A

nmocritsr©

KH

1

vae(aHbobrp

1d

Joint Bone Spine 76 (2009) 474–480

Review

Single-photon emission computed tomography combined withcomputed tomography (SPECT/CT) in bone diseases

Dimitri Papathanassiou a,∗, Claire Bruna-Muraille a, Christelle Jouannaud b,Laurence Gagneux-Lemoussu c, Jean-Paul Eschard c, Jean-Claude Liehn a

a Service de médecine nucléaire, institut Jean-Godinot, 1, rue du Général-Koenig, BP 171, 51056 Reims cedex, Franceb Département d’oncologie médicale, institut Jean-Godinot, 1, rue du Général-Koenig, BP 171, 51056 Reims cedex, France

c Service de rhumatologie, hôpital Maison-Blanche, CHU de Reims, 45, rue Cognacq-Jay, 51092 Reims cedex, France

Accepted 23 January 2009Available online 2 October 2009

bstract

Radionuclide bone scanning was proven effective many years ago. Its main advantages are good sensitivity, limited radiation exposure, andoninvasiveness. However, increased radionuclide uptake by a lesion is not specific, and differentiating malignant from nonmalignant disordersay therefore be difficult. An additional structural imaging study is often needed to establish the final diagnosis. Furthermore, the limited resolution

f radionuclide bone scanning images does not allow accurate localization of the lesions. Single-photon emission computed tomography (SPECT)ombined with computed tomography (CT) provides both structural and functional information. SPECT/CT has been proven useful for interpretingadionuclide bone scan results in patients with bone malignancies, showing far better specificity than planar imaging or SPECT alone, most notablyn the evaluation of spinal abnormalities. SPECT/CT provides an accurate evaluation of the site of the lesions and also supplies other information

hat can be useful in nonmalignant conditions such as injuries, infections, and degenerative disease. Nevertheless, there are only a few publishedtudies on the usefulness of SPECT/CT in nonmalignant conditions. However, SPECT/CT is only starting to become available and may become aoutine investigation for a number of rheumatic disorders.

2009 Société francaise de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.

; Ben

s(

tSbionwm

eywords: Radionuclide bone scanning; Oncology; Musculoskeletal diseasesybrid imaging

. Introduction

Radionuclide bone scanning is used to diagnose or to evaluatearious malignant and nonmalignant bone diseases [1]. A keydvantage is high sensitivity: abnormalities become apparentarly and sensitivity is higher than with computed tomographyCT) or standard radiography. Other advantages are goodvailability, low cost, and the ability to image the entire body.owever, bone tissue binding of the tracers, which are usuallyisphosphonates labeled with technetium 99m, depends onsteoblast activity and on the bone remodeling rate. Therefore,

inding is not specific for a particular disease process. As aesult, radionuclide bone scanning findings must often be inter-reted in the light of information from structural imaging studies

∗ Corresponding author.E-mail address: d.papathanassiou@reims.fnclcc.fr (D. Papathanassiou).

psatsts

297-319X/$ – see front matter © 2009 Société francaise de rhumatologie. Publishedoi:10.1016/j.jbspin.2009.01.016

ign; Tomography; Emission-computed; Single-photon/computed tomography;

uch as radiography, CT, and magnetic resonance imagingMRI).

On planar images, the superimposition of anatomical struc-ures complicates image interpretation, most notably at the spine.ingle-photon emission computed tomography (SPECT) haseen developed over the last few years as a means of overcom-ng this difficulty. SPECT provides accurate data on the sitef the lesions, which may help to differentiate malignant fromonmalignant conditions. This may be important at the spine,here both metastases and nonmalignant conditions are com-on, particularly in older individuals [2]. High uptake by the

edicles or posterior vertebral body often indicates a metasta-is, whereas high uptake by the facet joints is usually due tononmalignant condition [3,4]. This improved localization of

he lesions contributes to increase the specificity of the imagingtudy and is useful for comparisons with other slice imagingechniques (CT and MRI). Furthermore, SPECT is more sen-itive than radionuclide bone scanning with planar imaging.

by Elsevier Masson SAS. All rights reserved.

nt Bo

T5troiina

uboct[

tadctsomrciSidi1

S

iSiScdcrtaDtoctsasfmwl

(tetsnf

gtp

2

manstTbicaailuiro

mi1iaawspwAtitao

3

3

D. Papathanassiou et al. / Joi

he number of detected spinal lesions may increase by 20 to0% [3,4] and improvements in sensitivity, specificity, nega-ive predictive value, and positive predictive value have beeneported [5]. In particular, SPECT improves the visualizationf lesions characterized by decreased uptake with no areas ofncreased uptake. However, the information obtained may provenadequate and specificity is only about 80% [6]. Thus, the diag-osis often requires structural imaging studies centered on thebnormalities shown by SPECT.

Image alignment software developed in recent years can besed to fuse images obtained by radionuclide bone scanning andy CT. The hybrid images thus obtained combine the advantagesf both imaging techniques. However, this method may be time-onsuming and raises a number of technical challenges such ashe need for identical patient position for both imaging studies7].

To circumvent these difficulties, a multimodality imagingechnique combining high-resolution structural images (CT)nd functional radionuclide scan images (SPECT) has beeneveloped. The SPECT/CT device comprises both a gammaamera for acquiring the SPECT images and a CT machinehat acquires slices of the region of interest. The table isimply moved between the camera and the CT machine, with-ut changing the position of the patient. This hybrid imagingodality that combines structural and functional images [8]

esembles fluoro-deoxyglucose positron emission tomographyoupled with CT (FDG-PET/CT), which has considerablymproved the imaging of patients with malignancies [9–11].PECT/CT is used to determine the exact site of tumors visual-

zed by radionuclide scanning, including neuroendocrine tumorsetected using radiolabeled octreotide, thyroid cancers usingodine 131, and neuroblastomas or pheochromocytomas using31I-meta-iodobenzylguanidine (MIBG) [7]. The usefulness ofPECT/CT in oncology has been established [12–14].

Whereas PET has well-standardized indications [15] set forthn recommendations that are updated regularly, the role forPECT/CT remains unclear, particularly relative to other imag-

ng studies such as MRI and PET. It is too early to say whetherPECT/CT will remain an ancillary method used only whenonventional radionuclide bone scanning fails to provide theiagnosis or whether precise indications for SPECT/CT in spe-ific clinical situations will emerge. These indications might beelated, for instance, to the fact that SPECT/CT supplies func-ional information (reminiscent of that supplied by MRI signalbnormalities) and structural information about cortical bone.ata are accumulating about the contribution of SPECT/CT to

he diagnosis of bone malignancies [12,16–21]. The advantagesf SPECT/CT are expected to prove useful also in nonmalignantonditions: the use of SPECT improves sensitivity comparedo planar imaging, the high spatial resolution of CT and thetructural information this modality provides allow an accuratessessment of lesion site, and the information on the shape andtructure of the abnormalities improves specificity. However,

ewer data are available regarding the use of SPECT/CT for non-alignant diseases than for malignancies. The final diagnosisas achieved in smaller proportions of patients with nonma-

ignant diseases (55% [22], 59% [23]) than with malignanciesmi

ne Spine 76 (2009) 474–480 475

75 to 94%). Image fusion may be useful (although less sohan in oncology patients) [20] even when the diagnosis is notstablished, for instance in helping to decide which diagnos-ic investigations should be performed next. In a prospectivetudy of 76 patients referred for radionuclide bone scanning foronmalignant conditions, 89% of patients were found to benefitrom SPECT/CT [23].

Here, we discuss the contribution of SPECT/CT to the investi-ation of bone diseases. Several examples are given and factorshat might influence the future role for SPECT/CT in clinicalractice are considered.

. SPECT/CT technique

Nuclear medicine societies have not yet published recom-endations about the SPECT/CT technique. We will describe

n example of a SPECT/CT protocol. In some indications, a pla-ar study may be useful at tracer injection (dynamic then static ortatic only). These planar images may supply valuable informa-ion, particularly regarding blood flow distribution in the tissues.he late-phase study starts with scanning acquisition of whole-ody anterior and posterior images about 3 hours after tracernjection. The centered planar images classically obtained as aomplement to the whole-body study are no longer indispens-ble. The whole-body images are examined to decide whetherny doubtful findings require SPECT/CT. If the whole-bodymages are normal or show lesions that are obviously nonma-ignant, SPECT/CT is not performed, unless the patient hasnexplained pain. Neither is SPECT/CT performed when themages are typical for metastases. Thus, SPECT/CT is chieflyeserved for patients in whom the whole-body scan shows oner more images of unclear significance.

