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CPT code 78645: CSF shunt study, shunt patency assessment2026 Medicare rate & RVUs in Connecticut

Nuclear medicine imaging tracks radiotracer movement through a cerebrospinal fluid shunt to investigate suspected impaired flow or shunt malfunction.

CMS RVU26DEffective Oct 1, 2026One payment locality686 Medicare services in 2024

In Connecticut, Medicare pays $306.50 for 78645 in the office.

$306.50Office (non-facility)
Not available in this settingHospital or facility
+7.5%vs the national office rate ($285.24)

Check a contract rate as a % of Medicare · 78645 nationwide

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

We’ll open 78645 for the payment locality that covers the ZIP.

On this page 11 sections
  1. Rate in Connecticut
  2. What 78645 covers
  3. Compared with other areas
  4. Rate map
  5. How it’s calculated
  6. Payment rules
  7. Related codes
  8. Rate history
  9. Where it applies
  10. Billing questions
  11. Sources

What 78645 covers

This study evaluates flow through an implanted cerebrospinal fluid shunt, commonly when symptoms or other findings raise concern for obstruction or malfunction. A nuclear medicine team administers radiotracer through the shunt access point and obtains images to follow its movement through the shunt pathway. The study may help assess whether flow is occurring and where it appears impaired.

Report 78645 for the shunt-focused radionuclide evaluation, rather than a study directed at general CSF circulation, ventricular imaging, or leak localization. Documentation should identify the clinical concern, the shunt evaluated, the radiotracer administration and imaging performed, and the interpretation of tracer progression. CMS recognizes professional and technical components: report modifier 26 for the interpretation, modifier TC for equipment and staff, or no component modifier for the global service. The professional and technical components are separately priced.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

How Connecticut compares for 78645

Across 109 of 109 payment localities, the office rate for 78645 runs from $246.74 in Arkansas to $402.69 in San Benito County, CA. Connecticut pays $306.50. The RVUs are the same everywhere; the geographic indexes change the dollars.

78645 in Connecticut vs other payment areas
  1. Connecticut · this page$306.50
  2. Los Angeles, CA · California$333.40+$26.90
  3. Washington, DC area · District of Columbia$333.52+$27.02
  4. Miami, FL · Florida$300.15−$6.35
  5. Chicago, IL · Illinois$290.15−$16.35
  6. Manhattan, NY · New York$330.75+$24.25
  7. Alaska · Alaska$310.55+$4.05

Other areas in Connecticut first, then benchmark localities. Bars start at $0.

Every other payment area

78645 in every other Medicare payment locality
Payment localityOfficeFacility
AlabamaAlabama$251.10—
ArkansasArkansas$246.74—
ArizonaArizona$276.68—
Bakersfield, CACalifornia$309.89—
Chico, CACalifornia$309.65—
El Centro, CACalifornia$309.67—
Fresno, CACalifornia$309.65—
Hanford, CACalifornia$309.65—

78645 rates by state

Office rate range in each state. Select a state to see its payment localities.

MEWIVTNHMTNDMNMINYMARIWAIDWYSDIAILINOHPANJCTORNVUTCONEMOKYWVVAMDDECAAZNMKSOKARTNNCSCDCTXLAMSALGAFLAKHI

Explore a state

Local rates. Clear comparisons.

Hover or focus a tile to see its rate range. Select it to open the state’s fee schedule.

$246.74

$356.17

Color shows the midpoint of each state’s locality range.

View every state and territory as a table
78645 office rate range by state
State / territoryOffice rate rangeLocalities
AK$310.551
AL$251.101
AR$246.741
AZ$276.681
CA$309.65–$402.6929
CO$301.771
CT$306.501
DC$333.521
DE$281.901
FL$274.98–$300.153
GA$257.26–$290.062
GU$320.271
HI$320.271
IA$261.201
ID$262.731
IL$263.79–$294.564
IN$264.611
KS$258.591
KY$255.731
LA$254.79–$270.042
MA$298.99–$336.912
MD$288.38–$333.523
ME$263.12–$281.882
MI$262.63–$277.842
MN$291.011
MO$248.76–$272.583
MS$247.871
MT$285.241
NC$266.601
ND$283.661
NE$263.261
NH$295.731
NJ$310.53–$328.822
NM$263.881
NV$285.061
NY$271.26–$338.605
OH$262.311
OK$256.411
OR$283.39–$314.152
PA$263.46–$296.912
PR$288.111
RI$294.021
SC$264.791
SD$283.471
TN$259.991
TX$261.31–$300.288
UT$269.141
VA$279.97–$333.522
VI$288.111
VT$281.291
WA$298.83–$345.592
WI$272.311
WV$251.831
WY$284.551

See 78645 in every payment locality

How the 78645 rate is calculated

Each of 78645’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

How the rate is built · 78645

RVUs × geographic indexes × conversion factor

Office or facility?

