Contrast enhancement and quantitative signal analysis in MR imaging of multiple myeloma: assessment of focal and diffuse growth patterns in marrow correlated with biopsies and survival rates

OBJECTIVE: This study describes infiltration patterns of multiple myeloma in spinal MR imaging and correlates the findings with biopsies, survival rates, and signal intensity measurements in unenhanced and enhanced studies. MATERIALS AND METHODS: Fifty-three patients with multiple myeloma and 53 age-matched controls underwent MR imaging of the spine. Twenty-nine patients underwent sagittal T1-weighted spin-echo enhanced imaging and all patients underwent sagittal T1-weighted spin-echo unenhanced and opposed-phase gradient-recalled echo images, and signal intensity measurements were taken. MR imaging was correlated to marrow specimens (n = 40) and a clinical staging system. The probability of survival was also calculated. Finally, we performed qualitative visual evaluation (infiltration pattern, degree of tumor involvement) and a quantitative evaluation (marrow signal intensity ratios, contrast enhancement). RESULTS: Five infiltration patterns were found: normal-appearing marrow with low-grade interstitial infiltration (n = 5), focal (n = 18), diffuse (n = 12), focal and diffuse (n = 13), and salt-and-pepper (n = 5). Infiltration pattern correlated with clinical staging; all patients with normal-appearing and salt-and-pepper patterns were clinically stage I. Diffuse marrow infiltration was assessed by marrow ratios: low-grade infiltration, greater than 2.0; intermediate, 1.0-2.0; highgrade, less than 1.0. Contrast enhancement with a signal intensity increase greater than 40% indicated diffuse infiltration. In the control group, all of whom had no marrow disease, enhancement varied (mean +/- SD, 16% +/- 8.9%) but did not exceed 40%. Marrow involvement on MR images correlated significantly with clinical staging and survival (p < or = .001). CONCLUSION: MR imaging with opposed gradient-recalled echo sequences and contrast enhancement provided data that allowed us to classify infiltration patterns and to quantify diffuse marrow involvement in multiple myeloma, both of which correlated to clinical staging and biopsy. Also, the MR data was of prognostic value. Therefore, like laboratory parameters, biopsies, and radiographs, MR imaging can be a supporting pillar in staging and planning treatment of patients with multiple myeloma.     

Reduction of radioactive seed embolization to the lung following prostate brachytherapy

PURPOSE: To clarify the natural history of solitary plasmacytoma of bone (SBP) after radiation treatment. METHODS AND MATERIALS: Between 1965-1996, we identified 57 previously untreated patients with a SBP. A serum myeloma protein was present in 33 patients (58%) and Bence Jones proteinuria was present in an additional eight patients (14%). The median radiotherapy dose was 50 Gy (range, 30-70 Gy). Overall survival, cause-specific survival, and freedom from progression to multiple myeloma were calculated actuarially. RESULTS: Local control was achieved in 55 of 57 patients (96%). For those 29 patients (51%) who subsequently developed multiple myeloma, the median time to progression was 1.8 years. There was a direct correlation between persistence of abnormal protein following radiotherapy and the likelihood of developing multiple myeloma. Among 11 patients with disappearance of myeloma protein, only two developed multiple myeloma after 4 and 12 years, in contrast to progression in 57% of patients with a persistent protein peak and 63 % of those with nonsecretory disease (p = 0.02). Among 23 patients with thoracolumbar spine disease, 7 of 8 patients staged with plain radiographs alone developed multiple myeloma in comparison with 1 of 7 patients who also had magnetic resonance imaging (MRI) (p = 0.08). For all patients, the median survival from radiotherapy was 11.0 years. The median cause-specific survival of patients with disappearance of myeloma protein was significantly longer than that of the remaining patients (p = 0.004). CONCLUSION: Results supported the importance of precise staging that includes MRI of the spine for optimum patient selection and the application of definitive radiotherapy. Those patients with myeloma protein that disappears following radiotherapy represent a category with a high likelihood of cure.     

