Michiel A. M. Feldberg

Magnetic resonance imaging of the brachial plexus in patients with multifocal motor neuropathy

We studied whether magnetic resonance (MR) imaging of the brachial plexus is useful to distinguish multifocal motor neuropathy (MMN) from lower motor neuron disease (LMND) and whether abnormalities resemble those of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We compared MR images of the brachial plexus of nine patients with MMN with scans from five patients with CIDP, eight patients with LMND, and 174 controls. In two patients with MMN, and in three patients with CIDP, the MR images showed an increased signal intensity on the T2-weighted images of the brachial plexus. Two other patients with MMN demonstrated a more focal, increased signal intensity on the T2-weighted images, occurring in one patient only in the axilla, and in the other patient in the axilla and in the ventral rami of the roots. MR images of the brachial plexus of eight patients with LMND were normal. The distribution of the MR imaging abnormalities corresponded with the distribution of symptoms of the patients: asymmetrical in MMN and symmetrical in CIDP. These findings demonstrate that MR imaging abnormalities of the brachial plexus in patients with MMN resemble those seen in CIDP and may be useful to distinguish MMN from LMND.

A rational approach to dose reduction in CT: individualized scan protocols

The aim of this study was to demonstrate that dose reduction and constant image quality can be achieved by adjusting X-ray dose to patient size. To establish the relation between patient size, image quality and dose we scanned 19 patients with reduced dose. Image noise was measured. Four radiologists scored image quality subjectively, whereby a higher score meant less image quality. A reference patient diameter was determined for which the dose was just sufficient. Then 22 patients were scanned with the X-ray dose adjusted to their size. Again, image noise was measured and subjective image quality was scored. The dose reduction compared with the standard protocol was calculated. In the first group the measured noise was correlated to the patient diameter (ρ=0.78). This correlation is lost in the second group (ρ=–0.13). The correlation between patient diameter and subjective image quality scores changes from ρ=0.60 (group 1) to ρ=–0.69 (group 2). Compared with the standard protocol, the dose was reduced (mean 28%, range 0–76%) in 19 of 22 patients (86%). Dose reduction and constant noise can be achieved when the X-ray dose is adjusted to the patient diameter. With constant image noise the subjective image quality increases with larger patients.

Grey Turner's sign and Cullen's sign in acute pancreatitis

Four patients with acute pancreatitis presenting with Grey Turners sign or Cullens sign have been studied by computed tomography (CT). These observations help confirm the precise anatomic pathways by which the extravasated pancreatic enzymes and their effects lead to these cutaneous discolorations.Grey Turners sign is produced by spread from the anterior pararenal space to between the two leaves of the posterior renal fascia and subsequently to the lateral edge of the quadratus lumborum muscle. Communication may be established to the posterior pararenal space and to the structures of the flank wall. The lumbar triangle, a site of anatomic weakness on the flank wall, may serve as a structural predisposition.Cullens sign can be seen to be secondary to the tracking of liberated pancreatic enzymes to the anterior abdominal wall from the inflamed gastrohepatic ligament and across the falciform ligament. Another more direct pathway may be extension from inflammatory changes of the small mesentery or greater omentum to the round ligament, and then to properitoneal fat deep to the umbilicus.

Radiation-induced brachial plexopathy : MR imaging

Abstract Objective. To describe the MR imaging appearance of radiation-induced brachial plexopathy. Design. MR imaging was performed in two patients with the clinical diagnosis of radiation-induced brachial plexopathy and in one with surgically proven radiation fibrosis of the brachial plexus. Patients. Three patients who had had radiation therapy to the axilla and supraclavicular region (two with breast carcinoma and one with Hodgkin’s lymphoma) presented with symptoms in the arm and hand. To exclude metastases or tumor recurrence MR imaging was performed. Results and conclusion. In one patient, fibrosis showing low signal intensity was found, while in two patients high signal intensity fibrosis surrounding the brachial plexus was found on the T2-weighted images. In one case gadolinium enhancement of the fibrosis was seen 21 years after radiation therapy. It is concluded that radiation-induced brachial plexopathy can have different MR imaging appearances. We found that radiation fibrosis can have both low or high signal intensities on T2-weighted images, and that fibrosis can enhance even 21 years after radiation therapy.

