Parsik Radiology

Composition of long-view radiographs

Parsik Stitch places overlapping DX and CR exposures of the full spine, the full leg, or a long bone into one derived image. Alignment is calculated on the clinical reference plane.

Method

Composition

Two to six exposures from one acquisition are combined into a derived DICOM image. The image is stored with the source images and does not replace them. One exposure, the reference tile, is copied without change, including its display window. The remaining exposures are mapped onto that grey scale from the anatomy shared in the overlap. The order of grey values is preserved: air, then soft tissue, then bone. The mapping does not add, remove, or locally alter structure.

Review

Each result is marked PASS, REVIEW, or FAIL, and includes a confidence score and the reasons for that mark. The seam is indicated, and a QC image shows the overlap. REVIEW and FAIL are not transferred to PACS until a user confirms them. The decision is applied on the server.

Record

The same input and the same configuration produce the same composite. The measurement scale is written in the DICOM header, including the reference plane and the source of that scale. Angles do not depend on the plane height. Absolute lengths do.

Reference plane

When the tube and the detector move together, a point on the detector and a point in the patient are displaced by different amounts. The difference is parallax: delta = d × h / (SID − h). A ruler or collimator edge lies near the detector. Vertebral bodies and the long-bone axis lie on the clinical reference plane, above the detector. Parsik Stitch aligns on that plane and records the scale applied. The figure shows this geometry. It is not a measurement of product performance, and it is not a clinical image.

1800 mm
150 mm

Mechanical step, d: 200 mm in this figure

Displacement at the detector
200.0 mm
Displacement at the reference plane
218.2 mm
Parallax difference
18.2 mm

Deployment

  • The study is listed in the radiologist worklist in Parsik. A separate workstation and a separate login are not required.
  • A hardware encoder, the modality stitching option, and mechanical metadata from the X-ray system are not required.
  • The same Parsik Stitch workflow is used across X-ray systems from different manufacturers.

Users

Radiologist

The composite is displayed with the source images, the seam, the QC image, and the measurement scale. The status is PASS, REVIEW, or FAIL.

Radiographer

Acquisition remains on the existing modality. Review of the composite is done in Parsik.

Imaging IT

Access is through the browser. Exchange uses DICOM. Processing runs on the hospital gateway. A dedicated stitching workstation is not required.

Hospital management

One composition workflow applies to the X-ray systems in the department, without a separate stitching licence for each manufacturer.

Limits of use

  • Parsik Stitch does not produce a diagnosis and does not generate a report.
  • It is not used to plan an operation, to guide a procedure, or to select an implant size.
  • It does not sharpen or alter image content. Pixels outside the reference tile are mapped onto the reference grey scale only.
  • Patients under 18 years of age are outside the intended use of this version.
  • For absolute lengths that affect a clinical decision, a radiopaque marker of known size at the level of the anatomy, used with the viewer Calibration tool, remains the reference method. Angles do not depend on the height of the reference plane.

Further information

Does the composite replace the original exposures?

No. The derived image is stored with the source images. Measurements that depend on the acquired pixel values use the original exposures.

Is a vendor stitching option or an encoder required?

No. Parsik Stitch does not use mechanical metadata, a hardware encoder, or the stitching software of the modality.

Is every result transferred to PACS without review?

No. REVIEW and FAIL require confirmation by a user before transfer. The status and the confidence score are stored with the result.

Which examinations are included?

Adult full spine, full leg, and long bone, acquired as DX or CR in one session. Fluoroscopy, CT, and MR are outside this use. Patients under 18 years of age are outside this version.

Meeting regarding Parsik Stitch

Send the name of your institution and a short note on your long-view examinations. We will reply to arrange a meeting.