SPECT is performed over about 45 cm (two investigationsay be done if needed), with 64 acquisitions, each usually last-

ng 15 seconds. The overall SPECT procedure may take from0 to 30 minutes depending on the machine. There is no need tonject an additional radiotracer dose. CT is performed immedi-tely after SPECT, with the patient in the same position. We usedual-detector-array scanner operated at 50 mAs and 130 kV,ith a slice thickness of 1 to 5 mm depending on the body

ite being investigated. These CT parameters are chosen by thehysician and affect the level of radiation exposure associatedith CT, which adds to the exposure related to the radiotracer.t present, contrast injection is rarely used for CT in this set-

ing (and is rarely useful for investigating bone diseases). Spiralmaging is generally used (and acquisition often requires lesshan 1 minute). It is worth noting, however, that the few currentlyvailable SPECT/CT machines are equipped with CT scannersf variable quality, which may bias study results.

. Indications

.1. Oncology

Malignant lesions may be difficult to differentiate from non-alignant conditions by bone scan, most notably when there

s a single hot spot (or a small number of spots). In oncology,

476 D. Papathanassiou et al. / Joint Bone Spine 76 (2009) 474–480

Table 1Main studies of the contribution of SPECT/CT to the evaluation of bone lesions in oncology patients.

Publication Number of patients Number of doubtful lesions by WBRBS and SPECT Results of SPECT/CT

Römer [16] 44 52 33 (63%) Benign15 (39%) Malignant

4 (8%) Indeterminate

Horger [18] 47 104 47 (45%) Benign41 (40%) Malignant16 (15%) Indeterminate

Utsunomiya [17] 45 82 40 (49%) Benign42 (51%) Malignant

Strobel [19] 37 42 31 (74%) Benign11 (26%) Malignant

Granier [24] 120 305 (69%) Benign84 (19%) Malignant51 (12%) Indeterminate

S ningb nar imt

Swaret

pitiocwSrtiasfionSbtili6a[

mb(s

ibd

3

bone scanning may visualize fractures. SPECT/CT may showa small lesion that was missed on radiographs or specify thelocation of a hot spot reflecting an abnormal reaction with-out detectable structural damage in a patient with a suspected

Fig. 1. The planar images suggest a nonmalignant condition but the sections

tudies of oncology patients in whom planar whole-body radionuclide bone scanone scanning with anteroposterior and posteroanterior views with or without plaomography; SPECT/CT: SPECT coupled with computed tomography.

PECT/CT is used to further evaluate a doubtful hot spot on thehole-body scan; the goal may be to confirm the hypothesis ofnonmalignant abnormality (Fig. S1; the supplementary mate-

ial associated with this article online), to obtain additionalvidence supporting a metastasis (Fig. S2), or to better determinehe location of the abnormality.

SPECT/CT is a recently introduced investigation on whichublished data are therefore scant. Table 1 reports the mainnformation available to date. In a study of patients who had his-ologically confirmed malignancies, 48 of 52 lesions classified asndeterminate by SPECT alone were classified as nonmalignantr malignant by SPECT/CT [16]. In another study, SPECT/CTlassified 85% of 104 lesions (in 47 patients), compared to 36%ith SPECT alone; however, follow-up data indicated thatPECT/CT yielded one false-positive and one false-negativeesult [18]. A retrospective study showed that a method similaro SPECT/CT improved the confidence with which physiciansnterpreted the imaging findings, compared to SPECT or CTlone [17]. In a prospective study of 37 patients with 42 focalpinal lesions, all lesions doubtful by SPECT alone were classi-ed by SPECT/CT, which ensured the correct diagnosis in 100%f cases, compared to 64% with whole-body radionuclide scan-ing and 86% with SPECT alone [19]. In patients with tumors,PECT/CT improved the confidence with which radionuclideone scans were interpreted, by improving the localization ofhe lesions, confirming the diagnosis suggested by the planarmages, or supplying or correcting the diagnosis [20]. Finally, theargest study to date, with 440 lesions and 6 months’ follow-upn 69 of the included patients, showed that SPECT/CT detected4% more lesions than did planar radionuclide bone scanningnd correctly classified over 88% of lesions and 95% of patients24].

