diff --git a/app/Models/Enums/StudyAccessFlags.php b/app/Models/Enums/StudyAccessFlags.php
index 6daf30d..df29ea0 100644
--- a/app/Models/Enums/StudyAccessFlags.php
+++ b/app/Models/Enums/StudyAccessFlags.php
@@ -8,8 +8,8 @@ enum StudyAccessFlags: int
 {
     use BitmaskFunctionality;
 
-    case None = 0;
-    case ViewPatientInfo = 1;
-    case ViewDicom = 1 << 1;
-    case ViewReports = 1 << 2;
+    case Forbidden = 0;
+    case ViewPatientInfo = 1 << 1;
+    case ViewDicom = 1 << 2;
+    case ViewReports = 1 << 3;
 }
diff --git a/app/Services/Pacs/OrthancRestClient.php b/app/Services/Pacs/OrthancRestClient.php
index cac5616..9330995 100644
--- a/app/Services/Pacs/OrthancRestClient.php
+++ b/app/Services/Pacs/OrthancRestClient.php
@@ -41,4 +41,9 @@ public function getStudies(): array
 
         return json_decode($response->getBody()->getContents(), true);
     }
+
+    public function getStudiesIds(): array
+    {
+        return json_decode($this->getClient()->get('/studies')->getBody()->getContents(), true);
+    }
 }
diff --git a/app/Services/Pacs/StudyImporter.php b/app/Services/Pacs/StudyImporter.php
index 2bc607b..e5a0a03 100644
--- a/app/Services/Pacs/StudyImporter.php
+++ b/app/Services/Pacs/StudyImporter.php
@@ -5,73 +5,156 @@
 use App\Models\Enums\StudyLevelStatus;
 use App\Models\Study;
 use Carbon\Carbon;
+use Illuminate\Support\Facades\DB;
 
 final class StudyImporter
 {
+    private array $study_ids = [];
+
+    private array $insert_queue = [];
+
+    private array $update_queue = [];
+
+    private OrthancRestClient $client;
+
+    public function __construct(?OrthancRestClient $client = null)
+    {
+        $this->client = $client ?? new OrthancRestClient;
+    }
+
     public function import(array $studies): void
     {
         foreach ($studies as $study) {
-            $orthanc_uid = strtolower($study['ID']);
-            $row = Study::where(compact('orthanc_uid'))->first();
-            if ($row != null) {
-                if ($row->study_status < StudyLevelStatus::StudyArrived) {
-                    // todo: update study
-                }
-
-                return;
-            }
-
-            $inst_name = data_get($study, 'MainDicomTags.InstitutionName');
-            $inst_id = InstituteMapper::map($inst_name);
-
-            $data = [
-                'orthanc_uid' => $orthanc_uid,
-                'is_locked' => false,
-                'is_active' => true,
-
-                'institution_name' => $inst_name,
-                'institute_id' => $inst_id,
-
-                'patient_uuid' => $study['ParentPatient'],
-                'patient_id' => data_get($study, 'PatientMainDicomTags.PatientID'),
-                'patient_name' => data_get($study, 'PatientMainDicomTags.PatientName'),
-                'patient_sex' => data_get($study, 'PatientMainDicomTags.PatientSex'),
-
-                'accession_number' => data_get($study, 'MainDicomTags.AccessionNumber'),
-                'referring_physician_name' => data_get($study, 'MainDicomTags.ReferringPhysicianName'),
-                'study_id' => data_get($study, 'MainDicomTags.StudyID'),
-                'study_instance_uid' => data_get($study, 'MainDicomTags.StudyInstanceUID'),
-                'study_date' => DicomUtils::dateTimeToCarbon($study['MainDicomTags']['StudyDate'], $study['MainDicomTags']['StudyTime']),
-                'receive_date' => Carbon::parse($study['LastUpdate'], 'UTC'),
-
-                'study_modality' => data_get($study, 'RequestedTags.Modality'),
-                'body_part_examined' => data_get($study, 'RequestedTags.BodyPartExamined'),
-                'software_versions' => data_get($study, 'RequestedTags.SoftwareVersions'),
-                'station_name' => data_get($study, 'RequestedTags.StationName'),
-                'operators_name' => data_get($study, 'RequestedTags.OperatorsName'),
-                'manufacturer' => data_get($study, 'RequestedTags.Manufacturer'),
-                'manufacturer_model_name' => data_get($study, 'RequestedTags.ManufacturerModelName'),
-
-                'series_count' => count($study['Series']),
-            ];
-
-            if ($study['IsStable']) {
-                $data['study_status'] = StudyLevelStatus::StudyArrived->value;
-            } else {
-                $data['study_status'] = StudyLevelStatus::Pending->value;
-            }
-
-            $dob = data_get($study, 'PatientMainDicomTags.PatientBirthDate');
-            if (trim($dob) != '') {
-                $data['patient_birthdate'] = Carbon::parse($dob);
-            }
-
-            $descr = data_get($study, 'MainDicomTags.StudyDescription');
-            if ($descr != null) {
-                $descr = data_get($study, 'RequestedTags.AcquisitionDeviceProcessingDescription');
-            }
-            $data['study_description'] = trim($descr);
-            Study::create($data);
+            $this->importStudy($study);
         }
     }
+
+    public function scanStudies()
+    {
+        $this->study_ids = $this->client->getStudiesIds();
+    }
+
+    private function checkUpdate(string $orthanc_uid): void
+    {
+        $row = DB::table('studies')->where('orthanc_uid', $orthanc_uid)->first(['id', 'study_status']);
+
+        if ($row == null) {
+            $this->insert_queue[] = $orthanc_uid;
+        }
+
+        if ($row->study_status < StudyLevelStatus::StudyArrived->value) {
+            $this->update_queue[$orthanc_uid] = $row->id;
+        }
+    }
+
+    public function filterStudies()
+    {
+        $this->insert_queue = [];
+        $this->update_queue = [];
+        foreach ($this->study_ids as $study_id) {
+            $this->checkUpdate($study_id);
+        }
+    }
+
+    private function fetchStudyDetails(string $orthanc_uid): ?array
+    {
+        $study = $this->client->getStudyDetails($orthanc_uid);
+        if ($study == null) {
+            return null;
+        }
+        $stats = $this->client->getStudyStatistics($orthanc_uid);
+        $study['Statistics'] = $stats;
+
+        return $study;
+    }
+
+    public function importStudies()
+    {
+        foreach ($this->update_queue as $orthanc_uid => $row_id) {
+            $study = $this->fetchStudyDetails($orthanc_uid);
+            if ($study == null) {
+                continue;
+            }
+            $this->updateStudy($row_id, $study);
+        }
+
+        foreach ($this->insert_queue as $orthanc_uid) {