En bloc resections of bone tumors of the thoracolumbar spine. A preliminary report on 29 patients

STUDY DESIGN: Twenty-nine patients with primary bone tumors and solitary metastases of the thoracolumbar spine treated with en bloc resection are reviewed retrospectively. OBJECTIVE: To demonstrate the possibility to apply in the spine the same principles of surgical oncology adopted for primary bone tumors of the limbs. SUMMARY OF BACKGROUND DATA: The surgical oncologic staging systems currently applied in limb tumor surgery are difficult to apply to spinal tumors. The anatomic conditions make extralesional surgery difficult or impossible, which has restrained a more common use of resection surgery in the spine. Focus is put on a new surgical staging system and en bloc vertebral resection. METHODS: Twenty-five primary malignant and aggressive benign bone tumors and four solitary metastases were treated. The patients were submitted to oncologic and surgical staging for surgical planning. The primary tumors were classified according to Enneking system: three Stage IA, six Stage IB, eight Stage IIB, eight Stage 3 benign. Staging according to the Weinstein-Boriani-Biagini system was also done. Thirteen lesions involved the vertebral body; nine lesions developed in the posterior arch, or part of it, and seven lesions occupied part of the body and part of the arch. A careful anesthesiologic evaluation was performed as well as a continuous intraoperative on-line monitoring of the vital parameters. The en bloc resections (multisegmental in five patients) were performed in 10 thoracic, in 16 lumbar, in two thoracolumbar lesions, and in one lumbosacral lesion. Reconstruction was performed, aiming to replace the resected columns. The specimens were submitted to histologic study of the margins. All the patients were followed, and their status was defined on clinical and imaging studies. RESULTS: In 20 patients, a wide margin was achieved, in eight a marginal margin, in one an intralesional margin. The margin was contaminated in seven patients. Surgical time was 3-21 hours (average, 12 hours). No patient died during surgery or from surgical complications. Three mechanical failures of the implants required additional surgery. One deep infection arose. The only neurologic problems observed were related to the nerve roots sectioned for oncologic purpose. No local recurrence was found at follow-up evaluation after 6-134 months (average, 30 months). CONCLUSIONS: En bloc resection can be performed in selected tumors of the spine; the indication to such major surgery must be based on the oncologic stage, and the procedure must be carefully planned. For this purpose, the Weinstein-Boriani-Biagini system could be a helpful tool. Long-term results must be weighed before a definitive statement of the indications can be made.     

MR imaging in pretruncal nonaneurysmal subarachnoid hemorrhage: is it worthwhile?

BACKGROUND and PURPOSE: The cause of pretruncal (perimesencephalic) nonaneurysmal subarachnoid hemorrhage is not known. MRI of the brain or spine is often performed to exclude any other vascular abnormalities. Its diagnostic value is not known. METHODS: We used MR imaging of the brain with routine sequences, gadolinium enhancement, and additional thin T1-weighted axial sections following a triple dose of contrast. RESULTS: We performed MR imaging of the brain in 18 patients with a pretruncal nonaneurysmal subarachnoid hemorrhage. The focal nature of the subarachnoid hemorrhage exclusively in front of the brain stem was confirmed in 14 patients studied within 7 days of the ictus. No vascular abnormalities were found in 17 cases, including 14 patients with gadolinium enhancement. An incidental capillary telangiectasia was found in 1 patient. Fluid-attenuated inverse recovery MR additionally documented blood in the sulci due to cerebrospinal fluid recirculation of blood. Five patients underwent MR imaging of the spine, and no arteriovenous malformations were found. CONCLUSIONS: MR imaging did not reveal a source of pretruncal subarachnoid hemorrhage. The cost of MR imaging probably outweighs the benefit in the evaluation of this variant of subarachnoid hemorrhage.     

A physiological approach to the evaluation of lumbosacral spinal stenosis

It has been demonstrated that MR imaging of the lumbosacral spine may frequently show stenosis in an asymptomatic individual. This article discusses the value of a physiologic test--dermatomal somatosensory evoked potentials--to assist in the diagnosis of true neurogenic spinal stenosis in patients with back and leg complaints and to aid in the separation of these patients from those whose symptoms are caused by degenerative spine disease with referred pain.     

Radiologic diagnosis and staging of head and neck squamous cell carcinoma

The predominant extracranial head and neck cancer in adults is squamous cell carcinoma. The purpose of this article is to discuss the radiographic evaluation of these patients with computed tomography (CT) or magnetic resonance (MR) imaging prior to therapeutic intervention. Specific focus is given to the efficacy of CT and MR imaging, as an adjunct to clinical staging, for evaluation of the primary tumor, and metastatic adenopathy. MR imaging, because of its improved soft tissue contrast and multiplanar capability, is probably superior to CT for evaluation of the primary tumor in patients with squamous cell carcinoma. CT, however, remains the gold standard for identifying metastatic adenopathy and in most institutions remains the study of choice for evaluating this patient population.     

