ARTHRITIS & RHEUMATISM
Vol. 46, No. 11, November 2002, pp 2964–2967
© 2002, American College of Rheumatology
Fast Spin Echo–T2-Weighted Sequences With Fat Saturation in
Dactylitis of Spondylarthritis
No Evidence of Entheseal Involvement of the Flexor Digitorum Tendons
Ignazio Olivieri,1Carlo Salvarani,2Fabrizio Cantini,3Enrico Scarano,4Angela Padula,1
Laura Niccoli,3Giovanni Ciancio,1and Libero Barozzi5
Objective. To establish by means of fast spin echo
(FSE)–T2-weighted sequences with fat saturation if
enthesitis of the flexor digitorum superficialis and pro-
fundus tendons is the primary lesion in spondylarthritis
(SpA) finger dactylitis.
Methods. Eleven dactylitic fingers and their cor-
responding normal, contralateral fingers, belonging to 6
patients who met the Amor criteria for SpA, were
studied by FSE–T2-weighted sequences with fat satura-
Results. All dactylitic fingers showed moderate or
severe fluid collection in the flexor tendon synovial
sheaths. Involvement of the joint cavity was simulta-
neously present in at least one joint in 3 (27.3%) of the
11 fingers. A mild to moderate peritendinous soft tissue
edema was observed in 5 (45.5%) of the 11 affected
fingers. In no dactylitic finger was bone edema observed
near the insertions of the flexor digitorum superficialis
or profundus tendons or in other sites of the phalanges.
No lesions were observed in the 11 contralateral, clini-
cally normal fingers.
Conclusion. In SpA dactylitis there is no evidence
of enthesitis of the flexor digitorum tendons and joint
Dactylitis represents a typical feature of psoriatic
arthritis (PsA) (1) and spondylarthritis (SpA) (2) and
may occasionally prevail for a long time as the only
clinical manifestation (3). Flexor tenosynovitis is the
responsible lesion for the “sausage-shaped” aspect in
both finger dactylitis and toe dactylitis (4–9). Concom-
itant joint involvement is possible and has been found in
12.5–62.5% of cases (4–7).
Recently, McGonagle and colleagues demon-
strated, by using fat-suppressed magnetic resonance
imaging (MRI), that enthesitis is characterized by bone
marrow edema adjacent to the enthesis (10). In those
authors’ opinion, enthesitis is the primary lesion in SpA,
and synovitis of the various structures (joint, tendon, and
bursa) represents a secondary phenomenon due to the
release of proinflammatory cytokines from the inflamed
entheses (11). In a recent editorial, the same group
suggested that flexor tenosynovitis of dactylitis is also
due to enthesitis as a consequence of the diffusion of
cytokines along the tenosynovial sheaths (12).
The aim of this study was to evaluate the inser-
tions of the flexor and extensor digitorum tendons in
finger dactylitis by using fast spin echo (FSE)–T2-
weighted sequences with fat saturation.
PATIENTS AND METHODS
All consecutive patients who had finger dactylitis and
who met the Amor criteria (2) for classification of the entire
group of spondylarthropathies, and who were seen in our
centers (Potenza, Prato, and Reggio Emilia) during a 1-month
period, were considered suitable candidates for the study. Only
“sausage-like” fingers, of which the contralateral digit was
Supported by a grant from the Government of Basilicata
(Lucania) Region of Italy.
1Ignazio Olivieri, MD, Angela Padula, MD, Giovanni Cian-
cio, MD: San Carlo Hospital, Potenza and Madonna delle Grazie
Hospital, Matera, Italy;
Maria Nuova, Reggio Emilia, Italy;
Niccoli, MD: Prato Hospital, Prato, Italy;4Enrico Scarano, MD: San
Carlo Hospital, Potenza, Italy;
Malpighi Hospital, Bologna, Italy.
