SR data allowed revealing the characteristic signs of PsA symmetric polyarthritis variant (n = 15) and mutilans (osteolitic variant) form (n = 11) in wrists and hands: irregular narrowing of the joint spaces due to ankylosis,
erosions of the articular surfaces,
bony proliferation in the form of ossification in the interphalangeal ligaments and enthesophites.
Arthritis mutilans form was represented mostly by osteolysis with severe damages of bones surfaces.
High spatial resolution and wide range of CBCT images post-processing allowed identifying and determining the precise localization of bone structure pathological remodeling areas and enthesophites which size was even less than 1 mm.
Such small changes were not visualized reliably with SR.
CBCT images of the wrists and hands were distinguished by high spatial resolution,
optimal signal-to-noise ratio,
uniform accuracy and dynamic range grayscale,
which allowed estimating not only of bone structure,
but dense soft tissue formations as well: muscles,
ligaments and tendons (Fig.
1,
a–c).
As an example of the CBCT application in patients with PsA two clinical observations are presented.
Patient D.,
39 years old with PsA,
symmetric polyarthritis variant,
without widespread manifestations.
Activity 1.
Enthesopathy.
Limited psoriasis vulgaris.
Upon admission to the hospital complained of pain in the right knee joint during physical activity,
stiffness in the knee,
ankle and hands and wrists joints,
right hand DMPJ deformation,
recurring pain in the sacrum.
Psoriasis duration was within 8 years.
Pain in the right knee disturbs during last 9 years.
Arthrocentesis with removal of fluid regarding recurrent synovitis was performed 3 years ago.
Last 1.5 years the patient notes a progressive deformity of the right wrist distal IFJ,
increased pain in the right sacrum and both ankles.
Several courses of non-steroidal anti-inflammatory drugs have been provided without any significant effect.
The patient`s father suffered from psoriasis vulgaris.
According to the laboratory data rheumatoid factor and cyclic citrullinated peptide (CCP) antibody test were negative; erythrocyte sedimentation rate (ESR) was 8 mm/hour; C-reactive protein – 2.5 mg/L.
SR data allowed revealing the characteristic signs of PsA symmetric polyarthritis variant in wrists and hands with irregular narrowing of the joint spaces due to ankylosis,
articular surfaces erosions and deformities mostly in wrist joints.
During CBCT of hands and wrists of the patient the additional information was obtained.
It became possible to identify and clarify the spatial arrangement of erosions,
cysts and bony proliferation signs in the form of ossification in the interphalangeal ligaments even the smallest ones by its size (less than 1 mm),
and to assess the soft tissue condition as well.
It should also be noted that the number of detected erosions and cysts was almost 2,3 times higher with CBCT than with SR.
On the CBCT images the signs of calcification in the tendons attachment of the deep flexor muscles of the right hand I–II fingers and the I finger of the left hand were determined.
These changes were not visualized reliably on SR.
CBCT with its post processing capabilities enabled to clarify the relationships between the articular surfaces at the level of the wrist joints: signs of ankylosis were visualized between lunate and capitate,
trapezoid and trapezium,
capitate and navicular bones.
In all the other wrist joints convincing signs of ankylosis were absent (Fig.
2,
a–f).
Simultaneously the data proves that SR did not allow to visualize the signs of articular surfaces ankylosauria at that level.
After 10 months due to worsening of the joint syndrome CBCT exam was performed again.
While comparing the obtained results with the results of previous SR and CBCT studies a higher intensity of characteristic signs of PsA was marked.
For example,
the number of identified erosions and cysts increased up to 24 %.
Patient K.,
48 years old with PsA,
arthritis mutilans (osteolitic variant).
There were complains of the right wrist joints,
bilateral MCPJ and DMFJ pain and swelling,
limitation of movement in these joints as well.
Manifestation of psoriasis was diagnosed 14 years ago.
Over the past 5 years the patient was followed up by the rheumatologist with pain and swelling of the hands and wrists joints.
Anti-inflammatory therapy (Piascledine) courses during the month annually were conducted without any positive effect.
The admission to the hospital was due to appearance of sharp movements' restriction and pain in the wrists and hands joints.
According to the laboratory data rheumatoid factor and cyclic citrullinated peptide (CCP) antibody test were negative,
erythrocyte sedimentation rate (ESR) – 19 mm/hour,
C-reactive protein 4.5 mg/L.
CBCT data allowed revealing the characteristic signs of PsA arthritis mutilans form in wrists and hands with osteolysis of the IV–V distal phalanx bases with the «pencil-in-cap» deformities,
articular surfaces deformation and irregular narrowing of the IV–V DMPJ spaces of the left hand due to ankylosis,
bone proliferation in the form of ossification in the interphalangeal ligaments and enthesophites were revealed mostly in hands joints (Fig.
3,
a–e).
During CBCT of the hands and wrists compared to the SR the additional information was obtained.
Thanks to CBCT post processing capabilities it became possible to identify and clarify the relationships between articular surfaces in the IV–V DMPJ: signs of ankylosis were absent at the V DMPJ,
but were visualized reliably at the center of the IV DMPJ space.
The data of SR did not allow excluding the signs of articular surfaces ankylosauria at the level (Fig.
4,
a–d).
A standardized protocol for the description of hand and wrist CBCT in patients with PsA was developed and tabulated (See the Table 1) for the purpose of data unification,
as well as,
for process optimization of the general or quantitative count of the detected changes,
according to any of the usual methods for PsA joint-change assessment.
Information about hand and wrist changes in PsA obtained in the course of post-processing using sequential analysis of cross-scans and multiplanar reconstructions is recorded in the standardized protocol (erosion and narrowing are marked with scores (from 0 to 5),
while the remainder are marked with ‘+’ or ‘‒’ signs).
Changes of metacarpal bones,
distal finger phalanges,
and the CMCJ,
MCPJ and IPJ were marked in the table with a hyphen and denoted according to their sequence numbers.
Subject to clinicians’ needs,
standardized protocol data can be used not only to indicate the radiological signs of the pathologic process but also to calculate comparable scores both in respect of selected general or quantitative methods of assessing PsA-caused changes in the joint,
by summing the scores of the items required.
The data obtained from CBCT hand and wrist scans of PsA patients and recorded according to the standardized protocol are more readily visualized,
and this substantially simplifies comparison of cone-beam study results,
which were conducted in dynamics for assessment of the response to the treatment being used.
Regardless of the disease form and variant in all the patients there was a significant advantage of CBCT in the assessment of hands and wrists bones and joints changes.
The number of additionally detected proliferative and osteolytic changes specific to PsA with CBCT was exceeded 1.8–4.1 times in comparison with SR.
As a result of calculation and comparison of the direct costs for wrists and hands different ray researches (See the Table 2) it was found that its results were comparable for CP and CBCT.
In addition,
the implementation of CBCT is approximately 3.6 times cheaper than MSCT of this anatomical segment and MRI – in 7.2 times.