Page 17 - Best diagnosticians: TOP 339 doctors

Dr. Isik Okuyan is an obstetrics and gynecology specialist at Memorial Göztepe Hospital in Istanbul (2025–present). He previously worked at Şanlıurfa Training and Research Hospital (2023–2025). He completed his OB/GYN residency at SB University Istanbul Training and Research Hospital (2019–2023). He earned his MD from Mersin University (2011–2017).

His credentials include GESEA Level 1 in Gynecological Endoscopy (Marseille, 2024). He presented a video and a poster at the 33rd ESGE Congress (2024). He is a member of the Turkish Medical Association, the Turkish Society of Gynecology and Obstetrics, and ESGE. He took part in meetings from 2022 to 2025, including ISON and national gynecology congresses.

Dr. Berrak Beyoglu Oruc is a specialist in obstetrics, gynecology, and IVF at Memorial Göztepe Hospital (2025–). She previously worked at Bahçeşehir University Medical Park Göztepe Hospital and Ağrı Training and Research Hospital. She also served as a research physician in gynecologic oncology at Bologna University S. Orsola (2022).

Accreditations and key training include: Certified ART Clinical Training, American Hospital (2025); GESEA MIGS Level 1 – European Certified Minimal Invasive Gynaecological Surgeon (2024). She also completed the Harvard Women’s Health and Menopause Course (2025), ESGO ORSI Robotic Surgery (2022), ESGO Masterclass (2022), and TMFTP Second Trimester Ultrasound (2024).

Awards: First prize, oral presentation—Transperineal Ultrasonography in Predicting Operative Delivery (13th Maternal–Fetal Medicine and Perinatology Congress, 2023). Third prize—Aortic Dissections (2016). Memberships: ISUOG, ESGE, MIJID, TJOD.

Dr. Haluk Caglar Karakaya is a specialist in cardiovascular surgery at Memorial Göztepe Hospital in Istanbul (2025–). He previously worked as a specialist at the University of Health Sciences Sancaktepe Şehit Prof. Dr. İlhan Varank Training and Research Hospital (2022–2025). He completed residency training at the University of Health Sciences Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital and at Ankara University. He earned his MD from Hacettepe University (English program).

Professional memberships: European Society for Cardiothoracic Surgery (EACTS), European Society for Vascular Surgery (ESVS), Turkish Society of Cardiovascular Surgery, National Society of Vascular and Endovascular Surgery.

Continuing education: 27th European Vascular Course (2024); Cardiac Memorial Robotic/Minimally Invasive Cardiac Surgery Summit (2024); 18th Turkish Cardiovascular Surgery Congress (2024); 24th ASVS Congress (2023); TKDCD Endovascular Course (2023); “Grey Areas in Vascular Surgery” Symposium (2023); Basic and Advanced Doppler Ultrasonography Course (2023).

Dr. Hidayet Demir is a Cardiovascular Surgery Specialist at Memorial Göztepe Hospital (2025–). He previously served as an Assistant Professor at Okan University Hospital (2021–2025). He was also a specialist at Ağrı I. Ç. University Training and Research Hospital (2019–2021). Earlier, he worked at City Health Group as Medical Director and ECMO Specialist (2015–2018). He later served as CEO (2018–2025).

Education: MD, Istanbul University Cerrahpaşa (2007–2013). Cardiovascular Surgery residency, SBÜ Kartal Koşuyolu (2013–2019). Beating‑Heart Coronary Bypass observer, Royal Brompton & Harefield Hospital (2018).

Memberships: TKDCD, UVECD, Turkish Medical Association, ESVS, EACTS. Courses: MIRC 2017 (minimally invasive/robotic). UVECD & EVC 2017 Venous Workshop. European Vascular Course 2017: Open Abdominal Aortic Aneurysm Treatment. TKDCD advanced aortic surgery. ESVS aortic arch techniques.

Dr. Ahmet Ekmekci is a cardiology specialist at Memorial Göztepe Hospital in Istanbul, since 2025. He earned the title of Associate Professor of Cardiology (Doçent) in 2014.

