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Diagnostic Radiology

Johannes H. Decker, MD

Works at hospitals in San Jose, CA · Stanford, CA · Pleasanton, CA · California

Summary

Dr. Johannes H. Decker, MD is a radiologist at 300 Pasteur Dr, Stanford, CA 94305. Phone: (650) 723-4000. Accepts Medicare assignment. In 2024, Johannes H. Decker had 993 Original Medicare patients and 1,600 services. NPI 1558892075. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

From official Medicare data

This page shows what Medicare's official clinician data says about Johannes H. Decker, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Johannes H. Decker accept Medicare assignment?
Yes. Medicare's clinician data says Johannes H. Decker accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Johannes H. Decker see?
In 2024, CMS data shows 993 Original Medicare patients and 1,600 services for Johannes H. Decker. This counts Original Medicare only and measures volume, not quality.
What is Johannes H. Decker's NPI number?
1558892075. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Johannes H. Decker, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients993
Services billed to Medicare1,600
Different services or procedures39
Participating Medicare providerYes
Average age of these patients76

Most frequent services

  1. Ct scan head or brain without contrast (70450)401 services
  2. Mri scan of brain before and after contrast (70553)204 services
  3. Ct scan of upper spine without contrast (72125)130 services
  4. Ct scan of blood vessels of neck with contrast (70498)85 services
  5. Mri scan of brain without contrast (70551)79 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

  • High blood pressure75%
  • High cholesterol75%
  • Arthritis49%
  • Diabetes34%
  • Chronic kidney disease34%
  • Ischemic heart disease32%

Hospitals where Johannes H. Decker works

Medicare's Facility Affiliation Data lists Johannes H. Decker at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

Practice locations

Addresses where Johannes H. Decker is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Johannes H. Decker as a member of this group (CMS data updated October 2, 2026).

  • Stanford Health Care3,122 clinicians in the group

Specialties

Find other Diagnostic Radiology doctors in California →

Other radiologists in Stanford

Clinicians with the same Medicare primary specialty in Stanford, CA — not a recommendation.

All radiologists in Stanford →

Other clinicians in Stanford Health Care

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Graduation year2017 (9 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1558892075
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians