RALPH MAXIMILLIAN KOENKER M.D.
NPI 1891734265
Radiology - Diagnostic Radiology in Greenbrae, CA

Q: What is Ralph Koenker's NPI number?

The NPI number for Ralph Koenker is 1891734265. It was assigned to this individual provider in the NPPES registry on June 4, 2006.

Q: Where is Ralph Koenker located?

Ralph Koenker practices at 250 Bon Air Rd, Greenbrae, CA 94904. The listed phone number is (415) 925-7000.

Q: What is Ralph Koenker's specialty?

The primary specialty registered for this NPI is Radiology, specializing in Diagnostic Radiology, with taxonomy code 2085R0202X.

Q: Is Ralph Koenker enrolled in Medicare?

Yes. Ralph Koenker is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Q: Which organizations bill Medicare for Ralph Koenker's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Ralph Koenker reassigns Medicare benefits to 4 organizations: Prima Medical Foundation (Novato, CA), California Advanced Imaging Medical Associates Inc (San Francisco, CA), Regents Univ Of California Ucsf (San Francisco, CA) and Sutter Valley Medical Foundation (Fairfield, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Ralph Koenker's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Q: When was this NPI record last updated?

The NPPES record for Ralph Koenker was last updated on June 28, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.

Active since June 04, 2006PECOS EnrolledAccepts Medicare Assignment

94.77/100

CMS Quality Rating

250 BON AIR RD, GREENBRAE, CA 94904(415) 925-7000 Get Directions Write a Review

NPPES record last updated: June 28, 2026. Verified against the NPPES registry weekly; last sync: October 25, 2026.

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About Ralph Maximillian Koenker M.d. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

RALPH MAXIMILLIAN KOENKER M.D. (NPI 1891734265) is an individual diagnostic radiology provider in Greenbrae, California, licensed in California (G60981) and active in the NPI registry since June 2006. He is enrolled in Medicare PECOS, maintains a secondary practice location in Novato, and is a graduate of University Of California, San Diego School Of Medicine (1985).

NPPES Registry Identity

NPI1891734265

Entity TypeIndividualMale

Primary Taxonomy2085R0202X

Provider Legal NameRALPH MAXIMILLIAN KOENKERCredential: M.D.

Location Address250 BON AIR RDGreenbrae, CA 94904-1702

Mailing AddressPo Box 6102Novato, CA 94948-6102 · (415) 884-3418 · Fax (415) 883-8082

Phone(415) 925-7000

Sole ProprietorNo

Medical School CMSUniversity Of California, San Diego School Of MedicineGraduated 1985

Enumeration DateJune 4, 2006

Last NPPES UpdateJune 28, 2026

NPPES CertifiedJune 28, 2026

✔ NPI 1891734265 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyRadiology · Diagnostic RadiologyAllopathic & Osteopathic Physicians

Taxonomy Code2085R0202X

License✔ Licensed in CA · G60981

Definition

A radiologist who utilizes x-ray, radionuclides, ultrasound and electromagnetic radiation to diagnose and treat disease.

Also ListedRadiology · NeuroradiologyTaxonomy 2085N0700X · License G60981 (CA)

Also ListedRadiology · Vascular & Interventional RadiologyTaxonomy 2085R0204X · License G60981 (CA)

250 BON AIR RD, Greenbrae, CA 94904

Open in Google Maps ↗

Secondary Practice Location 1

Location 1180 Rowland WayNovato, CA 94945-5009 · Phone (415) 290-1500

Other Identifiers 4

Medicaid00G609810CA

Other300121787CA · Railroad Medicare

Other00G609810CA · Blue Shield

Other300035771CA · Railroad Medicare

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Ralph Maximillian Koenker M.d. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID4789582909

PECOS Enrollment IDI20060209000255

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

Medicare enrollment records show Ralph Koenker reassigns Medicare billing to 4 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Prima Medical Foundation

7.7 mi

Clinic/Center

4 HAMILTON LANDING, SUITE 100
Novato, CA 94949

Reassigned Medicare billing, California enrollment
111 clinicians in this Medicare group

NPI 1811217946 (415) 884-1840

California Advanced Imaging Medical Associates Inc

13 mi

Diagnostic Radiology

1101 VAN NESS AVE
San Francisco, CA 94109

Reassigned Medicare billing, California enrollment
96 clinicians in this Medicare group