Pretherapeutic staging of laryngeal carcinoma. Clinical findings, computed tomography, and magnetic resonance imaging compared with histopathology

BACKGROUND: An accurate pretherapeutic staging of laryngeal carcinoma is required for most treatment planning as well as for evaluation and comparison of the results of different treatment modalities. Neoplastic invasion of the laryngeal cartilage may have important therapeutic implications. To our knowledge, no data are available comparing the impact of endoscopic examination, computed tomography (CT), and magnetic resonance (MR) imaging on pretherapeutic staging accuracy. The purpose of our study was to determine which imaging should be used as an adjunct to other clinical examinations in the pretherapeutic staging of laryngeal carcinoma. METHODS: In this study, 40 consecutive patients with neoplasms of the larynx, who were treated surgically, were included in a prospective pretherapeutic staging protocol that included indirect laryngoscopy, direct microlaryngoscopy, contrast-enhanced CT, and gadolinium-diethylenetriamine pentaacetic acid-enhanced MR imaging at 1.5 Tesla. The surgical specimens were cut in whole-organ slices parallel to the plane of the axial CT and MR images. The histologic findings were compared with the clinical findings including the CT and MR images. The impact of each diagnostic method on pretherapeutic staging was analyzed. RESULTS: Clinical/endoscopic evaluation failed to correctly stage 17 tumors due to invasion of the paraglottic space (1 tumor), preepiglottic space (2 tumors), and extralaryngeal soft tissues (14 tumors), resulting in a pretherapeutic staging accuracy of 57.5%. Neoplastic invasion of cartilage was present in 28 patients and absent in 12 patients. Although MR imaging was more sensitive in detecting neoplastic invasion of cartilage than CT (94% vs. 67%; P = 0.001), MR imaging was less specific than CT (74% vs. 87%; P = 0.007). There was no difference between the overall accuracy of CT and MR imaging in detecting neoplastic invasion of cartilage (80% vs. 82%). The accuracy of combined clinical/endoscopic examination and CT staging was 80% and the accuracy of combined clinical/endoscopic examination and MR imaging staging was 87.5%; the difference was not statistically significant. CONCLUSIONS: Clinical/endoscopic examination alone failed to identify tumor invasion of the laryngeal cartilages and of the extralaryngeal soft tissues, resulting in a low staging accuracy (57.5%). Many pT4 (according to the International Union against Cancer TNM Staging System) tumors were clinically unrecognized. The combination of clinical/endoscopic evaluation and an additional radiologic examination, either CT or MR imaging, resulted in significantly improved staging accuracy (80% vs. 87.5%). MR imaging is significantly more sensitive but less specific than CT in detecting neoplastic cartilage invasion. Therefore, MR imaging tends to overestimate neoplastic cartilage invasion and may result in overtreatment, whereas CT tends to underestimate neoplastic cartilage invasion and may lead to inadequate therapy.     

Magnetic resonance imaging of primary skeletal neoplasms

The primary role of magnetic resonance (MR) imaging of skeletal neoplasms is that of staging. Understanding the staging process and selection of the proper imaging planes and pulse sequences is essential for proper staging. To date, image features are not specific for histologic type. In addition, there are still pitfalls with MR imaging for evaluating recurrent tumor or following therapeutic response to treatment. Dynamic gadolinium studies and spectroscopy may improve the future overall specificity for MR imaging.     

Spinal subdural enhancement after suboccipital craniectomy

PURPOSE: To characterize transient intraspinal subdural enhancement (potentially mimicking the subarachnoid spread of tumor) seen on MR images in some children after suboccipital craniectomy for posterior fossa tumor resection. METHODS: Radiologic and medical records of 10 consecutive children who had MR imaging for spinal staging after resection of posterior fossa tumor during a 9-month period were reviewed retrospectively. In addition, one case with similar findings of intraspinal enhancement on spinal staging MR images obtained at another institution was included in the review. RESULTS: Intraspinal enhancement thought to be subdural was seen in four of 10 patients undergoing spinal staging MR imaging 6 to 12 days after surgery. In these four patients, MR studies 50 to 18 days later, without intervening treatment, showed resolution of the abnormal enhancement. A fifth patient (from another institution) with similar intraspinal enhancement underwent CT myelography 4 days later, which showed no subarachnoid lesions. No metastases have developed in any of these five patients during the 2.5- to 3.5-year follow-up period. conclusions: From analysis of the MR appearance and on the basis of prior myelographic experience, we suggest an extraarachnoid, probably subdural, location of this enhancement. Awareness of this phenomenon will reduce the rate of false-positive diagnoses of metastatic disease. Preoperative spinal staging should be considered for patients undergoing suboccipital craniectomy.     

