Doppler examination. Further evaluation with contrast-enhanced ultrasound and strain elastography was performed; the multiparametric imaging suggested a benign tumor. The multidisciplinary team decision with patient consent was to perform a radical orchiectomy with subsequent histopathology confirming a benign lobular capillary hemangioma.

Contrast-enhanced sonography with Sonazoid as a new diagnostic tool for splenic hamartoma: a single case report

Detection of reticuloendothelial system (RES) cells is essential for the differential diagnosis of splenic hamartoma. Among the imaging techniques using contrast agents phagocytosed by RES cells, contrast-enhanced ultrasonography (CEUS) with Sonazoid is less invasive and less costly than (99m)Tc-labeled colloid scintigraphy. We report a case of non-symptomatic splenic hamartoma in a 40-year-old woman detected as an abdominal tumor by screening ultrasonography. The tumor was 4 cm in diameter, round, slightly hypoechoic, and associated with a cystic lesion. The tumor region was stained on enhanced computed tomography with prolonged enhancement, while the cystic lesion was not. The mass appeared as mainly isointense with partial hyperintensity on T1-weighted and as a mixed hypo- and hyperintense region on T2-weighted magnetic resonance images. (99m)Tc-labeled colloid scintigraphy demonstrated uptake in only the tumor region. CEUS with Sonazoid revealed that the tumor was mainly hypervascular with non-enhanced areas in the early vascular phase, but the hypervascular region appeared also as a hyperechoic area (indicating microbubble phagocytosis) in the post-vascular phase. Thus, CEUS with Sonazoid revealed all three cardinal features of splenic hamartoma: hypervascularity, presence of RES cells, and tissue heterogeneity. Splenectomy and histopathology confirmed the presence of a splenic hamartoma with associated hematoma. CEUS with Sonazoid is a promising new diagnostic tool for splenic hamartoma.

The sonographic "bright band sign" of splenic infarction

OBJECTIVES

To evaluate the frequency of the "bright band sign" in patients with splenic infarcts as well as control patients and to thereby assess whether the bright band sign has potential utility as a sonographic sign of splenic infarction.

METHODS

Using an electronic search engine and image review, 37 patients were retrospectively identified with noncystic parenchymal splenic infarcts on sonography. Nineteen abnormal control patients with noninfarcted splenic lesions on sonography and 100 normal control patients with sonographically normal spleens were also identified. The sonographic appearance of each splenic lesion was evaluated by 2 reviewers and assessed for the bright band sign, defined as thin specular reflectors perpendicular to the sound beam within hypoechoic parenchymal lesions, and for the presence or absence of the classic sonographic appearance of splenic infarction. Possible histologic counterparts of the bright band sign were assessed in archival infarct specimens.

RESULTS

The bright band sign was present in 34 (91.9%; 95% confidence interval [CI], 78.1%-98.3%) of 37 patients with splenic infarcts on sonography, including 12 (85.7%; 95% CI, 57.2%-98.2%) of 14 with classic and 22 (95.7%; 95% CI, 78.1%-99.9%) of 23 with nonclassic infarct appearances. No normal or abnormal control patients had the bright band sign. Histologic sections suggested that preserved splenic trabeculae within infarcts may generate the bright band sign.

CONCLUSIONS

The bright band sign is a potentially useful sonographic sign of splenic infarction, which may confer additional sensitivity and specificity and may be particularly helpful with infarcts having nonclassic appearances.

Assessing splenomegaly: automated volumetric analysis of the spleen

RATIONALE AND OBJECTIVES

To define systematic volumetric thresholds to identify and grade splenomegaly and retrospectively evaluate the performance of radiologists to assess splenomegaly in computed tomography (CT) image data.

MATERIALS AND METHODS

A clinical tool was developed to segment spleens from 172 contrast-enhanced clinical CT studies. There were 45 normal and 127 splenomegaly cases confirmed by radiological reports. Spleen volumes were compared to manual measurements using overlap/error. Volumetric thresholds for mild/massive splenomegaly were defined at 1/2.5 standard deviations above the average splenic volume of the healthy population. The thresholds were validated against consensus reports. The performance of radiologists in assessing splenomegaly was retrospectively evaluated.