NPI 1881646909 (415) 600-6000

Regents Univ Of California Ucsf

13 mi

Internal Medicine

505 PARNASSUS AVE
San Francisco, CA 94143

Reassigned Medicare billing, California enrollment
339 clinicians in this Medicare group

NPI 1124439807 (415) 476-1000

Sutter Valley Medical Foundation

32 mi

Multi-Specialty

2720 LOW CT
Fairfield, CA 94534

Reassigned Medicare billing, California enrollment
3,056 clinicians in this Medicare group

NPI 1184859894 (707) 428-2731

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Areas of Expertise CMS Part B claims 101

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

X-ray of chest, 1 view 71045

A chest X-ray, 1 view, is a quick, painless test that produces images of the structures within your chest, such as your heart, lungs, and blood vessels. It helps in diagnosing conditions like pneumonia, heart problems, or lung cancer. You'll stand in front of a machine that emits X-rays, which pass through your body to create the image.

1,092 services912 patients

Ct scan head or brain without contrast 70450

A CT scan of the head or brain without contrast is a non-invasive imaging procedure. It uses X-rays to create detailed pictures of your brain, skull, and other structures inside your head. It helps to detect conditions like strokes, tumors, or injuries. No dye (contrast) is used in this test.

480 services453 patients

Ct scan of abdomen and pelvis with contrast 74177

A CT scan of the abdomen and pelvis with contrast is an imaging procedure. A special dye, called contrast, is used to make certain areas more visible. This can help identify issues such as infections, tumors, or other abnormalities. The procedure is painless and usually takes about 30 minutes.

268 services263 patients

Screening 3d breast mammography 77063

Screening 3D breast mammography is a procedure that uses low-dose X-rays to create detailed images of the breast. This allows for early detection of any unusual changes or growths. It's a non-invasive, outpatient procedure that typically takes about 30 minutes.

243 services243 patients

Screening mammography 77067

Screening mammography is a preventative measure that uses low-dose X-rays to take images of the chest area. It's a key tool in early detection of abnormalities, helping to identify issues before they become symptomatic. It is recommended annually for certain age groups.

243 services243 patients

X-ray of chest, 2 views 71046

A chest X-ray, 2 views, is a quick, painless test that creates pictures of the structures inside your chest, such as your heart, lungs, and blood vessels. Two different angles are used to get a comprehensive view. This helps in diagnosing conditions like pneumonia, heart problems, or lung cancer.

208 services207 patients

X-ray of hip, 2-3 views 73502

An X-ray of the hip with 2-3 views is a non-invasive imaging test. It uses a small amount of radiation to produce pictures of the hip joint. These images help in diagnosing conditions like fractures, arthritis, or other abnormalities. The process is quick and painless.

162 services153 patients

Ct scan of upper spine without contrast 72125

A CT scan of the upper spine without contrast is a non-invasive imaging test that uses X-rays to capture detailed images of your neck and upper back. It helps in identifying issues like fractures, tumors, or infections. No dye (contrast) is used in this scan.

150 services150 patients

X-ray of shoulder, minimum of 2 views 73030

An X-ray of the shoulder, with a minimum of 2 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of your shoulder bones. This helps in diagnosing conditions like fractures, arthritis, or other abnormalities. The procedure is quick and painless.

150 services128 patients

Ct scan of chest without contrast 71250

A CT scan of the chest without contrast is a non-invasive imaging procedure. It uses special X-ray equipment to produce detailed images of your chest area, including your lungs and heart. It can help diagnose conditions such as lung diseases or heart disorders. It doesn't involve any dyes or contrast agents.

135 services131 patients

Ct scan of blood vessels of chest with contrast 71275

A CT scan of the chest with contrast is a non-invasive imaging test. It uses X-rays and a special dye to get detailed images of your blood vessels in the chest. This helps in diagnosing conditions related to heart and lungs.

121 services120 patients

Ct scan of blood vessels of neck with contrast 70498

A CT scan of the neck's blood vessels with contrast is a diagnostic procedure. It uses X-rays and a special dye to create detailed images of your neck's blood vessels. This helps doctors detect issues such as blockages or abnormalities.

100 services100 patients

Complete ultrasound scan of abdomen 76700

A complete ultrasound scan of the abdomen is a non-invasive imaging procedure. It uses sound waves to produce images of the organs in your abdomen, such as the liver, gallbladder, spleen, pancreas, and kidneys. It helps in diagnosing, monitoring, and planning treatments.