He served as Chief Assistant in Cardiology at Dr. Siyami Ersek Training and Research Hospital in 2010. He completed his cardiology residency at the same hospital in 2009. He finished his internal medicine residency at the Istanbul Faculty of Medicine from 2002 to 2007. He received his MD from Istanbul University, Istanbul Faculty of Medicine, in 2002.

He is a member of the Turkish Society of Cardiology, the European Society of Cardiology, and the European Heart Failure Association (Gold Member). He is also a member of the Istanbul Internal Medicine Association, the Stem Cell and Cellular Therapies Association, the Istanbul Medical Chamber, and the Turkish Medical Association. He served on the Board of the Turkish Society of Cardiology Heart Failure Working Group in 2016.

Dr. Muslim Sahin is a cardiology specialist at Memorial Göztepe Hospital (2025–present). He previously worked at VM Medical Park Pendik Hospital (2018–2025), Kartal Koşuyolu High Specialty Training and Research Hospital (2010–2018), Kartal Yavuz Selim State Hospital (2007–2010), and Kayseri Military Hospital (2006–2007).

He completed his cardiology residency at Maltepe University Faculty of Medicine (2001–2005). He earned his MD from Istanbul University Cerrahpaşa Faculty of Medicine (1995–2001).

He is a member of the Turkish Medical Chamber, the Turkish Society of Cardiology, the EuroCTO Club, and the European Society of Cardiology. He has completed training in TAVI, MitraClip, and renal denervation.

Dr. Sabahattin Gunduz is a cardiologist at Memorial Göztepe Hospital (2025–present). He previously worked as a cardiology specialist at VM Medical Park Pendik Hospital (2018–2025). He also served at Kartal Koşuyolu Heart Hospital (2014–2018), Tuzla State Hospital (2012–2014), and Ümraniye Training and Research Hospital (2010–2012).

He is a Professor of Cardiology at Bahçeşehir University, Faculty of Medicine (2022). He became an Associate Professor at Istanbul Kartal Koşuyolu High Specialty Training and Research Hospital (2017). He completed his cardiology residency at the same institution (2005–2009). He earned his MD from Istanbul University (1999–2005).

Professional memberships: TTB, TKD, ESC, EAPCI, EACVI.

Dr. Tolga Sinan Guvenc is a cardiologist at Memorial Göztepe Hospital (2025–). He previously worked at VM Medical Park Pendik (2019–2025) and at Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital (2014–2018).

He has authored over 200 scientific articles and book chapters. He serves on the Editorial Board of Scientific Reports.

He is a Fellow of the ESC Heart Failure Association. He is also a member of the Turkish Society of Cardiology, the European Society of Cardiology, and Sigma Xi.

Advanced training includes a clinical fellowship in the Advanced Heart Failure Unit at the University of Alberta. He also served as a visiting scientist at the Echocardiography Station at the University of Alabama at Birmingham. Education: MD, Istanbul University Cerrahpaşa (English). Cardiology residency, Dr. Siyami Ersek.

Dr. Mehmet Semih is a cardiology specialist at Memorial Göztepe Hospital (2025–present). He previously served as a specialist at Koşuyolu High Specialty Training and Research Hospital (2024–2025) and Sivas Numune Hospital (2023–2024). He completed his cardiology residency at Istanbul University Cerrahpaşa (2018–2023). He earned his MD at Istanbul University (2006–2012).

He is a member of the Turkish Society of Cardiology, the European Society of Cardiology, and the European Heart Rhythm Association. He has delivered oral case presentations at EHRA and TKD congresses. He also completed the TKD Bifurcation Lesions Management Course and the TKD Echocardiography Symposium.

Dr. Ahmet Mutlu is an ENT specialist at Memorial Göztepe Hospital (2025–present). He holds European Board certification in ORL‑HNS (FEBORL‑HNS, 2018) and National ENT Board certification (2016). Education: MD, Kocaeli University (2011). ENT residency, Kocaeli University (2011–2016). Master’s in Audiology, Başkent University (2017).

