Theodoor D. Witkamp

Perimesencephalic Hemorrhage Exclusion of Vertebrobasilar Aneurysms With CT Angiography

BACKGROUND AND PURPOSE It is important to recognize a perimesencephalic pattern of hemorrhage in patients with subarachnoid hemorrhage (SAH), because in 95% of these patients the cause is nonaneurysmal and the prognosis is excellent. The purpose of this study was to investigate whether CT angiography can accurately exclude vertebrobasilar aneurysms in patients with perimesencephalic patterns of hemorrhage and therefore replace digital subtraction angiography (DSA) in this setting. METHODS In 40 patients with posterior fossa SAH as shown on unenhanced CT, 2 radiologists independently evaluated unenhanced CT for distinguishing between perimesencephalic and nonperimesencephalic pattern of hemorrhage and assessed CT angiography for detection of aneurysms. All patients subsequently underwent DSA or autopsy. RESULTS Observers agreed in 38 of 40 patients (95%) in differentiating perimesencephalic and nonperimesencephalic patterns of hemorrhage on unenhanced CT. On the CT angiograms, both observers detected a vertebrobasilar aneurysm in 16 patients and no aneurysm in 24 patients. These findings were confirmed by DSA or autopsy. No patients with a perimesencephalic pattern of hemorrhage were found to have an aneurysm on either CT angiography or DSA. CONCLUSIONS Good recognition of a perimesencephalic pattern of hemorrhage is possible on unenhanced CT, and CT angiography accurately excludes and detects vertebrobasilar aneurysms. DSA can be withheld in patients with a perimesencephalic pattern of hemorrhage and negative CT angiography.

New Detected Aneurysms on Follow-Up Screening in Patients With Previously Clipped Intracranial Aneurysms Comparison With DSA or CTA at the Time of SAH

Background and Purpose— Patients with a history of aneurysmal subarachnoid hemorrhage may have aneurysms on screening several years after the hemorrhage. For determining the benefits of follow-up screening, it is important to know whether these aneurysms have developed after the hemorrhage or are visible in retrospect, and if so, whether the size has increased. Methods— Aneurysms were categorized into de novo aneurysms and aneurysms visible in retrospect (already present) with increased or stable size. We studied aneurysm characteristics for these 3 categories: the relation between aneurysm development or enlargement and duration of follow up and the relation between enlargement and initial size of the aneurysm. Results— In 87 of 495 patients (17.6%), aneurysms were detected; for 51 of these patients with 62 aneurysms, the original catheter or computed tomographic angiogram was available for comparison. Of the 62 aneurysms, 19 were de novo and 43 were visible in retrospect, 10 with increased size and 33 with stable size. De novo aneurysms were mainly ≤5 mm (95%) and located at the middle cerebral artery (63%). For aneurysms visible in retrospect, the most frequent location was the posterior communicating artery (21%). There was no relation between the development of de novo aneurysms or enlargement and the duration of follow-up or between enlargement and the initial size of the aneurysm. Conclusions— Of aneurysms detected at screening, one third were de novo and two thirds were missed at the time of the initial hemorrhage. One quarter of initially small aneurysms had enlarged during follow-up.

Is joint effusion on MRI specific for haemophilia

Magnetic resonance imaging (MRI) scores for haemophilic arthropathy are useful for evaluation of early and moderate arthropathy. The most recent additive International Prophylaxis Study Group (IPSG) MRI scale for haemophilic arthropathy includes joint effusion. However, it is unknown whether joint effusion is haemophilia specific. Correct interpretation of joint effusion is needed for outcome assessment of prophylactic therapies in haemophilia care. The aim of this study was to compare joint effusion on MRI between young adults with haemophilia and healthy controls. MRIs of both knees and ankles of 26 haemophilic patients (104 joints) and 30 healthy active men (120 joints) were assessed. Scans in both groups were performed in 2009/2010 and 2012 respectively. Joint effusion was measured and scored according to the MRI atlas referred by the IPSG MRI scale for haemophilic arthropathy. Median age of haemophilic patients and healthy controls was 21 and 24 years respectively. In haemophilic patients 23% of knees and 22% of ankles showed joint effusion. Healthy controls had significantly more positive scores for knee effusion (67%, P < 0.01) and a comparable scores for effusion in the ankle (17%). Joint effusion according to criteria of the IPSG MRI scale was observed significantly more often in knees of healthy controls, while findings in ankles were similar. These data suggest that joint effusion in knees and ankles is not haemophilia specific. Inclusion of joint effusion in the MRI scale is expected to reduce its specificity for haemophilic arthropathy.

Assessment of the preferred plane and sequence in the depiction of mesial temporal sclerosis using magnetic resonance imaging.

RATIONALE AND OBJECTIVES Definition of optimal magnetic resonance (MR) scanning plane and conventional MR sequence for the detection of mesial temporal sclerosis (MTS). METHODS Coronal and axial T2-weighted images and axial T2-weighted images parallel to the long axis of the hippocampus (APLAH) and coronal inversion recovery (IR) images were obtained in patients with medically intractable temporal lobe epilepsy in their phase 1 preoperative evaluation. Thirty-three consecutive MR scans were reviewed by a panel of three radiologists. Twenty-three patients had MR abnormalities consistent with MTS, and ten scans were normal. To assess the best single scanning technique, another group of three radiologists, who were masked to all patient data, individually assessed the different planes and sequences of the 33 studies presented separately in a random fashion. For each plane and sequence, the likelihood (L) ratio for the correct diagnosis was determined separately. RESULTS For all planes considered separately, a likelihood ratio of 4.4 was optimal for the coronal T2-weighted images. The likelihood ratio of APLAH T2 was 2.2; of axial T2, 3.9; of coronal IR, indefinite because of 100% specificity. CONCLUSIONS For the assessment of MTS, coronal T2-weighted images were considered the best single scanning technique.