http://acr.sagepub.com/Acta Radiologica

http://acr.sagepub.com/content/early/2013/07/04/0284185113488020The online version of this article can be found at:

 DOI: 10.1177/0284185113488020

published online 4 July 2013Acta RadiolM Schulze, D Spira, CD Claussen, A Sauter, F Mayer and M Horger

volume perfusion techniqueCharacterization of incidental cardiac masses in oncological patients using a new CT-based tumor

  

Published by:

http://www.sagepublications.com

On behalf of: 

Nordic Society of Medical Radiology

can be found at:Acta RadiologicaAdditional services and information for    

  http://acr.sagepub.com/cgi/alertsEmail Alerts:

 

http://acr.sagepub.com/subscriptionsSubscriptions:  

http://www.sagepub.com/journalsReprints.navReprints:  

http://www.sagepub.com/journalsPermissions.navPermissions:  

What is This? 

- Jul 4, 2013 OnlineFirst Version of Record>>

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

Review article

Characterization of incidental cardiac masses in oncological

patients using a new CT-based tumor volume perfusion technique

M Schulze1, D Spira1, CD Claussen1, A Sauter1, F Mayer2 and M Horger1

1Department of Diagnostic and Interventional Radiology; 2Department of Internal Medicine-Oncology, Eberhard-Karls-University,

Tubingen, Germany

Correspondence to: M Horger. Email: marius.horger@med.uni-tuebingen.de

AbstractCardiac masses are challenging for non-invasive diagnostic procedures and therapy, respectively. In tumor

patients differentiation between primary or secondary cardiac neoplasm and thrombus is a frequent and

knowingly difficult task to manage. To avoid complex and unnecessary surgical diagnostic procedures

non-invasive methods are in favor. For initiation of adequate therapy and evaluation of prognosis, however,

early and reliable diagnosis is mandatory.

So far, echocardiography and magnetic resonance imaging represent the mainstay for cardiac imaging

diagnosis. Recently, the new technique of CT-based tumor volume perfusion (VPCT) measurement has

advanced to a potent, reliable, and easy to perform alternative for cardiac imaging. The purpose of this study

was to review the existing spectrum of diagnostic modalities for characterization of cardiac masses in an

oncologic patient cohort with emphasis on their strengths and limitations and to present the benefit from

using the novel technique called VPCT for this purpose.

Keywords: Volume perfusion CT (VPCT), cardiac tumor, intracardiac thrombus

Submitted August 1, 2012; accepted for publication March 25, 2013

The overall frequency of cardiac tumors is fairly low, withan estimated cumulative prevalence of 0.002–0.3% (1).Primary cardiac tumors are very rare, encompassing mul-tiple entities, whereas secondary (metastatic) cardiactumors and larger blood clots are more frequently seen(2–4). In oncologic patients, the incidence of metastaticinvolvement of the heart is consistently higher, lying in arange of 10–12% (1). Therefore, differentiation of metastaticcardiac tumors from blood clots represents a challengein the everyday work-up of oncologic patients. In principle,most malignant tumors can cause cardiac metastases. Mostcommon entities are lung cancer, malignant melanoma,renal cell carcinoma, hepatocellular carcinoma as well aslymphoma and leukemia (5, 6).

Metastatic routes of tumor spread to the heart are mani-fold. Retrograde spread along the mediastinal lymphaticsmostly leads to implantation in the epicardial myocar-dium, causing pericardial effusions. Hematogenousspread to the heart usually occurs with melanomas andsarcomas, whereas direct extension and invasion maybe seen usually with bronchial, breast, and esophagealtumors due to their proximity to the heart (1). Direct

transvenous extension can also occur, particularly withhepatocellular carcinoma and renal cell carcinoma, and isoften accompanied by embedded or attached thromboticparts.

The clinical symptoms of cardiac tumors are related totheir size and location. They may cause alterations incardiac function, related to pericardial effusion, intracardiacobstruction, interference with conduction pathways andembolization, or may even be clinically silent for a longtime and thus elude diagnosis.