Address correspondence and reprint requests to Ignazio
Olivieri, MD, Rheumatology Department of Lucania, San Carlo
Hospital, Contrada Macchia Romana, 85100 Potenza, Italy. E-mail:
Submitted for publication March 22, 2002; accepted in revised
form August 8, 2002.
2Carlo Salvarani, MD: Arcispedale Santa
3Fabrizio Cantini, MD, Laura
5Libero Barozzi, MD: Sant’Orsola-
normal (no history of joint or tendon symptoms, and normal
appearance and absence of pain at the time of the study), were
studied. Eleven dactylitic fingers and their corresponding
normal, contralateral fingers belonging to 6 patients (3 female
and 3 male; median age 48.8 years, range 30–61 years) were
examined. All patients had PsA with a median disease duration
of 4.1 years (range 1–8 years).
MRI scanning was performed using a 1.5-T supercon-
ductive magnet system (SIGNAMR; GE Medical Systems,
Milwaukee, WI). Both hands, joined in the “prayer position,”
divided by a foam pad, and immobilized with tape were
positioned in the center of a 17-cm bore transmit–receive
extremity coil. Pulse sequences included axial spin echo–T1-
weighted sequences (540-ms repetition time, 14-ms echo time,
and 2 excitations), axial and sagittal FSE–T2-weighted se-
quences with fat saturation (3,500-ms repetition time, 60–
70-ms echo time, and 3 excitations), and sagittal gradient echo
(GRE)–T2-weighted 3-dimensional (3D) sequences (24-ms
repetition time, 6.6-ms echo time, and 2 excitations). The axial
section was 4–5 mm thick, and the sagittal section was 3–4 mm
thick; both had an intersection gap of 0.6–1 mm. The field of
view was 16 cm ? 12 cm and the matrix size was 256 cm ? 224
cm or 512 cm ? 224 cm.
Scan images were examined by 1 of 2 radiologists (ES
or LB) who were blinded to the physical examination results.
The presence of bright signal within the tendon sheath and
joint cavity on FSE–T2-weighted sequences with or without fat
saturation was considered as evidence of synovial membrane
involvement. We did not use intravenous contrast to differen-
tiate fluid from synovitis, since this study focused on possible
enthesis involvement. Soft tissue subcutaneous edema was
recorded on the same sequences. Bone marrow edema adja-
cent to the flexor and extensor tendon insertions was recorded
on FSE–T2-weighted and GRE–T2-weighted 3D sequences.
Both the flexor digitorum superficialis and the profundus
insertions into the anterior surface of the middle phalanx and
palmar surface of the base of distal phalanx were examined.
The insertions of the extensor digitorum tendons were also
A semiquantitative scale was used to evaluate the
severity of the lesions. The amount of fluid in the tenosynovial
sheaths and the joint cavity was graded as follows: 0 ? absence
of fluid, 1 ? fluid visible, 2 ? moderate accumulation of fluid,
and 3 ? distension of the sheaths or joint capsule. Soft tissue
subcutaneous edema was graded as follows: 0 ? absence of
edema, 1 ? mild, 2 ? moderate, and 3 ? severe. Bone edema
was graded as follows: 0 ? absence of edema, 1 ? mild, 2 ?
edema involving at least one-third of the phalanx, and 3 ?
edema involving most of the phalanx.
MRI results on the 11 dactylitic fingers studied
are shown in Table 1. Flexor tenosynovitis (grade 2 or 3)
was present in all dactylitic fingers. Joint effusion was
simultaneously present in at least one joint in 3 (27.3%)
of the 11 dactylitic fingers. A mild or moderate subcu-
taneous edema (Figure 1) was observed in 5 affected
fingers (45.5%). In no dactylitic fingers was bone edema
observed around the insertions of the flexor and exten-
sor tendons and in other sites of the phalanges (Figure
2). No lesions were observed in the 11 contralateral,
clinically normal fingers.