+            $study = $this->fetchStudyDetails($orthanc_uid);
+            if ($study == null) {
+                continue;
+            }
+            $this->insertStudy($study);
+        }
+    }
+
+    private function prepareData(mixed $study): array
+    {
+        $inst_name = data_get($study, 'MainDicomTags.InstitutionName');
+        $inst_id = InstituteMapper::map($inst_name);
+
+        $data = [
+            'orthanc_uid' => strtolower($study['ID']),
+            'is_locked' => false,
+            'is_active' => true,
+
+            'institution_name' => $inst_name,
+            'institute_id' => $inst_id,
+
+            'patient_uuid' => $study['ParentPatient'],
+            'patient_id' => data_get($study, 'PatientMainDicomTags.PatientID'),
+            'patient_name' => data_get($study, 'PatientMainDicomTags.PatientName'),
+            'patient_sex' => data_get($study, 'PatientMainDicomTags.PatientSex'),
+
+            'accession_number' => data_get($study, 'MainDicomTags.AccessionNumber'),
+            'referring_physician_name' => data_get($study, 'MainDicomTags.ReferringPhysicianName'),
+            'study_id' => data_get($study, 'MainDicomTags.StudyID'),
+            'study_instance_uid' => data_get($study, 'MainDicomTags.StudyInstanceUID'),
+            'study_date' => DicomUtils::dateTimeToCarbon($study['MainDicomTags']['StudyDate'], $study['MainDicomTags']['StudyTime']),
+            'receive_date' => Carbon::parse($study['LastUpdate'], 'UTC'),
+
+            'study_modality' => data_get($study, 'RequestedTags.Modality'),
+            'body_part_examined' => data_get($study, 'RequestedTags.BodyPartExamined'),
+            'software_versions' => data_get($study, 'RequestedTags.SoftwareVersions'),
+            'station_name' => data_get($study, 'RequestedTags.StationName'),
+            'operators_name' => data_get($study, 'RequestedTags.OperatorsName'),
+            'manufacturer' => data_get($study, 'RequestedTags.Manufacturer'),
+            'manufacturer_model_name' => data_get($study, 'RequestedTags.ManufacturerModelName'),
+
+            'image_count' => data_get($study, 'Statistics.CountInstances'),
+            'series_count' => data_get($study, 'Statistics.CountSeries'),
+            'disk_size' => data_get($study, 'Statistics.DiskSize'),
+        ];
+
+        if ($study['IsStable']) {
+            $data['study_status'] = StudyLevelStatus::StudyArrived->value;
+        } else {
+            $data['study_status'] = StudyLevelStatus::Pending->value;
+        }
+
+        $dob = data_get($study, 'PatientMainDicomTags.PatientBirthDate');
+        if (trim($dob) != '') {
+            $data['patient_birthdate'] = Carbon::parse($dob);
+        }
+
+        $descr = data_get($study, 'MainDicomTags.StudyDescription');
+        if ($descr != null) {
+            $descr = data_get($study, 'RequestedTags.AcquisitionDeviceProcessingDescription');
+        }
+        $data['study_description'] = trim($descr);
+
+        return $data;
+    }
+
+    public function updateStudy(int $row_id, mixed $study): void
+    {
+        $data = $this->prepareData($study);
+        unset($data['orthanc_uid']);
+        Study::where('id', $row_id)->update($data);
+    }
+
+    public function insertStudy(mixed $study): void
+    {
+        $data = $this->prepareData($study);
+        Study::create($data);
+    }
 }
diff --git a/database/migrations/2024_12_27_060234_create_studies_table.php b/database/migrations/2024_12_27_060234_create_studies_table.php
index e00a6e9..c14d6ba 100644
--- a/database/migrations/2024_12_27_060234_create_studies_table.php
+++ b/database/migrations/2024_12_27_060234_create_studies_table.php
@@ -42,10 +42,10 @@ public function up(): void
             $table->dateTime('receive_date');
             $table->dateTime('report_date')->nullable();
             $table->foreignIdFor(Institute::class)->constrained()->onDelete('cascade');
-            $table->unsignedTinyInteger('study_status')->default(StudyLevelStatus::None->value);
+            $table->unsignedTinyInteger('study_status')->default(StudyLevelStatus::Pending->value);
             $table->unsignedTinyInteger('report_status')->default(ReportStatus::Pending->value);
 
-            $table->unsignedSmallInteger('image_count')->nullable(0);
+            $table->unsignedSmallInteger('image_count')->nullable();
             $table->unsignedSmallInteger('series_count')->nullable();
             $table->unsignedSmallInteger('disk_size')->nullable();
 
@@ -54,7 +54,7 @@ public function up(): void
             $table->foreignIdFor(User::class, 'referring_physician_id')->nullable()->constrained()->onDelete('set null');
             $table->foreignIdFor(User::class, 'reading_physician_id')->nullable()->constrained()->onDelete('set null');
 
-            $table->unsignedTinyInteger('access_flags')->default(StudyAccessFlags::None->value);
+            $table->unsignedTinyInteger('access_flags')->default(StudyAccessFlags::Forbidden->value);
             $table->string('access_password')->nullable();
             $table->timestamps();