In contrast to cardiac metastases, blood clots are the mostfrequently found cardiac chamber masses, mostly involvingthe left ventricle or left atrium (7). Intracardiac clot for-mation is primarily associated with different forms ofcardiac diseases, particularly those which go along withreduced or dyskinetic myocardial contractility (8), butcoagulation disorders in tumor patients are known toaccount for considerable cases of intracardiac clots ascompared with healthy individuals (9). For the initiationof therapy and the evaluation of prognosis in oncologicpatients, differentiation between secondary cardiac tumorsand blood clots is, however, crucial.

Acta Radiologica 2013: 1–9. DOI: 10.1177/0284185113488020

Acta Radiol OnlineFirst, published on July 4, 2013 as doi:10.1177/0284185113488020

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

Imaging of intracardiac masses

Echocardiography

Transthoracic echocardiography (TTE) is used as a screeningtechnique in patients with a suspected intracardiac massbeing capable to detect, localize, and determine mobility

of cardiac masses as well as their relation to important ad-jacent structures like cardiac valves. It has a reportedsensitivity and specificity of 90% and 95%, respectively(10). However, with respect to characterization of cardiacmasses, TTE has limited potential as most of them do notexhibit specific echogenicity. In fact, TTE proves often

Table 1 Mean values for tissue perfusion in the myocardium, collapsed lung parenchyma, and in primaries known to be responsible for mostcommon secondary cardiac tumors as measured by volume perfusion-CT (VPCT)

BF (SD); (range) BV (SD) TTP (SD) k-trans (SD) ALP� PVP�

Myocardium 101.39 (23.54) 27.61 (10.03) 13.52 (2.63) 26.41 (20.99) – –

Muscle (paravertebral) 13.05 (2.80) 3.84 (3.19) 16.93 (3.20) 10.55 (3.48) – –

Liver (ref. 32) – – – – 9.3 (4.1) 88.1 (24.6)

Hepatocellular carcinoma

(ref. 33)

46.3 (10.0–86.4) 20.4 (4.2–42.8) 18.7 (10.1–53.2) 28.03 (10.49–55.19)† 42.9 (13.5–91.8) 1.8 (0–120.5)

RCC 88.30 (30.27) 27.28 (14.70) 16.69 (3.77) 47.22 (32.50)

Bronchial carcinoma 33.17 (7.92) 5.08 (1.63) 14.89 (1.06) 21.92 (5.2)

Atelectasis 37.32 (6.66) 7.57 (2.71) 22.44 (3.00) 35.61 (8.80)

�Applicable only for dual liver perfusion quantification†Own HCC data

ALP, arterial liver perfusion; BF, blood flow in mL/100 mL tissue/min; BV, blood volume in mL/100 mL tissue; MTT, mean transit time in seconds; PVP,

portal-venous perfusion; SD, standard deviation; TTP, time to peak in seconds; k-trans in mL/100 mL tissue/min

Fig. 1 A 63-year-old male patient with histologically confirmed adenocarcinoma of the lung. (a) There is broad-based infiltration of the pericardium along

the right atrium (white arrows) (axial maximum intensity projection [MIP]). Note the low perfusion parameters on blood flow (BF) (23.2 mL/100 mL tissue/min)

(b), blood volume (BV) (6 mL/100 mL tissue) (c), and k-trans (6 mL/100 mL tissue/min) (not shown), especially in the tumor core, as documented on the corre-

sponding color maps. Low perfusion values represent tumor necrosis, which is frequent in lung carcinoma. The tumor is infiltrating the pericardium and

bulging into the dorsal left atrial wall (white arrow)

Fig. 2 An 83-year-old male patient with histologically confirmed metastasis (arrow) of a squamous carcinoma of the lung (a; axial MIP). Note the low perfusion

parameters on the BF (b) and BV (c) color maps due to tumor necrosis. White asterisk indicates the right lobe of the liver