Added value of CT criteria compared to the clinical SAP score in patients with acute pancreatitis

Abstract.Background: To assess the added value of established computed tomography (CT) scores versus the Simplified Acute Physiology (SAP) score in predicting outcome in patients with acute pancreatitis. Methods: Contrast-enhanced CT was performed in 45 patients with acute pancreatitis. The Balthazar score, CT severity index (CTSI), and Schröder score were assessed, and the SAP score was calculated. The predictive values of CT score and SAP score for mortality, need for one or more interventions, and length of hospital stay were compared. The added value of the SAP score to the CT scores was assessed by using ROC (receiver operating curve) analysis. Results: The positive predictive values of the higher Balthazar, CTSI, Schröder, and SAP scores, reflecting severe disease, were 50%, 41%, 41%, and 48%, respectively, for mortality, 85%, 84%, 84%, and 83%, respectively, for need for one or more interventions, and 55%, 66%, 66%, and 65%, respectively, for longer hospital stay. The negative predictive values of the lower Balthazar, CTSI, Schröder and SAP scores were 84%, 92%, 92%, and 42%, respectively, for mortality, 44%, 69%, 69%, and 45%, respectively, for need for one or more interventions, and 44%, 69%, 69%, and 55%, respectively, for longer hospital stay. When CT scores were added to the SAP score, there was no improvement in discriminating power for mortality. Conclusion: To identify patients with severe outcome, there is no clear benefit using established CT scores as opposed to the SAP score. However, the Balthazar score and CTSI are better than the SAP score in predicting a favorable outcome.

Preoperative staging of rectal cancer with computerized tomography. Accuracy, efficacy, and effect on patient management

Twenty‐three consecutive patients with rectal cancer were evaluated by pelvic computerized tomography (CT). The study was designed to assess the accuracy of preoperative CT staging. The results showed that the CT and surgical and/or pathologic staging agreed in 18 patients. In two patients, the pelvic extent was correctly assessed, but small liver implants were not recognized. In three patients, CT over‐estimated the extent of disease. The authors also studied whether or not CT yielded significant new information, which was not obtainable by other diagnostic methods. In most patients this was the case. Finally, the authors wanted to know the extent to which this knowledge influenced the decision about how to treat the patient. Computerized tomography findings influenced the treatment in less than 50% of the patients. It is concluded that the accuracy in staging, and the addition of new and unique information justified the routine use of CT prior to surgical intervention in all patients with known invasive rectal cancer.

Computed tomography in complicated acute appendicitis

Due to the position and length of the appendix, intraabdominal abscesses after perforation in complicated acute appendicitis may occur in several different and sometimes unsuspected anatomical locations. Five patients are described with proven complicated acute appendicitis and inflammatory processes in multiple sites: anterior pararenal space, general retroperitoneum, subcutaneous fat space, intraperitoneal cavity, and small bowel mesentery. A confusing case of ileocecal carcinoid with mesenteric involvement is also presented.In all cases complicated acute appendicitis was diagnosed on CT prior to surgery, except in 1 case in which a pelvic abscess developed after intramural cecal bleeding in a patient with hemophilia B.

PLANNING OF LIVER SURGERY USING THREE DIMENSIONAL IMAGING TECHNIQUES

In the simplified Couinaud classification, in which the liver is divided into eight segments, each supplied by a central vasculo-biliary sheath, little attention is given to the high prevalence of anatomical variations which occur, especially in the right hemiliver. Using volumetric acquisition techniques, such as magnetic resonance imaging or spiral computed tomography scanning, detailed insight into the individual segmental anatomy can now be obtained in a non-invasive manner. The significance of this anatomical insight lies in the planning of anatomical resections, whereby the relationship between tumour and individual segmental anatomy can be depicted in a three-dimensional format. As such, three dimensional (3D) liver imaging helps to design an individualised resection, tailored to the topographical relationship between individual segmental anatomy and tumour tissue present. Three dimensional liver imaging is of most practical value if a resection of one or more segments or sectors is considered, especially in the right hemiliver. In these cases, 3D liver imaging can demonstrate the precise location of the scissuras to the surgeon pre-operatively.

Massive bilateral non-Hodgkin’s lymphomas of the adrenals

Two cases of diffuse histiocytic lymphoma limited to both adrenals are described. Familiarity with these rare lesions will lead to a proper diagnostic approach.

PREOPERATIVE STAGING OF RECTAL CANCER WITH COMPUTERIZED TOMOGRAPHY

Twenty-three consecutive patients with rectal cancer were evaluated by pelvic computerized tomography (CT). The study was designed to assess the accuracy of preoperative CT staging. The results showed that the CT and surgical and/or pathologic staging agreed in 18 patients. In two patients, the pelvic extent was correctly assessed, but small liver implants were not recognized. In three patients, CT over-estimated the extent of disease. The authors also studied whether or not CT yielded significant new information, which was not obtainable by other diagnostic methods. In most patients this was the case. Finally, the authors wanted to know the extent to which this knowledge influenced the decision about how to treat the patient. Computerized tomography findings influenced the treatment in less than 50% of the patients. It is concluded that the accuracy in staging, and the addition of new and unique information justified the routine use of CT prior to surgical intervention in all patients with known invasive rectal cancer.