Lasse Jyrkinen

Initial experience with a wireless personal digital assistant as a teleradiology terminal for reporting emergency computerized tomography scans

A new type of terminal device, a wireless personal digital assistant (PDA) based on a GSM digital cellular phone, was used to transmit computerized tomography scans of 21 patients to a neuroradiologist. All transmitted images were suitable for a preliminary consultation and in one case a final report could be made. In 18 cases the findings were compatible with the reference film reading performed later and in three cases there were minor differences of no clinical importance. Transmission of a single image lasted 1 min 30 s and the transmission of a complete brain scan (14 images) took on average 21 min. The total process of transmission and interpretation of a brain examination series took on average 40 min. In this pilot study the neuroradiologist gained essential information in 24% of the cases and beneficial information in 62%. The neuroradiologist considered that the image consultation saved a hospital visit in 15 cases (71%). Although PDA technology is at an early stage of development and has numerous limitations, it is likely that future technical improvements will allow easier clinical consultations for neurosurgeons and neurologists.

MRI-guided trephine biopsy and fine-needle aspiration in the diagnosis of bone lesions in low-field (0.23 T) MRI system using optical instrument tracking

Abstract. The purpose of this study was to evaluate the feasibility of MRI-guided bone biopsy with optical instrument tracking and evaluate advantage of combined fine-needle aspiration (FNA) with trephine biopsy. Twenty trephine bone biopsies and 13 FNAs were performed under MRI and CT guidance in 14 patients. Informed consent was obtained from all patients. The evaluation of diagnostic accuracy was achieved by comparing the histopathological and cytological diagnosis with current or final diagnosis made during 6-month clinical follow-up. A 0.23-T open MRI scanner with interventional tools (Outlook Proview, Marconi Medical Systems, Cleveland, Ohio) was used. A surface coil was used. For trephine biopsy MRI-compatible bone biopsy set (Daum medical, Schwerin, Germany) was used. The FNA was performed with MRI compatible 20-G needle (Cook, Bloomington, Ind.). The diagnostic accuracy of MRI-guided trephine biopsy was 95%. The FNA sample diagnosis concurred with the histological in 54%. Our results show that MRI guidance in bone biopsies is accurate and safe. It is comparable to CT-guided or open biopsy. The role of combined FNA with bone biopsies remains controversial.

Percutaneous MR‐guided discography in a low‐field system using optical instrument tracking: A feasibility study

To evaluate the feasibility of MRI‐guided discography with optical tracking.

MR-guided bone biopsy: Preliminary report of a new guiding method

To evaluate the feasibility of a new MR compatible optical tracking guided bone biopsy system.

A portable diagnostic workstation based on a Webpad: implementation and evaluation

A wireless hand-held Webpad device was used to review a sample set of cranial computerized tomography (CT) studies to assess its diagnostic capabilities and its feasibility as a portable diagnostic workstation for radiology. The data-set consisted of 30 head CT studies of emergency cases. Two neuroradiologists and a senior radiologist participated in the evaluation of the portable workstation. They used a Web-based viewer that we developed, which provided all the major functionalities required for radiological image review. The reported radiological findings and diagnoses were compared with a gold standard, comprising a set of diagnoses previously formulated by a consensus panel of radiologists who had reviewed the original studies. The diagnoses made using the Webpad were correct (no major discrepancies) in 82 out of 90 interpretations (91%), which is comparable to the accuracy reported in image review with a conventional radiological workstation. The average total working time per diagnosis was 5 min 25 s (range 2–12 min). The simplicity of use of the system and its low cost make it suitable for distributing radiological studies within hospital facilities.

High-Quality Volume Rendering Using Seed Filling in View Lattice

Immense amounts of computer power are involved in volumetric rendering. New algorithms and acceleration techniques have been developed during the last ten years with faster computer hardware. The two main paths that have been taken to visualise volumetric data are surface rendering and volume rendering.

Volume rendering using seed-filling acceleration: supporting cut planes by fast reseeding.

OBJECTIVE Seed filling in view lattice is a method for accelerating volume rendering. Our previously published results on using seed filling had the limitation that they did not support cut planes. Cut planes are one of the main advantages of using volume rendering over surface rendering. In this article we describe the seed-filling acceleration technique and propose two fast reseeding processes that may be performed for each frame. MATERIALS AND METHODS The reseeding process performs a connected component search on the cut plane within the volume data set. The amount of processing done by a connected component search algorithm is proportional to N(2), assuming the data set size is N(3). We implemented two connected component search algorithms: one for orthogonal cut planes and another for oblique cut planes. We measured the time taken by the cutting and estimated the effect on the rendering performance when the cut plane was moved interactively. RESULTS Our measurements show that rendering rates of several frames per second can be achieved with a 266-MHz Pentium II PC, even when the object is interactively modified with cut planes during the rendering. CONCLUSIONS We have shown that the seed-filling algorithm is also applicable in situations where the displayed data is modified interactively using cut planes or objects. Applications in this regard include, for example, computer-aided surgery systems, where the instrument may be used to interactively perform the simulated cut in the data set.