2 M Schulze et al.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

suboptimal due to limited acoustic window and operator-dependent investigational quality (11). Using contrast-enhanced echocardiography (CEUS) differentiation betweentumor and thrombus may become easier by examiningtissue perfusion (12). However, delineation of intracardiacmasses can be limited by the applied contrast medium(particles) as their movement within the heart chambersheavily interfers with mass enhancement. A rate of 25% ofnon-diagnostic scans in microsphere contrast echocardio-graphy was reported by Platt et al. (13). Transesophagealechocardiography (TEE) improves visualization and identi-fication of small masses and lesions in the posterior cardiacsegments. A 100% detection rate of tumors in heart and sur-rounding vessels was reported for TEE compared to a 70%

detection rate for TTE (14). For improvement of temporaland spatial resolution, another technical developmentso-called 3D echocardiography was recommended (10).But, general limitations of echocardiography like operatordependency and limitations in mass discrimination andcharacterization still remain a major problem (15).Furthermore, TEE is limited by its invasive nature, thereforebeing not suitable in patients with, for example, esophagealpathology or unstable angina (16).

Magnetic resonance imaging

Magnetic resonance imaging (MRI) of the heart is con-sidered to be the gold standard for characterization ofcardiac tumors (1, 17–19) as it is non-invasive, operatorindependent, providing orthogonal images with a largefield of view, resulting in additional information comparedto echocardiography in up to 46% of cases (11). MRI cor-rectly characterizes cardiac masses in 75% of cases as com-pared to only 29% in case of TTE and represents thereforethe current state-of-the art technique for accurate character-ization of cardiac masses. Using “black-blood” sequencesvisualization of intracavitary masses can be improved bysuppressing blood signal (20). Intramural mass components,extension into the inflow and outflow tract as well asobstruction of the outflow tract can be well demonstratedusing T1-weighted and T2-weighted sequences with stan-dardized angulations (short axis, long-axis, two-chamber,and four-chamber views) and cine gradient echo sequences(21). Levels of agreement of up to 87.8% were reportedbetween MRI and surgical findings regarding the extent ofintravascular tumor infiltration (22). However, the diagnos-tic capability of MRI is also often impaired by significantartifacts resulting from cardiac and respiratory motion,long examination times leading to suboptimal bloodsignal suppression (11). Moreover implants and devicesnot suitable for magnetic field can obviate MRI in patients.Finally, this technique is comparably more time-consumingand of high operational costs.

18F-fluorodeoxyglucose positron emission tomography/computed tomography

In recent years, 18F-FDG PET/CT has emerged as a usefultechnique in fasting oncologic patients able to discriminatebetween benign and malignant cardiac masses. A signifi-cantly higher FDG uptake (sensitivity and specificity of100% and 86%) was found in primary and secondarycardiac malignancies than in benign cardiac masses (23).Nevertheless, a great limitation of this method is the depen-dency of results on FDG-uptake time, blood glucose levels,and insulin medication. Furthermore highly variable andnon-uniform cardiac FDG activity in fasted patients aswell as limited scanner resolution and lack of cardiac andbreathing motion correction often impede a common useof 18F-FDG PET/CT in visualizing cardiac masses (24).Recent data on this field modify initial euphoria attesting18F-FDG PET/CT less confidence in the determinationof malignancy (23). At this point, combining CT perfusion

Fig. 3 A 77-year-old female patient with histologically confirmed soft tissue

sarcoma metastatic to the lung. The tumor has broad contact with the pericar-

dium and is infiltrating the parietal pericardial lining of the anterior left ventri-

cular wall (a; axial MIP). Note the tumor enhancement in BF (51.17 mL/100 mL

tissue/min) (b). Perfusion measurements yielded the following values:

BV (11.2 mL/100 mL tissue) and k-trans (41.11 mL/100 mL tissue/min)

(not shown)

Characterization of incidental cardiac masses in oncological patients 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

with FDG-PET could significantly improve diagnostic accuracyof cardiac tumors.

Computed tomography

For oncologic imaging whole-body multidetector computedtomography (MDCT) represents the mainstay technique dueto its broad accessibility, very short acquisition time andcomparably lower operational costs.