The most extensively studied lesions by SPECT/CT are spinal

etastases [16–20,22,24] not only because these are common,

ut also because SPECT/CT is particularly helpful at the spineFig. S2). The greater accuracy of the structural informationupplied by SPECT/CT compared to SPECT alone translates

ibsfv

and SPECT alone showed doubtful lesions. WBRBS: whole-body radionuclideages centered on the abnormalities; SPECT: single-photon emission computed

nto improved specificity, in particular by helping to distinguishetween a periarticular lesion and an intraosseous lesion at aistance from a joint (Figs. 1–3).

.2. Traumatology

In patients whose radiographs are inconclusive, radionuclide

ndicate a metastasis. Head-and-neck cancer workup in a 55-year-old male withack pain. The whole-body scan (a, b) shows two hot spots on either side at T12uggesting facet joint osteoarthritis. On the axial sections (c: SPECT; d: SPECTused with CT; e: CT), the foci are seen to be located in the posterior part of theertebral body where anterior lysis is visible, suggesting a metastasis.

D. Papathanassiou et al. / Joint Bone Spine 76 (2009) 474–480 477

Fig. 2. The planar images suggest a malignancy but the sections indicateosteoarthritis. This 70-year-old female had a history of breast cancer 10 yearsearlier and was being evaluated for a suspected local recurrence. On the whole-b(l

fsdmtiptiSc

Fraoigfc

Fig. 4. Additional diagnostic information provided by sections in trauma-relateddisorders. This 48-year-old male was referred for suspected reflex sympatheticdystrophy syndrome of the right lower limb three weeks after completing aperiod of immobilization for a midtarsal sprain. No fractures were visible on theradiograph (a, b). Planar radionuclide bone scan images at the early phase (c) andlate phase (d, e) show an early increase in uptake and a focus of hyperactivity inthe midtarsal region, consistent with a sprain. However, the sections (f: SPECT;gls

liSa

ody scan (a, b), a hot spot at T8 suggests a metastasis. On the sagittal sectionsc: SPECT; d: SPECT fused with CT; e: CT), the hot spot matches degenerativeesions of the T7-T8 level.

atigue fracture. When radiographs are not obtained prior to bonecintigraphy, coupling with CT images may provide the finaliagnosis with no waste of time for the patient. Detailed infor-ation on the location of the abnormalities can contribute to

he diagnosis (Fig. 4). Furthermore, SPECT/CT may be helpfuln patients with postoperative or posttraumatic changes, whenrecise localization of a focus of residual hyperactivity or of

issue compromise adjacent to fixation material may providemportant clues. In a case-series study of 80 trauma patients,PECT/CT detected 96% more lesions than did planar radionu-lide bone scanning, increased the proportion of accurately

ig. 3. Planar images suggesting a malignancy are seen on the sections to beelated to benign lesions. Incapacitating back pain in a 78-year-old female withhistory of breast cancer more than 10 years earlier. Several hot spots are visiblen the whole-body scan (a, b), some of which are located at the spine, and theres a focus of decreased uptake at L1. The coronal sections (c and f: SPECT; d and: SPECT fused with CT; e and h: CT) show that the hot spots match vertebralractures at T7 and T12 that exhibit no evidence of malignancy. The axial sectionsentered on the low-activity L1 focus (i, j and k) indicate an angioma.

fiSt

3

sfatwfipaoi

3

rb

: SPECT fused with CT; h: CT) not only provide details on the location of theesions in the midtarsal region but also show a higher-uptake focus indicating amall fracture at the anteromedial part of the calcaneus.

ocalized lesions from 3 to 95%, and decreased the proportion ofndeterminate diagnoses from 61 to 7% [25]. More specifically,PECT/CT assisted in the identification of ligament or tendonvulsions, osteochondral lesions, posttraumatic osteoarthritis,ssures, fatigue fractures (Fig. 4, Fig. S3), and other fractures.pondylolysis may be a good candidate for SPECT/CT evalua-

ion [26].