100 services99 patients

Ct scan of blood vessels of head with contrast 70496

A CT scan of the head's blood vessels with contrast is a diagnostic procedure. A special dye (contrast) is injected into your body to make the blood vessels visible on the scan. This helps identify issues like blockages or abnormalities in your head's blood vessels.

99 services99 patients

X-ray of knee, 4 or more views 73564

An X-ray of the knee, 4 or more views, is a non-invasive imaging test. It involves capturing multiple images of your knee from different angles. This helps in diagnosing conditions such as fractures, arthritis, or infections. The procedure is quick and painless.

95 services72 patients

X-ray of lower and sacral spine, 2-3 views 72100

An X-ray of the lower and sacral spine involves capturing images of your lower back area, including the tailbone. This procedure helps in identifying problems like fractures, infections, or deformities. 2-3 different angle views provide a comprehensive picture.

93 services92 patients

Ultrasound study of one arm or leg veins with compression and maneuvers 93971

This is a non-invasive procedure using sound waves to visualize veins in an arm or leg. It involves applying gentle pressure and performing certain movements. It helps identify any abnormal blood flow or clots, ensuring vascular health.

93 services93 patients

Ct scan of chest with contrast 71260

A CT scan of the chest with contrast is an imaging procedure. A special dye (contrast) is used to highlight specific areas in your body, providing clearer pictures of your chest. This helps in diagnosing conditions related to your lungs, heart, and other chest structures.

92 services89 patients

Mri scan of brain without contrast 70551

An MRI scan of the brain without contrast is a non-invasive imaging test. It uses a magnetic field and radio waves to create detailed images of your brain. It helps in detecting abnormalities like tumors, stroke, inflammation, or infection.

90 services90 patients

Dxa bone density measurement of hip, pelvis, spine 77080

A DXA bone density measurement is a simple, quick, and non-invasive procedure that assesses the strength of your bones. This test uses X-rays to measure the amount of minerals, mainly calcium, in the hip, pelvis, and spine. It helps in early detection of osteoporosis or other bone diseases.

88 services88 patients

Complete ultrasound scan behind abdominal cavity 76770

A complete ultrasound scan behind the abdominal cavity is a non-invasive imaging procedure. It uses sound waves to create pictures of the structures and organs located at the back of your abdomen. It helps in diagnosing health conditions and monitoring ongoing treatments.

82 services82 patients

X-ray of knee, 3 views 73562

An X-ray of the knee, 3 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of the knee from three different angles. This helps medical professionals to diagnose and monitor conditions like arthritis, fractures, or infections. The process is quick and painless.

81 services64 patients

Mri scan of lower spinal canal without contrast 72148

An MRI scan of the lower spinal canal without contrast is a non-invasive imaging test. It uses a magnetic field and radio waves to produce detailed images of your lower spine. This helps identify issues like disc problems, tumors, or nerve conditions. No dye is used.

79 services78 patients

Ct scan of abdomen and pelvis without contrast 74176

A CT scan of the abdomen and pelvis is a non-invasive medical test. It uses special X-ray equipment to create detailed images of your abdominal and pelvic areas. This helps doctors examine organs, tissues, and vessels. No contrast dye is used in this procedure.

79 services76 patients

X-ray of foot, minimum of 3 views 73630

An X-ray of the foot, minimum of 3 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of the bones and tissues in your foot. This helps to identify fractures, infections, or other abnormalities. Multiple views ensure a comprehensive examination.

75 services65 patients

Ultrasound scan of head and neck soft tissue 76536

An ultrasound scan of the head and neck soft tissue is a non-invasive procedure that uses sound waves to create images of the soft tissues in these areas. It helps identify any abnormalities or issues, such as tumors, cysts, or infections. It's painless and doesn't involve radiation.

70 services70 patients

X-ray of abdomen, 1 view 74018

An X-ray of the abdomen, 1 view, is a quick and painless imaging test. It uses a small amount of radiation to produce images of the structures in your abdomen, such as the stomach, liver, and intestines. This can help identify issues like blockages, infections, or injuries.

67 services62 patients

X-ray of hand, minimum of 3 views 73130

An X-ray of the hand, minimum of 3 views, is a non-invasive imaging test. It uses a small amount of radiation to produce images of the bones in your hand from different angles. This helps in diagnosing fractures, infections, arthritis, or other abnormalities. It's quick and painless.