With ECG (electrocardiogram)-gating of CT images, i.e.scanning or reconstruction of raw data at the point of leastcardiac motion images of high spatial and temporal resol-ution can be achieved (25). With the development of newMDCT scanning techniques and software solutions, CTperfusion in its current form has been made faster interms of acquisition time, (approximately 40 s) (26), isfully automated, strengthened by robust motion correction,and is able to quantify perfusion in all tissues, includingcardiac masses. The current volume-perfusion CT (VPCT)technology adds the ability of improved differentiation of

cardiac masses as an adjunct to standardized whole-bodyMDCT imaging in oncological patients.

Hence, the aim of this review was to provide the readerwith background information on the technical advantagesand potential applications of VPCT in the work-up ofincidentally detected cardiac masses and to illustratecardiac disease processes as we observed them in our initialobservation series.

Technical data

VPCT measures temporal changes in tissue density afterintravenous contrast injection using repeated CT scansof the volume being analyzed. Hence, CT attenuationmeasurements include contrast material contained in theintra- as well as extra-vascular space. The density/timecurves of two regions of interest (ROIs), one placed onthe afferent artery and the other on the tissue volumebeing studied, are compared (27, 28). Different kineticmodeling techniques are used by software providers.

Fig. 4 A 62-year-old male patient with histologically proven pleural mesothelioma showing direct invasion of the pericardium, myocardium, and endocardium of

both the right and left atria (white arrows) (a; axial MIP). The tumor is markedly vascularized, showing increased BF (64.9 mL/100 mL tissue/min) (b), BV (17.6 mL/

100 mL tissue) (c), and k-trans (50.8 mL/100 mL tissue/min) (not shown) perfusion values. In the left atrium, there is a small appositional blood clot (black arrow),

clearly delineated by VPCT, displaying some blurring due to its small size

Fig. 5 A 66-year-old male patient with histologically proven hepatocellular carcinoma metastatic to the right ventricle (a; axial MIP). This was assumed to rep-

resent hematogenous spread as there is neither a direct connection to the primary tumor via the inferior vena cava nor an intercalated mass in the right atrium. The

endocardial mass shows high BF (78.6 mL/100 mL tissue/min) (b) and BV (30.9 mL/100 mL tissue) (c) values. Perfusion values correspond to those of the primary

hepatic tumor BF (72.9 mL/100 mL tissue/min). Despite systemic therapy with the tyrosine kinase inhibitor sorafenib, all tumor manifestations, including the

cardiac manifestations, progressed in the short term (not shown)

4 M Schulze et al.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

A one-compartment analysis of short-duration scans duringthe initial phase after contrast-injection enables the calcu-lation of perfusion (blood flow [BF]) and time to peak (TTP),indicating the time interval from arterial enhancementto peak density in the tissue (28, 29). Complementary, atwo-compartment (Patlak) analysis quantifies exchangesbetween intra- and extravascular spaces, and is used inthe interstitial phase to calculate blood volume (BV, exclud-ing stagnant blood) and the volume transfer coefficient(k-trans, defined as the sum of the flow within the micro-vasculature and capillary permeability) (28). A measure-ment time of approximately 40 s has been established asreliable in order to avoid measurement of backflow from

extravascular space to the intravascular compartment (26).At this point, the heart is no doubt the most challengingorgan for VPCT measurement due to considerable intrinsicmotion with considerable size and shape deformation anddiaphragmatic movement during breathing.

At our institution, VPCT measurements have been inte-grated into the routine whole-body MDCT for oncologicimaging, and performed in patients detected with incidentalcardiac masses either by other modalities (e.g. echocardio-graphy) or during staging CT. In the latter case, VPCT wasperformed 15 min after standard CT. Z-axis coverage forchest VPCT using shuttle mode was 6.9 cm. All examinationswere performed on a 128-slice CT scanner (SOMATOM

Fig. 6 A 76-year-old man with histologically proven squamous carcinoma of

the lung (lower right lobe) (a; axial MIP) with necrotic areas (white arrows) and

a new metastatic tumor mass on the medial wall of the right atrium presenting

with primarily equivalent perfusion on VPCT (black arrow). Perfusion analysis

yielded the following values: BF ¼ 73.2 mL/100 mL tissue/min (b), BV ¼

9.8 mL/100 mL tissue (not shown), k-trans ¼ 58.2 ml/100 mL tissue/min (not

shown). Note the marked vascularization of the papillary muscle

connected to the left lateral ventricular wall

Fig. 7 A 76-year-old man with histologically proven hepatocellular carcinoma

showing tumor extension into the right atrium via the inferior vena cava (a; BF,

coronal color map). VPCT blood flow color panels display high perfusion par-

ameters along the middle hepatic vein and inferior vena cava, including the

right atrium, reflecting a highly vascularized intracardiac tumor extension.