.3. Osteoarticular infections

Radionuclide bone scanning has high sensitivity but lowpecificity for diagnosing infections. Coupled CT may showeatures that point to the diagnosis, such as cortical destruction,foreign body, or a sequestrum. In patients with a history of

rauma or surgery, determining the exact location of the hot spotithin the changes visualized by structural imaging may be use-

ul, in particular to guide a surgical procedure. Preliminary datandicate a substantial increase in specificity when SPECT is cou-led with CT [27]. Furthermore, when radiolabeled leukocytesre used as the tracer, SPECT/CT provides accurate informationn the site of cell accumulation and helps to differentiate bonenfection from soft tissue infection (Fig. S4) [28,29].

.4. Other indications

In patients with osteoarthritis, the many changes visible byadiography and CT can be correlated with the radionuclideone scanning data to confirm that any hot spots are due to

478 D. Papathanassiou et al. / Joint Bone Spine 76 (2009) 474–480

Table 2Potential contribution of SPECT/CT in nonmalignant bone conditions investigated by planar radionuclide bone scanning (RBS).

Indications Potential contribution of SPECT/CT

Fractures not visible on radiographs Localization of RBS abnormalitiesConfirmation of the diagnosis by CT if CT shows lesions not visible on radiographsDifferential diagnosis with joint diseases (e.g., osteoarthritis)

Suspected reflex sympathetic dystrophy syndrome Detection of a previously missed trauma-related lesion that explains the symptoms, with or withoutevidence of reflex sympathetic dystrophy syndrome

Vertebral fractures In doubtful cases, CT confirms the absence of signs of malignancy

Osteonecrosis Shows that a single side of the joint is affected (differentiation from other joint conditions)

Osteoarthritis CT confirms the diagnosisDetection of co-existent lesionsDifferentiation from malignant lesions

Inflammatory joint disease Evidence that the lesion involves the jointDifferentiation from osteoarthritis

Paget’s disease CT confirms the diagnosis when the RBS appearance is atypicalLocalization

Metabolic bone diseases Detection of a co-existing fractureInvestigation of vertebral fractures

Prostheses Localization of the abnormalityCorrelation with the radiographic findings (e.g., heterotopic ossifications)

Heterotopic ossifications Confirmation that the hot spots by RBS match the ossifications seen on radiographs

Infections Differential diagnosisLocalizationComparison of RBS to radiolabeled leukocyte scanning, both acquired with CT

Bnosis

tdtHfn

ffftocptp

4

4

hFi(d

hfauots

mpEic[tca

sdasa

enign tumors LocalizationCT confirms the diag

he degenerative disease. Osteoarthritis is not an indication foriagnostic scintigraphy. SPECT/CT may be useful to confirmhat a focal bone reaction is related to degenerative changes.owever, the main indication of SPECT/CT is differentiation

rom other causes of increased uptake (Fig. 2, Fig. S5), mostotably bone metastases.

The available data are not yet sufficient to determine the placeor SPECT/CT in other conditions such as osteonecrosis or painrom a joint prosthesis. In all likelihood, accurate localization ofoci of abnormal uptake and the addition of structural informa-ion improves specificity or allows refinement of the diagnosticr therapeutic strategy. However, the exact impact of SPECT/CTompared to current evaluations is unclear. Table 2 indicates theossible contribution of SPECT/CT to the diagnosis of the condi-ions most often evaluated by radionuclide bone scanning, whenlanar images fail to provide the diagnosis.

. SPECT/CT in everyday practice

.1. Advantages of hybrid imaging

SPECT/CT combines the advantages of both techniques: theigh spatial resolution of CT and the high sensitivity of SPECT.

urthermore, the morphological appearance of the lesion is often

mportant to confirm, to establish, or to correct the diagnosisosteolysis or sclerosis suggesting a malignancy, changes clearlyue to osteoarthritis or fractures, evidence of Paget’s disease,

ntSM

emangioma, posterior displacement of the posterior wall of aractured vertebra, associated soft tissue mass. . .) (Fig. 3). Thebsence of CT abnormalities at sites of increased radionuclideptake may suggest a malignancy, as the uptake abnormalitiesccur first [12]. On the other hand, CT may detect abnormali-ies (threatening spinal cord compression, fractures) not seen bycintigraphy.