RESULTS

The automated segmentation of spleens was robust with volume overlap/error of 95.2/3.3%. There were no significant differences (P > .2) between manual and automated segmentations for either normal/splenomegaly subgroups. Comparable correlations between interobserver and manual-automated measurements were found (r = 0.99 for all). The average volume of normal spleens was 236.89 ± 77.58 mL. For splenomegaly, average volume was 1004.75 ± 644.27 mL. Volumetric thresholds of 314.47/430.84 mL were used to define mild/massive splenomegaly (±18.86 mL, 95% CI). Radiologists disagreed in 23.25% (n = 40) of the diagnosed cases. The area under the receiver operating characteristic curve of the volumetric criterion for splenomegaly detection was 0.96. Using the volumetric thresholds as the reference standard, the sensitivity of radiologists in detecting all/mild/massive splenomegaly was 95.0/66.6/99.0% at 78.0% specificity, respectively.

CONCLUSION

Thresholds for the identification and grading of splenomegaly from automatic volumetric spleen assessment were introduced. The volumetric thresholds match well with clinical interpretations for splenomegaly and may improve splenomegaly detection compared with splenic cephalocaudal height measurements or visual inspection commonly used in current clinical practice.

Splenic hemangiomas: contrast-enhanced sonographic findings

OBJECTIVES

The purpose of this study was to illustrate the baseline appearance and enhancement patterns of splenic hemangiomas on contrast-enhanced sonography.

METHODS

Two experienced radiologists retrospectively reviewed by consensus baseline and contrast-enhanced sonographic examinations of 27 patients (14 women and 13 men; mean age, 58.7 years) with 27 splenic hemangiomas (mean size, 2 cm) confirmed by splenectomy, biopsy, computed tomography, and magnetic resonance imaging and follow-up.

RESULTS

On baseline sonography, 77.8% of the lesions showed a homogeneous echo texture that was mainly hyperechoic. Color Doppler imaging did not show any signal in 81.5% of the cases. After contrast agent injection, 59.2% of the splenic hemangiomas showed different degrees of contrast enhancement in the arterial phase followed by isoenhancement in the late parenchymal phase. Among these, 2 hemangiomas showed peripheral globular enhancement in the arterial phase, followed by progressive centripetal fill-in. In 29.6% of the cases, some degree of contrast enhancement was appreciable, but the hemangiomas remained substantially hypoechoic throughout the contrast-enhanced sonographic examinations, whereas in 11.1%, the combination of contrast enhancement in the arterial phase followed by wash-out in the late parenchymal phase was evident.

CONCLUSIONS

Isoechogenicity to spleen parenchyma in all phases is the most frequent typical enhancement pattern of splenic hemangiomas observed on contrast-enhanced sonography. Nevertheless, these lesions may show atypical contrast enhancement patterns; therefore, further assessment with cross-sectional techniques is needed.

Characterization of nontraumatic focal splenic lesions using contrast-enhanced sonography

PURPOSE

To compare contrast-enhanced sonography (CEUS) with contrast-enhanced CT in the assessment of nontraumatic focal lesions of the spleen.

METHODS

CEUS and CT findings in 22 patients with fever of unknown origin and ultrasound-detected splenic focal lesions were analyzed retrospectively. CEUS was performed using an ultrasound unit equipped with a 3.6-MHz probe and contrast-specific software. A 4-ml bolus of second-generation contrast medium was used. The CEUS examinations included a 4-minute recording following injection of the contrast medium. MRI, splenic biopsy, or ultrasound follow-up were used if findings from CT were inconclusive.

RESULTS

The final diagnoses were as follows: seven splenic infarcts, five hemangiomas, three lacerations, two benign cysts, one lymphoma, one granuloma, one abscess, and two lesions of unknown etiology. CEUS and CT had the same specificity (77.2%). Both CEUS and CT failed to characterize nodular hypovascular lesions with a hypoenhancing pattern.

CONCLUSIONS

CEUS is as effective as CT for characterizing nontraumatic focal lesions of the spleen. If CEUS findings are consistent with a benign splenic lesion, CT seems to be of limited additional value.

How I diagnose and treat splenic lymphomas

The incidental finding of an isolated splenomegaly during clinical assessment of patients evaluated for unrelated causes has become increasingly frequent because of the widespread use of imaging. Therefore, the challenging approach to the differential diagnosis of spleen disorders has emerged as a rather common issue of clinical practice. A true diagnostic dilemma hides in distinguishing pathologic conditions primarily involving the spleen from those in which splenomegaly presents as an epiphenomenon of hepatic or systemic diseases. Among the causes of isolated splenomegaly, lymphoid malignancies account for a relevant, yet probably underestimated, number of cases. Splenic lymphomas constitute a wide and heterogeneous array of diseases, whose clinical behavior spans from indolent to highly aggressive. Such a clinical heterogeneity is paralleled by the high degree of biologic variation in the lymphoid populations from which they originate. Nevertheless, the presenting clinical, laboratory, and pathologic features of these diseases often display significant overlaps. In this manuscript, we present our approach to the diagnosis and treatment of these rare lymphomas, whose complexity has been so far determined by the lack of prospectively validated prognostic systems, treatment strategies, and response criteria.

Contrast enhanced ultrasound of splenic lymphoma involvement

OBJECTIVE

The aim of this study was to compare the value of contrast-enhanced ultrasonography (CEUS) with standard B-mode ultrasound (US) for diagnosis of splenic lymphoma involvement.

METHODS

From 04/2005 to 10/2008 n=250 lymphoma patients were investigated by standard B-mode US. A homogeneous splenic echotexture was found in 199 patients (79%). To clarify the benefit of CEUS in this group a pilot series was performed with 16 of the 199 lymphoma patients. All patients with an abnormal splenic echotexture on standard B-Mode US (n=51) including focal hypoechoic splenic lesions (n=41) and an inhomogeneous splenic texture (n=10) were studied by CEUS. CEUS data were retrospectively evaluated. The diagnoses included indolent lymphoma (n=27), aggressive lymphoma (n=14), and Hodgkin's disease (n=10). Number and size of lesions were determined by B-mode US and CEUS. The visualisation of splenic lymphoma involvement by CEUS in comparison to B-mode US was classified as worse, equal, or better.

RESULTS

All patients with a homogeneous spleen on B-mode US (n=16) had no visible focal lesions on CEUS. Study patients with focal lesions (n=41) had a hypoechoic (n=22) or isoechoic (n=19) enhancement during the arterial phase, and a hypoechoic enhancement during the parenchymal phase (n=41). The visualisation of focal splenic lymphoma was equal (n=32), better (n=6), or worse (n=3). In all study patients with an inhomogeneous spleen on B-mode US (n=10) no focal lesions were found by CEUS and the value of CEUS therefore was classified as worse.

CONCLUSION

CEUS has no clear advantage for diagnosis of splenic lymphoma involvement.

Differentiation of benign from malignant focal splenic lesions using sulfur hexafluoride-filled microbubble contrast-enhanced pulse-inversion sonography

OBJECTIVE

The purpose of our study was to evaluate whether sonographic characterization of focal splenic lesions could be improved by using low mechanical index pulse-inversion sonography after sulfur hexafluoride-filled microbubble injection.

MATERIALS AND METHODS

One hundred forty-seven splenic lesions (68 benign, 79 malignant) in 147 patients (81 men, 66 women; mean age, 51 years) underwent baseline gray-scale sonography and sulfur hexafluoride-enhanced low-acoustic-power pulse-inversion sonography (mechanical index < 0.1). Two site investigators assessed in consensus lesion and splenic enhancement during arterial and parenchymal phases. Four readers (readers 1 and 2, blinded; and readers 3 and 4, unblinded to clinical data) independently reviewed baseline and contrast-enhanced sonograms and provided confidence rating for diagnosis of malignancy or benignancy. Accuracy, sensitivity, specificity, positive and negative predictive values, and areas under the receiver operating characteristic curves (A(z)) were calculated by considering biopsy results or splenectomy (51 patients) or CT or MR images followed by serial sonography 6-12 months apart (96 patients) as reference standards.

RESULTS

Benign lesions appeared predominately non- or isoenhancing relative to splenic parenchyma, whereas malignant lesions appeared predominately progressively hypoenhancing. For correct diagnosis of benignancy or malignancy, review of contrast-enhanced sonography after baseline sonography yielded significantly improved diagnostic performance (overall accuracy, 51%, 43%, 70%, and 74% before vs 83%, 81%, 92%, and 91% after contrast-enhanced sonography for readers 1, 2, 3, and 4; p < 0.05; respectively) and significantly improved diagnostic confidence (A(z), 0.770, 0.678, 0.900, and 0.917 before vs 0.935, 0.917, 0.984, and 0.959 after contrast-enhanced sonography for readers 1, 2, 3, and 4; p < 0.05; respectively).

CONCLUSION

Sulfur hexafluoride-filled microbubble-enhanced sonography improves characterization of focal splenic lesions with and without the availability of clinical data.

Pediatric blunt splenic trauma: a comprehensive review

Abdominal trauma is a leading cause of death in children older than 1 year of age. The spleen is the most common organ injured following blunt abdominal trauma. Pediatric trauma patients present unique clinical challenges as compared to adults, including different mechanisms of injury, physiologic responses, and indications for operative versus nonoperative management. Splenic salvage techniques and nonoperative approaches are preferred to splenectomy in order to decrease perioperative risks, transfusion needs, duration/cost of hospitalization, and risk of overwhelming postsplenectomy infection. Early and accurate detection of splenic injury is critical in both adults and children; however, while imaging findings guide management in adults, hemodynamic stability is the primary determinant in pediatric patients. After initial diagnosis, the primary role of imaging in pediatric patients is to determine the level and duration of care. We present a comprehensive literature review regarding the mechanism of injury, imaging, management, and complications of traumatic splenic injury in pediatric patients. Multiple patients are presented with an emphasis on the American Association for the Surgery of Trauma organ injury grading system. Clinical practice guidelines from the American Pediatric Surgical Association are discussed and compared with our experience at a large community hospital, with recommendations for future practice guidelines.

