with .net io function

$output = @()
$plineblank = $false
$tline = ''
$reader = [System.IO.File]::OpenText("C:\full\path\to\testfile.txt ")

while($null -ne ($line = $reader.ReadLine())) {
    if ($line -eq '' -and $pline -ne '' ){
        $output += $tline
        $tline = $null
    } else {
        $tline = $tline+"`n"+$line
    }
    $pline = $line
}
$output += $tline

$reader.Close()