Perfusion parameters were BF ¼ 66.3 mL/100 mL tissue/min (a, b) and

BV ¼ 16.6 mL/100 mL tissue). Note that there is some motion-related noise

below the diaphragm at the bottom of the color panel (a)

Characterization of incidental cardiac masses in oncological patients 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

Definition AS plus, SIEMENS Healthcare, Erlangen,Germany), using a standardized protocol. Patients under-went VPCT at the level of the cardiac masses using the follow-ing parameters: 80 kV; 60–80 mAs (dependent on patient’sweight); collimation, 128 � 0.6 mm; 26 scans every 1.5 s.Dose length product (DLP) of VPCT was 186 mGy�cm.Effective dose in male and female patients was 3.5 mSv and6.5 mSv, respectively, as assessed by phantom measurements(30). As an intravenous contrast, we used 50 mL iopromide(Ultravistw 370, Bayer Vital, Leverkusen, Germany) at5 mL/s flow rate followed by a saline flush of 50 mL NaClwith a start delay of 5 s. One set of axial images with a slicethickness of 3 mm for perfusion analysis was reconstructedwithout overlap. All examinations were performed withoutECG gating or breath-holding.

Postprocessing of VPCT data was done on an assignedimage processing workstation. Motion correction and seg-mentation were performed automatically as well as auto-matic arterial vessel identification and vessel segmentationthreshold. Automatic motion correction of the time pointsfor the heart was performed. This allows for correctingtranslational, rotational, and minor shape changes. Then4D Noise Reduction was applied, i.e. a spatiotemporalmultiband filtering algorithm which reduces noise andthereby improves the quality of the perfusion mapswithout losing information about the iodine enhancement.After defining the arterial input function by drawing aregion of interest (ROI) in the aorta, color-coded perfusionparameter maps are generated. In these maps volume ofinterest (VOI) can be drawn within the tissue that is to beanalyzed. Blood flow (BF), blood volume (BV), time topeak (TTP), k-trans, and mean transit time (MTT) withinthe analyzed tissues are finally archived.

VPCT imaging findings in malignant tumors metastatic tothe heart

The main benefit of VPCT as compared to standard chestCT consists in its potential to accurately detect andanalyze the degree of perfusion of a cardiac mass. Due toreliable motion correction, neither ECG nor breath-gating

are usually necessary. Moreover, ECG gating combinedwith VPCT/shuttle mode perfusion measurement remainstechnically challenging, as shuttle mode needs a predefinedrotation time and time interval between measurements(31). Adjustment of intracavitary Hounsfield unit (HU)thresholds enables the subtraction of enhanced blood withoptimal delineation of cardiac masses. Nevertheless, theimage quality of VPCT still differs among the heartchambers, depending on the degree of wall motion through-out the cardiac cycle. Thus, masses arising from the atrial orright ventricular walls or located along the interventricularseptum are generally displayed in better quality comparedto those situated at the free left ventricular wall or apex.In the latter, some degree of blurring, including incompletesubtraction of contrasted blood can occur, particularly whenusing smaller perfusion volumes. Consequently, the greaterthe size of a cardiac mass, the better the quality of detectionand characterization.

The use of VPCT helps primarily for both the exclusionof differentials (e.g. blood clots, flow-related effects, andmotion associated partial volume average) and detailedanalysis of the routes of tumor spread. Table 1 (32, 33) pro-vides a summary of typical perfusion values obtained byvolume perfusion CT in normal myocardium, atelectasis,paravertebral musculature, and liver as well as in sometumors typically known for invading the heart.