Contrast-enhanced ultrasonography in nodular splenomegaly associated with type B Niemann-Pick disease: an atypical hemangioma enhancement pattern

INTRODUCTION

Niemann-Pick disease (NPD) types A and B are lipid storage disorders. NPD type A is a fatal disorder of infancy. Type B is a non-neuronopathic form observed in children and adults. It is associated with enlargement of the liver, spleen, or both, and nodular splenomegaly may be detected with ultrasound.

METHODS

A 21-year-old female was admitted to the Emergency Room with fever, pharyngitis, and left upper quadrant abdominal pain. Labwork revealed anemia, thrombocytopenia, increased levels of AST, ALT, GGT, AF, LDH, triglycerides, and total cholesterol and low levels of HDL-cholesterol. PCR blood assays for CMV and EBV were both negative. Chest X-ray was unremarkable. Transabdominal B-mode ultrasound (US) revealed splenomegaly (long axis: >22 cm), an irregular subcapsular hypoechoic lesion in the superior pole that was consistent with splenic infarction, and multiple round highly echogenic nodes measuring 1-5 cm in diameter. Contrast-enhanced ultrasonography (CEUS) was performed using SonoVue(®) (Bracco).

RESULTS

The presence of a splenic infarction was confirmed. The nodular lesions showed arterial-phase enhancement with late parenchymal phase wash-out. (18)F-FDG-PET revealed splenic nodular uptake. Primary splenic lymphoma was suspected, and the patient underwent open splenectomy. The diagnosis was type B NPD with splenic hemangiomas.

DISCUSSION

CEUS confirmed the diagnosis and extent of splenic infarction, but the nodular atypical enhancement pattern together with nodular (18)F-FDG-PET uptake was misleading, suggesting as it did lymphoproliferative involvement of the spleen.

Contrast-enhanced ultrasonography with SonoVue: differentiation between benign and malignant lesions of the spleen

OBJECTIVE

We investigated the ability of contrast-enhanced ultrasonography with SonoVue (Bracco SpA, Milan, Italy), a sulfur hexafluoride microbubble contrast agent, to reveal differences between benign and malignant focal splenic lesions.

METHODS

In a prospective study we investigated 35 lesions in 35 patients (24 male and 11 female; mean age +/- SD, 54 +/- 15 years) with focal splenic lesions detected by B-mode ultrasonography. After intravenous injection of 1.2 to 2.4 mL of SonoVue, the spleen was examined continuously for 3 minutes using low-mechanical index ultrasonography with contrast-specific software. The final diagnosis was established by histologic examination, computed tomography, or magnetic resonance imaging.

RESULTS

In 14 patients, the splenic lesions were malignant (metastasis, n = 6; non-Hodgkin lymphoma, n = 6; and Hodgkin lymphoma, n = 2). In 21 patients, the focal splenic lesions were benign (ischemic lesion, n = 6; echogenic cyst, n = 5; abscess, n = 4; hemangioma, n = 3; hematoma, n = 1; hemophagocytosis syndrome, n = 1; and splenoma, n = 1. Typical findings for benign lesions were 2 arrival patterns: no contrast enhancement (neither in the early nor in the parenchymal phase; P < .05) and the beginning of contrast enhancement in the early phase followed by contrast enhancement in the parenchymal phase 60 seconds after injection. In contrast, the combination of contrast enhancement in the early phase followed by rapid wash-out and demarcation of the lesion without contrast enhancement in the parenchymal phase (60 seconds after injection) was typical for malignant lesions (P < .001).

CONCLUSIONS

Contrast-enhanced ultrasonography is helpful in the differentiation between benign and malignant lesions of the spleen.

Splenomegaly: investigation, diagnosis and management

Splenomegaly is a feature of a broad range of diseases, and presents to clinicians in many fields. This review examines the aetiology of splenomegaly in the developed world, and describes a logical approach to the patient with splenomegaly. In some patients, extensive radiological and laboratory investigations will fail to yield a diagnosis: these cases of "isolated" splenomegaly are not uncommon and can be particularly challenging to manage. The risks of serious underlying disease must be balanced against the risks of invasive investigations such as splenic biopsy and diagnostic splenectomy. We discuss the options in isolated splenomegaly and their evidence base, and incorporate them into a management strategy to aid the clinician in cases of diagnostic difficulty.