Work0.56

0.56 RVUs× 1.000 GPCI

Practice expense7.90

7.90 RVUs× 1.000 GPCI

Malpractice0.08

0.08 RVUs× 1.000 GPCI

Adjusted RVUs

8.5400

Conversion factor

$33.4009

Medicare rate

$285.24

Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.

The exact Connecticut inputs and CMS source lines

PPRRVU2026_Oct_nonQPP.csv

9,470

Code
78645
Physician work
0.56
Practice expense
7.90
Malpractice
0.08

GPCI2026.csv

38

Locality
Connecticut
Physician work
1.020
Practice expense
1.077
Malpractice
1.210
Office calculation for 78645 in Connecticut
ComponentRVULocality factorAdjusted
Physician work0.56× 1.0200.5712
Practice expense7.90× 1.0778.5083
Malpractice0.08× 1.2100.0968
Total RVUs9.1763
Conversion factor× 33.4009

Office rate, Connecticut$306.50

Office: (0.56 × 1.02 + 7.9 × 1.077 + 0.08 × 1.21) × $33.4009 = $306.50

Open 78645 in the RVU calculator

Payment rules and modifiers for 78645

The CMS indicators that decide how 78645 is paid alongside other services.

CMS payment indicators · 78645

CSF shunt study, shunt patency assessment

RuleCMS valueWhat it means
Global periodXXXThe global surgery concept doesn’t apply.
Multiple procedures0No multiple-procedure reduction.
Bilateral (modifier 50)0The 150% bilateral adjustment doesn’t apply.
Assistant at surgery (80/81/82/AS)0Not paid without supporting documentation.
Co-surgeons (62)0Not permitted.
Team surgery (66)0Not permitted.
Professional/technical1Diagnostic test with separate professional (26) and technical (TC) components.

What modifiers do to the payment

Modifier 26 · payment effect

With and without the modifier

78645 without 26 · national office

$285.24

CSF shunt study, shunt patency assessment

78645-26 · Professional component

$25.72

Pays only the interpretation and report.

When to use modifier 26

Codes related to 78645

Related codes aren’t interchangeable: bill the code that matches the service performed.

Codes related to 78645
CodeHow it relatesOffice range, Connecticut
Used instead
78630CSF scan, cisternographyCSF cisternography evaluates CSF circulation rather than flow through an implanted shunt.$316.47
78635CSF imaging, ventricular flow studyCSF ventriculography evaluates ventricular CSF pathways, not shunt patency.$316.51
78650CSF leak imaging, leak detection and localizationCSF leak imaging addresses suspected leakage rather than shunt flow.$263.23

How 78645 has changed in Connecticut

78645 · Office / nonfacility

$306.50

Effective 2026-10-01

The base rate is $0.45 higher than on 2025-10-01, moving from $306.05 to $306.50 (0.1%).

It is unchanged from the immediately preceding available release, effective 2026-07-01.

Base rate by release · bars start at $0 · select a bar to compare

One bar per available release, ordered by effective date. Missing rates remain gaps. These comparisons hold the code, setting and locality identifiers constant; they do not isolate which policy or input caused a change.

What changed, release by release

  1. January 1, 2026

    RVU26A

    $306.05changed to$306.50

    • Conversion factor 32.3465 changed to 33.4009
    • Work RVU 0.57 changed to 0.56
    • Practice expense RVU 8.05 changed to 7.90
    • Work GPCI 1.022 changed to 1.020
    • Practice expense GPCI 1.091 changed to 1.077
    • Malpractice GPCI 1.207 changed to 1.210

    Held through RVU26B, RVU26C, RVU26D.

  2. January 1, 2025

    RVU25A

    $320.80changed to$306.05

    • Conversion factor 33.2875 changed to 32.3465
    • Practice expense RVU 8.20 changed to 8.05
    • Malpractice RVU 0.09 changed to 0.08

    Held through RVU25B, RVU25C, RVU25D.

  3. March 9, 2024

    RVU24AR

    $315.57changed to$320.80

    • Conversion factor 32.7442 changed to 33.2875

    Held through RVU24B, RVU24C, RVU24D.