Specific findings determining infiltration of heart struc-tures are, according to the definition by Beroukhim et al.(34): (i) crossing an annular or tissue plane within theheart; (ii) involving cardiac and extra-cardiac structures;and (iii) continuous growth through a large vessel into theheart, e.g. vena cava, pulmonary vein.

Sites of metastatic involvement

Metastases involving the pericardium are known to eitherresult from direct invasion of an intrathoracic tumor(Fig. 1a–c) or mediastinal tumor (Fig. 2a–c), or from retro-grade lymphatic spread through tracheal or broncho-mediastinal lymphatic channels. Differential diagnosisincludes malignant pericardial effusion, inflammation, and

Fig. 8 A 50-year-old woman with histologically proven recurrent leiomyosarcoma of the left atrium (black arrow) (a; axial MIP) with measured blood flow of

25.6 mL/100 mL tissue/min (b) and blood volume of 19.2 mL/100 mL tissue (c) extending into the left lower pulmonary vein and reaching the artificial mitral

valve (white arrow). At the distal end, a small appositional thrombus (arrow head) is seen. At follow-up, despite ongoing chemotherapy, the tumor showed

further progress with continuous extension into the left lower pulmonary vein. Due to increased heart rate, blurring artefacts are seen at the tumor margins

6 M Schulze et al.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

fibrosis or drug-induced pericarditis; infection and idio-pathic causes must be excluded. Enhancement of thepericardium or pericardial nodularity suggests malignantinvolvement. Moreover, in patients presenting with focalplaque-like thickening of the pericardial lining apartfrom or next to a lung or mediastinal tumor, perfusionmeasurements can be beneficial for an accurate diagnosis(Fig. 3a, b).

Tumors invading the heart are better displayed byVPCT by accurately documenting the continuous growthof vascularized tissue into the heart wall and chambers(Fig. 4a–c). Complementarily, VPCT can also differentiatebetween tumor invasion and appositional clots secon-dary to impaired mobility of the heart wall. The latter

has immediate therapeutic consequences. Furthermore,differentiation between a tumor invading the heart andatelectasis next to it becomes more confident, as the latterusually presents with higher and more homogeneous per-fusion values. Endocardial metastases are usually theresult of invasion via the bloodstream through the heartchambers (Figs. 5a–c and 6a, b). This pathway is frequentlyseen with tumors originating from the kidney, liver, or lung(3). However, tumor extension along the superior vena cavaand/or the inferior vena cava or via the pulmonary veinsinto the right atrium is also not uncommon (Figs. 7a, b,8a–c, and 9a, b). Therapeutic management in such casesrequires cardiopulmonary bypass after median sternotomy

Fig. 9 A 51-year-old man with histologically proven adenocarcinoma of the

lung showing infiltration of the left pulmonary vein and left atrium reaching

the level of the mitral valve (a). Perfusion values in the tumor core were

BF ¼ 40.06 mL/100 mL tissue/min (b); BV ¼ 6.22 mL/100 mL tissue;

k-trans ¼ 23.36 mL/100 mL tissue/min. Note the presence of diffuse necrosis

in the tumor core with persistent perfusion at the edges of the mass, which is

frequent in bronchial carcinoma (b)

Fig. 10 A 72-year-old man with histologically proven gastric adenocarci-

noma showing a left ventricular, apical intracardial mass in the region of

myocardial thinning (arrow heads) (a; axial MIP). On VPCT (b), the mass

shows no perfusion and marked delineation from the ventricular wall (black

arrow), reflecting an intracardial thrombus, which vanished 6 weeks later

during anticoagulation therapy. There is minimal blurring at the edges of the

thrombus, which should be excluded from the measurement by manual

encompassment

Characterization of incidental cardiac masses in oncological patients 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

as well as a transabdominal incision for resection of themetastatic tumor from the right atrium. Therefore, correctdiagnosis is mandatory.

