What are CT & MRI Procedures, Consults & Premiums

What are CT & MRI Procedures, Consults & Premiums

Summary / Description 
This article helps Ontario CT & MRI community clinics and billing teams build a clean “procedure catalogue” that maps clinic-facing MRI procedure names to the correct OHIP MRI service codes (base + repeats + contrast add-on). It also includes a concise reference to key Diagnostic Radiology (33) consultation/second-opinion codes and after-hours premiums that often come up in MRI/CT workflow.

Applies to

  • HYPEMedical (billing workflow)
  • HYPEMedical_WTIS
  • Ontario community MRI clinics, DI admins, billing agents

Keywords
OHIP MRI, X421, X425, X431, X435, X441, X445, X446, X447, X451, X455, X461, X465, X471, X475, X488, X489, X487,  MRI CT procedure mapping, Diagnostic Radiology 33, A330, A332, A335, A365, A331, A338, E406, E407, E408, professional component, technical component.

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1) Key concepts you must get right

A. Professional vs Technical billing (context for DI environments)

Diagnostic Radiology services are split into:

  • Professional (P) component → claimed as fee code + C suffix
  • Technical (H) component → claimed as fee code + B suffix

This matters when your environment mixes technical performance (clinic) with professional interpretation (radiologist group), or when you’re validating who is billing what.

B. “Study regions” matter (especially for second opinions)

The “CT/MRI study” regions are explicitly defined (e.g., head, neck, thorax, abdomen, pelvis, extremities, spine segments, breast for MRI).

2) WTIS: what “In-scope WTIS Procedures” means

In WTIS DI workflows, “in-scope procedures” generally means the standardized WTIS procedure categories that Ontario Health expects to be reported (i.e., your clinic selects which MRI procedure types you will submit/track). The WTIS specification includes MRI procedure category lists (e.g., MRI head, MRI spine, MRI extremity/joints, etc.) used for integration/mapping.

Practical takeaway:

  • Your clinic-facing procedure list (what staff pick) should map to:
    1. OHIP billing codes (for invoicing), and
    2. WTIS MRI procedure categories (for WTIS reporting / in-scope selection), where applicable.

3) How to build a clean “procedure catalogue” in HYPEMedical

Use this approach (works well for clinics and billing agents):

  1. Create clinic-friendly procedure names (what staff recognize)
    • Example: “MRI Knee (Right)”, “MRI Brain w/ Contrast”, “MRI Abdomen + Pelvis”
  2. Map each procedure to OHIP codes using:
    • Base code (the primary region code)
    • Repeat code (when additional planes/sequences apply, up to the regional maximum)
    • Contrast add-on (when gadolinium is used)
  3. Add Notes for staff/billers (rules like head-repeat max 2, extremity multi-joint rule, abdomen vs pelvis split).

 

4) MRI procedure mapping sheet (24 clinic-facing examples)

Important: This table is intended as a practical clinic catalogue template. Always confirm protocol-specific coding and any payer rule updates before standardizing. Repeat limits and key codes shown below follow the OHIP MRI code listing used here.

Legend

  • Contrast add-on: X487 (when gadolinium is used)
  • Head repeats: max 2 repeats (X425)
  • Most other regions: repeats often max 3 (see per-region repeat line)
  • Multi-extremity/joint studies: use X488 (base) + X489 (repeat)

Procedure name (clinic-facing)

Region

Base code

Repeat code

Contrast add-on

Notes

MRI Brain (routine)

Head

X421

X425

X487

Head repeats max 2

MRI Brain w/ Contrast

Head

X421

X425

X487

Add contrast when used

MRI Pituitary

Head

X421

X425

X487

Head region; protocol may drive repeats

MRI IAC

Head

X421

X425

X487

Head region

MRI Orbits

Head

X421

X425

X487

Head region

MRI Soft Tissue Neck

Neck

X431

X435

X487

Neck repeats max 3

MRI Neck w/ Contrast

Neck

X431

X435

X487

—

MRI Chest / Thorax

Thorax

X441

X445

X487

Thorax repeats max 3

MRI Cardiac (if billed as thorax MRI in your workflow)

Thorax

X441

X445

X487

Confirm protocol-specific billing rules

MRI Breast (Unilateral)

Breast

X446

X447

X487

Breast has its own base/repeat

MRI Breast (Bilateral)

Breast

X446

X447

X487

Document bilateral logic in Notes

MRI Abdomen (general)

Abdomen

X451

X455

X487

Abdomen repeats max 3

MRI Liver

Abdomen

X451

X455

X487

Abdomen category

MRI MRCP

Abdomen

X451

X455

X487

Abdomen category

MRI Pelvis (general)