CT may identify artifacts (although these are fairly uncom-on and often easily identified in bone scintigraphy) or

rovide useful information on rare or unusual findings [30].ven in the absence of artifacts, coupling the two techniques

ncreases diagnostic confidence [5,17,19,20,22]. Specificity isonsiderably higher with SPECT/CT than with SPECT alone12,18,20,21]. Furthermore, SPECT/CT may identify lesionshat are not seen by scintigraphy, such as osteolytic foci, andonsequently SPECT/CT is slightly more sensitive than SPECTlone [18].

Performing additional imaging investigations from the out-et may decrease the time needed to establish the finaliagnosis, by obviating the need for further tests. Thisdvantage may be particularly valuable in patients withuspected cancer, as a shorter time to diagnosis lessensnxiety and allows earlier treatment. In patients who still

eed other investigations, such as diagnostic CT or MRI,heir interpretation may benefit from accurate localization byPECT/CT of the focus of abnormal uptake. The need forRI may be recognized more rapidly, for instance when a

nt Bo

tb[

4

gsmmoiasm

cwirtircafr

cifS

4S

iubmfpsM

g

ii

4

pk

9

abSdsteni

bvbwabFtOpetp

dotbat

5

ifiaSmractipwistations reviewed herein and potential advantages are borne inmind.

D. Papathanassiou et al. / Joi

hreatening spinal lesion is suspected. In patients requiringiopsies, SPECT/CT has been found useful as a guiding tool31].

.2. Practical organization and availability

Not all nuclear medicine departments are equipped with aamma camera coupled with a spiral CT machine. However,ince the introduction of SPECT/CT machines on the market,ost departments have been incorporating the purchase of such aachine into their equipment replacement plans, and the number

f departments that own SPECT/CT machines has been increas-ng at a fast pace since 2006. In France, it has been estimated thatbout 20% of gamma cameras are equipped with a CT machineimilar to the one described herein and that over 40% of nuclearedicine departments own SPECT/CT machines.Optimal utilization of SPECT/CT machines may be diffi-

ult to schedule, as the need for SPECT/CT is determined onlyhen the planar radionuclide scans, and occasionally the SPECT

mages, prove inadequate. Thus, the number of patients who willequire SPECT/CT is difficult to predict. SPECT/CT increaseshe total time needed to investigate each patient. Although CTmage acquisition requires only about 1 minute, SPECT usuallyequires 15 to 30 minutes and the patients must therefore beapable of keeping still during this additional time. SPECT/CTlso increases the image processing and reading times. There-ore, SPECT/CT cannot be performed in all patients referred foradionuclide bone scanning.

In France, the universal health insurance agency has set theost of whole-body radionuclide bone scanning at 180 Euros;f early-phase images are acquired, the cost is 269 Euros. Per-orming SPECT adds 133 Euros, whereas CT can be coupled toPECT at no additional cost.

.3. Limitations of the diagnostic performance of bonePECT/CT

Although hybrid imaging is an undeniable improvement,t does not consistently provide the diagnosis. For instance,ptake abnormalities without detectable CT abnormalities maye of unclear significance. SPECT/CT may show CT abnor-alities that are difficult to interpret or located outside the

ocus of abnormal radionuclide uptake. In this situation, theatient may require further imaging studies such as adapted CTcanning with thinner slices and perhaps contrast injection, or

RI.The technical protocol used for CT coupled with SPECT is

enerally different from the protocol for diagnostic CT.Furthermore, given the rapid development of SPECT/CT, the

nterpretation of the coupled images can be expected to improven the near future.

.4. Radiation exposure

Adding CT to SPECT increases the radiation dose to theatient. Assuming an injected dose of about 10 MBq perilogram of body weight, i.e., about 700 MBq (19 mCi) of

C

ne Spine 76 (2009) 474–480 479

9mTc-bisphosphonate for a 70-kg individual, the exposure isbout 4 mSv (2.4 to 5.5 mSv in general) during radionuclideone scanning with or without SPECT. The CT component ofPECT/CT exposes to a lower dose (50 mAs and 130 kV) thano other diagnostic CT procedures, with variations across bodyites, from less than 0.1 mSv for the extremities to a few mSv forhe torso (when covering the entire gamma camera field). Whenxamining the feet by SPECT/CT, the CT component does nototiceably increase the exposure compared to the radiotracernjection.