VPCT imaging findings in heart chamber clots

Differentiation of cardiac metastases from blood clots iscrucial as oncologic patients are at high risk of thromboticcomplications. The estimated annual incidence of theseevents is 0.5% in cancer patients compared to 0.1% in thegeneral population. Clot formation is influenced by manyfactors, including the type of disease, the type of chemother-apy and the use of central venous devices. In most patients,the hypercoagulable state is determined by the biologicalproperties of the tumor (e.g. oncogenes) (4). Clots withinthe cardiac chambers can mimic a primary tumor or meta-static disease (Fig. 10a, b). However, intracardiac bloodclots normally do not enhance after intravenous contrastmaterial administration (35) – only organized thrombusmay show marginal surface enhancement (7) – andusually change in size and shape rapidly over time. In thisclinical setting, VPCT allows for the distinction betweenintracavitary tumors and clots by showing enhancementdue to tumor neovascularity (Figs. 5 and 6).

Conclusion

VPCT is a useful tool for the differentiation of cardiacmasses (metastases vs. clots) found incidentally in oncologicpatients. Software-based motion correction delineatescardiac wall and intracardiac structures well with onlyone limitation regarding perfusion quantification in verysmall lesions. Perfusion parameters of cardiac metastasesand those of the primary malignancy are generally similarbeing helpful for further classification.

Hence, VPCT can non-invasively support and enhanceexisting diagnostic modalities and help the oncologist forcorrect diagnosis of cardiac masses.

Conflict of interest: None.

REFERENCES

1 Sparrow PJ, Kurian JB, Jones TR, et al. MR imaging of cardiac tumors.Radiographics 2005;25:1255–76

2 Bussani R, De-Giorgio F, Abbate A, et al. Cardiac metastases. J ClinPathol 2007;60:27–34

3 Chiles C, Woodard PK, Gutierrez FR, et al. Metastatic involvement of theheart and pericardium: CT and MR imaging. Radiographics2001;21:439–49

4 Klatt EC, Heitz DR. Cardiac metastases. Cancer 1990;65:1456–95 Dursun M, Sarvar S, Cekrezi B, et al. Cardiac metastasis from invasive

thymoma via the superior vena cava: cardiac MRI findings. CardiovascIntervent Radiol 2008;31:S209–12

6 Petersen CD, Robinson WA, Kurnick JE. Involvement of the heartand pericardium in the malignant lymphomas. Am J Med Sci 1976;272:161–5

7 Kim EY, Choe YH, Sung K, et al. Multidetector CT and MR imagingof cardiac tumors. Korean J Radiol 2009;10:164–75

8 Miyasaka Y, Barnes ME, Gersh BJ, et al. Secular trends in incidenceof atrial fibrillation in Olmsted County, Minnesota, 1980 to 2000, andimplications on the projections for future prevalence. Circulation2006;114:119–25

9 Falanga A, Marchetti M. Venous thromboembolism in the hematologicmalignancies. J Clin Oncol 2009;27:4848–57

10 Paraskevaidis IA, Michalakeas CA, Papadopoulos CH, et al. Cardiactumors. ISRN Oncol 2011;2011:208929

11 Gulati G, Sharma S, Kothari SS, et al. Comparison of echo and MRI in theimaging evaluation of intracardiac masses. Cardiovasc Intervent Radiol2004;27:459–69

12 Mulvagh SL, Rakowski H, Vannan MA, et al. American Society ofEchocardiography Consensus Statement on the Clinical Applications ofUltrasonic Contrast Agents in Echocardiography. J Am Soc Echocardiogr2008;21:1179–201

13 Platts DG, Fraser JF. Contrast echocardiography in critical care: echoes ofthe future? A review of the role of microsphere contrastechocardiography. Crit Care Resusc 2011;13:44–55

14 Matsumura M, Takamoto S, Kyo S, et al. Advantages of transesophagealcolor Doppler echocardiography in the diagnosis and surgical treatmentof cardiac masses. J Cardiol 1990;20:701–14

15 DePace NL, Soulen RL, Kotler MN, et al. Two dimensionalechocardiographic detection of intraatrial masses. Am J Cardiol1981;48:954–60

16 Hoffmann U, Globits S, Frank H. Cardiac and paracardiac masses.Current opinion on diagnostic evaluation by magnetic resonanceimaging. Eur Heart J 1998;19:553–63

