NPI registry status
Active
2026 NPPES data Diagnostic Radiology Physician NPI 1558351494 M.D.
Verify on CMS → Guillermo Walters, M.D.
Diagnostic Radiology Physician in Leominster, Massachusetts.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 39,551 in Diagnostic Radiology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
11
Medicare Part D claims · Diagnostic Radiology Physician avg: 63
MIPS score
97/100
▲ 14 pts above national avg 83.5 · Exceptional
What the federal data shows
Guillermo Walters, M.D. reported a CMS MIPS final score of 97/100 - above the 83.5 national average - and filed 11 Medicare Part D claims in 2023.
- 97/100
- MIPS score · +14 vs avg
- 11
- Part D claims, 2023
- Likely
- board-certified (heuristic)
- ≥84th
- pct among measured MIPS (lower-bound band)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Guillermo Walters, M.D.'s MIPS score vs every measured U.S. clinician
CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure. Clinicians whose score CMS assigned without scoring any category are excluded.
97 ≥ 84th percentile 84% of 454,083 measured providers are in lower value bands
Each bar is a band; taller bars hold more measured providers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
The percentile is a conservative whole-score-point band: it counts only measured clinicians in lower score bands. A CMS MIPS metric is not a recommendation or a clinical-quality rating by PlainDoctor. See methodology § corpus placement.
Source CMS Merit-based Incentive Payment System (MIPS) · 2023
Where Guillermo Walters, M.D. sits
This provider among diagnostic radiology physician peers
Across the 945 diagnostic radiology physician providers who report both Medicare Part D prescribing and a MIPS quality score, Guillermo Walters, M.D. writes more Part D claims than 0% of them and scores higher on MIPS quality than 86% - placing this provider in the lower-volume, high-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.
Part D claim volume vs MIPS quality, by specialty percentile
Each dot is one diagnostic radiology physician peer from a representative sample of 60; the gold marker is Guillermo Walters, M.D.. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.
✓
Board certification likely (heuristic, not verified)
Guillermo Walters, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Guillermo Walters, M.D.?
High performer (top quartile)Primary specialty
Diagnostic Radiology Physician
Medicare Part D claims
11 83% vs specialty avg
MIPS final score
97/100 13.5 pts vs avg
Specialty distribution in Massachusetts
How Diagnostic Radiology Physician compares to other specialties among Massachusetts providers
Medicare quality performance, MIPS
Guillermo Walters, M.D.'s 2023 MIPS final score plotted against the Diagnostic Radiology Physician national average
- MIPS Final Score
- 97/100
- vs 83.5 national avg · 2023 performance year
MIPS final score (Diagnostic Radiology Physician) - 97/100 vs national avg 83.5
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Guillermo Walters, M.D. appears in the CMS NPPES registry as a Diagnostic Radiology Physician provider holding M.D. credentials at 60 HOSPITAL RD, Leominster, MA, 01453, with a listed phone of (978) 466-2714. NPI 1558351494 was issued on 10/23/2005.
Medicare Part D records for calendar year 2023 show 11 prescription claims written by this provider, covering N/A Medicare beneficiaries and totaling roughly $369 in drug spend. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 97/100 for the 2023 performance year (Quality 78.1), compared with the 83.5 average among clinicians with a measured score.
Diagnostic Radiology Physician is a mid-sized specialty nationwide, with 39,551 enrolled providers across 56 states and an average of 63 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.
Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.
Practice Address
Provider Details
| NPI | 1558351494 |
|---|---|
| Specialty | Diagnostic Radiology Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 10/23/2005 |
CMS Quality Score (MIPS)
Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.
97.0218
Final Score
Measured-score avg: 83.5
78.0983
Quality
100
Promoting Interoperability
Reporting: Alternative Payment Model
Hospital and facility affiliations
Facilities where Guillermo Walters, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Umass Memorial Medical Group Inc
Worcester, MA
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
License & disciplinary context - Massachusetts BORIM 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~38K Massachusetts medical licensees in 2023 - they are NOT specific to Guillermo Walters, M.D.. To verify Guillermo Walters, M.D.'s current license status, search the BORIM public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
80
Total board actions, Massachusetts 2023
Across 78 cases
2.11
Actions per 1,000 licensees
Massachusetts statewide rate
probation
Most common action type
29 cases
BORIM publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Massachusetts disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
11
Total Claims
$369
Total Drug Cost
N/A
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 33
- Total Day Supply
- 990
Patient Demographics
- Average Patient Age
- 89.0 years
- Avg HCC Risk Score
- 1.19
Diagnostic Radiology Physician Overview
How Guillermo Walters, M.D. fits within the Diagnostic Radiology Physician landscape nationally.
39,551
Diagnostic Radiology Physician Providers in US
56
States with Diagnostic Radiology Physician
63
Avg Claims per Provider
Guillermo Walters, M.D.'s 11 claims are below the specialty average of 63.
Nearby Diagnostic Radiology Physician Providers in Massachusetts
Other clinicians with the same primary specialty enrolled in Massachusetts, drawn from the same CMS NPPES roster as Walters.
Aly Abayazeed
Worcester, MA
Dr. Mashya Abbassi
MD
Boston, MA
Dr. Gerald Abbott
MD
Boston, MA
Dr. Shadi Abdar Esfahani
MD, MPH
Boston, MA
Dr. Essmaeel Abdel-Dayem
MD
South Weymouth, MA
Compare Diagnostic Radiology Physician nationally: see state-by-state distribution →
Before you book an appointment
Use this federal record as your verification checklist, not as a recommendation.
- Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
- Check the active license and any disciplinary history with the Massachusetts medical board, federal registration is not a license check. Credential verification guide
- Weigh a second option: compare this provider with a nearby Diagnostic Radiology Physician peer on Medicare volume and prescribing patterns. Compare providers
Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.
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Frequently Asked Questions
What is Guillermo Walters, M.D.'s specialty? ▼
Guillermo Walters, M.D. specializes in Diagnostic Radiology Physician and practices in Leominster, Massachusetts. Credentials: M.D..
How much does Guillermo Walters, M.D. prescribe under Medicare Part D? ▼
In 2023, Guillermo Walters, M.D. wrote 11 Medicare Part D claims totaling $369 in drug costs for N/A beneficiaries.
What is Guillermo Walters, M.D.'s Medicare quality score? ▼
Guillermo Walters, M.D. has a CMS MIPS Final Score of 97/100 (Quality: 78.1). The average MIPS Final Score across the 454,083 clinicians with at least one published category score is 83.5; clinicians whose score CMS assigned without scoring any category are excluded from that average. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is Guillermo Walters, M.D. located? ▼
Guillermo Walters, M.D. is located at 60 HOSPITAL RD, Leominster, MA, 01453. Phone: (978) 466-2714.
What is Guillermo Walters, M.D.'s NPI number? ▼
Guillermo Walters, M.D.'s National Provider Identifier (NPI) is 1558351494, issued on 10/23/2005.
How many Diagnostic Radiology Physician providers are there in the US? ▼
There are 39,551 Diagnostic Radiology Physician providers across 56 states in the US. The average Diagnostic Radiology Physician provider writes 63 Medicare Part D claims per year.
Does Guillermo Walters, M.D. accept Medicare? ▼
Guillermo Walters, M.D. appears in CMS Medicare data with 11 Part D claims and N/A Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Guillermo Walters, M.D.'s credentials? ▼
Guillermo Walters, M.D.'s NPI is 1558351494 with credentials M.D.. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Quality Performance
- CMS Merit-based Incentive Payment System (MIPS) - 2023 performance year.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.