CLT Vascular & Pigmented Lesion Treatment 2 — Questions and Answers
Question 1: Which chromophore is the primary target when treating port wine stains with pulsed dye laser?
- Melanin
- Oxyhemoglobin (Correct answer)
- Water
- Collagen
Correct answer: Oxyhemoglobin
Oxyhemoglobin in blood vessels absorbs the 585–595 nm wavelength of pulsed dye laser, making it the primary chromophore target for port wine stain treatment.
Question 2: A patient with Fitzpatrick skin type IV presents for treatment of solar lentigines. Which approach best minimizes dyspigmentation risk?
- Use maximum fluence with a single pass
- Use a Q-switched Nd:YAG at 1064 nm with conservative settings (Correct answer)
- Use intense pulsed light at high energy
- Apply alexandrite laser at standard fluence
Correct answer: Use a Q-switched Nd:YAG at 1064 nm with conservative settings
The 1064 nm Nd:YAG has less affinity for epidermal melanin, reducing the risk of post-inflammatory hyperpigmentation in darker skin types.
Question 3: What is the term for the thermal relaxation time of a target chromophore?
- The time light takes to reach the target
- The time required for the target to cool to half its peak temperature (Correct answer)
- The pulse duration needed to destroy the target
- The interval between laser pulses
Correct answer: The time required for the target to cool to half its peak temperature
Thermal relaxation time (TRT) is defined as the time required for the target tissue to dissipate 50% of its absorbed heat after laser exposure.
Question 4: During treatment of telangiectasias on the nose, the patient reports immediate darkening of the vessel followed by disappearance. This response indicates:
- Insufficient fluence was delivered
- Epidermal damage has occurred
- Successful photothermocoagulation of the vessel (Correct answer)
- Laser-induced purpura requiring retreatment
Correct answer: Successful photothermocoagulation of the vessel
Immediate vessel darkening (hemoglobin denaturation) followed by disappearance is the desired clinical endpoint for successful telangiectasia coagulation.
Question 5: Which wavelength is most selective for superficial dermal melanin pigmentation in seborrheic keratoses?
- 1064 nm
- 810 nm
- 532 nm (Correct answer)
- 1320 nm
Correct answer: 532 nm
The 532 nm wavelength (KTP or frequency-doubled Nd:YAG) is highly absorbed by melanin and targets superficial pigmented lesions effectively.
Question 6: A purpuric response after pulsed dye laser treatment of a hemangioma is considered:
- A complication requiring immediate intervention
- An expected clinical endpoint at appropriate fluences (Correct answer)
- Evidence of epidermal necrosis
- A sign of insufficient energy delivery
Correct answer: An expected clinical endpoint at appropriate fluences
Purpura after PDL treatment indicates red blood cell extravasation from coagulated vessels and is an expected clinical endpoint at therapeutic fluences.
Question 7: When treating café-au-lait macules, which factor most predicts a poor response to laser treatment?
- Lesion location on the trunk
- Presence of giant melanosomes histologically (Correct answer)
- Patient age under 30
- Lesion diameter over 5 cm
Correct answer: Presence of giant melanosomes histologically
Giant melanosomes in café-au-lait macules are associated with poorer laser treatment response and higher recurrence rates.
CLT Vascular & Pigmented Lesion Treatment 2
Which chromophore is the primary target when treating port wine stains with pulsed dye laser?