17 Krombach GA, Saeed M, Higgins CB. Cardiac Masses. In: Higgins CB,de Roos A, eds. MRI and CT of the Cardiovascular System, Philadelphia,PA: Lippincott Williams & Wilkins, 2006:162–82

18 Hoey ET, Mankad K, Puppala S, et al. MRI and CT appearances ofcardiac tumours in adults. Clin Radiol 2009;64:1214–30

19 O’Donnell DH, Abbara S, Chaithiraphan V, et al. Cardiac tumors:optimal cardiac MR sequences and spectrum of imaging appearances.Am J Roentgenol 2009;193:377–87

20 Poustchi-Amin M, Gutierrez FR, Brown JJ, et al. Performingcardiac MR imaging: an overview. Magn Reson Imaging Clin N Am2003;11:1–18

21 Higgins CB. Acquired heart disease. In: Higgins CB, Hricak H, HelmsCA, eds. Magnetic resonance imaging of the body. New York, NY:Lippincott-Raven, 1997:409–60

22 Raj V, Alpendurada F, Christmas T, et al. Cardiovascularmagnetic resonance imaging in assessment of intracaval andintracardiac extension of renal cell carcinoma. J Thorac CardiovascSurg 2012;144:845–51

23 Rahbar K, Seifarth H, Schafers M, et al. Differentiation of malignantand benign cardiac tumors using 18F-FDG PET/CT. J Nucl Med2012;53:856–63

24 Maurer AH, Burshteyn M, Adler LP, et al. How to differentiate benignversus malignant cardiac and paracardiac 18F FDG uptake at oncologicPET/CT. Radiographics 2011;31:1287–305

25 Jeong DW, Choo KS, Baik SK, et al. Step-and-shoot prospectivelyECG-gated versus retrospectively ECG-gated with tube currentmodulation coronary CT angiography using the 128-slice MDCT:comparison of image quality and radiation dose. Acta Radiol2011;52:155–60

26 Spira D, Gerlach JD, Spira SM, et al. Effect of scan time on perfusionand flow extraction product (K-trans) measurements in lung cancerusing low-dose volume perfusion CT (VPCT). Acad Radiol 2012;19:78–83

27 Miles KA. Perfusion CT for the assessment of tumour vascularity: whichprotocol? Br J Radiol 2003;76:S36–42

28 Petralia G, Preda L, D’Andrea G, et al. CT perfusionin solid-body tumours. Part I: Technical issues. Radiol Med 2010;115:843–57

29 Miles KA, Charnsangavej C, Lee FT, et al. Application of CT inthe investigation of angiogenesis in oncology. Acad Radiol 2000;7:840–50

30 Ketelsen D, Horger M, Buchgeister M, et al. Estimation of radiationexposure of 128-slice 4D-perfusion CT for the assessment of tumorvascularity. Korean J Radiol 2010;11:547–52

31 Bamberg F, Hinkel R, Schwarz F, et al. Accuracy of dynamiccomputed tomography adenosine stress myocardial perfusionimaging in estimating myocardial blood flow at various degrees ofcoronary artery stenosis using a porcine animal model. Invest Radiol2012;47:71–7

8 M Schulze et al.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from

32 Wang X, Xue HD, Jin ZY, et al. Quantitative hepatic CTperfusion measurement: Comparison of Couinaud’s hepaticsegments with dual-source 128-slice CT. Eur J Radiol 2013;82:220–6

33 Ippolito D, Capraro C, Casiraghi A, et al. Quantitative assessment oftumour associated neovascularisation in patients with liver cirrhosis

and hepatocellular carcinoma: role of dynamic-CT perfusion imaging.Eur Radiol 2012;22:803–11

34 Beroukhim RS, Prakash A, Buechel ER, et al. Characterization of cardiactumors in children by cardiovascular magnetic resonance imaging:a multicenter experience. J Am Coll Cardiol 2011;58:1044–54

35 Smith HJ. Cardiac MR imaging. Acta Radiol 1999;40:1–22

Characterization of incidental cardiac masses in oncological patients 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

at Universitaet Tuebingen on July 26, 2013acr.sagepub.comDownloaded from