Primary muscle lymphoma: clinical and imaging findings

PURPOSE: To assess the clinical and imaging findings in primary muscle lymphoma. MATERIALS AND METHODS: Seven patients with biopsy-proved primary muscle lymphoma without evidence of systemic disease underwent imaging with plain radiography or computed tomography (CT) and magnetic resonance (MR) imaging. Four underwent bone scintigraphy, and two underwent gallium scintigraphy and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) before and after therapy. RESULTS: Plain radiographs at initial examination (n = 5) showed no bone abnormalities. Soft-tissue masses and bone marrow involvement showed isoattenuation at CT (n = 3), but at MR imaging (n = 7), all masses demonstrated increased signal intensity on T2-weighted images that involved multiple muscle compartments and typically spanned a long segment of the extremity. Adjacent bone disease was less extensive than muscle disease, and, in most cases, subcutaneous stranding or extension was observed adjacent to the masses. Good size correlation was observed between findings at MR imaging, gallium scintigraphy, and FDG PET. Two patients developed recurrent multifocal muscle lymphoma several years after initial examination. CONCLUSION: The presence of an extensive soft-tissue mass with infiltration of adjacent subcutaneous fat and minimal or no extension into the bone marrow cavity at MR imaging and normal plain radiographic findings may suggest primary muscle lymphoma.     

Adolescent obesity increases significantly in second and third generation U.S. immigrants: the National Longitudinal Study of Adolescent Health

PURPOSE: Our aim was to determine the precision of MR imaging evaluation of perineural spread of head and neck tumors. METHODS: Nineteen patients had complete extirpation of head and neck tumors (10 squamous cell carcinomas, four adenoid cystic carcinomas, one poorly differentiated carcinoma, one salivary duct carcinoma, one mucoepidermoid carcinoma, one chordoma, and one meningioma) with histologic confirmation of perineural spread. Findings at presurgical contrast-enhanced MR imaging were compared with findings at pathologic examination. RESULTS: The sensitivity of MR imaging for detection of perineural spread was 95%; however, the sensitivity for mapping the entire extent of perineural spread fell to 63%. CONCLUSION: MR imaging may fail to depict microscopic foci of perineural tumor infiltration, leading to underestimation of the extent of perineural spread. Nevertheless, with careful analysis of foraminal architecture and MR enhancement patterns, one can reliably identify the presence if not the extent of perineural spread.     

Only visual impressions are almost always present in long-term memories, and reported completeness, accuracy, and verbalizability of recollections increase with age

PURPOSE: To stage advanced cervical carcinoma with conventional or pharmacokinetic magnetic resonance (MR) imaging by correlating imaging findings with whole-mount specimens and histopathologic findings. MATERIALS AND METHODS: Twenty-six adult patients with primary cervical cancer (stages IIB-IVA) underwent T2-weighted turbo spin-echo (SE) MR imaging; gadolinium-enhanced, T1-weighted SE MR imaging; and gadolinium-enhanced, saturation-recovery, turbo fast low-angle shot MR imaging. All imaging findings were correlated with the whole-mount specimens and histopathologic findings. Signal intensity changes versus time were analyzed by using a pharmacokinetic model and parameter values displayed as a color-coded overlay. RESULTS: Histopathologic stages were IIB (n = 9), IIIB (n = 1), and IVA (n = 16). The overall accuracy for tumor staging was 73% for T2-weighted, 81% for T1-weighted, and 92% for pharmacokinetic MR imaging. Pharmacokinetic MR imaging was accurate (90%) in the diagnosis of tumor extension into the bladder and/or rectal wall but inaccurate (69%) in that of parametrial invasion. T2-weighted images were most accurate (86%) in the assessment of parametrial tumor extension but less accurate (69%) in that of bladder or rectal invasion. CONCLUSION: T2-weighted turbo SE images are still superior to contract medium-enhanced T1-weighted SE or pharmacokinetic MR images in the diagnosis of parametrial infiltration by uterine cervical carcinoma. However, pharmacokinetic MR imaging is a promising method for demonstrating and staging IVA disease.     