61 services53 patients

X-ray of wrist, minimum of 3 views 73110

An X-ray of the wrist, minimum of 3 views, is a diagnostic procedure that uses radiation to create images of your wrist from different angles. This helps detect fractures, infections, or other abnormalities for accurate diagnosis and treatment planning.

60 services55 patients

X-ray of ankle, minimum of 3 views 73610

An ankle X-ray is a quick, painless imaging test. It involves capturing at least three different images or 'views' of your ankle using small amounts of radiation. These images help identify any abnormalities or injuries, such as fractures or arthritis.

58 services54 patients

X-ray of knee, 3 views 73562

57 services46 patients

Ultrasound study of arm or leg veins with compression and maneuvers 93970

An ultrasound study of arm or leg veins with compression and maneuvers is a non-invasive procedure that uses sound waves to create images of your veins. This helps identify blood clots or other vein problems. During the procedure, pressure is applied to the veins and certain movements are performed to assess blood flow.

57 services57 patients

Mri scan of upper spinal canal without contrast 72141

An MRI scan of the upper spinal canal without contrast is a non-invasive imaging test. It uses a magnetic field and radio waves to create detailed images of your upper spine. This helps doctors identify issues such as injuries, infections or diseases. No dye is used.

54 services54 patients

Use of a drug to induce depression of consciousness by physician performing a procedure (5 years or older), initial 15 minutes 99152

This procedure involves a doctor administering a medication to reduce your consciousness during a procedure. This helps in managing discomfort and anxiety. The initial application lasts for 15 minutes and is for individuals aged 5 years or older.

53 services51 patients

X-ray of foot, minimum of 3 views 73630

52 services35 patients

X-ray of pelvis, 1-2 views 72170

An X-ray of the pelvis, 1-2 views, is a quick and painless imaging test. It uses a small amount of radiation to produce images of the lower part of your torso. These images help to detect any abnormalities or injuries in your hip bones and surrounding structures.

50 services50 patients

X-ray of lower and sacral spine, minimum of 4 views 72110

An X-ray of the lower and sacral spine involves capturing images of your lower back and tailbone area. It helps in identifying issues like fractures, arthritis, or other abnormalities. At least four different angles or 'views' are taken to get a comprehensive picture.

49 services48 patients

X-ray of hip, 2-3 views 73502

47 services47 patients

X-ray of knee, 1-2 views 73560

An X-ray of the knee with 1-2 views is a quick, painless test that produces images of the knee bones. It helps identify fractures, infections, or changes in the knee joint. During the procedure, you'll be asked to stay still while the X-ray machine captures the images.

46 services32 patients

Ct scan of face without contrast 70486

A CT scan of the face without contrast is a non-invasive imaging procedure. It uses X-rays to create detailed pictures of your face, including bones, soft tissues, and blood vessels. It's often used to diagnose diseases, injuries, or abnormalities. No contrast dye is used in this procedure.

45 services45 patients

X-ray of shoulder, minimum of 2 views 73030

45 services37 patients

X-ray of wrist, minimum of 3 views 73110

45 services37 patients

X-ray of hand, minimum of 3 views 73130

43 services31 patients

Ultrasound scan of uterus, ovaries, tubes, cervix and pelvic area through vagina 76830

An ultrasound scan of the lower abdominal region is a safe, non-invasive procedure that uses sound waves to create images of internal structures. This helps in checking the health of reproductive organs and detecting any abnormalities. The scan is done via a small probe inserted into the body.

43 services40 patients

Complete ultrasound scan of pelvis 76856

A complete ultrasound scan of the pelvis is a safe, non-invasive imaging procedure. It uses sound waves to create pictures of your lower abdomen area, helping doctors to evaluate and diagnose any potential issues. It's painless and usually takes about 30 minutes.

43 services40 patients

Ct scan of lower spine without contrast 72131

A CT scan of the lower spine without contrast is a non-invasive imaging test. It uses X-rays to create detailed images of your lower back area, helping to detect conditions like fractures, infections, or tumors. It's painless and generally quick.