The CT field of view can be limited to the site that is abnormaly radionuclide bone scanning [16], whereas the SPECT field ofiew is invariable at about 40 cm. Limited field-of-view CT maye appropriate in some cases, such as nonmalignant conditions,here there is less risk of losing useful information (CT appear-

nce) about an abnormality that is located within the SPECT fieldut is not visualized clearly on the planar radionuclide scans.urthermore, CT slices need not be acquired routinely; instead,

he need for CT can be determined based on the SPECT findings.ne benefit from this strategy is decreased radiation exposure toatients in whom normal SPECT findings are anticipated. How-ver, the SPECT images must be examined promptly to limithe time during which the patient must remain immobile, and inractice this strategy is rarely used.

The additional radiation exposure should be considered wheneciding whether to add CT. This decision depends not onlyn the information that CT is expected to provide, but also onhe age and sex of the patient, medical setting, and body siteeing investigated. In oncology, the benefits expected from thedditional imaging often far outweigh the risks associated withhe additional radiation exposure.

. Conclusion

Hybrid SPECT/CT improves diagnostic confidence whennterpreting equivocal planar images, improves average speci-city compared to radionuclide bone scanning, and probablylso improves sensitivity (to a lesser extent). More specifically,PECT/CT is useful for detecting metastases of osteophilicalignancies, most notably at the spine. However, the exact

ole for SPECT/CT relative to MRI and CT in patients evalu-ted for bone metastases is still under investigation. SPECT/CTan also provide useful information on nonmalignant condi-ions, although the available data is still insufficient to assessts usefulness in each potential indication or to define itsosition as a diagnostic tool in rheumatology. These pointsill probably be clarified as the availability of SPECT/CT

ncreases. When used with discernment, SPECT/CT canupply valuable data in selected patients, provided the limi-

onflicts of interest

The authors have no conflicts of interest to declare.

4 int Bo

A

a1

R

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

[

80 D. Papathanassiou et al. / Jo

ppendix A. Supplementary material

Supplementary material (Fig. S1–S5) associated with thisrticle can be found at http://www.sciencedirect.com, at doi:0.1016/j.jbspin.2009.01.016.

eferences

[1] Paycha F, Richard B. Exploration scintigraphique du squelette. Encycl MedChir 2002:30-480-A-10.

[2] Even-Sapir E, Martin RH, Barnes DC, et al. Role of SPECT in differen-tiating malignant from benign lesions in the lower thoracic and lumbarvertebrae. Radiology 1993;187:193–8.

[3] Gates GF. SPECT bone scanning of the spine. Semin Nucl Med1998;28:78–94.

[4] Reinartz P, Schaffeldt J, Sabri O, et al. Benign versus malignant osseouslesions in the lumbar vertebrae: differentiation by means of bone SPET.Eur J Nucl Med 2000;27:721–6.

[5] Even-Sapir E. Imaging of malignant bone involvement by morphologic,scintigraphic, and hybrid modalities. J Nucl Med 2005;46:1356–67.

[6] Even-Sapir E, Metser U, Mishani E, et al. The detection of bone metas-tases in patients with high-risk prostate cancer: 99mTc-MDP planar bonescintigraphy, single- and multi-field-of-view SPECT, 18F-fluoride PET,and 18F-fluoride PET/CT. J Nucl Med 2006;47:287–97.

[7] Keidar Z, Israel O, Krausz Y. SPECT/CT in tumor imaging: technicalaspects and clinical applications. Semin Nucl Med 2003;33:205–18.

[8] Papathanassiou D, Liehn JC. The growing development of mul-timodality imaging in oncology. Crit Rev Oncol Hematol 2008,doi:10.1016/j.critrevonc.2008.10.006.

[9] von Schulthess GK, Steinert HC, Hany TF. Integrated PET/CT: currentapplications and future directions. Radiology 2006;238:405–22.

10] Czernin J, Allen-Auerbach M, Schelbert HR. Improvements in cancer stag-ing with PET/CT: literature-based evidence as of September 2006. J NuclMed 2007;48(Suppl. 1):78S–88S.