Pelvis

X461

X465

X487

Pelvis repeats max 3

MRI Prostate

Pelvis

X461

X465

X487

Pelvis category

MRI Female Pelvis

Pelvis

X461

X465

X487

Pelvis category

MRI Knee (Right/Left)

Extremity/Joint

X471

X475

X487

Extremity repeats max 3

MRI Shoulder (Right/Left)

Extremity/Joint

X471

X475

X487

—

MRI Hip (Right/Left)

Extremity/Joint

X471

X475

X487

Hip often treated as extremity/joint in clinic catalogues

MRI Ankle (Right/Left)

Extremity/Joint

X471

X475

X487

—

MRI Wrist (Right/Left)

Extremity/Joint

X471

X475

X487

—

MRI Two Joints (e.g., both knees)

Multi-extremity/joints

X488

X489

X487

Use multi-joint rule codes

MRI Three+ Joints (e.g., both knees + ankle)

Multi-extremity/joints

X488

X489

X487

X489 repeats max 3

 

Notes you’ll likely want to standardize in your catalogue

  • Pelvis vs Abdomen split: keep separate procedure options when both are performed (“MRI Abdomen” vs “MRI Pelvis” vs “MRI Abdomen + Pelvis”) so billing/reporting stays consistent with study-region definitions used elsewhere (including second-opinion logic).
  • Contrast add-on: add X487 only when gadolinium is actually used.
  • Repeat limits: head max 2 repeats; many other regions allow up to 3 repeats (confirm in the code descriptions you rely on).

5) Diagnostic Radiology (33) quick reference for MRI/CT environments

A. Second opinion codes (CT/MRI)

  • A330 = second opinion of CT study (per study)
  • A332 = second opinion of MRI study (per study)
    Rules include: max one per study per patient per 30 days; and E406–E408 are not payable with A330/A332.

B. Consultations

  • A335 = Diagnostic radiology consultation (but not eligible for CT/MRI; use A330/A332 instead)
  • A365 = special interventional radiological consultation (≥50 minutes; strict conditions)

C. Minor assessments (procedure not performed)

  • A331 = minor assessment when planned procedure cancelled
  • A338 = minor assessment when procedure deemed inadvisable / not done

D. After-hours CT/MRI interpretation via PACS

  • E406 / E407 / E408 = urgent CT/MRI interpretation premiums (in addition to CT/MRI service) with specific conditions, and not payable with A330/A332.

6) FAQ

Q: If we do not perform MRI for a region, should it be “in-scope” for WTIS?

Generally, “in-scope” should match what your site actually performs and intends to report (use the WTIS procedure category list for MRI as your guide).

Q: What’s the safest way to avoid procedure-name confusion at the front desk?

Use clinic-friendly names (e.g., “MRI Knee (R)” / “MRI Knee (L)” / “MRI Both Knees”) and attach short Notes like “multi-joint rule” and “contrast add-on when used.”

Q: Why do we separate Abdomen vs Pelvis instead of one combined “Abdo/Pelvis”?

Because study regions are explicitly defined in radiology billing contexts, and consistent separation prevents downstream confusion in billing logic, reporting, and second-opinion rules.

 

CT Section — OHIP Procedure Mapping for Community Clinics (Clinic-Facing Examples)

How CT codes work in OHIP (at a glance)

For CT, the OHIP professional fee is typically selected based on:

  1. Anatomic region (head, neck, thorax, abdomen, pelvis, spine, extremities), and
  2. Contrast type:
  • Without IV contrast
  • With IV contrast
  • With and without IV contrast (combined phases)

OHIP uses different codes for each contrast type (i.e., contrast is usually not an “add-on” code for CT; you bill the correct CT code for the contrast performed).

CT procedure mapping sheet (24 clinic-facing examples)

Columns: Procedure name → Region → Base code → Repeat code → Contrast add-on → Notes
Convention used here:

  • Base code = “without IV contrast” code
  • Repeat code = “with IV contrast” code (use instead of base when contrast is used)
  • Contrast add-on = “with and without IV contrast” code (use instead of base when both phases are done)

Procedure name (clinic-facing)

Region

Base code

Repeat code

Contrast add-on

Notes

CT Head (no contrast)

Head

X400

X401

X188

Use X401 if IV contrast; use X188 if both phases.

CT Head (with IV contrast)

Head

X400

X401

X188

Bill X401 (not X400).

CT Head (with & without contrast)

Head

X400

X401

X188

Bill X188 (not X400/X401).

CT Neck (no contrast)

Neck

X403

X404

X124

Soft tissue neck variants.

CT Neck (with IV contrast)

Neck

X403

X404

X124

Bill X404 when contrast used.

CT Neck (with & without contrast)

Neck

X403

X404

X124

Bill X124 when both phases done.

CT Chest / Thorax (no contrast)

Thorax

X406

X407

X125

“Thorax” in OHIP CT set.