Previous posts: Istanbul Medeniyet University (2019–2025). Üsküdar State Hospital (2016–2019). Kocaeli University (2011–2016). Training: Otology‑Neurotology School (2019–2020). Laryngology & Phoniatrics School (2021–2022). Portmann Institute microsurgery course (2013). Memberships: Turkish ORL‑HNS, Istanbul ENT Assoc., Otology‑Neurotology, Phoniatrics, Turkish Medical Association.

Psychiatrist at Memorial Bahçelievler Hospital since 2018. Previously worked at Medical Park Bahçelievler, Trakya University Psychiatry, and Bakırköy Mental Health. MD, Istanbul University Cerrahpaşa. Psychiatry residency at Bakırköy.

Author of 80 publications (53 national, 27 international). Has 330 international citations and 90 presentations. Wrote “Neurotransmitters and Depression” (1988). Contributed 25 book chapters and translated 3 psychiatry books.

Founding member of the Turkish Psychiatric Association and member of APA and ISPG. Awards include the TPA Research Encouragement (2006) and the Mood Disorders Third Prize (2004). Certified CBT psychotherapist (national and European, 2012) and supportive psychotherapist/instructor (2013). Supervised 21 theses. Was an invited speaker at more than 20 congresses and chaired 4. Served on 10 organizing committees. Reviewed 70 papers. Served on the editorial boards of 15 journals. Principal investigator or consultant on 5 projects.

Dr. Seo Seung-Il is the Department Head of Family Medicine. He also leads the Health Check-up Center at JIAn Health Screening Center.

He holds a Master’s in Medicine from Chonbuk National University Graduate School. He completed his internship at Jeju National University Hospital. He finished his Family Medicine residency at Boeun Sae-rim Hospital. There, he worked in the Internal Medicine Check-up Center and served as a Family Medicine instructor.

Accreditations: Regular Member, Korean Academy of Family Medicine. Qualified Specialist in Family Medicine Examination (KAFM). Regular Member, Korean Society of Hypertension. Certified Instructor in Hypertension Examination (KSH).

Assoc. Prof. Dr. Saydam Mehmet is a general surgeon at Lokman Hekim Istanbul Hospital (2025–present). His work covers oncologic, endocrine, and metabolic surgery. He performs laparoscopic surgery, including hernia repair and anti-reflux procedures. He also treats morbid obesity and type 2 diabetes. Sleeve gastrectomy is among his key procedures.

Education: He graduated from the Gülhane Military Medical Academy, Faculty of Medicine (1995–2001). He completed his general surgery residency there (2004–2009). He was a research fellow at the University of Miami/Jackson Memorial Hospital, Ryder Trauma Center (2015–2016).

Experience: He worked as a general surgery specialist at GATA Haydarpaşa, Girne Military, and Mevki Military. He later served as Associate Professor of General Surgery at Dışkapı, Sancaktepe, and Medical Park Gebze. Earlier, he practiced as a general practitioner in military medical services.

Dr. Fulya Gokdagli Sigir is an OB/GYN focused on reproductive medicine. She earned her MD from Istanbul University Cerrahpaşa in 2006. She completed her OB/GYN residency at Istanbul Medeniyet University from 2007 to 2013. During her training, she also completed an observership in perinatology at Frankfurt Bürger Hospital.

From 2013 to 2014, she fulfilled compulsory service at Batman Sason State Hospital. She then served as an Assistant Professor at Medipol Mega University Hospital from 2014 to 2017. Her work focused on obstetrics and gynecologic oncology.

She obtained certification in Assisted Reproductive Treatment Practices in 2017 at Memorial Şişli IVF Center. She then worked for about three years as an IVF specialist. At Kolan International Hospital – Şişli IVF Center, she worked from 2021 to 2025. She served as Responsible Physician from 2023 to 2025. She has been an Assistant Professor at Galata University since 2021. Her interests include IVF, IUI, reproductive endocrinology, endometriosis and adenomyosis, and laparoscopic and hysteroscopic surgery.