PowerPoint Presentation - Introduction

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Evaluation of metastatic brain lesions by
intraoperative ultrasonography (IOUS) Mehdi
Abouzari and Mehdi Abdollahzadeh Dr. Shariati
Hospital, Tehran University of Medical Sciences,
Tehran, Iran
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Introduction

• Brain metastases are the most common types of
  intracranial tumor encountered.
• The incidence of cerebral metastasis ranges from
  20 to 30 of patients with systemic cancer, with
  about half being a single metastasis.

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Intraoperative Ultrasonography (IOUS)

• Ultrasonography has been used as an
  intraoperative diagnostic tool since 1970.
• IOUS is a valuable method supplementing
  preoperative diagnostic procedures, facilitating
  the localization of isomorphic tumors, reducing
  brain traumatization and making possible control
  of radical removal of the lesions.

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Materials and Methods

• Inclusion criteria were
• Single or multiple metastases detected on CT scan
  and MRI of the brain.
• A peripheral location, spherical shape, ring
  enhancement with prominent peritumoral edema, and
  multiple lesions, all suggest metastatic disease.

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• All lesions were evaluated by using a Tosbee
  real-time ultrasound scanner. A 3- MHz transducer
  was used.
• The tip of the transducer was placed gently on
  the intact cranial dura and moved in the
  direction of the sagittal and coronal planes.

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Imagination parts

• Tumor location under the craniotomy
• Margins from the perilesional brain tissue
• Internal configuration and echogenicity
• Changes in the peritumoral area
• Location of the neuroanatomical structures such
  as the ventricle, falx, and main arteries to the
  border of the lesions

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Results

• A total of 50 consecutive patients with
  metastatic brain lesions were included in this
  study.
• Male/Female 27/23
• Mean age 56.524.7 years
• Range 29-82 years

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Source of brain metastasis

• Lung 12 (24)
• Breast 6 (12)
• Gastrointestinal tract 5 (10)
• Other 13 (26)
• Unknown 14 (28)

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IOUS findings

• The ultrasonographic appearance of malignant
  cysts was as low echogenic areas.
• Free necrotic particles and double density were
  commonly present in malignant cysts.

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• The solid component surrounding the cysts was
  thick.
• The external surface of solid parts was regular
  but internal surfaces facing cysts were
  irregular.
• The most hypoechogenic part was commonly located
  in the central portion.

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IOUS characteristics of lesions

• Single or multiple necrosis with irregular
  internal wall
• Single or trabeculated cystic part with very low
  echogenicity
• Irregular contour with invasive growth pattern
• Vasogenic edema with poor demarcation line

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IOUS of a metastatic lesion

• The lesions were surrounded by a first, very thin
  hypoechogenic zone. The second zone was a
  vasogenic edematous zone. The ultrasonographic
  appearance of this zone was hyperechogenic and
  was similar to that of solid tumor parts.

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Conclusions

• IOUS is an excellent tool for localization of
  metastatic brain lesions and for detailed
  description of their interior.
• The contour of tumors, perilesional changes, the
  presence of cyst and necrosis and their details
  are the most important information.
• Irregular border, necrotic parts, invasive growth
  pattern, and dense perilesional edema can all be
  attributed to malignancy.