CT Chest / Thorax (with IV contrast)

Thorax

X406

X407

X125

Bill X407 when contrast used.

CT Chest / Thorax (with & without contrast)

Thorax

X406

X407

X125

Bill X125 for both phases.

CT Abdomen (no contrast)

Abdomen

X409

X410

X126

Abdomen CT variants.

CT Abdomen (with IV contrast)

Abdomen

X409

X410

X126

Bill X410 when contrast used.

CT Abdomen (with & without contrast)

Abdomen

X409

X410

X126

Bill X126 for both phases.

CT Pelvis (no contrast)

Pelvis

X231

X232

X233

Pelvis CT variants.

CT Pelvis (with IV contrast)

Pelvis

X231

X232

X233

Bill X232 when contrast used.

CT Pelvis (with & without contrast)

Pelvis

X231

X232

X233

Bill X233 for both phases.

CT Spine(s) (no contrast)

Spine(s)

X415

X416

X128

“Spine(s)” in OHIP CT set.

CT Spine(s) (with IV contrast)

Spine(s)

X415

X416

X128

Bill X416 when contrast used.

CT Spine(s) (with & without contrast)

Spine(s)

X415

X416

X128

Bill X128 for both phases.

CT Extremity (no contrast)

Extremities

X412

X413

X127

“One or more” extremities.

CT Extremity (with IV contrast)

Extremities

X412

X413

X127

Bill X413 when contrast used.

CT Extremity (with & without contrast)

Extremities

X412

X413

X127

Bill X127 for both phases.

CT Cardio-thoracic (e.g., cardiac/chest)

Cardio-thoracic

X235

—

—

Single listed code for this category.

CT Colonography

Colon

X234

—

—

Dedicated colonography code.

CT-guided biopsy (guidance)

Interventional (CT guidance)

X168

—

—

Guidance fee code (pairing rules depend on the underlying procedure).


Optional CT “add-on” style code (when applicable)

  • X417 — 3D CT acquisition sequencing + post-processing (minimum 60 slices; max 1 scan per patient per day) — use only when that 3D acquisition/post-processing criterion is met.

Related radiology premium reminder (often missed)

  • After-hours premiums E406/E407/E408 are limited to max one per patient, per physician, per day, regardless of the number of CT and/or MRI images interpreted.

(a) Quick Answer

CT billing in Ontario is primarily selected by two things:

  1. Region (Head / Neck / Thorax / Abdomen / Pelvis / Spine / Extremities), and
  2. Contrast performed (No IV contrast vs With IV contrast vs With & without IV contrast).

Rule of thumb: CT contrast is usually not an add-on—you bill the specific CT code that matches the contrast type for that region. Use dedicated codes for special studies like CT colonography (X234), CT cardio-thoracic (X235), and CT-guided biopsy guidance (X168). Region codes used in the mapping below come from the OHIP CT code list. ()

(b) Decision Tree (Region → Contrast → Code)

Use this decision tree when a staff member has a clinic-facing procedure name and needs the OHIP CT code.

Step 1 — Pick the Region

Choose the CT study region:

  • Head
  • Neck
  • Thorax (Chest)
  • Abdomen
  • Pelvis
  • Spine(s)
  • Extremity(ies)

Or special CT studies:

  • CT Colonography
  • CT Cardio-thoracic
  • CT-guided biopsy (guidance)

Step 2 — Pick Contrast Type

For standard regions, select one:

  • No IV contrast
  • With IV contrast
  • With & without IV contrast (both phases)

Step 3 — Use the correct code

HEAD

  • No IV contrast → X400
  • With IV contrast → X401
  • With & without IV contrast → X188 ()

NECK

  • No IV contrast → X403
  • With IV contrast → X404
  • With & without IV contrast → X124 ()

THORAX (CHEST)

  • No IV contrast → X406
  • With IV contrast → X407
  • With & without IV contrast → X125 ()

ABDOMEN

  • No IV contrast → X409
  • With IV contrast → X410
  • With & without IV contrast → X126 ()

PELVIS

  • No IV contrast → X231
  • With IV contrast → X232
  • With & without IV contrast → X233 ()

SPINE(S)

  • No IV contrast → X415
  • With IV contrast → X416
  • With & without IV contrast → X128 ()

EXTREMITY(IES)

  • No IV contrast → X412
  • With IV contrast → X413
  • With & without IV contrast → X127 ()

Special CT Studies (no contrast decision needed)

  • CT Colonography → X234 ()
  • CT Cardio-thoracic → X235 ()
  • CT-guided biopsy (guidance) → X168 ()

Optional “Only if performed” add-on

  • 3D CT acquisition sequencing + post-processing → X417 (use only when the 3D criteria are met; max 1/day). ()