42 services41 patients

X-ray of lower and sacral spine, minimum of 4 views 72110

41 services41 patients

X-ray of knee, 4 or more views 73564

41 services32 patients

X-ray of elbow, minimum of 3 views 73080

An elbow X-ray with a minimum of 3 views is a non-invasive imaging test. It helps visualize the bones of the elbow from different angles. This aids in diagnosing conditions like fractures or arthritis. The procedure is quick, painless, and usually takes around 15 minutes.

37 services35 patients

Ultrasound of both sides of head and neck blood flow 93880

An ultrasound of the head and neck blood flow is a safe, non-invasive procedure that uses sound waves to create images of blood vessels. It helps detect abnormalities like blockages or clots, ensuring optimal blood flow.

37 services37 patients

Ct guidance for insertion of radiation therapy fields 77014

CT guidance for insertion of radiation therapy fields involves using a CT scan to accurately map the area of your body where radiation will be applied. This ensures the radiation targets only the necessary area, minimizing impact to healthy tissues.

35 services34 patients

Diagnostic digital breast tomosynthesis, unilateral or bilateral (list separately in addition to 77065 or 77066) G0279

Diagnostic digital breast tomosynthesis is a 3D imaging test that allows doctors to examine your breast tissue layer by layer. It's performed on one or both sides. It helps in detecting abnormalities more accurately. It's often done in addition to other tests.

35 services35 patients

Ct scan of blood vessels of abdomen and pelvis with contrast 74174

A CT scan of the abdomen and pelvis with contrast is a medical imaging procedure. A special dye, called contrast, is used to make blood vessels more visible. The scan produces detailed images of your abdomen and pelvis, helping doctors to diagnose conditions or plan treatments.

34 services34 patients

Mri scan of brain before and after contrast 70553

An MRI scan of the brain, both before and after contrast, helps visualize different brain structures. Initially, images are taken without a contrast agent. Then, a safe dye is injected which helps highlight certain areas, providing clearer, more detailed images.

33 services33 patients

X-ray of chest, 2 views 71046

32 services32 patients

X-ray of upper spine, 2-3 views 72040

An X-ray of the upper spine, with 2-3 views, is a painless procedure that employs a small amount of radiation to capture images of your neck and upper back. It assists in diagnosing conditions like arthritis, fractures, or spinal deformities.

30 services30 patients

Limited ultrasound scan of 1 breast 76642

A limited ultrasound scan of one breast is a non-invasive imaging test. It uses sound waves to create pictures of the inside of your breast. It helps identify any unusual growths or changes. It's safe, quick, and typically painless.

29 services29 patients

X-ray of upper spine, 4-5 views 72050

An X-ray of the upper spine with 4-5 views is a non-invasive imaging test. It uses radiation to capture detailed images of the bones and structures in your neck and upper back. This procedure helps identify issues like fractures, infections, or deformities.

28 services28 patients

X-ray of hip, 1 view 73501

An X-ray of the hip, 1 view, is a quick, painless test where a small amount of radiation is used to produce images of the hip joint. This helps in diagnosing conditions like arthritis or fractures. You'll be positioned so that the X-ray machine can capture the best image of your hip.

28 services27 patients

X-ray of lower and sacral spine, 2-3 views 72100

27 services26 patients

X-ray of entire middle and lower spine, 2-3 views 72082

An X-ray of your middle and lower spine involves capturing images of these areas to identify any abnormalities. The procedure involves taking 2-3 different views for a comprehensive understanding. It's non-invasive and usually painless, helping doctors diagnose conditions like fractures or infections.

26 services25 patients

Mri scan of both breasts 77049

An MRI scan of both breasts is a non-invasive procedure using magnetic fields and radio waves to create detailed images of your chest area. This aids in detecting any abnormalities, ensuring your health and well-being.

26 services26 patients

X-ray of ankle, minimum of 3 views 73610

25 services22 patients

Ct scan of leg without contrast 73700

A CT scan of the leg is a non-invasive imaging test that uses X-rays to capture detailed images of your leg's bones, muscles, and blood vessels. It doesn't use contrast dye and doesn't cause any pain. It helps in diagnosing injuries or diseases.

25 services25 patients

Ct scan of abdomen and pelvis before and after contrast 74178

A CT scan of your abdomen and pelvis with and without contrast helps visualize your internal organs better. Contrast is a special dye that improves the clarity of the images. It's taken orally or injected into your veins before the scan. The process is painless and quick.