The results of the present study confirm that SpA
dactylitis is due to flexor tenosynovitis, and that enlarge-
ment of the finger joint capsule does not seem to be an
indispensable element for the presence of the “sausage-
Magnetic resonance imaging results on the 11 dactylitic fingers*
tenosynovitis† Joint synovitis†
MCP 1, PIP 1, DIP 1
MCP 1, PIP 1
* R ? right; L ? left; MCP ? metacarpophalangeal joints; PIP ? proximal interphalangeal joints; DIP ?
distal interphalangeal joints.
† 0 ? absence of fluid, 1 ? fluid visible, 2 ? moderate accumulation, 3 ? distension of the sheaths or joint
‡ 0 ? absence of edema, 1 ? mild, 2 ? moderate, 3 ? severe.
§ 0 ? absence of edema, 1 ? mild, 2 ? edema involving at least one-third of the phalanx, 3 ? edema
involving the majority of the phalanx.
FSE–T2-WEIGHTED SEQUENCES WITH FAT SATURATION IN SpA DACTYLITIS 2965
shaped” aspect (4–7). We observed the presence of joint
synovitis in 27.3% of dactylitic fingers. In our 2 previous
studies on MRI in dactylitis, we observed joint involve-
Figure 1. Axial spin echo–T1-weighted image (A) and fast spin echo–
T2-weighted image with fat saturation (B), showing fluid/synovitis in
the flexor synovial sheaths (open arrows) and subcutaneous edema
extending all around the circumference (solid arrows).
Figure 2. Sagittal gradient echo–T2-weighted (A) and fast spin echo–
T2-weighted image with fat saturation (B), showing fluid/synovitis in
the synovial sheaths (solid arrows) and normal flexor entheses and
adjacent bone (open arrows).
2966 OLIVIERI ET AL
ment in 12.5% of the 24 digits studied (4,5). Higher Download full-text
frequencies (52% and 62.5%) were found in 2 other
studies in which only ultrasound was performed (6,7).
In the present study we have paid special atten-
tion to the insertions of the flexor and extensor digito-
rum tendons. McGonagle et al considered enthesitis the
primary lesion in every type of peripheral manifestation
of SpA, that is, joint synovitis, bursitis, and tenosynovitis
(11). In those authors’ opinion, flexor tenosynovitis of
dactylitis is due to enthesitis as a consequence of the
diffusion of cytokines along the tenosynovial sheaths
(12). Although this mechanism may explain the onset of
articular synovitis, it would appear to be a less probable
explanation to support the impressive tenosynovitis
present in dactylitis (4–7). The entheses of the flexor
digitorum superficialis and profundus are very thin. In
contrast, tenosynovitis of dactylitis extends along the
entire course of the digital synovial sheaths, and when
the synovial sheaths of a finger communicate with the
ulnar palmocarpal sheaths, the sausage swelling also
extends into the palm of the hand (8,9). We used
FSE–T2-weighted sequences with fat saturation to show
the bone edema adjacent to the tendon insertion typical
of enthesitis of SpA (10). We did not find bone edema in
any dactylitic fingers around the insertions of both the
extensor or the flexor digitorum tendons or in other sites
of the phalanges. However, it should be noted that we
could have overlooked some minor bone edema
changes, since slice thickness was between 4 mm and 5
mm on axial section and 3–4 mm on sagittal sections,
with a gap of 0.6–1 mm.
Unlike our previous MRI study on finger dacty-
litis (4), we observed a mild or moderate edema in
peritendinous soft tissues in 5 (45.5%) of the 11 dacty-
litic fingers. We were not surprised, however, since we
observed a similar extent of edema in 2 of 12 dactylitic
toes in our second study on dactylitis (5). In 2 of the 5
dactylitic fingers in the present study, the edema also
extended to the dorsum of the fingers. The pathogenetic
mechanism of this edema is unclear and can probably be
ascribed to an increase in capillary permeability due to
flexor tenosynovitis and/or to an altered lymphatic drain-
age. It appears similar to the inflammatory swelling with
pitting edema of the hand and foot dorsum observed in
various inflammatory rheumatic conditions (13), includ-
ing late-onset SpA (14) and PsA (15). In all these
conditions, MRI has demonstrated the presence of a
strenuous extensor tenosynovitis that probably caused
the subcutaneous edema as a consequence of altered
In conclusion, the present study confirms that
dactylitis is due to flexor tenosynovitis, and suggests that
enthesitis of the flexor digitorum tendon and joint
capsule has no important role in the development of
SpA finger dactylitis.