Multiple lesions of the spleen: differential diagnosis of cystic and solid lesions

Lesions in the spleen may be encountered in a variety of clinical settings ranging from asymptomatic patients to patients who are critically ill. Etiologies for multifocal splenic lesions include infectious and inflammatory processes, primary vascular and lymphoid neoplasms, metastatic disease, vascular processes, and systemic diseases. There is often overlap in the imaging appearance alone, so the clinical setting is very helpful in differential diagnosis. In the immunocompromised patient, multiple small splenic lesions usually represent disseminated fungal disease and microabscesses. The spleen is a relatively rare site for metastatic disease; patients with metastatic lesions in the spleen usually have disease in other sites as well. Breast, lung, ovary, melanoma, and colon cancer are common primary tumors that metastasize to the spleen. Vascular neoplasms of the spleen represent the majority of the nonhematologic/nonlymphoid neoplasms and commonly produce multifocal lesions. Splenic infarcts may be seen with localized processes such as portal hypertension or pancreatitis, or may arise from an embolic source. Radiologists should be aware of the spectrum of processes that may involve the spleen and the clinical context in which they occur.

Colour Doppler ultrasound patterns and clinical follow-up of incidentally found hypoechoic, vascular tumours of the spleen: evidence for a benign tumour

Between January 1990 and January 2005, incidental hypoechoic, vascular tumours of the spleen were identified in 13 patients using B-mode and colour Doppler ultrasound (CDS). All lesions found were well demarcated, intrasplenically located, and ranged in size between 1 cm and 4 cm. The increased vascular pattern on CDS was confirmed in 9 of the 13 cases by contrast enhanced ultrasound (CES), while two patients showed reduced vascularity on CES. In 10 patients, lesions were confirmed by contrast enhanced CT. Histological examination was performed in three patients with the diagnosis of capillary haemangioma (n = 2) and hamartoma (n = 1). In the remaining cases, ultrasound follow-up was performed (range 4 months to 13 years) and demonstrated no evidence of tumour growth in all but one patient. During a 4 year follow-up, one lesion increased in size from 1.0 cm to 1.5 cm and in the same patient an additional 0.5 cm sized hypoechoic increased vascular lesion was also found. In the spleen a hypoechoic lesion with an increased vascular pattern incidentally found by ultrasound most likely indicates a benign tumour with capillary haemangioma/hamartoma as the most likely diagnosis. However, it should be emphasised that in all cases a careful ultrasound follow-up is warranted.

Contrast-enhanced sonography for differential diagnosis of an inhomogeneous spleen of unknown cause in patients with pain in the left upper quadrant

OBJECTIVE

Second-generation contrast agents have shown spleen-specific uptake. The aim of this study was to investigate the ability of contrast-enhanced sonography (CES) to demarcate splenic lesions in patients with pain in the left upper quadrant (LUQ) and an inhomogeneous splenic texture.

METHODS

From October 2003 to July 2005, 31 consecutive patients with pain in the LUQ and splenic inhomogeneity on B-mode sonography were studied by CES using a second-generation contrast agent (SonoVue; Bracco SpA, Milan, Italy). The following data were retrospectively evaluated: extent of enhancement (EE) of the spleen and focal splenic lesions was determined and classified, with the EE of surrounding tissue used as an in vivo reference. Focal splenic lesions were classified after CES as round or wedge shaped, solitary or multiple, and anechoic, hypoechoic, or hyperechoic.

RESULTS

The EE of the spleen after CES was anechoic (n = 1), hypoechoic (n = 1), or hyperechoic (n = 29). In 16 of 31 patients, focal lesions were seen after CES. The EE of the lesions was anechoic (n = 11) or hypoechoic (n = 5). Lesions were solitary (n = 6) or multiple (n = 10) and round (n = 5) or wedge shaped (n = 11). Final clinical diagnoses of splenic abnormalities were no specific diagnosis (n = 13), complete autosplenectomy (n = 2), splenic lymphoma (n = 5), and splenic infarction (n = 11). The CES diagnoses were confirmed by computed tomography (n = 21), scintigraphy (n = 2), magnetic resonance imaging (n = 1), and clinical follow-up (n = 7).

CONCLUSIONS

In patients with pain in the LUQ and splenic inhomogeneity, CES enables visualization of splenic abnormalities in more than 50% of the patients; in this group, splenic infarction was the most common diagnosis.