25 services24 patients

X-ray of upper spine, 4-5 views 72050

24 services24 patients

X-ray of both hips, 3-4 views 73522

An X-ray of both hips with 3-4 views is a safe imaging procedure. It involves capturing multiple pictures of your hip joints from different angles. This helps in diagnosing conditions like arthritis or fractures. You'll need to stay still during the process for clear images.

24 services24 patients

Diagnostic mammography of 1 breast 77065

Diagnostic mammography of 1 breast is a detailed imaging test that allows doctors to closely examine a specific area in the breast. It's often used when a routine screening reveals an abnormality. This test can help identify any unusual changes or issues.

24 services21 patients

X-ray of middle spine, 2 views 72070

An X-ray of the middle spine, or thoracic spine, involves capturing two different images of the area. This non-invasive procedure uses small amounts of radiation to visualize the bones and tissues in your back, helping to identify any abnormalities or injuries.

22 services22 patients

X-ray of upper arm, minimum of 2 views 73060

An X-ray of the upper arm with a minimum of 2 views involves capturing images of your arm from different angles. This helps in assessing the bones and surrounding tissues for any abnormalities or injuries. It's a quick, painless procedure.

22 services20 patients

Aspiration of fluid from chest cavity using imaging guidance 32555

This procedure, known as a thoracentesis, involves removing fluid from the space between the lungs and chest wall, called the pleural space. It's performed under imaging guidance to ensure precision. It can help diagnose conditions or relieve symptoms like shortness of breath.

21 services18 patients

Ct scan of arm without contrast 73200

A CT scan of the arm without contrast is a non-invasive imaging test. It uses X-ray technology to capture detailed images of your arm's structures. It doesn't involve any contrasting dye, hence, minimal preparation is required. It helps in diagnosing injuries or conditions affecting the arm.

21 services18 patients

X-ray of finger, minimum of 2 views 73140

An X-ray of the finger involves capturing images of your finger from at least two different angles. This non-invasive procedure helps in visualizing the bones and joints, aiding in the diagnosis of fractures, infections, or other abnormalities. Minimal discomfort may be experienced.

20 services20 patients

X-ray of lower leg, 2 views 73590

An X-ray of the lower leg, 2 views, is a quick, painless test that produces images of the bones in your lower leg. It helps to identify fractures, infections, or diseases. Two different angles are used to provide a comprehensive view of the leg's structure.

20 services19 patients

Insertion of tube for infusion with imaging guidance and review by radiologist, patient 5 years or older 36573

This procedure involves placing a tube into a vein for medication or fluid delivery. Imaging guidance helps ensure correct placement, while a radiologist reviews the process for safety. It's suitable for patients aged 5 and above.

19 services19 patients

X-ray of knee, 1-2 views 73560

19 services16 patients

X-ray of thigh bone, minimum 2 views 73552

An X-ray of the thigh bone is a non-invasive imaging test. It involves passing a small amount of radiation through the thigh to produce images of the bone structure. At least two different angles are captured for a comprehensive view. This helps detect fractures, infections, or other abnormalities.

18 services14 patients

Review by radiologist of ct guidance for needle placement 77012

This process involves a radiologist examining CT scan images to accurately guide a needle's placement within the body. This technique is often used for biopsies or treatments, ensuring precision and safety.

18 services18 patients

Diagnostic mammography of both breasts 77066

Diagnostic mammography involves using special imaging technology to capture detailed images of both breasts. This procedure helps in identifying any unusual changes or abnormalities. It's a crucial step in ensuring breast health and early detection of potential issues.

18 services18 patients

Mri scan of middle spinal canal without contrast 72146

An MRI scan of the middle spinal canal without contrast is a non-invasive imaging test. It uses magnetic fields and radio waves to create detailed images of your spine. This helps doctors identify any abnormalities or issues in your spinal canal. No dye is used in this procedure.

16 services15 patients

X-ray of both hips, 2 views 73521

An X-ray of both hips, 2 views, is an imaging test that uses a small amount of radiation to create detailed pictures of your hip joints. This procedure helps to detect fractures, infections, or other abnormalities in the hip area. Two different angles will be captured for a comprehensive assessment.

16 services16 patients

Dxa bone density measurement of forearm, finger, hand, or foot 77081

A DXA bone density measurement of the forearm, finger, hand, or foot is a non-invasive procedure that uses X-rays to measure the amount of calcium and other minerals in your bones. This test helps to assess the strength of your bones and your risk of fractures.