11] Weber WA, Figlin R. Monitoring cancer treatment with PET/CT: does itmake a difference? J Nucl Med 2007;48(Suppl. 1):36S–44S.

12] Horger M, Bares R. The role of single-photon emission computed tomog-raphy/computed tomography in benign and malignant bone disease. SeminNucl Med 2006;36:286–94.

13] Krausz Y, Israel O. Single-photon emission computed tomography/computed tomography in endocrinology. Semin Nucl Med 2006;36:267–74.

14] Husarik DB, Steinert HC. Single-photon emission computed tomogra-phy/computed tomography for sentinel node mapping in breast cancer.Semin Nucl Med 2007;37:29–33.

15] Duet M, Pouchot J, Liote F, et al. Role for positron emission tomographyin skeletal diseases. Joint Bone Spine 2007;74:14–23.

[

ne Spine 76 (2009) 474–480

16] Romer W, Nomayr A, Uder M, et al. SPECT-guided CT for evaluatingfoci of increased bone metabolism classified as indeterminate on SPECTin cancer patients. J Nucl Med 2006;47:1102–6.

17] Utsunomiya D, Shiraishi S, Imuta M, et al. Added value of SPECT/CTfusion in assessing suspected bone metastasis: comparison with scintig-raphy alone and nonfused scintigraphy and CT. Radiology 2006;238:264–71.

18] Horger M, Eschmann SM, Pfannenberg C, et al. Evaluation of combinedtransmission and emission tomography for classification of skeletal lesions.AJR Am J Roentgenol 2004;183:655–61.

19] Strobel K, Burger C, Seifert B, et al. Characterization of focal bonelesions in the axial skeleton: performance of planar bone scintigraphy com-pared with SPECT and SPECT fused with CT. AJR Am J Roentgenol2007;188:W467–74.

20] Netter F, Journo A, Mayer JC, et al. Apport de la TEMP-TDM en complé-ment de la scintigraphie osseuse planaire dans la pratique courante duservice de médecine nucléaire. Med Nucl 2008;32:76–84.

21] Granier P, Mourad M. Performance de la scintigraphie osseuse planaireassociée à la TEMP-TDM en cancérologie. Med Nucl 2008;32:201.

22] Papathanassiou D, Bruna C, Cuif-Job A, et al. Bone SPECT/CT in dailypractice. Eur J Nucl Med Mol Imaging 2007;34:S176.

23] Even-Sapir E, Flusser G, Lerman H, et al. SPECT/multislice low-dose CT:a clinically relevant constituent in the imaging algorithm of nononcologicpatients referred for bone scintigraphy. J Nucl Med 2007;48:319–24.

24] Granier P, Mourad M. Évaluation par la TEMP–TDM des lésions classéesindéterminées en scintigraphie osseuse chez les patients de cancérologie.Med Nucl 2008;32:265–72.

25] Granier P, Mourad M. Évaluation de l’imagerie hybride TEMP–TDM dansl’exploration des lésions traumatiques ou microtraumatiques. Med Nucl2007;31:430.

26] Slosman DO, Martin JB, Willi JP. La tomographie d’émission monopho-tonique couplée à la tomodensitométrie : applications en pathologieosseuse. Med Nucl 2006;30:301–8.

27] Horger M, Eschmann SM, Pfannenberg C, et al. Added value of SPECT/CTin patients suspected of having bone infection: preliminary results. ArchOrthop Trauma Surg 2007;127:211–21.

28] Horger M, Eschmann SM, Pfannenberg C, et al. The value of SPECT/CTin chronic osteomyelitis. Eur J Nucl Med Mol Imaging 2003;30:1665–73.

29] Filippi L, Schillaci O. Usefulness of hybrid SPECT/CT in 99mTc-HMPAO-labeled leukocyte scintigraphy for bone and joint infections. J Nucl Med2006;47:1908–13.

30] Domange-Testard A, Papathanassiou D, Meneroux B, et al. SPECT-CT

images of an ocular coralline hydroxyapatite implant visible on bonescintigraphy. Clin Nucl Med 2007;32:132–4.

31] O’Connor MK, Kemp BJ. Single-photon emission computed tomogra-phy/computed tomography: basic instrumentation and innovations. SeminNucl Med 2006;36:258–66.