  4. January 1, 2024

    RVU24A

    $334.26changed to$315.57

    • Conversion factor 33.8872 changed to 32.7442
    • Practice expense RVU 8.36 changed to 8.20
    • Malpractice RVU 0.06 changed to 0.09
    • Work GPCI 1.030 changed to 1.022
    • Practice expense GPCI 1.102 changed to 1.091
    • Malpractice GPCI 1.070 changed to 1.207

  5. January 1, 2023

    RVU23A

    $350.40changed to$334.26

    • Conversion factor 34.6062 changed to 33.8872
    • Practice expense RVU 8.50 changed to 8.36
    • Malpractice RVU 0.07 changed to 0.06
    • Work GPCI 1.037 changed to 1.030
    • Practice expense GPCI 1.114 changed to 1.102
    • Malpractice GPCI 0.934 changed to 1.070

    Held through RVU23B, RVU23C, RVU23D.

  6. January 1, 2022

    RVU22A

    $368.08changed to$350.40

    • Conversion factor 34.8931 changed to 34.6062
    • Practice expense RVU 8.88 changed to 8.50

    Held through RVU22B, RVU22C, RVU22D.

  7. January 1, 2021

    RVU21A

    $370.98changed to$368.08

    • Conversion factor 36.0896 changed to 34.8931
    • Practice expense RVU 8.64 changed to 8.88
    • Work GPCI 1.029 changed to 1.037
    • Practice expense GPCI 1.113 changed to 1.114
    • Malpractice GPCI 1.094 changed to 0.934

    Held through RVU21B, RVU21C, RVU21D.

  8. January 1, 2020

    RVU20A

    $374.00changed to$370.98

    • Conversion factor 36.0391 changed to 36.0896
    • Practice expense RVU 8.73 changed to 8.64
    • Work GPCI 1.021 changed to 1.029
    • Practice expense GPCI 1.112 changed to 1.113
    • Malpractice GPCI 1.255 changed to 1.094

    Held through RVU20B, RVU20C, RVU20D.

  9. January 1, 2019

    RVU19A

    $380.39changed to$374.00

    • Conversion factor 35.9996 changed to 36.0391
    • Practice expense RVU 8.90 changed to 8.73

    Held through RVU19B, RVU19C, RVU19D.

  10. January 1, 2018

    RVU18AR1

    $378.83changed to$380.39

    • Conversion factor 35.8887 changed to 35.9996
    • Practice expense RVU 8.85 changed to 8.90
    • Work GPCI 1.023 changed to 1.021
    • Practice expense GPCI 1.117 changed to 1.112
    • Malpractice GPCI 1.244 changed to 1.255

    Held through RVU18B, RVU18C, RVU18D.

  11. January 1, 2017

    RVU17A

    $375.98changed to$378.83

    • Conversion factor 35.8043 changed to 35.8887
    • Practice expense RVU 8.77 changed to 8.85
    • Work GPCI 1.024 changed to 1.023
    • Practice expense GPCI 1.121 changed to 1.117
    • Malpractice GPCI 1.232 changed to 1.244

    Held through RVU17B, RVU17C, RVU17D.

  12. January 1, 2016

    RVU16A

    $376.94changed to$375.98

    • Conversion factor 35.9335 changed to 35.8043
    • Practice expense RVU 8.76 changed to 8.77

    Held through RVU16B, RVU16C, RVU16D.

  13. July 1, 2015

    RVU15C

    $375.06changed to$376.94

    • Conversion factor 35.7547 changed to 35.9335

    Held through RVU15D.

  14. January 1, 2015

    RVU15A

    $366.57changed to$375.06

    • Conversion factor 35.8228 changed to 35.7547
    • Practice expense RVU 8.58 changed to 8.76
    • Malpractice RVU 0.06 changed to 0.07
    • Practice expense GPCI 1.116 changed to 1.121
    • Malpractice GPCI 1.234 changed to 1.232

    Held through RVU15B.

  15. January 1, 2014

    RVU14A

    No ratechanged to$366.57

    Held through RVU14B, RVU14C, RVU14D.

  16. January 1, 2013

    RVU13AR

    Earliest loaded release: No rate

    Held through RVU13B, RVU13C, RVU13D.