1. Gladmann DD. Psoriatic arthritis. In: Khan MA, editor. Ankylos-
ing spondylitis and related spondyloarthropathies. Spine: state of
the art review. Philadelphia: Hanley and Belfus; 1990. p. 637–56.
2. Amor B, Dougados M, Mijiyawa M. Crite `res de classification des
spondylarthropathies. Rev Rum 1990;57:85–9.
3. Salvarani C, Cantini F, Olivieri I, Macchioni P, Niccoli L, Padula
A, et al. Isolated peripheral enthesitis and/or dactylitis: a subset of
psoriatic arthritis. J Rheumatol 1997;24:1106–10.
4. Olivieri I, Barozzi L, Favaro L, Pierro A, De Matteis M, Borghi C,
et al. Dactylitis in patients with seronegative spondylarthropathy:
assessment by ultrasonography and magnetic resonance imaging.
Arthritis Rheum 1996;39:1524–8.
5. Olivieri I, Barozzi L, Pierro A, De Matteis M, Padula A, Pavlica P.
Toe dactylitis in patients with spondylarthropathy: assessment by
magnetic resonance imaging. J Rheumatol 1997;24:926–30.
6. Kane D, Greaney T, Bresnihan B, Gibney R, Fitzgerald O.
Ultrasonography in the diagnosis and management of psoriatic
dactylitis. J Rheumatol 1999;26:1746–51.
7. Wakefield RJ, Emery P, Veale D. Ultrasonography and psoriatic
arthritis [letter]. J Rheumatol 2000;27:1564.
8. Olivieri I, Favaro L, Pierro A, Frisoni M, Ferri S, Barozzi L, et al.
Dactylitis also involving the synovial sheaths in the palm of the
hand. Ann Rheum Dis 1994;53:783–4.
9. Padula A, Olivieri I, Barozzi L, Salvarani C, Cantini F, De Matteis
M, et al. Dactylitis also involving the synovial sheaths in the palm
of the hand: two more cases studied by magnetic resonance
imaging. Ann Rheum Dis 1998;57:61–2.
10. McGonagle D, Gibbon W, O’Connor P, Green M, Pease C, Emery
P. Characteristic magnetic resonance imaging entheseal changes
of knee synovitis in spondylarthropathy. Arthritis Rheum 1998;41:
11. McGonagle D, Gibbon W, Emery P. Classification of inflamma-
tory arthritis by enthesitis. Lancet 1998;352:1137–40.
12. McGonagle D, Pease C, Marzo-Ortega H, O’Connor P, Emery P.
The case for classification of polymyalgia rheumatica and remit-
ting seronegative symmetrical synovitis with pitting edema as
primarily capsular/entheseal based pathologies. J Rheumatol 2000;
13. Olivieri I, Salvarani C, Cantini F. RS3PE syndrome: an overview.
Clin Exp Rheumatol 2000;18 Suppl 20:53–5.
14. Olivieri I, Padula A, Pierro A, Favaro L, Oranges GS, Ferri S. Late
onset undifferentiated seronegative spondylarthropathy. J Rheu-
15. Cantini F, Salvarani C, Olivieri I, Macchioni L, Niccoli L, Padula
A, et al. Distal extremity swelling with pitting edema in psoriatic
arthritis: a case control study. Clin Exp Rheumatol 2001;19:291–6.
FSE–T2-WEIGHTED SEQUENCES WITH FAT SATURATION IN SpA DACTYLITIS2967