Knee problems--imaging techniques

Standard radiographs still represent the standard imaging method in knee abnormalities. Major advantages include high spatial resolution, low cost, high availability and standardized imaging technique. Because there is an increasing pressure on the cost of health care, additional imaging should only be employed based on a working hypothesis. In most cases MR imaging is most suitable for further diagnosis. In internal knee derangements MR imaging has been shown to have a high negative predictive value, thus obviating unnecessary surgery. MR imaging also is the imaging method of choice in the detection and follow-up of arthritis, in the detection, staging and follow-up of malignant neoplasms, and in the detection of occult fractures. Ultrasonography is useful in the characterization of superficial soft-tissue abnormalities, but has not gained high acceptance in searching for internal derangements of the knee. Scintigraphy is competing with MR imaging in the early detection of bone abnormalities and for follow-up. However, it is less expensive and can be employed for the evaluation of multilocular processes. CT has a limited role in the evaluation of complex fractures mainly of the tibial plateau.     

Counterflow centrifugal elutriation: present and future

Only single cases with rheumatoid arthritis of the thoracic spine with vertebral subluxation have been reported to date. In a review of 100 patients with severe rheumatoid arthritis who had undergone occipitocervical fusion, arthritis of the upper thoracic spine with subluxation was discovered on conventional radiographs in four patients. Two additional patients were found elsewhere. Magnetic resonance imaging (MRI) was performed in three of the patients, confirming the diagnosis of subluxation of the upper thoracic vertebrae. In addition, MRI revealed encroachment on the anterior subarachnoid space and compression of the spinal cord.     

Neuroimaging findings in patients on immunosuppressive therapy: experience with tacrolimus toxicity

OBJECTIVE: The purpose of this study is to describe the neuroimaging (CT and MR imaging) findings in liver transplant patients who develop severe neurologic side effects during immunosuppressive therapy with tacrolimus and to correlate these findings with clinical signs and tacrolimus levels in blood. SUBJECTS AND METHODS: Brain CT and/or MR imaging was performed on six patients who developed neurologic symptoms while receiving tacrolimus in the post-transplant period. All patients were evaluated by the neurology staff, and imaging studies were independently interpreted by three neuroradiologists. Trough tacrolimus levels in blood were measured with the IMX immunoassay and were correlated with neurologic symptoms and imaging findings. RESULTS: Imaging abnormalities were observed in five of six patients during the course of their neurologic illnesses. For each patient, neurologic symptoms began when the tacrolimus level in blood was at a peak, exceeding the therapeutic limit in all but one case. In five patients, neurologic symptoms eventually resolved after the tacrolimus dose was reduced or after the drug was stopped. Multifocal low attenuation of white matter was the predominant finding seen on CT images, and matching hyperintense white matter foci were observed on long-TR MR images. In three patients, clinical recovery was accompanied by reversal of the white matter abnormalities seen on CT and MR images. CONCLUSION: Immunosuppressive therapy with tacrolimus may produce neurologic side effects that are associated with brain CT and MR imaging abnormalities. Resolution of symptoms and reversal of imaging findings occur when the tacrolimus dose is reduced.     

Magnetic resonance imaging in patients with bone marrow disorders

Magnetic resonance imaging (MRI) provides a non-invasive means to evaluate a large fraction of marrow in less than one hour. Marrow disorders produce non-specific changes in marrow signal intensities which primarily reflect changes in proportions of fat and cellular elements. The pattern of these signal changes narrows the differential diagnosis, and the combination of these features with the clinical context allows interpretations which are clinically useful in many ways. These include: 1) the diagnosis of avascular necrosis (and its distinction from other causes of joint pain), 2) detection of osteomyelitis, 3) differential diagnosis of hypoplastic disorders, 4) staging of lymphomas and myeloma, 5) selection of patients for autologous bone marrow transplant, 6) objective measures of marrow response to therapy, 7) detection of leukemic transformation, and 8) improved detection of marrow disease (primary or secondary) in patients with otherwise unexplained bone pain.     

Primary bone and metastatic tumors of the cervical spine

Cervical spine tumors, whether primary bone tumors or metastatic tumors, are rare. The possibility of tumors existing must be considered in the differential diagnosis of patients with persistent neck pain, with or without neurologic symptoms, particularly in those with significant pain at night. The clinical presentation is extremely variable, though a history of malignancy should always raise the concern for recurrence. The evaluation and diagnostic assessment includes a thorough physical examination. Radiographic imaging is usually initiated with plain radiographs and additional advanced imaging obtained as indicated. Using appropriate biopsy principles and techniques, tissue is obtained for histologic determination of the suspected lesion before surgical intervention. Treatment options are extremely variable and depend on many factors, including tumor type, location, and patient preference. Treatment warrants a multidisciplinary approach from experienced physicians and is most successfully accomplished in referral centers. Oncologic staging using the Enneking staging system, followed by surgical staging using the Weinstein, Boriani, Biagini system, will aid in the accurate characterization of the tumor load, maximize surgical goals, assure use of appropriate terminology, and provide optimal communication among treatment centers regarding tumor characteristics, treatment efforts, and results.     