Rates in every CMS release
Effective fromOfficeFacilityCMS release
2026-10-01$306.50Not available in this settingRVU26D
2026-07-01$306.50Not available in this settingRVU26C
2026-04-01$306.50Not available in this settingRVU26B
2026-01-01$306.50Not available in this settingRVU26A
2025-10-01$306.05Not available in this settingRVU25D
2025-07-01$306.05Not available in this settingRVU25C
2025-04-01$306.05Not available in this settingRVU25B
2025-01-01$306.05Not available in this settingRVU25A
2024-10-01$320.80Not available in this settingRVU24D
2024-07-01$320.80Not available in this settingRVU24C
2024-04-01$320.80Not available in this settingRVU24B
2024-03-09$320.80Not available in this settingRVU24AR
2024-01-01$315.57Not available in this settingRVU24A
2023-10-01$334.26Not available in this settingRVU23D
2023-07-01$334.26Not available in this settingRVU23C
2023-04-01$334.26Not available in this settingRVU23B
2023-01-01$334.26Not available in this settingRVU23A
2022-10-01$350.40Not available in this settingRVU22D
2022-07-01$350.40Not available in this settingRVU22C
2022-04-01$350.40Not available in this settingRVU22B
2022-01-01$350.40Not available in this settingRVU22A
2021-10-01$368.08Not available in this settingRVU21D
2021-07-01$368.08Not available in this settingRVU21C
2021-04-01$368.08Not available in this settingRVU21B
2021-01-01$368.08Not available in this settingRVU21A
2020-10-01$370.98Not available in this settingRVU20D
2020-07-01$370.98Not available in this settingRVU20C
2020-04-01$370.98Not available in this settingRVU20B
2020-01-01$370.98Not available in this settingRVU20A
2019-10-01$374.00Not available in this settingRVU19D
2019-07-01$374.00Not available in this settingRVU19C
2019-04-01$374.00Not available in this settingRVU19B
2019-01-01$374.00Not available in this settingRVU19A
2018-10-01$380.39Not available in this settingRVU18D
2018-07-01$380.39Not available in this settingRVU18C
2018-04-01$380.39Not available in this settingRVU18B
2018-01-01$380.39Not available in this settingRVU18AR1
2017-10-01$378.83Not available in this settingRVU17D
2017-07-01$378.83Not available in this settingRVU17C
2017-04-01$378.83Not available in this settingRVU17B
2017-01-01$378.83Not available in this settingRVU17A
2016-10-01$375.98Not available in this settingRVU16D
2016-07-01$375.98Not available in this settingRVU16C
2016-04-01$375.98Not available in this settingRVU16B
2016-01-01$375.98Not available in this settingRVU16A
2015-10-01$376.94Not available in this settingRVU15D
2015-07-01$376.94Not available in this settingRVU15C
2015-04-01$375.06Not available in this settingRVU15B
2015-01-01$375.06Not available in this settingRVU15A
2014-10-01$366.57Not available in this settingRVU14D
2014-07-01$366.57Not available in this settingRVU14C
2014-04-01$366.57Not available in this settingRVU14B
2014-01-01$366.57Not available in this settingRVU14A
2013-10-01Additional calculation requiredNot available in this settingRVU13D
2013-07-01Additional calculation requiredNot available in this settingRVU13C
2013-04-01Additional calculation requiredNot available in this settingRVU13B
2013-01-01Additional calculation requiredNot available in this settingRVU13AR

Price 78645 for an earlier date of service

Where the Connecticut rate applies

Connecticut is a Medicare payment area, not a city. Our Census mapping connects it to 215 cities and communities in Connecticut. Some span more than one payment area; confirm with the service ZIP.

  • Ansonia
  • Ball Pond
  • Baltic
  • Bantam
  • Bethel
  • Bethlehem Village
  • Bigelow Corners
  • Blue Hills

Browse all communities in Connecticut

78645 billing questions

When should I report 78645 instead of a CSF cisternography code?

Report 78645 when the imaging evaluates flow through an implanted CSF shunt. Cisternography evaluates CSF circulation rather than shunt patency.

How do I report the professional and technical portions?

Use modifier 26 for the professional interpretation and modifier TC for the technical service. Without either modifier, the claim represents the global service.

What documentation supports 78645?

Document the suspected shunt problem, the shunt evaluated, radiotracer administration, the imaging performed, and the interpreting clinician’s findings about tracer progression.

Is this the right code for locating a CSF leak?

No. 78645 evaluates an implanted shunt; code 78650 is associated with CSF leak imaging.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Show the CMS file lines behind this rate
RVUs for 78645PPRRVU2026_Oct_nonQPP.csv, line 9,470 (RVU26D)
Geographic factors for ConnecticutGPCI2026.csv, line 38 (RVU26D)

Open CMS sourceHow we calculate rates

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