Evaluation of metastatic brain Evaluation of metastatic brain lesions by intraoperative lesions by intraoperative ultrasonography (IOUS) ultrasonography (IOUS)

Mehdi Abouzari and Mehdi Abdollahzadeh Mehdi Abouzari and Mehdi Abdollahzadeh

Dr. Shariati Hospital, Tehran University of Dr. Shariati Hospital, Tehran University of Medical Sciences, Tehran, IranMedical Sciences, Tehran, Iran

IntroductionIntroduction

Brain metastases are the most common Brain metastases are the most common types of intracranial tumor encountered.types of intracranial tumor encountered.

The incidence of cerebral metastasis The incidence of cerebral metastasis ranges from 20 to 30% of patients with ranges from 20 to 30% of patients with systemic cancer, with about half being a systemic cancer, with about half being a single metastasis.single metastasis.

Intraoperative Ultrasonography Intraoperative Ultrasonography (IOUS)(IOUS)

Ultrasonography has been used as an Ultrasonography has been used as an intraoperative diagnostic tool since 1970.intraoperative diagnostic tool since 1970.

IOUS is a valuable method supplementing IOUS is a valuable method supplementing preoperative diagnostic procedures, preoperative diagnostic procedures, facilitating the localization of isomorphic facilitating the localization of isomorphic tumors, reducing brain traumatization and tumors, reducing brain traumatization and making possible control of radical removal making possible control of radical removal of the lesions. of the lesions.

Materials and MethodsMaterials and Methods

Inclusion criteria were:Inclusion criteria were: Single or multiple metastases detected on Single or multiple metastases detected on

CT scan and MRI of the brain.CT scan and MRI of the brain. A peripheral location, spherical shape, A peripheral location, spherical shape,

ring enhancement with prominent ring enhancement with prominent peritumoral edema, and multiple lesions, peritumoral edema, and multiple lesions, all suggest metastatic disease.all suggest metastatic disease.

All lesions were evaluated by using a All lesions were evaluated by using a Tosbee real-time ultrasound scanner. A 3- Tosbee real-time ultrasound scanner. A 3- MHz transducer was used. MHz transducer was used.

The tip of the transducer was placed The tip of the transducer was placed gently on the intact cranial dura and gently on the intact cranial dura and moved in the direction of the sagittal and moved in the direction of the sagittal and coronal planes. coronal planes.

Imagination partsImagination parts

Tumor location under the craniotomyTumor location under the craniotomy Margins from the perilesional brain tissueMargins from the perilesional brain tissue Internal configuration and echogenicityInternal configuration and echogenicity Changes in the peritumoral areaChanges in the peritumoral area Location of the neuroanatomical structures Location of the neuroanatomical structures

such as the ventricle, falx, and main such as the ventricle, falx, and main arteries to the border of the lesionsarteries to the border of the lesions

ResultsResults

A total of 50 consecutive patients with A total of 50 consecutive patients with metastatic brain lesions were included in metastatic brain lesions were included in this study. this study.

Male/Female: 27/23Male/Female: 27/23 Mean age: 56.5±24.7 yearsMean age: 56.5±24.7 years Range: 29-82 yearsRange: 29-82 years

Source of brain metastasisSource of brain metastasis

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

IOUS findingsIOUS findings

The ultrasonographic appearance of The ultrasonographic appearance of malignant cysts was as low echogenic malignant cysts was as low echogenic areas.areas.

Free necrotic particles and double density Free necrotic particles and double density were commonly present in malignant were commonly present in malignant cysts. cysts.

The solid component surrounding the The solid component surrounding the cysts was thick. cysts was thick.

The external surface of solid parts was The external surface of solid parts was regular but internal surfaces facing cysts regular but internal surfaces facing cysts were irregular. were irregular.

The most hypoechogenic part was The most hypoechogenic part was commonly located in the central portion. commonly located in the central portion.

IOUS characteristics of lesionsIOUS characteristics of lesions

Single or multiple necrosis with irregular Single or multiple necrosis with irregular internal wallinternal wall

Single or trabeculated cystic part with Single or trabeculated cystic part with very low echogenicityvery low echogenicity

Irregular contour with invasive growth Irregular contour with invasive growth patternpattern

Vasogenic edema with poor demarcation Vasogenic edema with poor demarcation lineline

IOUS of a metastatic lesionIOUS of a metastatic lesion

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

ConclusionsConclusions

IOUS is an excellent tool for localization of IOUS is an excellent tool for localization of metastatic brain lesions and for detailed metastatic brain lesions and for detailed description of their interior.description of their interior.

The contour of tumors, perilesional changes, the The contour of tumors, perilesional changes, the presence of cyst and necrosis and their details presence of cyst and necrosis and their details are the most important information. are the most important information.

Irregular border, necrotic parts, invasive growth Irregular border, necrotic parts, invasive growth pattern, and dense perilesional edema can all be pattern, and dense perilesional edema can all be attributed to malignancy. attributed to malignancy.