16 services16 patients

X-ray of ribs on side of body, minimum of 3 views 71101

This is a diagnostic procedure where a machine emits a small amount of radiation to capture images of your ribs from at least three different angles. It helps to identify issues like fractures or infections. It's a quick, painless process.

15 services15 patients

X-ray of elbow, minimum of 3 views 73080

15 services15 patients

Low dose ct scan of chest for lung cancer screening 71271

A low-dose CT scan of the chest is a quick, painless procedure that uses a small amount of radiation to create detailed images of your lungs. It's a key tool for early detection of lung cancer, especially for those at high risk.

14 services14 patients

Mri scan of lower spinal canal before and after contrast 72158

An MRI scan of the lower spinal canal with contrast is a non-invasive imaging procedure. It uses magnetic fields to generate detailed images of your lower spine. A contrast agent is injected to enhance these images, helping doctors see issues more clearly.

13 services13 patients

X-ray of forearm, 2 views 73090

An X-ray of the forearm, 2 views, is a diagnostic procedure where two different pictures of your forearm are taken using a small amount of radiation. These images help doctors assess your bone health and identify any fractures, infections, or other abnormalities.

13 services13 patients

Ultrasonic guidance for blood vessel access 76937

Ultrasonic guidance for blood vessel access is a medical procedure where sound waves are used to create images of your blood vessels. This helps doctors to accurately locate and access the vessels for treatments or tests, ensuring safety and precision.

13 services13 patients

Fluoroscopic guidance for insertion or removal of central vein access device 77001

Fluoroscopic guidance for central vein access device insertion or removal is a procedure where a special X-ray, called a fluoroscope, is used to help accurately place or remove a device in a central vein. This device aids in delivering medications or collecting blood samples.

13 services13 patients

Injection of anesthetic and/or steroid drug into sacral spine nerve root using imaging guidance, single level 64483

This procedure involves injecting a mix of numbing and anti-inflammatory medication into a specific nerve root in the lower back. It helps manage pain and reduce inflammation. The process is guided by imaging technology for precision.

12 services11 patients

X-ray of upper spine, 2-3 views 72040

12 services11 patients

X-ray of middle spine, 2 views 72070

12 services12 patients

X-ray of middle and lower spine, 2 views 72080

An X-ray of the middle and lower spine, or 2-view lumbar spine X-ray, involves capturing images of your back. This helps detect issues like fractures, infections, or other abnormalities. It's painless and quick, taking only a few minutes.

12 services11 patients

Mri scan of abdomen before and after contrast 74183

An MRI scan of the abdomen before and after contrast provides detailed images of your abdominal organs. Initially, images are taken without a contrast agent. Then, a safe dye is administered, usually via an IV, to highlight certain areas, giving a clearer picture to help diagnose various conditions.

12 services12 patients

Limited ultrasound scan of abdomen 76705

A limited ultrasound scan of the abdomen is a non-invasive imaging test. It uses sound waves to produce images of the abdominal organs such as the liver, gallbladder, spleen, pancreas, and kidneys. This helps to identify any abnormalities or issues.

12 services12 patients

Limited ultrasound scan of pelvis 76857

A limited ultrasound scan of the pelvis is a non-invasive imaging test. It uses high-frequency sound waves to create pictures of the lower abdomen area. This helps doctors view and assess the health of certain internal structures. It's painless and usually takes about 30 minutes.

12 services12 patients

Ultrasound scan of scrotum 76870

An ultrasound scan of the scrotum is a non-invasive imaging test. It uses sound waves to create pictures of the structures within the lower abdominal area. This helps to assess any discomfort or abnormalities you might be experiencing. The procedure is safe and painless.

12 services12 patients

Limited ultrasound scan of joint or other extremity structure except blood vessels 76882

A limited ultrasound scan of a joint or other extremity structure lacking blood vessels is a non-invasive procedure that uses sound waves to create images of the inside of your body. This helps in diagnosing and monitoring conditions related to your joints or other similar structures.

12 services11 patients

Ultrasonic guidance for needle placement 76942

Ultrasonic guidance for needle placement is a technique where sound waves create images that help accurately position the needle during procedures. This method ensures precision, minimizes discomfort, and increases safety.