Thoracic aortic dissection: diagnosis with transesophageal echocardiography versus MR imaging

PURPOSE: To compare transesophageal echocardiography (TEE) and magnetic resonance (MR) imaging in the diagnosis of dissection of the thoracic aorta. MATERIALS AND METHODS: Thirty-one consecutive patients with clinically suspected aortic dissection and 10 postoperative patients underwent transesophageal color Doppler echocardiography and MR imaging. Imaging results were compared at independent double-blind readings. Final diagnosis was obtained from consensual review of all corroborative studies. RESULTS: MR imaging depicted the intimal flap in 95% of aortic dissections; TEE, in 86% (P < .05). In surgical patients, the sensitivity of MR in detection of residual dissection was 100% versus 86% with TEE (P < .05). The inferior extent of the dissected lumen was seen only with MR imaging. False-positive results occurred in two cases with TEE and in one with MR imaging. CONCLUSION: MR imaging is superior to TEE in the evaluation and follow-up of dissection of the thoracic aorta. Because the availability of MR is limited, however, TEE should remain the standard modality for diagnosis.     

Putamen volume in idiopathic focal dystonia

PURPOSE: To determine the accuracy of magnetic resonance (MR) imaging in evaluating the invasive cervical carcinoma response to concurrent chemotherapy and radiation therapy. MATERIALS AND METHODS: MR imaging was performed before and after concurrent chemotherapy and radiation therapy in 18 patients with locally invasive cervical carcinoma. Surgery followed neoadjuvant therapy in all patients. The presence of a lesion, signal intensity, zonal anatomy integrity, vaginal and parametrial invasion, and lymph node enlargement was determined. Posttreatment MR and histopathologic findings were correlated. RESULTS: Fourteen patients had histopathologic confirmation of MR findings: Twelve had true-negative and two had true-positive findings. (Two had microscopic neoplastic foci beyond the spatial resolution of MR images; these foci do not change surgical treatment planning and probably do not influence prognosis. Therefore, these two patients were considered to have complete response). Four patients had false-positive findings; the hyperintense lesion on posttreatment MR images was due to a tunnel cluster pattern (focal hyperplasia of the endocervical glands with inflammation) in three patients and necrosis in one patient, without any evidence of neoplastic tissue. Thirty-three of 36 parametrial halves and 67 of 72 vaginal fornices were correctly interpreted on posttreatment images. Involvement of three parametrial halves and five fornices was overestimated at MR, because edema or inflammation was not distinguishable from tumor. CONCLUSION: MR imaging is 78% accurate in evaluation of tumor response; in 22% of patients, however, benign conditions were not distinguishable from tumor.     

Prostatic cryosurgery: use of MR imaging in evaluation of success and technical modifications

PURPOSE: To evaluate the usefulness of contrast material-enhanced magnetic resonance (MR) imaging in objective assessment of prostatic cryosurgery and the role of MR imaging in the modification of prostatic cryosurgical technique. MATERIALS AND METHODS: Thirty-eight consecutive patients with localized (T1-3, N0, M0) prostatic adenocarcinoma treated with prostatic cryosurgery underwent MR imaging without contrast enhancement before cryosurgery and unenhanced and gadolinium-enhanced MR imaging within 1-3 weeks after cryosurgery. The first 20 patients also underwent MR imaging at 3 months after cryosurgery. MR imaging findings were correlated with those from transrectal ultrasound-directed prostatic staging biopsy. RESULTS: Cryonecrotic prostate was identified as avascular regions characterized by absolute signal void on contrast-enhanced images. With progressive modification of cryosurgical technique, complete cryoablation of the prostate was achieved in the latter nine of the 38 patients. When cryoablation was considered complete according to MR imaging criteria, findings invariably correlated with those at biopsy, with no residual prostate tissue or tumor. CONCLUSION: Gadolinium-enhanced MR imaging of the prostate after cryosurgery provides a highly accurate means of monitoring success. Objective MR imaging findings allow modifications to the technology and technique, resulting in optimal therapeutic results with prostatic cryosurgery.