12 services12 patients

Fine needle aspiration biopsy using ultrasound guidance, first growth 10005

Fine needle aspiration biopsy with ultrasound guidance is a procedure where a thin needle is inserted into a growth to extract a small sample. Ultrasound helps accurately locate the growth. This sample is then analyzed to determine the nature of the growth.

11 services11 patients

Ct scan of pelvis without contrast 72192

A CT scan of the pelvis without contrast is a non-invasive imaging test. It uses X-rays to create detailed pictures of your lower abdomen area. It helps in detecting issues like injuries, inflammation, or abnormal growths. It doesn't involve any dye injection.

11 services11 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 94904 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient

$104.67 typical visit price

range $69.07 – $202.63

Typical copayment $26.16 (range $17.26 – $50.65)

Most-billed visit code 99203

Established Patient

$85.00 typical visit price

range $23.44 – $166.64

Typical copayment $21.25 (range $5.86 – $41.66)

Most-billed visit code 99213

Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Medicare Quality Performance CMS QPP · MIPS

Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.

94.77/100

MIPS Final ScoreMerit-based Incentive Payment System · CMS Quality Payment Program

Scored as part of a group practice

Quality

93.84

Improvement Activities

Reported Quality Measures

Appropriate Follow-up Imaging for Incidental Abdominal Lesions

Percentage of final reports for abdominal imaging studies for asymptomatic patients aged 18 years and older with one or more of the following noted incidentally with follow_up imaging recommended: - Liver lesion =< 0.5 cm - Cystic kidney lesion < 1.0 cm -…

Lower rates are better for this measure.

76%74 patients

Radiation Consideration for Adult CT: Utilization of Dose Lowering Techniques

Percentage of final reports for patients aged 18 years and older undergoing CT with documentation that one or more of the following dose reduction techniques were used: - Automated exposure control - Adjustment of the mA and/or kV according to patient size -…

97%145 patients

Radiology: Reminder System for Screening Mammograms

Percentage of patients undergoing a screening mammogram whose information is entered into a reminder system with a target due date for the next mammogram

100%315 patients

Radiology: Stenosis Measurement in Carotid Imaging Reports

Percentage of final reports for carotid imaging studies (neck magnetic resonance angiography [MRA], neck computed tomography angiography [CTA], neck duplex ultrasound, carotid angiogram) performed that include direct or indirect reference to measurements of…

100%101 patients

Providers report different measures because they deliver different services; reporting more or less information is not a reflection of quality. Star ratings appear only where CMS assigned them.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

MESKEREM DABA RN, BSN

Registered Nurse (Psychiatric/Mental Health)

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 473-6666

ALEC CHANG D.O.

Psychiatry & Neurology (Psychiatry)

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 473-6835

MARIN HOSPITALIST MEDICAL GROUP, INC.

Internal Medicine

250 BON AIR RD, 3RD FLOOR
GREENBRAE, CA 94904

Marin County (415) 925-7545

DR. STEPHEN C ALLISON M.D.

Psychiatry & Neurology (Psychiatry)

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 925-7663

ANNIE LINN STODDARD

Rehabilitation Practitioner

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 473-6835

SARENA NAPIER ASW

Counselor (Mental Health)

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 473-6619

JULIET LIANNE HUNTINGTON CNM

Advanced Practice Midwife

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 925-7010

ZAMBIA RICHEA PLAYER RN

Registered Nurse

250 BON AIR RD
GREENBRAE, CA 94904

Marin County (415) 473-6666

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Ralph Koenker's NPI number?

The NPI number for Ralph Koenker is 1891734265. It was assigned to this individual provider in the NPPES registry on June 4, 2006.

Where is Ralph Koenker located?

Ralph Koenker practices at 250 Bon Air Rd, Greenbrae, CA 94904. The listed phone number is (415) 925-7000.

What is Ralph Koenker's specialty?

The primary specialty registered for this NPI is Radiology, specializing in Diagnostic Radiology, with taxonomy code 2085R0202X.

Is Ralph Koenker enrolled in Medicare?

Yes. Ralph Koenker is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organizations bill Medicare for Ralph Koenker's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Ralph Koenker reassigns Medicare benefits to 4 organizations: Prima Medical Foundation (Novato, CA), California Advanced Imaging Medical Associates Inc (San Francisco, CA), Regents Univ Of California Ucsf (San Francisco, CA) and Sutter Valley Medical Foundation (Fairfield, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Ralph Koenker's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Ralph Koenker was last updated on June 28, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.